Nonlinear Analysis of Flexible Supports for Flat Loudspeakers

• Main Authors: Tsai, Pin-Ta, 蔡秉達
• Other Authors: Kam, Tai-Yan
• Format: Others
• Language: zh-TW
• Published: 2009
• Online Access: http://ndltd.ncl.edu.tw/handle/75613316898802490784

碩士 === 國立交通大學 === 機械工程系所 === 98 === Due to the physical and electrical characteristics of flexible supports and voice coil, the Sound Pressure Level (SPL) may behave nonlinearly with the increase of voltage rather than varying linearly. In general, owing to geometric nonlinearity, the rigidity of a flexible support may experience hardening or softening when subjecting large deformation. In this thesis, we discuss several designs of flexible supports including elastic damper (2D or 3D) and suspension. The purpose is to enlarge the range for linear deformation while at the same time maintain the symmetry for positive and negative directions of deformation when designing the elastic dampers and suspension. The goal can be achieved by adjusting the shape and dimension of the flexible supports. First, we find the load-displacement curve of a flexible support via the static experiment, and then we use ANSYS to construct a finite element model of the speaker. Based on the nonlinear deformation and linear harmonic exciting analyses, the SPL curve is obtained and used to verify the results of static and SPL tests so that we can identify the material properties of the supports and find out the linear displacement ranges of the supports. Finally, we use two optimal support combinations including 2-D or 3-D elastic supports and suspension to study the SPL curves of the speaker theoretically and experimentally. The results show that the choices of the optimal flexible supports can produce larger linear range for the SPL curves.