Dynamic response of doubly curved honeycomb sandwich panels to random acoustic excitation. Part 1: Experimental study

A set of four doubly curved, composite honeycomb sandwich panels has been tested with broad band, random acoustic excitation in a progressive wave tube facility. This paper presents the experimental results in the form of dynamic face plate strain measurements taken from various points close to the centre of the panels, on both the inner and outer face plates. The panels were tested at overall sound pressure levels up to 164 dB (ref. 2×10−5 Pa, over a frequency bandwidth of 60–600 Hz). The response was found to be linear, with a maximum measured root mean square strain of 250με. The doubly curved geometry was found to have a profound effect on the ratio of inner-to-outer face plate strain, which was compared with ratios reported for flat and singly curved geometries. The second part of this study concentrates on three methods for predicting the response of the doubly curved panels to random acoustic excitation.