Rubber Impact on 3D Textile Composites

A low velocity impact study of aircraft tire rubber on 3D textile-reinforced composite plates was performed experimentally and numerically. In contrast to regular unidirectional composite laminates, no delaminations occur in such a 3D textile composite. Yarn decohesions, matrix cracks and yarn ruptures have been identified as the major damage mechanisms under impact load. An increase in the number of 3D warp yarns is proposed to improve the impact damage resistance. The characteristic of a rubber impact is the high amount of elastic energy stored in the impactor during impact, which was more than 90% of the initial kinetic energy. This large geometrical deformation of the rubber during impact leads to a less localised loading of the target structure and poses great challenges for the numerical modelling. A hyperelastic Mooney-Rivlin constitutive law was used in Abaqus/Explicit based on a step-by-step validation with static rubber compression tests and low velocity impact tests on aluminium plates. Simulation models of the textile weave were developed on the meso- and macro-scale. The final correlation between impact simulation results on 3D textile-reinforced composite plates and impact test data was promising, highlighting the potential of such numerical simulation tools

An orthotropic multi-surface elastic-damaging-plastic model with regularized xfem interfaces for wood structures

Wood is an extraordinary natural composite material exhibiting a pronounced orthotropic behaviour, and markedly different properties along the parallel and transverse-to-the grain directions. It displays a strongly non-linear response, almost elastic-plastic under compression and elastic-damaging under tension and shear. Restoration and development of smart wooden based elements are gaining an increasing interest in the building industry. In this context, the computational challenge is to develop numerical constitutive models that account for the complex, strongly non-linear, nature of wood behaviour. In the present contribution, we develop a novel constitutive model obtained by coupling a non-smooth multi-surface plasticity model for compressive failure modes, with an orthotropic damage model for ten-sile/shear failure modes. Joints are modelled with a regularized version of the eXtended Finite Element Method (XFEM) that allows to model the development of the crack process zone, while ensuring mesh-size independent results and a smooth continuous-discontinuous transition. It is shown that the obtained numerical results satisfactorily fit with experimental data