Multiplication sampling moiré method for full-field deformation measurement of composite materials

2021 ◽  
Author(s):  
Qinghua Wang ◽  
Shien Ri ◽  
M.J. Mohammad Fikry ◽  
Shinji Ogihara
Keyword(s):  
Composite Materials ◽  
Deformation Measurement ◽  
Full Field ◽  
Moire Method

Study on Mechanical Properties of the Composite Materials Film by Speckle Projection Method

2012 ◽  
Vol 496 ◽  
pp. 281-284
Author(s):  
Wen Wen Liu ◽  
Zhi Wang ◽  
Yun Hai Du ◽  
Xian Zhong Xu ◽  
Da Quan Liu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Composite Material ◽  
Composite Materials ◽  
Projection Method ◽  
Dynamic Deformation ◽  
Calibration Method ◽  
Deformation Measurement ◽  
Lens Distortion

An improved accurate speckle projection method is used for study the mechanical properties of the composite material film in the paper. A system for deformation measurement is developed with the telecentric lenses, in which such conventional lens’ disadvantages such as lens distortion and perspective error will be diminished. Experiments are performed to validate the availability and reliability of the calibration method. The system can also be used to measure the dynamic deformation and then results are also given.

scholarly journals Computer-automated shadow moiré method and applications for 3D surface profiling

2021 ◽  
Author(s):  
Rui Zhao
Keyword(s):  
Least Square ◽  
Automated System ◽  
Image Subtraction ◽  
Full Field ◽  
Surface Profiling ◽  
Shadow Moire ◽  
Shadow Moiré ◽  
3D Surface ◽  
Measurement Resolution ◽  
Moire Method

Among numerous methods for 3D surface profiling, classic shadow moiré method has been kept as the most popular one due to its full-field feature and low cost. This thesis focuses on a computer-vision shadow moiré method with a scope to improve the measurement resolution, accuracy and efficiency. The computer automation is basically realized through the introduction of a phase-shifting technique that is incorporated with a new multi-grid least-square unwrapping algorithm. The method is enhanced by implementing a few additional image processing techniques. These techniques, when implemented, result in improved measurement accuracy and enable easy applications to irregularly shaped surfaces. The study also proposes a new, automated system calibration approach that is based on a real-time image subtraction. A data normalization process is studied to resolve possible confusions in the presentation of the original data. The verification test results show that the modified shadow moiré technique has achieved the initial goal, in that the measurement resolution now reaches a few percentage of the fringe sensititivity.

scholarly journals Vision-based Deformation Measurement for Pile-soil Testing

2019 ◽  
Vol 275 ◽  
pp. 03009
Author(s):  
Kun Zhou ◽  
Linhua Chen ◽  
Shanshan Yu
Keyword(s):  
Measurement Method ◽  
Optical Measurement ◽  
High Sensitivity ◽  
Steel Tube ◽  
Image Features ◽  
Deformation Measurement ◽  
Measurement Technology ◽  
Full Field ◽  
Progressive Development ◽  
Point Tracking

Image measurement technology has been widely used in monitoring the deformation of the soil field around the pile with its advantages of no damage, no contact, full-field measurement, no added quality and high sensitivity. But there are few researches on image-based bearing deformation measurement of the pile. Through an indoor pile-soil semi-model test, the rigid body displacement and load-bearing deformation of a new type of prefabricated steel tube pile foundation under horizontal load was measured based on image features. In this study, the concept of optical extensometer is first applied to the measurement of local average strain of a non-uniform deformed structure. Based on an improved feature point tracking algorithm SURF-BRISK, non-contact measurement of tiny strain of pile body is realized. In addition, based on DIC technology, this study also obtained the progressive development of displacement field of soil around pile. The above work fully reflects the non-contact convenience and full-field richness of the optical measurement method compared with the traditional measurement method.

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