Model-based Evaluation of Electro-mechanical Impedance Measurements for Detection and Size Identification of Face Layer Debondings in Sandwich Panels

Abstract

The present work investigates, based on simple beam models, the well-established vibration based electro-mechanical impedance method as a potential Structural Health Monitoring (SHM) method for the monitoring of debonding in sandwich structures. The Finite Element Method (FEM) is used to analyze the response of a simple beam on different linear and non-linear elastic foundations, representing a sandwich face layer debonding, to a harmonic excitation. First, a finite element based approach to study nonlinear steady-state vibrations of structures is developed and discussed by analytical considerations. Consecutively, the numerically calculated structural responses are presented in detail and their non-linear features are revealed. Finally, the model based findings are discussed regarding their potential to help monitoring damages like, e.g., sandwich face layer debonding that provoke a non-linear response to a harmonic excitation and a short outlook of related future research is given.