OS-E: 0125 Diagnose Non-converged Solution using NLMON
Modeled using solid and shell elements and when the solution is not converged, run diagnostics modeling errors using NLMON.
Figure 1. FE-Model
Model Description
The cantilever beam model is shown in Figure 1, and both the elements joined by merging the common nodes. This
example simulation is with nonlinear static solution with large displacement.
- FE Model
- Element Types
- CHEXA
- MAT1
- Young’s Modulus
- 2.1E5 MPA
- Poisson Ratio
- 0.3
- Density
- 7.8E
Results
Note: NLMON toolkit is for nonlinear convergence monitoring and debugging (load
NLMON_NL.h3d file). Import the TCL script from HyperView to launch NLMON utility tool from this location in the
HyperWorks installation:
<Altair_Home>\hwsolvers\scripts\ os_out_file_parser.tcl and load
the .out file in this utility to sync it with HyperView. NLMON works with large and small displacement
problems.
In the .out file, notice the max displacement
increment and correction is at node 13 (Figure 2). Load the NLMON_nl.h3d file and the
.out file using NLMON utility tool to sync. Click on the maximum
displacement increment or maximum displacement correction on the NLMON utility (Figure 4) and notice that elements (shell elements rotations) are
not clamped correctly (animate for better visualization) in HyperView page, as shown in Figure 3
.
Tip: To improve convergence, use TIE or
FREEZE contact to connect shell and solid elements.
Figure 2. OptiStruct OUT File
Figure 3. Non-Converge Results of Maximum Displacement Increment . and Correction Results in HyperView
Figure 4. Non-Converge Results of Maximum Displacement Increment . and Correction Results in NLMON Utility Page
Model Files
The model files used in this example include:
<install_directory>/demos/hwsolvers/optistruct/examples/NLMON.fem