Vibration behavior of metallic sandwich panels with Hourglass truss cores

Exploring lightweight sandwich structures with excellent load-bearing and vibration damping performances is one of the important topics in structural and functional applications. The aim of the present work is to design, fabricate novel metallic sandwich structures with Hourglass truss cores and investigate their modal characteristics and vibration isolation performances by comparing with the traditional pyramidal sandwich structure experimentally and numerically. It is shown that the natural frequencies of the Hourglass sandwich structures are much higher than that of the pyramidal sandwich structures under free-free boundary condition and equal relative density of the truss cores. The torsional modes and transverse bending modes of the Hourglass sandwich structures separately play a dominant role in lower and higher modes of vibration, which are opposite to the pyramidal sandwich structures. From the results of the acceleration frequency responses and vibration level difference (VLD), it is indicated that the Hourglass sandwich structures exhibit better vibration isolation performance than the pyramidal sandwich structures. Furthermore, experimentally validated finite element analysis (FEA) models are developed to study the influences of truss inclination angles and boundary conditions on the modal characteristics of the present sandwich structures. Some conclusions are summarized, which may be useful for understanding the vibration behavior of such kinds of lattice sandwich structures.