Vibration analysis of medical devices with a calibrated FEA model
This study presents vibration analysis of medical devices by a finite element analysis (FEA) model calibrated with test data. The medical device under investigation is the Lifepak500 automated external defibrillator (AED), a product that is frequently exposed to vibration and shock in transportation means such as ambulances and medical-evacuation helicopters. In structure, the AED is a plastic case that contains a printed circuit board (PCB) with various attached electronic components such as capacitors, resistors, inductors, and integrated circuits. In this study, an FEA model of the AED is established with the use of ANSYS based on design specifications and static tests. The model is first calibrated with various static and dynamic tests to verify that the static displacements at selected locations, PCB twist angles, and first three natural frequencies predicted by the FEA model are consistent with those obtained by the tests. The model is then used to examine the dynamic characteristics and vibration transmissibility of the PCB within both rigid and flexible medical device cases. Finally, random vibration analysis of the PCB is presented. This study shows that the predicted frequency data favorably agrees with test data (within 7% error range), while predicted vibration amplitudes are in a reasonable range at major PCB locations when compared with the test data, but do not always agree well at the locations where the PCB has more complicated structural features and boundary conditions. The established FEA model predicts the reliability and functionality of current design of the AED from a vibration viewpoint. It can also help engineers improve the PCB mechanical design and product reliability when used in harsh vibration environments.
fea model ansys static and dynamic tests printed circuit boards of medical devices vibration and shock responses