3D Modelling of the Scattering of the Fundamental Anti-Symmetric Lamb Mode (A0) Propagating within a Point-Impacted Transverse-Isotropic Composite Plate

Abstract

The present paper deals with an effort to model impact damage in 3D-FE simulation. In this work, we studied the scattering behavior of an incident A0 guided wave mode propagating towards an impacted damaged zone created within a quasi-isotropic composite plate. Besides, barely visible impact damage of the desired energy was created and imaged using ultrasonic bulk waves in order to measure the size of the damage. The 3D-FE frequency domain model is then used to simulate the scattering of an incident guided wave at a frequency below an A1 cut-off with a wavelength comparable to the size of the damaged zone. The damage inside the plate is modeled as a conical-shaped geometry with decayed elastic stiffness properties. The model was first validated by comparing the directivity of the scattered fields for the A0 Lamb mode predicted numerically with the experimental measurements. The modeling of the impact zone with conical-shape geometry showed that the scattering directivity of the displacement field depends significantly on the size (depth and width) of the conical damage created during the point-impact of the composite with potential applications allowing the determination of the geometric characteristics of the impacted areas.

Damage Localization on Composite Structures Based on the Delay-and-Sum Algorithm Using Simulation and Experimental Methods

“…The technical data sheets indicate that the stacking sequence is [45/0/0/45/0/45/0/45/0/45] S , where the axis of symmetry is along the thickness direction. As announced in the introduction, this plate was the subject of a previous study [34] in which the optimized dispersion curves and elastic constants were determined experimentally (Table 1). Data given in Table 1 show that the symmetry is transverse isotropic, which is not in accordance with the given stacking sequence.…”

“…Section 2 presents the damage localization methods based on the delay-and-sum algorithm in the case of anisotropic materials for simulated and experimental results. Section 3 presents the study of a transverse isotropic composite plate taken at the damaged state (impacted state), where impact has been modeled as conical in shape with degraded mechanical properties (details of this work can be found in [34]). Baseline signals are obtained based on 3D numerical simulation results performed using the SHM module of the CIVA software.…”