Abstract
Micro-speaker diaphragms play an important role in generating desired sound responses, and are designed to have thin membrane shapes for flexibility in the axial direction. The micro-speaker diaphragms are formed from thin polymer film through the thermoforming process, in which local thickness reductions occur due to strain localization. This thickness reduction results in a change in vibration characteristics of the diaphragm and different sound responses from that of the original design. In this study, the effect of this thickness change in the diaphragm on its vibration characteristics is numerically investigated by coupling thermoforming simulation, structural analysis and modal analysis. Thus, the thickness change in the diaphragm is calculated from the thermoforming simulation, and reflected in the further structural and modal analyses in order to estimate the relevant stiffness and vibration modes. Comparing these simulation results with those from a diaphragm with the uniform thickness, it is found that a local thickness reduction results in the stiffness reduction and the relevant change in the natural frequencies and the corresponding vibration modes.
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Kyung-Min Kim received her B.S. degrees in School of Mechanical Design and Automation Engineering from Seoul National University of Science Technology, Korea in 2011. She then received her M.S. degree in Graduate School of NID Fusion Technology from Seoul National University of Science Technology, Korea in 2013. Ms. Kim is currently a CAE engineer at Space Solutions Co. Ltd., Korea. Her research interests include finite element analysis of various engineering problems.
Keun Park received his B.S. and M.S. degrees in Precision Engineering and Mechatronics from KAIST, Korea, in 1992 and 1994, respectively. He then received his Ph.D. degree in Mechanical Engineering from KAIST in 1999. Dr. Park is currently an Associate Professor at the Department of Mechanical System Design Engineering at Seoul National University of Science and Technology, Korea. His research interests include numerical analysis of material forming processes and microfabrication of plastic parts.
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Kim, KM., Park, K. Numerical investigation on vibration characteristics of a micro-speaker diaphragm considering thermoforming effects. J Mech Sci Technol 27, 2923–2928 (2013). https://doi.org/10.1007/s12206-013-0804-5
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DOI: https://doi.org/10.1007/s12206-013-0804-5