电阻法用于扩散焊接头微孔缺陷评价的数值模拟

Numerical simulation on microdefect evaluation of diffusion bonded joints by resistance approach

从扩散焊接头界面微孔实际形貌和分布特征出发，提出了界面微孔周期性分布的二维有限元模型，应用ANSYS电磁场分析模块，考察了界面焊合率、界面微孔宽度和长度对电阻增量的影响。结果表明，扩散连接接头的界面焊合率与电阻增量之间呈双曲线变化规律，界面微孔的宽度和长度对电阻增量均有影响。当界面焊合率在20％～80％范围内时，电阻增量与界面焊合率之间表现出更高的敏感性。基于Lodge等人提出的扩散焊界面焊合率与电阻增量关系式，建立了能够包含界面微孔几何尺寸影响的修正方法。

In terms of the morphology and characterization of interfacial microdefect of diffusion bonded joints,a two-dimension finite element model with the periodically distributed microdefects on the interface was presented.The influences of interfacial contact ratio,width and length of microdefects on increments of resistance were analyzed by applying the electromagnetic module in ANSYS software.Results indicated that there is a hyperbolic variation between the interfacial contact ratio and increment of resistance of diffusion bonded joints.The increment of resistance is affected by both width and length of interfacial microdefects.A higher sensitivity between the increment of resistance and interfacial microdefects was observed when the interfacial contact ratio was in 20%-80%.Based on the theoretical expression of contact ratio and increment of resistance proposed by Lodge et al,a modified equation was developed to accommodate the effects of size of interfacial microdefect,which can lead to a more precise evaluation for integrity of diffusion bonded joints.