Numerical Analysis of the Main Wave Propagation Characteristics in a Steel-CFRP Laminate Including Model Order Reduction

Abstract

Guided ultrasonic waves are suitable for use in the context of structural health monitoring of thin-walled, plate-like structures. Hence, observing the wave propagation in the plates can provide an indication of whether damage has occurred in the structure. In this work, the wave propagation in fiber metal laminate consisting of thin steel foils and layers of carbon fiber-reinforced polymer is studied, focusing on the main propagation characteristics like dispersion diagrams and displacement fields. For this purpose, the dispersion diagrams derived from the analytical framework and numerical simulations are first determined and compared to each other. Next, the displacement fields are computed using the global matrix method for two excitation frequencies. The results derived from the analytical framework is used to validate the numerically determined displacement fields based on a 2D and a 3D modeling approach. For both investigations the results of the analytical treatment and the numerical simulation show good agreement. Furthermore, the displacement field reveals the typical and well-known characteristics of the propagation of guided waves in thin-walled structures. Since the use of full 3D models involves a very high computational cost, this work also successfully investigates the possibility for model order reduction to decrease the computational time and costs of the simulation without the loss of accuracy.

Investigations on Guided Ultrasonic Wave Dispersion Behavior in Fiber Metal Laminates Using Finite Element Eigenvalue Analysis

“…4 indicate that the propagation of the waves take place over the entire thickness of the specimen. This conclusion is also supported by the numerically computed displacement fields of the fundamental wave modes in [20].…”

“…Muc et al [19] indicate for FML consisting of aluminum and carbon fiber-reinforced polymers (CFRP) and GFRP, respectively, that the results for the occurring group velocities of the stiffness matrix method in combination with finite element models (FEM) are in agreement with those obtained from experimental investigations. Mikhaylenko et al [20] demonstrate that the results for the displacement fields for such waves agree between the results based on the numerical solution of the analytical framework and those from FEM simulations. In addition, the work of Maghsoodi et al [21] and Tai et al [22] address the influence of damage in such material systems.…”

“…This is done by comparing the phase velocity-frequency relations. Based on the results in [20,25] on the dispersion behavior and the displacement fields of the two modes considered here, these modes are referred to as the fundamental symmetric mode S 0 and fundamental antisymmetric mode A 0 . For the computation of the data from the analytical framework, it is refered to [25].…”

A two‐dimensional analysis of the influence of delamination on the wave propagation in a fiber metal laminate

“…FML consist of a stacking of two types of layers of metal (isotropic material) and FRP (anisotropic material). This material system combines the advantages of high strength-to-weight ratio and corrosion resistance of composites with high ductility of metal [3,4]. The specific properties of such combined material are advantageous for lightweight applications.…”

“…This difference in impedance leads to frequency dependent peculiarities in the displacement fields in thickness direction. Detailed studies on this were made in [3]. On the other hand, these investigations show that even in the case of FML the displacement fields cover the whole thickness of the component without phase shift between the top and bottom surfaces.…”