Nonlinear self-sensing impedance-based fatigue crack detection under a low-frequency vibration

2012 ◽  
Author(s):  
Changgil Lee ◽  
Seunghee Park
Keyword(s):  
Fatigue Crack ◽  
Crack Detection ◽  
Low Frequency ◽  
Low Frequency Vibration ◽  
Fatigue Crack Detection

Development of a tunable low-frequency vibration energy harvester and its application to a self-contained wireless fatigue crack detection sensor

2018 ◽  
Vol 18 (3) ◽  
pp. 920-933 ◽  
Author(s):  
Suyoung Yang ◽  
Sung-Youb Jung ◽  
Kiyoung Kim ◽  
Peipei Liu ◽  
Sangmin Lee ◽  
...  
Keyword(s):  
Fatigue Crack ◽  
Energy Harvesting ◽  
Crack Detection ◽  
Energy Harvester ◽  
Low Frequency ◽  
Vibration Energy ◽  
Low Frequency Vibration ◽  
Resonance Frequencies ◽  
Energy Harvesting System ◽  
Fatigue Crack Detection

In this study, a tunable electromagnetic energy harvesting system, consisting of an energy harvester and energy harvesting circuits, is developed for harnessing energy from low-frequency vibration (below 10 Hz) of a bridge, and the harvesting system is integrated with a wireless fatigue crack detection sensor. The uniqueness of the proposed energy harvesting system includes that (1) the resonance frequencies of the proposed energy harvester can be readily tuned to the resonance frequencies of a host structure, (2) an improved energy harvesting efficiency compared to other electromagnetic energy harvesters is achieved in low-frequency and vibration, and (3) high-efficiency energy harvesting circuits for rectification are developed. Furthermore, the developed energy harvesting system is integrated with an on-site wireless sensor deployed on Yeongjong Grand Bridge in South Korea for online fatigue crack detection. To the best knowledge of the authors, this is the very first study where a series of low-frequency vibration energy harvesting, rectification, and battery charging processes are demonstrated under a real field condition. The field test conducted on Yeongjong Grand Bridge, where fatigue cracks have become of a great concern, shows that the proposed energy harvester can generate a peak voltage of 2.27 V and a root mean square voltage of 0.21 V from 0.18-m/s2 root mean square acceleration at 3.05 Hz. It is estimated the proposed energy harvesting system can harness around 67.90 J for 3 weeks and an average power of 37.42 µW. The battery life of the wireless sensor is expected to extend from 1.5 to 2.2 years. The proposed energy harvesting circuits, composed of the AC–DC and boost-up converters, exhibit up to 50% battery charging efficiency when the voltage generated by the proposed energy harvester is 200 mV or higher. The proposed boost-up converter has a 100 times wider input power range than a conventional boost-up converter with a similar efficiency.

scholarly journals The early stage wheel fatigue crack detection using eddy current pulsed thermography

2017 ◽  
Author(s):  
Jianping Peng ◽  
Kang Zhang ◽  
Kai Yang ◽  
Zhu He ◽  
Yu Zhang ◽  
...  
Keyword(s):  
Fatigue Crack ◽  
Eddy Current ◽  
Crack Detection ◽  
Early Stage ◽  
Pulsed Thermography ◽  
Fatigue Crack Detection

scholarly journals Fatigue crack detection in pipes with multiple mode nonlinear guided waves

2018 ◽  
Vol 18 (1) ◽  
pp. 180-192 ◽  
Author(s):  
Ruiqi Guan ◽  
Ye Lu ◽  
Kai Wang ◽  
Zhongqing Su
Keyword(s):  
Fatigue Crack ◽  
Crack Detection ◽  
Guided Waves ◽  
Second Harmonic ◽  
Experimental Testing ◽  
Harmonic Wave ◽  
Guided Wave ◽  
Element Analysis ◽  
Fatigue Crack Detection ◽  
Wave Modes

This study elaborates fundamental differences in fatigue crack detection using nonlinear guided waves between plate and pipe structures and provides an effective approach for analysing nonlinearity in pipe structures. For this purpose, guided wave propagation and interaction with microcrack in a pipe structure, which introduced a contact acoustic nonlinearity, was analysed through a finite element analysis in which the material nonlinearity was also included. To validate the simulation results, experimental testing was performed using piezoelectric transducers to generate guided waves in a specimen with a fatigue crack. Both methods revealed that the second harmonic wave generated by the breathing behaviour of the microcrack in a pipe had multiple wave modes, unlike the plate scenario using nonlinear guided waves. Therefore, a proper index which considered all the generated wave modes due to the microcrack was developed to quantify the nonlinearity, facilitating the identification of microscale damage and further assessment of the severity of the damage in pipe structures.

Laser Lock-In Thermography for Fatigue Crack Detection

2013 ◽  
Vol 558 ◽  
pp. 76-83 ◽  
Author(s):  
Yun Kyu An ◽  
Ji Min Kim ◽  
Hoon Sohn
Keyword(s):  
Fatigue Crack ◽  
Heat Source ◽  
High Power ◽  
Crack Detection ◽  
Laser Source ◽  
Cw Laser ◽  
Laser Heat ◽  
Laser Heat Source ◽  
Fatigue Crack Detection ◽  
Lock In

This study proposes a new nondestructive evaluation methodology named laser lock-in thermography (LLT) for fatigue crack detection. LLT utilizes a high power continuous wave (CW) laser as a heat generation source for lock-in thermography instead of commonly used flash and halogen lamps. The advantages of the proposed LLT method are that (1) the laser heat source can be positioned at an extended distance from a target structure thank to the directionality and low energy loss of the laser source, (2) thermal image degradation due to surrounding temperature disturbances can be minimized because of high temperature gradient generated by the laser source and (3) a large target surface can be inspected using a scanning laser heat source. The developed LLT system is composed of a modulated high power CW laser, galvanometer and infrared camera. Then, a holder exponent-based data processing algorithm is proposed for intuitive damage evaluation. The developed LLT is employed to detect a micro fatigue crack in a metal plate. The test result confirms that 5 μm (or smaller) fatigue crack in a dog-bone shape aluminum plate with a dimension of 400 x 140 x 3 mm3 can be detected.

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