No abstract

The effect of either a single inclusion or groups of inclusions on crack propagation has been studied effectively using symmetric Galerkin boundary elements (SGBEM) and modified quarter-point crack tip elements. Typical results show that an inclusion can decrease the crack-tip stress intensity as the crack approaches an inclusion, followed by deflection of the crack. Interestingly, as the crack extends beyond the inclusion there can also be an amplification of stress intensity. These previous results have shown the great influence the presence of an inclusion may have on crack extension behavior. Here, we examine the influence of an auxetic particle on crack growth behavior. An auxetic material is a material which exhibits a negative Poisson ratio, so they exhibit lateral expansion upon longitudinal tensile loading, and also undergo lateral contraction under longitudinal compression. Such materials can exist in cellular form, or along specific axes in certain crystals. The objective of the present study is understanding the behavior of crack path and predict the crack growth direction in materials reinforced with auxetic particles. We will show the dramatic difference in crack path as compared to particles with positive Poisson ratios by showing results for crack extension in identical specimen geometries reinforced with typical (positive Poisson ratio) particles and auxetic particles.