Optimal Design of Corrugated Cellular Plastic Foam with Semi-elliptical Shaped Upper Surface by Finite Element Frequency Domain Acoustic Analysis

Abstract

A general way to enhance the sound absorption capability of cellular plastic foam is the use of corrugated foam. The corrugated surface can greatly enhance the sound absorption of the foam in the mid and high frequency ranges. In this study, a finite element frequency domain acoustic analysis is used for the analysis. Such a numerical method is more efficient than the methods used in earlier studies as it saves the calculation time on the elements of the incident acoustic field. During the optimal design of the corrugated cellular plastic foam with semi-elliptical shaped upper surface, the cross-sectional width (the length of the minor axis) and the area of one section of the corrugated foam are kept the same throughout the study. The variation of the semi-elliptical shape is performed by changing the length of the semi-major axis. By varying the length of the semi-major axis, the maximum sound absorption capability of the semi-elliptical shaped corrugated foam is found. It is concluded that in the high frequency region (2000—4000 Hz), the foam with the major axis to the cross-sectional width ratio (MWR) of 1.96 has the maximum sound absorption capability and its broadband averaged normal incidence sound absorption coefficient is improved from 0.882 to 0.945.