Modeling cracks and inclusions beneath surfaces under contact loading
Kun Zhou (Nanyang Technological Univ.), Wei Rongbing ()
Prager Medal Symposium in honor of George Weng: Micromechanics, Composites and Multifunctional Materials
Wed 10:45 - 12:15
MacMillan 117
Surface damage in contact such as wear and plastic deformation not only affects surface performance but also lead to material failure. It is critical to predict the surface damage for the design of advanced functional materials. A real surface not only has roughness but also contains micro-defects formed at or beneath the surface during the material manufacturing process. The micro-defects can be homogeneous inclusions, inhomogeneous inclusions, voids or cracks. A homogeneous inclusion is defined as a region that has the same elastic modulus as its surrounding matrix but contains eigenstrain, a generic term referring to inelastic strain such as plastic strain, misfit strain and thermal strain. In contrast, an inhomogeneous inclusion has different material property than the matrix and it may or may not contain eigenstrain. The surface damage can be induced and worsened by such micro-defects. This paper presents a unified new framework for modeling damage to real surfaces in contact. The framework is based on a general solution for multiple inhomogeneous inclusions and cracks beneath a surface under contact loading. The solution takes into account all the interactions between the subsurface inclusions and cracks and the surface contact loading, thus providing an accurate description of the surface deformation and pressure and subsurface stress field. The framework can be used to model various types of surface damage phenomena. For example, a plastic zone can be regarded as a homogeneous inclusion and thus plastic deformation can be conveniently modeled by the framework. The framework can also model plastic zone evolution and crack propagation by incorporating plastic flow rule and cracking criteria.