Abstract
A numerical method is proposed to calculate response analysis for automotive sound proof structure including elastic body, viscoelastic body and porous body using three dimensional FEM and MSKE method. Displacement vectors as common unknown variable under coupled condition. The explicit expressions of modal loss factors for the sound proof structures are derived using Modal Strain and Kinetic Energy Method (MSKE method) proposed by authors in our previous paper. Using this technique, eigenvalue analysis and frequency response analysis are performed for the automotive sound proof structure. In this report, we deal with a porous material sandwiched between a steel cover plate and a base plate (steel plate with a viscoelastic damping layer). We investigate vibration transmission characteristics from the base plate to the cover plate. Especially, we focus on the influences of curvature of the base plate on the vibration transmission. We set the curved plate as a convex upward structure, while the cover plate is leveled. Thus, the distance between the base plate and the cover plate become short locally because of the curvature. This caused sound bridge phenomena.
