Research On Basic Mechanical Properties Of Sandwich Panels With Cylinder-shaped Periodic Tubes Involving Band Gaps

Periodic composite structure is a new type functional structure with phononic band-gaps, which stops the vibration in certain frequency regions traveling through this structure. As a special periodic composite structure, periodic sandwich panels, filled with porous and low thermal conductive material, exhibit the characteristics of vibration isolation and heat preservation. It is of significantly importance to optimize the multi-functional sandwich panels by artificial design, so that the structure presents good carrying capacity with wide band gaps involved.First, calculation and analysis of the band gaps for the sandwich panels with cylinder-shaped periodic tubes filled with polystyrene is carried out using Comsol Multiphysics software in this paper. And then, theoretical analysis, numerical calculation by ABAQUS software and the experiments on the mechanical properties of the panels for bending, shearing, flat and side compression are performed respectively. The influences of geometric parameters on the mechanical properties are discussed and the optimal design suggestions are given. Investigation on the panels shows that:1. The sandwich panel with cylinder-shaped periodic tubes has a good vibration isolation performance. The height of the tube and the thickness of the plasterboard individually impact on the centre frequency and the width of the band-gap. The higher the steel tube is, the wider the first band-gap, and the lower the band-gap centre frequency. With increasing of the plasterboard thickness, the width of band-gap becomes smaller, and the center band-gap frequency increases.2. The bending strength of the sandwich panels is controlled by the tensile strength of the plasterboard, while the shear and compression (flat compression and side compression) strengths are controlled by the compressive strength of the plasterboard. The panels exhibit a strong bearing capacity for bending. As the thickness of the plasterboard increases, the bending failure load increases and the ultimate displacement decreases. The foam-filled sandwich panels exhibit greater stiffness and better flexural capacity than that of the panels without foam filled.3. The experimental results of the four-point bending and flat compression are all in coincident with that of the numerical simulation and theoretical calculation. The experimental shearing results agree with that of the theoretical estimates. The experimental and the numerical simulation results for side pressure are in good agreement.4. Higher connection strength can significantly improve the bending and shearing capacity of the sandwich panels. The larger radius and thickness of the tube used, the higher of pressure bearing capacity can reach. Filling with polystyrene in the sandwich panels can increase both the thermal insulation property and structure bending strength without any influences on the band-gaps. It’s better to use the material with small Young’s modulus and higher flexural strength as panels and the thickness should be moderately increased.