Damage Evaluation Method Research Articles

A damage evaluation method for track structures based on iron pad strain

A damage evaluation method for track structures based on iron pad strain

Quasi-Static Finite Element Analysis and Damage Quantitative Evaluation of Special-Shaped Concrete-Filled Steel Tubular Column Composite Frame Structure

ABSTRACT Based on the elaborate 3D solid finite element (FE) model established by ABAQUS software, a pseudo-static analysis was conducted on a special-shaped concrete-filled steel tubular column composite frame structure. The FE model considers the confinement effect of both the steel tubes and the tensile bars exerting on the core concrete. The results of the numerical analysis concerning failure modes, load-displacement hysteretic curves, load-displacement skeleton curves and stiffness degradation-displacement curves demonstrate a strong correlation with the existing quasi-static test data. Furthermore, an in-depth analysis was conducted on the impact of the axial compression ratio of column on the plastic energy dissipation distribution mechanism. With an axial compression ratio of the column ranging from 0.1 to 0.55, the composite frame structure primarily relies on the energy dissipation of beams, while the columns serve as supplementary support, thereby exemplifying the principle of “strong column-weak beam.” As the axial compression ratio rises to the range of 0.6–0.8, the composite frame structure transitions a “strong beam-weak column” structural system. Combined with the longitudinal compressive strain of the steel tube at the bottom of the column, a quantitative evaluation method for seismic damage is proposed, grounded in indexes of “stiffness damage” and “energy damage.” Then, the threshold values of energy damage and stiffness damage are determined across four distinct levels: “elastic stage in small earthquake,” “elasto-plastic stage in medium earthquake,” “plastic stage in heavy earthquake” and “failure stage.” The proposed method effectively evaluate the damage severity of special-shaped CFT column composite frame structure subjected to seismic events.

Damage evaluation in plain-woven CFRP plate with circular hole under cyclic tensile loading using electrical impedance tomography

Understanding and predicting damage progression within thin plain-woven carbon fiber-reinforced polymer (CFRP) components is an essential issue for scheduling maintenance intervals and structural inspections and typically requires extensive test series. However, uncertainties always remain and result in conservative design and unnecessary downtimes due to the repeated inspections of a healthy structure. Structural health monitoring (SHM) can be used to reduce these uncertainties, as it allows one to evaluate the condition of a mechanical structure during operation. Numerous SHM methods have been developed, which achieve different levels of damage identification but are often investigated at small coupons with nonrealistic structural damages and loading conditions on both structure and sensor. The present research investigates electrical impedance tomography (EIT) featuring an elastoresistive thin-film sensor to evaluate damage that propagates from a circular hole in a large plate under cyclic tensile–tensile multiblock loading. Applied fatigue loads were increased multiple times up to a total number of two million cycles. During the loading, damage initiated at the hole and continuously propagated into the plate. Repeated EIT evaluations of the applied sensor and validating evaluations by means of digital image correlation clearly revealed the robustness of the hardware and the potential of the SHM method for damage evaluation of plain-woven CFRP components.

Study of Deformation Performance and Seismic Damage on Pile-Supported Wharf by Shaking Table Test

Combined with the research results of shaking table test, through the deformation performance of steel pipe pile foundation, the seismic damage and seismic performance of steel pipe high pile wharf are evaluated, and the appropriate evaluation method is given. By setting the numerical analytical model of multi working condition steel pipe high pile wharf with different water depth, different pile types and different pile diameters, the limit displacement of the pile in the soil under different ground motions is calculated. The calculated results show that, the plasticity ratio (defined as μ = δu/δy ) of the structural system of steel pipe high pile wharf ranges from 1.5 to 3.0; and the fitting relationship between plasticity ratio μ and the diameter thickness ratio D/t was obtained. The fitting relationship is tested by the existing experimental research results. The results show that the given fitting relationship can be in good agreement with the experimental results in the range of ± 15%. On the basis of this fitting relationship, taking the diameter thickness ratio as the basic parameter, a seismic damage evaluation method of steel pipe high pile wharf structure based on deformation performance is proposed.

Quantifying Seismic Damage in RC Walls with Image Analysis

ABSTRACT This study presents an image-assisted method for seismic damage evaluation of RC walls, integrating image processing, feature ranking, and machine learning. The method utilizes features from surface crack images, such as crack patterns and ratios, combined with design parameters, to predict damage levels and states. Seismic damage evaluation tools based on damage state, strength degradation, and drift ratio are introduced as indicators for quantifying structural damage. The approach is tested using 450 crack images, and feature selection was applied to identify the most important predictors. The results demonstrate high accuracy with an R-squared of 0.87 and an RMSE of 0.28.

Automated ultrasonic scattering energy method for evaluation of small-sized cracking damage in concrete

The aim of this study was to develop an automatic ultrasonic scattering energy method (USEM) to evaluate small-scale damage to concrete. The automated system measured Leaky Rayleigh waves from the specimens. Herein, the energy of the scattering portion of waves caused by cracks was extracted using a 2D Fourier transform. USEM has the advantage of detecting cracking damage smaller than the applied ultrasonic wavelength, which is problematic when conventional ultrasonic methods are applied to concrete. The proposed methodology was evaluated using laboratory-scale specimens and a concrete bridge exposed to freeze–thaw cycles in the field. The results of the extracted scattering energy demonstrated that the USEM is sufficiently sensitive to detect and localize subwavelength damages of 0.05 mm in concrete. Furthermore, the proposed USEM was compared with conventional ultrasonic pulse velocity with respect to the accuracy of damage detection.

Compression–compression fatigue damage of wrinkled carbon/glass hybrid composite laminates

Compression–compression fatigue tests were carried out to study the compressive fatigue damage mechanisms of a carbon/glass hybrid composite laminate with a manufacturing-induced wrinkle defect. As reported in literature, thin wrinkled composite laminates could show sensibly different fatigue behaviours and damage mechanisms in the presence of tension and compression cyclic loadings. The sensitivities of composites to tension and compression cyclic loadings were not the same. In this study, the damage modes and cracking sequence of a thick wrinkled laminate were identified by the strain fields from digital image correlation (DIC). Acoustic emission (AE) and infrared (IR) thermography were used to detect the damages and explore the potential capabilities of non-destructive evaluation methods when applied to detection of fatigue induced damages in composite structures under operational cyclic loadings. Two primary damage modes were identified and detected before the final failure of the laminate i.e. debonding between the resin-rich layer and the laminate and interlaminar cracks. Debonding occurred earlier than interlaminar cracking. Out-of-plane stresses due to fibre waviness drove the initiation of these damages. Under the settings of AE in this work, AE captured early debonding activities but did not detect the micro damage accumulating before the formation of interlaminar crack. Interlaminar crack initiation was tracked by IR thermography at cross-section of the specimen based on the distinct temperature localisations that occur with this micro damage. No distinct temperature localisations occurred during the formation of debonding as it is mode-I driving under compression–compression cyclic loading, so IR thermography did not detect the debonding crack. The results of this study show the potential of using complementary non-destructive damage evaluation methods to inspect early damages in composite structures. The early detection of damages would give early warning signs before the damages become critical. It is found that AE and IR thermography should be used as complementary tools to detect different damage modes.

Spinal Lesions in Axial Psoriatic Disease: How Should They Be Identified and Quantified by Magnetic Resonance Imaging?

Proper assessment of patients with psoriatic arthritis (PsA) requires assessment of all disease domains, including axial disease. Magnetic resonance imaging (MRI) is the method of choice for evaluating axial involvement in PsA. When assessing patients with PsA for spinal involvement, it is important to assess both vertebral body lesions and posterolateral lesions, such as inflammation in facet joints and costovertebral joints, and enthesitis at spinous and transverse processes. The Canada-Denmark (CanDen) assessment system for spine MRIs is the preferred method for detailed evaluation of inflammation and structural damage at various anatomical locations in the spine, and it is reproducible and sensitive to change. The Assessment of Spondyloarthritis international Society (ASAS) has recently published MRI definitions of inflammatory and structural lesions in the spine, incorporating the CanDen definitions of spinal lesions on MRI. Applying the ASAS definitions and the CanDen assessment system in clinical practice and trials is recommended. Ongoing research/studies, not least the Axial Involvement in Psoriatic Arthritis (AXIS) study, may provide a data-driven definition of axial involvement in PsA. Ongoing research is expected to further improve and validate assessment tools for axial PsA and to provide a much-needed data-driven consensus-based definition of axial involvement in PsA.

Feasibility study of nonlinear ultrasonic imaging using a contact pulse-echo method for fatigue damage evaluation

ABSTRACT A contact pulse-echo nonlinear imaging method is proposed for the detection and localisation of fatigue damage in solid materials. A dual element transducer is designed based on nonlinear wave simulations and manufactured to improve the signal-to-noise ratio of harmonic waves. The transducer is clamped on a fixture device for scanning. The proposed method is introduced for scanning and imaging stainless steel specimens with different fatigue damage states. Experimental results for the specimen in the initial state show that both the fundamental and second harmonic waves are well measured and the imaging of nonlinear parameters is very stable over the scanning area. The imaging results for the specimen with an initial fatigue crack show that the fundamental waves remain the same but the second harmonic waves vary significantly in the potential growth area of the fatigue crack. Furthermore, the imaging results for the seriously fatigued specimen show that the amplitudes of fundamental waves decrease near the fatigue crack, while the amplitudes of second harmonic waves increase. These results indicate that the proposed pulse-echo method is effective for nonlinear ultrasonic imaging and early damage evaluation. The factors affecting the nonlinear waves in the lab experiments and possible problems with practical applications are also discussed for the proposed method.

Target Damage Calculation Method of Nash Equilibrium Solution Based on Particle Swarm between Projectile and Target Confrontation Game

In order to scientifically evaluate the target damage effect of uncertain intersection between projectile and target confrontation game, this paper establishes a basic model of target damage in the intersection between projectile and target game, which is through the spatial relationship between the explosive position of the projectile and the target position and gives a calculation method of target damage evaluation. The study applies Nash equilibrium theory to analyze income-loss functions in an adversarial game model. According to the definition of the possibility degree of interval number in uncertain multi-attribute decision-making, we proposed a method of solving the Nash equilibrium value of the income matrix of both sides of the game, which is using the interval possibility degree. We used quantitative calculations to analyze game strategies and changes in target damage under different states, such as fragment numbers, velocities, and angles of hit in the confrontation game between projectile and target. Based on the Nash equilibrium value solution method of the particle swarm optimization algorithm, we quantitatively calculated the fitness change relationship between the projectile and the target under different strategy sets. Based on the actual projectile confrontation game test, we analyze the damage probability effects of two projectiles at different explosion positions and different rendezvous angle angles on the three cabins. The results show that in the same area, the intersection angle is smaller, the probability of target damage is greater, and the intersection distance is farther, the damage probability is smaller.

Method for the Quantitative Evaluation of Low-Permeability Reservoir Damage in the East China Sea Based on Experimental Evaluation and Modeling Calculation

Reservoir damage is a key factor affecting reservoir evaluation, ensuring stable reservoir production and improving the utilization rate of oil and gas resources. At present, the evaluation of damage caused by reservoir drilling fluid is too empirical, and there is a lack of methods for the high-precision evaluation of reservoir damage after drilling fluid invasion and pollution. In a block in the East China Sea, the production capacity is limited due to an excessive balance of drilling fluid and long exposure time. In order to ensure safe drilling, the dynamic damage mechanism of drilling fluid during drilling was analyzed. The core of the main reservoir of well XH-1 in a block in the East China Sea was selected for carrying out an experiment evaluating the dynamic damage caused by drilling fluid. According to the experimental results, the damage rate of reservoir permeability caused by drilling fluid invasion ranges between 58.25 and 87.25%, and the overall dynamic damage degree can be classified between medium and high. Combined with the experimental parameters, a mathematical model of drilling fluid invasion depth was established, and the calculation formulas of drilling fluid invasion depth and contaminated skin were derived. The results showed that the drilling fluid depth of the reservoir section corresponding to the core of well XH-1 was 0.47~0.83 m, and the contaminated skin factor was 1.22~13.41, which made up for the lack of evaluation methods of reservoir damage caused by drilling fluid and provided a theoretical basis for the optimization of drilling fluid parameters and exploration drilling technology in oilfield operations.

On-line Updated Guided Wave-Based Gaussian Process Method for Damage Evaluation of Aircraft Structure

Accurate damage evaluation for an aircraft by using guided wave-based structural health monitoring (SHM) technology is in critical demand. An aircraft experiences various uncertainties during its service life, such as the time-varying environment, operational conditions, and different flight missions. Additionally, the actual aircraft structure involves complex structural forms such as varied thickness, stiffeners, ribs, and large cutouts, leading to a strong uncertainty of damage initiation and propagation. Consequently, when applied to an individual aircraft structure, the diagnosis model trained by prior data inevitably introduces errors, and the errors accumulate as the damage propagates, which brings challenges in engineering application. To achieve individual aircraft structure’s more accurate damage evaluation, an on-line updated guided wave-based Gaussian process (GP) damage evaluation method is investigated in this paper. Multi-source data from the design, service, and maintenance stages are utilized to continuously update and evolve the GP model, enabling its accurate evaluation throughout the long-term service life.

An equivalent target plate damage probability calculation mathematics model and damage evaluation method

Aiming at the requirement of damage testing and evaluation of equivalent target plate based on the explosion of intelligent ammunition, this paper proposes a novel method for damage testing and evaluation method of circumferential equivalent target plate. Leveraging the dispersion characteristics parameters of fragment, we establish a calculation model of the fragment power situation and the damage calculation model under the condition of fragment ultimate penetration equivalent target plate. The damage model of equivalent target plate involves the fragment dispersion density, the local perforation damage criterion, the tearing damage model, and the damage probability. We use the camera to obtain the image of the equivalent target plate with fragment perforation, and research the algorithm of fragment distribution position recognition and fragment perforation area calculation method on the equivalent target plate by image processing technology. Based on the obtained parameters of the breakdown position and perforation area of fragments on equivalent target plate, we apply to damage calculation model of equivalent target plate, and calculate the damage probability of each equivalent target plate, and use the combined probabilistic damage calculation method to obtain the damage evaluation results of the circumferential equivalent target plate in an intelligent ammunition explosion experiment. Through an experimental testing, we verify the feasibility and rationality of the proposed damage evaluation method by comparison, the calculation results can reflect the actual damage effect of the equivalent target plate.

Revealing evolution law and failure mechanism of interface damage in concrete-encased CFST columns by acoustic emission technology

Concrete-Encased Concrete-Filled Steel Tubular (CFST) has extensive applications in high-rise buildings and bridge engineering as a high-performance composite structure. The severe bond failure between Concrete-Filled Steel Tubular and the outer concrete poses a significant threat to the integrity and safety of the structure. Considering the concealed and random nature of interface damage, this study proposes a real-time monitoring and evaluation method for Concrete-Encased CFST interface damage based on acoustic emission (AE) technology. Four groups of experiments on Concrete-Encased CFST column interface shear was conducted to investigate the influence of the number of shear connectors on the bond failure mechanism between CFST and the outer concrete. The signal characteristics of three kinds of AE sensors with different operating frequency ranges were analyzed to guide the selection of sensors according to the monitoring targets. The structural damage development trend has been recognized by analyzing the change rule of AE feature parameters. RA-AF correlation analysis has been used to identify the evolution law of cracks and the failure mechanism of the structure. The b-value analysis has been used to evaluate the damage severity of the structure. From the above three aspects, the damage evolution law and failure mechanism of the interface can be revealed. The results indicate that the R3α sensor is suitable for early warning of damage, the R15α sensor can be used for monitoring and warning of structural failure, and the R6α sensor can be used to describe and evaluate the whole process of damage. Based on the features of AE hit rate, cumulative hits, and cumulative energy, the damage process of Concrete-Encased CFST column interface can be accurately divided into the elastic stage, local slip stage, shear connector fracture stage, and slip stage. The RA-AF correlation analysis showed that the shear cracks were detected to develop rapidly before the peak load, and a significant number of tensile cracks caused by cracking of the outer concrete appear around the peak load. The changes of b-value can effectively reflect the magnitude of damage and record the occurrence of major damage.

Crack detection and damage evaluation of asymmetrical steel-reinforced concrete frame nodes using acoustic emission technology

ABSTRACT Detecting cracks in steel-reinforced concrete (SRC) frame nodes is crucial for ensuring structural safety. This study employs acoustic emission (AE) technology to monitor the growth of concrete structural defects in real time. The aim is to establish a sensitive assessment method based on AE parameters to accurately assess the damage stages of SRC frame nodes by considering the complex crack extension mechanism in SRC structures. An experimental study of the AE characteristics of SRC frame nodes under low-cycle loading was performed. The crack evolution process of SRC frame nodes was monitored and analysed using the AE parameters. The results showed that ringing count is the AE parameter more sensitive to the damage of the SRC frame node. The damage evaluation method was established based on the variation coefficient analysis of the AE parameters. Considering the sudden change in the growth rate of the damage index, the damage evolution process of the SRC frame nodes can be accurately divided into three stages: initial crack compaction, rapid crack expansion, and crack penetration. These stages are consistent with the mechanical properties of SRC frame nodes.

The pore aggregation characterized by spatial statistics methods and its effect on the damage behavior based on the configurational forces of the M-integral in MOX fuel

MOX fuel is one of the most widely used nuclear fuels in nuclear power plants. Due to the inhomogeneity of Pu, MOX fuel is prone to the formation of Pu-rich agglomerates and the occurrence of pore aggregations during irradiation. This paper aims to obtain microstructural information of the fuel using spatial statistics methods and investigate the impact of pore aggregation on MOX fuel damage based on the configurational forces of the M-integral. Firstly, the pore aggregation model is established by random sequence adsorption method twice, and the relationship between fuel model size and pore diameter is determined by point pattern criteria based on spatial statistics methods. Secondly, through spatial statistics methods, the reliability of the pore aggregation model to characterize different aggregation levels is verified. Simultaneously, it is confirmed that the M-integral delineating the global state is a better indicator of fuel damage compared to physical quantities that delineate the local state. Finally, a damage assessment model based on the M-integral is established by the basic characteristics of MOX fuel. The effects of the volume fraction of Pu-rich agglomerates, the Pu weight fraction within Pu-rich agglomerates and the radial position of the fuel pellet on the fuel damage are analyzed. It is concluded that the concentrated distribution of Pu promotes the damage of MOX fuel. The MOX fuel pellet center suffers the most damage. This study has proposed a damage evaluation method for MOX fuel microstructure with pore aggregation and established a relationship between the spatial distribution of fuel pores and fuel damage.

A Two-step Inverse Method for Quantitative Damage Evaluation of Plate-like Structures Using Vibration Approach

This study presents a novel two-step approach to assess plate-like structural laminar damages, particularly for delamination damage detection of composite structures. Firstly, a 2-D continuous wavelet transform is employed to identify the damage location and sizes from vibration curvature data. An inverse method is subsequently then used to determine the bending stiffness reduction ratio along a specified direction, enabling the quantification of the delamination severity. The method employed in this study is an extension from the one-dimensional inverse method developed in a previous work of the authors. The applicability of the two-step inverse approach is demonstrated in a simulation analysis and by an experimental study on a cantilever composite plate containing a single delamination. The inverse method is shown to have the capacity to reveal the detailed damage information of delamination within a constrained searching space and can be used to determine the effective flexural stiffness of composite plate structures, even in cases of complex delamination damage. Conflict of Interest Statement The authors declare no conflicts of interest.

Data Compression and Damage Evaluation of Underground Pipeline With Musicalized Sonar GMM

The underground cement pipeline network is critical in urban infrastructure, such as sewage drainage, fluid transportation, etc. Pipelines are deeply buried, so the damage is difficult to be detected. It is of great significant to monitor the crack of pipeline in real time. In this research, a data compression and damage evaluation method of underground pipeline using musicalized sonar GMM (Gaussian Mixed Model) was proposed. First, the sonar echo signal was sampled and discretized into four musicalized indicators by musicalized model. Then, the distribution of multi parameters were analyzed by GMM. The Frechet similarity was constructed to compare the difference between each working condition and baseline condition, so that the damage state could be identified. The engineering experiment shown that this method could greatly compress the monitoring data and evaluate four crack levels.

An improved thermal damage evaluation method for lightning-induced failure analysis of overhead ground wire

In the research of lightning-induced damage mechanisms for overhead ground wire (OGW), thermal ablation damage evaluation has always been a basic work. In this paper, a numerical evaluation model of thermal damage for OGW, considering the latent heat of phase transition and mass loss caused by vaporization, is proposed. The influence of the phase transition effect on the thermal damage evaluation results was analyzed, and the damage characteristics under different lightning heat sources were also discussed. Finally, this model was compared with the published experimental data and the OGW damage sample caused by natural lightning strikes, respectively. The results showed that in the case of ignoring the latent heat of phase transition and mass loss, the maximum assessment deviations exceeded 190% and 45%, respectively. Under the continuing current, the thermal ablation damage of OGW was determined by the heat transfer of lightning arc. While under the return-stroke current, the contribution of Joule heat to thermal ablation increases as the current increases. Based on the existing Joule heat & arc heat transfer model, the damage evaluation results considering the phase transition effect were consistent with the reported experimental results. However, it cannot match the OGW damage sample results. This issue deserves further discussion.

Assessment method for 220 kv cable outer sheath damage based on bp neural network

220 kV high-voltage submarine cables find extensive application in offshore wind power transmission systems. Ensuring the safe operation of these cables involves accurately detecting and assessing the extent of damage to the cable sheath. This study begins by constructing a finite element simulation model for the cable based on its actual model. Subsequently, a method for evaluating the cable sheath’s damage state is proposed by using a BP neural network. The network takes ambient temperature, current, and six-point temperatures of the damaged section as input characteristics. Results indicate a correct rate of 94.29% for the BP neural network, demonstrating its effective discrimination of cable sheath damage levels. This approach introduces a novel evaluation method for cable sheath damage.