Research On Technology Of Thermal Weight Function Method Based On ABAQUS

Due to the stress singularity at the crack tip, the stress intensity factor can describe the strength of stress field at the elastic body crack tip. The stress intensity factor can be used as the fracture criterion to measure structural fracture.The weight function is a universal function, which is dependent only on the body geometry and boundary conditions, and is independent of load case. The TWF method is especially suitable for determining the variation of transient stress intensity factor of a cracked body subjected to thermal shock. TWF is independent of time during thermal shock, so the whole variation of transient SIF can be directly calculated through integration of the products of TWF and transient temperature and temperature field, thus avoided repeated finite element calculations of the distributions of stress fields for individual time instants.In this thesis, the technology of TWF method used for I mode and Ⅰ-Ⅱ mixed mode crack case under thermal shock is developmented based on ABAQUS.Firstly, the fundamental formula and principles of the thermal weight function method are derived. The types of FEM analysis and the related data output are established based on ABAQUS application program.Secondly, secondary development of ABAQUS used by the scripts program has been studied. The analytical file is created、edited、operated by Python scripts. The data operation and the solution of SIF are used by Fortran language. In case of I mode and Ⅰ,Ⅱ mixed mode crack, The program code of the thermal weight function method is developed used for the calculation of SIF.Finally, the calculation of SIF through thermal weight function is used for mechanical load and thermal shock cases, and the results are compared by ABAQUS thermal stress analysis. It is shown that:the program code is effective and the method of thermal weight function has high efficiency and accuracy.