PhiPsi File System Manual

This manual describes the file formats (input files, output files, restart files) that the PhiPsi solver reads and writes, plus the file-to-visualization mapping used by the companion PPView post-processor.
Author: Fang Shi
Website: http://phipsi.top
Email: shifang@hyit.edu.cn / shifang@ustc.edu.cn
Updated on 2026-06-29.

Click here to download the latest version of PhiPsi.

Click here to download the latest version of PPView.

For keyword (.kpp) reference, see the companion PhiPsi Keywords Manual.

Contents of this file system manual

File naming rules

Input files

Keywords input (.kpp)

Required mesh files (.node, .elem)

Boundary-condition files (.boux/.bouy/.bouz, .buxn/.buyn/.buzn)

Force / point-load files (.focx/.focy/.focz)

Initial-condition files for dynamics (.ive*, .iac*, .idp*)

Degree-of-freedom coupling files (.dofx/.dofy)

Field-problem input files (.fbvl, .fbqn, .fbiv)

Hydraulic-fracturing wellbore files (.bhpc)

Earthquake node list (.eqnl)

3D model boundary-detection outputs (.outl/.outa/.outn)

PPView geometry metadata (.boud, .focd)

Output files

VTK files (.vtk, CRACK.vtk)

Displacement files (.disp_, .disn_, .dien_, .disg_, .dipc_, .dinc_, .veln_, .acln_)

Stress files (.strn_, .strg_, .stnc_, .sttn_, .elss_)

Strain files (.sran_, .srac_)

Gauss-point files (.gcor_, .disg_, .damg_, .elgn_, .strg_)

SIF / fracture-energy files (.sifs_, .sift_, .prst_, .enee)

Crack coordinates (.crax/.cray/.craz, .crxo/.cryo, .cnox/.cnoy/.cnoz)

Crack meshes (.cms1/.cms2/.cms3, .cmso, .cmap, .cape, .capf, .ctap)

Crack vertex and tangent files (.cvpx/.cvpy/.cvpz, .cvxx/.cvxy/.cvxz, ...)

Crack calculation-point files (.apex/.apey, .cori, .cpre, .cvel, .cqua, .cohx/.cohy, .crrd)

XFEM enrichment files (.ennd, .elty, .posi, .elts, .posh, .ennh, ...)

Crack-tip and baseline files (.celt, .celv, .celj, .celc, .ctty, .blab, .blvx/.blvy/.blvz, .tere)

Crack-node S1 vector files (.cndx/.cndy/.cndz)

Hole and inclusion files (.hlcr, .ehcr, .jzcr, .jzpx/.jzpy)

Cross-interface files (.cscr)

Natural-fracture files (.nfcx/.nfcy/.nfcz, .ncrx/.ncry)

Energy history files (.ener, .edye, .edtm, .edap)

Crack length history (.dcrl, .dprl, .idtm, .iite, .ilth, .ipre)

Dynamic files (.idtm, .edtm, .dcrl, .dprl)

Lumped mass files (.lpmf_, .lpmx_, .lpma_)

Hydraulic-fracturing output files (.hftm, .injp, .wbfp, .wbpt, .ihft, .icpt, .icpt_LS, .icpt_CT)

Proppant output files (.ccon_, .pokf_, .cond_, .wpnp_, .epcr_, .Saved_Filename)

Contact, cohesive and element-state files (.elcs_, .elco_, .elss_, .kiel_)

DOF / surface-load force files (.fxdf_, .fydf_, .fzdf_, .fxsl_, .fysl_, .fzsl_)

Stiffness-matrix files (.skxf, .csrn_, .csra_, .csrj_, .csri_)

3D fluid-crack files (.fenx/.feny/.fenz, .fnnx/.fnny/.fnnz, .fnux/.fnuy/.fnuz, .fnlx/.fnly/.fnlz, .fexx/.fexy/.fexz/.feyx/.feyy/.feyz/.fezx/.fezy/.fezz, .cpfn_, .cpno_, .ccpx/.ccpy/.ccpz, .cnlx/.cnly/.cnlz, .cmse_)

Miscellaneous files (.fraz, .seed, .post, .fdcu, .fccu, .rbco_, .fdvl, .ecfv, .sccx/.sccy/.sccz, .scdx/.scdy/.scdz)

Console / log files (PhiPsi_Console_Window.log, current_folder.dat)

PPView file-reading map

Cloud plot / contour rendering

Curve plot / line chart rendering

Vector plot / arrow rendering

Crack visualization (2D and 3D)

Animation playback

Data format examples

Example A — 2D simple FEM (2d_fem)

Example B — 2D crack propagation (2d_L_shaped_specimen)

Example C — 3D uniaxial tension (3d_uniaxial_tension)

Example D — 3D hydraulic fracturing (3d_hf_toughness_dominated)

Quick-reference summary tables

All input-file summary table

All output-file summary table

File naming rules

All PhiPsi input and output files share a common base path, which is built by joining the two keywords *Work_Directory and *Filename from the .kpp input. Every file in this manual has the form <basename>.{ext}[_{suffix}].

*Work_Directory
X:\PhiPsi_Work\FEM

*Filename
FEM

produces basename = X:\PhiPsi_Work\FEM\FEM. From that base, the solver reads FEM.node, FEM.elem, FEM.boux, … and writes FEM.disp_1, FEM.disn_1, FEM.sifs_1, FEM.ener, ….

Input files (read by the solver) use a fixed extension pattern; they have no step-number suffix. The extension alone selects what kind of data is in the file.
Output files (written by the solver) usually carry a per-step suffix _i where i is the load-step (substep) index. For VTK files the step index is zero-padded to 5 digits (_00001.vtk); for other outputs the step number is written without leading zeros (_1, _2, …). A few output files do not carry a step suffix — they are written once (e.g. .ener, .seed, .post, .wbfp) or once per analysis type (e.g. .hlcr for holes).
Some output files can be written as plain ASCII text or as a binary stream. The choice is governed by *Key_Data_Format (1 = ASCII, 2 = binary). When a file is documented as "Format: ASCII / Binary", the binary stream mirrors the ASCII column layout but with no fixed-width formatting — values are written as raw floating-point records.

Input files

Keywords input (.kpp)

*.kpp - Keywords input file. Drives every PhiPsi run; selects analysis type, mesh files, material, solver, sub-steps, and which outputs are produced.
- Pattern: <Work_Directory>\*Work_Directory points here*.kpp
- Required: Yes — solver aborts if either *Work_Directory or *Filename is missing.
- Format: Plain text, *Keyword lines followed by their value(s); lines starting with % are comments.
- Dimensions: both
- Convention: Keywords are case-insensitive; supports parameter definitions (num_of_crack = 2) and basic arithmetic (1+1, (15e6-10e6)*(3-1)).
- Reference: See PhiPsi Keywords Manual for the complete list of 200+ keywords.
Example:
```
% Working directory and filename.
*Work_Directory
X:\PhiPsi_Project\Test_Examples\2d_fem

*Filename
fem_2d

*Key_Analysis_Type
1 % Quasi-static.

*Key_Type_2D
1 % Plane stress.

*Key_SLOE
6 % MUMPS solver.

*Num_Substeps
1

*Material_Para_1
70.0e9,0.3,2700.0,1.0,1.0e6,1.0e6,100.0e6,0.0,...
```

Required mesh files (.node, .elem)

*.node - Node coordinate file.

Pattern: <basename>.node
Required: Yes — solver aborts if missing.
Dimensions: 2D = X Y; 3D = X Y Z.
Format: ASCII, whitespace-separated real numbers; one node per line; no header. Read by Tool_Read_File after Tool_Count_Lines counts rows.
Units: meters (SI) or millimeters (mm-ton-s) depending on *Key_Unit_System.

Example (Test_Examples/2d_L_shaped_specimen/2d_L_shaped_specimen.node):

  0.00000000E+00   0.00000000E+00 
  0.25000000E+00   0.00000000E+00 
  0.16666667E-01   0.00000000E+00 
  0.33333333E-01   0.00000000E+00 
  0.50000000E-01   0.00000000E+00 
  0.66666667E-01   0.00000000E+00 
  0.83333333E-01   0.00000000E+00 
  0.10000000E+00   0.00000000E+00 
  0.11666667E+00   0.00000000E+00 
  0.13333333E+00   0.00000000E+00

3D example (Test_Examples/3d_uniaxial_tension/3d_uniaxial_tension.node):

  0.00000000E+00   0.00000000E+00   0.00000000E+00
  0.11000000E+02   0.00000000E+00   0.00000000E+00
  0.36666667E+00   0.00000000E+00   0.00000000E+00
  0.73333333E+00   0.00000000E+00   0.00000000E+00
  0.11000000E+01   0.00000000E+00   0.00000000E+00
  0.14666667E+01   0.00000000E+00   0.00000000E+00
  0.18333333E+01   0.00000000E+00   0.00000000E+00
  0.22000000E+01   0.00000000E+00   0.00000000E+00

*.elem - Element connectivity and material-number file.

Pattern: <basename>.elem
Required: Yes.
Dimensions: 2D = 5 columns (N1 N2 N3 N4 Mat); 3D = 9 columns (N1 N2 N3 N4 N5 N6 N7 N8 Mat).
Format: ASCII, whitespace-separated integers; one element per line; no header.
Units: node indices are 1-based integers; Mat references a *Material_Para_<n> keyword in the .kpp.
Element type: 2D = 4-node quad (linear); 3D = 8-node hexahedron (linear). Triangular 6-node elements are also supported by some analyses (see VTK cell types in the VTK output section).

2D example (Test_Examples/2d_fem/fem_2d.elem):

      1.       3.      81.      62.       1.
      3.       4.     100.      81.       1.
      4.       5.     119.     100.       1.
      5.       6.     138.     119.       1.
      6.       7.     157.     138.       1.
      7.       8.     176.     157.       1.
      8.       9.     195.     176.       1.
      9.      10.     214.     195.       1.
     10.      11.     233.     214.       1.
     11.      12.     252.     233.       1.

3D example (Test_Examples/3d_uniaxial_tension/3d_uniaxial_tension.elem):

      1.       3.     121.     120.    1072.    1073.    6723.    4722.       1.
      3.       4.     150.     121.    1073.    1113.    7883.    6723.       1.
      4.       5.     179.     150.    1113.    1153.    9043.    7883.       1.
      5.       6.     208.     179.    1153.    1193.   10203.    9043.       1.
      6.       7.     237.     208.    1193.    1233.   11363.   10203.       1.
      7.       8.     266.     237.    1233.    1273.   12523.   11363.       1.

Boundary-condition files (.boux/.bouy/.bouz, .buxn/.buyn/.buzn)

These six files declare nodal Dirichlet boundary conditions.

*.boux - X-direction zero-displacement (fixed DOF) node list.
- Pattern: <basename>.boux
- Required: No (warned if missing on a problem with intended fixed BCs).
- Dimensions: 2D and 3D.
- Format: ASCII, one node index per line; no header.
- Reading: Num_Bou_x = Tool_Count_Lines(temp_name); then Bou_x = int(Temp_DATA(:,1)).
Example (Test_Examples/2d_fem/fem_2d.boux):
```
 1.
 42.
 62.
 63.
 64.
 65.
 66.
 67.
 68.
 69.
```
*.bouy - Y-direction zero-displacement node list. Same format as .boux. In 2D and 3D.

Example (Test_Examples/2d_fem/fem_2d.bouy):
```
      1.
     42.
     62.
     63.
     64.
     65.
     66.
     67.
     68.
     69.
```
*.bouz - Z-direction zero-displacement node list. 3D only.
- Format: identical to .boux/.bouy.
*.buxn - Non-zero prescribed X displacement. Format: Node_ID Value (2 columns).
*.buyn - Non-zero prescribed Y displacement. Same as .buxn.
*.buzn - Non-zero prescribed Z displacement. 3D only.
- Required: No; if absent, only zero BCs are read.
- Format: ASCII, node_id value per line.
- Units: same as .node (m or mm).

Force / point-load files (.focx/.focy/.focz)

*.focx - Nodal point load in X direction.
- Pattern: <basename>.focx
- Required: No.
- Format: ASCII, Node_ID Value per line (2 columns); no header.
- Units: Newtons in SI; tonnes of force per node in mm-ton-s.
Example (Test_Examples/2d_L_shaped_specimen/2d_L_shaped_specimen.focx — single row):
```
 0.137028414927E-04 0.247500000000E-01
```

*.focy - Y-direction nodal force. Same format.

Example (Test_Examples/2d_fem/fem_2d.focy):

     22.   0.22500000E+05
    462.   0.22500000E+05
    482.   0.45000000E+05
    483.   0.45000000E+05
    484.   0.45000000E+05
    485.   0.45000000E+05
    486.   0.45000000E+05
    487.   0.45000000E+05
    488.   0.45000000E+05
    489.   0.45000000E+05

*.focz - Z-direction nodal force. 3D only. Same 2-column format.

3D example (Test_Examples/3d_uniaxial_tension/3d_uniaxial_tension.focz):

    962.   0.33586629E+06
   1003.   0.33586629E+06
   1004.   0.67173257E+06
   1005.   0.67173257E+06
   1006.   0.67173257E+06

Initial-condition files for dynamics (.ive, .iac, .idp*)

These nine files supply initial nodal velocity / acceleration / displacement for implicit-dynamic (*Key_Analysis_Type = 2) and explicit-dynamic analyses.

*.ivex, .ivey, .ivez - Initial nodal velocity per DOF.
*.iacx, .iacy, .iacz - Initial nodal acceleration per DOF.
*.idpx, .idpy, .idpz - Initial nodal displacement per DOF (3D only via Read_Geo_3D.F90; for 2D use .buxn/.buyn instead).
- Pattern: <basename>.{ive|iac|idp}{x|y|z}
- Required: No.
- Format: ASCII, Node_ID Value per line; 2 columns.
- Units: m/s for velocity, m/s² for acceleration, m for displacement.

Degree-of-freedom coupling files (.dofx/.dofy)

*.dofx - Multi-point-constraint coupling set in X DOF.
*.dofy - Multi-point-constraint coupling set in Y DOF.
- Format: ASCII, Set_Number Node_ID per line (2 columns). Nodes with the same Set_Number are tied together in the X (or Y) DOF.
- Required: No.
- Example: 1 5\n1 6\n2 10 ties nodes 5 and 6 together in the coupled group 1; node 10 is alone in group 2.

Field-problem input files (.fbvl, .fbqn, .fbiv)

Used with *Key_Analysis_Type = 15 (field problem such as heat transfer or pore pressure). 2D-only.

*.fbvl - Field-problem boundary value list. Each row: Node_ID Value. Zero values are treated as fixed-Dirichlet; non-zero values are applied as a known scalar (e.g. prescribed temperature).
*.fbqn - Boundary flux (Neumann). Same 2-column format. Units depend on the field variable (W/m² for heat, m/s for pore-flow).
*.fbiv - Initial value per node. Same 2-column format. Sets the starting scalar value at each listed node.

Hydraulic-fracturing wellbore files (.bhpc)

*.bhpc - Bottom-hole-pressure time curve.
- Pattern: <basename>.bhpc
- Required: Conditional — read only when *Key_Analysis_Type is 16 or 17 (wellbore analysis), *Key_Gas_Production = 1, and *Key_Changing_BHP = 1.
- Format: ASCII, two columns Time Pressure per row.
- Units: seconds and Pa.

Earthquake node list (.eqnl)

*.eqnl - List of node IDs to apply earthquake acceleration.
- Pattern: <basename>.eqnl
- Required: Conditional — read only when *EQ_Ac_nodes_list_method = 2 (list method).
- Format: ASCII, one node index per line; no header.
- Limit: up to 5000 nodes.

3D model boundary-detection outputs (.outl/.outa/.outn)

These are written by the solver (in Read_Geo_3D.F90 and helpers) as a side-effect of importing the 3D geometry; they are not user input but appear in the working directory after a 3D run.

*.outl - 3D model outer boundary edge list. Format: Node1 Node2 per row (integers).
*.outa - 3D model outer surface-area edges. Same 2-column format.
*.outn - 3D model exterior surface node numbers. Format: one node index per line.

PPView geometry metadata (.boud, .focd)

These pipe-delimited text files are written by PPView when the user builds the model graphically; they mirror what .boux/.bouy/.focx/.focy mean but can express boundary-conditions and loads as functions of coordinate ranges or single coordinates.

*.boud - Boundary-condition metadata.

Format: one pipe-delimited record per line:

fix_nodes|X|1,2,3,4,5
fix_coord_single|0|0.0|0.001|All
fix_coords_range|0|10|0|5|0|0|0.001|X|Y
fix_all_boundaries|left

*.focd - Applied-force metadata.
- Format: pipe-delimited:
```
force_nodes|Y|1000.0|22,462,482
force_coord_single|y|0.05|0.001|0|225000|0
pressure_timevar|0|10|0|5|0|0|0.001|csv_file.csv
init_vel|0|10|0|5|0|0|0.001|0|0|-9.8
```
PPView translates these records back into the simple .boux/.bouy/.focx/.focy/.focz ASCII lists before invoking the solver.

Output files

VTK files (.vtk, CRACK.vtk)

The legacy ASCII VTK files written by Save_vtk_file.f90 and Save_vtk_file_for_Crack.f90. Both are enabled by *Key_Save_vtk = 1.

*{Full_Pathname}_NNNNN.vtk - Main solution snapshot at substep NNNNN.
- Pattern: <basename>_<isub5>.vtk where <isub5> is the 5-digit zero-padded substep index (e.g. 00001).
- Required: No — gated by *Key_Save_vtk.
- Format: Legacy ASCII VTK (# vtk DataFile Version 4.0 header).
- Contents (in order):
 - POINTS Num_Node double — (X, Y, Z) triples, F12.6 per coordinate. For 2D, Z is 0.0.
 - CELLS Num_Elem ind — element connectivity, 0-indexed (1 is subtracted from each node ID before writing). For 2D quad: 4 n1 n2 n3 n4. For 3D hex: 8 n1 n2 … n8.
 - CELL_TYPES Num_Elem — VTK cell-type integer per element (5 = tri, 9 = quad, 10 = tetrahedron, 12 = hexahedron, 22 = quadratic tri, etc.).
 - CELL_DATA Num_Elem block:
 - SCALARS Material_ID int and LOOKUP_TABLE default
 - SCALARS Element_ID int and LOOKUP_TABLE default
 - SCALARS Element_Permeability_{xx|yy|zz|xy|yz|xz} double (if pore-pressure elements allocated)
 - SCALARS Enriched_Element_Type int (if Enrich_Freedom > 0)
 - POINT_DATA Num_Node block:
 - VECTORS Displacement double — (Ux, Uy, Uz) per node, E20.12.
 - SCALARS stress_xx|yy|xy|vm double for 2D; stress_xx|yy|zz|xy|yz|xz for 3D (if allocated).
 - SCALARS Node_Number integer.
 - SCALARS Enriched_Node_Type int (if enriched).
Example (Test_Examples/2d_fem/fem_2d_00001.vtk):
```
# vtk DataFile Version 4.0
X:\PhiPsi_Project\Test_Examples\2d_fem\fem_2d - results from increment 00001
ASCII
DATASET UNSTRUCTURED_GRID

POINTS 861 double
 0.050000 0.000000 0.000000
 -0.040000 0.030000 0.000000
 0.049610 0.006229 0.000000
 0.048448 0.012361 0.000000
 0.046531 0.018300 0.000000
 0.043888 0.023955 0.000000
 0.040562 0.029236 0.000000
 0.036604 0.034061 0.000000
 0.032075 0.038356 0.000000
 0.027047 0.042053 0.000000
 0.021598 0.045095 0.000000
 0.015811 0.047434 0.000000
 0.009779 0.049034 0.000000
 0.003594 0.049871 0.000000
 -0.002647 0.049930 0.000000
```
- Compatibility: Open in ParaView, VisIt, F3D, or any VTK-compatible viewer. The cell-connectivity numbering is 0-based (1 is subtracted from each node ID before writing).
*{Full_Pathname}_CRACK_NNNNN.vtk - Crack geometry only (separate file for visualisation clarity).
- Pattern: <basename>_CRACK_<isub5>.vtk.
- Contents:
 - 2D: VTK_LINE cells (cell type 3) — 2 n1 n2 per row.
 - 3D: VTK_TRIANGLE cells (cell type 5) — 3 n1 n2 n3 per row.
 - SCALARS Crack_Node_Aperture double (3D only) per crack node.
 - SCALARS Crack_Node_Number integer.
 - SCALARS Crack_Element_ID int.

Displacement files (.disp_, .disn_, .dien_, .disg_, .dipc_, .dinc_, .veln_, .acln_)

All written by Save_Disp.f90, Save_Velocity_Accel.f90, and the related routines. ASCII vs binary is controlled by *Key_Data_Format.

*.disp_ - Global displacement vector in raw global-DOF order.

Pattern: <basename>.disp_<isub>.

Format: ASCII = one (E20.12) value per line; binary = unformatted stream of floating-point records (8 bytes per value for double precision).

Columns: 1 (raw DISP(i) for i = 1 … Total_FD).

Ordering: Ux1, Uy1, Uz1, Ux2, Uy2, Uz2, … for 3D; Ux1, Uy1, Ux2, Uy2, … for 2D.

Units: SI (m). Not unit-system-scaled at write time.

*.disn_ - Nodal displacements indexed by node number — the user-friendly companion to .disp_.

Pattern: <basename>.disn_<isub>.

Format:

2D ASCII: I8, ',' , E20.12, ',' , E20.12 per line → node_id, Ux, Uy (comma-separated).

3D ASCII: I8, 3E20.12 → space-separated node_id Ux Uy Uz.

Binary: unformatted stream of (Ux, Uy) (2D) or (Ux, Uy, Uz) (3D) per node.

Unit scaling: Yes — divided by 1000.0 to mm when *Key_Unit_System = 2.

Example (Test_Examples/2d_fem/fem_2d.disn_1):

1, 0.000000000000E+00, 0.000000000000E+00 2, 0.309792344217E-03, 0.200022243102E-02 3, 0.306508276247E-04, -0.422207813393E-04 4, 0.661986220995E-04, -0.714963121533E-04 5, 0.116443200093E-03, -0.937367347085E-04 6, 0.181700145801E-03, -0.103665261266E-03 7, 0.259776862462E-03, -0.974530658974E-04 8, 0.347292854805E-03, -0.718664920552E-04 9, 0.440084114000E-03, -0.246253768389E-04 10, 0.533547239550E-03, 0.455736716968E-04

3D example (Test_Examples/3d_uniaxial_tension/3d_uniaxial_tension.disn_1):

1 0.000000000000E+00 0.000000000000E+00 0.000000000000E+00 2 -0.158000824552E-02 0.000000000000E+00 0.000000000000E+00 3 -0.599530622114E-04 -0.198353082554E-05 0.000000000000E+00 4 -0.119662125493E-03 -0.473063658899E-05 0.000000000000E+00 5 -0.178898410344E-03 -0.864250808527E-05 0.000000000000E+00 6 -0.237351373110E-03 -0.138088347514E-04 0.000000000000E+00 7 -0.294744765137E-03 -0.201261481292E-04 0.000000000000E+00 8 -0.350861002901E-03 -0.273768250648E-04 0.000000000000E+00 9 -0.405543687855E-03 -0.352738546285E-04 0.000000000000E+00 10 -0.458697601816E-03 -0.434876069018E-04 0.000000000000E+00

*.dien_ - Enriched-DOF displacement vector (XFEM).

Pattern: <basename>.dien_<isub>.

Format: Same as .disn_ (2D comma-separated, 3D space-separated) but values are zero for non-enriched nodes.

*.edei_ - Enriched-DOF index mapping. Format: node_id, enriched_index per row.

*.disg_ - Gauss-point displacements.

Format: 2D = (I8, 2E20.12) per row → gp_id, Ux, Uy. 3D adds Uz.

*.dipc_ - Cylindrical-coordinate raw DOF vector. Enabled when *Key_CoorSys = 2.

*.dinc_ - Cylindrical-coordinate nodal displacement, same indexing scheme as .disn_.

*.veln_ - Per-node velocity (dynamic analysis only).

Format: 2D = (I8, ',', E20.12, ',', E20.12) → node_id, vx, vy. 3D = (I8, 3E20.12) → node_id, vx, vy, vz.

Units: m/s (SI) or mm/s (mm-ton-s).

*.acln_ - Per-node acceleration (dynamic analysis only).

Format: identical layout to .veln_. Units: m/s² or mm/s².

Stress files (.strn_, .strg_, .stnc_, .sttn_, .elss_)

*.strn_ - Nodal stress (the most-used output for cloud plots).

Pattern: <basename>.strn_<isub>.

Format:

2D ASCII: (I8, 4E20.12) → node_id, σxx, σyy, σxy, σvm.

3D ASCII: (6E20.12) → σxx, σyy, σzz, σxy, σyz, σxz (no node ID; ordering is implicit, one row per node).

Binary: unformatted stream.

Units: Pa (SI), or MPa (multiplied by 1.0e6 when *Key_Unit_System = 2).

Example (Test_Examples/2d_fem/fem_2d.strn_1):

1 -0.156417611316E+09 -0.521392037720E+09 0.132479407963E+09 0.517120498173E+09 2 -0.314927052617E+09 -0.131351166901E+09 -0.151570950392E+09 0.379456717788E+09 3 0.132437244468E+08 -0.434498039671E+09 0.491542972342E+08 0.449407109240E+09 4 -0.355598495381E+08 -0.374743859893E+09 0.100279409204E+09 0.398170199644E+09 5 -0.604493714661E+08 -0.352794869810E+09 0.137762121211E+09 0.404632332692E+09 6 -0.100352136399E+09 -0.312552949135E+09 0.169284080617E+09 0.402946449247E+09 7 -0.144585411303E+09 -0.264103676073E+09 0.187784543492E+09 0.397818122474E+09 8 -0.189543490576E+09 -0.211017942701E+09 0.192461730240E+09 0.389336335768E+09

*.strg_ - Gauss-point stress.

Format:

2D ASCII: (I8, 4E20.12) → gp_id, σxx, σyy, σxy, σvm.

3D ASCII: (I8, 7E20.12) → gp_id, σxx, σyy, σzz, σxy, σyz, σxz, σvm.

Binary: stream of (σxx, σyy, σxy, σvm) per Gauss point (2D only).

Units: Pa or MPa.

*.stnc_ - Nodal stress in cylindrical coordinates (3D only). Format: node_id, σrr, σθθ, σzz, σrθ, σθz, σrz, σvm.

*.sttn_ - Thermal-stress component only at each node. Enabled by *Key_Thermal_Stress = 1. Same column layout as .strn_.

*.elss_ - Element stress state flag (1-3 stress condition).

Format: one I2 integer per element. 0 = element does not satisfy the 1-3 condition; 1 = does.

Strain files (.sran_, .srac_)

*.sran_ - Nodal strain tensor.

Format: 2D = (I8, 4E20.12) → node_id, εxx, εyy, εxy, εvm. 3D = (I8, 7E20.12) (adds εzz, εyz, εxz).

Units: dimensionless.

*.srac_ - Nodal strain in cylindrical coordinates (3D). Columns: node_id, εrr, εθθ, εzz, εrθ, εθz, εrz, εvm.

Gauss-point files (.gcor_, .disg_, .damg_, .elgn_, .strg_)

*.gcor_ - Gauss-point coordinates.

Format: 2D = (E20.12) per Gauss point alternating X, Y, X, Y, …. Equivalently: (I8, 2E20.12) → gp_id, X, Y.

Units: m (SI) or mm (mm-ton-s).

*.disg_ - Gauss-point displacements. See the .disg_ entry above; same format.

*.damg_ - Per-Gauss-point damage factor.

Format: (E20.12) per Gauss point, one value per line.

*.elgn_ - Number of Gauss points per element.

Format: one I10 per element, one value per line.

*.strg_ - See "Stress files" above.

SIF / fracture-energy files (.sifs_, .sift_, .prst_, .enee)

*.sifs_ - Stress intensity factors (KI, KII) for both tips of every crack.

Pattern: <basename>.sifs_<isub>.

Format: One row per crack, (4E20.12) → KI_tip1, KII_tip1, KI_tip2, KII_tip2.

Units: Pa·√m (SI) or MPa·√m (mm-ton-s, divided by 1.0e-6 * sqrt(1000)).

Example (Test_Examples/2d_L_shaped_specimen/2d_L_shaped_specimen.sifs_1 — single crack):

0.000000000000E+00 0.000000000000E+00 0.100294273438E+07 0.438159774968E+05

Here crack 1 has KI₁ = 0, KII₁ = 0 at the first tip (a newly-formed tip), and KI₂ = 1.003e6 Pa·√m, KII₂ = 4.38e4 Pa·√m at the second (existing) tip.

*.sift_ - SIF time-history (NEWFTU-2026041702). Same format as .sifs_ but accumulated per-step for plotting.

*.prst_ - Propagation speed and SIFs at a specified tip (NEWFTU-2026060901). Format: per-tip values, see Save_SIFs_KI_and_KII.f90.

*.enee_ - Fracture-energy increment per substep (used in cohesive-crack modelling).

Crack coordinates (.crax/.cray/.craz, .crxo/.cryo, .cnox/.cnoy/.cnoz)

*.crax_ - 2D / 3D X-coordinates of crack polyline.

Format: One row per crack, (2000E20.12) → all X-coordinates of that crack's polyline on a single line. For 3D, the row count equals num_Crack; each row contains Each_Cr_Poi_Num(i) reals.

*.cray_ - Y-coordinates, same format as .crax_.

*.craz_ - Z-coordinates (3D only). Same format.

Example (Test_Examples/2d_L_shaped_specimen/2d_L_shaped_specimen.crax_1):

0.137028414927E-04 0.247500000000E-01

This row is the entire crack 1 polyline X-coordinates (2 points in this early step).

*.crxo_, .cryo_ - Original (un-edge-disposed) crack coordinates, written when the solver is restarted from a previous step.

*.cnox_, .cnoy_, .cnoz_ - 3D crack-meshed-node coordinates. Format: one row per crack, (50000E20.12) per coordinate direction. Used for visualisation of the crack surface in 3D.

Crack meshes (.cms1/.cms2/.cms3, .cmso, .cmap, .cape, .capf, .ctap)

*.cms1_, .cms2_, .cms3_ - Crack-mesh connectivity (3D crack surface triangulation).

Format: I10 integers, one per line. Index into the crack-node coordinate arrays (.cnox_, .cnoy_, .cnoz_). Triangles connect (cms1, cms2, cms3) node triples.

Indexing: 1-based integers.

*.cmso_ - Crack-mesh outline (the boundary polygon of the crack surface).

*.cmap_ - Crack aperture at each meshed crack node (3D). Format: (50000E20.12) per crack.

*.cape_ - Crack aperture at each calculation point (2D and 3D). Format: (2000E20.12) per crack.

Units: m (SI) or mm (mm-ton-s).

*.capf_ - Aperture at fluid-element calculation points (3D HF). Same per-crack layout as .cape_.

*.ctap_ - Crack tangential (shear) opening, used in cohesive and contact analyses.

Crack vertex and tangent files (.cvpx/.cvpy/.cvpz, .cvxx/.cvxy/.cvxz, ...)

These nine files describe the per-vertex coordinate frame of 3D cracks. Each is a per-crack row of (50000E20.12) reals, one file per coordinate direction.

*.cvpx_, .cvpy_, .cvpz_ - Vertex coordinates of the 3D crack outline.

*.cvxx_, .cvxy_, .cvxz_ - Local x-axis tangent vector at each vertex.

*.cvyx_, .cvyy_, .cvyz_ - Local y-axis tangent vector at each vertex.

*.cvzx_, .cvzy_, .cvzz_ - Local z-axis tangent vector at each vertex.

Crack calculation-point files (.apex/.apey, .cori, .cpre, .cvel, .cqua, .cohx/.cohy, .crrd)

*.apex_, .apey_ - Calculation-point coordinates (2D HF).

Format: per-crack row of (2000E20.12) reals. .apex_ = X, .apey_ = Y.

Units: m (SI) or mm (mm-ton-s).

*.cori_ - Calculation-point orientation angles (radians).

Format: per-crack row of (2000E20.12) reals.

*.cpre_ - Pore / fluid pressure at calculation points (HF only).

Format: per-crack row of (2000E20.12) reals. Units: Pa (SI), MPa (mm-ton-s).

*.cvel_ - Flow velocity at calculation points (HF). Units: m/s or mm/s.

*.cqua_ - Flow quantity (volumetric flow rate) at calculation points (HF). Units: m³/s.

*.cohx_, .cohy_ - Cohesive tractions (only for cohesive-crack analyses).

*.crrd_ - Crack radius for radial cracks. Enabled by *Key_Save_Crack_Radius = 1.

XFEM enrichment files (.ennd, .elty, .posi, .elts, .posh, .ennh, ...)

These describe the per-node / per-element XFEM enrichment topology. All are step-suffixed.

*.ennd_ - Enriched-node-type per crack.

Format: Num_Node rows × num_Crack columns in (200I10) format.

Type codes (2D): 0 = no enrichment, 1 = tip-enriched, 2 = Heaviside, 3 = junction, 4 = Heaviside-tip, 6 = hole-junction.

*.enns_ - Enriched-node-type for cross-interface analyses.

*.ennh_ - Enriched-node-type for hole analyses. Format: (200I10), columns = num_Hole.

*.ennj_ - Enriched-node-type for inclusion analyses. Columns = num_Inclusion.

*.elty_ - Element type per crack.

Format: Num_Elem rows × num_Crack columns in (200I10) format.

Type codes (2D): 0 = none; 1 = tip; 2 = fully cracked (no kink); 3 = fully cracked (with kink); 4 = junction; 5 = complex junction; 6 = crack-hole junction.

Type codes (3D): 0 = none; 1 = tip; 2 = Heaviside.

*.elts_ - Element type for cross-interface.

*.elth_ - Element type for holes. Format: (200I10), columns = num_Hole.

*.eltj_ - Element type for inclusions.

Example (Test_Examples/2d_L_shaped_specimen/2d_L_shaped_specimen.elty_1 — first 10 rows):

2 0 0 0 0 0 0 0 0 0

Each value is the integer type code for that element w.r.t. crack 1 (column-wise, since this is a single-crack problem).

*.posi_, .poss_, .posh_, .posj_ - Signed-distance / position signs (per node per feature). Same (200I10) row layout as .ennd_. Values are ±1 (side of the discontinuity the node lies on).

*.njel_ - Crack-node to junction-element association. Integer pairs.

*.nods_ - Node-to-host-element mapping for cross-interface problems.

Crack-tip and baseline files (.celt, .celv, .celj, .celc, .ctty, .blab, .blvx/.blvy/.blvz, .tere)

These files describe the local geometry of enriched elements around the crack tip.

*.celt_ - Tip-element coordinates per element.

*.celv_ - Vertex coordinates per element.

*.celj_ - Junction coordinates per element per crack.

*.celc_ - Element crack-intersection coordinates.

*.ctty_ - Crack-tip type per crack.

*.blab_ - Crack baseline vectors. Format: 6 values per element (two endpoint coordinates X, Y, Z).

*.blvx_, .blvy_, .blvz_ - Baseline direction-vector components (one file per axis).

*.tere_ - Tip-enriched node element number. Format: enriched_node_number, crack_id.

Crack-node S1 vector files (.cndx/.cndy/.cndz)

*.cndx_, .cndy_, .cndz_ - Crack-node S1 vector components used in the CFCP-2 crack-propagation criterion (maximum principal tensile stress). Enabled when *CFCP = 2.

Hole and inclusion files (.hlcr, .ehcr, .jzcr, .jzpx/.jzpy)

Holes and inclusions have no step suffix — written once per analysis.

*.hlcr - Circular hole coordinates.

Format: num_Circ_Hole rows, (3E20.12) per row → x_center, y_center, z_center.

*.ehcr - Elliptical hole parameters.

Format: num_Ellip_Hole rows, (5E20.12) per row → x_c, y_c, a, b, θ (center, semi-axes, rotation angle).

*.jzcr - Circular inclusion coordinates.

Format: num_Circ_Incls rows, (3E20.12) per row → x, y, r (center and radius).

*.jzpx, .jzpy - Polygonal inclusion vertex coordinates (X and Y). Format: per-inclusion rows of (2000E20.12).

Cross-interface files (.cscr)

*.cscr - Cross-interface point coordinates.

Format: per-cross row of (2E20.12) → x, y.

Natural-fracture files (.nfcx/.nfcy/.nfcz, .ncrx/.ncry)

*.nfcx, .nfcy, .nfcz - Natural-fracture vertex coordinates (3D). Format: per-fracture row of (50000E20.12) per axis.

*.ncrx, .ncry - Natural-crack endpoint coordinates (2D). Format: x1, x2 comma-separated per crack.

Energy history files (.ener, .edye, .edtm, .edap)

*.ener - Energy balance per load step. Append-mode — written once per step.

Header (written at iter = 1):
# iter Elastic_Strain_Energy Fracture_Energy External_Work Residual_Energy Normalized_Residual Crack_Propagation_Length

Data rows ((I10, 6(2X, E20.12))): iter, Elastic_Strain_Energy, Fracture_Energy, External_Work, Residual_Energy, Normalized_Residual_Energy, Crack_Propagation_Length

Units: J (SI), or mJ (mm-ton-s); length in m or mm.

Example (Test_Examples/2d_L_shaped_specimen/2d_L_shaped_specimen.ener):

# iter Elastic_Strain_Energy Fracture_Energy External_Work Residual_Energy Normalized_Residual Crack_Propagation_Length 1 0.472931017820E+01 -0.129866029815E-15 0.473748321243E+01 0.817303423107E-02 0.172518484279E+00 -0.346944695195E-17 2 0.403905163275E+01 0.935783374928E+00 0.498766375932E+01 0.128287516428E-01 0.257209632844E+00 0.250000002500E-01 3 0.349579005177E+01 0.187156673676E+01 0.541280434455E+01 0.454475560179E-01 0.839630496966E+00 0.500000001500E-01 4 0.299507968076E+01 0.280735009297E+01 0.588459158372E+01 0.821618099953E-01 0.139621941177E+01 0.749999999000E-01 5 0.252293261486E+01 0.374313345230E+01 0.635674090155E+01 0.906748343931E-01 0.142643590163E+01 0.999999997333E-01 6 0.200212858936E+01 0.467891680596E+01 0.682556546132E+01 0.144520066004E+00 0.211733470029E+01 0.124999999415E+00 7 0.155959488881E+01 0.561470017729E+01 0.732121007053E+01 0.146915004425E+00 0.200670385100E+01 0.149999999569E+00 8 0.114477972662E+01 0.655048354286E+01 0.788939019863E+01 0.194126929148E+00 0.246060752809E+01 0.174999999569E+00

Reading: at step 8, the elastic-strain energy has dropped to 1.14 J while fracture-energy has accumulated to 6.55 J, with crack propagating a total of 0.175 m.

*.edye - Explicit-dynamics energy history.

Header: # iter time kinetic_energy (T) internal_energy (U) total_energy (T+U) external_Work (W).

Data: iter, time, T, U, T+U, W ((I10, 5E20.12)).

*.edtm - Explicit-dynamics time history. Format: (I10, E20.12) → iter, time.

*.edap - Explicit-dynamics max/min/avg aperture per crack (3D). Format: (E20.12, I10, 3E20.12) → time, crack_id, max_aperture, min_aperture, avg_aperture.

Crack length history (.dcrl, .dprl, .idtm, .iite, .ilth, .ipre)

*.dcrl - Total crack length history (dynamic 2D).

Header: iter c_Time(s) Crack_1_Length(m).

Data: (I10, 2E20.12) → iter, time, total_crack_length.

*.dprl - Crack propagation length history (the incremental growth, excluding the initial crack length).

Format: same as .dcrl. Use this for the "growth length" vs energy curves.

Dynamic files (.idtm, .edtm, .dcrl, .dprl)

Implicit-dynamics and explicit-dynamics share several time-history files:

*.idtm - Implicit-dynamics time history. Format: iter, time ((I10, E20.12)).

The other dynamic files (.edtm, .dcrl, .dprl) are covered in their respective sections.

Lumped mass files (.lpmf_, .lpmx_, .lpma_)

*.lpmf_ - Lumped mass at each node from the standard FEM mass matrix.

Format: one (E20.12) per node.

*.lpmx_ - Lumped mass from the enriched (XFEM) mass matrix. Zero for non-enriched nodes.

*.lpma_ - Superposition (FEM + enriched) lumped mass at each node.

Hydraulic-fracturing output files (.hftm, .injp, .wbfp, .wbpt, .ihft, .icpt, .icpt_LS, .icpt_CT)

*.hftm - HF analysis time-history log. Append-mode.

Header (at first call (1, 1, 1)):
imf | ifra | total_ter| time

Data: (3I10, 1F18.5) → imf, ifra, Counter_Iter, c_Time.

Cleared at the start of each new analysis run by deleting the file (lines 36-40 of Save_HF_time.f90).

*.injp - HF injection-pressure history. Append-mode.

Format: (2E20.12) per row → time, pressure.

Units: seconds and Pa (SI), or seconds and MPa (mm-ton-s).

*.wbfp - Wellbore fracturing path (XYZ coordinates of wellbore stages).

Format: 3 reals per wellbore point (XYZ), per stage.

*.wbpt - Wellbore/stage/proppant pressure vs time.

Format: 5 columns → i_WB, i_Stage, i_Prop, time, pressure.

*.ihft - HF time per fracture step.

Format: per-step (F12.5) row (only positive entries written).

Header: first row is the string HF time of each time step.

*.icpt - CPU time per step (total wall time).

*.icpt_LS - CPU time spent in the linear solver per step.

*.icpt_CT - CPU time spent in cohesive/contact computations per step.

*.iite - Number of iterations per fracture step.

*.ilth - Crack-1 length per fracture step.

*.ipre - Maximum pressure in crack 1 per fracture step.

Proppant output files (.ccon_, .pokf_, .cond_, .wpnp_, .epcr_, .Saved_Filename)

All proppant files are enabled by *Key_Propp_Trans = 1.

*.ccon_ - Proppant concentration at calculation points.

*.pokf_ - Proppant permeability (kf = Cf / w, concentration divided by aperture).

*.cond_ - Proppant conductivity.

*.wpnp_ - Propped aperture at zero closure.

*.epcr_ - Element proppant coordinates.

Format: per-element row (I8, 4E20.12) → element_id, x, y, z, w (centroid X, Y, Z and proppant mass w).

Only elements with Elem_Proppant_Coor(i,1) = 1 are written.

*.Saved_Filename - Flow rate at a specific wellbore point. The filename is taken from a keyword-supplied name (not auto-generated).

Format: ifra, time, flow_Q per row.

Contact, cohesive and element-state files (.elcs_, .elco_, .elss_, .kiel_)

*.elcs_ - Contact state per element. Integer per element:

0 = open

1 = stick

2 = slip

*.elco_ - Cohesive state per element. Integer per element: 0 = inactive, 1 = active.

*.elss_ - Element 1-3 stress-condition flag. Integer per element: 0 = not satisfied, 1 = satisfied. See .elss_ in Stress files above.

*.kiel_ - Killed (broken / deactivated) element IDs.

Format: one I10 integer per line; accumulated from all prior steps plus current step.

DOF / surface-load force files (.fxdf_, .fydf_, .fzdf_, .fxsl_, .fysl_, .fzsl_)

*.fxdf_ - X-DOF internal force vector.

Format: one (E20.12) per node.

*.fydf_ - Y-DOF internal force.

*.fzdf_ - Z-DOF internal force (3D only).

*.fxsl__ - Surface-load X-component per surface load iSL. Same format.

*.fysl__ - Surface-load Y-component per iSL.

*.fzsl__ - Surface-load Z-component per iSL (3D only).

Stiffness-matrix files (.skxf, .csrn_, .csra_, .csrj_, .csri_)

*.skxf - XFEM element stiffness matrices (binary). Each XFEM element's flattened K-matrix is written as a binary record. Async-write mode is used for performance.

*.csrn_ - CSR matrix dimensions.

Format: 3 lines, each (I0):
K_CSR_NNZ num_FreeD XFEM_Start_DOF

*.csra_ - CSR value array (K_CSR_aa). Format: one (E25.16E3) value per line, K_CSR_NNZ rows.

*.csrj_ - CSR column-index array (K_CSR_ja). Format: one (I0) value per line, K_CSR_NNZ rows.

*.csri_ - CSR row-pointer array (K_CSR_ia). Format: one (I0) value per line, num_FreeD + 1 rows.

These four CSR files together define the assembled CSR sparse stiffness matrix. They can be re-loaded by external linear-system codes for further processing.

3D fluid-crack files (.fenx/.feny/.fenz, .fnnx/.fnny/.fnnz, .fnux/.fnuy/.fnuz, .fnlx/.fnly/.fnlz, .fexx/.fexy/.fexz/.feyx/.feyy/.feyz/.fezx/.fezy/.fezz, .cpfn_, .cpno_, .ccpx/.ccpy/.ccpz, .cnlx/.cnly/.cnlz, .cmse_)

3D hydraulic-fracturing uses fluid elements embedded in the crack surface. All files here are step-suffixed and use (E20.12) per row or (50000E20.12) per crack.

*.fenx_, .feny_, .fenz_ - Fluid-element normal vectors (per-element).

*.fnnx_, .fnny_, .fnnz_ - Fluid-node normal vectors (per-node).

*.fnux_, .fnuy_, .fnuz_ - Up-face displacement vectors at crack nodes.

*.fnlx_, .fnly_, .fnlz_ - Low-face displacement vectors at crack nodes.

*.fexx_, .fexy_, .fexz_, .feyx_, .feyy_, .feyz_, .fezx_, .fezy_, .fezz_ - Fluid-element local-coordinate axes (x, y, z basis at each element centroid).

*.cpfn_ - Fluid node count per crack (one integer per crack).

*.cpno_ - Fluid node numbers per crack.

*.ccpx_, .ccpy_, .ccpz_ - Fluid-node coordinates (X, Y, Z).

*.cnlx_, .cnly_, .cnlz_ - Crack-node local coordinates (in the fluid-element frame).

*.cmse_ - Element containing each crack node.

Miscellaneous files (.fraz, .seed, .post, .fdcu, .fccu, .rbco_, .fdvl, .ecfv, .sccx/.sccy/.sccz, .scdx/.scdy/.scdz)

*.fraz - Fracture-zone bounding box.

Format 2D: F12.5 × 4 → min_X, max_X, min_Y, max_Y.

Format 3D: F12.5 × 6 → min_X, max_X, min_Y, max_Y, min_Z, max_Z.

*.seed - Random-number seed (used by stochastic analyses). Format: plain text I11.

*.post - Header for the legacy MATLAB post-processor.

Format: single line with six values: Key_Analysis_Type, Key_TipEnrich, Key_Data_Format, Key_Heaviside_Value, Key_Hole_Value, Ave_Elem_L

*.fdcu - Force-displacement curve at a specified node.

Header: node | isub | lambda | dis_of_node.

Data: node_id, isub, λ, displacement.

*.fccu - Force-COD (crack-opening-displacement) curve.

Header: crack | isub | lambda | COD.

*.rbco_ - Rigid-ball (circle) coordinates (for rigid-ball contact problems). Format: x, y, radius per ball.

*.fdvl_ - Fluid-velocity per-node (for HF post-processing). Format: 2D = node_id, vx, vy; 3D = node_id, vx, vy, vz.

*.ecfv_ - Element-centroid field value (used by some HF post-processors).

*.sccx_, .sccy_ - 2D stress-corrosion-cracking X / Y coordinates.

*.scdx_, .scdy_ - 2D stress-corrosion displacement X / Y.

Console / log files (PhiPsi_Console_Window.log, current_folder.dat)

*PhiPsi_Console_Window.log - Console-window text capture. Written next to the executable when *Key_Save_Window_Log = 1 (or equivalent).

*current_folder.dat - Single-line text file containing the last Work_Directory. Used by PPView to remember the most-recent folder. Written at <PhiPsi current directory>\current_folder.dat and <PhiPsi current directory>\python_tools\current_folder.dat.

PPView file-reading map

PPView (PPView/PPView/) consumes the output files above and renders them as cloud plots, curves, vectors, and 3D meshes. This section lists the file-to-feature mapping discovered in pp_utilities.py, pp_plotting.py, and child_window.py.

Cloud plot / contour rendering

PPView's cloud-plot window reads displacement / stress / strain fields and renders them as a colour-mapped surface over the mesh.

Feature Files read Columns / fields used

Displacement magnitude *.disn_ node_id, Ux, Uy (2D comma) or Ux, Uy, Uz (3D space). Magnitude = sqrt(Ux² + Uy² + …).

Displacement X / Y / Z *.disn_ single component.

Stress σxx / σyy / σxy / σvm *.strn_ 2D = 4 stress columns; 3D = 6 stress columns.

Stress σzz / σyz / σxz *.strn_ 3D-only columns.

Cylindrical stress σrr / σθθ / σrθ *.stnc_ 3D-only columns.

Strain *.sran_ 2D = 4 strain columns; 3D = 7.

Stress / strain at Gauss points *.strg_, *.disg_ one row per Gauss point.

Enriched-node indicator *.ennd_, *.elty_ integer per node / element.

Enriched-DOF displacement *.dien_ zero for non-enriched.

Full cloud (any field) *.vtk SCALARS fields written by Save_vtk_file.f90 (stress, displacement, material ID, etc.).

Crack displacement (3D) *.fnux_, *.fnlx_ up- and low-face displacement at crack nodes.

Curve plot / line chart rendering

The curve-plot window (e.g. Plot_Curve_Settings_Window in child_window.py) reads time-history files and plots one column versus another.

Feature Files read X-axis options Y-axis options

Energy vs step / growth length *.ener iter (step #), or Crack_Propagation_Length (col 7) Elastic_Strain_Energy, Fracture_Energy, External_Work, Residual_Energy, Normalized_Residual_Energy

Explicit-dynamics energy *.edye time, iter T, U, T+U, W

SIF history *.sifs_ (NEWFTU-2026041702 stack) step # KI_tip1, KII_tip1, KI_tip2, KII_tip2

Crack length / growth *.dcrl, *.dprl iter, time Crack_1_Length

Displacement at a node *.disn_ node index Ux, Uy

Velocity / acceleration at a node *.veln_, *.acln_ (NEWFTU-2026041702) node index single component

Lumped-mass *.lpmf_, *.lpma_ node index mass

Vector plot / arrow rendering

The vector-plot window reads vector-valued fields and renders them as 3D arrows (via PyVista).

Feature Files read Columns / fields used

Displacement arrows *.disn_ (Ux, Uy) (2D) or (Ux, Uy, Uz) (3D).

Velocity arrows *.veln_ as above.

Block / baseline vectors *.blvx_, *.blvy_, *.blvz_ one axis per file.

Fluid-element local axes *.fexx_ … *.fezz_ nine-component basis.

Original boundary forces *.focx, *.focy, *.focz (input) node_id, force_value.

Crack visualization (2D and 3D)

PPView's crack-overlay window reads crack geometry files and overlays them on the deformed mesh.

Feature Files read Notes

2D crack polyline *.crax_, *.cray_ per-crack rows of X, Y coordinates.

2D crack aperture *.cape_ aperture colour map.

2D crack orientation *.cori_ used for tip-extension direction.

2D enriched element types *.elty_, *.ennd_ colour-code tip / Heaviside / junction elements.

2D calc-point overlay *.apex_, *.apey_ HF analysis pressure / aperture.

3D crack surface mesh *.cnox_, *.cnoy_, *.cnoz_ + *.cms1_, *.cms2_, *.cms3_ triangle vertex coords + triangle connectivity.

3D crack aperture *.cmap_, *.cape_ colour map on the crack surface.

3D crack outline *.cmso_ boundary polygon.

3D natural fractures *.nfcx, *.nfcy, *.nfcz read once.

Clipped crack variants *.cnxc_, *.cnyc_, *.cnzc_, *.cmc1_ … when the model is sliced by a plane.

Crack-aperture history *.cape_ for i = 1, 2, …, n frame-by-frame aperture animation.

Animation playback

PPView generates GIF / PNG animations by reading sequential step-suffixed files.

Source Behavior

<name>_NNNNN.vtk sequence Loaded into PyVista; each frame is a vtkUnstructuredGrid rendered in turn.

<name>_.disn_ / .strn_ / .crax_ etc. sequence Each frame's results are mapped onto the same .node / .elem mesh, then exported as PNG and stitched into a GIF (WorkerThread_Generate_Animation in pp_utilities.py).

3D crack frame *.crax_ / *.cray_ / *.craz_ for 2D; *.cms1/2/3_ for 3D.

Animation parameters (animation_interval, gif_scale_factor) are configured in child_window.py's animation tab.

Data format examples

The next four sections show real excerpts from Test_Examples/. They are intentionally short (5–10 lines per file) so the manual stays readable; the corresponding full files in the repository are far larger.

Example A — 2D simple FEM (Test_Examples/2d_fem)

A quasi-static plane-stress FEM run on a square plate.

2d_fem.kpp — the keyword input file:

% Working directory. *Work_Directory X:\PhiPsi_Project\Test_Examples\2d_fem % Filename of input files. *Filename fem_2d % Quasi-static analysis. *Key_Analysis_Type 1 % Plane stress. *Key_Type_2D 1 % MUMPS solver. *Key_SLOE 6 % One sub-step. *Num_Substeps 1 % Material(1-E,2-v,3-density,4-thick,5-St,6-KIc,7-Sc,8-20(blank)) *Material_Para_1 70.0e9,0.3,2700.0,1.0,1.0e6,1.0e6,100.0e6,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0 % Save VTK files. *Key_Save_vtk 1

fem_2d.node — 2D node coordinates (X Y):

0.50000000E-01 0.00000000E+00 -0.40000000E-01 0.30000000E-01 0.49610478E-01 0.62290027E-02 0.48447981E-01 0.12360952E-01 0.46530622E-01 0.18300307E-01 0.43888275E-01 0.23954527E-01 0.40562109E-01 0.29235514E-01 0.36603951E-01 0.34060986E-01 0.32075470E-01 0.38355759E-01 0.27047226E-01 0.42052914E-01

fem_2d.elem — 4-node quad elements (n1 n2 n3 n4 mat):

1. 3. 81. 62. 1. 3. 4. 100. 81. 1. 4. 5. 119. 100. 1. 5. 6. 138. 119. 1. 6. 7. 157. 138. 1. 7. 8. 176. 157. 1. 8. 9. 195. 176. 1. 9. 10. 214. 195. 1. 10. 11. 233. 214. 1. 11. 12. 252. 233. 1.

fem_2d.boux — left-edge nodes fixed in X:

1. 42. 62. 63. 64. 65. 66. 67. 68. 69.

fem_2d.focy — nodal Y-forces (downward traction on the top edge):

22. 0.22500000E+05 462. 0.22500000E+05 482. 0.45000000E+05 483. 0.45000000E+05 484. 0.45000000E+05 485. 0.45000000E+05 486. 0.45000000E+05 487. 0.45000000E+05 488. 0.45000000E+05 489. 0.45000000E+05

fem_2d.disn_1 — output: nodal displacements (node_id, Ux, Uy, comma-separated):

1, 0.000000000000E+00, 0.000000000000E+00 2, 0.309792344217E-03, 0.200022243102E-02 3, 0.306508276247E-04, -0.422207813393E-04 4, 0.661986220995E-04, -0.714963121533E-04 5, 0.116443200093E-03, -0.937367347085E-04 6, 0.181700145801E-03, -0.103665261266E-03 7, 0.259776862462E-03, -0.974530658974E-04 8, 0.347292854805E-03, -0.718664920552E-04 9, 0.440084114000E-03, -0.246253768389E-04 10, 0.533547239550E-03, 0.455736716968E-04

fem_2d.strn_1 — output: nodal stresses (node_id, σxx, σyy, σxy, σvm):

1 -0.156417611316E+09 -0.521392037720E+09 0.132479407963E+09 0.517120498173E+09 2 -0.314927052617E+09 -0.131351166901E+09 -0.151570950392E+09 0.379456717788E+09 3 0.132437244468E+08 -0.434498039671E+09 0.491542972342E+08 0.449407109240E+09 4 -0.355598495381E+08 -0.374743859893E+09 0.100279409204E+09 0.398170199644E+09 5 -0.604493714661E+08 -0.352794869810E+09 0.137762121211E+09 0.404632332692E+09 6 -0.100352136399E+09 -0.312552949135E+09 0.169284080617E+09 0.402946449247E+09 7 -0.144585411303E+09 -0.264103676073E+09 0.187784543492E+09 0.397818122474E+09 8 -0.189543490576E+09 -0.211017942701E+09 0.192461730240E+09 0.389336335768E+09

fem_2d_00001.vtk — output: ParaView-compatible VTK snapshot (header + first POINTS):

# vtk DataFile Version 4.0 X:\PhiPsi_Project\Test_Examples\2d_fem\fem_2d - results from increment 00001 ASCII DATASET UNSTRUCTURED_GRID POINTS 861 double 0.050000 0.000000 0.000000 -0.040000 0.030000 0.000000 0.049610 0.006229 0.000000 0.048448 0.012361 0.000000 0.046531 0.018300 0.000000 0.043888 0.023955 0.000000 0.040562 0.029236 0.000000 0.036604 0.034061 0.000000 0.032075 0.038356 0.000000 0.027047 0.042053 0.000000

Example B — 2D crack propagation (Test_Examples/2d_L_shaped_specimen)

A quasi-static plane-stress L-shaped panel with an initial crack propagating over 8 sub-steps. This example exercises nearly every output format.

2d_L_shaped_specimen.kpp (key lines):

*Work_Directory X:\PhiPsi_Project\Test_Examples\2d_L_shaped_specimen *Filename 2d_L_shaped_specimen *Key_Analysis_Type 1 % Quasi-static. *Key_Type_2D 1 % Plane stress. *Key_SLOE 6 % MUMPS solver. *Num_Substeps 8 % 8 propagation steps. *Num_Crack 1 *CRACK2D_Coor_1 0.137028414927E-04,0.247500000000E-01 *Material_Para_1 20.0e9,0.3,2000.0,1.0,0.1e6,1.0e6,100.0e6,... *Key_Save_vtk 1

2d_L_shaped_specimen.elem — first 10 rows:

1. 60. 61. 3. 1. 60. 59. 75. 61. 1. 59. 58. 89. 75. 1. 58. 57. 103. 89. 1. 57. 56. 117. 103. 1. 56. 55. 131. 117. 1. 55. 54. 145. 131. 1. 54. 53. 159. 145. 1. 53. 52. 173. 159. 1. 52. 51. 187. 173. 1.

2d_L_shaped_specimen.focy — applied Y-forces:

512. 0.20000000E+04 741. 0.10000000E+04 742. 0.20000000E+04 743. 0.20000000E+04 744. 0.20000000E+04

2d_L_shaped_specimen.sifs_1 — SIFs at step 1 (one crack, two tips):

0.000000000000E+00 0.000000000000E+00 0.100294273438E+07 0.438159774968E+05

2d_L_shaped_specimen.crax_1 — crack-1 X-coordinates (polyline row):

0.137028414927E-04 0.247500000000E-01

2d_L_shaped_specimen.elty_1 — element type per crack (first 10 elements):

2 0 0 0 0 0 0 0 0 0

2d_L_shaped_specimen.ener — full 8-step energy balance:

# iter Elastic_Strain_Energy Fracture_Energy External_Work Residual_Energy Normalized_Residual Crack_Propagation_Length 1 0.472931017820E+01 -0.129866029815E-15 0.473748321243E+01 0.817303423107E-02 0.172518484279E+00 -0.346944695195E-17 2 0.403905163275E+01 0.935783374928E+00 0.498766375932E+01 0.128287516428E-01 0.257209632844E+00 0.250000002500E-01 3 0.349579005177E+01 0.187156673676E+01 0.541280434455E+01 0.454475560179E-01 0.839630496966E+00 0.500000001500E-01 4 0.299507968076E+01 0.280735009297E+01 0.588459158372E+01 0.821618099953E-01 0.139621941177E+01 0.749999999000E-01 5 0.252293261486E+01 0.374313345230E+01 0.635674090155E+01 0.906748343931E-01 0.142643590163E+01 0.999999997333E-01 6 0.200212858936E+01 0.467891680596E+01 0.682556546132E+01 0.144520066004E+00 0.211733470029E+01 0.124999999415E+00 7 0.155959488881E+01 0.561470017729E+01 0.732121007053E+01 0.146915004425E+00 0.200670385100E+01 0.149999999569E+00 8 0.114477972662E+01 0.655048354286E+01 0.788939019863E+01 0.194126929148E+00 0.246060752809E+01 0.174999999569E+00

Example C — 3D uniaxial tension (Test_Examples/3d_uniaxial_tension)

A 3D XFEM run on a rectangular block with one penny-shaped crack.

3d_uniaxial_tension.kpp (key lines):

*Work_Directory X:\PhiPsi_Project\Test_Examples\3d_uniaxial_tension *Filename 3d_uniaxial_tension *Key_Dimension 3 % 3D problem. *Key_Analysis_Type 1 % Quasi-static. *Num_Crack 1 *CRACK3D_CIR_COOR_1 5.5,5.5,7.5,0,0,1,2.5 *Material_Para_1 20.0e9,0.3,2000.0,1.0,0.1e6,1.0e6,100.0e6,... *Key_Save_vtk 1

3d_uniaxial_tension.node — 3D node coordinates (X Y Z):

0.00000000E+00 0.00000000E+00 0.00000000E+00 0.11000000E+02 0.00000000E+00 0.00000000E+00 0.36666667E+00 0.00000000E+00 0.00000000E+00 0.73333333E+00 0.00000000E+00 0.00000000E+00 0.11000000E+01 0.00000000E+00 0.00000000E+00 0.14666667E+01 0.00000000E+00 0.00000000E+00 0.18333333E+01 0.00000000E+00 0.00000000E+00 0.22000000E+01 0.00000000E+00 0.00000000E+00

3d_uniaxial_tension.elem — 8-node hexahedra (n1 n2 n3 n4 n5 n6 n7 n8 mat):

1. 3. 121. 120. 1072. 1073. 6723. 4722. 1. 3. 4. 150. 121. 1073. 1113. 7883. 6723. 1. 4. 5. 179. 150. 1113. 1153. 9043. 7883. 1. 5. 6. 208. 179. 1153. 1193. 10203. 9043. 1. 6. 7. 237. 208. 1193. 1233. 11363. 10203. 1. 7. 8. 266. 237. 1233. 1273. 12523. 11363. 1. 8. 9. 295. 266. 1273. 1313. 13683. 12523. 1. 9. 10. 324. 295. 1273. 1353. 14843. 13683. 1.

3d_uniaxial_tension.focz — applied Z-forces:

962. 0.33586629E+06 1003. 0.33586629E+06 1004. 0.67173257E+06 1005. 0.67173257E+06 1006. 0.67173257E+06

3d_uniaxial_tension.disn_1 — output: 3D nodal displacements (node_id Ux Uy Uz, space-separated):

1 0.000000000000E+00 0.000000000000E+00 0.000000000000E+00 2 -0.158000824552E-02 0.000000000000E+00 0.000000000000E+00 3 -0.599530622114E-04 -0.198353082554E-05 0.000000000000E+00 4 -0.119662125493E-03 -0.473063658899E-05 0.000000000000E+00 5 -0.178898410344E-03 -0.864250808527E-05 0.000000000000E+00 6 -0.237351373110E-03 -0.138088347514E-04 0.000000000000E+00 7 -0.294744765137E-03 -0.201261481292E-04 0.000000000000E+00 8 -0.350861002901E-03 -0.273768250648E-04 0.000000000000E+00 9 -0.405543687855E-03 -0.352738546285E-04 0.000000000000E+00 10 -0.458697601816E-03 -0.434876069018E-04 0.000000000000E+00

3d_uniaxial_tension_00001.vtk — output: 3D VTK snapshot:

# vtk DataFile Version 4.0 X:\PhiPsi_Project\Test_Examples\3d_uniaxial_tension\3d_uniaxial_tension - results from increment 00001 ASCII DATASET UNSTRUCTURED_GRID POINTS 40362 double 0.000000 0.000000 0.000000 11.000000 0.000000 0.000000 0.366667 0.000000 0.000000 0.733333 0.000000 0.000000 1.100000 0.000000 0.000000 ... CELLS 35152 281216 8 0 2 119 118 1071 1072 6722 4721 ... CELL_TYPES 35152 12 12 ... POINT_DATA 40362 VECTORS Displacement double 0.000000E+00 0.000000E+00 0.000000E+00 -1.580008E-03 0.000000E+00 0.000000E+00 -5.995306E-05 -1.983531E-06 0.000000E+00 ...

Example D — 3D hydraulic fracturing (Test_Examples/3d_hf_toughness_dominated)

A toughness-dominated 3D HF simulation; this example exercises the entire HF output stack.

3d_hf_toughness_dominated.kpp (key lines):

*Work_Directory X:\PhiPsi_Project\Test_Examples\3d_hf_toughness_dominated *Filename 3d_hf_toughness_dominated *Key_Dimension 3 *Key_Analysis_Type 3 % Hydraulic fracturing. *Num_Crack 1 *CRACK3D_CIR_COOR_1 ... *INJECTION_T_STAGES_WELLBORES_1_1 *INJECTION_P_STAGES_WELLBORES_1_1 ...

3d_hf_toughness_dominated.hftm — HF macro/fracture time history (append mode):

imf | ifra | total_ter| time 1 1 1 0.00000 1 1 2 0.05000 1 1 3 0.10000 1 1 4 0.15000 1 2 5 0.20000 1 2 6 0.25000 2 3 7 0.30000

3d_hf_toughness_dominated.injp — injection-pressure history:

0.000000000000E+00 0.500000000000E+07 0.500000000000E-01 0.510000000000E+07 0.100000000000E+00 0.520000000000E+07 0.150000000000E+00 0.530000000000E+07 0.200000000000E+00 0.540000000000E+07

3d_hf_toughness_dominated.wbpt — wellbore / stage / proppant pressure vs time:

i_WB | i_Stage | i_Prop | Time (s) | Pressure (Pa) 1 1 1 0.00000 0.5000000E+07 1 1 1 0.05000 0.5100000E+07 1 1 1 0.10000 0.5200000E+07 1 1 1 0.15000 0.5300000E+07 1 1 1 0.20000 0.5400000E+07

3d_hf_toughness_dominated.cms1_1, cms2_1, cms3_1 — crack-mesh triangle connectivity (first 5 triangles):

1 2 3 4 5 ...

(Each value is a 1-based index into the corresponding .cnox_1, .cnoy_1, .cnoz_1 arrays.)

3d_hf_toughness_dominated.cmap_1 — crack-mesh aperture (per-crack row):

0.000000000000E+00 0.000000000000E+00 0.000000000000E+00 ... (50000 values per line, one row per crack)

3d_hf_toughness_dominated.cape_1 — crack calculation-point aperture:

0.000000000000E+00 0.000000000000E+00 0.000000000000E+00 ... (2000 values per line, one row per crack)

3d_hf_toughness_dominated.fenx_1, feny_1, fenz_1 — fluid-element normal vectors:

0.000000000000E+00 0.000000000000E+00 0.000000000000E+00 1.000000000000E+00 0.000000000000E+00 0.000000000000E+00 0.000000000000E+00 1.000000000000E+00 ...

Quick-reference summary tables

All input-file summary table

Extension 2D 3D Columns Required Reader Purpose

.kpp Y Y text Yes PhiPsi_Read_Input.F90 Keyword / control input

.node Y Y 2 / 3 Yes Read_Geo*.F90 Node coordinates

.elem Y Y 5 / 9 Yes Read_Geo*.F90 Element connectivity + material

.boux Y Y 1 No Read_Geo*.F90 X-DOF zero constraint

.bouy Y Y 1 No Read_Geo*.F90 Y-DOF zero constraint

.bouz – Y 1 No Read_Geo_3D.F90 Z-DOF zero constraint

.buxn Y Y 2 No Read_Geo*.F90 Non-zero prescribed X disp.

.buyn Y Y 2 No Read_Geo*.F90 Non-zero prescribed Y disp.

.buzn – Y 2 No Read_Geo_3D.F90 Non-zero prescribed Z disp.

.focx Y Y 2 No Read_Geo*.F90 X-direction point load

.focy Y Y 2 No Read_Geo*.F90 Y-direction point load

.focz – Y 2 No Read_Geo_3D.F90 Z-direction point load

.ivex / .ivey Y Y 2 No Read_Geo*.F90 Initial velocity X / Y

.ivez – Y 2 No Read_Geo_3D.F90 Initial velocity Z

.iacx / .iacy Y Y 2 No Read_Geo*.F90 Initial acceleration X / Y

.iacz – Y 2 No Read_Geo_3D.F90 Initial acceleration Z

.idpx / .idpy – Y 2 No Read_Geo_3D.F90 Initial displacement X / Y (3D only)

.idpz – Y 2 No Read_Geo_3D.F90 Initial displacement Z

.dofx / .dofy Y Y 2 No Read_Geo*.F90 Multi-point-constraint coupling sets

.fbvl / .fbqn / .fbiv Y – 2 No Src_Field_Prob/ Field-problem boundary value / flux / initial

.bhpc Y – 2 Conditional Read_Geo*.F90 Wellbore pressure curve (Key_Analysis_Type 16 / 17)

.eqnl – Y 1 Conditional Read_Geo_3D.F90 Earthquake acceleration nodes (EQ_Ac_nodes_list_method = 2)

.boud / .focd Y Y text No (PPView metadata) PPView/Open_Read_Update_kppFile.py PPView geometry metadata

All output-file summary table

Extension Step suffix Format Purpose Enabling keyword

_<isub5>.vtk Yes (zero-padded 5) ASCII Main solution snapshot (ParaView) *Key_Save_vtk = 1

_CRACK_<isub5>.vtk Yes ASCII Crack geometry snapshot *Key_Save_vtk = 1

.disp_ Yes ASCII / Binary Global DOF displacement vector always (unless *Key_Save_Nothing = 1)

.disn_ Yes ASCII / Binary Nodal displacement (Ux, Uy[, Uz]) always

.dien_ Yes ASCII / Binary Enriched-DOF displacement always

.edei_ Yes ASCII Enriched-DOF index map always

.disg_ Yes ASCII Gauss-point displacement always

.dipc_ / .dinc_ Yes ASCII / Binary Cylindrical-coord displacement *Key_CoorSys = 2

.veln_ / .acln_ Yes ASCII Per-node velocity / acceleration dynamic analyses only

.strn_ Yes ASCII / Binary Nodal stress tensor always

.strg_ Yes ASCII / Binary Gauss-point stress tensor always

.stnc_ Yes ASCII Nodal stress in cylindrical *Key_CoorSys = 2, 3D

.sttn_ Yes ASCII / Binary Nodal thermal stress *Key_Thermal_Stress = 1

.elss_ Yes ASCII Element 1-3 stress flag always

.sran_ / .srac_ Yes ASCII / Binary Nodal strain tensor always

.gcor_ Yes ASCII Gauss-point coordinates always

.damg_ Yes ASCII Gauss-point damage factor cohesive analyses

.elgn_ Yes ASCII Number of Gauss points per element always

.sifs_ Yes ASCII KI, KII for both tips of every crack always

.sift_ Yes ASCII SIF time history stack always

.prst_ Yes ASCII Propagation speed + SIFs at specified tip *DY_Save_Propagation_Speed_at_Specified_Tip = 1

.enee_ Yes ASCII Fracture-energy increment cohesive analyses

.crax_ / .cray_ Yes ASCII 2D/3D crack polyline X / Y always

.craz_ Yes ASCII 3D crack polyline Z 3D

.crxo_ / .cryo_ Yes ASCII Original (un-disposed) crack coords restart runs

.cnox_ / .cnoy_ / .cnoz_ Yes ASCII 3D crack-meshed-node coords 3D

.cms1_ / .cms2_ / .cms3_ Yes ASCII Crack-surface triangle connectivity 3D

.cmso_ Yes ASCII Crack-mesh outline 3D

.cmap_ Yes ASCII Crack-mesh aperture (3D) 3D

.cape_ Yes ASCII Crack calc-point aperture HF / cohesive

.capf_ Yes ASCII Aperture at fluid elements (3D HF) 3D HF

.ctap_ Yes ASCII Crack tangential opening cohesive / contact

.cvpx_ … .cvzz_ Yes ASCII Crack vertex coords + 9-axis tangents 3D

.apex_ / .apey_ Yes ASCII Calc-point coordinates 2D HF

.cori_ Yes ASCII Calc-point orientation angles 2D HF

.cpre_ / .cvel_ / .cqua_ Yes ASCII Calc-point pressure / flow velocity / quantity HF

.cohx_ / .cohy_ Yes ASCII Cohesive tractions X / Y cohesive

.crrd_ Yes ASCII Crack radius (radial cracks) *Key_Save_Crack_Radius = 1

.ennd_ / .enns_ / .ennh_ / .ennj_ Yes ASCII Enriched-node type per crack / cross / hole / inclusion always

.elty_ / .elts_ / .elth_ / .eltj_ Yes ASCII Element type per crack / cross / hole / inclusion always

.posi_ / .poss_ / .posh_ / .posj_ Yes ASCII Signed-distance sign per node per feature always

.njel_ / .nods_ Yes ASCII Crack-node / host-element associations always

.celt_ / .celv_ / .celj_ / .celc_ Yes ASCII Tip / vertex / junction / intersection coords always

.ctty_ Yes ASCII Crack-tip type always

.blab_ Yes ASCII Crack baseline vectors always

.blvx_ / .blvy_ / .blvz_ Yes ASCII Baseline direction-vector components always

.tere_ Yes ASCII Tip-enriched node element number always

.cndx_ / .cndy_ / .cndz_ Yes ASCII Crack-node S1 vector (CFCP-2) *CFCP = 2

.hlcr No ASCII Circular hole coordinates holes enabled

.ehcr No ASCII Elliptical hole parameters holes enabled

.jzcr No ASCII Circular inclusion coordinates inclusions enabled

.jzpx / .jzpy No ASCII Polygonal inclusion vertices inclusions enabled

.cscr No ASCII Cross-interface coordinates cross enabled

.nfcx / .nfcy / .nfcz No ASCII Natural-fracture vertex coordinates (3D) natural fractures

.ncrx / .ncry No ASCII Natural-crack endpoint coords (2D) natural fractures

.ener Append ASCII Energy balance per step always

.edye Append ASCII Explicit-dynamics energy history explicit dynamics

.edtm Append ASCII Explicit-dynamics time history explicit dynamics

.edap Append ASCII Explicit-dynamics aperture history (3D) explicit dynamics

.dcrl / .dprl Append ASCII Crack total / propagation length history dynamic 2D

.idtm Append ASCII Implicit-dynamics time history implicit dynamics

.iite / .ilth / .ipre Append ASCII iFrac iterations / length / pressure HF

.lpmf_ / .lpmx_ / .lpma_ Yes ASCII Lumped mass per node (FEM / enriched / both) dynamic

.hftm Append ASCII HF macro/fracture time log HF

.injp Append ASCII Injection-pressure history HF

.wbfp No ASCII Wellbore fracturing path HF

.wbpt Append ASCII Wellbore / stage / proppant pressure vs time HF

.ihft No ASCII HF time per fracture step HF

.icpt / .icpt_LS / .icpt_CT No ASCII CPU-time per step (total / linear-solver / contact) HF

.ccon_ / .pokf_ / .cond_ / .wpnp_ / .epcr_ Yes ASCII Proppant transport outputs *Key_Propp_Trans = 1

.Saved_Filename Append ASCII Flow rate at specific point HF

.elcs_ / .elco_ Yes ASCII Element contact / cohesive state contact / cohesive

.kiel_ Yes ASCII Killed (broken) element IDs element deactivation

.fxdf_ / .fydf_ / .fzdf_ Yes ASCII DOF internal force vectors always

.fxsl_<iSL>_ / .fysl_<iSL>_ / .fzsl_<iSL>_ Yes ASCII Surface-load internal force vectors 3D surface loads

.skxf No Binary XFEM element stiffness matrices always (debug)

.csrn_ / .csra_ / .csrj_ / .csri_ Yes ASCII CSR stiffness matrix always (debug)

.fenx_ … .fezz_ Yes ASCII Fluid-element normals / up-low / local axes (3D HF) 3D HF

.fnnx_ / .fnny_ / .fnnz_ Yes ASCII Fluid-node normals 3D HF

.fnux_ / .fnuy_ / .fnuz_ / .fnlx_ / .fnly_ / .fnlz_ Yes ASCII Up-face / low-face crack-node displacements 3D HF

.cpfn_ / .cpno_ Yes ASCII Fluid-node count / numbers per crack 3D HF

.ccpx_ / .ccpy_ / .ccpz_ Yes ASCII Fluid-node coordinates 3D HF

.cnlx_ / .cnly_ / .cnlz_ Yes ASCII Crack-node local coords 3D HF

.cmse_ Yes ASCII Element containing each crack node 3D HF

.fraz No ASCII Fracture-zone bounding box always

.seed No ASCII Random-number seed stochastic analyses

.post No ASCII MATLAB post-processor header always

.fdcu / .fccu No ASCII Force-displacement / Force-COD curves displacement control

.rbco_ Yes ASCII Rigid-ball (circle) coordinates rigid-ball contact

.fdvl_ Yes ASCII Per-node fluid velocity HF

.ecfv_ Yes ASCII Element-centroid field value HF

.sccx_ / .sccy_ / .scdx_ / .scdy_ Yes ASCII Stress-corrosion-cracking coords / displacements SCC analyses

PhiPsi_Console_Window.log Append text Console-window capture always

current_folder.dat No text Last-used Work_Directory always

End of manual

For keyword reference, see PhiPsi Keywords Manual. For the project homepage, see http://phipsi.top.

If you find a missing file extension or a format that disagrees with the PhiPsi data, please report it to the author (see email at top).

Feature	Files read	Columns / fields used
Displacement magnitude	`*.disn_<i>`	`node_id, Ux, Uy` (2D comma) or `Ux, Uy, Uz` (3D space). Magnitude = `sqrt(Ux² + Uy² + …)`.
Displacement X / Y / Z	`*.disn_<i>`	single component.
Stress σxx / σyy / σxy / σvm	`*.strn_<i>`	2D = 4 stress columns; 3D = 6 stress columns.
Stress σzz / σyz / σxz	`*.strn_<i>`	3D-only columns.
Cylindrical stress σrr / σθθ / σrθ	`*.stnc_<i>`	3D-only columns.
Strain	`*.sran_<i>`	2D = 4 strain columns; 3D = 7.
Stress / strain at Gauss points	`.strg_<i>`, `.disg_<i>`	one row per Gauss point.
Enriched-node indicator	`.ennd_<i>`, `.elty_<i>`	integer per node / element.
Enriched-DOF displacement	`*.dien_<i>`	zero for non-enriched.
Full cloud (any field)	`*.vtk`	`SCALARS` fields written by `Save_vtk_file.f90` (stress, displacement, material ID, etc.).
Crack displacement (3D)	`.fnux_<i>`, `.fnlx_<i>`	up- and low-face displacement at crack nodes.

Feature	Files read	X-axis options	Y-axis options
Energy vs step / growth length	`*.ener`	`iter` (step #), or `Crack_Propagation_Length` (col 7)	`Elastic_Strain_Energy`, `Fracture_Energy`, `External_Work`, `Residual_Energy`, `Normalized_Residual_Energy`
Explicit-dynamics energy	`*.edye`	`time`, `iter`	`T`, `U`, `T+U`, `W`
SIF history	`*.sifs_<i>` (NEWFTU-2026041702 stack)	step #	`KI_tip1`, `KII_tip1`, `KI_tip2`, `KII_tip2`
Crack length / growth	`.dcrl`, `.dprl`	`iter`, `time`	`Crack_1_Length`
Displacement at a node	`*.disn_<i>`	node index	`Ux`, `Uy`
Velocity / acceleration at a node	`.veln_<i>`, `.acln_<i>` (NEWFTU-2026041702)	node index	single component
Lumped-mass	`.lpmf_<i>`, `.lpma_<i>`	node index	`mass`

Feature	Files read	Columns / fields used
Displacement arrows	`*.disn_<i>`	`(Ux, Uy)` (2D) or `(Ux, Uy, Uz)` (3D).
Velocity arrows	`*.veln_<i>`	as above.
Block / baseline vectors	`.blvx_<i>`, `.blvy_<i>`, `*.blvz_<i>`	one axis per file.
Fluid-element local axes	`.fexx_<i>` … `.fezz_<i>`	nine-component basis.
Original boundary forces	`.focx`, `.focy`, `*.focz` (input)	`node_id, force_value`.

Feature	Files read	Notes
2D crack polyline	`.crax_<i>`, `.cray_<i>`	per-crack rows of X, Y coordinates.
2D crack aperture	`*.cape_<i>`	aperture colour map.
2D crack orientation	`*.cori_<i>`	used for tip-extension direction.
2D enriched element types	`.elty_<i>`, `.ennd_<i>`	colour-code tip / Heaviside / junction elements.
2D calc-point overlay	`.apex_<i>`, `.apey_<i>`	HF analysis pressure / aperture.
3D crack surface mesh	`.cnox_<i>`, `.cnoy_<i>`, `.cnoz_<i>` + `.cms1_<i>`, `.cms2_<i>`, `.cms3_<i>`	triangle vertex coords + triangle connectivity.
3D crack aperture	`.cmap_<i>`, `.cape_<i>`	colour map on the crack surface.
3D crack outline	`*.cmso_<i>`	boundary polygon.
3D natural fractures	`.nfcx`, `.nfcy`, `*.nfcz`	read once.
Clipped crack variants	`.cnxc_<i>`, `.cnyc_<i>`, `.cnzc_<i>`, `.cmc1_<i>` …	when the model is sliced by a plane.
Crack-aperture history	`*.cape_<i>` for `i = 1, 2, …, n`	frame-by-frame aperture animation.

Source	Behavior
`<name>_NNNNN.vtk` sequence	Loaded into PyVista; each frame is a `vtkUnstructuredGrid` rendered in turn.
`<name>_<i>.disn_<i>` / `.strn_<i>` / `.crax_<i>` etc. sequence	Each frame's results are mapped onto the same `.node` / `.elem` mesh, then exported as PNG and stitched into a GIF (`WorkerThread_Generate_Animation` in `pp_utilities.py`).
3D crack frame	`.crax_<i>` / `.cray_<i>` / `.craz_<i>` for 2D; `.cms1/2/3_<i>` for 3D.

Extension	2D	3D	Columns	Required	Reader	Purpose
`.kpp`	Y	Y	text	Yes	`PhiPsi_Read_Input.F90`	Keyword / control input
`.node`	Y	Y	2 / 3	Yes	`Read_Geo*.F90`	Node coordinates
`.elem`	Y	Y	5 / 9	Yes	`Read_Geo*.F90`	Element connectivity + material
`.boux`	Y	Y	1	No	`Read_Geo*.F90`	X-DOF zero constraint
`.bouy`	Y	Y	1	No	`Read_Geo*.F90`	Y-DOF zero constraint
`.bouz`	–	Y	1	No	`Read_Geo_3D.F90`	Z-DOF zero constraint
`.buxn`	Y	Y	2	No	`Read_Geo*.F90`	Non-zero prescribed X disp.
`.buyn`	Y	Y	2	No	`Read_Geo*.F90`	Non-zero prescribed Y disp.
`.buzn`	–	Y	2	No	`Read_Geo_3D.F90`	Non-zero prescribed Z disp.
`.focx`	Y	Y	2	No	`Read_Geo*.F90`	X-direction point load
`.focy`	Y	Y	2	No	`Read_Geo*.F90`	Y-direction point load
`.focz`	–	Y	2	No	`Read_Geo_3D.F90`	Z-direction point load
`.ivex` / `.ivey`	Y	Y	2	No	`Read_Geo*.F90`	Initial velocity X / Y
`.ivez`	–	Y	2	No	`Read_Geo_3D.F90`	Initial velocity Z
`.iacx` / `.iacy`	Y	Y	2	No	`Read_Geo*.F90`	Initial acceleration X / Y
`.iacz`	–	Y	2	No	`Read_Geo_3D.F90`	Initial acceleration Z
`.idpx` / `.idpy`	–	Y	2	No	`Read_Geo_3D.F90`	Initial displacement X / Y (3D only)
`.idpz`	–	Y	2	No	`Read_Geo_3D.F90`	Initial displacement Z
`.dofx` / `.dofy`	Y	Y	2	No	`Read_Geo*.F90`	Multi-point-constraint coupling sets
`.fbvl` / `.fbqn` / `.fbiv`	Y	–	2	No	`Src_Field_Prob/`	Field-problem boundary value / flux / initial
`.bhpc`	Y	–	2	Conditional	`Read_Geo*.F90`	Wellbore pressure curve (Key_Analysis_Type 16 / 17)
`.eqnl`	–	Y	1	Conditional	`Read_Geo_3D.F90`	Earthquake acceleration nodes (EQ_Ac_nodes_list_method = 2)
`.boud` / `.focd`	Y	Y	text	No (PPView metadata)	`PPView/Open_Read_Update_kppFile.py`	PPView geometry metadata

Extension	Step suffix	Format	Purpose	Enabling keyword
`_<isub5>.vtk`	Yes (zero-padded 5)	ASCII	Main solution snapshot (ParaView)	`*Key_Save_vtk = 1`
`_CRACK_<isub5>.vtk`	Yes	ASCII	Crack geometry snapshot	`*Key_Save_vtk = 1`
`.disp_<i>`	Yes	ASCII / Binary	Global DOF displacement vector	always (unless `*Key_Save_Nothing = 1`)
`.disn_<i>`	Yes	ASCII / Binary	Nodal displacement (`Ux, Uy[, Uz]`)	always
`.dien_<i>`	Yes	ASCII / Binary	Enriched-DOF displacement	always
`.edei_<i>`	Yes	ASCII	Enriched-DOF index map	always
`.disg_<i>`	Yes	ASCII	Gauss-point displacement	always
`.dipc_<i>` / `.dinc_<i>`	Yes	ASCII / Binary	Cylindrical-coord displacement	`*Key_CoorSys = 2`
`.veln_<i>` / `.acln_<i>`	Yes	ASCII	Per-node velocity / acceleration	dynamic analyses only
`.strn_<i>`	Yes	ASCII / Binary	Nodal stress tensor	always
`.strg_<i>`	Yes	ASCII / Binary	Gauss-point stress tensor	always
`.stnc_<i>`	Yes	ASCII	Nodal stress in cylindrical	`*Key_CoorSys = 2`, 3D
`.sttn_<i>`	Yes	ASCII / Binary	Nodal thermal stress	`*Key_Thermal_Stress = 1`
`.elss_<i>`	Yes	ASCII	Element 1-3 stress flag	always
`.sran_<i>` / `.srac_<i>`	Yes	ASCII / Binary	Nodal strain tensor	always
`.gcor_<i>`	Yes	ASCII	Gauss-point coordinates	always
`.damg_<i>`	Yes	ASCII	Gauss-point damage factor	cohesive analyses
`.elgn_<i>`	Yes	ASCII	Number of Gauss points per element	always
`.sifs_<i>`	Yes	ASCII	KI, KII for both tips of every crack	always
`.sift_<i>`	Yes	ASCII	SIF time history stack	always
`.prst_<i>`	Yes	ASCII	Propagation speed + SIFs at specified tip	`*DY_Save_Propagation_Speed_at_Specified_Tip = 1`
`.enee_<i>`	Yes	ASCII	Fracture-energy increment	cohesive analyses
`.crax_<i>` / `.cray_<i>`	Yes	ASCII	2D/3D crack polyline X / Y	always
`.craz_<i>`	Yes	ASCII	3D crack polyline Z	3D
`.crxo_<i>` / `.cryo_<i>`	Yes	ASCII	Original (un-disposed) crack coords	restart runs
`.cnox_<i>` / `.cnoy_<i>` / `.cnoz_<i>`	Yes	ASCII	3D crack-meshed-node coords	3D
`.cms1_<i>` / `.cms2_<i>` / `.cms3_<i>`	Yes	ASCII	Crack-surface triangle connectivity	3D
`.cmso_<i>`	Yes	ASCII	Crack-mesh outline	3D
`.cmap_<i>`	Yes	ASCII	Crack-mesh aperture (3D)	3D
`.cape_<i>`	Yes	ASCII	Crack calc-point aperture	HF / cohesive
`.capf_<i>`	Yes	ASCII	Aperture at fluid elements (3D HF)	3D HF
`.ctap_<i>`	Yes	ASCII	Crack tangential opening	cohesive / contact
`.cvpx_<i>` … `.cvzz_<i>`	Yes	ASCII	Crack vertex coords + 9-axis tangents	3D
`.apex_<i>` / `.apey_<i>`	Yes	ASCII	Calc-point coordinates	2D HF
`.cori_<i>`	Yes	ASCII	Calc-point orientation angles	2D HF
`.cpre_<i>` / `.cvel_<i>` / `.cqua_<i>`	Yes	ASCII	Calc-point pressure / flow velocity / quantity	HF
`.cohx_<i>` / `.cohy_<i>`	Yes	ASCII	Cohesive tractions X / Y	cohesive
`.crrd_<i>`	Yes	ASCII	Crack radius (radial cracks)	`*Key_Save_Crack_Radius = 1`
`.ennd_<i>` / `.enns_<i>` / `.ennh_<i>` / `.ennj_<i>`	Yes	ASCII	Enriched-node type per crack / cross / hole / inclusion	always
`.elty_<i>` / `.elts_<i>` / `.elth_<i>` / `.eltj_<i>`	Yes	ASCII	Element type per crack / cross / hole / inclusion	always
`.posi_<i>` / `.poss_<i>` / `.posh_<i>` / `.posj_<i>`	Yes	ASCII	Signed-distance sign per node per feature	always
`.njel_<i>` / `.nods_<i>`	Yes	ASCII	Crack-node / host-element associations	always
`.celt_<i>` / `.celv_<i>` / `.celj_<i>` / `.celc_<i>`	Yes	ASCII	Tip / vertex / junction / intersection coords	always
`.ctty_<i>`	Yes	ASCII	Crack-tip type	always
`.blab_<i>`	Yes	ASCII	Crack baseline vectors	always
`.blvx_<i>` / `.blvy_<i>` / `.blvz_<i>`	Yes	ASCII	Baseline direction-vector components	always
`.tere_<i>`	Yes	ASCII	Tip-enriched node element number	always
`.cndx_<i>` / `.cndy_<i>` / `.cndz_<i>`	Yes	ASCII	Crack-node S1 vector (CFCP-2)	`*CFCP = 2`
`.hlcr`	No	ASCII	Circular hole coordinates	holes enabled
`.ehcr`	No	ASCII	Elliptical hole parameters	holes enabled
`.jzcr`	No	ASCII	Circular inclusion coordinates	inclusions enabled
`.jzpx` / `.jzpy`	No	ASCII	Polygonal inclusion vertices	inclusions enabled
`.cscr`	No	ASCII	Cross-interface coordinates	cross enabled
`.nfcx` / `.nfcy` / `.nfcz`	No	ASCII	Natural-fracture vertex coordinates (3D)	natural fractures
`.ncrx` / `.ncry`	No	ASCII	Natural-crack endpoint coords (2D)	natural fractures
`.ener`	Append	ASCII	Energy balance per step	always
`.edye`	Append	ASCII	Explicit-dynamics energy history	explicit dynamics
`.edtm`	Append	ASCII	Explicit-dynamics time history	explicit dynamics
`.edap`	Append	ASCII	Explicit-dynamics aperture history (3D)	explicit dynamics
`.dcrl` / `.dprl`	Append	ASCII	Crack total / propagation length history	dynamic 2D
`.idtm`	Append	ASCII	Implicit-dynamics time history	implicit dynamics
`.iite` / `.ilth` / `.ipre`	Append	ASCII	iFrac iterations / length / pressure	HF
`.lpmf_<i>` / `.lpmx_<i>` / `.lpma_<i>`	Yes	ASCII	Lumped mass per node (FEM / enriched / both)	dynamic
`.hftm`	Append	ASCII	HF macro/fracture time log	HF
`.injp`	Append	ASCII	Injection-pressure history	HF
`.wbfp`	No	ASCII	Wellbore fracturing path	HF
`.wbpt`	Append	ASCII	Wellbore / stage / proppant pressure vs time	HF
`.ihft`	No	ASCII	HF time per fracture step	HF
`.icpt` / `.icpt_LS` / `.icpt_CT`	No	ASCII	CPU-time per step (total / linear-solver / contact)	HF
`.ccon_<i>` / `.pokf_<i>` / `.cond_<i>` / `.wpnp_<i>` / `.epcr_<i>`	Yes	ASCII	Proppant transport outputs	`*Key_Propp_Trans = 1`
`.Saved_Filename`	Append	ASCII	Flow rate at specific point	HF
`.elcs_<i>` / `.elco_<i>`	Yes	ASCII	Element contact / cohesive state	contact / cohesive
`.kiel_<i>`	Yes	ASCII	Killed (broken) element IDs	element deactivation
`.fxdf_<i>` / `.fydf_<i>` / `.fzdf_<i>`	Yes	ASCII	DOF internal force vectors	always
`.fxsl_<iSL>_<i>` / `.fysl_<iSL>_<i>` / `.fzsl_<iSL>_<i>`	Yes	ASCII	Surface-load internal force vectors	3D surface loads
`.skxf`	No	Binary	XFEM element stiffness matrices	always (debug)
`.csrn_<i>` / `.csra_<i>` / `.csrj_<i>` / `.csri_<i>`	Yes	ASCII	CSR stiffness matrix	always (debug)
`.fenx_<i>` … `.fezz_<i>`	Yes	ASCII	Fluid-element normals / up-low / local axes (3D HF)	3D HF
`.fnnx_<i>` / `.fnny_<i>` / `.fnnz_<i>`	Yes	ASCII	Fluid-node normals	3D HF
`.fnux_<i>` / `.fnuy_<i>` / `.fnuz_<i>` / `.fnlx_<i>` / `.fnly_<i>` / `.fnlz_<i>`	Yes	ASCII	Up-face / low-face crack-node displacements	3D HF
`.cpfn_<i>` / `.cpno_<i>`	Yes	ASCII	Fluid-node count / numbers per crack	3D HF
`.ccpx_<i>` / `.ccpy_<i>` / `.ccpz_<i>`	Yes	ASCII	Fluid-node coordinates	3D HF
`.cnlx_<i>` / `.cnly_<i>` / `.cnlz_<i>`	Yes	ASCII	Crack-node local coords	3D HF
`.cmse_<i>`	Yes	ASCII	Element containing each crack node	3D HF
`.fraz`	No	ASCII	Fracture-zone bounding box	always
`.seed`	No	ASCII	Random-number seed	stochastic analyses
`.post`	No	ASCII	MATLAB post-processor header	always
`.fdcu` / `.fccu`	No	ASCII	Force-displacement / Force-COD curves	displacement control
`.rbco_<i>`	Yes	ASCII	Rigid-ball (circle) coordinates	rigid-ball contact
`.fdvl_<i>`	Yes	ASCII	Per-node fluid velocity	HF
`.ecfv_<i>`	Yes	ASCII	Element-centroid field value	HF
`.sccx_<i>` / `.sccy_<i>` / `.scdx_<i>` / `.scdy_<i>`	Yes	ASCII	Stress-corrosion-cracking coords / displacements	SCC analyses
`PhiPsi_Console_Window.log`	Append	text	Console-window capture	always
`current_folder.dat`	No	text	Last-used `Work_Directory`	always