INVESTIGATION OF VIBRATION BEHAVIOR OF FR4 AND ALUMINUM PCB MATERIALS USING THE MAC METHOD

In this study, plates made of two different materials used in PCB (Printed Circuit Board), FR4 and Aluminum, have been investigated by experimental modal analysis (EMA) and finite element method (FEM) modal analysis. Firstly, dynamic structural characteristics of plates, consisting of modal shapes, damping ratios, natural frequencies have been calculated by the help of ANSYS® R23 software. Afterwards, to determine the vibrational characteristics of the plates by EMA, rowing hammer, roving accelerometer and modal shaker tests have been performed by the help of DEWESOFT® data acquisition hardware and its corresponding software. Frequency response function (FRF) is measured by EMA software and FRF were exported to be analyzed by MEScope® modal analysis software. In MEScope® software, FRF’s between excitation points and measurement points were matched with corresponding points of the structure geometry. Modal assurance criteria (MAC) were calculated between the EMA and FEA modal shapes. Results of impact hammer test method obtained to closer to the results of numerical analysis than other methods. It has also been observed that the dimensions of the variable plates affect the MAC results. Additionally, importance of the gravity and mass balance on the structure were analyzed specially for thin structures, indicated actions to cope with mass balance issue.