There are two different methods that are available in LS-DYNA to treat nodes impacting a rigidwall (also referred as stonewall). The first method, which is the default method, is the constraint type that is used for all deformable nodes impacting a rigidwall. The second optional method is the penalty approach that is used for [...]
Archive for February, 2007
Choice of Rigidwall Treatment
Published by February 27th, 2007 in LS-DYNA Bytes and LS-DYNA Contact. 2 CommentsBest Practices for Building Flexible Models with Reduced File Sizes
Published by February 26th, 2007 in LS-DYNA Bytes. 2 CommentsAs LS-DYNA model sizes continue to grow, there is a greater need to reduce the file sizes or rather the model footprint. If good modeling practices are maintained, there can be tremendous file size reductions even for large models and this post will review some of the best practices aimed to reduce the model input/output [...]
Transient Removal of Initial Penetrations Using DPRFAC Parameter for SOFT=2 Contacts
Published by February 23rd, 2007 in LS-DYNA Bytes and LS-DYNA Contact. 12 CommentsBeginning LS-DYNA versions 971, a new option for SOFT=2 contact called DPRFAC in Optional Card ‘C’ in *CONTACT keyword allows transient removal of any initial penetrations. This option is useful to quickly zero out any initial penetrations rather than just to remember them. The following figure shows how the effective penetration that is used to [...]
A simple ‘C’ program is included to extract the processor based timing information from D3HSP file and output load balance summary. Future versions of MPP-LS-DYNA may include more information such as the summary shown below.
Usage: load_balance_checker d3hsp_file_name {threshold_factor}
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Load Balance Diagnosis for MPP LS-DYNA
Author: Suri Bala, Livermore [...]
MPP and Deformable to Rigid Switching
Published by February 19th, 2007 in LS-DYNA Bytes and LS-DYNA MPP. 0 CommentsYou may have read the previous post on deformable to rigid switching which works by turning a predefined set of deformable components into a rigidbody at a user-defined time to save on element processing costs. This may not necessarily be true when running using any of the MPP-LSDYNA executables since the domain decomposition routines do [...]
Load Balance in FMVSS 207/210 Simulations for MPP
Published by February 16th, 2007 in LS-DYNA Bytes and LS-DYNA MPP. 0 CommentsAnalyses involving automotive seat designs for loadcases such as FMVSS 207/210 has shown some poor load balance on compute nodes when using the default decomposition in MPP LS-DYNA. In FMVSS 207/210 type simulations, the computationally expensive portion of the model lies at the seat and its immediate viscinity while the rest of the model [...]
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