中厚度铝合金板变极性等离子弧焊热源模型的建立

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Abstract：Thisstudyis groundedinthetheoretical frameworksofheat transferandthermo-elastic-plastic finite element analysisandcombined withwelding theory tosystematicallyinvestigatethegoverning equationsandboundaryconditionsof thetemperature fieldin variablepolarityplasma arc welding（VPPAW）of aluminumallys.Bycomparing thedistinctcharacteristics of positiveandnegativepolaritycurrentsandtheelectronemision modesofdifferent electrodes，teheatgenerationmechanismofVPPAWforaluminum allysisanalyzed.Finaly，considering the workpieces’thicknessandtheunique features of VPPAW，a double-elipsoidal heat source model is selected.Specific parameters forthe heat source modelof 8mm-thick aluminum ally plate VPPAWare established.Secondary development of the double-ellpsoidal heat source model is implemented using FORTRAN toachieve cyclic loading of alternating positiveand negative polarityheatsources. Thetemperatureand stressfields during welding are simulated using the SYSWELD finite element analysis software.

Keywords：aluminum alloy;VPPAW;heatsourcemodel

铝合金具有比重小、比强高、优良的低温性和可加工性、抗腐蚀性能等优点，已经广泛应用在航空、航天、车辆、船舶、土木工程等各个领域-3]，但是，由于铝合金易氧化、热导率高、线膨胀系数大等特点，给其焊接带来许多问题，科研人员不断提出和完善铝合金的焊接方法及工艺。（剩余4252字）