In today’s automotive industry sound package material design and optimization is important considering the need for weight reduction and achieving targeted sound absorption and sound transmission loss values. As per traditional approach vehicle level noise reduction targets are defined considering flat samples, but in actual vehicle condition molded trimmed parts are used.
This paper discusses about the systematic methodology developed for molded sample characterization in terms of BIOT’s properties. Effects of different parameters like area wise thickness variation, density variation on BIOT properties is studied. Comparison of BIOT’s properties of flat and molded dash sample is done to study the effect of molded structure.
Using these BIOT’s properties prediction of sound absorption and sound transmission loss results carried out using FTMM approach for flat sample and SEA approach for molded sample. These predicted results validated with experimental sound absorption and sound transmission loss measured in reverberation chambers and in impedance tube.
Finally, suggestions are given to account critical parameter like thickness variation affecting the BIOT’s properties and in turn acoustic performance of sound package material. It can help NVH engineers during actual design and development of sound package material.