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Numerical Simulation Of Temperature Field In Laser Deep Penetration Welding For Aluminum Alloys

Posted on:2007-08-25Degree:MasterType:Thesis
Country:ChinaCandidate:Z J XiongFull Text:PDF
GTID:2121360212959363Subject:Materials Processing Engineering
Abstract/Summary:PDF Full Text Request
Aluminum alloy is regarded as one of environmental protection materials and preferred in the fields of automobile manufacture and aviation with its advantages. The technology of laser deep penetration welding (LDPW) for aluminum alloy has become a main reason which impedes the application of aluminum alloy in these fields. The high reflectivity and thermal conductivity of aluminum alloy and compact oxide film (Al2O3) on its surface make its weldability of LDPW poor. The existence of these problem in LDPW for aluminum alloy greatly restrictes the scope of the application of welding technology. Therefore,it is of great significance to understand the welding heat process, improve laser energy efficiency, reduce welding defects and control weld shape. The scientific numerical simulation with technical experimental verification is implemented to investigate the heat process of LDPW for aluminum alloy in this thesis. the law of temperature field and the influence of welding parameters during the process of LDPW for aluminum alloy under preheating condition are analyzed, which provides the theoretical basis for the basal research on hybrid welding method of laser welding and resistance seam welding.In numerical simulation of LDPW, the selection of heat source model is directly related to the simulation accuracy. This paper summarizes the analytical and numerical solutions of the heat source model of LDPW and analyses its advantage and limitation. Based on the analysis of LDPW theory, a new surface-body combination heat source model is established to simulate the heat transfer process. The combination heat source model uses Gaussian surface heat source model to simulate the heating effect of plasma and surface melting pool and uses rotation Gaussian body heat source model to simulate the heating effect of keyholes. Experimental verification shows that the use of this surface-body combination to simulate the temperature field of LDPW is reasonable.According to describe the heat transfer equation of welding process, based on the finite element method and ANSYS software, three-dimensional finite element model of numerical simulation of LDPW for aluminum alloy lap joints is established. By analyzing the performance change of metal materials at high temperature phase, combined with the middle and low temperature performance parameters, the curve of materials hot physical parameters in the welding temperature range is acquired. The transitional mesh can reduce the model freedom degree and amount effectively. The mesh size of laser beam process region is...
Keywords/Search Tags:aluminum alloy, laser deep penetration welding, heat resource model, finite element, numerical simulation, temperature field
PDF Full Text Request
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