一种PCB动态应变的监测方法研究

Research on Monitoring Method of Printed Circuit Board Dynamic Strain

在线监测机电设备印刷电路板在振动载荷作用下的振幅、应变,可实现对PCB分层、焊点断裂、焊点脱落等失效的预测,是保障设备正常运行的关键技术基础之一。基于PCB振动速度与动态应变的数学关系,提出了一种PCB动态应变计算与监测方法。根据Timoshenko薄板应变计算模型,推导出基于振动速度的固支PCB受振动载荷作用时的振幅、应变计算公式;通过实验测得PCB的振动速度和动态应变;利用监测的振动速度数据和推导出的应变计算公式,计算出动态应变并与应变实测结果进行对比分析,结果验证了利用该方法的有效性,为实现PCB分层、焊点断裂、焊点脱落等失效预测提供了技术支撑。

On-line monitoring amplitude and strain of mechanical and electrical equipment printed circuit board under vibration load can realize monitoring of PCB layering,solder joint rupture,solder joint shedding and other failure prediction,which is the key technology to ensure the normal operation of equipment.In this paper,a method of monitoring PCB dynamic strain is proposed based on the mathematical relationship between PCB vibration velocity and dynamic strain.Firstly,according to the Timoshenko general plate strain calculation modal,the amplitude,stress and strain calculation formulas of the supported PCB based on the vibration velocity are deduced;Secondly,the vibration velocity and dynamic strain of PCB are measured by experiment;Then,the dynamic strain is calculated by using the monitored vibration velocity data and the deduced strain calculation formulas.Through the comparison and analysis of the theoretical calculation results and the strain measured results,the effectiveness of the method proposed in the paper is proved,which could provide a technical support for the identification of PCB fault,solder joint fracture,solder joint failure and other failure prediction.