Analysis Of The Interface Crack Problems Using Universal Weight Function Method

It often occurs that the interface cracked bodies withstand mechanical and thermal impact loadings in engineering practice. Most cracks presented in engineering practice are three dimensional. At present, the prevailing method for dealing with such problems is the interaction integral method. Unfortunately, this method has a disadvantage which is that the repeated determinations of stress field for individual time instants will be needed to determine the variation of transient stress intensity factors which can be calculated based on the stress field or displacement field and then the computational efficiency has been reduced. In order to complete the safety evaluation of engineering structures subjected to mechanical and thermal impact loadings timely and accurately, the universal weight function (UWF) method is applied to analyze the problems that two dimensional and three dimensional interface cracked bodies withstand mechanical and thermal impact loadings in the present paper. The major work of this dissertation as follows:1. Finite element implementation of the UWF method for two dimensional Mode I, Mode II interface cracks subjected to thermal and traction loadings is given in this paper based on original study; The basic equation of the UWF method for three dimensional Mode I, Mode II and Mode III interface cracks subjected to thermal and mechanical loadings is given in this paper based on Betti’s reciprocal theorem, furthermore, the finite element implementation of the UWF method for three dimensional interface cracks subjected to thermal and traction loadings is presented based on multiple virtual crack extension technique.2. The research on secondary development technique of the finite element software ANSYS and ABAQUS which can be used for the extraction of original data has been done, furthermore, the development of program system has also been completed based on the numerical integral formula used for the calculation of stress intensity factors of two dimensional and three dimensional interface problems. 3. Numerical results show that the UWF method is of good accuracy and satisfies the engineering application demand. The influence of different ratios of material properties, different crack lengths and different material thicknesses on the histories of distributions of transient stress intensity factors with respect to time has been studied, and some helpful results for the project have also been given.