Viewing Contact Frictional Energy

When friction is enabled in contact treatment using static or dynamic fricition coefficients (FS, FD in *CONTACT), the energy dissipated due to friction can be recorded and visualized. The parameter that tells LS-DYNA to ouput the frictional energy is FRCENG in *CONTROL_CONTACT. FRCENG by default is set to 0 to ignore the recording and output…

December 14, 2010 | by

Tensile failure in Low Density Foams

When modeling low-density foams, it is important to consider potential failure under tensile loading. In LS-DYNA, the most popular constitutive material model is MAT_LOW_DENSITY_FOAM (MAT_057), in which the default treatment of foams under tensile loading is linear with no failure. The Elastic Modulus (Emax) in tension is computed to be the max( max(slope of the…

December 14, 2010 | by

Hybrid LS-DYNA

With the recent growth of multi-core chips, scalibility of pure MPP LS-DYNA beyond 128 cores has shown degration due to several factors including latency and network communications. LSTC has recently developed a new code named “Hybrid LS-DYNA” that provides sustained scalibility for large number of cores and also yields digit-2-digit repeatibility when changing the number…

October 21, 2010 | by

Mat224 Keyword Manual Pages

Several of you requested the manual pages for the newly developed tabulated Johnson-Cook constitutive law now labeled as MAT_224. Here are the three pages of the keyword manual. MAT224 All Pages [ Click the image to enlarge] MAT224 Page 1 [ Click the image to enlarge] MAT224 Page 2 [ Click the image to enlarge]…

October 20, 2010 | by

LS-DYNA Material Selector

Finding a good material law can sometimes be a daunting task even for experienced users. To facilitate a quick review of possible material laws for a given material criteria, a LS-DYNA Material Law Browser was created for personal use and I hope its useful for others. Please send any feedback you may have at info@d3view.com

October 5, 2010 | by

Shell Local Material Axis Definition for Orthotropic Material

Most orthotropic material rely on the parameter AOPT to define the change/update the default material axes defined by LS-DYNA. The default axis for every shell element is based on the order of the node numbers if INN=0 which is then based on N1-N2 and the cross-product of N1-N2 and N1-N4. The default material axes may…

October 5, 2010 | by

LS-DYNA and D3VIEW helps BYU Students build PACE F1 Car

Over six months ago, two students, Rob Moncur, pursuing his MS, and Satyan Chandra, pursuing his UnderGraduate Studies, in Brigham Young University (BYU) set out on a path to build a LS-DYNA crash-analysis model of the PACE F1 car in under 8 weeks. Under the guidance of their professor, Dr. Greg Jensen, and with minimum…

August 28, 2010 | by

Thick shells in contact

During one of my recent trips, a question was raised about how LS-DYNA treats thick shells in contact in particular if the contact would detect the surface sides. This simulation Thickshells in contact shows that LS-DYNA treats the thickshells as solids in which all external (free) surfaces are included in the contact. ERODING contact would…

August 13, 2010 | by

Visualizing Dynamic Relaxation Convergence

Understanding the rate of convergence when employing Explicit Dynamic Relaxation can be very useful to track model sensitivity and to solve convergence problems. d3VIEW now has support to auto-extract the convergence information after a simulation is completed. It also processes DR graphics data to identify points of divergence. Attached is a snapshot from a recent…

July 29, 2010 | by