Arbitrary Lagrangian-Eulerian (ALE) in LS-DYNA is an Eulerian method with the background mesh moving with materials. The momentum equation is solved by explicit time integration that includes the Lagrange time step and the advection counterpart. Multi-materials in each background element are represented by their volume fraction, where they have the same strain rate but different stresses. The material interface is reconstructed based on the multi-material information of elements. Fluid-structure interaction (FSI) is developed to couple structure mesh and ALE mesh in various conditions including separation and overlapping.

The new structured ALE (S-ALE) solver is dedicated to solve the subset of ALE applications where a strctured mesh is appropriate. As expected, recognizing the logical regularity of the mesh brought a reduced simulation time for the case of identical structured and unstructured mesh definitions.

  • S-ALE highlight [1]

    • Same theory as the conventional ALE in LS-DYNA

      • Advection (remapping)​

      • Interface reconstruction

      • FSI to couple with Lagrangian structure

    • Structured background mesh

      • Faster searching and sorting algorithm

      • ​New automated mesh generation

    • More compact and efficient solver

      • Highly scalable parallel computation

    • More stable and user-friendly

  • Current implementation [2,3]

    • Convert models from ALE to S-ALE

    • S-ALE background mesh

      • Deletion​

      • Merging

      • Trimming

      • Motion

    • Multiple mesh and contact

  • Keyword [4]

    • *ALE_AMBIENT_HYDROSTATIC

    • *ALE_STRUCTURED_FSI 

    • *ALE_STRUCTURED_MESH

  • Application​​​ [5]

    • Projectile-target penetration

    • Mine blast and impact on a structure

    • Detonation under vehicle armor

    • Tank sloshing and impact

    • Extrusion

    • Bird strike

    • Consumer product drop test