电路板工装结构设计及其振动传递特性研究

针对印制电路板环境应力筛选试验要求，为减小夹具对试验结果的影响，提出以电路板尺寸、筛选效率以及固有频率等为约束的电路板工装设计优化方法，并以某型电路板为例进行电路板工装设计与迭代优化；继而开展模态仿真分析验证了工装设计的有效性；研究设计工装振动特性并固化电路板环境应力筛选测试方案，采用设计工装及固化方案完成电路板随机振动环境应力筛选试验。结果表明:所设计工装的一阶固有频率高于试验规定频率上限，满足工装夹具刚度特性要求。通过合理装夹和调整传感器布局等可使得电路板安装位置加速度功率谱密度曲线及均方根值满足GJB 1032A相关要求。

Structure design of the PCB fixture and its vibration characteristics

Based on the environment stress screening (EES) test requirement for the printed circuit board (PCB), an optimization method is proposed for the design of the PCB’s fixture with the constraints of the PCB size, the test efficiency and the natural frequency of the structure, to reduce the influences of the fixture on the test results. A certain type of PCB is taken as an example, and its fixture is designed with the iterative optimization. The effectiveness of the designed fixture is verified by the modal test analysis. The vibration transmission characteristics of the designed fixture are analyzed and the test scheme is then solidified. Based on the fixture and the determined program, the random vibration tests of the EES for the PCB are carried out. It is shown that the first order natural frequency of the designed fixture is higher than the upper limit of the specified test frequency band, thus the fixture meet the stiffness requirement. Through reasonable mounting and arrangement of sensors, the errors of the PSD curves of the acceleration and the root mean square (RMS) values at the control points can meet the relevant requirements of GJB 1032A.