LS-DYNA Examples Blog by Student Qui

Update The blog no longer seems to exist. I recently came across a nice blog written by QUI. It is remarkable that he is willing to share examples and his experiences in LS-DYNA. The broad spectrum of LS-DYNA applications can never be fully covered by a single blog or a small set of publications. It…

April 30, 2010 | by

Unloading in MAT_FABRIC (MAT_034)

This is a post by Guest Author Satish Pathy who works full time for LSTC In *MAT_FABRIC, element formulation 4 & 14 will allow you to input unloading curve for the material. Recently in a model it was noticed, that when a large compressive stress develops in the fibers, lsdyna would release some of these…

April 15, 2010 | by

Mass scaling for MAT_SPOTWELD elements

Deformable spotwelds modeled using beams or solids elements can invariably limit the global timestep due to its small dimensions. LS-DYNA provides two methods to scale the spotweld timestep. The first method is the well-known global mass-scaling using DT2MS in CONTROL_TIMSESTEP. When DT2MS is non-zero (usually a negative number), the density of the spotwelds are modified…

April 5, 2010 | by

Shell, Solid and Beam Formulations for Explicit and Implicit

Control cards are often handy to overwrite local values. A good example would be if we need all parts to use a certain element formulation THEORY which is specified in *CONTROL_SHELL. As with any global control cards that manipulate local values, the global values specified in *CONTROL keywords are used ONLY if the local values…

February 22, 2010 | by

Modeling rigid bodies

LS-DYNA allows the modeling of rigid-bodies by assigning any part with the MAT_RIGID material law (MAT_020). This is by far the most easiest method available when compared with all finite element codes. When using MAT_RIGID, there are three distinct ways to model a rigid part and they are briefly explaine below. 1. Finite Element based…

January 13, 2010 | by

Significance of IGAP Parameter in *CONTACT in Implicit Analyses

In traditional explicit analysis, there is no convergence criteria that is checked for each time step. However, in Implicit calculations, incremental displacements are evaluated such that a displacement norm and the energy norm are within a pre-defined tolerance before convergence is assumed to be obtained. This is the so-called iterative scheme in Implicit Non-Linear Analyses…

September 1, 2009 | by