An elliptic inclusion with imperfect interface embedded in an infinite elastic medium.

摘要

This dissertation presents a semi-analytic solution for the problem associated with an elliptic inclusion embedded within an infinite matrix with a homogeneously imperfect interface subjected to simple mechanical and thermal loadings. The interface is modeled as a spring (interphase) layer with vanishing thickness. Under the assumptions of this model the interface bonding will no longer be considered perfect and interfacial displacement discontinuities will be allowed. The role of the imperfect interface parameters on the stress field and average stress is investigated systematically. Both the inclusion and the matrix materials are considered to be homogeneous, isotropic and linearly elastic.; Three distinct studies of composites incorporating imperfect interfacial bonding under the influence of thermal and mechanical loading are presented in this dissertation. The solutions thus obtained illustrate the effectiveness of the present solution methodology.; Complex variable techniques are used to obtain infinite series representations of the stresses induced within the inclusion. The results obtained demonstrate how the (non-uniform) stress field and the average stresses inside the inclusion vary with the aspect ratio of the inclusion and the parameter describing the imperfect interface. In addition, and perhaps most significantly, for different aspect ratios of the elliptic inclusion, we identify a specific value of the interface parameter which corresponds to maximum peak stress along the inclusion-matrix interface or within the elliptic inclusion. Furthermore, the results indicate that it is possible to reduce the thermal stress by inserting a reasonably thick compliant interphase layer under a thermal loading. For the first time, the present work provides a systematic study on the combined effects of an imperfect interface with the aspect ratio of the inclusion shape. The results could be used to evaluate effective properties of composite materials incorporating non-ideal material interfaces and to design these interfaces for minimizing peak interfacial or internal stresses.