Multi-Scale Hierarchical and Topological Design of Structures for Failure Resistance

摘要

The goal of this project was the computational and theoretical analysis and synthesis of failure mechanisms in hierarchical structures andmaterials found in biology s structural materials, and the transfer of the results towards the design of hierarchical bioinspired heteronanocomposites. By developing and applying a model that couples atomistic to mesoscopic scales, the major outcomes of this basic research project are: (i) the systematic analysis of deformation and failure mechanisms in biological hierarchical structures (such as bone and spider silk), (ii) the development of designs for heterogeneous materials involving variations in hierarchical structure and topology for damage tolerance, (iii) the development of multiscale models describing the mechanics of materials with disordered heterogeneous distributions of mechanical properties with the potential of uncertainty quantification of fracture properties, and (iv) the development of a hierarchical model that captures deformation mechanisms at multiple hierarchical levels, resulting in hierarchical Ashby deformation mechanism design maps. The project also aims at developing methods to realize physical samples for testing, which reflect the designed geometries. This project addressed a critical frontier in engineering science, the optimization of nanostructure, mesostructure and topological features for failure properties. Whereas structural optimization at larger length-scales has been employed earlier, a systematic investigation of the adaptation of hierarchical nanostructures for failure properties under extreme mechanical loading has not been reported. Moreover, a novel approach offers the possibility of characterizing uncertainties in material properties with the view towards a rigorous risk assessment of the fracture response of advanced hierarchical composites.