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IN-PLANE INSENSITIVE DOUBLE-APERTURE DIGITAL SHEAROGRAPHY FOR SLOPE MEASUREMENT
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作者 顾国庆 王开福 +2 位作者 张成斌 许星 梁智锦 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 2012年第4期367-372,共6页
An improved in-plane insensitive double-aperture digital speckle shearing interferometric technique is proposed to measure the first derivative of out-of-plane displacement (slope). The temporal phase-shifting metho... An improved in-plane insensitive double-aperture digital speckle shearing interferometric technique is proposed to measure the first derivative of out-of-plane displacement (slope). The temporal phase-shifting method is used for the quantitative analysis of fringes. The designed system employs a double-aperture arrange- ment placed in front of the imaging lens. A glass wedge covers one of the two apertures to introduce a laterally shear. The experimental specimen is a circular aluminum plate, clamped along its edge and subjected to both out- of-plane deflection and in-plane rotation. Experimental results show that the fringes obtained from the proposed optical configuration represent pure slope contour distributions, and that the contributions from the in-plane dis- placement components are completely eliminated. Theoretical and experimental results are in good agreement. 展开更多
关键词 digital shearography SLOPE temporal phase-shifting double-aperture
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A Compact Laser Shearography System for On-Site Robotic Inspection of Wind Turbine Blades
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作者 Zhiyao Li Mohammad Osman Tokhi +1 位作者 Zhanfang Zhao Haitao Zheng 《Journal of Artificial Intelligence and Technology》 2021年第3期166-173,共8页
Shearography is an optical technique in the field of nondestructive evaluation(NDE)of various materials.Its main advantages are that it is noncontact type and can cover a large area in a single inspection.As a result,... Shearography is an optical technique in the field of nondestructive evaluation(NDE)of various materials.Its main advantages are that it is noncontact type and can cover a large area in a single inspection.As a result,although it has been widely acknowledged as an effective technique particularly for NDE of composite materials to detect subsurface defects such as delamination,disbond,cracks,and impact damages,the use of shearography for on-site inspection of wind turbine blades(WTBs)has not been reported.This is due to wind causing structural vibration in the WTB.The solution in this paper is to make the shearography sit on the WTB during inspection when the WTB is parked,so that the relative motion between the shearography and the WTB is minimized within the tolerance of the shearography system.The ultimate goal of the solution is to enable a robot-assisted shearography system to inspect the WTB on-site.This paper presents the research work on a new shearography design for integration with a robotic climber for on-site WTB inspection.The approach is tested and evaluated in experimental settings,and a comparative assessment of the approach with other robotic NDE techniques is carried out.The results demonstrate the potential benefits and suitability of the approach for on-site robotic inspection of WTBs. 展开更多
关键词 shearography robotic climber DSSPI ESPI NDE wind turbine blade
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Measurement of absolute three-dimensional displacement gradients using tri-color quad-beam digital shearography
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作者 LI Xuan WU Sijin +1 位作者 TANG Xiaojun LI Weixian 《Optoelectronics Letters》 EI 2023年第8期487-492,共6页
A tri-color quad-beam digital shearography is proposed to achieve the measurement of absolute three-dimensional(3D) displacement gradients.Four laser beams with three different center wavelengths are symmetrically irr... A tri-color quad-beam digital shearography is proposed to achieve the measurement of absolute three-dimensional(3D) displacement gradients.Four laser beams with three different center wavelengths are symmetrically irradiated to the object surface from the upper and lower left and right directions.Four phase maps are then extracted from the two interferograms obtained from two shots.Based on these four phase maps,the absolute 3D displacement gradients are determined.This means of absolute 3D displacement gradient measurement effectively improves the measurement capability of digital shearography and expands its application range. 展开更多
关键词 shearography ABSOLUTE DISPLACEMENT
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A robust phase extraction method for overcoming spectrum overlapping in shearography
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作者 Xiangwei Liu Peizheng Yan Yonghong Wang 《Light(Advanced Manufacturing)》 2023年第1期52-63,共12页
The advantage of spatial phase-shifting shearography is its ability to extract the phase from a single speckle pattern;however,it often faces spectrum overlapping,which seriously affects phase quality.In this paper,we... The advantage of spatial phase-shifting shearography is its ability to extract the phase from a single speckle pattern;however,it often faces spectrum overlapping,which seriously affects phase quality.In this paper,we propose a shearography phase-extraction method based on windowed Fourier ridges,which can effectively extract phase information even in the presence of severe spectrum overlapping.A simple and efficient method was applied to determine the parameters of the windowed Fourier ridges,and a linear variation window was used to match the phase-extraction requirements for different frequency coordinates.A numerical simulation was quantitatively conducted to compare the phase-extraction results of the proposed method with those of the conventional method for various cases,and a shearography system was built with two types of objects to demonstrate the feasibility of the proposed method. 展开更多
关键词 shearography Spatial carrier Phase extraction Spectrum overlapping
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Quality evaluation of rubber-to-metal bonded structures based on shearography 被引量:4
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作者 LIU Bin GUO XingMing +1 位作者 QI GongJin ZHANG DongSheng 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS CSCD 2015年第7期49-56,共8页
The quality of bonding is often a concern in rubber-to-metal bonded parts with regard to the integrity and stability of the structure. In this study, shearography has been used to detect the out-of-plane deformation o... The quality of bonding is often a concern in rubber-to-metal bonded parts with regard to the integrity and stability of the structure. In this study, shearography has been used to detect the out-of-plane deformation of the defects caused by thermal and vacuum stresses. A sample of the vulcanized styrene-butadiene rubber bonded to steel with known artificial voids was prepared and during bonding process a region was glued with thick adhesives. The rubber surface of the sample was inspected in thermal radiation and vacuum modes respectively with a self-designed shearography device. Meanwhile, a numerical simulation was conducted to predict the out-of-plane deformation of the rubber surface in these two stress modes. Results from the numerical simulation and the experiments indicated that the debonding defects could be inspected in both loading modes. In the thermal radiation mode the region with thick adhesives could be identified successfully. This study provides a guideline for quality control of rubber-to-metal structures using an optical method. 展开更多
关键词 shearography optical mechanics DEBONDING
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Shearography and its applications-a chronological review 被引量:2
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作者 Rajpal Sirohi 《Light(Advanced Manufacturing)》 2022年第1期1-30,共30页
This paper presents the activities in the field of shearography in chronological order and highlights the great potential of this holographic measurement technology.After a brief introduction,the basic theory of shear... This paper presents the activities in the field of shearography in chronological order and highlights the great potential of this holographic measurement technology.After a brief introduction,the basic theory of shearography is presented.Shear devices,phase-shift arrangements,and multiplexed shearography systems are described.Finally,the application areas where shearography has been accepted and successfully used as a tool are presented. 展开更多
关键词 Electronic speckle pattern interferometry shearography Non-destructive testing
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Influence of welding parameters on fracture toughness and fatigue crack growth rate in friction stir welded nugget of 2024-T351 aluminum alloy joints 被引量:1
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作者 Danial GHAHREMANI MOGHADAM Khalil FARHANGDOOST 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2016年第10期2567-2585,共19页
Friction stir welding (FSW) was performed on 2024-T351 aluminum alloy plates. Metallographic analysis, Vickers microhardness and XRD tests were conducted to determine the properties of the welded zone. FE simulatio... Friction stir welding (FSW) was performed on 2024-T351 aluminum alloy plates. Metallographic analysis, Vickers microhardness and XRD tests were conducted to determine the properties of the welded zone. FE simulation of the FSW process was implemented for the different welding conditions to extract the residual stress and stress intensity factor (SIF). Fracture and fatigue behaviors of the welds which have the initial crack in the nugget zone and the crack orientation along the welding direction, were studied based on standard test methods. Fracture behavior of the welds was also evaluated by shearography method. The results showed that the tool rotational and traverse speeds affect the fracture toughness and fatigue crack growth rate. FSW provides 18%-49% reductions in maximum fracture load and fracture toughness. A slight diminution in fracture toughness of the joints was observed for lower traverse speed of the tool, and at higher traverse or rotational speeds, increasing the probability of defects may contribute to low fracture toughness. Fatigue crack propagation rate of all welds was slower than that of the base metal for low values of stress intensity factor range ΔK (ΔK〈13 MPa·m^1/2), but is much faster for high values of ΔK. 展开更多
关键词 aluminum alloy friction stir welding fracture toughness shearography fatigue crack propagation rate
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New multiplexed system for synchronous measurement of out-of-plane deformation and two orthogonal slopes
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作者 Yonghong Wang Xiao Zhang +3 位作者 Qihan Zhao Yanfeng Yao Peizheng Yan Biao Wang 《Chinese Physics B》 SCIE EI CAS CSCD 2022年第3期259-264,共6页
We propose a novel system for synchronous measurement of out-of-plane deformation and two orthogonal slopes using a single camera. The linearly polarized reference beam introduced by an optical fiber interferes with t... We propose a novel system for synchronous measurement of out-of-plane deformation and two orthogonal slopes using a single camera. The linearly polarized reference beam introduced by an optical fiber interferes with the unpolarized object beam to measure the out-of-plane deformation. A modified Mach–Zehnder interferometer is used to measure the two orthogonal slopes of the out-of-plane deformation. One of the object beams of the Mach–Zehnder interferometer is an unpolarized beam, and the other object beam is split into two orthogonal linearly polarized object beams by a polarizing prism. The two beams are orthogonally polarized. Hence, they will not interfere with each other. The two polarized beams respectively interfere with the unpolarized beam to simultaneously measure the two orthogonal slopes of the out-of-plane deformation. In addition, the imaging lens and apertures are respectively placed in three optical paths to independently control the carrier frequencies and shearing amounts. The effectiveness of this method can be proved by measuring two pressure-loaded circular plates. 展开更多
关键词 digital speckle pattern interferometry digital shearography simultaneous measurement of displacement and two orthogonal slopes
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Successes and challenges in non-destructive testing of aircraft composite structures 被引量:31
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作者 Hossein TOWSYFYAN Ander BIGURI +1 位作者 Richard BOARDMAN Thomas BLUMENSATH 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2020年第3期771-791,共21页
Composite materials are increasingly used in the aerospace industry.To fully realise the weight saving potential along with superior mechanical properties that composites offer in safety critical applications,reliable... Composite materials are increasingly used in the aerospace industry.To fully realise the weight saving potential along with superior mechanical properties that composites offer in safety critical applications,reliable Non-Destructive Testing(NDT)methods are required to prevent catastrophic failures.This paper will review the state of the art in the field and point to highlight the success and challenges that different NDT methods are faced to evaluate the integrity of critical aerospace composites.The focus will be on advanced certificated NDT methods for damage detection and characterization in composite laminates for use in the aircraft primary and secondary structures. 展开更多
关键词 Acoustic emission Aircraft composite structures Eddy Current Testing Infra-Red Thermography Laser shearography Non-Destructive Testing(NDT) Ultrasonic testing X-ray radiography and tomography
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