| Impact resistance is a material's ability to resist the force of a sudden impact. Compared to static loading, materials are more susceptible to a shock force applied over a short duration. Avoiding the catastrophic failure during impact events is the major challenge in the design of impact resistant material. Various approaches have been applied to increase the material's impact resistance. One approach is to combine two or more materials with distinguished physical or chemical properties to produce a new material with better performance without changing the characteristics of the constituents. The proposed study focuses on this approach, specifically, characterizing the toughening and failure mechanism of fiber-reinforced materials or laminate panels for impact and damage tolerance. Two types of materials are chosen for the research work. One is the transparent laminated glassy panel and the other is the natural fiber reinforced composite material, cortical bone. The material properties and failure mechanism were characterized through uniaxial tensile testing (both quasi-static and high strain rate), Charpy impact testing, and drop-weight impact testing. Post-failure examinations were carried out using a scanning electron microscope and bright field microscope. Numerical approaches including traditional finite element analysis method, multiscale modeling technique based on the classical computational homogenization scheme, and XFEM technique for discontinuities were applied to investigate the correlation between impact resistance and damage tolerance of the materials to their microstructure, hierarchical structures, and physical and mechanical properties of each constituent. |
