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Nondestructive Evaluation (NDE) of Materials and Structures from Production to Retirement
Published in Yoseph Bar-Cohen, Advances in Manufacturing and Processing of Materials and Structures, 2018
Lamb waves in plate-like structures can propagate and monitor considerable distances without requiring scanning of the structure on a point by point basis. The Lamb wave propagates through the entire thickness of the structure, which means that it can detect both surface defects and internal defects. Low energy consumption and low cost are advantageous features for Lamb wave–based damage detection approaches (Li et al., 2012a; Pruell et al. 2007). However, the effect of second harmonic generation is weak due to the dispersive nature of Lamb waves, and the multimodal feature of Lamb wave propagation makes it difficult to generate isolated single pure modes experimentally. Thus, the key concept of a nonlinear Lamb wave test is to use those modes with a good “phase matching” associated with significant energy transmission from the fundamental frequency wave mode to the second harmonic wave mode (de Lima and Hamilton, 2003; Deng, 1999). The phase matching condition becomes significant in nonlinear Lamb wave NDE for cumulative effects of the second harmonics while a nonlinear bulk wave technique does not require such precise data calibration (Li and Cho, 2014; Srivastave, 2009). For this purpose, a new definition for a Lamb wave nonlinear parameter is derived with a modification from the conventional bulk wave definition.
Lamb wave propagation in a single lap adhesive joint
Published in Wojciech Pietraszkiewicz, Wojciech Witkowski, Shell Structures: Theory and Applications Volume 4, 2017
M. Rucka, J. Lachowicz, E. Wojtczak
According to the increasing interest in adhesive bonding, the problems of structural health monitoring, diagnostics and quality assessment have become the subject of intensive research. There exists a number of non-destructive testing (NDT) methods, including visual methods, vibration-based methods and wave propagation-based methods (e.g. Rudawska et al. 2016, Barski et al. 2014). One of the rapidly developing NDT area covers techniques based on propagation of ultrasonic waves. There are two fundamental approaches that might be applied for the inspection of adhesive joints. The first is the ultrasonic method dealing with a pressure wave travelling through the thickness of the joint (Figure 1a). The method requires the movement of an ultrasonic probe over the whole scanned area. As a result, a detailed representation of defects in adhesion profiles can be obtained (Korzeniowski et al. 2014). The second approach is based on the guided wave propagation phenomenon (Cuc & Giurgiutiu 2004, Rokhlin 1991, Lanza di Scalea et al. 2001, Puthillath er al. 2008, Castaings 2014). Lamb waves are specific guided waves of numerous applications in non-destructing testing, e.g. in damage detection. They are dispersive waves that occur in media restrained by two parallel surfaces (e.g. thin plates). At the beginning the wave propagates through one adherend as a single-layer mode and then leaks to another by means of mode conversion resulting in wave propagation in three-layer medium (Figure 1b). Based on the interpretation of signals collected after passing through the joint, the condition of the joint can be assessed.
All-Polymer Flexural Plate Wave Devices
Published in Kevin Yallup, Krzysztof Iniewski, Technologies for Smart Sensors and Sensor Fusion, 2017
Christoph Sielmann, John Berring, Suresha Mahadeva, John Robert Busch, Konrad Walus, Boris Stoeber
Lamb waves are traveling waves that propagate along a thin plate. Lamb waves comprise of symmetric and antisymmetric waves, with the latter also being known as FPWs [11]. For a given wavelength and an infinitely thin plate, the symmetric and antisymmetric waves correspond to different frequencies with the symmetric wave frequency typically higher. As the plate thickens such that its thickness exceeds the wavelength of the device, the symmetric and antisymmetric modes merge together to form a SAW with a unique frequency or phase velocity, as shown in Figure 8.2. FPWs have been examined for use in some sensing platforms, but compensating for the temperature sensitivity of the sensor often complicates the design [8,10].
A novel damping based feature for rich resin defect detection in a four layer composite plate using S0 Lamb mode
Published in Nondestructive Testing and Evaluation, 2021
Maryam Shafiei Alavijeh, Mohammad Hossein Soorgee
Structural Health Monitoring (SHM) has been utilised to evaluate the integrity and safety of the structure being monitored since recent decades [8]. Guided Ultrasonic Waves, as one of the most reliable tools for SHM has been employed widely, for several plate-like structures inspection, including vessels, wings, pipes, and other structures made from composite panels [9]. Lamb waves are guided waves which propagate in structures with two free or loaded boundaries. Depending on the structure geometry, different types of damages would be identified or even localised by Lamb waves. Symmetrical and anti-symmetrical modes are two fundamental modes of Lamb waves. Researchers have been widely using Lamb wave-based experiments for SHM [10]. Mall in 2016 observed changes in the phase and group velocity of the fundamental anti-symmetric wave mode in a composite structure with linearly varying thickness [11]. Sohn et al. [9] detected delamination in a specific composite plate using guided wave field image processing. Yelve et al. [12] also investigated delamination in composite laminate based on a Lamb wave nonlinear method. Fucai Li et al. [13] implemented different fibre optic sensors in order to receive Lamb waves in a composite laminate. Several authors in [14–17] have focused on several aspects of ultrasonic Lamb waves inspection methods in composite materials in order to extract suitable features related to damages.
Detection and localization of corrosion using identical-group- velocity Lamb wave modes
Published in Nondestructive Testing and Evaluation, 2023
Liping Huang, Jiawei Ding, Jing Lin, Zhi Luo
Ultrasonic Lamb waves have been considered as a promising and effective tool for accurately identifying defects in metallic and composite structures, because of their long propagation distance and high sensitivity to a variety of defects (such as corrosion, fatigue cracks, delamination) [1–4]. The dispersive and multimodal characteristics of Lamb waves proved to be a two-edged sword. On one hand, they produce a series of spreading wave packets which are of great possibility to interfere with each other, resulting in a highly complex Lamb wave response. On the other hand, each individual Lamb wave mode would interact with defects in distinct ways, carrying abundant information about the structure flaws.
Damage Imaging of Lamb Wave in Isotropic Plate Using Phased Array Delay and Sum Based on Frequency-domain Inverse Scattering Model
Published in Nondestructive Testing and Evaluation, 2022
Compared with conventional methods, ultrasonic technology has been widely used in the field of non-destructive testing with the characteristics of strong penetration, high sensitivity and flexible and convenient operation. The ultrasonic wave propagating in the solid plate and shell structure with small thickness is also called the ultrasonic Lamb wave, which is a plane strain wave generated in the free plate. Lamb wave has the advantages of long propagation and small attenuation and is suitable for large-scale detection. So, it has great potential for non-destructive testing and safety assessment of large plate structures [1].