| Lightweight materials such as aluminum alloys,magnesium alloys,and titanium alloys are widely used in automobiles,aerospace,aerospace,warships,and weapons and equipment because of their low density and high strength.Lightweight materials and their components have become an effective way to reduce the weight of major equipment.Metal thermoforming is a high-efficiency,high-quality,low-loss plastic processing technology and is also the development direction of international advanced high-performance lightweight material component advanced manufacturing technology.However,lightweight materials such as aluminum alloys,magnesium alloys,and titanium alloys have high thermal conductivity,and the cooling rate during the thermal forming process is too high.Due to the temperature-sensitive and narrow forming temperature window,the excessively fast cooling rate leads to defects such as large deformation resistance and easy cracking in the above-mentioned light-weight material member during the hot forming process,which seriously restricts the development and application of the thermoforming technology of light-weight material members.The electromagnetic induction assisted heating forming technology can realize online heating of components,thereby solving the technical problem of rapid temperature drop during the thermal forming process of lightweight material components.However,electromagnetic induction-assisted heating is a complex process in which multiple couplings of electricity,magnetism,heat,and force,as well as electromagnetic parameters,thermal parameters,forming parameters,etc.,interact with each other.How to realize the multi-field coupling of electric,magnetic,thermal,and force numerical simulation is a key technical problem that electromagnetic induction auxiliary heating forming technology urgently needs to solve.The specific research content is as follows:(1)A bidirectional real-time mathematical model of coupling multi-physics of electro-magnetic-thermo-plastic deformation is established,and a multi-field bidirectional real-time coupling calculation method of electro-magnetic-thermo-plastic deformation is proposed.Based on the above mathematical model,based on the ANSYS/Multiphysics module and ANSYS/LS-DYNA module,combined with ANSYS APDL language,a finite element simulation model of electromagnetic induction assisted heating was established.And the key knot modeling problems of discretized loading of electromagnetic induction temperature field,loading of plastic deformation temperature field,determining the unit type and reconstructing of blank nodes in multi-field coupling calculation.This finite element simulation model eventually realized the bi-directional real-time coupling simulation of electromagnetic induction temperature field and plastic deformation thermal field.(2)A finite element simulation model of the aluminum alloy electromagnetic induction assisted heating upsetting forming was established,and the bidirectional realtime coupling simulation calculation between the aluminum alloy electromagnetic induction temperature field and the thermal field of upsetting forming process was realized.The evolution of blank temperature distribution in aluminum alloy electromagnetic induction assisted heating upsetting forming process was revealed,and the influence of current intensity on temperature distribution of the blank in aluminum alloy electromagnetic induction assisted heating upsetting forming process was clarified.(3)A finite element simulation model of aluminum alloy electromagnetic induction assisted heating ring rolling process was established,and the bidirectional real-time coupling simulation calculation between aluminum alloy electromagnetic induction temperature field and ring rolling forming thermal field was realized.The evolution law of the blank temperature distribution during the process of aluminum alloy electromagnetic induction assisted heating ring rolling was revealed,and the influence law of the current intensity on temperature distribution of the blank during the process of the aluminum alloy electromagnetic induction auxiliary heating ring rolling was clarified.In this Thesis,it is of academic value and practical significance to develop a multifield coupled numerical simulation theory for electric,magnetic,thermal,and force,and to develop an electromagnetic induction assisted thermoforming technology method to promote the development and application of electromagnetic induction assisted thermoforming technology. |
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