Relative Nonlinearity Parameter Research Articles

Assessment of aging degradation in rubber using quasi-static components of ultrasonic longitudinal waves

Abstract Aging degradation is the main form of failure of rubber in service, leading to a decline in its physical and mechanical properties. This paper presents an efficient method for assessing the aging degradation of rubber using the quasi-static component (QSC) of ultrasonic longitudinal waves induced by acoustic radiation. The experiments quantitatively observe the response of the QSC pulse to different levels of ageing degradation. A pulse-echo ultrasonic transducer is employed to simultaneously capture the primary longitudinal wave (PLW) and QSC echoes, enabling the determination of the acoustic nonlinearity parameter of QSC with a single transducer excitation. The results suggest that, in comparison to traditional linear ultrasonic techniques based on attenuation coefficient and wave velocity measurements, the relative acoustic nonlinear parameter of QSC proves to be more sensitive to aging degradation in rubber. Particularly, the amplitude of the QSC pulse undergoes a significant change with increasing aging degradation, even when the PLW tone burst is completely attenuated. These findings confirm the effectiveness of QSC as a method for evaluating aging degradation in highly attenuative materials.

Research on nonlinear ultrasonic method for evaluating the mechanical properties of 3D printing aluminum alloy

Micro defects, such as pore and inclusions, inevitably appear in the forming process of three-dimensional (3D) printed materials, which would affect the mechanical properties of materials. Therefore, a nondestructive testing method is urgently needed to evaluate the effect of these micro defects on the mechanical properties of materials. In the present work, by using a nonlinear ultrasonic testing technology, mechanical test and characterization of material microstructure, the relationship between the relative acoustic nonlinearity parameter (RANP), tensile strength and material defect ratio of 3D printed aluminum alloy specimens under different scanning powers is investigated. The analysis results show that the greater the material defect ratio is, the smaller the tensile strength is and the greater the RANP is, and the RANP could be used to evaluate the strength of materials. Moreover, fatigue damage induced by high cycle fatigue loading test in the first stage of early performance degradation, the results of nonlinear ultrasonic testing show that the RANP presents an increasing trend as the fatigue load increases. By observing changes in material microstructure, it is found that the increasing acoustic nonlinearity parameter is due to the directional coarsening degree of the precipitated phase increasing, which shows that RANP is very sensitive to the change of material microstructure. The above results show that, the nonlinear ultrasonic testing technology can quantitatively evaluate and predict the mechanical performance and early performance degradation of 3D printing aluminum alloy.

Second harmonic generation for estimating state of charge of lithium-ion batteries

This study applied the nonlinear ultrasonic method, second harmonic generation, to precisely estimate the state of charge (SoC) in lithium-ion batteries. The second harmonic of the longitudinal wave is generated on a pouch cell battery at 5 MHz with a through-transmission setup. The relative nonlinear parameter β′ is determined by analyzing the amplitudes at the fundamental and second harmonic frequencies. To enhance the nonlinear parameter's measurement accuracy, multiple excitation amplitudes are employed. Two separate charge/discharge tests (four-cycle and eight-cycle) are conducted on the battery at a rate of C/10. The nonlinear parameter is measured periodically during the charge/discharge process, and temperature compensation is applied to the measurement. The correlation curves between the nonlinear parameter and the actual SoC align well for the four-cycle and eight-cycle tests, and a robust linear relationship is observed for both correlation curves. A linear model and a second-order polynomial model are applied to fit the correlation using all data points from both tests. The two models are employed to validate the SoC prediction on a second battery by using a four-cycle test. The results indicate that both models can predict the SoC with an accuracy of approximately 3%, whereas the polynomial model demonstrates smaller errors in the regions near 0% and 100% SoC. Therefore, the nonlinear parameter β′, measured through the second harmonic generation, can effectively predict lithium-ion battery SoC with an accuracy of less than 3%.

Numerical and experimental investigations on quasistatic pulse generation of ultrasonic guided waves in fiber reinforced composite pipes

The quasistatic pulse (QSP) generation of ultrasonic guided waves in composite pipes can exhibit many features that are useful for early-stage material characterization and structural health monitoring. The intrinsic relationship between the QSP generation and the weak elastic nonlinearity of solids is complex. It has yet promised for developing the nonlinear ultrasonic guided wave technique that combines its advantages of high sensitivity to microdamage and low ultrasonic attenuation in composite materials. This study presents a systematic investigation of the QSP generation in fiber reinforced composite pipes. Using a three-dimensional finite element simulation with a nonlinear material model, the temporal waveform, mode conversion effect, cumulative effect, generation efficiency, and duration effect of QSP generation are revealed. The nonlinear QSP signals in laminated composite pipes are confirmed as the fastest wave mode that only has axial displacement. The shape of QSP depends on the group velocity difference between the QSP and the primary wave. The magnitude of QSP is related to the excitation level, frequency, and tone-burst duration of the primary wave. Experiments are conducted using carbon fiber reinforced composite pipes and the signals are measured using a laser vibrometer scanning system for verifying the QSP generation. The experimental results are consistent with the numerical findings. A relative nonlinear acoustic parameter based on the QSP generation is proposed and used to evaluate the early-stage thermal fatigue damage in the pipes. The measured nonlinear acoustic parameter demonstrates high sensitivity to the damage, indicating considerable potential for industrial applications.

Characterization on vermicular graphite rate and tensile strength in vermicular graphite cast iron based on nonlinear ultrasonic technique

Ultrasonic techniques have been widely used to detect the percentage of vermicular graphite, defects, etc. in vermicular graphite cast iron. The linear ultrasonic velocity method is the main ultrasonic method for characterizing vermicular graphite rate and tensile strength in the current study, however, it is often easy to misjudge the vermicular graphite rate due to its insignificant variation. This study explores the feasibility of using the nonlinear ultrasonic technique (NUT) to characterize the vermicular graphite rate and tensile strength. Based on the longitudinal critically refracted (LCR) wave detection model, an experimental study to detect the vermicular graphite rate and tensile strength of vermicular graphite cast iron is carried out using the nonlinear ultrasonic harmonic method, and compared with the ultrasonic velocity method. The experiment results show that the relative nonlinear parameter of the LCR wave decreases along with the increase of vermicular graphite rate and increases along with the increase of tensile strength, and it has higher detection sensitivity and resolution than ultrasonic velocity by analyzing the obtained data. The increase in the acoustic nonlinearity parameter (ANP) is related to the increase in the number of grain boundaries in the microstructure. Therefore, the relationship among microstructure, ANP, and mechanical properties of vermicular graphite cast iron can be established, and it’s promising that a new approach might be developed for quickly detecting the vermicular graphite rate and corresponding tensile strength with the NUT.

Assessment of early fatigue in solid plates using quasi-static component by Lamb wave propagation under group velocity matching

The aim of this study is to investigate the feasibility of evaluating the degree of early fatigue in solid plates by utilizing quasi-static components (QSC) generated by primary Lamb wave (PLW) propagation. The investigation is carried out through theoretical considerations, numerical simulation, and experimental examination. The paper begins by examining the generation of QSCs by PLW propagation under group velocity matching. Subsequently, a suitable mode pair comprising primary and zero-frequency Lamb waves, which satisfy group velocity matching, is chosen for a given aluminum plate to enable the QSC to accumulate and grow with propagation distance. The aluminum plates are then subjected to tension-tension cyclic loading, and experimental measurements are performed. By measuring the amplitudes of the PLW and the generated QSC at different numbers of loading cycles (N), a quantitative relationship between the relative nonlinear acoustic parameter and N is established. The study demonstrates that the relative nonlinear acoustic parameter increases sensitively and monotonically with the increase in fatigue loading cycles. These experimental results confirm the feasibility of utilizing the group-velocity-matching QSC-based approach to evaluate the degree of early fatigue in solid plates.

Application of Odd Harmonic Resonances of a Single Crystal to Generation and Reception of Superharmonic Waves for Sensitive Monitoring of Heat-Treated Materials.

In nonlinear ultrasonic testing, the quadratic and more recently cubic nonlinearity parameters are frequently measured as a quantitative indicator of damaged material state. Application of higher-order harmonics can improve the sensitivity of detection and monitoring for damages and microstructures due to their higher values of nonlinearity parameters. The excitation and reception of higher-order harmonics, so-called superharmonics, which use the third to fifth harmonics arising from nonlinear wave propagation, is not sufficiently investigated and applied. The purpose of this communication is to develop a highly sensitive superharmonic nondestructive technique that efficiently generates and receives third- and fifth-order harmonics using the odd harmonic resonances of a single piezoelectric crystal. The method focuses on the measurement of fifth harmonic generation and reception, and the calculation of the relative quintic nonlinearity parameter (δ'). The method also addresses the issue of source nonlinearity that may be contained in the measured fifth harmonic amplitude. The measurement results of δ' for a series of precipitation heat-treated samples clearly show a much better sensitivity than the results of the cubic nonlinearity parameter (γ'). The proposed method enables a highly sensitive and true pulse-echo mode nonlinear ultrasound testing.

On the utility of linear and nonlinear ultrasound for evaluating microstructure-property relationships in laser powder bed fusion 316 L stainless steel

Given the complexity and potential for variability in components fabricated with metal additive manufacturing, the need for efficient, reliable, and nondestructive quality assurance is imperative for advancing its utilization in industry. Here, linear and nonlinear ultrasonic testing is used to nondestructively link microscale features and mechanical properties of 21 distinctly-printed AISI 316 L stainless steel samples manufactured by laser powder bed fusion. Groups of samples were heat-treated to induce microstructural changes under as-built, 600 ℃, 900 ℃, and 1100 ℃ conditions. While a linear ultrasonic parameter, wave speed, could not completely differentiate the evolution of microstructure and mechanical properties during heat treatment, the relative acoustic nonlinearity parameter β′ measured with second harmonic generation demonstrated sensitivity to incremental changes in heat treatment temperature, ultimate tensile strength, yield strength, dislocation density, and presence of oxide inclusions. Precise resonance frequency measurements were obtained using a fully noncontact configuration, and shifts in resonance frequency with heat treatment were connected to changes in average grain area and partial recrystallization. The large number of samples and high volume of ultrasonic testing in this study provides insight into part and measurement variability, which is key in demonstrating the feasibility of ultrasonic evaluation as the nondestructive solution for additively manufactured parts qualification.

Highly Sensitive Detection of Microstructure Variation Using a Thickness Resonant Transducer and Pulse-Echo Third Harmonic Generation.

In nonlinear ultrasound testing, the relative nonlinear parameter is conveniently measured as a sensitive means of detecting and imaging overall variation of microstructures and damages. Compared to the quadratic nonlinear parameter (β'), the cubic nonlinear parameter (γ'), calculated as the third harmonic amplitude divided by the cube of the fundamental amplitude, has generally a higher value, providing better sensitivity in nonlinear parameter mapping. Since the third harmonic amplitude is about two orders of magnitude lower than the fundamental amplitude, efficient excitation and highly sensitive reception of third harmonic is very important. In this paper, we explore an odd harmonic thickness resonant transducer that meets the requirements for pulse-echo third harmonic generation (THG) measurements. We also address the problem of source nonlinearity that may be present in the measured amplitude of the third harmonic and propose a method to properly correct it. First, we measure γ' for a series of aluminum specimens using the through-transmission method to observe the behavior of γ' as a function of specimen thickness and input voltage, and examine the effects of various corrections such as attenuation, diffraction and source nonlinearity. Next, we apply the odd harmonic resonant transducer to pulse-echo THG measurements of precipitation heat-treated specimens. It is shown that such transducer is very effective in generation and detection of fundamental and third harmonics under finite amplitude toneburst excitation. The highly sensitive detectability of γ' are presented as a function of aging time, and the sensitivity of γ' is compared with that of β' and β'2.

Quality assessment of adhesive joints using third harmonics of fundamental shear horizontal wave mode

This study aims to investigate the bond quality of aluminum–epoxy–aluminum tri-layer bonds using nonlinear ultrasonics. An experimental methodology was developed in which the tri-layer bonds with different interface qualities were inspected using the fundamental shear horizontal guided wave mode (SH0). An in-house developed magnetostrictive transducer assembly was used to excite the SH0 wave mode in the bonded samples. The harmonic generation of the SH0 wave mode was confirmed using dispersion curves overlaid on short-time Fourier transform (STFT) and frequency–wavenumber plots. The sensitivity of the third harmonics to the interface quality of the bonds was estimated using a relative nonlinearity parameter ([Formula: see text]). In this work, the mean [Formula: see text] for the non-sandblasted bond is found to be 70% more than that of the sandblasted sample, which shows the sensitivity of the third-harmonic generation to the interfacial degradation. The analysis shows that the technique can be implemented for a quick and early inspection of the bonded samples for their bond quality.

Evaluation of Early-Stage Fatigue Damage in Metal Plates Using Quasi-Static Components of Low-Frequency Lamb Waves

Abstract Nonlinear Lamb waves including second harmonic and acoustic-radiation-induced quasi-static components (QSC) have a potential for accurately evaluating early-stage fatigue damage. Most previous studies focus on second-harmonic-based techniques that require phase velocity matching and are hard to isolate interferences from ultrasonic testing systems. The aforementioned requirement and deficiency limit applications of the second-harmonic-based techniques. In this study, a QSC-based technique of low-frequency Lamb waves is proposed for early-stage fatigue damage evaluation of metal plates, which does not need to require phase velocity matching and can remove interferences from ultrasonic testing systems. Both in simulations and in experiments, the primary Lamb wave mode at a low frequency that meets approximate group velocity matching with the generated QSC is selected. In finite element simulations, different levels of material nonlinearities by changing the third-order elastic constants are used to characterize levels of fatigue damage. Numerical results show that the magnitude of the generated QSC pulse increases with the levels of fatigue damage. Early-stage fatigue damage in aluminum plates with different fatigue cycles is further experimentally evaluated. The generated QSC pulse is extracted from received time-domain signals using the phase-inversion technique and low-pass digital filtering processing. The curve of the normalized relative acoustic nonlinearity parameter versus the cyclic loading number is obtained. Numerical simulations and experimental results show that the early-stage fatigue damage in aluminum plates can effectively be evaluated using the QSC generated by low-frequency Lamb waves.

Evaluation of material surface properties using one-way collinear mixing Rayleigh waves

Nonlinear Rayleigh waves are useful for material surface damage detection. Traditional non-destructive testing (NDT) techniques based on higher harmonics of Rayleigh waves are inevitably interfered with by the nonlinearity of measurement systems. To overcome this disadvantage, an approach based on one-way collinear mixing Rayleigh waves (MRWs) is proposed to evaluate the material surface properties. A wedge with two different incidence angles for the excitations of transverse and longitudinal waves is designed to generate one-way collinear MRWs. The one-way collinear MRWs can be generated on the whole surface of the material, and propagate along the propagation way under one excitation. Numerical simulations of one-way collinear MRWs under different surface properties, which are characterized using different third-order elastic constants, are studied on a semi-infinite aluminum. Experiments are also conducted on the aluminum specimen, whose surface is corroded by hydrochloric acid so as to change the material surface properties. Both numerical and experimental results show that the one-way collinear MRWs are generated effectively, and the defined relative acoustic nonlinearity parameter increases with the propagation distance as well as the severity of the material surface damages. The results verify the effectiveness of the proposed MRW-based method and prove that it would be a promising NDT technique for the accurate evaluation of material surface properties.

Structural health monitoring of partially immersed metallic plates using nonlinear guided wave mixing

Metallic plates are important structural components of many liquid containment structures, such as liquid storage tanks and sewer pipes. Time-dependent loads can result in fatigue and degradation of the metallic material. Nonlinear guided wave mixing has been demonstrated to be sensitive to microstructural change at the early stage of material degradation. Previous studies have been carried out using the nonlinear guided wave mixing technique on various structures in gaseous environments. However, its application to structures immersed in liquid has not been explored. This paper numerically and experimentally investigates the nonlinear guided wave mixing in an aluminum plate loaded with water on one side. Experiments are carried out with an empty metal tank and the tank filled with water, respectively. The results show that cumulative generation of harmonics at the sum frequency due to the material nonlinearity of the partially immersed plate can be achieved by mixing the fundamental leaky symmetrical Lamb (leaky S0) waves at two different frequencies. Under the same experimental conditions, the amplitudes of the guided wave signals and the values of the relative nonlinearity parameters on the partially immersed plate are different from their counterparts on the plate without water. Finally, numerical simulations are performed with the material nonlinearity of the test plate simulated by the Murnaghan constitutive model. The numerical results reveal that both the second harmonics and the combination harmonics are sensitive to the material nonlinearity of the plate loaded with water on one side.

Impact damage assessment in patch‐repaired carbon fiber‐reinforced polymer laminates using the nonlinear Lamb wave‐mixing technique

AbstractThis study investigates assessment of the barely visible impact damage (BVID) caused by low‐velocity impact (LVI) in single‐sided patch‐repaired orthotropic carbon fiber‐reinforced polymer (CFRP) laminates using experimental and numerical nonlinear Lamb wave‐mixing techniques. An accurate finite element method (FEM) approach consisting of three analysis steps of LVI, vibration damping, and nonlinear ultrasonic mixing detection is proposed to predict the relationship between LVI damage and nonlinear Lamb wave‐mixing propagation. The LVI step in the FEM simulation is verified by drop‐weight impact tests, and the nonlinear Lamb wave‐mixing detection step in FEM is verified by comparing with the RITEC RAM‐5000 SNAP nonlinear mixing detection system. The BVID of patch‐repaired specimens is assessed with mixing relative acoustic nonlinearity parameters (MRANPs). CFRP laminates repaired with various external patch parameters of different sizes, numbers of layers and stacking sequences are evaluated by the FEM approach. Finally, an optimized patch design in which the MRANPs are the smallest is determined. Therefore, the CFRP laminate containing a hole is recommended to be repaired with a circular three‐layer patch with a radius of 2.5 r and a stacking sequence of [90/90/90].

Relative acoustic nonlinearity parameter variation with local defect resonance frequencies and its different harmonics

In recent times, nonlinear ultrasonic inspection has become a very reliable technique to characterize micro-scale cracks and small-scale delaminations. In this paper, an analytical framework is developed for the orthotropic composite plate to calculate the variation of relative acoustic nonlinearity parameter, a quantitative measurement of nonlinearity at the delamination region. The analytical investigation is justified with numerical and experimental research using a carbon fiber-reinforced polymer (CFRP) plate with three delaminations. Two incident waves are used for excitation, out of which the first wave frequency is varied as local defect resonance (LDR) frequency ( fd), subharmonic LDR frequency (2 fd), second-order superharmonic LDR frequency ( fd/2), and third-order superharmonic LDR frequency ( fd/3) while the second incident wave is taken as a single periodic frequency. Different delamination sizes, positions, and depths were used to understand the second-order relative acoustic nonlinearity parameter ( β2) with other LDR frequencies as well as its harmonics. It has been observed from analytical, numerical, and experimental results that the relative acoustic nonlinearity parameter is maximum at LDR frequencies. It increases in case of surface level delaminations.

Ultrasonic Rayleigh Wave Interrogation of Directed Energy Deposition Ti–6Al–4V Having a Rough Surface

Abstract In-situ monitoring techniques for additive manufacturing are in high demand to help produce reliable parts. The structural integrity of these parts depends on both the presence of flaws and their microstructure. Ultrasonic Rayleigh waves have the potential to identify flaws and assess the local microstructure during directed energy deposition (DED) additive manufacturing processes, but the scattering associated with the surface roughness degrades the ultrasonic signal and must be understood to extract useful information. Herein, the microstructures and surface profiles of DED and wrought Ti–6Al–4V are compared to provide context for measured Rayleigh wave speeds and second harmonic generation. The Rayleigh wave speed and second harmonic generation for DED and wrought Ti–6Al–4V materials having comparable surface roughness are significantly different. The wave speed measured in DED material is 3% slower than in wrought material, and the relative nonlinearity parameter, commonly used to characterize second harmonic generation, is 3.5–6.0 times higher for polished surfaces. Wave speed and second harmonic generation measurements are also made along the hatch and across the hatch for both as-built and glazed DED surfaces. Based on our results, we conclude that in-situ Rayleigh wave linear and nonlinear measurements are possible; although we acknowledge that in-situ angle-beam transducer generation would be challenging, and thus we will investigate pulsed laser generation in future work.

Numerical and Experimental Study of the Effect of the Evolution of Matrix Cracks in Composites on the Nonlinear Ultrasound Response

ABSTRACT Early-onset damage in composite materials consists matrix cracking with certain regularity in distribution. However, the effect of the spatial arrangement of matrix cracks and the relationship between the direction of expansion of the cracks and the incident direction of ultrasound waves on the nonlinear parameter in nonlinear ultrasound detection is poorly understood. This study analyzes the nonlinear variation of matrix millimeter-scale and micron-scale cracks by experiment and finite-element-based numerical calculation to improve the damage evaluation of composite materials by nonlinear ultrasound and provide a reference for crack expansion prediction and imaging. The results show that millimeter and micron cracks follow the same trend, with more cracks and “dislocated” spatial arrangement, both providing positive contributions to the relative nonlinear parameter. However, when the incident direction of the ultrasound waves is orthogonal to the crack expansion direction, the evolution of the relative nonlinear parameter will follow an opposite trend with respect to the expansion size compared to when the incident direction and crack expansion direction are the same. We also propose a new nonlinear index (DI), the evolution of which can be used to identify the type of spatial distribution of the cracks in the matrix.

Early damage detection of metallic plates with one side exposed to water using the second harmonic generation of ultrasonic guided waves

Metallic plates are the main structural components in a wide range of thin-walled structures under extreme operational conditions, such as nuclear cooling pipes, pressure vessels, rocket fuel tanks, and submarine hulls. These structures operate in extreme environments and are subjected to transient and repetitive loads. Real-time health monitoring of these structures is indispensable because they are vulnerable to fatigue and corrosion damage. Second harmonic generation is one of the reliable damage detection approaches to evaluate microstructural evolution and has been successfully applied to characterize initial damage on different structures in gaseous environments. However, there have been very limited studies on the second harmonics generation on the structures submerged in liquid. This paper experimentally and numerically investigates the feasibility of using second harmonic generation to evaluate the material degradation of metallic plates with one side exposed to water. The fundamental leaky symmetric Lamb wave mode (leaky S0) at low frequencies is selected because it has low-attenuation and weakly dispersive features, enabling approximate internal resonance. The experimental results show that the second harmonics of leaky S0 waves grow linearly with the propagation distance. The growth rate of the relative nonlinearity parameter (β′) can be related to the material nonlinearity of the one-side water-immersed plate. In addition, this study proposes a three-dimensional (3D) finite element (FE) model to simulate the generation of second harmonics in the one-side water-immersed plate. The material properties of the plate are modeled by the Murnaghan strain energy function. The Murnaghan constants of aluminum that describe the material nonlinearity at different fatigue levels are obtained from a previous experimental study. The simulation results demonstrate that the values of β′ change significantly with the material properties of the one-side water-immersed plates in the initial stages of fatigue damage. Thus, it can be concluded that the second harmonic generation techniques can be used for early damage detection of metallic plates with one side exposed to water.

Investigation on characteristics of tensile damage and microstructure evolution of steel AISI 316L by nonlinear ultrasonic Lamb wave

In view of the high sensitivity to microstructure evolution of higher harmonics generated by the nonlinear ultrasonic method, the tensile damage in the stainless steel AISI 316L was evaluated by nonlinear ultrasonic Lamb wave. The effect of different degree of tensile deformation on nonlinear ultrasonic response in 316L was analyzed by considering the microstructure evolution and the test results. First, the power-law relation of nonlinear ultrasonic parameter and plastic strain is proposed. Meanwhile, martensitic transformation and the increasing of dislocation density can be observed in the micrographs of specimens with the increase of plastic deformation. Then, the same variation tendency of intergranularly averaged Kernel Average Misorientation (KAM), as well as the relative nonlinear ultrasonic parameter, demonstrated that the nonlinearity due to tensile damage is controlled by the evolution of microstructure that directly affects higher order elastic constant of stainless steel 316L. Furthermore, based on continuous damage mechanics, the method quantitatively characterizes the degradation of mechanical properties was proposed with a functional relation of damage variable and relative nonlinear parameter. The method proposed in this study provides a theoretical basis for online monitoring of the damage status of in-service equipment. It is of great significance for residual life assessment, structure integrity assessment, and service life extension of equipment.

Characterization of interfacial property of a two-layered plate using a nonlinear low-frequency Lamb wave approach

This work investigates the feasibility of using a nonlinear low-frequency Lamb wave approach for characterizing the interfacial property of a two-layered plate. Compared with the case of the exact phase-velocity matching, the approximate phase-velocity matching in the low-frequency region can still guarantee the cumulative second-harmonic generation (SHG) of primary Lamb wave propagation, which overcomes the drawbacks arising from the inherent dispersion and multimode features of Lamb wave propagation. For a given two-layered plate, the appropriate mode pair at low frequency consisting of primary Lamb wave and double-frequency Lamb wave (DFLW), which satisfies the approximate phase-velocity matching and nonzero energy flux, is selected to ensure that the amplitude of the generated second harmonic grows within the maximum cumulative distance (MCD). Meanwhile, the numerical analyses indicate that the variation of the SHG efficiency is maximized at the MCD during the interfacial degradation. Using the nonlinear ultrasonic measurement-based experimental setup, the time-domain signal of the second harmonic generated at different propagation distances is conveniently extracted, and then the relative nonlinear acoustic parameter curve consistent with the theoretical prediction is obtained. For examining the influence of interfacial property on the SHG effect of low-frequency Lamb wave propagation, the different annealing cycles of the thin adhesive layer (acrylics) are used to simulate minor changes in the interfacial property of the given two-layered plate. It is found that the relative nonlinear acoustic parameter at the MCD decreases monotonically and sensitively with the increment of annealing cycle number, which verifies the quantitative correlation between the SHG efficiency of low-frequency Lamb wave propagation and the degree of the interfacial degradation. The consistency between the numerical analysis and the experimental measurement shows the potential of using the SHG effect of low-frequency Lamb wave propagation to characterize a minor change in the interfacial properties of a layered composite plate.