Development of a Unit Cell Model for Structural Metal Sheets using *CONSTRAINED_MULTIPLE_GLOBAL

In this paper a thin structural metal sheet is researched in regard to crashworthiness as energy absorber and a Finite Element model based on the theory of Representative Volume Element is generated. Special attention is spend to the global constraining with the LS-DYNA keyword *CONSTRAINED_MULTIPLE_GLOBAL. It relates single displacement components of any degree of freedom (DoF). Therefore, an academic example is shown and the numerical analysis is explained. The example is restricted to the theory of linear Finite Element Method, containing the formulation based on the variation of displacements, the weak form of differential equations (which leads to the Principle of Virtual Work) and the weighting and shape functions defined by Bubnov-Galerkin. Furthermore, the benefit of reducing the system of equations and the speed-up of computation time based on the constraining of DoFs is pointed out and demonstrated by the present structural metal sheet. In addition, the functionality of a self-written python routine is exemplified, which simplifies the procedure of constraining for large three-dimensional problem domains.