A gray-scale mapping method to consider locally varying properties for wood forming simulations

Abstract

Automotive interior components in upper-class vehicles are often made of wood veneer sheets that are subject to a forming process [1]. Due to the anisotropy and inhomogeneity of the material caused by the development of annual rings during the growth of the tree, establishing a stable production process based on trial-and-error forming tests is time-consuming and costly [2]. Hence, numerical methods for simulating the forming process are in high demand to support the development of feasible trim part geometries. The key for reliable process simulations of wood-based materials is the consideration of the variability of material properties. In this paper, the authors present a method to account for the locally varying properties of early and late wood in finite element simulations using a gray-scale mapping procedure. The method was introduced in [3] and was implemented in the software tool Envyo® [5]. The developed approach, which consists of a gravity loading step and a forming simulation with *MAT_LAMINATED_COMPOSITE_FABRIC (*MAT_58) in LS-DYNA [4], is validated using the example of a palm rest of the Mercedes-Benz X167 series. Furthermore, the necessary steps and assumptions for material data calibration will be demonstrated.