两级低-高加载下拉剪点焊试样的疲劳损伤研究
Fatigue damage Analysis of tension-shear spot welds under low-high loading
徐晓东,王瑞杰,刘学锋,张永亮
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作者单位：昆明理工大学机电工程学院
中文关键字：两级加载；低-高加载；点焊；疲劳损伤；疲劳寿命
英文关键字： two level loading; low-high loading; spot weld; fatigue damage; fatigue life
中文摘要：对拉剪点焊试样进行了两组不同载荷水平的两级低-高循环加载试验，得到随第一级载荷下循环数变化，点焊试样的剩余寿命和总疲劳寿命变化规律。使用Miner线性累积损伤理论计算得到两种不同载荷水平下试样总的疲劳损伤。结果表明：对于低-高加载，随着低载水平下循环数的增多，高载荷水平下的剩余寿命以及损伤值呈逐渐减小趋势，总疲劳寿命逐渐增大。当低载水平载荷幅值较小时，点焊试样破坏时的累计损伤值普遍存在小于1的现象，且这种现象可能对疲劳寿命估算存在一定的影响。
英文摘要：Low-high loading of two different loading levels was applied to tension shear spot welds. The variation of residual life and total fatigue life under the first-level loading cycle number was obtained. Miner linear cumulative damage theory was used to calculate the total fatigue damage under two different load levels. The results show that: for low-high loading, as the cycles under low loading increased, the residual life and the value of damage under high loading are gradually decreased, and the total fatigue life increased. When load amplitude of low loading is low, the cumulative damage values of destructed spot-welded specimens are generally less than 1,and this phenomenon may have impact on the estimating of the Fatigue life.