Analysis of indentation cracking in brittle solids.

摘要

This thesis deals with the indentation cracking problem in brittle solids. First attention is focused on the elastic contact analysis between a Vickers indenter and a half space. Influence matrix and fast Fourier transformation methods are used to obtain the contact pressure between the Vickers indenter and material surface. Submodeling utilizes the special properties of Vickers indentation. The agreement between the results of these two methods validates use of the resulting stress field in subsequent analysis of indentation induced fracture. Second, the stress field in the half space caused by the indentation loading and an approximation to plastic deformation is provided. Detailed analysis of the median and radial cracking patterns in the loading and unloading cycle has been conducted based on this model. Very good agreement between the results of numerical analysis and experimental observations has been reached. Lastly, the lateral cracking phenomenon around the scratch caused by sliding indentation in brittle solids is analyzed using the two-dimensional finite element method. The resulting numerical calculations show that the sliding blister field is consistent with observation of lateral crack growth.