In mesh independent deformable spotwelds (see here ), the actual spotwelds are represented using either beams or solids (single or cluster). The nodes of the beam or solid element representing the spotweld are then tied to the sheet metal using a tied interface (TIED_SHELL_EDGE_TO_SURFACE or TIED_NODES_TO_SURFACE). The forces experienced by the beam are the result…
You may have seen this popular message that is printed out by LS-DYNA for every simulation. The LS-DYNA time step size should not exceed 0.456E-06 to avoid contact instabilities. If the step size is bigger then scale the penalty of the offending surface Lets review this to understand a little more. As we know, Explicit…
A few questions recently from some users while teaching a class prompted me to write this overview regarding the data output, particularly for shell elements, into D3PLOT and how the post-processors plot them. The brief overview is listed in the form of list items for a quick read. 1. Element output are always element centered…
Just wanted to post some stats (courtesy http://www.statcounter.com) we gathered for the blog. It has been extremely gratifying that readers come back to look for information. We want to thank all our readers, and we hope to continue providing useful posts that help LS-DYNA users worldwide. (Click image to enlarge)
I am glad to write that Sven Holcombe from Japan will be providing us a brief first-hand coverage of the Japan LS-DYNA Conference that is going to happen on Oct 30 & Oct 31! Please thank Sven when you get a chance. Details of the conference can be found here 2007 Japan LS-DYNA Conference Thanks…
Recently, I have been assembling models outside of any pre-processors and found that the use of Makefile can often be very helpful in putting together models on the fly provided you have a good process of storing the models in subsystems. A simple example is show below. # Comment starts with a pound sign #…
In web technology, it is a common practice to build applications that “share nothing”. For example, if a web application is running on a web server, and you need move the application to another machine, it is extremely simple to do this if the app does not use data on the machine its running on.…
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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…
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
