In LS-OPT, one can run a multi-disciplinary optimiztion or a multi-solver type optimization problem, where the variables can be shared among the different solvers. In performing DOE or any optimization using LS-OPT, it is important that consistent experimental points are used in the evaluations. To ensure this, one can use solver experiment duplicate solver_1 [...]
Author Archive for Suri Bala
Tolerance used for Tying Slave Nodes in TIED contacts
Published by October 15th, 2008 in LS-DYNA Contact. 0 CommentsTIED contacts help “bond” two surfaces of different mesh densities. When using the default constraint method, the projection distance of the slave node onto to the closest master segment must be zero and this is achieved by LS-DYNA by updating the slave node coordinates such that it lies on the master surface. This coordinate [...]
Packing LS-DYNA Input Files for Easy Distribution (v1.1a)
Published by October 15th, 2008 in LS-DYNA Bytes. 3 CommentsIn a previous post about a simple Python script that scans a LS-DYNA input file to package all INCLUDED files recursively so the entire model can be compressed and sent to the recipient.
Based on some new suggestions, largely by Brian Wainscott, I have attached a revised script that handles the included files [...]
Material parameter identification of GURSON material requires a process of fitting using an optimization package such as LS-OPT to match against a measured response such as a test. Following is a stress-strain curve that is achieved as a process of parameter identification using LS-OPT and LS-DYNA.
Characterizing plasticity material models using data from test
Published by October 9th, 2008 in LS-DYNA Bytes. 0 CommentsIt is common to perform a uni-axial tensile test on a material sample to generate stress-strain curve for use in numerical models in LS-DYNA. The problem frequently encountered by analysts is the cleaning of the test data that is usually noisy. I recently wrote a small Python utility that takes any test generated force-deflection curve [...]
Optimizing monotonically increasing load curves
Published by October 9th, 2008 in LS-DYNA Bytes. 0 CommentsIn cases where a monotonically increasing curve such as pressure_vs_leakage in *AIRBAG or effective_stress_vs_effective_strain in plasticity models in *MAT are to be parametrically identified by an optimization software such as LS-OPT to match against a physical test, it is important to ensure that the points identified by LS-OPT satisfy the non-negative slope. To satisfy this, [...]
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