Particle geometry effects on a stationary crack

Current research interests in materials science are commonly aimed at composites or multi-phase materials because of the beneficial effects that can arise from certain combinations of otherwise unusable materials. An example of this type of combination is the Al-SiC system. Because of the high stiffness, creep resistance and yield strength of SiC the overall stiffness, creep resistance and yield strength of the composite is higher than aluminum. Conversely, the brittleness of SiC decreases the overall ductility to a level lower than pure aluminum. Trade-offs like these can be acceptable for specific applications, but often preclude any successful application. Other examples of this type of material are metal-metal and ceramic-ceramic composites. All of these material combinations have inherent problems related to phase distribution, interfacial bonding, secondary chemical reactions and misfit stresses that must be suppressed if the combination is to be useful. One of the most significant recent advances related to composite materials is the overall increase in yield strength and the suppression has been modeled extensively. The general approach has been to simplify the model of a cracked composite to either the case of a single crack and a circular particle, or a crack and an infinite interface. In ordermore » to more realistically approach composite failure it is of various shapes in a system with general elastic constants. The current project is therefore based on examining the effects of geometrical and elastic parameters in a cracked two-component system. The plane-strain problem that is of interest in this investigation is the influence of the elastic constants and shapes of a particle on the crack-tip stress intensity factor. The model is approached through finite element (FE) calculations and the types of plane-strain elements in use are both 6-noded triangles, and 8-noded quadrilaterals.« less