Real-time monitoring of phase maps of digital shearography

Zhu, Lianqing; Wang, Yonghong; Xu, Nan; Wu, Sijin; Dong, Mingli; Yang, Lianxiang

doi:10.1117/1.oe.52.10.101902

Cited by 43 publications

(16 citation statements)

References 32 publications

(29 reference statements)

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“…The phase-shift steps before loading have no effect on the acquisition rate of the system. The fast temporal phase-shift algorithms reduce the number of phase-shift steps after or during loading and can realize dynamic measurement when no phase shift is required [25][26][27].…”

Section: Phase Measurement Technique: Temporal Phase-shift Shearographymentioning

confidence: 99%

Digital Shearography for NDT: Phase Measurement Technique and Recent Developments

et al. 2018

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Composite materials have seen widespread use in the aerospace industry and are becoming increasingly popular in the automotive industry due to their high strength and low weight characteristics. The increasing usage of composite materials has resulted in the need for more effective techniques for nondestructive testing (NDT) of composite structures. Of these techniques, digital shearography is one the most sensitive and accurate methods for NDT. Digital shearography can directly measure strain with high sensitivity when combined with different optical setups, phase-shift techniques, and algorithms. Its simple setup and less sensitivity to environmental disturbances make it particularly well suited for practical NDT applications. This paper provides a review of the phase measurement technique and recent developments in digital shearographic NDT. The introduction of new techniques has expanded the range of digital shearography applications and made it possible to measure larger fields and detect more directional or deeper defects. At the same time, shearography for different materials is also under research, including specular surface materials, metallic materials, etc. Through the discussion of recent developments, the future development trend of digital shearography is analyzed, and the potentials and limitations are demonstrated.

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Section: Phase Measurement Technique: Temporal Phase-shift Shearographymentioning

confidence: 99%

Digital Shearography for NDT: Phase Measurement Technique and Recent Developments

et al. 2018

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“…Phase shift could be temporal and spatial based on different phase shift mechanisms. Temporal phase shift [12,13] is widely used for phase mapping,and can yield relatively clearer results than spatial phase shift. However, temporal phase shift is usually only suitable in static or semidynamic conditions, and not in dynamic conditions such as on a wind tower [14].…”

Section: Introductionmentioning

confidence: 99%

A Compact Laser Shearography System for On-Site Robotic Inspection of Wind Turbine Blades

Tokhi

Zhao

et al. 2021

JAIT

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Shearography is an optical technique in the field of non-destructive evaluation (NDE) of various materials. Its main advantages are that it is non-contact 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 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.

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“…This assumption, used with Eq. (12), results in the following expressions for the three deformation vector components:…”

Section: Calculation Of 3d Deformationsmentioning

confidence: 99%

“…Dynamic deformations are not easily measured, even if the time interval between adjacent phase steps is very short. Though other phase extraction methods, such as spatial phase shift [11] and phase of difference phase shift [12], have been used in DSPI to make dynamic deformation measurement possible, these methods are difficult to use, result in a more complicated system structure, and provide less reliable measurement results. Consequently, these fast phase extraction methods are rarely used in commercial PS-DSPI instruments.…”

Section: Introductionmentioning

confidence: 99%

Universal optical setup for phase-shifting and spatial-carrier digital speckle pattern interferometry

Dong

Fang

et al. 2016

J. Eur. Opt. Soc.-Rapid Publ.

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Background: Digital speckle pattern interferometry (DSPI) is a competitive optical tool for full-field deformation measurement. The two main types of DSPI, phase-shifting DSPI (PS-DSPI) and spatial-carrier DSPI (SC-DSPI), are distinguished by their unique optical setups and methods of phase determination. Each DSPI type has its limited ability in practical applications. Results: We designed a universal optical setup that is suitable for both PS-DSPI and SC-DSPI, with the aim of integrating their respective advantages, including PS-DSPI's precise measurement and SC-DSPI's synchronous measurement, improving DSPI's measuring capacity in engineering. Conclusion: The proposed setup also has several other advantages, including a simple and robust structure, easy adjustment and operation, and versatility of measuring approach.

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Real-time monitoring of phase maps of digital shearography

Cited by 43 publications

References 32 publications

Digital Shearography for NDT: Phase Measurement Technique and Recent Developments

Digital Shearography for NDT: Phase Measurement Technique and Recent Developments

A Compact Laser Shearography System for On-Site Robotic Inspection of Wind Turbine Blades

Universal optical setup for phase-shifting and spatial-carrier digital speckle pattern interferometry

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