George Laird's blog

LS-DYNA Blast Analysis of Large Generator Housings

For more than 15 years, LS-DYNA FEA consulting services have been an integral part of Predictive Engineering. In a recent project, we investigated the blast resistance of several large generator housings. The blast pulse was determined by ConWep calculations given the TNT charges and distances from the housings.

Although LS-DYNA has several built-in methods for simulating blast loading (e.g., *LOAD_BLAST_ENHANCED and *PARTICLE_BLAST), most far-field air blast load calculations of exposed structures can be done as shown in the graphics below. Results from this investigation allowed our client to decrease the weight of their design to such an extent that analysis costs were easily recovered, and that the housings would meet all infrastructure protection requirements at the base. 

LS-DYNA Blast Analysis of Large Generator Housings 01

LS-DYNA Blast Analysis of Large Generator Housings 02

Cooling Analysis of Composite Mandrel using STAR-CCM+

STAR-CCM cooling analysisModern jet engines are getting bigger and also lighter. For example, years ago it was common to use titanium or stainless steel as blade-out containment materials. These large diameter and thick rings can now be replaced by modern carbon fiber composites; however, manufacturing large diameter composites with tight tolerances is difficult. One of the key challenges is maintaining tight tolerance during heating (curing) and cooling (mandrel removal) process. In a recent CFD project for a Tier 1 aerospace manufacturer, we used STAR CCM+ to simulate the thermal-flow process of cooling the composite mandrel down to room temperature. STAR was particularly suited for this project given its advanced polyhedral meshing technology coupled with a fast MPP thermal-flow solver (High Performance Computing (HPC)). Results in this CFD consulting project were verified against prior experience and hand calculations.
 

A Roadmap to Linear and Nonlinear Implicit Analysis in LS-DYNA

Below is a condensed presentation of our paper "A Roadmap to Linear and Nonlinear Implicit Analysis in LS-DYNA" that we presented at the 11th International LS-DYNA User's Conference in Salzburg, Austria on May 9-11, 2017.

Here's the Abstract: The default LS-DYNA settings are tailored for running large explicit analyses. For new and even experienced users, it can be challenging setting up an implicit LS-DYNA analysis to match analytical solutions or other standard implicit FEA codes. For example, the default element formulations are based on single-point integration whereas implicit analyses benefits from full-integration. A series of example problems are provided that will allow the simulation engineer to exactly match industry standard implicit codes (complete keyword decks can be found at DYNAsupport.com). Along with these example decks, CPU-scaling results will be presented for each implicit analysis type from linear to nonlinear.

We hope you enjoy it as well as our soundtrack selection.

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