A Computational and Experimental Study of the Effect of Vibroacoustic Loads on the Structural Performance of Composite Skin-Stringer Joint

The article investigates the response of composite skin-stringer joint to broadband acoustic loading. To describe the frequency and spatial structure of the acting sound field, the study used a model of a field completely correlated over the surface of a sample with a uniform frequency spectral density. The finite element method (FEM) was used to simulate the response of the joint in the 50–1550 Hz frequency band at different total sound pressure levels. To validate the FEM, a series of experiments on a vibration table were carried out, in which vibration simulated acoustic loading. The data obtained were used as the input data for integrating the equations of motion. The results of calculating of the RMS strains in the zone of maximum stresses showed good convergence with the experimental results. For samples containing simulated defects, the resonance frequencies and dynamic response parameters were calculated. Comparison of these results with experimental data characterizing the change in the resonance frequency as a function of defect size made it possible to specify the applied failure criterion and adapt the FEM for analyzing the durability of the composite joint.