ALE/FSI AirBlast Modeling: On the Way to One Billion Elements

The Arbitrarian Lagrangian Eulerian (ALE) method of LS-DYNA® software is the best actual solution to perform AirBlast simulation. Indeed, thanks to its coupling method (ALE/FSI), it allows to the user to model complex blast waves interaction with Lagrangian structures. Today, due to hardware advances (the computer power highly increased) and LS-DYNA technology enhancement (ALE Mapping, MPP), it becomes possible to consider models with a very large volume of air, while keeping a good accuracy with a small element size. These new possibilities lead to a quantity of elements never reached before, for which LS-DYNA and LS-PrePost® had to adapt. In this paper, based on work realized with the help of LSTC, we will explain what exactly are the issues of modeling an ALE/FSI model with more than 100 million elements and what solutions were found. We will present some facilities to pre-process such a big model, like the new LS-PrePost “Long Format” or an innovative way to create ALE mesh using a new LS-DYNA keyword. We will also discuss about other important points concerning MPP decomposition, memory needs and post- processing, in order to give LS-DYNA users a complete overview of the ins and outs.