Estimation of strains in composite honeycomb sandwich panels subjected to low frequency diffused acoustic field

摘要

Acceleration responses of panels subjected to diffused acoustic field are often determined using a coupled Finite Element - Boundary Element Method. In many such models the structure is represented by its natural modes and the acceleration responses can be determined. But for the verification of the structure for its survivability, its strain responses are essential to be determined. In practice such coupled models do not have the information on the structural details and hence it is not possible to determine the strains in the structure. A methodology to estimate the strains in the low frequency modes of the structure based on the acceleration responses is developed in this work. An expression relating the spectral density of strain to the spectral density of the acceleration is derived. A composite honeycomb sandwich panel is subjected to diffuse acoustic field in a reverberation chamber and accelerations, strains are measured. The strains are estimated using the methodology developed in this work and it is seen that the strains determined using this technique are very much in agreement with the measured strains. Thus, the present work enables determination of strains in the panel even when the structure is represented by its free vibration characteristics and its physical properties are not known. (C) 2019 Elsevier Ltd. All rights reserved.