OpenRadioss time-history files (<run>T01, T02, …)

The time-history file an OpenRadioss (or Radioss) run writes (/TFILE in the engine deck): at each output time, the global energies and momenta, the variables of every part and subset, and the variables each /TH/<kind> group of the starter deck asks for (nodes, bricks, shells, springs, rigid bodies, interfaces, sections…). It holds numbers per entity, not a mesh; the model is read from the starter deck by radioss, and its animation files by radioss_anim. New in v16.12.0.

Format name	radioss_th
File names	a stem, then T and two digits, no extension (crashT01; a restart run writes crashT02…); also recognised by content, its title record
Read / Write	✓ / — (read-only)
Extra dependencies	—

Reading

import meshioplusplus

first = meshioplusplus.read("crashT01")                  # the first output
last = meshioplusplus.read("crashT01", time_step=-1)     # the last one

last.field_data["meshio:time"]
last.field_data["radioss_th:global:kinetic_energy"]      # one value
last.field_data["radioss_th:part:1:IE"]                  # part 1's internal energy
last.field_data["radioss_th:node:1"]                     # TH group 1 (nodes): (nodes, variables)
last.field_data["radioss_th:node:1:ids"]                 # its node ids
last.field_data["radioss_th:node:1:variables"]           # its variable codes

meshioplusplus.radioss_th.time_values("crashT01")
for time, mesh in meshioplusplus.read_sequence("crashT01"):
    ...

meshioplusplus info crashT01

Both engines read the whole format: the C++ core, and a Python reference reader the core falls back to.

The file

A big-endian Fortran unformatted file (each record framed by its length). First the descriptions:

• a title record (the file version, then 80 characters) and the run's date;
• from version 3051 on, three more records, the last the mass, length and time unit factors;
• the counts of parts, materials, properties, subsets, TH groups and global variables, and the global variables' codes;
• each part (id, title, its variable codes), material and property (id, title), subset (id, child subsets, parts, variable codes, title), and TH group (id, type, entity count, variable count, title; each entity's id and title; the variable codes).

Titles are 40 characters before version 3041, 80 up to 4020 and 100 from 4021. Then one output per time: the time, the global variables, the part variables, the subset variables and one record per TH group (entities × variables).

Steps and data

The steps are the outputs, in file order. A run stopped while writing leaves an incomplete last output, which is not read. Each step has no points (an empty vertex block) and holds field data only:

• meshio:time: the output's time.
• Global variables, one value each, named by their code: radioss_th:global:internal_energy, kinetic_energy, x_momentum, y_momentum, z_momentum, mass, time_step, rotation_energy, external_work, spring_energy, contact_energy, hourglass_energy, elastic_contact_energy, frictional_contact_energy, damping_contact_energy, plastic_work, added_mass, percentage_added_mass, inlet_mass, outlet_mass, inlet_energy, outlet_energy (codes 1 to 22; others var<code>).
• Part and subset variables, one value each: radioss_th:part:<id>:<name> and radioss_th:subset:<id>:<name>, the name Radioss's keyword for the code (IE, KE, XMOM, YMOM, ZMOM, MASS, HE, TURBKE, XCG…ZCG, XXMOM…ZZMOM, IXX…IZX, RIE, KERB, RKERB, RKE, ERODED, HEAT, VX, VY, VZ, PW; others var<code>).
• TH groups: radioss_th:<kind>:<id>, an (entities × variables) array, with :ids (the entity ids) and :variables (the variable codes, in column order). The kind comes from the group's type: node (0), brick (1), quad (2), shell (3), truss (4), beam (5), spring (6), sh3n (7), sphcel (51), inter (101), rwall (102), rbody (103), sectio (104), monvol (107), accel (108); others type<n>.
• radioss_th:unit_factors: the mass, length and time factors, in files that have them.

arrays keeps only the named field data; points_only keeps only the time.

Not read

• The titles (the run's, the parts', the groups' and their entities') and the date.
• The names of the TH group variables. The file stores their codes; the names (DX, SX, FNX…) are in Radioss's own tables, per group kind, and th_to_csv reads them from a <run>T01_TITLES file the engine does not write by default.

Verification

The layout follows OpenRadioss's th_to_csv converter (MIT). The test suite reads a T01 that OpenRadioss wrote for a meshio++ deck (two bricks, one end held, the other pushed; see tests/python/meshes/radioss_th/column/README.md), and every value of its 8 outputs equals th_to_csv's reading to the 7 digits it prints; the two engines agree exactly. Outside the suite, the 81 T01 files of OpenRadioss's QA tests read the same in both engines and match th_to_csv on every file it reads correctly (it miscounts files with a single output). Newer layouts (version 3051 and later, with unit factors and longer titles) are tested on synthetic files only: every OpenRadioss file seen is version 3040.