Vertical Class Bimaterial Interface Crack Tip Stress Analysis

With the rapid development of engineering technology, composite materialsare used in production widely. In recent years, with the depth research ofcomposite materials, interface singular stress field has attracted great attentionof many scholars. The research of the stress field of isotropic bi-materialinterface end and orthotropic bi-material interface end has achieved someimportant results. But the fracture of bi-material occurs not only from theinterface, thus obtain the analytical expression of stress field near the interfaceend is very important. And the researches of the crack tip of stress field aboutthe isotropic bi-material interface as well as the anti-plane interface end havemade some achievements, but for the researches of stress field of crackperpendicular to an orthotropic bi-material interface in this area is still rarelyespecially the crack located entirely in a material in a distance with interface.Composite material is a combined material and its damage occurs from near theinterface usually. Therefore, the research on mechanical properties and influencefactors of the interface of composite material has importance significance forstrength and reliability evaluation of combined material.In this paper, we construct a model-I and model-II crack perpendicular totwo kinds of orthotropic bi-material interface. By using Fourier integraltransform, the displacement and the solution of stress field form crack tip isgiven, also the stress intensity factor is given. By introducing auxiliary functionand using the corresponding boundary conditions, the problem is transformedinto the first category containing Cauchy nuclear singular integral equation andthe specific methods is given. Defied the stress intensity factor of the model, andthe correctness is given. When the parameters of two orthotropic bi-material arethe same, the results of the stress intensity factor we get is as the same as theknown reference. And provides a theoretical basis for the orthotropic biomaterialstructure optimization design.