I am glad to announce that the latest version of LS-DYNA will support the use of *DEFINE_CONTACT_VOLUME in any *SET_{OPTION}_GENERAL keyword. As most of you know, *DEFINE_CONTACT_VOLUME offers many advantages over *DEFINE_BOX such as definition in a local system and multiple shapes such as sphere, ellipse, box, and cylinder. With this support, my earlier post…
Recently, I was teaching a class for Black & Decker, and one of the students, Kevin, was taking notes that I thought captured my lecture quite well. I asked him to provide a scanned copy which is included here for others who may find it helpful. notes.ppt
Sven Holcombe of JARI sent us this great presentation summary that covers some of the paper presentation at the 2007 Japan LS-DYNA Conference. Its has been a lot of work for Sven I am sure and its greatly appreciated for his effort. Thanks a lot, Sven. (I removed the preview since the loading time of…
In 2D shell elements, the stress in the normal (fiber) direction is iteratively reduced to zero to meet the plane-stress condition. The strains are however nonzero in the fiber direction and will be linear though the thickness. Under membrane straining, LS-DYNA allows an option to account for the reduction in the shell thickness in the…
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…
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…
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…
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)
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 #…
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…
