[elephant]

Abaqus msg file buddy

Abaqus Standard efficiently solves nonlinear finite element analysis using automatically-scaled load increments and Newton’s method iterations. A summary of the progress toward solution is presented in the “.sta” file. Significantly more detail is recorded in the “.msg” file but it’s harder to interpret.

This free online utility highlights useful information from the .msg file and presents it in a more user-friendly format. The goal is to make it easier to understand what’s happening in the solver and to help diagnose convergence problems. This project is a work-in-progress. Comments and suggestions are welcome.

No .msg file data is transferred to the internet; the utility runs locally within your browser.

A common problem that can lead to poor convergence is the inconsistent use of units in the model. Use the free engineering unit converter web app to help eliminate that problem.

Unfortunately, your browser does not support modern JavaScript features this program requires for advanced diagnotics and plotting of data from your .msg file. Please consider upgrading to a current version of Chrome, Firefox, Safari, or Edge.

Instead, here are general links to Knowledge Base articles which may be helpful for common convergence problems in severe discontinuity and equilibrium iterations:

Description Additional Information
Debugging Abaqus/Standard divergence with too many cutbacks in the last attempted increment QA00000008780
Hints for obtaining a converged contact solution in Abaqus/Standard QA00000008797
Understanding Abaqus/Standard negative eigenvalue messages QA00000009389
What do zero pivot warnings in the message file of my Abaqus/Standard analysis mean? QA00000008866
What might cause Abaqus/Standard to diverge with numerical singularity warnings? QA00000008894
What do warnings that the current strain increment exceeds the strain to first yield mean? QA00000008867

Numerical Singularities

These warnings indicate poor conditions for the equation solver and are often produced in static steps with unconstrained rigid body motion in the indicated degree of freedom. Additional information is available in QA00000008894.

Table of Iterations

This table is a chronological summary of all the solver iterations reported in the .msg file. The Result column describes the first failed check, if any, followed by corresponding nodal data. The Value should generally decrease for each iteration within an Attempt if the nonlinear solution is converging. Here you can review the rate of convergence and any causes of difficulties. Unsuccessful Attempts are colored red.

Step Increment Attempt Step Time ΔTime Iteration Result Node DOF Value

Convergence Plots

This section summarizes the convergence measures of Iterations within the last Attempt. Choose another Attempt by clicking its Plot button in the Table of Iterations above. Curves may be suppressed by clicking their name in the legend.

Contact

This plot shows how the contact is changing within the Attempt. Contact changes are classified as "severe discontinuities" because they significantly alter the load path through the mesh. The number of contact changes should reduce as the solver iterates to resolve the contact state.

Equilibrium

The following plots summarize the evolution of equilibrium within the Attempt. Convergence is accepted when all of the checks of these parameters satisfy criteria as described in the manual. Generally, the residuals and corrections should be approaching zero as the solver iterates. The default convergence criteria work well for most problems and should not normally need adjustment.

Recurring Contact Pairs

Contact pairs in this section are sorted according to the number of times they failed convergence checks in all Iterations of all Attempts. This doesn't necessarily indicate any problem with the model but can be helpful to identify interfaces that are the most challenging for the solver. If a contact pair is failing significantly more often then you may want to review its contact definitions and behaviors. Common reasons include indeterminate friction, reversed slave/master, overly stiff penalty or direct enforcement.

Recurring Nodes

Nodes in this section are sorted according to the number of times they failed convergence checks in all Iterations of all Attempts. If a few nodes occur significantly more often than others you should review the model or results to see what might be the cause. Common reasons include hourglassing, overly coarse mesh, distortion or underconstraint. The most repeated nodes are assigned a symbol to help with identification throughout this report.

The following table shows each failed convergence check grouped by node. The Failed Check column will help differentiate contact or equilibrium issues. Review of the Step, Increment, and Attempt will help identify whether the node is a continuous problem.

Node Step Increment Attempt Iteration Failed Check DOF Value Contact Pair