Piezoelectric Lead Zirconate Titanate Research Articles

Adhesive curing effect of bonded piezoelectric transducer on electromechanical impedance-based concrete structural damage detection

Complete understanding of the adhesive curing effect of a bonded piezoelectric lead zirconate titanate (PZT) sensor on the electromechanical admittance (EMA, inverse of impedance) facilitates the accurate diagnosis of structural damages when employing the impedance technique for structural health monitoring. This article analytically and experimentally investigated the curing effect of adhesive layer on the EMA-based concrete structural damage detection. Curing effect was theoretically incorporated into shearing mechanism of adhesive layer to formulate a new one-dimensional PZT-structural impedance model. Analytical analysis of the curing effect on the EMA signature as well as the EMA-based damage diagnosis was calculably interpreted through the model. Proof-of-concept experiment was performed on testing a four-point bending reinforced concrete (RC) beam bonded with multiple PZT patches under adhesive curing. Experimental results demonstrated that singular shift in the EMA spectra under adhesive curing could be turned into three typical shifts when structural damage occurred, which cogently validated the analytical results. Quantifiable signal index further provided useful information for the identification of crack occurrence, progression, and reinforcement yielding of the RC beam. Results of this study potentially promoted the real-life engineering applications of impedance technique inclusive of deficient adhesive condition.

Adhesively bonding a reusable PZT transducer for structural health monitoring (SHM) with an ethylene-acrylic acid copolymer adhesive

A novel approach to bonding a piezoelectric lead zirconate titanate (PZT) transducer on a structure for health monitoring was developed to replace the traditional method of bonding PZT permanently. Several experiments demonstrated the feasibility of a reusable PZT transducer based on the adhesive film made using ethylene-acrylic acid copolymer (EAA). Additionally, the adhesion performance of using EAA for bonding PZT at different temperatures and the effect of heating temperature on reusable PZT transducer removal from the test structure was investigated. The effect of adhesive thickness on the mechanical property and the performance of PZT has also been explained. Experimental results showed that the optimized heating temperature of the adhesive film was around 140 °C due to the stability of PZT being sensitive to high temperature and the ease of removing PZT from the test structure without damage. An analysis of the varying thickness of the adhesive layer on PZT performance indicated that the amplitude of Lamb wave signals changed with adhesive thickness, increasing with greater adhesive thickness. Therefore, the adhesive layer made using EAA provides a new approach to conducting Lamb wave-based structural health monitoring.

Monitoring of three-dimensional resin flow front using hybrid piezoelectric-fiber sensor network in a liquid composite molding process

In this paper, a hybrid piezoelectric-fiber sensor network is developed to monitor the three-dimensional resin flow front of thick composite parts in the vacuum assisted resin infusion (VARI) process. Three different approaches based on non-invasive and integrated piezoelectric lead-zirconate-titanate (PZT) sensor network are developed to detect the three-dimensional resin flow front globally. To check the location of the invisible three-dimensional flow front inside the preform, multiple fiber optic sensors are embedded as flow sensors in different layers. The measurements from the piezoelectric and fiber optic sensor networks are then combined as a complement of each other to estimate the three-dimensional resin flow front. The applicability of the proposed hybrid sensor network is investigated on a thick carbon fiber reinforced plastic specimen with three different thicknesses at different locations. Experimental results confirm that the hybrid piezoelectric-fiber sensor network is capable of successfully estimating the three-dimensional flow front in situ and in real-time, achieving smart health monitoring.

Enhanced energy harvesting performances of flexible piezoelectric nanocomposite based on CNTs@PZT nanofibers network

Flexible organic/inorganic piezoelectric nanocomposites are highly demanded for flexible wearable electronic devices due to their excellent mechanical flexibility and high piezoelectric performance. However, the output performance of ceramic-polymer-based piezoelectric nanogenerators (PENGs) is restricted by the poor electrical conductivity of the organic matrix and the distinct discrepancy in mechanical strength between inorganic filler and organic matrix. Herein, we propose a flexible piezoelectric polymer nanocomposite based on CNTs@PZT nanofibers (NFs) network where the carbon nanotubes (CNTs) were introduced into the piezoelectric lead zirconate titanate (PZT) NFs to simultaneously improve the electrical conductivity and mechanical strength of nanocomposites. When subjected to a periodical bending deformation, the CNTs@PZT NFs network-based PENG with optimal addition of CNTs (0.6 wt%) generates a maximum electrical output up to ∼12.5 V and ∼80 nA cm−2 which is four times higher than that of PENGs without CNTs doping. An ultrahigh power density of 91.7 nW cm−2 is obtained with an external load resistance of 40 MΩ when pressed via a 10 N compressive force, and furthermore, the generated power could charge a capacitor and further light a commercial LED. This work may pave a new way for the development of high-output nanocomposite-type PENGs.

Multi-material fused filament fabrication of flexible 3D piezoelectric nanocomposite lattices for pressure sensing and energy harvesting applications

Flexible three-dimensional (3D) piezoelectric sensors and energy harvesters are in great demand for wireless and low power consumption human health monitors, artificial skins and soft robots. In this work, a multi-material fused filament fabrication (FFF) 3D printing technique is used to fabricate 3D piezoelectric and flexible nanocomposite structures with integrated electrodes by utilizing a developed piezoelectric nanocomposite filament and a commercially available conductive nanocomposite filament. The developed piezoelectric nanocomposite filament consists of flexible polyurethane (TPU) matrix and 30 vol% (maximum allowable content) of piezoelectric ceramic lead zirconate titanate (PZT) nanoparticle fillers. The fabricated and poled TPU/30vol%PZT piezoelectric nanocomposite has an elongation at break strain ∼56% and a d33 value 6.8 pC/N. Four types of 3D piezoelectric nanocomposite lattices including simple cubic, body-centered cubic, cuboctahedron and octet truss are fabricated and tested along with a fully dense solid counterepart. Under the same maximum applied compressive force, the octet truss piezoelectric nanocomposite lattice generates two times higher voltage output than the fully dense solid counterpart. As a demonstration for the potential applications, a multi-material 3D printed flexible piezoelectric nanocomposite shoe sole made of the octet truss infill pattern can generate a peak-to-peak voltage (Vpp) ∼20 V through a typical human stomp. Our approach can open a new avenue for design and manufacturing of flexible piezoelectric devices for sensing and energy harvesting applications.

Automated identification of compressive stress and damage in concrete specimen using convolutional neural network learned electromechanical admittance

For the first time, this paper proposed a simple two-dimensional convolutional neural network (2-D CNN) integrated with electromechanical admittance (EMA, inverse of impedance) to detect compressive stress and load-induced damages of concrete cubic structure subjected to applied loading, which was attempted to solve the difficulty for stress/damage quantification merely based on traditional EMA technique. It automatically resolved the raw EMA signatures with no need of complex transformation or manual feature extraction. In the experimentation, the whole process of the structural states from initial loading to fatal failure was monitored via using surface-bonded piezoelectric ceramic lead zirconate titanate (PZT) transducer. Independent EMA databases were established at each stress/damage state of the structure. Qualitative detection of stress development and cracking damage progression as three stages of failure mode was analysed via using characteristics of EMA spectra encompassing resonant frequency and amplitude values. Quantifiable assessment of stress level and damage severity was attempted using the raw EMA signatures learned by the proposed CNN model without signal pre-processing. Experimental results demonstrated that EMA signature was sensitive to stress variations in concrete and its cracking, expansion and propagation. The proposed approach possessed excellent accuracy and efficiency superior to traditional root mean square deviation (RMSD)-based one for quantification on compressive stress and damage state changes in the specimen, which potentially provided an alternative paradigm of data-driven stress/damage identification in concrete structures.

Electromechanical impedance-based concrete structural damage detection using principal component analysis incorporated with neural network

This paper proposed an electromechanical admittance (EMA, inverse of impedance)-based concrete structural damage detection (SDD) approach using Principal Component Analysis (PCA) algorithm incorporated with neural network (NN). First, the PCA algorithm was applied to extract essential feature of the original EMA data obtained from an active piezoelectric lead zirconate titanate (PZT) transducer through data compression. Second, the extracted principle components were adopted as input of a generated NN model to enhance damage prediction ability of the EMA technique. Third, after a sufficient training of NN model using the PCA-processed data, structural damage in term of severity and location could be automatically predicted. Feasibility of the approach was evaluated via conducting an experiment on detecting crack damages in concrete cubic structure, performance of the NN model was analyzed using randomly varied different ratios of training dataset as well. Experimental results demonstrated that the proposed approach gives around 100% accuracy for crack identification, which provided an alternative paradigm of data-driven damage detection in concrete structures.

Multi-Physics Mesoscale Substructure Analysis on Stress Wave Measurement within CFST-PZT Coupling Models for Interface Debonding Detection.

In recent years, the development of interface debonding defect detection methods for concrete-filled steel tubes (CFSTs) using stress wave measurement with piezoelectric-lead-zirconate-titanate (PZT) actuator and sensor has received significant attention. Because the concrete core in CFSTs is a heterogeneous material with randomness at the mesoscale, the size, position and distribution of aggregates unavoidably affect the stress wave propagation and the PZT sensor response. In this study, to efficiently investigate the influence of the mesoscale structure of the concrete core of CFSTs on the response of embedded PZT sensors, a multi-physics substructure model of CFST members coupled with a PZT actuator and a PZT sensor, where a single circular aggregate with different size and position and randomly distributed circular aggregates are considered, are established first. Then, multi-physics simulations on the effect of the local mesoscale structure of the concrete core on the response of the embedded PZT sensor excited by both a sinusoidal signal and sweep frequency signal are carried out. Moreover, corresponding multi-physics and mesoscale simulations on the embedded PZT sensor response of substructures with different interface debonding defects are also carried out for comparison. The amplitude and the wavelet packet energy of the embedded PZT sensor response of each mesoscale substructure are employed to distinguish the influence of the concrete core mesoscale structure and interface debonding defect on sensor measurement. The findings from the results with the multi-physics coupling substructure models are compared with those of the full CFST-PZT coupling models and the tested members of the previous studies to verify the rationality of the embedded PZT sensors measurement of the established substructure models. Results from this study show that the effect of interface debonding defect on the amplitude and the wavelet packet energy of the embedded PZT sensor measurement of the CFST members is dominant compared with the mesoscale heterogeneity and randomness of the concrete core.

Corrosion assessment in rebars of high-strength concrete using electromechanical impedance technique

The corrosion of steel rebar in reinforced concrete structures is one of the main reasons for early deterioration and premature failure of concrete structures, leading to enormous restoration costs worldwide infrastructure restoration. In the past, many sensors and techniques have been developed to monitor corrosion in steel rebar. However, the Electromechanical Impedance (EMI) technique using the piezoelectric Lead Zirconate Titanate (PZT) patches has been immersed as a promising technique to detect damages at an incipient level. This paper presents the corrosion assessment in embedded rebar in high-strength concrete using surface-bonded PZT patches through the EMI technique. The High Yield Strength Deformed (HYSD) rebars of Fe415 grade embedded in high-strength M60 grade concrete cylindrical specimens were used for the experimental work. The artificial corrosion in the embedded rebar was simulated through the accelerated corrosion test for 180 days. The conductance signatures were acquired through a surface-bonded PZT patch on embedded rebar. First, qualitative and quantitative corrosion assessment was carried out based on the conductance signature and the Root Mean Square Deviation (RMSD). Second, the effectiveness of extracted equivalent parameters was demonstrated for capturing the degradation of stiffness and mass due to corrosion. Finally, the corrosion rate is evaluated through equivalent parameters, and a comparison was made with the actual mass loss. The experimental study demonstrated that the EMI technique could be used very effectively through the statical index RMSD and equivalent parameters to identify corrosion phases and resulting losses in stiffness and mass of the structure.

The Feasibility Study of Quantitative Flaw Detection of Grouted Sleeve Connection by Ultrasonics

Grouted sleeve connection has been widely used to connect rebars in prefabricated concrete (PC) structures. Due to the complexities of materials and internal configurations, the flaws or defects are inevitable, which may cause the negative impact on the mechanical properties of reinforcement sleeve connection, ultimately leading to the hidden risk in the PC structures. It is challenging to explore a reliable and efficient flaw detection method for the grouting sleeve. In this paper, an active grout defects detection approach for grouted sleeve connectors using UT wave measurement is proposed, where piezoelectric-lead-zirconate-titanate (PZT) transducer are mounted on surface of the sleeve as transmitter and receivers; and experimental study is carried out to validate the feasibility of the proposed method. In order to investigate the effect of grout defects on UT wave measurement, five grouted sleeve specimens with different degrees of the artificial grout defects are designed and analysis on the PZT transducer was used for measurement. By comparing the PZT transducers measurement of different specimens with different grout defects under an identical impulse excitation signal, the grout defect is detected. Experimental results indicate grout defect leads to decrease in PZT transducers measurement UT energy, the relationship between the UT energy ratio and the internal grouting flaws is established: the UT energy decreases with the increment of flaw size. Therefore, the UT method provides a feasible option to evaluate the internal flaws of grouted sleeve connection.

Anisotropy of magnetoelectric effects in a planar heterostructure comprising a piezoelectric substrate and a ferromagnetic grating

Anisotropic magnetoelectric (ME) effects are investigated in a planar multiferroic heterostructure consisting of a piezoelectric lead zirconate-titanate substrate and a grating of ferromagnetic Ni-strips electrodeposited on its surface. The heterostructure is placed in a tangential dc magnetic field H and excited by an alternating magnetic field h at the frequency of bending acoustic resonance. It is shown that the magnitudes of both the linear and nonlinear ME effects depend on the orientation of the h and H fields with respect to the axis of Ni-strips and the distance between the strips. Strong anisotropy of ME effects arises due to demagnetization in a single Ni-strip and dipole-dipole interaction between the adjacent strips. The calculation technique is proposed that qualitatively well describes the anisotropy of linear and nonlinear ME effects in the heterostructure. The anisotropic ME effect can be used to create magnetic field sensors sensitive to the field orientation.

Real-Time Life-Cycle Monitoring of Composite Structures Using Piezoelectric-Fiber Hybrid Sensor Network.

In this paper, an in situ piezoelectric-fiber hybrid sensor network was developed to monitor the life-cycle of carbon fiber-reinforced plastics (CFRPs), from the manufacturing phase to the life in service. The piezoelectric lead-zirconate titanate (PZT) sensors were inserted inside the composite structures during the manufacturing process to monitor important curing parameters, including the storage modulus of resin and the progress of the reaction (POR). The strain that is related to the storage modulus and the state of resin was measured by embedded fiber Bragg grating (FBG) sensors, and the gelation moment identified by the FBG sensors was very close to those determined by dynamic mechanical analysis (DMA) and POR. After curing, experiments were conducted on the fabricated CFRP specimen to investigate the damage identification capability of the embedded piezoelectric sensor network. Furthermore, a modified probability diagnostic imaging (PDI) algorithm with a dynamically adaptive shape factor and fusion frequency was proposed to indicate the damage location in the tested sample and to greatly improve the position precision. The experimental results demonstrated that the average relative distance error (RDE) of the modified PDI method was 68.48% and 46.97% lower than those of the conventional PDI method and the PDI method, respectively, with an averaged shape factor and fusion frequency, indicating the effectiveness and applicability of the proposed damage imaging method. It is obvious that the whole life-cycle of CFRPs can be effectively monitored by the piezoelectric-fiber hybrid sensor network.

Life-cycle health monitoring of composite structures using piezoelectric sensor network

The vacuum-assisted resin infusion (VARI) technique provides considerable advantages in manufacturing large-scale composite structures. An accurate and consecutive structural health monitoring system is urgently required to determine the initial quality and assess the structural integrity of a composite structure. In this paper, a real-time active smart diagnostic system (SDS) based on piezoelectric sensor network is proposed to monitor the whole life-cycle of composite structures. Experiments were conducted on carbon fiber reinforced plastic specimens with different thicknesses to investigate the monitoring capability of piezoelectric lead-zirconate-titanate (PZT) sensors used in the SDS approach. The PZT sensor networks inserted inside the composite structures during the VARI process are used to monitor not only the curing parameters, but also the health status of composite structures when they are in service after curing. To monitor the curing process only, the sensor network can also be installed on the bottom of the mould. Experimental results demonstrate that both 3D resin flow and degree of cure in the VARI process can be effectively monitored by the PZT sensor network. Meanwhile, the embedded PZT sensor network has the potential to identify the different stages in the curing process. It is obvious that the piezoelectric sensor network will provide important technical support for composite materials with the structure and function integrated.

Study on pre-damage diagnosis and analysis of adhesively bonded smart PZT sensors using EMI technique

The electro-mechanical impedance technique (EMI) is one of the best methods for continuous structural health monitoring (SHM) by embedding a smart piezoelectric ceramic Lead Zirconate Titanate (PZT) sensor or pasting it over the surface of the structure. The smart PZT transducer is intensely affected by the adhesive bonding condition between the PZT patch and the host structure. The current paper studies the damage-diagnosis process of the coupled electro-mechanical behavior of an adhesively bonded smart PZT transducer. The inverse of impedance signatures is used for investigating pre-damage diagnosis and analysis of surface-mounted PZT transducer. A parametric study on the variation of adhesive property is carried out to overcome the shear lag effect. The novel contribution of this paper discusses a methodology for an early diagnosis of damage in the PZT transducer and adhesive bond layer during the SHM process. Firstly, the damage is introduced to the PZT patch and bonding layer, and the corresponding EMI signatures are obtained using numerical modeling and simulations. The damage detection using susceptance is discussed for lower frequencies from 0 to 20 kHz. It is observed that the change in susceptance signature is not large enough to detect adhesive debonding. Subsequently, the conductance signatures are utilized for the investigation. It is observed that damage in the adhesive layer and PZT patch cause upward or downward shift with no alteration along the horizontal direction. It helps to detect sensor breakage and adhesive debonding effectively. Secondly, the simulation results are verified using the theoretical analysis for the single piezo configuration by improved continuum-based impedance equations. A modified dual piezo configuration is investigated to validate the proposed method. Experimental investigation on PZT-bonded aluminum plate involving perfectly bonded, adhesive debonding, and sensor breakage conditions are conducted to verify the process. It is found that the real part of the admittance signature is reliable and critical in sensor diagnosis, and sensor faults of debonding and breakage can be identified and differentiated. It also validates the semi-analytical work results. Therefore, the proposed methodology for pre-diagnosing damage present in the smart PZT sensor and adhesive layer using the EMI technique can be utilized for effective SHM.

Magnetoelectric Ferrite–Piezoelectric Heterostructure With Coil-Free Excitation for DC Magnetic Field Sensing

Abstract The paper describes a new planar multiferroic ferrite-piezoelectric heterostructure that implements the coil-free ex-citation of the direct magnetoelectric (ME) effect. The heterostructure contains a magnetostrictive nickel-zinc ferrite layer with a conducting electrode on its surface and a layer of piezoelectric lead zirconate-titanate, mechanically coupled to each other. The ME effect is excited by passing an alternating current with an amplitude of up to 100 mA through the electrode, which creates an excitation magnetic field in the ferrite layer. A bias dc magnetic field of 0-500 Oe is applied tangentially to the ferrite layer. The ME voltage coefficient of E 42 V/(Oecm) is obtained at the acoustic resonance frequency of the heterostructure of 186 kHz. The sensitivity of the structure to the permanent magnetic field reaches 4.6 mV/Oe and depends on the excitation current and orientation of the bias field. Implementation of heterostructures with coil-free excitation makes it possible reducing of size and power consumption, and improving the electromagnetic compatibility of ME magnetic field sensors.

Global and local area inspection methods in damage detection of carbon fiber composite structures

The paper presents multiple impact damage detections and characterization in a multi-layered carbon fiber reinforced polymer structure using a multi-step combination of the global area and local area damage detection methods. A global area analysis using laser Doppler vibrometer (LDV) with piezoelectric lead zirconate titanate (PZT) actuator-based guided waves (GW) excitation was used to detect and locate the damage. The GW full wavefield (FWF) mode conversion and root mean square (RMS) based LDV studies helped to visualize the impact crack damage (ICD) when tested at varying excitation frequencies. The experimental results were cross-verified numerically using the spectral element method (SEM). The implemented structural health monitoring (SHM) based sectorial elliptical code (SEC) reduced the overall calculation time in damage localization and accurately identified the damage from experimental and numerical data. An infrared thermography (IRT)-based crack identification algorithm was developed in pinpointing the ICD shape. The automatic method removes the influence of high heat sources and highlights the damage zones easily. The accuracy of the localization strategy was successfully verified with non-contact active IRT analysis. The crack size and damage severity were quantified using the ultraviolet radiation (UVR) method with a solution mixture based organic dye. The global area method allows detecting possible damage, validated and quantified with the non-destructive testing (NDT) techniques.

Modeling, identification and optimization of damage deterioration in the bolted repaired metallic plate

The in situ detection of the damaged aluminum alloy plate with bolted patch is numerically and experimentally studied based on a surface-mounted piezoelectric ceramic lead zirconate titanate (PZT) elements. The contact effects between the bolts, repair patch and host structure are considered. The convergence analysis, range-frequency analysis and pretension force analysis are discussed. The numerical results are good agreement with those of the experiments. The damage identification indexes are introduced for damage detection. It indicates the numerical simulation is effective for the damage deterioration of bolted repaired structures. The location of the PZT transducer is discussed to optimize the process.

Structural Integrity Assessment of Composites Plates with Embedded PZT Transducers for Structural Health Monitoring.

Active sensing using ultrasonic guided waves (UGW) is widely investigated for monitoring possible damages in composite structures. Recently, a novel diagnosed film based on a circuit-printed technique with piezoelectric lead zirconate titanate (PZT) transducers has been developed. The diagnostic film is a replacement for the traditional cable connection to PZT sensors and has been shown to significantly reduce the weight of the host structure. In this work, the diagnosed films were embedded into composite structures during manufacturing using a novel edge cut-out method during lay-up, which allowed for edge trimming after curing. In this paper, the effect of fatigue loading on the integrity of PZT transducers is initially investigated. The electro-mechanical impedance (EMI) properties at different fatigue loading cycles were used as the diagnostic measure for the performance of the sensors. At the same time, the behaviours of UGW were investigated at different fatigue loading cycles. It was found that the EMI properties and active sensing behaviours remained stable up to 1 million cycles for the force ranges of 0.5~5 kN and 1~10 kN. Next, the effect of embedding the diagnosed film on the mechanical properties of the host composite structure was investigated. Tensile and compressive tests were conducted and the elastic modulus of composite coupons with and without embedded PZT diagnosed films were compared. The elastic modulus of composite coupons with PZT diagnosed films embedded across the entire coupon reduced by as much as 20% for tensile tests and just over 10% for compressive tests compared to the coupons without embedded sensors. These reductions are considered the worst-case scenario, as in real structures the film would only be embedded in a relatively small area of the structure.

A directional continuous wavelet transform of mode shape for line-type damage detection in plate-type structures

Line-type damage is abundant in engineering structures that have been in service for a long time. Vibration-based nondestructive testing as a global method has been extensively used in structural damage identification. In this study, a two-dimensional directional continuous wavelet transform (2D-DCWT)-based damage identification algorithm using “Morlet2d” wavelet for line-type damage detection in plate structures is presented. An analytical long narrow notch-type damage model of simply-supported plates is proposed to evaluate line-type damage effect on plate vibration performance. Based on the proposed model, the biggest challenge in parameter selection of wavelet analysis is solved. The fundamental aspects of 2D-DCWT algorithm in term of notch location and orientation are assessed. A multi-mode shape fusion approach is presented to make the 2D-DCWT algorithm apply to the high-order mode shapes. A comparative study with isotropic “Mexcan-hat2d” wavelet-based damage identification is performed, and it demonstrates that the proposed 2D-DCWT algorithm is superior in noise immunity. The efficiency and practicability of the 2D-DCWT algorithm are certified by an experimental modal test on damage detection of an artificially-induced notched aluminum alloy clamped plate using excitation-response system of the Piezoelectric Leadzirconate-Titanate (PZT) and Scanning laser Doppler Vibrometers (SLDV). As demonstrated in both the analytical and experimental investigation, the suggested approach may successfully identify line-type damage in plate-type structures.

Direct-write piezoelectric coating transducers in combination with discrete ceramic transducer and laser pulse excitation for ultrasonic impact damage detection on composite plates

In this work, direct-write piezoelectric transducers (DWTs) were made by spraying piezoelectric poly(vinylidene fluoride-co-trifluoroethylene) coating with comb-shaped electrodes on carbon fibre reinforced polymer (CFRP) plates for drop weight impact damage detection. Their ability and performance were investigated and compared to discrete piezoelectric lead zirconate titanate (PZT) ceramic transducers that were adhesively bonded on the same CFRP plate. Guided wave signals were acquired with different combinations of actuator-sensor involving DWT, PZT and laser ultrasonic excitation, in pitch-catch configuration. DWTs allowed consistency and simplified signal interpretation due to an effective mode selection (A0 or S0 mode) with wavelengths of 10 and 12 mm. PZTs generated stronger but much more complex signals and mode selection with a larger wavelength (20 mm). The configuration with PZT as actuator and DWT as receiver showed the highest signal amplitude changes of A0 or S0 mode, allowing efficient detection of damage introduced by a 31 J impact. Further ultrasonic B- and C-scans revealed a 27 mm long crack on the plate’s backside developed in addition to internal cracks and delaminations of about 34 mm in length. For realizing contactless ultrasound excitation, a neodymium-doped yttrium aluminium garnet laser (wavelength of 1064 nm, 5.4 ns pulses) was used to replace the surface-mounted brittle PZT. The combination of the broadband laser excitation with the DWTs as sensors achieved more reliable damage detection than equivalent PZTs, attributed to DWT’s effective single mode selection. In addition to reduced weight, the polymeric coated DWTs allow large area implementation (scaling up), even on curved surfaces due to their flexibility and conformability, in contrast to adhesively bonded discrete transducers.