It is important to understand the damage events in composite materials at the micro level, model elastic properties, and understand phenomenological aspects of strength. Development of an accurate representation of these phenomena at the local level is difficult but pioneering work was done by researchers at Virginia Tech. This thesis builds on the previous efforts at Virginia Tech where the experimental and analytical models were improved to include high fiber volume fractions. Experimental techniques were developed to achieve a controlled fiber fracture at a predetermined location and then measure the over-strain experienced by the neighboring rods. A finite element model was used to validate the micromechanical analysis. Quantitative measurements of perturbed strain fields were measured with embedded strain gages which were then compared with the finite element results. / Master of Science

During this master thesis a crushing material composite was developed in order to determine if a specific design consisting of a pointy hard phase with a ductile phase in between can reduce the load needed to crush stone and therefor decrease the energy consumption during stone crushing. The steel hard phase (ASP 2012) was printed using an additive manufacturing method called selective laser melting (SLM). A process parameter optimization was performed in order to achieve a dense material and a pre-heated building platform was used to prevent cracking. The hard phase designs were printed and then filled with bronze (JM3 and JM7). The composites and steel references were tested by placing a stone on each sample and applying pressure until the stone broke. After the tests, the loads and the deterioration of the samples was analyzed. The results showed that it was possible to print the hard phase, but some defects like micro cracking were hard to eliminate entirely. Several methods were tested to cast the bronze but the most suitable during this project was melting of the bronze in an induction furnace with vacuum atmosphere. The results from the crushing simulations showed that there was a small difference between the references and the developed macro composites. The composites began to crush stones at lower loads than the references. Nevertheless, due to a large dispersion of the results a statistical difference could not be established.