عنوان مقاله [English]
نویسندگان [English]چکیده [English]
In the first part of this paper, the gas tungsten-arc welding process of a thin cylinder made of Al6061-T6 alloy is simulated using 3-D finite element model in the ABAQUS code and the distribution of residual stress is obtained. Temperature dependent thermo-mechanical properties are considered for the aluminum alloy and for simulating the heat source of tungsten arc welding, Goldak's double ellipsoid model is also employed. Based on the finite element results, the value of residual stress is considerably positive around the weld line and HAZ area which can increase the risk of crack initiation and propagation in the weldment zone. Hence, in the second part of the numerical analyses of this research a longitudinal semi elliptical crack is considered in the wall of internally pressurized aluminum cylinder and its mode I stress intensity factor (KI) is determined numerically for different crack geometries. Finally the influence of both residual stress field and internal pressure is taken into account on the value of KI. It is observed that the effects of combined internal pressure and tensile residual stresses around the crack can facilitate required conditions for crack propagation in the analyzed cracked thin cylinder.
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