Stress Analysis Method Based On Interfacial Phase Properties And Interface Strength Criterion

To keep up with the increasingly stringent and complicated request proposed by engineering practice,bonded material which can combine merits of its components has been widely used.Different forms of bonded materials have a common problem called interface.Interface is actually a concept refined from the modeling of physical complex interphase,and interface failure is indeed the failure of interphase material.To avoid the difficulties caused by tiny geometric dimension of interphase,interface is often dealt as zero-thickness when carrying out theoretical analysis or numerical simulation.But without reasonable equivalent of mechanical properties,traditional methods couldn't build a fully and accurate cognition of interface problem.In fact,due to neglect of interphase material's effect or over-simplification,interface stress analysis method such as classic model and cohesive zone model couldn't provide an accurate evaluation of stress,meanwhile interface failure criterion such as quadratic criterion and parabolic criterion would have a limited implementation range.In this paper,basing on assuming interphase as an equivalent elastic continuum,a new interfacial element which can give an equivalent description of interphase mechanical properties is derived from interface constitutive relation,and the relevant parameters have definite physical meanings.Simulation analysis is performed with commercial FEM software ABAQUS and user subroutine UEL,which agrees well with numerical results of direct physical model.By several further analyzations about structures with different interphase properties,merits and demerits as well as practicable realms of different methods is discussed.Then,basing on failure mechanism of brittle interphase material,inadequacy of traditional interface failure criterion is qualitatively explained and an improvement program is proposed.