Multi-Scale Approach to Investigate the Tensile and Fracture Behavior of Nano Composite Materials.

摘要

This program is concerned with the effects of nano size particles on the tensile and fracture behavior of particulate composite materials. The program's basic approach involves a blend of experimental and analytical studies. In general, mechanisms and mechanics involved in the damage process and cohesive fracture are emphasized. Special issues that will be addressed are: (1) To what extent and by what mechanism do the nano size particles affect damage initiation and evolution processes, deformation processes, and crack growth behavior; (2) What are the deformation and failure mechanisms on the meso and the macro levels; (3) How do the nano size particles affect the characteristics of the interphase between the particle and binder; and (4) what is the role of the interphase properties in damage initiation and evolution processes. The objectives of the proposed research are to (1) obtain a fundamental understanding of the effects of nano size aluminum particles on the constitutive and crack growth behavior of particulate composite materials, (2) investigate the effects of aluminum particle size on deformation mechanism, damage process, hysteresis, and fracture strength under a constant strain rate condition, (3) determine the role of the interphase in damage initiation and evolution processes, (4) determine the deformation and failure mechanisms on meso and macro scales, (5) develop a statistical based technology to evaluate the inherent material quality, and (6) provide guidance for developing high strength solid propellants containing nano size particles.