Modeling the Energy Absorption Characteristics of Wood Crash Elements

Wood is a natural and highly anisotropic material. Therefore, mechanical characteristics of the material depend on the direction and type of the load (e.g. deformation behavior of wood is ductile in compression and brittle in tension). The mechanical behavior of crash elements made of wood material was investigated experimentally and numerically at quasi-static and dynamic strain rates for load-carrying and energy absorption characteristics. For detailed investigations on the mechanical properties of wood, specimens were modeled and *MAT_WOOD (*MAT_143) was selected in LS-DYNA. The process of parameter identification for the *MAT_143 was clarified. In the scope of the experimental studies, quasi-static compression, tension and bending tests as well as dynamic drop tower tests were performed to characterize the material at low and medium strain rates, respectively. It was found that the investigated wood material is highly strain rate sensitive what can be captured by enhancing *MAT_143 by strain rate dependent fracture energy parameters. All material model parameters used in numerical studies were validated according to the experimental results for the *MAT_143. Since wood is a natural composite material, it was modeled with 2D shell element formulation and analyzed with single element simulations by composite material models by referring to material parameters used in *MAT_143. The investigated material models are *MAT_54, *MAT_58 and *MAT_261. The aim is to present a base study to enlighten the damage mechanism of wood for further investigations on the potential of wood-based structural automotive components.