FINITE ELEMENT ANALYSIS FOR DYNAMIC RESPONSE OF VISCOELASTIC SANDWICHED STRUCTURES INTEGRATED WITH ALUMINUM SHEETS

Abstract

Passive vibration attenuation of modern mechanical structures is one of the most essential technologies applied to the arsenal of modern mechanical structures. In this work, dynamics analysis is performed on viscoelastic (VE) sandwich beam and plate by using finite element method. The proposed structure is composed of a VE core and aluminum face sheets as substrate layers on both sides of the structure. Small-strain VE material is modeled based on complex constant moduli model and numerical method is used to develop the finite element (FE) shear model based on first-order shear deformation theory (FSDT) and Hamilton principle. In modal analysis, model-effective mass analysis is performed to investigate its dominant mode shape and sweet spot at resonance using C3D20 and CPS8 elements. The former is indicated as a 3-D element with 20 nodes while the latter is indicated as a 2-D plane strain element with eight nodes. In harmonic analysis, resonance frequency is obtained based on mode superposition method to evaluate the steady-state response of VE sandwich beam via maximum deformation. Thereafter, the results are compared against analytical solutions from the literature. Moreover, a parametric study shows that the natural frequency of the beam did not change with the increase in core thickness. However, normalized loss factor of VE sandwich beam  is directly proportional to VE damping factor  and the thickness of VE core layer. Based on frequency response function, the results of resonance frequencies for VE beam are in the range of modal natural frequency.