振动时效过程模拟与分析

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Because of a lack of understanding of the mechanisms behind vibratory stress relieving,this process has not been widely used in industries.A finite element model was developed to predict weld residual stress and simulate the process of vibratory stress relief（VSR）.And the effect of VSR process parameters,such as exciting force,frequency and so on,was investigated with the developed model.It was found that whether resonant or nonresonant VSR,only when certain amount of microscopic plastic deformation is produced that the residual stress can be released.The smallest exciting force would be needed at the first-order modal which is the best choice in all.For other frequencies,the stress reduction strongly depends on the exciting force.由于缺乏对振动时效机理的有效解释,通过振动时效消除残余应力的方法一直未得到广泛应用。采用有限元法对焊接件残余应力的产生及振动消除过程进行了数值模拟,分析了激振力和激振频率等振动时效工艺参数对残余应力消除程度的影响。仿真结果表明,无论构件是否达到共振状态,只有产生一定的微观塑性变形残余应力才能得以释放;一阶模态能在最小的激振力下消除残余应力,是振动时效的最佳选择,而在其它频率,应力消除率取决于激振力的大小。