scholarly journals Small Displacement Measurement of Crack Opening Using One Pitch Phase Analysis (OPPA) Method

Proceedings ◽  
2018 ◽  
Vol 2 (8) ◽  
pp. 498 ◽  
Author(s):  
Yoshiharu Morimoto ◽  
Akihiro Masaya ◽  
Thomas Yata ◽  
Duy Anh Luong ◽  
Quentin Quarles
Keyword(s):  
Phase Analysis ◽  
Crack Width ◽  
Crack Opening ◽  
Displacement Measurement ◽  
New Method ◽  
Small Displacement

A new method to measure small displacement of crack width.

A Design of High-Accuracy Displacement Measurement Instrument from Principles of Optics

2012 ◽  
Vol 170-173 ◽  
pp. 2924-2928
Author(s):  
Sheng Biao Chen ◽  
Yun Zhi Tan
Keyword(s):  
Measurement Instrument ◽  
High Accuracy ◽  
Mechanical Tests ◽  
Total Reflection ◽  
Displacement Measurement ◽  
New Method ◽  
Water Volume ◽  
Water Drainage ◽  
Accuracy Of Measurement ◽  
Better Than

In order to measure the water drainage volume in soil mechanical tests accurately, it develop a new method which is based on principles of optics. And from both physical and mathematic aspects, it deduces the mathematic relationship between micro change in displacement and the increment projected on screen. The result shows that total reflection condition is better than refraction condition. What’s more, the screen could show the water volume micro variation clearly, so it can improve the accuracy of measurement.

scholarly journals Modeling of Bridging Law for Bundled Aramid Fiber-Reinforced Cementitious Composite and its Adaptability in Crack Width Evaluation

Materials ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 179
Author(s):  
Daiki Sunaga ◽  
Takumi Koba ◽  
Toshiyuki Kanakubo
Keyword(s):  
Fiber Orientation ◽  
Crack Width ◽  
Volume Fraction ◽  
Characteristic Point ◽  
Crack Opening ◽  
Aramid Fiber ◽  
Cementitious Composite ◽  
Fiber Reinforced ◽  
Cross Sectional ◽  
Bridging Law

Tensile performance of fiber-reinforced cementitious composite (FRCC) after first cracking is characterized by fiber-bridging stress–crack width relationships called bridging law. The bridging law can be calculated by an integral calculus of forces carried by individual fibers, considering the fiber orientation. The objective of this study was to propose a simplified model of bridging law for bundled aramid fiber, considering fiber orientation for the practical use. By using the pullout characteristic of bundled aramid fiber obtained in the previous study, the bridging laws were calculated for various cases of fiber orientation. The calculated results were expressed by a bilinear model, and each characteristic point is expressed by the function of fiber-orientation intensity. After that, uniaxial tension tests of steel reinforced aramid-FRCC prism specimens were conducted to obtain the crack-opening behavior and confirm the adaptability of the modeled bridging laws in crack-width evaluation. The experimental parameters are cross-sectional dimensions of specimens and volume fraction of fiber. The test results are compared with the theoretical curves calculated by using the modeled bridging law and show good agreements in each parameter.

A Phase Compensation Technique of Sampling Moiré Method for Accurate Single-Shot Phase Analysis

2011 ◽  
Vol 70 ◽  
pp. 243-248
Author(s):  
Shien Ri ◽  
Takashi Muramatsu ◽  
Masumi Saka
Keyword(s):  
Computer Simulation ◽  
Phase Analysis ◽  
Phase Error ◽  
Linear Interpolation ◽  
Small Displacement ◽  
Single Shot ◽  
Phase Compensation ◽  
Compensation Technique ◽  
Moire Method ◽  
Effective Phase

Recently, a technique for fast and accurate phase analysis called sampling moiré method has been developed for measurement of small-displacement distribution. In this study, a distribution of phase error caused by linear interpolation in case with mismatch between the sampling pitch and the grating pitch is theoretically analyzed. Moreover, a technique for effective phase compensation is proposed to reduce the periodic phase error. The performance of our compensation method is validated by a computer simulation. Phase analysis can be performed more accurately even in the case that the sampling pitch does not match to the grating pitch strictly.

Homodyne detection as an optimal small displacement measurement

2006 ◽  
Author(s):  
V. Delaubert ◽  
N. Treps ◽  
M.T.L. Hsu ◽  
W.P. Bowen ◽  
C. Harb ◽  
...  
Keyword(s):  
Displacement Measurement ◽  
Small Displacement ◽  
Homodyne Detection

A New Method of Preparing Artificial Cores with Certain Cracks for Experiment Study of Elastic Wave Propagation

2011 ◽  
Vol 356-360 ◽  
pp. 2954-2957 ◽  
Author(s):  
Zi Zhen Wang ◽  
Ri He Wang ◽  
Yu Huan Bu ◽  
Xun Shan
Keyword(s):  
Wave Propagation ◽  
Aspect Ratio ◽  
Elastic Wave ◽  
Steel Sheet ◽  
Crack Opening ◽  
Elastic Wave Propagation ◽  
New Method ◽  
Thin Steel Sheet ◽  
Fractured Medium ◽  
Thin Steel

Crack universally existing underground is an important kind of pores. In order to study the elastic wave propagation in fractured medium through experiment, a new method to make artificial core with certain cracks using oil well cement and camphor sheet or thin steel sheet is put forward. Geometric parameters of the crack, such as shape, size and aspect ratio, are approximately equal to that of camphor sheet or thin steel sheet. Using the thin steel sheet to make crack can be more easy and accurate to control the crack angle than using camphor sheet. The crack opening scales at millimeters. The aspect ratio of cracks formed by camphor sheet ranges from 1.4 to 8, and aspect ratio of cracks formed by thin steel sheet ranges from 2.5 to 70. This method is proved simple and feasible by experiment practice, which can provide artificial cores with certain crack for acoustic wave propagation study.

Crack Width Evolution of R/C Structures Subject to Corrosion and Fatigue

2010 ◽  
Vol 452-453 ◽  
pp. 417-420
Author(s):  
Luca Giordano ◽  
Francesco Tondolo
Keyword(s):  
Reinforced Concrete ◽  
Service Life ◽  
Crack Width ◽  
Cyclic Load ◽  
Crack Opening ◽  
Reinforced Concrete Structures ◽  
Chemical Attack ◽  
Experimental Campaign ◽  
Simultaneous Loading ◽  
Concrete Interface

Corrosion modifies the steel-concrete interface in reinforced concrete structures. Moreover in structures subjected to cyclic load, a simultaneous mechanical deterioration due to the load is present. Both phenomena can lead to an evolution of cracks width during the service life. In order to evaluate the crack openings increase, an experimental campaign on reinforced concrete ties subjected to simultaneous loading and corrosion have been realized. Transversal crack opening, initially due to loading and longitudinal corrosion cracks evolution is monitored. Results highlight the differences in terms of corroded and uncorroded specimens, static and cycling test and also different loading amplitude. Finally it can be observed as the growing of the damage is significantly different when a cycling action, combined with a chemical attack is present.

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