Chen Ciang Chia - Academia.edu (original) (raw)
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Papers by Chen Ciang Chia
An ultrasonic propagation imaging (UPI) system consisted of a Q-switched Nd-YAG pulsed laser and ... more An ultrasonic propagation imaging (UPI) system consisted of a Q-switched Nd-YAG pulsed laser and a galvanometer laser mirror scanner was developed. The system which requires neither reference data nor fixed focal length could be used for health monitoring of curved structures. If combined with a fiber acoustic wave PZT (FAWPZT) sensor, it could be used to inspect hot target structures that present formidable challenges to the usage of contact piezoelectric transducers mainly due to the operating temperature limitation of transducers and debonding problem due to the mismatch of coefficient of thermal expansion between the target, transducer and bonding material. The inspection of a stainless steel plate with a curvature radius of about 4 m, having 2mm×1mm open-crack was demonstrated at 150°C using a FAWPZT sensor welded on the plate. Highly-curved surfaces scanning capability and adaptivity of the system for large laser incident angle up to 70° was demonstrated on a stainless steel cylinder with 2mm×1mm open-crack. The imaging results were presented in ultrasonic propagation movie which was a moving wavefield emerged from an installed ultrasonic sensor. Damages were localized by the scattering wavefields. The result images enabled easy detection and interpretation of structural defects as anomalies during ultrasonic wave propagation.
Advanced Materials Research, 2010
Abstract Non-destructive evaluation (NDE) and structural health management (SHM) with the ability... more Abstract Non-destructive evaluation (NDE) and structural health management (SHM) with the ability to evaluate the severity of a damage are important to ensure the reliability of a structure. We propose a local non-destructive evaluation (NDE) system based on ...
Optics and Laser Technology, 2012
Laser ultrasonic wave propagation imaging methods have great potential for integrated structural ... more Laser ultrasonic wave propagation imaging methods have great potential for integrated structural health management and non-destructive evaluation. However, application of these techniques to complex structures in the field is difficult because they give rise to complicated wave propagation patterns. We developed an anomalous wave propagation imaging method with adjacent wave subtraction using laser ultrasonic scanning to solve this problem. The proposed method is suitable for non-destructive evaluation of complex structures because it highlights the propagation of anomalous waves related to structural discontinuities, and suppresses complex incident waves without the need of pre-stored reference data. In this study, the method was applied to a real composite wing subjected to bending and impact tests. The method enhanced the visibility of the anomalous waves related to damages such as stringer tip debonding, skin-spar debonding, and invisible impact damage. Based on these anomalous waves, variable time window amplitude mapping was performed to show the damage location, size, and shape resemble to the actual damage. Comparisons showed that the methods performed better than the ultrasonic A-scan in terms of damage detection and sizing accuracy. The presence of structural elements such as spars, stringers, ribs, and surface-mounted PZT elements did not adversely affect the inspection. The proposed wing test setup with a built-in ultrasonic propagation imaging system for automatic NDE could be easily expanded throughout a hanger for maintenance inspection.
Optics and Lasers in Engineering, 2011
Wind turbine blade failure is the most prominent and common type of damage occurring in operating... more Wind turbine blade failure is the most prominent and common type of damage occurring in operating wind turbine systems. Conventional nondestructive testing systems are not available for in situ wind turbine blades. We propose a portable long distance ultrasonic propagation imaging (LUPI) system that uses a laser beam targeting and scanning system to excite, from a long distance, acoustic emission sensors installed in the blade. An examination of the beam collimation effect using geometric parameters of a commercial 2 MW wind turbine provided Lamb wave amplitude increases of 41.5 and 23.1 dB at a distance of 40 m for symmetrical and asymmetrical modes, respectively, in a 2 mm-thick stainless steel plate. With this improvement in signal-to-noise ratio, a feasibility study of damage detection was conducted with a 5 mm-thick composite leading edge specimen. To develop a reliable damage evaluation system, the excitation/sensing technology and the associated damage visualization algorithm are equally important. Hence, our results provide a new platform based on anomalous wave propagation imaging (AWPI) methods with adjacent wave subtraction, reference wave subtraction, reference image subtraction, and the variable time window amplitude mapping method. The advantages and disadvantages of AWPI algorithms are reported in terms of reference data requirements, signal-to-noise ratios, and damage evaluation accuracy. The compactness and portability of the proposed UPI system are also important for in-field applications at wind farms.► Portable long distance laser ultrasonic propagation imaging (LUPI) system. ► A new anomalous wave propagation imaging (AWPI) methods based platform was developed. ► It provided enhancement and accuracy in damage visibility, localization and size. ► The system feasibility was verified considering a 2 MW commercial wind turbine system. ► LUPI system shows applicability for in-field long distance wind turbine applications.
Advanced Materials Research, 2010
Optics and Lasers in Engineering, 2011
A wavelet-transformed ultrasonic propagation imaging method capable of ultrasonic propagation ima... more A wavelet-transformed ultrasonic propagation imaging method capable of ultrasonic propagation imaging in the frequency domain was developed and applied as a new structural damage or flaw visualization algorithm. Since the wavelet-transformed ultrasonic propagation imaging method has strong frequency selectivity, it can visualize the propagation of ultrasonic waves of a specific frequency (for example, to isolate ultrasonic mode of interest and a damage-related ultrasonic wave). The strong frequency selectivity of the wavelet-transformed ultrasonic propagation imaging method was demonstrated, isolating only the zeroth-order asymmetrical mode of the fundamental Lamb wave modes in an anisotropic carbon fiber-reinforced plastic plate with a thickness of 5 mm. The wavelet-transformed ultrasonic propagation imaging method can also convert a complex time domain multiple wavefield into a simple frequency domain single wavefield. This feature enables easy interpretation of the results, and facilitates the precise evaluation of the location and size of structural damage or flaws. We demonstrated this capability by detecting a disbond in a sandwich structure made of Al-alloy skins and a foam core. A disbond with a diameter of 20 mm, which is representative of a common manufacturing flaw, was successfully detected, localized, and evaluated. Since a method to determine the allowable maximum pulse repetition frequency depending on target materials and structures was found by investigating the residual wave caused from the previous laser impinging, our laser ultrasonic system can scan rapidly the target with an optimal pulse repetition rate. In addition, the proposed wavelet-transformed ultrasonic propagation imaging method can visualize damage or flaw without the need for reference data from the intact state of the structure. Hence, we propose the wavelet-transformed ultrasonic propagation imaging approach for automatic inspection of in-service engineering structures, or in-process quality inspection in manufacturing.
Nuclear Engineering and Design, 2010
Hundreds of kilometers of pipeline, especially the elbows and welded joints in nuclear power plan... more Hundreds of kilometers of pipeline, especially the elbows and welded joints in nuclear power plants (NPPs), are susceptible to aging and other types of damage. Therefore, the condition of a piping system requires regular inspection. We propose an automatic damage visualization technique using a laser ultrasonic scanning system and an ultrasonic wave propagation imaging (UWPI) method for the regular inspection process. Ultrasonic wave propagation movies (UWPMs) in thick and complex NPP pipes could be successfully visualized in a straight pipe with a crack, a welded pipe with multiple open and inner cracks at the welds, and an elbow pipe with wall thinning. A UWPM with ultrasonic time information could enable the discrimination of damage-induced wavefields from the wavefield not related to damage by providing the appearance time, source location, wavefront curvature, and propagation direction of the damage-induced wavefield. For the specimens tested, a 1 mm long crack in a 9 mm thick pipe could be localized regardless of the relative orientation of a sensor to the crack direction; 4 mm long 1.5 mm deep inner crack in a 4 mm thick welding bead could be detected despite the presence of the welding bead; wall thinning with gradual property variations could also be detected. In addition, since this method did not require laser focusing or reference data from the undamaged condition, and allows a large laser beam incident angle, it was very advantageous for the automatic scanning of the curved pipe surfaces. This study demonstrated that the proposed laser ultrasonic system equipped with the UWPI method is a useful inspection tool for NPP piping system management.
Measurement Science & Technology, 2009
The direct attachment of piezoelectric transducers onto hot targets raises formidable challenges ... more The direct attachment of piezoelectric transducers onto hot targets raises formidable challenges as piezoelectric transducers lose their piezoelectric characteristics at elevated temperatures or debond due to thermal expansion coefficient mismatches. We developed a welded fibre acoustic-wave PZT (FAWPZT) sensor to alleviate these temperature limitations. One end of the FAWPZT sensor, made from a stainless steel fibre, was welded onto a
Measurement Science & Technology, 2008
An ultrasonic propagation imaging (UPI) system consisted of a Q-switched Nd-YAG pulsed laser and ... more An ultrasonic propagation imaging (UPI) system consisted of a Q-switched Nd-YAG pulsed laser and a galvanometer laser mirror scanner was developed. The system which requires neither reference data nor fixed focal length could be used for health monitoring of curved structures. If combined with a fiber acoustic wave PZT (FAWPZT) sensor, it could be used to inspect hot target structures that present formidable challenges to the usage of contact piezoelectric transducers mainly due to the operating temperature limitation of transducers and debonding problem due to the mismatch of coefficient of thermal expansion between the target, transducer and bonding material. The inspection of a stainless steel plate with a curvature radius of about 4 m, having 2mm×1mm open-crack was demonstrated at 150°C using a FAWPZT sensor welded on the plate. Highly-curved surfaces scanning capability and adaptivity of the system for large laser incident angle up to 70° was demonstrated on a stainless steel cylinder with 2mm×1mm open-crack. The imaging results were presented in ultrasonic propagation movie which was a moving wavefield emerged from an installed ultrasonic sensor. Damages were localized by the scattering wavefields. The result images enabled easy detection and interpretation of structural defects as anomalies during ultrasonic wave propagation.
Advanced Materials Research, 2010
Abstract Non-destructive evaluation (NDE) and structural health management (SHM) with the ability... more Abstract Non-destructive evaluation (NDE) and structural health management (SHM) with the ability to evaluate the severity of a damage are important to ensure the reliability of a structure. We propose a local non-destructive evaluation (NDE) system based on ...
Optics and Laser Technology, 2012
Laser ultrasonic wave propagation imaging methods have great potential for integrated structural ... more Laser ultrasonic wave propagation imaging methods have great potential for integrated structural health management and non-destructive evaluation. However, application of these techniques to complex structures in the field is difficult because they give rise to complicated wave propagation patterns. We developed an anomalous wave propagation imaging method with adjacent wave subtraction using laser ultrasonic scanning to solve this problem. The proposed method is suitable for non-destructive evaluation of complex structures because it highlights the propagation of anomalous waves related to structural discontinuities, and suppresses complex incident waves without the need of pre-stored reference data. In this study, the method was applied to a real composite wing subjected to bending and impact tests. The method enhanced the visibility of the anomalous waves related to damages such as stringer tip debonding, skin-spar debonding, and invisible impact damage. Based on these anomalous waves, variable time window amplitude mapping was performed to show the damage location, size, and shape resemble to the actual damage. Comparisons showed that the methods performed better than the ultrasonic A-scan in terms of damage detection and sizing accuracy. The presence of structural elements such as spars, stringers, ribs, and surface-mounted PZT elements did not adversely affect the inspection. The proposed wing test setup with a built-in ultrasonic propagation imaging system for automatic NDE could be easily expanded throughout a hanger for maintenance inspection.
Optics and Lasers in Engineering, 2011
Wind turbine blade failure is the most prominent and common type of damage occurring in operating... more Wind turbine blade failure is the most prominent and common type of damage occurring in operating wind turbine systems. Conventional nondestructive testing systems are not available for in situ wind turbine blades. We propose a portable long distance ultrasonic propagation imaging (LUPI) system that uses a laser beam targeting and scanning system to excite, from a long distance, acoustic emission sensors installed in the blade. An examination of the beam collimation effect using geometric parameters of a commercial 2 MW wind turbine provided Lamb wave amplitude increases of 41.5 and 23.1 dB at a distance of 40 m for symmetrical and asymmetrical modes, respectively, in a 2 mm-thick stainless steel plate. With this improvement in signal-to-noise ratio, a feasibility study of damage detection was conducted with a 5 mm-thick composite leading edge specimen. To develop a reliable damage evaluation system, the excitation/sensing technology and the associated damage visualization algorithm are equally important. Hence, our results provide a new platform based on anomalous wave propagation imaging (AWPI) methods with adjacent wave subtraction, reference wave subtraction, reference image subtraction, and the variable time window amplitude mapping method. The advantages and disadvantages of AWPI algorithms are reported in terms of reference data requirements, signal-to-noise ratios, and damage evaluation accuracy. The compactness and portability of the proposed UPI system are also important for in-field applications at wind farms.► Portable long distance laser ultrasonic propagation imaging (LUPI) system. ► A new anomalous wave propagation imaging (AWPI) methods based platform was developed. ► It provided enhancement and accuracy in damage visibility, localization and size. ► The system feasibility was verified considering a 2 MW commercial wind turbine system. ► LUPI system shows applicability for in-field long distance wind turbine applications.
Advanced Materials Research, 2010
Optics and Lasers in Engineering, 2011
A wavelet-transformed ultrasonic propagation imaging method capable of ultrasonic propagation ima... more A wavelet-transformed ultrasonic propagation imaging method capable of ultrasonic propagation imaging in the frequency domain was developed and applied as a new structural damage or flaw visualization algorithm. Since the wavelet-transformed ultrasonic propagation imaging method has strong frequency selectivity, it can visualize the propagation of ultrasonic waves of a specific frequency (for example, to isolate ultrasonic mode of interest and a damage-related ultrasonic wave). The strong frequency selectivity of the wavelet-transformed ultrasonic propagation imaging method was demonstrated, isolating only the zeroth-order asymmetrical mode of the fundamental Lamb wave modes in an anisotropic carbon fiber-reinforced plastic plate with a thickness of 5 mm. The wavelet-transformed ultrasonic propagation imaging method can also convert a complex time domain multiple wavefield into a simple frequency domain single wavefield. This feature enables easy interpretation of the results, and facilitates the precise evaluation of the location and size of structural damage or flaws. We demonstrated this capability by detecting a disbond in a sandwich structure made of Al-alloy skins and a foam core. A disbond with a diameter of 20 mm, which is representative of a common manufacturing flaw, was successfully detected, localized, and evaluated. Since a method to determine the allowable maximum pulse repetition frequency depending on target materials and structures was found by investigating the residual wave caused from the previous laser impinging, our laser ultrasonic system can scan rapidly the target with an optimal pulse repetition rate. In addition, the proposed wavelet-transformed ultrasonic propagation imaging method can visualize damage or flaw without the need for reference data from the intact state of the structure. Hence, we propose the wavelet-transformed ultrasonic propagation imaging approach for automatic inspection of in-service engineering structures, or in-process quality inspection in manufacturing.
Nuclear Engineering and Design, 2010
Hundreds of kilometers of pipeline, especially the elbows and welded joints in nuclear power plan... more Hundreds of kilometers of pipeline, especially the elbows and welded joints in nuclear power plants (NPPs), are susceptible to aging and other types of damage. Therefore, the condition of a piping system requires regular inspection. We propose an automatic damage visualization technique using a laser ultrasonic scanning system and an ultrasonic wave propagation imaging (UWPI) method for the regular inspection process. Ultrasonic wave propagation movies (UWPMs) in thick and complex NPP pipes could be successfully visualized in a straight pipe with a crack, a welded pipe with multiple open and inner cracks at the welds, and an elbow pipe with wall thinning. A UWPM with ultrasonic time information could enable the discrimination of damage-induced wavefields from the wavefield not related to damage by providing the appearance time, source location, wavefront curvature, and propagation direction of the damage-induced wavefield. For the specimens tested, a 1 mm long crack in a 9 mm thick pipe could be localized regardless of the relative orientation of a sensor to the crack direction; 4 mm long 1.5 mm deep inner crack in a 4 mm thick welding bead could be detected despite the presence of the welding bead; wall thinning with gradual property variations could also be detected. In addition, since this method did not require laser focusing or reference data from the undamaged condition, and allows a large laser beam incident angle, it was very advantageous for the automatic scanning of the curved pipe surfaces. This study demonstrated that the proposed laser ultrasonic system equipped with the UWPI method is a useful inspection tool for NPP piping system management.
Measurement Science & Technology, 2009
The direct attachment of piezoelectric transducers onto hot targets raises formidable challenges ... more The direct attachment of piezoelectric transducers onto hot targets raises formidable challenges as piezoelectric transducers lose their piezoelectric characteristics at elevated temperatures or debond due to thermal expansion coefficient mismatches. We developed a welded fibre acoustic-wave PZT (FAWPZT) sensor to alleviate these temperature limitations. One end of the FAWPZT sensor, made from a stainless steel fibre, was welded onto a
Measurement Science & Technology, 2008