Came across this nice document that talks about the strains and stress computations used in many nonlinear finite element codes. If you know the author of ths material, please do let me know. You can also find the entire set of materials here
I posted a detailed document on the TIEBREAK contacts. Here are a few things that I noticed after the I wrote the article. 1. Scale down the penalty stiffness down to 0.1 if you see instability. 2. It is important to have the two surface to be “just in contact” and not “too far” or…
In an earlier post, we saw how *CASE keywords can help us perform sequential and sequential+dependent simulations. But here I want to talk a little more about the LSCASEDRIVER program itself. LSCASEDRIVER is a simple yet powerful utility that is sometimes built into the LS-DYNA executable, but it can also be used in a standalone…
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…
Encryption has been around for several years but it finally comes to LS-DYNA in the form of GPG encryption which can be used at no additional cost to encrypt LS-DYNA input files to protect important proprietary data such as material definitions. Any portion of the input file can also be encrypted in multilple blocks of…
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,…
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…
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
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…
