LS-DYNA Meshfree Interactive Adaptivity and Its Application

The meshfree adaptive method has been developed and widely used as an important tool to deal with large topology change with severe local deformation in the application of 3D metal forming analysis. However, due to the complexity of material deformation, it is impractical to predefine the adaptivity before the actual analysis is performed. The interactive adaptivity will be an alternative to dynamically detect distortion and maintain the quality of meshfree discretization. In this work, we are going to present a new development on meshfree interactive adaptivity. Several control indicators are introduced to measure the local distortion in discretization as material deforms. When one or more indicators are beyond certain tolerance, which indicates the occurrence of severe shear deformation, large volumetric change, or unbalanced nodal distribution, meshfree interactive adaptivity is triggered. The user defined tolerance is carefully adjusted according to the history of material deformation to avoid the over-activation of interactive adaptivity. Several numerical examples will be presented to demonstrate the advantages of interactive adaptivity and compared to the traditional approach.