Octo for aerospace simulation
Nastran, Abaqus, OptiStruct, Fluent and STAR-CCM+ run headless on Linux, with syntax documented by the vendors. Octo can prepare and check the decks (solver input files), set up the batches, read the results in Python and flag negative margins for human review. Assumptions, approval and sign-off belong to your engineering team.
Six possible deliverables, all in repetitive, verifiable work and all prepared for human review. None replaces the stress engineer or certification approval.
From a base model, it can generate Nastran or OptiStruct deck variations (load cases, thicknesses, materials) and check them with pyNastran, an open library: cards, duplicate IDs, properties without material. In OptiStruct, it proposes running -check, which only verifies the deck, before the solution.
It can set up the scripts that submit dozens of Nastran, Abaqus, Fluent or STAR-CCM+ cases to the cluster scheduler, each with the solver's documented syntax, and then look for FATAL, ERROR and lack of convergence in the .f06, .msg, .log and .trn files.
It can read the OP2 (Nastran binary result) with pyNastran and the ODB (Abaqus result) with Abaqus's own Python (odbAccess, no screen) and pull what the team asks for: maximum displacement, stresses per element, fastener forces, frequencies, flutter speed per mode.
It can recalculate simple margins of safety, MS = allowable/(FS·stress) − 1 (FS: factor of safety), with the allowables and factors your team provides, and flag the negative ones and those that changed between model revisions. The assumption belongs to engineering.
It can put two versions of the global finite element model (GFEM) or two result sets side by side and list what changed, where and by how much, for engineering to assess.
Deliverable: difference report between revisionsIt can write the draft of the stress report, the load case table and the record of assumptions and software versions used, for the engineer to review and sign.
Deliverable: draft for the engineer's review and signatureThe same Octo cycle, applied to structural simulation and computational fluid dynamics (CFD). Each arm has a narrow role; the decisions are made by a person on your engineering team.
Which solvers, versions and licenses exist, what the executable is called on your installation (it varies: nastran, nast20241), and which files there are: .bdf, .inp, .fem, .cas.h5, .sim.
Cards in 8- or 16-character fields or free-field with commas; output in F06, OP2 or HDF5; ODB read through odbAccess. Allowables and the factor of safety come from your team, not from the script.
Doesn't change the base model: it generates variations alongside it. Opens the ODB read-only. Nothing runs without a license and installation, and certification analysis is decided and signed by qualified people and authorities.
Nastran for the global model and aeroelasticity (SOL 144, 145, 146); Abaqus for contact and damage; OptiStruct for optimization; Fluent or STAR-CCM+ for CFD. Sizes with smp=/dmp=, cpus=, -nt or -np.
Deck with PARAM,POST,-1 to output OP2; Fluent journal (command script) with rc, it and wd; Java macro in STAR-CCM+; Python 3.10 in Abaqus, converting old scripts with abqPy2to3.
Before the batch, a small case with a known result. Checks by content: FATAL in the .f06, errors in the .msg and the .trn, convergence. In Fluent with “Exit on Error”, the exit code also counts.
With your OK, it sends the cases to the cluster scheduler and checks case by case what converged and what failed, without taking the end of the process as proof of a result.
Each solver's version, syntax confirmed on your installation, load cases and assumptions used. The next model revision starts with the history ready.
Nothing runs in batch without your OK. No margin goes out signed by Octo.
The criteria Octo proposes for choosing. The benefit lies in what has a command line and a text file; the graphical interface stays with engineering.
| Task | Software | Headless path |
|---|---|---|
| Global model statics, internal loads | MSC or Simcenter Nastran (SOL 101) | nastran gfem.bdf ... → OP2 → pyNastran |
| Modes and frequencies | Nastran (SOL 103), Abaqus, MAPDL | nastran; abaqus job=; ansys261 -b |
| Flutter and divergence | Nastran SOL 145; ZAERO | Deck with aero cards (CAERO, FLUTTER); ZAERO through a text file |
| Gust loads, dynamic aeroelasticity | Nastran SOL 146; ZAERO; Patran Flightloads | Nastran deck; Flightloads is an interface |
| Nonlinear, contact, impact, composite damage | Abaqus Standard/Explicit; OptiStruct 2026.1 | abaqus job= interactive; optistruct -nt |
| Topology or sizing optimization | OptiStruct; Nastran SOL 200 | optistruct file.fem -lic OPT |
| External CFD (lift, drag) | Fluent, STAR-CCM+ | fluent 3ddp -g -i x.jou; starccm+ -batch |
| Turbomachinery | CFX, Fluent | PyCFX (2026 R1); journal |
| Aerodynamic noise | STAR-CCM+ (Ffowcs Williams-Hawkings acoustic model), PowerFLOW | starccm+ -batch (PowerFLOW not detailed) |
| Batch post-processing | pyNastran, abaqus python, Fluent journal | Python reading of the results file, read-only |
Three steps. Each one only makes sense after the previous one has shown results in your engineering team.
A proposal, not a promise
With the result files in hand, even without the solver on the machine, you ask in engineering terms and get the table to review.
Cases are generated, submitted and checked by the same script, in the scheduler you already use.
With each new GFEM version, the comparison and the draft report come out together with the results.
Every point below has a source published by the vendor, the project or the responsible agency. The sources are in the next section.
5
points with a published source, each with its reference alongside.
-g runs with no interface or graphics, and -i reads the journal. With “Exit on Error”, it returns 0 on a normal finish and 1 or 2 on errors and license failures.Source: Fluent User's Guide 2026 R1, “Running Ansys Fluent in Batch Mode”abaqus python -m abqPy2to3 utility does the conversion.Source: Abaqus 2024 What's New; SIMULIA CommunityOcto prepares everything, but does not sign. The document of record stays with whoever is accountable for it.
Surveys, calculates, organizes and generates the documents: spreadsheets, reports, drawings and drafts.
Deliverable: material ready to checkThe licensed professional checks what Octo delivered before signing. If something doesn't add up, it goes back to Octo with the correction.
Step: review by the signerOcto does not sign. Designs, technical reports, ART/RRT (Brazil's professional responsibility records), accountability reports and any official document are still signed by the company's or agency's licensed professional: here, the responsible engineer and the certification authority.
Sign-off: responsible engineer and certification authorityVendor documentation and announcements used in the research.
The assessment starts by reading your decks, results and installations, without changing anything. You get a map of what can be automated and decide with it in hand.