scholarly journals Experiment-Based Fatigue Behaviors and Damage Detection Study of Headed Shear Studs in Steel–Concrete Composite Beams

2021 ◽  
Vol 11 (18) ◽  
pp. 8297
Author(s):  
Jun Xu ◽  
Huahuai Sun ◽  
Weizhen Chen ◽  
Xuan Guo
Keyword(s):  
Fatigue Crack ◽  
Fatigue Damage ◽  
Fatigue Failure ◽  
Failure Modes ◽  
Fatigue Loading ◽  
Composite Beams ◽  
Non Destructive Testing ◽  
Destructive Testing ◽  
Non Destructive ◽  
Push Out

Many in-service bridges with steel–concrete composite beams are currently aging and experiencing performance deterioration. Under long-term cyclic loads from traffic on bridges, headed shear studs in steel–concrete composite beams are vulnerable to fatigue damage. The comprehensive understanding of fatigue behaviors and the feasible detection of fatigue damage of headed shear studs is, thus, crucial for the accurate numerical simulation of the fatigue crack propagation process. The paper, thus, experimentally investigates the fatigue behaviors of headed shear studs through push-out tests of three specimens. The fatigue failure modes and cyclic strain evolution of specimens are analyzed. The fatigue lives of headed shear studs are compared with the S–N curves of the AASHTO, Eurocode 4 and BS5400 codes. The fatigue crack details of shear studs in push-out tests are then detected using the ultrasonic non-destructive testing. The results show that the root fracture is the main fatigue failure mode of shear studs under fatigue loading. The fatigue life estimations based on the three current codes (i.e., AASHTO, Eurocode 4 and BS5400) can be safely guaranteed only with different safety redundancies. The strain at the shear stud with fatigue damage shows a consistent increasing trend followed by decreasing behavior after reaching the peak value with the loading cycles. Moreover, the feasibility of the ultrasonic non-destructive testing with the combination of a strain measurement for fatigue crack details detection of headed shear studs in composite beams is proved.

Influence of Crack Retardation on Fatigue Crack Propagation in Steels for Railway Axles

2014 ◽  
Vol 891-892 ◽  
pp. 351-356 ◽  
Author(s):  
Luboš Náhlík ◽  
Pavel Pokorný ◽  
Pavel Hutař
Keyword(s):  
Fatigue Crack ◽  
Fatigue Failure ◽  
Conservative Approach ◽  
Non Destructive Testing ◽  
Destructive Testing ◽  
Testing Method ◽  
Crack Behavior ◽  
Railway Axle ◽  
Crack Retardation ◽  
Non Destructive

The railway axles are subjected to cyclic loading, therefore there is a risk of fatigue failure. For reason that possible crack could not be detected by non-destructive testing method an existing crack in the railway axle must be considered. This is conservative approach commonly used in applications where potential fatigue failure has unaccepted consequences. This paper deals with retardation effect caused by overload cycles and compares results obtained by no retardation approach and results obtained by generalized Willenborg model, which takes into account the retardation effects due to plastic zone around the crack tip. Results obtained can contribute to the better understanding of fatigue crack behavior in railway axles.

Study of Initial Stages of Fatigue Process Using Non-Destructive Testing Methods

2013 ◽  
Vol 592-593 ◽  
pp. 553-556
Author(s):  
František Vlasic ◽  
Josef Volák ◽  
Libor Nohál ◽  
Pavel Mazal ◽  
Filip Hort
Keyword(s):  
Acoustic Emission ◽  
Crack Nucleation ◽  
Electrical Potential ◽  
Fatigue Loading ◽  
Non Destructive Testing ◽  
Testing Methods ◽  
Destructive Testing ◽  
Fatigue Process ◽  
Cyclic Damage ◽  
Non Destructive

This paper deals with the basic research of cyclic damage during the initial stages of fatigue process using the non-destructive testing methods. The acoustic emission method was used for monitoring of the microstructure changes during fatigue loading. The electrical potential measurements of specimen and microscopic observation were used mainly to detect the first short cracks and their propagation. The fatigue tests at room temperature were conducted on titanium alloy and creep-resistant steel specimens under bending and tension loading. The aim of the study was to compare the acoustic emission signal at different types of loading until fracture and to analyze in detail the signal changes in initial stages of fatigue process. This analysis was primarily based on the waveform similarity and division into classes. The results show the high sensitivity of the acoustic emission technology in the transition from the stage of surface relief evolution to the stage of crack nucleation and propagation.

Defect Types and Ultrasonic Nondestructive Testing for Fiber-Reinforced Composites

2013 ◽  
Vol 834-836 ◽  
pp. 233-236
Author(s):  
Lin Dong Liu ◽  
Xiao Qing Wu
Keyword(s):  
Failure Modes ◽  
Fiber Reinforced Composites ◽  
Fracture Mechanisms ◽  
Reinforced Composites ◽  
Non Destructive Testing ◽  
Fiber Reinforced ◽  
Destructive Testing ◽  
The Common ◽  
Non Destructive ◽  
Ultrasonic Ndt

In this paper, an attempt is made to introduce the defect types relevant to ultrasonic non-destructive testing, and then, we explain how these defects generate in fiber-reinforced composites. The common failure modes which occur are described and discussed. The significance of each of the fracture mechanisms, in terms of their effects on the residual load-bearing properties, is considered. The second part describes briefly the main relevant ultrasonic NDT methods used to identify these defects and indicates the sensitivity to the different types of defect.

New non-destructive testing approach based on eddy current for crack orientation detection and parameter estimation

2021 ◽  
pp. 1-21
Author(s):  
Mohamed Guesmi ◽  
Salaheddine Harzallah ◽  
Abdellah Kouzou
Keyword(s):  
Eddy Current ◽  
Fatigue Loading ◽  
Magnetic Flux Density ◽  
Non Destructive Testing ◽  
Crack Orientation ◽  
Destructive Testing ◽  
Crack Angle ◽  
Non Destructive ◽  
Angle Orientation

Crack orientation is a vital factor in the behavioral study of fractures, especially the study of crack propagation in structures that are under dynamic or fatigue loading. Indeed, many non-destructive testing (NDT) techniques have been developed recently for the detection of cracks such as the eddy current testing (ECT). However, the crack orientation has not been undertaken into consideration. In this paper, a NDT based on eddy current using 3D finite element modeling, is proposed for the determination of the crack orientation. The idea of this proposed technique benefits from the influences of crack orientation, which can be observed on the components of eddy current and the related magnetic flux density following the x, y axes, for the estimation of the crack angle orientation based on an interpolation criteria. The obtained results through the presented simulation prove the validity of the proposed technique for the detection of crack angle orientation.

Fatigue Property of Steel Q235 Based on Metal Magnetic Memory Testing

2006 ◽  
Author(s):  
Hai Yan Xing ◽  
Jia Zhong Zhang ◽  
Zun Bao Zhao ◽  
Min Qiang Xu ◽  
Ri Xin Wang ◽  
...  
Keyword(s):  
Fatigue Damage ◽  
Fatigue Property ◽  
Ferromagnetic Material ◽  
Magnetic Memory ◽  
Non Destructive Testing ◽  
Destructive Testing ◽  
Magnetic Metal ◽  
Tangent Component ◽  
Magnetic Induction Intensity ◽  
Non Destructive

Fatigue damage is the most common kind of failure for metal materials. Traditional non-destructive testing (NDT) methods fail to predict early fatigue damage. Magnetic Metal Memory (MMM) Testing, a new NDT technology, has the potential of fatigue damage evaluation. This paper aims to investigate fatigue mechanical property of ferromagnetic material with the MMM method. Steel Q235 samples with different depth and breadth artificial crack are tested in rotary bending fatigue machinery. The MMM fatigue features are as follows: the tangent component Hp(x) of magnetic induction intensity is gradually increasing up to the peak value while the fatigue crack is initiating and growing; after that peak, Hp(x) is descending with the crack deepening. Furthermore, the features have been studied theoretically.

Study on the characteristics of magneto acoustic emission for mild steel fatigue

2020 ◽  
Vol 378 (2182) ◽  
pp. 20190586
Author(s):  
Gongtian Shen ◽  
Yongna Shen
Keyword(s):  
Acoustic Emission ◽  
Crack Propagation ◽  
Fatigue Damage ◽  
Domain Walls ◽  
Stage Ii ◽  
Non Destructive Testing ◽  
Noisy Environments ◽  
Destructive Testing ◽  
Two Stages ◽  
Non Destructive

Fatigue life of materials or structures can be classified into three stages: fatigue hardening or softening, crack initiation and crack propagation, which includes two stages. Current mature non-destructive testing (NDT) methods can only detect macro or visible cracks in stage II crack propagation. In order to detect and evaluate the fatigue damage occurring before stage II crack propagation quickly and effectively, magneto acoustic emission (MAE) measurement was carried out on laboratory specimens with different numbers of fatigue cycles. With the accumulation of fatigue damage, the RMS of MAE decrease steadily on the whole, making MAE a promising non-destructive method for evaluating fatigue damage. To make MAE applicable in noisy environments, square waveform voltage were selected to excite magnetic fields, and ‘T' type MAE signals with higher amplitude were produced. The variation of MAE with number of fatigue cycles at different excitation intensity indicated that the defects associated with fatigue damage have greater effects on the creation and annihilation of domain walls. The point where the MAE amplitude begins to increase instead of decrease with fatigue can be an indicator for the onset of stage II crack propagation. This article is part of the theme issue ‘Advanced electromagnetic non-destructive evaluation and smart monitoring'.

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