Detectability of Bearing Failure of Composite Bolted Joints by Electric Resistance Change Method

Author(s):  
Yoshinobu Shimamura ◽  
Keiko Oda ◽  
Akira Todoroki ◽  
Masahito Ueda
2005 ◽  
Vol 297-300 ◽  
pp. 653-658 ◽  
Author(s):  
Yoshinobu Shimamura ◽  
Keiko Oda ◽  
Akira Todoroki ◽  
Hideo Kobayashi ◽  
Takaomi Inada

Bolted joints are widely used for composite structures. As is well known, excessive bearing load gives rise to bearing failure at hole boundaries. Detecting bearing failure is important for assuring integrity of composite structures. Conventional nondestructive inspection methods are expensive, cumbersome, time-consuming, and not suitable for health monitoring, and a simple, low-cost inspection method for bearing failure must be developed. Authors have experimentally demonstrated detection bearing failure by an electrical resistance change method. In this study, detectablity of remote damage, which includes bearing failure, using an electric resistance change method is investigated analytically. The results show that fiber breaking and delamination induce permanent increase in the electric resistance of the bolted composite joints, and that the proposed method, which involves measuring electric resistance, is effective for detecting bearing failure.


2006 ◽  
Vol 321-323 ◽  
pp. 957-962 ◽  
Author(s):  
Yoshinobu Shimamura ◽  
Keiko Oda ◽  
Akira Todoroki ◽  
Masahito Ueda

Bolted joints are widely used for composite structures. As is well known, excessive bearing load gives rise to bearing failure at hole boundaries. Detecting bearing failure is important for assuring integrity of composite structures. Since conventional nondestructive inspection methods are expensive, cumbersome, time-consuming, and not suitable for health monitoring, a simple, low-cost inspection method for bearing failure must be developed. Authors have demonstrated the feasibility of detecting bearing failure by using an electric resistance change method. In this study, more detailed analyses were carried out to investigate the detectability in terms of the damage size and the distance between damage and electrodes. The results show that bearing failure of less than 10mm square causes the electric resistance change of a few hundred ppm and thus can be easily detected, and that the electrodes can be mounted more than 10 mm far from a bolt hole.


Author(s):  
Yoshinobu Shimamura ◽  
Keiko Oda ◽  
Akira Todoroki ◽  
Hideo Kobayashi ◽  
Takaomi Inada

2020 ◽  
pp. 002199832097973
Author(s):  
Qijian Liu ◽  
Hu Sun ◽  
Yuan Chai ◽  
Jianjian Zhu ◽  
Tao Wang ◽  
...  

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.


2021 ◽  
Vol 36 (4) ◽  
pp. 417-422
Author(s):  
Y. Hamid ◽  
P. Svoboda

Abstract Ethylene-butene copolymer (EBC)/carbon-fiber (CF) composites can be utilized as an electromechanical material due to their ability to change electric resistance with mechanical strain. The electro-mechanical properties and thermal conductivity of ethylene butene copolymer (EBC) composites with carbon fibers were studied. Carbon fibers were introduced to EBC with various concentrations (5 to 25 wt%). The results showed that carbon fibers’ addition to EBC improves the electric conductivity up to 10 times. Increasing the load up to 2.9 MPa will raise the electric resistance change by 4 500% for a 25% fiber sample. It is also noted that the EBC/CF composites’ electric resistance underwent a dramatic increase in raising the strain. For example, the resistance change was around 13 times higher at 15% strain compared to 5% strain. The thermal conductivity tests showed that the addition of carbon fibers increases the thermal conductivity by 40%, from 0.19 to 0.27 Wm–1K–1.


2000 ◽  
Vol 2000.1 (0) ◽  
pp. 89-90
Author(s):  
Akira TODOROKI ◽  
Hiroshi SUZUKI ◽  
Yoshinobu SHIMAMURA ◽  
Hideo KOBAYASHI

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