There are several sense switch controls that are available to interactively request LS-DYNA respond to certain pre-defined calls. The well documented sense-switch controls for Explicit calculations are listed below. General Sense-Switches Type Response —- ———————————————————— sw1 a restart file is written and ls-dyna terminates sw2 LS-DYNA responds with time and cycle numbers sw3 a restart…
There are several methods available to interactively termination an running LS-DYNA job. They are briefly discussed here. 1. Sense Switch ‘SW1’ This command is typed by first typing ‘Control-C’ followed by ‘SW1’. This causes LS-DYNA to terminate gracefully by writing all the information from memory to the file system. 2. Creating a file ‘D3KIL’ in…
LS-DYNA is a general-purpose simulation software. This is a good thing for analysts since it provides tremendous flexibility in simulating a wide range of events. The downside to this is the fact that every simulation requires ‘best practices’ to ensure it meets the quality and accuracy requirements of th event that is being simulated. Additionally,…
Came across this excellent tutorial that talks in detail the steps involved in determining the Prony series constants. Determining a Prony Series for a Viscoelastic Material From Time VaryingStrain Data
Several options exist in LS-DYNA to output the energies, stress and strain information for shells, solids and beams depending on the choice of parameters in *DATABASE_EXTENT_BINARY keyword. These are important to understand and enable proper postprocessing of the results when using any post-processors to read in D3PLOT. It must also be noted that increased output…
Starting 971, LS-DYNA allows the direct input of the physical accelerometer mass in the *ELEMENT_SEATBELT_ACCELEROMETER keyword which is lumped equally to the three nodes that is used in defining the accelerometer. This eliminates the need to create additional *ELEMENT_MASS keywords to account for the physical accelerometer mass.
In several simulations, the response of a nodal point (displacement, velocity, and acceleration) is helpful to be output in a user-defined local coordinate sytem. LS-DYNA offers several options to enable the local system output of nodal time history data and here are some examples of it. All nodal time history data is output to either…
Sloshing problems can be simulated using several techniques in LS-DYNA that range from using a simple MAT_ELASTIC_FLUID modeling to a complex ALE or SPH modeling. In this post, a simple problem is set up to demonstrate the fluid representation using ALE element formulation 11 that uses a null material and an EOS (Gruenesium). The sample…
Tiebreak contacts in LS-DYNA have undergone significant enhancements in recent versions. A brief overview is provided in the PDF document below. Special thanks to Jim Kennedy for requesting this and also to Dr. Brian Wainscott, LSTC, for sharing some intricate details about TIEBREAK contacts. Download TieBreak Contacts (PDF)
In many situations, we tend to change the mesh density to study its effect on simulation responses. Two issues things that are seldom addressed are the contact thickness and the mass-scaling which blend in with the true effects of the mesh refinement. As stated in some of the earlier posts, LS-DYNA computes the contact thickness…
