Explicit Analysis: A tool for Explosions, Free Fall Lifeboats, and more

We have extensive experience in Explicit Analysis utilizing AUTODYN™ and LS-DYNA™

Projects have been in the areas of Explosions and Ground Shock (AUTODYN, LS-DYNA), Fluid-Structure Interaction involving Solids, Fluids, and Gases (AUTODYN), Mechanisms (AUTODYN), Personnel Mines (LS-DYNA), and Dropped Objects (AUTODYN).

Unfortunately, much of the work has been performed under non-disclosure agreements and we can not publish what we have done.

In particular, we have been doing simulations for SRSA, the Swedish Rescue Services Agency (Svenska Räddningverket), and some of the reports based on our work ccould previously be found on SRSA’s website.
However, The Swedish Emergency Management Agency, the Swedish Rescue Services Agency, and the Swedish National Board of Psychological Defence all ceased operations and closed down on 31st December 2008. Instead, on 1st January 2009, a new, consolidated authority, the Swedish Civil Contingencies Agency (MSB) became functional.
It may be that the reports become available as soon as MSB's new website is finished.

Stabilisator Tanks and Moonpools
Based on our success with Explicit analysis for Free fall Lifeboats, we have developed new procedures for AUTODYN that allow us to study how Stabilisator Tanks and Moonpools work in ships. The nowel consept couples sea state and its influence on the ship, the effects of water in moonpool, and the movement of water in stabilisator tanks. Picture shows breaking wave in stabilisator tank (after sudden change in sea state).

Free Fall Lifeboats
Recently, we have been simulating Free Fall Lifeboats (in Norwegian: "Fritt Fall Livbåt" or "Stuplivbåt") being dropped from various heights by means of utilizing the Explicit Analysis capabilities in AUTODYN.
Based on the outcome of the simulations, we have invented a mechanism that is cheap, easy to implement, and reduces accelerations and the loading on the life-boat by a very significant amount. testing has shown that the accelerations can be reduced with as much as a factor 4.4 (!). We have applied for an international patent for the mechanism.

Gas Release in Water
For Offshore Applications, Explicit Analysis can provide rather useful insight into problems that can not be adequately assessed by Navier-Stokes Solvers integrated with Structural Analysis software. A typical example would be the sudden release of gas under high pressure. Another example would be underwater impact. We have extensive and unique expertise in solving these classes of problems. Please contact us for more information.

Riser Break and Blowout with Gas Release in Water
Based on AUTODYN, we have developed a very unique concept for studying the break of studying the Effects of Riser Breaks, including Large Movements accounting for Gas Impulse and Drag Forces. For more info, see here.

Converting Un-Structured Grids to Structured Subgrids
We use ANSYS™ for the generation of the AUTODYN and LS-DYNA meshes utilizing our "Index Spacer". "Index Spacer" is a tool that converts unstructured grids into sets of structured sub-grids. A second generation of "Index Spacer" is now available. "Index Spacer" will partition an unstructured grid into a minimum number of subgrids as a default, but there are many options letting the user control how the original unstructured grid is partitioned. If you are interested in testing “Index Spacer”, please contact us. Note that “Index Spacer” will work with any grid (or mesh), it is not tied to ANSYS or any other software.