LS-DYNA has been a mainstay at Predictive Engineering for roughly 20 years. It has been an amazing journey and on most days, LS-DYNA is the all-time, most favorite code of my simulation existence. But, as we all know, there are moments when the model is not running, the manual must have been written in Greek, un-explicable error messages are flying past you on the screen and basically you are questioning your sanity as the clock tolls 2:00 am in the morning. Nevertheless, in general, 99.999% of the time, you just love the power and flexibility of LS-DYNA. One of our more fun projects was this high-speed cone crusher where big rocks are crushed into smaller rocks. Rock comminution was one of my specialties when I worked for the US Bureau of Mines as a scientist, so this project had a special twist since we now had a chance to make a virtual rock pile and then crush it. The LS-DYNA model used Lagrangian rocks that were then crushed within the rotating, rigid-body cone crusher. Loads were extracted and then applied to a FEA model. The rock crushing model was simply used to create loads for the stress model. As we know in FEA, the three most important things that determine the accuracy of your FEA model are: Loads, Loads and Loads. Yeah – another simulation joke.
George Laird's blog
It is an inside joke among simulation engineers about how long does it take to be considered a “journeyman” simulation engineer. The answer is about five years since it takes that long for your mistakes to catch up with you! It is a brutal profession since everyone is human but the price of failure is especially high when your FEA results are used to build prototypes that cost hundreds of thousands of dollars. Which leads to another saying: “What is the difference between a design engineer and a simulation engineer? A design engineer gets a second chance.” Thus, we were pleased to hear from our client that their composite container passed mobility testing with flying colors. Not only did it pass, the group doing the testing at Aberdeen said that it was the first time that such container had passed all tests at 100% from drop test, rail impact, heavy lift to land transport. If you would like to read about more about our FEA work on this container, please take a look at 026_Jensen, Broad-Spectrum Stress and Vibration Analysis of Large Composite Container.pdf.
The LS-DYNA Conference in Koblenz, Germany was the usual blend of great presentations and even greater social events. The location was beautiful and the Conference was especially well-organized by DYNAmore, Germany (co-sponsored with LSTC, Livermore, CA). Predictive with ENHU, China hosted a morning run event with T-shirts to whoever could show up at 6:45 am. Besides the run, we had our “booth” to support the LS-DYNA North American Team and on the technology side, we presented two papers: Impact Analysis of Polymeric Additive Manufactured Lattice Structures and Transient Dynamic Implicit Analysis for Durability Testing of Bus Seats.