Simulation Of High Strength Aluminum Alloy Microscomic Region Crack Propagation

High strength, good process ability, lowly price are outstanding performanceadvantages of high strength aluminum alloy, which makes it become Indispensableimportant structural materials in the many military and civilian aircraft, means oftransport at present, and plays important strategic position in the national defenseconstruction and national economic development. Defects in materials and structures,however, is inevitable, because of the existence of material defects planes, ships,vehicles, nuclear power, chemical industry and ocean engineering etc structures as mainfailure forms under the action of load. The mechanical behavior of materials in smallarea near the crack endpoint on the material fracture phenomenon has played a majordecisive role. Therefore starting from microscopic model, adopting reasonable materialconstitutive relation has very important significance with microscopic region whichcontains defects7055high strength aluminum alloy materials research of ductile crackpropagation.This paper researched two aspects of high strength aluminum alloy microscopicregion crack propagation. On the one hand, establishing the aluminum alloymicroscopic region unilateral crack model, simulated the evolution of the crack front inthe process of crack propagation stress field under a pair of tensile stress. Results showthat in the process of loading, the cracks near the endpoint material softening, stressdrop instead, leading to the crack front stress redistribution, S11instead the maximumstress in the crack appeared on the crack extension is a certain distance from theendpoint. The crack front of equivalent plastic resilience (PEEQ) along with the loadincrease and the sharp rise in; But along the crack line and falling rapidly, instructedmaterial damage happens on the crack front is small area, did not affect the other areas.On the other hand, on the platform of ABAQUS finite element, establishedmultiple material defect microscopic model at293k temperature under complex loadingarea caused by the crack extension related to the numerical simulation. The process ofcrack propagation was analyzed. By comparing the same model under a pair of uniformtensile stress the action of crack formation and results, realized that under complexloading on the structure and material containing defects of harm is very big. And in materials and structures under complex loading when the cracks, it is difficult topredicting crack propagation path and the crack propagation starting point. And thensimulate the crack propagation under different temperature conditions, comparison andthe analysis of the effect of temperature on crack propagation.