Archive for the 'LS-DYNA Bytes' Category

Free Limited LS-DYNA Version to Assist Displaced Workers

LSTC has introduced a free limited LS-DYNA version for U.S. unemployed LS-DYNA users as a result of the current poor economic conditions. A free LS-DYNA course may also be introduced in the coming months. Please contact Marsha Victory at 925 449 2500 or send her an email at marsha at lstc dot com.

Multi Solver Run in LS-OPT

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 [...]

Packing LS-DYNA Input Files for Easy Distribution (v1.1a)

In 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 [...]

Damage modeling using GURSON

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

It 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

In 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, [...]