Effects of random damages on dynamic behavior of metallic sandwich panel with truss core

Abstract

Random damages in the core or face/core interface often appears during fabrication or application of metallic sandwich panels with truss core, and may significantly affect the dynamic behavior of the sandwich panel. Two types of evaluation parameters, i.e., global parameters and local parameters, are used to evaluate the effect of random damages. A finite element model in conjunction with stochastic number program that can automatically specify random damages of various extents is developed. Experiments were conducted to verify the proposed analytic model and technique. Three factors affecting dynamic properties of the damaged sandwich are considered, including damage extent, boundary condition and damage zone. Results show that variations of structural dynamic property are in proportional to the damage extent and the concentration degree of random damages, and increases as the constraint of boundary condition is enhanced. Effects of random damages on both natural frequencies and mode shapes are usually in accordance. Damages in the zone covering structural local vibration modes or maximal vibration amplitude would have greater influences on natural frequencies and mode shapes than damages in other zones. (C) 2016 Elsevier Ltd. All rights reserved.