Eigensolution Technology in LS-DYNA

LSTC has been adding additional eigensolution technology to LSDYNA. For several years LSDYNA has a Block Shift and Inverted Lanczos Eigensolver in both SMP and MPP implementations. But this capability did not cover the full spectrum of applications. We have supplemented the Lanczos solver with a Power Method solver for implicit mechanic problems using the Inertia Relief Feature. As we have been adding unsymmetric modeling features through materials, elements, and contact, we have added an eigensolver based on ARPACK for such problems. Important applications for the unsymmetric eigensolver is rotational dynamics and brake squeal analysis. We have developed an implementation of AMLS (Automated Multilevel Substructuring Method) for applications such as NVH that want hundred, even thousands, of eigenmodes quickly which are willing to have a less accurate solution compared to the Lanczos eigensolver.