scholarly journals Active Monitoring of Fatigue Crack in the Weld Zone of Bogie Frames Using Ultrasonic Guided Waves

Sensors ◽  
2019 ◽  
Vol 19 (15) ◽  
pp. 3372 ◽  
Author(s):  
Yan ◽  
Jin ◽  
Sun ◽  
Qing
Keyword(s):  
Fatigue Crack ◽  
Lead Zirconate Titanate ◽  
Fatigue Cracks ◽  
Weld Zone ◽  
Damage Index ◽  
Guided Wave ◽  
Vertical Force ◽  
Active Monitoring ◽  
Bogie Frame ◽  
Railway Vehicles

The bogie frame is an important structure of railway vehicles, transmitting the traction, braking force, lateral force, and vertical force during the traction operation. With the development of high speeds and heavy loads, the appearance of fatigue cracks in the bogie frames is increasing, which reduces the driving life of railway vehicles and even causes serious traffic accidents. Real-time monitoring on the integrity of the bogie is an inevitable requirement for ensuring the safe operation of railway vehicles. In this paper, ultrasonic guided wave-based active structural health monitoring (SHM) was developed to identify the fatigue crack of the bogie frame. Experiments were conducted on a welded T-shape specimen with a thickness of 12 mm. A total of 10 piezoelectric lead zirconate titanate (PZT) disks were mounted around the weld zone of the specimen, five of which were used as actuators, and the other five were used as sensors. Five-peak modulation narrow-band sine waves were input into the actuators to excite the specimen. From the sensor signals, the advanced damage index (DI) was calculated to identify the propagation of the crack. The experimental results demonstrate that crack damage as small as 2 mm in the weld zone of the bogie frame can be successfully detected. Some practical issues for implementing the SHM in real applications, such as crack quantification and environmental compensation, were also discussed.

Guided Wave Acoustic Emission from Fatigue Crack Growth in Aluminium Plate

2006 ◽  
Vol 13-14 ◽  
pp. 23-28 ◽  
Author(s):  
C.K. Lee ◽  
Jonathan J. Scholey ◽  
Paul D. Wilcox ◽  
M.R. Wisnom ◽  
Michael I. Friswell ◽  
...  
Keyword(s):  
Acoustic Emission ◽  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Elastic Waves ◽  
Fatigue Cracks ◽  
Guided Wave ◽  
Experimental Results ◽  
Multiple Reflections ◽  
Alloy Plate

Acoustic emission (AE) testing is an increasingly popular technique used for nondestructive evaluation (NDE). It has been used to detect and locate defects such as fatigue cracks in real structures. The monitoring of fatigue cracks in plate-like structures is critical for aerospace industries. Much research has been conducted to characterize and provide quantitative understanding of the source of emission on small specimens. It is difficult to extend these results to real structures as most of the experiments are restricted by the geometric effects from the specimens. The aim of this work is to provide a characterization of elastic waves emanating from fatigue cracks in plate-like structures. Fatigue crack growth is initiated in large 6082 T6 aluminium alloy plate specimens subjected to fatigue loading in the laboratory. A large specimen is utilized to eliminate multiple reflections from edges. The signals were recorded using both resonant and nonresonant transducers attached to the surface of the alloy specimens. The distances between the damage feature and sensors are located far enough apart in order to obtain good separation of guided-wave modes. Large numbers of AE signals are detected with active fatigue crack propagation during the experiment. Analysis of experimental results from multiple crack growth events are used to characterize the elastic waves. Experimental results are compared with finite element predictions to examine the mechanism of AE generation at the crack tip.

scholarly journals Monitoring of Fatigue Crack Propagation by Damage Index of Ultrasonic Guided Waves Calculated by Various Acoustic Features

2019 ◽  
Vol 9 (20) ◽  
pp. 4254 ◽  
Author(s):  
Hashen Jin ◽  
Jiajia Yan ◽  
Weibin Li ◽  
Xinlin Qing
Keyword(s):  
Fatigue Crack ◽  
Crack Propagation ◽  
Frequency Domain ◽  
Fatigue Crack Propagation ◽  
Guided Waves ◽  
Fatigue Cracks ◽  
Damage Index ◽  
Ultrasonic Guided Waves ◽  
Acoustic Features ◽  
Reliable Technique

Under cyclic and repetitive loads, fatigue cracks can be further propagated to a crucial level by accumulation, causing detrimental effects to structural integrity and potentially resulting in catastrophic consequences. Therefore, there is a demand to develop a reliable technique to monitor fatigue cracks quantitatively at an early stage. The objective of this paper is to characterize the propagation of fatigue cracks using the damage index (DI) calculated by various acoustic features of ultrasonic guided waves. A hybrid DI scheme for monitoring fatigue crack propagation is proposed using the linear fusion of damage indices (DIs) and differential fusion of DIs. An experiment is conducted on an SMA490BW steel plate-like structure to verify the proposed hybrid DIs scheme. The experimental results show that the hybrid DIs from various acoustic features can be used to quantitatively characterize the propagation of fatigue cracks, respectively. It is found that the fused DIs calculated by the acoustic features in the frequency domain have an improved reliable manner over those of the time domain. It is also clear that the linear and differential amplitude fusion DIs in the frequency domain are more promising to indicate the propagation of fatigue cracks quantitatively than other fused ones.

scholarly journals Monitoring of Interfacial Debonding of Concrete Filled Pultrusion-GFRP Tubular Column Based on Piezoelectric Smart Aggregate and Wavelet Analysis

Sensors ◽  
2020 ◽  
Vol 20 (7) ◽  
pp. 2149 ◽  
Author(s):  
Wenwei Yang ◽  
Xia Yang ◽  
Shuntao Li
Keyword(s):  
Remote Sensing ◽  
Real Time ◽  
Lead Zirconate Titanate ◽  
Damage Index ◽  
Pulse Excitation ◽  
Interface Debonding ◽  
Active Monitoring ◽  
Monitoring Method ◽  
Damage Level ◽  
Smart Aggregate

The concrete filled pultrusion-GFRP (Glass Fiber Reinforced Polymer) tubular column (CFGC) is popular in hydraulic structures or regions with poor environmental conditions due to its excellent corrosion resistance. Considering the influence of concrete hydration heat, shrinkage, and creep, debonding may occur in the interface between the GFRP tube and the concrete, which will greatly reduce the cooperation of the GFRP tube and concrete, and will weaken the mechanical property of CFGC. This paper introduces an active monitoring method based on the piezoelectric transducer. In the active sensing approach, the smart aggregate (SA) embedded in the concrete acted as a driver to transmit a modulated stress wave, and the PZT (Lead Zirconate Titanate) patches attached on the outer surface of CFGC serve as sensors to receive signals and transfer them to the computer for saving. Two groups of experiments were designed with the different debonding areas and thicknesses. The artificial damage of CFGC was identified and located by comparing the value of the delay under pulse excitation and the difference of wavelet-based energy under sweep excitation, and the damage indexes were defined based on the wavelet packet energy to quantify the level of the interface damage. The results showed that the debonding damage area of CFGC can be identified effectively through the active monitoring method, and the damage index can accurately reflect the damage level of the interface of GFRP tube and concrete. Therefore, this method can be used to identify and evaluate the interface debonding of CFGC in real time. In addition, if the method can be combined with remote sensing technology, it can be used as a real-time remote sensing monitoring technology to provide a solution for interface health monitoring of CFGC.

Efficient Modeling of Nonlinear Scattering of Ultrasonic Guided Waves From Fatigue Cracks Using Local Interaction Simulation Approach

2016 ◽  
Author(s):  
Yanfeng Shen ◽  
Carlos E. S. Cesnik
Keyword(s):  
Fatigue Crack ◽  
Guided Waves ◽  
Mode Conversion ◽  
Fatigue Cracks ◽  
Guided Wave ◽  
Ultrasonic Guided Waves ◽  
Nonlinear Scattering ◽  
Absorbing Boundary ◽  
Interaction Simulation ◽  
Interior Damage

This paper presents an efficient modeling technique to study the nonlinear scattering of ultrasonic guided waves from fatigue damage. A Local Interaction Simulation Approach (LISA) is adopted, which possesses the versatility to capture arbitrary fatigue crack shapes. The stick-slip contact dynamics is implemented in the LISA model via the penalty method, which captures the nonlinear interactions between guided waves and fatigue cracks. The LISA framework achieves remarkable computation efficiency with its parallel implementation using Compute Unified Device Architecture (CUDA) executed on GPUs. A small-size LISA model is tailored for the purpose of extracting the guided wave scattering features. The model consists of an interior damage region and an exterior absorbing boundary. The interior damage region captures various types of fatigue crack scenarios, while the exterior absorbing boundary surrounds the damage model to eliminate boundary reflections. Thus, the simulation of guided wave scattering in an infinite media can be achieved utilizing a small-size local LISA model. Due to the parallel CUDA implementation and the small-size nature, this local LISA model is highly efficient. Selective mode generation is achieved by coupling/decoupling excitation profiles with certain wave mode shapes, which allows the study of sensitivity of different wave modes to a certain fatigue damage situation. At the sensing locations, mode decomposition is performed on the scattering waves, which enables the study of mode conversion at the damage. Fourier analysis allows the extraction of scattering features at both fundamental and higher harmonic frequencies. A numerical case study on nonlinear scattering of guided waves from a fatigue crack is given. The higher harmonic generation and mode conversion phenomena are presented using the wave damage interaction coefficients (WDIC), from which the sensitive detection directions can be inferred to place sensors. This study can provide guidelines for the effective design of sensitive SHM systems using nonlinear ultrasonic guided waves for fatigue crack detection.

scholarly journals Advanced Ultrasonic Structural Monitoring of Waveguides

2008 ◽  
Vol 56 ◽  
pp. 477-482
Author(s):  
M. Cammarata ◽  
D. Dutta ◽  
Hoon Sohn ◽  
P. Rizzo ◽  
Kent A. Harries
Keyword(s):  
Lead Zirconate Titanate ◽  
Structural Damage ◽  
Fatigue Cracks ◽  
Linear Method ◽  
Damage Index ◽  
High Sensitivity ◽  
Nonlinear Acoustics ◽  
Lead Zirconate ◽  
Discrete Wavelet ◽  
Cross Sectional

Ultrasonic Guided Waves (UGWs) are a useful tool in those structural health monitoring applications that can benefit from built-in transduction, moderately large inspection ranges and high sensitivity to small flaws. This paper describes two methods, based on linear and nonlinear acoustics for structural damage detection based on UGWs. The linear method combine the advantages of UGW inspection with the outcomes of the Discrete Wavelet Transform (DWT) that is used for extracting defect-sensitive features that can be combined to perform a multivariate diagnosis of damage. In particular, the DWT is exploited to generate a set of relevant wavelet coefficients to construct a uni-dimensional or multi-dimensional damage index that, in turn is fed to an outlier algorithm to detect anomalous structural states. The nonlinear acoustics method exploits the circumstance that a cracked medium exhibits high acoustic nonlinearity which is manifested as harmonics in the power spectrum of the received signal. Experimental results also indicate that the harmonic components increase non-linearly in magnitude with increasing amplitude of the input signal. The proposed nonlinear technique identifies the presence of cracks by looking at the harmonics and their nonlinear relationship to the input amplitude. The general framework presented in this paper is applied to the detection of fatigue cracks in an I-shaped steel beam. The probing hardware consists of Lead Zirconate Titanate (PZT) materials used for both ultrasound generation and detection at chosen frequency. The effectiveness of the proposed methods for the structural diagnosis of defects that are small compared to the waveguide cross-sectional area is discussed.

Simulation on the Short Fatigue Crack Initiation of LZ50 Axle Steel for Railway Vehicles

2007 ◽  
Vol 353-358 ◽  
pp. 989-992
Author(s):  
Yan Hai Xu ◽  
Yong Xiang Zhao
Keyword(s):  
Fatigue Crack ◽  
Crack Initiation ◽  
Fatigue Cracks ◽  
Voronoi Tessellation ◽  
Fatigue Crack Initiation ◽  
Stress And Strain ◽  
Railway Vehicles ◽  
Short Fatigue Crack ◽  
Lz50 Steel ◽  
The Given

The short fatigue crack initiation of LZ50 axle steel for railway vehicles was investigated by numerical simulation in this paper. The microstructure of LZ50 steel was constructed with the application of 2D Voronoi tessellation. The stress and strain distributions in the microstructure were obtained by FEM under the boundary condition shifted from loading level applied in fatigue specimen of this steel. Finally, the probability of short fatigue crack initiation was given with different loading cycles to illustrate the process of crack initiation of LZ50 steel under the given loading cycles based on the S-N curve of the material. The further work on the research of crack growth and collective evolution of short fatigue cracks can be conducted with the simulated results of crack initiation in the microstructure of LZ50 steel.

Experimental Research on Damages Detection of Pipeline Structure by Using PZT-Based Waves

2011 ◽  
Author(s):  
Shi Yan ◽  
Binbin He ◽  
Naizhi Zhao
Keyword(s):  
Damage Detection ◽  
Lead Zirconate Titanate ◽  
Smart Materials ◽  
Arrival Time ◽  
Mode Conversion ◽  
Guided Wave ◽  
The Other ◽  
Damage Location ◽  
The Waves ◽  
Peak Value

Pipeline structure may generate damages during its service life due to the influence of environment or accidental loading. The damages need to be detected and repaired if they are severe enough to influence the transportation work. Non-destructive detection using smart materials combined with suitable diagonal algorithms are widely used in the field of structural health monitoring (SHM). Piezoelectric ceramics (such as Lead Zirconate Titanate, PZT) is one of the smart materials to be applied in the SHM due to the piezoelectric effect. So far, the PZT-based wave method is widely used for damage detection of structures, in particular, pipeline structures. A series of piezoelectric patches are bonded on the surface of the pipeline structure to monitor the damages such as local crack or effective area reduction due to corrosion by using diagonal waves. The damage of the pipeline structure can be detected by analysis of the received diagonal waves which peak value, phase, and arriving time can be deferent from the health ones. The response of the diagonal wave is not only correlated to the damage location through estimation of the arrival time of the wave peak, but also associated with the peak value of the wave for the reduction of wave energy as the guided wave passing through the damages. Therefore, the presence of damages in the pipeline structure can be detected by investigating the parameter change of the guided waves. The change of the wave parameters represents the attenuation, deflection and mode conversion of the waves due to the damages. In addition, the guided wave has the ability of quick detecting the damage of the pipeline structure and the simplicity of generating and receiving detection waves by using PZT patches. To verify the proposed method, an experiment is designed and tested by using a steel pipe bonded the PZT patches on the surface of it. The PZT patches consist of an array to estimate the location and level of the damage which is simulated by an artificial notch on the surface of the structure. The several locations and deep heights of the notches are considered during the test. A pair of the PZT patches are used at the same time as one is used as an actuator and the other as a sensor, respectively. A tone burst of 5 cycles of wave shape is used during the experiment. A wave generator is applied to create the proposed waves, and the waves are amplified by an amplifier to actuate the PZT patch to emit the diagonal waves with appropriately enough energy. Meanwhile, the other PZT patch is used as a sensor to receive the diagonal signals which contain the information of the damages for processing. For data processing, an index of root mean square deviation (RMSD) of the received data is used to estimate the damage level by compare of the data between the damaged and the health peak valves of the received signals. The time reversal method which aimed at increasing the efficiency of the detection is also used to detect the damage location by estimating the arrival time of the reflected wave passing with a certain velocity. The proposed method experimentally validates that it is effective for application in damage detection of pipeline structure.

Plastic Slip and Early Stage of Fatigue Damage in Polycrystals: Comparison between Experiments and Crystal Plasticity Finite Elements Simulations

2014 ◽  
Vol 891-892 ◽  
pp. 1711-1716 ◽  
Author(s):  
Loic Signor ◽  
Emmanuel Lacoste ◽  
Patrick Villechaise ◽  
Thomas Ghidossi ◽  
Stephan Courtin
Keyword(s):  
Fatigue Crack ◽  
Finite Elements ◽  
Crack Initiation ◽  
Fatigue Damage ◽  
Crystal Plasticity ◽  
Early Stage ◽  
Low Cycle Fatigue ◽  
Fatigue Cracks ◽  
Fatigue Crack Initiation ◽  
Plastic Slip

For conventional materials with solid solution, fatigue damage is often related to microplasticity and is largely sensitive to microstructure at different scales concerning dislocations, grains and textures. The present study focuses on slip bands activity and fatigue crack initiation with special attention on the influence of the size, the morphology and the crystal orientation of grains and their neighbours. The local configurations which favour - or prevent - crack initiation are not completely identified. In this work, the identification and the analysis of several crack initiation sites are performed using Scanning Electron Microscopy and Electron Back-Scattered Diffraction. Crystal plasticity finite elements simulation is employed to evaluate local microplasticity at the scale of the grains. One of the originality of this work is the creation of 3D meshes of polycrystalline aggregates corresponding to zones where fatigue cracks have been observed. 3D data obtained by serial-sectioning are used to reconstruct actual microstructure. The role of the plastic slip activity as a driving force for fatigue crack initiation is discussed according to the comparison between experimental observations and simulations. The approach is applied to 316L type austenitic stainless steels under low-cycle fatigue loading.

scholarly journals Structural and mechanical defects of materials of offshore and onshore main gas pipelines after long-term operation

2015 ◽  
Vol 5 (1) ◽  
Author(s):  
Pavlo Maruschak ◽  
Sergey Panin ◽  
Iryna Danyliuk ◽  
Lyubomyr Poberezhnyi ◽  
Taras Pyrig ◽  
...  
Keyword(s):  
Fatigue Crack ◽  
Fatigue Life ◽  
Quantitative Analysis ◽  
Stress Concentration ◽  
Cyclic Loading ◽  
Fatigue Cracks ◽  
Preliminary Deformation ◽  
Term Operation ◽  
Steel Pipes

AbstractThe study has established the main regularities of a fatigue failure of offshore gas steel pipes installed using S-lay and J-lay methods.We have numerically analyzed the influence of preliminary deformation on the fatigue life of 09Mn2Si steel at different amplitudes of cyclic loading. The results have revealed the regularities of formation and development of a fatigue crack in 17Mn1Si steel after 40 years of underground operation. The quantitative analysis describes the regularities of occurrence and growth of fatigue cracks in the presence of a stress concentration.

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