Quantitative Nondestructive Evaluation Research Articles

Quantitative Nondestructive Evaluation of Cold Spray Manufactured Aluminum Alloy 6061 and Copper Samples

Cold spray (CS) is a solid-state process for depositing thick layers of material via the successive high-velocity impact of powder particles onto a solid surface, which leads to high rates of deformation, interparticle bonding, and coating build-up. Although CS is finding commercial utilization in non-load-bearing repair and coating applications, clear nondestructive characterization procedures are necessary to realize its potential in load-bearing structural applications. In this study, the viability of electrical conductivity and through thickness ultrasound wave velocity measurement methods was studied to serve as a means for nondestructive quantitative measurement for quality control in CS and potentially other additive manufacturing (AM) methods. Eddy current, ultrasound, porosity, hardness, and uniaxial tensile strength tests were conducted on CS deposited layers of aluminum alloy 6061 and copper on aluminum alloy 6061 and commercially pure copper substrates, respectively. CS gas dynamic parameters were intentionally and systematically varied to result in corresponding discrete differences in mechanical properties of deposits. Ultrasound measurements of longitudinal wave velocity and eddy current electrical conductivity measurements showed good correlation with process conditions, microstructural characterization results, and destructive mechanical tests (hardness, tensile). The results of this work show that ultrasound wave velocity and electrical conductivity correlate well with increased particle impact velocity in CS deposited aluminum and copper blocks, which evidently show an incremental decrease in porosity, increase in hardness, and increase in tensile strength. The outlined ultrasound and eddy current nondestructive testing methods present effective means for quantitative assessment of cold spray deposited structures while intact with the substrate.

Non-destructive quantitative evaluation of delamination depth and thickness in GFRP using microwave reflectometry

Glass fiber reinforced polymer (GFRP) laminates are extensively used across various engineering fields. However, the occurrence of internal delamination defects during its production and usage can severely jeopardize equipment safety. Consequently, there's a pressing need to quantitatively detect both the thickness and depth (i.e., the distance from the delamination defects to the GFRP laminates' surface) of these delamination defects. To date, most research efforts fall short in providing an evaluation method that concurrently addresses both defect thickness and depth. In this study, we introduce a far-field quantitative evaluation method based on microwave propagation theory. Unique microwave reflection signals emerge due to variations in defect thickness and depth. By utilizing these distinct signals and incorporating parameters such as signal frequency, defect dimensions, GFRP plate thickness, and its permittivity, we developed a model that relates echo signals to defect characteristics. This model serves as an effective tool for defect detection and quantification. Simulations and experiments validate that our method can simultaneously detect and quantify defect depth and thickness through a single reflection signal. By monitoring changes in microwave reflectivity amplitude, we successfully detected and quantified delamination defect of 30 μm. The quantitative error for defect depth remains below 0.15 mm, with an average error of 0.048 mm. Meanwhile, the error for defect thickness does not exceed 10 μm, averaging at 3.75 μm. Importantly, the theoretical minimum detectable value can reach several microns. Furthermore, this method's detection accuracy remains little affected by the stand-off distance, offering a notable advantage in practical applications.

Extraction and selective promotion of zero-group velocity and cutoff frequency resonances in bi-dimensional waveguides using the electromechanical impedance method

This study showcases the electromechanical impedance (EMI) technique for extracting and promoting zero-group velocity (ZGV) and cutoff frequency resonances in a waveguide structure. We identify the mechanisms of multiple resonances in the EMI spectra via a wave propagation perspective. Both simulation and experiments reveal the fact that sharp resonances in the conductance spectra are associated with either ZGV or cutoff frequency points. Consequently, we design four test configurations to enhance local resonances by aligning induced motions with considered mode shapes. Reasonable agreement between simulation and experiment results is observed. We evaluate the performance of considered configurations in terms of mode enhancement, and configurations that can selectively promote certain mode families are summarized. This study also shines the light on the EMI technique for quantitative non-destructive evaluation (NDE) by potentially supporting the inverse characterization of mechanical properties of host structures.

Qualitative to Quantitative Non-Destructive Evaluation: A Concept for D-Sight Inspections of Aircraft Structures

Non-destructive evaluation of structures is a key procedure in operation of aircraft structures, necessary to maintain their quality and integrity. Numerous non-destructive testing (NDT) techniques have been adapted to inspect aircraft structures and are currently used according to appropriate protocols. However, many of them provide only qualitative results, such as the D-Sight optical NDT technique used for inspections in aviation. In this study, a concept of improvement of the D-Sight technique is proposed by means of appropriate experimental program and processing procedures applied to the resulting images from inspection. It was demonstrated that appropriately selected processing methods may allow assessing damage quantitatively and improve the overall sensitivity and applicability of a given NDT technique.

A magnetoelectric-ultrasonic multimodal system for synchronous NDE of surface and internal defects in metal

In the field of non-destructive evaluation (NDE) of solid metal materials, it has been a challenge to detect surface and internal defects simultaneously by using a single physical mechanism technique. Conventionally, different testing techniques, in which each one is particularly sensitive to a certain type of defect, are employed to gain full defect information. However, a separated testing method is always a time-consuming and laborious work. Here, we report a magnetoelectric-ultrasonic hybrid transducer and multimodal system for quantitative NDE of metal, which integrates a magnetoelectric composite wrapped with a coil for generating alternating current field and simultaneously measuring magnetic abnormal of surface defects (referred to as ME-ACFM) and a dual-piezoceramic ultrasonic transducer (DP-UT) for generating acoustic pulses and detecting the echo signal of internal defects, respectively. A bipulse signal with different pulse widths is used for excitation of the hybrid transducer, in which one is corresponded to the resonant frequencies of 5 MHz for DP-UT, and another to 122 kHz for ME-ACFM. The huge difference between two resonant frequencies is helpful for restraining signal interference each other. Experimental investigations show that when scanning the tested specimens (standard steel No.45 and aluminum plates), the surface and internal defects information can be obtained simultaneously almost without a dead zone. The surface defect resolutions of 0.1 mm width and 0.1 mm depth, and the inside defect resolution of 2 mm blind hole are obtained; the experimental errors for surface defect (crack) depth up to 5 mm are around 5 %; while experimental errors for ultrasonic depth measurement (with a blind zone of 1.25 mm) is less than 0.63 mm. The proposed hybrid transducer and multimodal system open up a new way for designing multi-physical mechanism based NDEs.

Nondestructive evaluation of porosity in additive manufacturing by laser ultrasonic surface wave

A noncontact and nondestructive method based on laser ultrasound is proposed for evaluation of porosity in additive manufacturing components. The 304L stainless steel samples with porosities in the range of 0.1%–5.7 % were fabricated using selective laser melting. Laser ultrasonic surface wave was used to characterize the porosity by the wave speed, peak frequency and wavelet packet energy. The result indicates that the surface wave speed, peak frequency and wavelet packet energy are sensitive to the slight variation of porosity in the samples. Good R-squares of fitting between surface wave velocity and porosity were obtained when it considers the pore irregular morphology. The peak frequency of surface wave decreases as the disappearance of high-frequency signals induced by the scattering attenuation. The wavelet packet analysis result shows that the sum of the percentage energy of the ninth layer of wavelet packet decomposition nodes 2–4 is linearly related to the porosity, and exhibits the highest coefficient of determination (R = 0.98) among the proposed characteristics. It is concluded that the laser ultrasonic surface wave based on wavelet packet energy is recommended to be a promising candidate for the quantitative nondestructive evaluation of the porosity of additive manufacturing components.

Nondestructive evaluation of carburized layer depth in furnace tubes of Cr35Ni45NbMA using magnetic field distortion and magnetic attraction force measurement methods

The ability of magnetic field distortion (MFD) and magnetic attractive force (MAF) sensors to detect both the inner and outer carburized layers of the furnace tube was investigated in the study. They were employed for quantitative nondestructive evaluation of carburized layer depth in furnace tubes of Cr35Ni45NbMA. It was found that the carburized layer on the outer surface had the dominant effect on the responses of MFD and MAF sensors compared to the carburized layer on the inner surface. Parabolic dependency of the responses of MFD and MAF sensors on the carburized layer at the outer surface was concluded. The accuracy of the proposed sensors was verified by experiments. It was found that MFD sensor was more suitable for the detection of the outer carburized layer of furnace tube than MAF sensor, while PSD obtained by MAF could be used for qualitative evaluation of the depth of inner carburized layer.

Modal pencil method for the radiation of guided wave fields in composite plates of finite size

Quantitative prediction of guided wave fields (GW) radiated by ultrasonic sources in parts is a generic problem whose solutions are important in many applications of quantitative non-destructive evaluation (NDE) and structural health monitoring (SHM). NDE and SHM methods relying on GW are very challenging to optimize due to the complexity of GW propagation. This is all the more difficult since composite materials are concerned and since the finite size of the piece cannot be ignored. A simulation tool for choosing the most appropriate transducer in a given application, for optimally positioning transducers by considering the actual testing configuration etc., would be most valuable to practitioners. In order to develop such a tool, a semi-analytical model is derived to predict the modal radiation by an arbitrary source of surface stress of guided waves in a finite anisotropic plate. Considering arbitrary source of surface stress allows us to cover most ultrasonic sources. Considering composite plates of finite size allows us to deal with configurations of industrial interest involving complex wavepaths from the source to field points. Considering modal solutions allows one to more easily interpret complex waveforms. This model combines and generalizes an approximate model predicting the modal Green's function for GW in an infinite anisotropic plate and an approximate model predicting the modal Green's function for GW in a finite isotropic plate. It is validated by comparing its predictions to those computed by a time-domain finite element code for elastodynamics.

Ultrasound in situ characterization of hybrid additively manufactured Ti6Al4V.

A major barrier for the full utilization of metal additive manufacturing (AM) technologies is quality control. Additionally, in situ real time nondestructive monitoring is desirable due to the typical high value and low volume of components manufactured with metal AM. Depending on the application, characteristics such as the geometrical accuracy, porosity, defect size and content, and material properties are quantities of interest for in situ nondestructive evaluation (NDE). In particular, functionally tailored components made with hybrid processing require quantitative NDE of their microstructure and elastic properties. Ultrasonic NDE is able to quantify these relevant characteristics. In this work, an ultrasonic measurement system is used to collect in situ real time measurements during the manufacturing of samples made with a hybrid process, which combines directed energy deposition with milling. In addition to quantifying ultrasonic properties, the measurements are used to gather insight on other geometry, material, and process effects. The results show the utility of ultrasound to evaluate relevant properties during manufacturing of a functionalized material domain, while providing perspective on additional material evolution information obtained from ultrasonic signals.

Quantitative non-destructive evaluation of CFRP delamination defect using laser induced chirp-pulsed radar photothermal tomography

In this paper, a new depth-resolved tomography approach titled laser induced chirp-pulsed radar photothermal tomography (CR-PT) is introduced, and it is employed for the 3D visualization detection for carbon fiber reinforced polymer (CFRP). Initially, the time delay correlation dual orthogonal demodulation (DOD) algorithm is applied to extract the time/frequency-domain characteristic sequence of the chirp-pulsed radar signal, and the applicability of CR-PT is analyzed by COMSOL simulation environment. Subsequently, the correctness of the simulation analysis is verified by the experiment of detecting CFRP with the flat bottom holes by CR-PT. Meanwhile, the accuracy of the shape, position, and depth of the defects detected by CR-PT is determined. Finally, the immersion ultrasonic C-scan imaging and CR-PT are employed to compare and analyze the delamination defect of CFRP composites, which proved the superiority of CR-PT. The experimental results illustrated that CR-PT technique can achieve high-quality 3D geometric reconstruction of CFRP delamination defect, which provides a new attempt and method for quantitative non-destructive evaluation and tomography of CFRP composites.

Special Issue: The 47th Review of Progress in Quantitative Nondestructive Evaluation (QNDE 2020)

Abstract This special issue of the ASME Journal of Nondestructive Evaluation, Diagnostics and Prognostics of Engineering Systems (JNDE) has selected papers from the 47th Annual Review of Progress in Quantitative Nondestructive Evaluation (QNDE 2020) which was held virtually on August 25 and 26, 2020. Papers selected for this special issue have gone through rigorous selection and review process. First, conference session chairs recommended two papers with potential to be journal papers. Authors of these papers were invited to further develop their conference papers into the journal quality papers. All received manuscripts were reviewed following the journal's rigorous review process. The final selected papers represent the classical and contemporary disciplines of importance to NDE, diagnosis and prognosis of engineering systems covered in the conference. We are grateful to the JNDE editorial board, conference track organizers, session chairs, authors, reviewers and ASME journal publication staff, for making this publication possible. Tribikram Kundu, University of Arizona, QNDE 2020 Conference Chair Henrique Reis, University of Illinois at Urbana Champaign, QNDE 2020 Conference Co-Chair Gary Georgeson, Boeing Corporation, QNDE 2020 Conference Co-Chair

Fiber Optic-Based Thermal Integrity Profiling of Drilled Shaft: Inverse Modeling for Spiral Fiber Deployment Strategy.

The current state of practice to interpret the thermal integrity profiling (TIP) data of drilled shaft is the so-called effective radius method. It uses the concrete pouring log and average temperature to construct a relationship between temperature distribution and effective radius that can be used to reconstruct a drilled shaft model. While this effective radius method is computationally inexpensive and has good operationality, it is not good at predicting the dimensions and shape of shaft defects. Upgrading the sensor used in conventional TIP from thermocouples/thermal wires to fiber optic sensors, the spatial resolution of the measured temperature will be enhanced. By using the newly proposed spiral fiber deployment strategy, we can improve the reconstruction of shaft defects in the integrity testing of drilled shafts. The corresponding inverse modeling of defected shaft reconstruction for spiral deployment is proposed in this paper based on the temperature distribution pattern that is learned from forward modeling. Through inverse modeling, the details of defects in drilled shafts can be reconstructed numerically. An analysis of the results shows that the prediction by inverse modeling has good agreement with the forward modeling set up initially. This work helps the evolution of the TIP from the nondestructive testing stage to the quantitative nondestructive evaluation stage.

An SMFL-based non-destructive quantification method for the localized corrosion cross-sectional area of rebar

The non-destructive quantitative evaluation of the rebar corrosion degree is an urgent problem to be solved for corroded reinforced concrete structures. In this study, a non-destructive quantification method for the rebar localized corrosion cross-sectional area was proposed based on the dynamic linkage mechanism of the induced magnetic and self-magnetic flux leakage fields of rebar. As verified by data from the experiment and the finite element simulation, this quantification method could eliminate the adverse influence of the magnetic property differences of the rebar. The results indicated that different quantitative indices for corrosion evaluation could be created based on this method, and an index created by two transformations with the same geometric characteristics had better quantification capability. The four quantitative indices I1, I2, I3, and I4 created in this study were all linearly related to the rebar localized corrosion cross-sectional area ratio S, and index I3 had the relatively best quantitative capability and applicability. This quantification method provided an innovative solution for the non-destructive quantitative evaluation of rebar corrosion.

Thermoelastic stress analysis as a method for the quantitative non-destructive evaluation of bonded CFRP T-joints

Adhesive bonding is a material joining process in which an adhesive, placed between the surfaces, solidifies to produce a strong bond. In this regard, adhesively bonded joints represent an interesting alternative to mechanical joints and provide many advantages over conventional mechanical fasteners: continuity of the structure, high strength-to-weight ratio, design flexibility, and easiness of fabrication.In the present research, the Thermoelastic Stress Analysis (TSA) technique has been used as a non-destructive tool for evaluating the mechanical behaviour of aeronautical adhesive bonded CFRP T-joints made by automated fibre placement process. Moreover, the thermoelastic signal was used for determining the debonded areas after the pull-off tests. The results in terms of the measured debonded area were compared to the well-established lock-in thermography technique. The capability of the Thermoelastic Stress Analysis to perform an in-depth study of the quality of T-joints has been demonstrated.

Generalized scattering matrix method for Lamb wave scattering analysis at cascaded notches

A thorough understanding of the scattering mechanism of Lamb waves at discontinuities is of interest for quantitative evaluation of structural properties and mode control. This study extends the generalized scattering matrix method to investigate the interaction of straight crested Lamb waves with multiple cascaded rectangular notches. Based on the orthogonality and completeness of Lamb modes, the mode matching method is utilized to determine the scattering matrices of downward and upward step discontinuities. After that, the generalized scattering matrix method is employed to determine the scattering matrices of a single rectangular notch and the recurrence relations between the scattering matrices of n + 1 cascaded notches and those of n cascaded notches. Finally, the scattering matrices of multiple cascaded notches can be easily obtained taking advantage of the recurrence relations. As the number of cascaded notches increases, more and sharper peaks appear in the scattering coefficient curves. The finite element simulations conducted in the time domain validate the theoretical results for cascaded notches with identical or different depths, which demonstrate that this method can be applied to find the scattering coefficients at piece-wise periodic or nonperiodic waveguides. The generalized scattering matrix method may have potential applications in quantitative nondestructive evaluation and mode control.

A new MFL imaging and quantitative nondestructive evaluation method in wire rope defect detection

As a reliable and flexible loading tool, wire rope has been widely applied in various of industries and practical applications. Nondestructive testing and evaluation for wire rope defect inspection have become necessary methods in safety guaranteeing. However, traditional one-dimensional (1D) and two-dimensional (2D) magnetic flux leakage (MFL) signal processing methods for wire rope nondestructive evaluation (NDE) may lead to miss and false detection, especially under complex operation conditions with strong noise interference. Thus, a new MFL imaging and quantitative defect recognition method is proposed. Based on the reshaped sine function, wavelet transformation and grid entropy matrix reconstruction, five different MFL imaging algorithms are presented and compared. Besides, three MFL image processing methods through the Gabor filtering, morphological filtering, and small object feature extraction as well as the quantitative centroid distance calculation are also investigated. Finally, the quantitative evaluation model for wire rope defect inspection is built and tested in the case study and performance comparison, where six groups of wire rope testing signal recognition results not only verify the feasibility and validity of the proposed quantitative methods, but also demonstrate its great application promise in wire rope defect evaluation under sophisticated conditions. Additionally, advantages and disadvantages of the proposed method as well as the future wok are discussed.

Numerical parametric study of Nonlinear Coda Wave Interferometry sensitivity to microcrack size in a multiple scattering medium

This paper reports a numerical study of the sensitivity and applicability of the Nonlinear Coda Wave Interferometry (NCWI) method in a heterogeneous material with a localized microcracked zone. We model the influence of a strong pump wave on the localized microcracked zone as a small average increase in the length of each crack. Further probing of this microcracked zone with a multiply scattered ultrasonic wave induces small changes to the coda-type signal, which are quantified with coda wave interferometry. A parametric sensitivity study of the CWI observables with respect to the changes in crack length is established via numerical simulations of the problem using a 2D spectral element method (SEM2D). The stretching of the signal, proportional to the relative variation in effective velocity, is found to be linearly proportional to the global change in crack length, while the other CWI parameter, the remnant decorrelation coefficient, is found to be quadratically proportional to the crack length change. The NCWI method is shown to be relevant for the detection of different damaged material states in complex solids. The reported numerical results are especially significant in the context of quantitative nondestructive evaluation of micro-damage level of a heterogeneous materials using nonlinear ultrasound signals.

Elimination of cells deviated from human induced pluripotent stem cells with a photoactivatable IR700-labelled antibody

Human induced pluripotent stem cells (hiPSCs) are important starting materials for cell therapy products (CTPs) used for transplantation. During cell culture, hiPSCs often spontaneously undergo morphological changes and lose pluripotency. Such cells are called ‘deviated cells’, which are deviated from the undifferentiated state of hiPSCs, lack the expression of hiPSC markers and become positive for the early differentiation marker SSEA1 (stage-specific embryonic antigen 1, Lewis X glycan). Previously, we identified fibronectin (FN) as a predominant carrier protein of SSEA1 secreted from deviated cells, but not hiPSCs. A sandwich assay using antibodies (Abs) against FN and SSEA1 was developed for non-destructive quantitative evaluation of deviated cells present in hiPSC cultures. In this study, a novel technology was developed to specifically eliminate deviated cells using an anti-FN Ab along with a near-infrared (NIR) photoabsorber, IRDye700DX N-hydroxysuccinimide ester (IR700), which has been used for cancer photoimmunotherapy. The anti-FN Ab conjugated with the IR700 dye (IR700-αFN) bound to and induced the death of deviated cells upon NIR irradiation. In contrast, IR700-αFN failed to stain the hiPSCs, and IR700-αFN/NIR had little or no effect on survival. Finally, IR700-αFN/NIR irradiation induced selective removal of deviated cells from a mixed culture with hiPSCs, demonstrating that the proposed method is suitable for the removal of unwanted deviated cells present in hiPSC culture for the production of CTPs.

Application of the ultrasound control to evaluation of the crack-resistance of low-carbon martensite steel 07Kh3GNMYuA

The goal of the study is to reveal the impact of change in the structural state of steel 07Kh3GNMYuA after heat treatment on the values of the critical stress intensity coefficient (K1c) obtained at a temperature of 50°C and on the velocity of ultrasound wave propagation, as well as to determine a correlation between them for rapid assessment of the crack resistance using acoustic characteristics. The mechanical characteristics of the material and the critical stress intensity coefficient K1c were obtained on the test machine «Inspekt 100 Table». The tangent method is used for determination of K1c. Three samples per K1c value were used in the experiment for a three-point bending scheme at the operating temperature T = –50°C. Acoustic parameters were measured using the echo-pulse method. The results of ultrasonic scanning of heat-strengthened samples made of steel 07Kh3GNMYuA demonstrated the possibility of non-destructive quantitative evaluation of the critical stress intensity coefficient. New data on the mechanical properties of steel 07Kh3GNMYuA and on the correlation between the velocity of longitudinal elastic waves and the values of the critical stress intensity coefficient of structures were obtained. Deviation of the calculated values of K1c obtained using acoustic measurements from the experimental values does not exceed 10%. The proposed model, which explains change in the acoustic characteristics of steel 07Kh3GNMYuA on the basis of phase changes occurring in the steel structure upon tempering, provides conducting of similar studies for other modes of heat treatment and other steel grades. The method is a low labor- and time-consuming procedure for determination of the mechanical characteristics of the products made of steel 07Kh3GNMYuA, since it does not require the manufacturing of samples and their testing. The developed procedure can be proposed for manufacturing application, as the main or additional method for evaluation of the mechanical parameters of materials after various modes of heat treatment.

Nondestructive Quantitative Evaluation of Yarns and Fabrics and Determination of Contact Area of Fabrics Using the X-ray Microcomputed Tomography System for Skin-Textile Friction Analysis.

In different mechanical conditions, repetitive friction in combination with pressure, shear, temperature, and moisture leads to skin discomfort and imposes the risks of developing skin injuries such as blisters and pressure ulcers, frequently reported in athletes, military personnel, and in people with compromised skin conditions and/or immobility. Textiles next to skin govern the skin microclimate, have the potential to influence the mechanical contact with skin, and contribute to skin comfort and health. The adhesion-friction theory suggests that contact area is a critical factor to influence adhesion, and therefore, friction force. Friction being a surface phenomenon, most of the studies concentrated on the surface profile or topographic analysis of textiles. This study investigated both the surface profiles and the inner construction of the fabrics through X-ray microcomputed tomographic three-dimensional image analysis. A novel nondestructive method to evaluate yarn and fabric structural details quantitatively and calculate contact area (in fiber area %) experimentally has been reported in this paper. Plain and satin-woven fabrics with different thread densities and made from 100% cotton ring-spun yarns with two different linear densities (40 and 60 Ne) were investigated in this study. The measurements from the tomographic images (pixel size: 1.13 μm) and the fiber area % analysis were in good agreement to comprehend and compare the yarn and fabric properties reported. The fiber area % as reported in this paper can be used to evaluate the skin-textile interfaces and quantitatively determine the contact area under different physical, mechanical, and microclimatic conditions to understand the actual skin-textile interaction during any physical activity or sports. The proposed method can be helpful in engineering textiles to enhance skin comfort and prevent injuries, such as blisters and pressure ulcers, in diversified application areas, including but not limited to, sports and healthcare apparel, military apparel, and firefighter's protective clothing. In addition, the images were capable of precisely evaluating yarn diameters, crimp %, and packing factor as well as fabric thickness, volumetric densities, and cover factors as compared with those obtained from theoretical evaluation and existing classical test methods. All these findings suggest that the proposed new method can reliably be used to quantify the yarn and fabric characteristics, compare their functionality, and understand the structural impacts in an objective and nondestructive way.