Guided wave-based bend detection in pipes using in-plane shear piezoelectric wafers

2020 ◽  
Vol 116 ◽  
pp. 102312
Author(s):  
Xin Zhang ◽  
Wensong Zhou ◽  
Hui Li ◽  
Yuxiang Zhang
Keyword(s):  
Guided Wave ◽  
Plane Shear ◽  
Piezoelectric Wafers

scholarly journals Guided Wave-Based Monitoring of Evolution of Fatigue Damage in Glass Fiber/Epoxy Composites

2019 ◽  
Vol 9 (7) ◽  
pp. 1394 ◽  
Author(s):  
Gang Yan ◽  
Xiang Lu ◽  
Jianfei Tang
Keyword(s):  
Glass Fiber ◽  
Fatigue Damage ◽  
Composite Structures ◽  
Guided Waves ◽  
Wavelet Packet ◽  
Guided Wave ◽  
Longitudinal Stiffness ◽  
Potential Applicability ◽  
Characteristic Features ◽  
Piezoelectric Wafers

This paper presents an experimental study on detecting and monitoring of evolution of fatigue damage in composites under cyclic loads by using guided waves. Composite specimens fabricated by glass fiber/epoxy laminates and surface mounted with piezoelectric wafers are fatigued under tension–tension loads. A laser extensometer is used to obtain the degradation of longitudinal stiffness of the specimens under fatigue states to reflect the accumulation of internal fatigue damage. Meanwhile, at different fatigue cycles, one wafer acts as actuator to excite diagnostic guided waves, and the other acts as sensor to receive corresponding response waves. These guided wave signals are then processed by wavelet packet transform to extract characteristic features of energies in multiple frequency bands. A statistical multivariate outlier analysis is then performed to determine the existence of fatigue damage and to characterize their evolution using Mahalanobis squared distance. Experimental results have demonstrated the potential applicability and effectiveness of guided waves for continuous monitoring of fatigue damage in composite structures.

Temperature Influence Compensation for Lamb Wave Damage Detection

2011 ◽  
Vol 105-107 ◽  
pp. 621-625
Author(s):  
Wen Zhong Qu ◽  
D.J. Inman
Keyword(s):  
Wave Propagation ◽  
Lamb Wave ◽  
Elevated Temperatures ◽  
Lamb Waves ◽  
Guided Wave ◽  
Diagnostic Tools ◽  
Temperature Influence ◽  
Compensation Approach ◽  
Lamb Wave Propagation ◽  
Piezoelectric Wafers

Among structural health monitoring (SHM) techniques, Lamb waves is frequently used as diagnostic tools to detect damage in plate-like structures. Temperature variation can cause significant changes in guided-wave propagation and transduction for SHM. In this paper, controlled experiments examine changes in Lamb wave propagation and transduction using PZT-5A piezoelectric wafers under quasi-statically varying temperature (from 5°C to 60°C). The baseline selection method and baseline signal stretch method are used to compensate the temperature influence on Lamb wave propagation. The results of the experiments demonstrate the effectiveness of the temperature compensation approach and the simulated damage on the plate can be detected effectively under elevated temperatures environment.

A compact guided-wave EMAT with pulsed electromagnet for ferromagnetic tube inspection

2020 ◽  
Vol 64 (1-4) ◽  
pp. 951-958
Author(s):  
Tianhao Liu ◽  
Yu Jin ◽  
Cuixiang Pei ◽  
Jie Han ◽  
Zhenmao Chen
Keyword(s):  
Power Plants ◽  
Signal To Noise Ratio ◽  
Small Diameter ◽  
Performance Testing ◽  
Guided Wave ◽  
High Signal ◽  
Receiver Coil ◽  
Signal To Noise ◽  
Corrosion Defects

Small-diameter tubes that are widely used in petroleum industries and power plants experience corrosion during long-term services. In this paper, a compact inserted guided-wave EMAT with a pulsed electromagnet is proposed for small-diameter tube inspection. The proposed transducer is noncontact, compact with high signal-to-noise ratio and unattractive to ferromagnetic tubes. The proposed EMAT is designed with coils-only configuration, which consists of a pulsed electromagnet and a meander pulser/receiver coil. Both the numerical simulation and experimental results validate its feasibility on generating and receiving L(0,2) mode guided wave. The parameters for driving the proposed EMAT are optimized by performance testing. Finally, feasibility on quantification evaluation for corrosion defects was verified by experiments.

Particle-Based Modelling of In-Plane Shear in Textiles

2018 ◽  
Vol 12 (2) ◽  
pp. 142
Author(s):  
Reza Samadi ◽  
Francois Robitaille
Keyword(s):  
Plane Shear
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