随机振动载荷下电子箱PCBA焊点疲劳寿命分析

Fatigue Life Analysis of PCBA Solder Joints in Electronic Box Under Random Vibration Load

电子箱在力学载荷环境下,振动引起的高周循环疲劳应力会造成箱体中电路焊点失效,影响电子箱整机可靠性;针对一种印制电路板组件焊点进行整机级振动试验,通过建立电子箱整机有限元模型,进行与试验状态一致的随机振动试验仿真分析,提取焊点上的应力、加速度响应水平;基于Basquin模型,建立了PCBA疲劳寿命预测模型,将几种不同振动载荷下的焊点响应结果代入到预测模型,计算得到电子箱在不同振动载荷下的寿命分析结果,得到电子箱PCBA焊点的应力-寿命(S-N)曲线;结果表明,在工况随机振动条件下电子箱PCBA焊点具有足够可靠性,随着振动激励增大,焊点疲劳寿命显著缩短,该方法可用于电子箱整机级PCBA焊点随机振动疲劳寿命分析。

Under the mechanical load environment of electronic box,the high cycle fatigue stress caused by vibration will cause the failure of the circuit solder joints in the box,which will affect the reliability of the electronic box.The whole machine vibration test was carried out for a kind of printed circuit board(PCB) solder joint. By establishing the finite element model of electronic box,the random vibration test simulation analysis was carried out consistent with the test state,and the stress and acceleration response levels of the solder joint were extracted. Based on the Basquin model,the fatigue life prediction model of PCBA was established. By substituting the response results of solder joints under different vibration loads into the prediction model,the life analysis results of electronic box under different vibration loads were calculated,and the stress-life(S-N) curve of electronic box PCBA solder joints was obtained. The results show that the PCBA solder joint of electronic box has sufficient reliability under the condition of random vibration,and the fatigue life of the solder joint is significantly shortened with the increase of vibration excitation. This method can be used to analyze the random vibration fatigue life of PCBA solder joint of electronic box.