Experimental and semi-analytical investigation of dynamic behavior of sandwich plates with porous core and CFRP face sheets

Abstract

This paper presents an experimental and theoretical investigation of the vibration behavior of sandwich plates consisting of an Expanded Polystyrene (EPS) porous concrete core and carbon fiber-reinforced polymer (CFRP) face sheets. For the theoretical study, Reddy’s third-order shear deformation theory (RTSDT), combined with the pb-2 Ritz method, is employed to formulate the governing equations, from which natural frequencies are obtained via eigenvalue analysis and dynamic responses are computed using the Newmark integration scheme. The numerical model is validated against established benchmarks. For the experimental study, rectangular sandwich plate specimens with CFRP layups are fabricated and tested under two opposite edges simply supported and the remaining two edges free (SFSF) boundary conditions. The fundamental natural frequencies are measured using step-release free vibration tests with five accelerometers and Fast Fourier Transform (FFT) analysis. The experimentally obtained natural frequencies are then compared with the semi-analytical predictions. The close correlation between the two approaches confirms the reliability of both the proposed model and the experimental procedure. The outcomes of this study can be valuable for the design and analysis of lightweight sandwich plates with porous cores and composite face sheets.