Chip-barrier/printed-wiring-board joints have been tested isothermally, at 35 degrees C, in shear. The joints were subjected to fully reversed cycling with fixed plastic displacement limit. The fatigue life was correlated with this displacement by a pseudo Coffin-Manson law. The fatigue life was defined in terms of 25%, 50%, 90%, and 100% drop in the load required to produce a given displacement. The resistance of each of 22 joints was also measured and the fatigue life, N/sub f/, defined in terms of the first joint to increase by 0.02%, 0.05%, 0.1%, 1%, 10%, 100%, and 10*. The results were found to be in general agreement with those obtained previously on single, larger, solder joints. Some variations were noted in the Coffin-Manson exponent, depending on how the displacement and fatigue lives were defined. This is discussed along with a model describing the process of joint failure. A set of displacement versus fatigue life curves which can be used to estimate the joint life on the basis of a variety of criteria is provided.
展开▼
机译：切屑阻隔层/印刷线路板接缝已在35摄氏度的等温下进行了剪切试验。在固定的塑料位移极限下，对接头进行完全反向的循环。疲劳寿命通过伪科芬曼森定律与该位移相关。疲劳寿命定义为产生给定位移所需的载荷下降25％，50％，90％和100％。还测量了22个关节中每个关节的阻力，疲劳寿命N / sub f /（根据第一个关节定义）分别增加了0.02％，0.05％，0.1％，1％，10％，100％和10 *。发现结果与先前在单个较大的焊点上获得的结果基本一致。 Coffin-Manson指数中指出了一些变化，具体取决于位移和疲劳寿命的定义。与描述关节破坏过程的模型一起讨论了这一点。提供了一组位移与疲劳寿命曲线，可用于根据各种标准估算接头寿命。
展开▼
