Guided Elastic Waves in CFRP Plates with Random Material Properties

Abstract

Structural health monitoring (SHM) of modern composite materials, e.g. carbon fiber reinforced plastics (CFRP), is a challenging task. Their complex microstructure has a strong influence on the propagation of ultrasonic guided waves. The classical deterministic finite element (FEM) does not take this fact into account. In the current work, an approach for the simulation of waves in structures with random material properties is presented. An important element in the analysis of uncertain systems is the representation of the stochastic properties in such a manner that they can be implemented in a finite element formulation of the given problem. This is then called stochastic finite elmenent method (SFEM) and can be seen as an extension of the classical FEM. The application of the SFEM to two-dimensional (2D) elastic wave propagation problem is presented. The Youngs modulus is modeled as a 2D random field in two ways. In the first case it is constructed with the Karhunen-Loeve Expansion (KLE) and in the second case, with the integration point method.