Nonlinear dynamic modeling and experimental study of full-composite cylindrical shells with a foam-filled cavity lattice core

Abstract

Abstract A new full-composite cylindrical shell (FCCS) with a foam-filled cavity lattice core (FFCLC) is developed and prepared, and a nonlinear dynamic model considering the amplitude-dependent property of composite materials is proposed. Compared to traditional linear dynamic models, the lower frequencies and higher resonant responses of structures subjected to base harmonic excitations can be obtained in the proposed nonlinear dynamic model. The nonlinear dynamic behaviors of FFCLC-FCCSs are investigated theoretically and experimentally, in which the fabrication and assembly procedures of FFCLC-FCCS specimens are first provided, and vibration measurements are performed on those specimens subjected to different excitation amplitudes, wherein the soft nonlinear vibration phenomenon characterized by the amplitude-dependent property is discovered. Subsequently, in the framework of the first-order shear deformation theory based on the layerwise principle, the mode superposition approach and the Rayleigh-Ritz method are utilized to obtain the nonlinear frequencies, mode shapes, and resonant responses of the structure subjected to different excitation amplitudes. Therein, the equivalent material parameters of the core part are determined using the modified cross and fill equivalent principle, and the nonlinear elastic modulus with amplitude-dependent fitting coefficients of the skins and core are assumed by the Jones-Nelson nonlinear theory, and those coefficients are determined by using an inverse parameter identification and fitting technique based on experimental test data. Then, the validation work on the developed model is performed by comparing the calculated results of the model with those of the tests. Finally, the impacts of several critical parameters on the nonlinear dynamic behaviors of the structure are estimated, with some suggestions in favor of reducing the nonlinear resonant responses of FFCLC-FCCSs being clarified.