提出了利用数字图像相关技术测量印刷电路板全场微应变的方法, 用于评估电路板由应力所导致的失效风险, 克服传统实验测试方法不能有效测量全场应变以及难以给出应变集中区域的不足。设计了基于三维数字图像相关技术和应力加载策略的实验方法, 通过所获得的全场主应变分布及局部区域内应变历史曲线来评估电路板的失效风险。实验结果表明, 所提出的电路板微应变测量方法的重复性优于100 με, 能够有效地获得电路板全场的微应变分布, 尤其是能够直观地显示电路板应变超过额定值的区域分布, 为改进电路板设计、降低电路板失效风险和保护电子元器件的安全提供了重要的实测数据。

A method of full-field micro strain measurement using digital image correlation was proposed to evaluate the risk of printed circuit board assembly failure induced by stress. It outperformed traditional testing methods based on experiment in terms of full-field strain measurement and location of strain concentration. Experimental method based on three-dimensional digital image correlation and stress loading strategy was designed. The risk of circuit board assembly failure was evaluated by the obtained full-field distributions of principle strain and history curves of strain on selected local areas. High repeatability of the presented method, which was better than 100 με, was exhibited by the experiments, allowing the obtainment of the circuit board assembly full-field micro strain distribution. Moreover, areas where strain exceeds rated value can be localized easily and exhibited intuitively. The presented method provides important measured data which can be used to improve the circuit board assembly design, reduce the risk of circuit board assembly failure, and protect the safety of electronic components.