Under large compressive forces, elements belonging to either Foams, Honeycombs and Rubbers tend to invert causing numerical instabilities. To avoid such difficulties, which is one of the primary causes of simulation waste (unusable simulation results), a good set of modeling practices are first necessary as outlined in an earlier post .
As an added [...]
Archive for January, 2008
Interior Contact for Foams, Honeycombs and Rubbers to eliminate Negative Volumes.
Published by January 24th, 2008 in LS-DYNA Bytes and LS-DYNA Contact. 3 CommentsReduce D3PLOT File Size for RigidBodies
Published by January 22nd, 2008 in LS-DYNA Bytes. 0 CommentsA simple variable ‘DCOMP’ can be used in *DATABASE_EXTENT_BINARY keyword to suppress unwanted information about rigidbodies to help reduce the size of D3PLOT files. Please note that this feature has no effect if your model has only deformable elements.
Improving Load Balance in MPP-LSDYNA for ALE and SPH
Published by January 17th, 2008 in LS-DYNA Bytes. 0 CommentsIn an earlier post on decomposition and region domains we saw how customized PFILE can be used to improve load balancing. Two new commands “aledist” and “sphdist” can now be included in “PFILE” that allows LS-DYNA to distribute the ALE and SPH information across all processors. This will greatly improve the load [...]
LS-DYNA now offers a modified version of *MAT_CRUSHABLE_FOAM in the form of *MAT_MODIFIED_CRUSHABLE_FOAM . In the new material model, the strain rate effects can be included in the foam a *DEFINE_TABLE . To reduce or eliminate the noise in the evaulation of the new yield stress as a function of strain and [...]
As of today, D3VIEW 2.0beta has been officially released in a closed environment.
Update Due to heavy traffic, the site is currently down. Should be up shortly.
Attached is a simple Excel sheet that can be used to quickly evaluate the timestep calculated by LS-DYNA for solids, beams and shells.
It must be noted that for solid elements, Q is based on the C1 (default = 0.06) only.
timestep.xls
Update
For solid elements using MAT_SPOTWELD, LS-DYNA uses a slightly different method of computing the [...]
Recent Comments