Failure Modes of Flexible Electronics Under Mechanical Vibration

摘要

The use of flexible electronic components has increased considerably, and a study on the different vibration profiles for different fixtures and loads are of great importance in determining the conditions required to evaluate the reliability of flexible boards. Hence, in this study the behavior of flexible electronic circuit boards under different acceleration levels of vibration and with different fixtures are investigated. The vibration amplitudes of the flexible board at different locations are calculated from the strain gauge measurements from those respective locations. Further the change in the strain measurements at a location of the board is compared for different acceleration levels of vibration and for different type of fixture used during vibration. To study the change in behavior of the flexible board during the up-sweep and down-sweep vibration profiles, strain measurements at each location for up-sweep and down-sweep profiles were analyzed based on frequency and statistical characteristics of the signal. The variation of maximum amplitude at a location during the upsweep and down sweep vibration profile of the shaker frequency is also studied for all conditions of acceleration levels and for different fixtures. A comparative study on the flexible board vibration signals and a rigid board at the same vibration levels and location were also carried out to find the similarities and differences in the behavior of both. Frequency and time-frequency information of the strain signals were also analyzed and change in the occurrence of frequency components for upsweep and down sweep vibration profiles were studied for different fixtures and acceleration loads. A detailed analysis on the failure of flexible circuits for different fixtures and for different acceleration levels were also conducted to determine the optimum fixture for vibration at various vibration levels. This will also help in designing different types of fixtures for different levels of vibration and for minimizing the maximum amplitude vibrations for each fixture.