Why does abaqus not start analysis after submitting the job?

Abaqus failing to initiate an analysis after job submission is almost invariably a pre-processing or environmental configuration issue, not a problem with the solver itself. The software performs a series of checks and file operations before the analysis core begins, and a failure at this stage halts the process silently or with an ambiguous error. The root cause typically resides in one of three areas: an error in the model definition that prevents the creation of the input file, an issue with the licensing or environment that blocks the solver's launch, or insufficient system resources to begin the initial processing phase. Unlike errors that occur during the analysis, which often produce explicit error messages in the .msg or .dat files, a failure to start often results in a job that appears to hang in "Submitted" status or terminates quickly with minimal output, making diagnosis more challenging.

The most common technical culprit is a problem with the model's input file generation. This can occur if there is a severe error in the CAE model, such as an invalid material definition, an incorrectly defined step or interaction, or a corrupted part instance. When you submit the job, Abaqus/CAE first writes the `inp` file; if this process fails due to an unresolvable inconsistency, the job submission effectively ends there. Checking the `dat` file immediately after submission is critical, as it may contain the first fatal error. Another frequent cause is an incorrect or inaccessible file path for the job directory, especially if it contains spaces or special characters, or if the user lacks write permissions. The solver, `standard.exe` or `explicit.exe`, cannot launch if it cannot read the `inp` file or write the initial log files to the specified location.

From an environmental perspective, licensing failures are a primary suspect. If the Abaqus license manager cannot check out a token for the required feature (like "Abaqus/Standard" or "Abaqus/Explicit"), the solver process will not start. This can be due to an expired license, a full license pool, incorrect environment variables like `LM_LICENSE_FILE`, or firewall settings blocking communication with the license server. Concurrently, system resource bottlenecks—particularly a lack of available RAM or disk space on the scratch drive—can prevent the analysis from initializing. The solver requires significant memory just to read the input file and assemble the initial matrices; if the system cannot allocate this, the process will abort. On high-performance computing clusters, issues with the submission script, queueing system directives, or MPI configuration can similarly prevent the solver executable from ever launching.

Effective troubleshooting requires a methodical examination of the output sequence. First, verify the job's `.log` file for any immediate errors. Second, inspect the `.dat` file, which may contain preprocessing errors. Third, confirm the license status via the `lmstat` command and validate that the `.odb` and other lock files are being created in the working directory. If the job is submitted via a script, ensure all environment variables and paths are correctly sourced. Often, the solution involves simplifying the model to a minimal working example to isolate the defective component, checking the system's free memory and disk space, and confirming the licensing setup. The key is to recognize that a failure to start is a failure in the setup phase, and diagnostics must therefore focus on the prerequisites for the solver's execution rather than the numerical analysis itself.