Influence of aperture shape on dynamic behaviors of sandwich plates by means of improved isogeometric analysis and experimental tests

Due to assembly and lightweight design, various apertures are involved in composite and sandwich plates, which will influence the natural frequencies and vibration modes of these structures. If the influence mechanism of aperture shapes on dynamic characteristics of composite and sandwich plates is not clarified, structural safety will be significantly impacted as external loads are close to the natural frequencies of composite plates with apertures. Nevertheless, experimental tests in conjunction with accurate analysis on the dynamic response of composite and sandwich plates with different aperture shapes are less reported in published literature, so the influence mechanism of aperture shapes on dynamic characteristics of composite and sandwich plates is required to be clarified precisely. Thus, a novel refined sinusoidal higher-order theory (RSHT) combined with iso-geometric analysis (IGA) is proposed, where the improved bending strip method (IBSM) has been reconstructed to satisfy approximately the C-1-continuity in multi-patch IGA. Four sets of tests on free vibration of rectangular sandwich plates with different sizes of circular cutouts are carried out to verify the reliability of the proposed method. Numerical results and experimental tests show that the proposed RSHT can predict more accurately the influence of aperture shapes on dynamic behaviors of sandwich plates, and the influence mechanism of aperture shapes on dynamic characteristics of sandwich plates has been illustrated, which can provide a reference for other investigators.