Finite Element Analysis Of Annular Through-wall Cracks In Inclined Piping Elbows

Fracture mechanics has been used widely in practice with the development of the theories and computer science. It is very important for the pipes being used to make safety estimation in application of fracture mechanics. However, it is very scarce of the fracture parameters to make safe estimation in engineering. Based on fracture mechanics, the inclined weld piping elbows is analyzed by the finite element analysis(FEA) method. The FEA model of annular through-wall cracks in inclined weld piping elbows has been established by the FEA software of ANSYS. The studies give the fracture parameters of stress intensity factor KI in elasticity and J integral in elasticity-plasticity, then convert to the shape factor F and full-plasticity coefficients h1. Including:1. Studying the new method of fracture mechanic in the structure with cracks. It is the bases of farther studies.2. The finite element model has been established by using the FEA software of ANSYS. Based on the EPRI results, it is a validation for the elements used, method of establish model and calculation results.3. The annular through-wall cracks in inclined piping elbows are established by APDL language of ANSYS. The stress intensity factor of KI is calculated under pressure and moment, then is transformed to shape factor F.4. The nonlinear material properties of ANSYS are defined in terms of Voce stiffen theory, using the stiffen-exponent n. The full-plastic results are compiled by the method which is based on the full-plastic J integral of EPRI estimation.5. The full-plastic J integral Jp of the annular through-wall crack of inclined piping elbows is calculated under the different properties of pressure and moment, then the tables of full-plastic coefficients h1 are done.