scholarly journals On-Site Health Monitoring of Composite Bolted Joint Using Built-In Distributed Eddy Current Sensor Network

Materials ◽  
2019 ◽  
Vol 12 (17) ◽  
pp. 2785 ◽  
Author(s):  
Qijian Liu ◽  
Hu Sun ◽  
Tao Wang ◽  
Xinlin Qing
Keyword(s):  
Numerical Simulation ◽  
Sensor Network ◽  
Eddy Current ◽  
Failure Modes ◽  
Unidirectional Composite ◽  
Bolted Joints ◽  
Induced Voltage ◽  
Hole Edge ◽  
Exciting Coil ◽  
Array Sensing

There is an urgent need to monitor the structural state of composite bolted joints while still remaining in service; however, there are many difficulties in analyzing their strength and failure modes. In this paper, a built-in distributed eddy current (EC) sensor network based on EC array sensing film is developed to monitor the hole-edge damages of composite bolted joints. The EC array sensing film is bonded onto the bolt and consists of one exciting coil and four separate sensing coils. Experiments are conducted on unidirectional composite specimens to validate the ability of the EC array sensing film to quantitatively track the damage that occurs at the hole edge and to investigate the performances of the EC array sensing films with different configurations of the exciting coil. Experimental results show that the induced voltage of sensing coil changes only if the damage appears on the laminate structure where that particular sensing coil is located, whereas the induced voltages of the other sensing coils on other laminate plates remain unchanged. Numerical simulation based on the finite element method is also carried out to investigate and explain the phenomena observed in the experiments and to analyze the distribution of the EC around the bolt hole. Both experimental and numerical simulation results demonstrate that the developed EC array sensing film can effectively identify not only whether there is damage at the hole edge but also the damage location within the thickness and quantitative size.

On-site monitoring of bearing failure in composite bolted joints using built-in eddy current sensing film

2020 ◽  
pp. 002199832097973
Author(s):  
Qijian Liu ◽  
Hu Sun ◽  
Yuan Chai ◽  
Jianjian Zhu ◽  
Tao Wang ◽  
...  
Keyword(s):  
Numerical Simulations ◽  
Eddy Current ◽  
Failure Modes ◽  
Bolted Joints ◽  
Bearing Failure ◽  
Monitoring Method ◽  
Current Sensing ◽  
Site Monitoring ◽  
Array Sensing ◽  
Bearing Damage

Bearing damage is one of the common failure modes in composite bolted joints. This paper describes the development of an on-site monitoring method based on eddy current (EC) sensing film to monitor the bearing damage in carbon fiber reinforced plastic (CFRP) single-lap bolted joints under tensile testing. Configuration design and operating principles of EC array sensing film are demonstrated. A series of numerical simulations are conducted to analyze the variation of EC when the bearing failure occurs around the bolt hole. The results of damage detection in the horizontal direction and through the thickness direction in the bolt hole with different exciting current directions are presented by the finite element method (FEM). Experiments are performed to prove the feasibility of the proposed EC array sensing film when the bearing failure occurs in CFRP single-lap bolted joints. The results of numerical simulations and experiments indicate that bearing failure can be detected according to the variation of EC in the test specimen.

A new interleaving eddy current array-based sensing film for fatigue crack quantification of bolted joints

2021 ◽  
pp. 1045389X2199089
Author(s):  
Hu Sun ◽  
Junyan Yi ◽  
Tao Wang ◽  
Yishou Wang ◽  
Xinlin Qing
Keyword(s):  
Fatigue Crack ◽  
Eddy Current ◽  
Edge Crack ◽  
Crack Detection ◽  
Structural Integrity ◽  
Bolted Joints ◽  
Induced Voltage ◽  
Coil Array ◽  
Hole Edge ◽  
Crack Angle

Fatigue crack quantification for bolted joints attracts much attention to determine the structural integrity for aircraft structures. In this paper, a new sensing film with interleaving eddy current array is proposed to evaluate the parameters of the hole-edge crack for single- or multiple-lap bolted joints. In this sensing film, the exciting layer is one coil throughout the hole wall which consists of a one-dimension rectangle coil array in the axial direction connecting in series, while the sensing layer is made up of two interleaving layers with a two-dimensional sensing coil array distributed in the circumferential and axial directions for each layer. Finite element simulation is conducted to study the effect of different crack parameters on the induced voltage of sensing coils. Simulation results reveal that the sensing film has no blind angle of crack detection but a strong capability of quantifying the crack angle, and the arctangent value of the ratio between interleaving coils can be used for estimating the crack angle. After the crack angle is estimated, induced voltages of sensing coils at this angle may be used to track the crack propagation in the axial or radial directions of the bolt hole. Experiments are conducted to verify the feasibility and effectiveness of the new sensing film to monitor the angle, depth, and length of the hole-edge crack of bolted joints.

Failure Monitoring of Bolted Joints by Using Eddy Current Array Sensing Film

2019 ◽  
Author(s):  
HU SUN ◽  
TAO WANG ◽  
QIJIAN LIU ◽  
YISHOU WANG ◽  
XINLIN QING
Keyword(s):  
Eddy Current ◽  
Bolted Joints ◽  
Array Sensing ◽  
Failure Monitoring

Numerical Simulation of Ring-Shape Rock Failure under Compressive Loading

2011 ◽  
Vol 378-379 ◽  
pp. 15-18
Author(s):  
Yong Bin Zhang ◽  
Zheng Zhao Liang ◽  
Shi Bin Tang ◽  
Jing Hui Jia
Keyword(s):  
Numerical Simulation ◽  
Fracture Process ◽  
Failure Modes ◽  
Failure Process ◽  
Compressive Loading ◽  
Orientation Angle ◽  
Crack Orientation ◽  
Ring Specimen ◽  
Ring Shape ◽  
Good Agreement

In this paper, a ring shaped numerical specimen is used to studying the failure process in brittle materials. The ring specimen is subjected to a compressive diametral load and contains two angled central cracks. Numerical modeling in this study is performed. It is shown that the obtained numerical results are in a very good agreement with the experiments. Effect of the crack orientation angle on the failure modes and loading-displace responses is discussed. In the range of 0°~40°, the fracture paths are curvilinear forms starting from the tip of pre-existing cracks and grow towards the loading points. For the crack orientation angle 90°, vertical fractures will split the specimen and the horizontal cracks do not influence the fracture process.

Damage Evolution and Failure Modeling in Unidirectional Graphite/Epoxy Composite

2001 ◽  
Author(s):  
G. P. Tandon ◽  
R. Y. Kim
Keyword(s):  
Damage Evolution ◽  
Failure Modes ◽  
Epoxy Composite ◽  
Damage Model ◽  
Tensile Loading ◽  
Unidirectional Composite ◽  
Concentric Cylinder ◽  
Failure Modeling ◽  
Stress Levels

Abstract A study is conducted to examine and predict the micromechanical failure modes in a unidirectional composite when subjected to tensile loading parallel to the fibers. Experimental observations are made at some selected stress levels to identify the initiation and growth of micro damage during loading. The axisymmetric damage model of a concentric cylinder is then utilized to postulate and analyze some failure scenarios.

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