Displacement measurements in structural elements by optical techniques

González-Peña, Rolando J.; Anda, Rosa Marı́a Cibrián-Ortiz de; Pino-Velazquez, Angel J; Cruz, José Anderson Santos; González-Jorge, Yhoama

doi:10.1016/s0143-8166(00)00088-9

Cited by 10 publications

(4 citation statements)

References 11 publications

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“…When the specimen surface status is changed due to a mechanical or thermal stress, if the displacement of a point on the object is less than the speckle size [9], the intensity distribution can be written as formula (2) shown below ( , ) ( , ) ( , ) cos( )…”

Section: The Principle Of Phase-shifting Methodsmentioning

confidence: 99%

“…Electronic speckle pattern interferometry (ESPI) is a method for measuring the deformation [1] or displacement [2] of an object surface in which at least two interferograms (speckle patterns) are recorded while the object is deformed. Since noise will affect significantly the quality of experimental measurements as well as it will determine whether the entire measurement process can be carried out automatically or not, the availability of spatial filtering for the interferometric images becomes a primary problem.…”

Section: Introductionmentioning

confidence: 99%

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Phase Algorithm Integrating Direct-Correlation and Four-Step Phase-Shifting for Electronic Speckle Pattern Interferometry

Li²,

Zhou³

2013

AMM

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A phase-shifting algorithm, called a (4,4) algorithm, which takes four phase-shifting interferograms before a specimen is deformed and four interferograms after a specimen is deformed, is presented first. This method is most widely used for phase extraction. Its drawback limited it to be used in dynamic measurements. Also shown is an algorithm called a (4,1) algorithm that takes four phase-shifting interferograms before a specimen is deformed and one interferogram after a specimen is deformed. Because a high-speed camera can be used to record the dynamic interferogram of the specimen, this algorithm has the potential to retain the phase-shifting capability for ESPI in dynamic measurements. The quality of the phase map obtained using (4,1) algorithm is quite lower compared to using (4,4) algorithm. In order to obtain high-quality phase map in dynamic measurements, a direct-correlation algorithm was integrated with the (4,1) algorithm to form DC-(4,1) algorithm which is shown to improve significantly the quality of the phase maps. The theoretical and experimental aspects of this newly developed technique, which can extend ESPI to areas such as high-speed dynamic measurements, are examined in detail.

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Section: The Principle Of Phase-shifting Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Phase Algorithm Integrating Direct-Correlation and Four-Step Phase-Shifting for Electronic Speckle Pattern Interferometry

Li²,

Zhou³

2013

AMM

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“…Tripi et al 20 used the same method to measure the surface deformations and strains of cracked concrete prisms with externally bonded FRP sheets. Gonzalez-Pena et al 21 used the speckle photography to observe the displacement field of two shear walls with different boundary conditions. Cao et al 22 established a bond-slip law for FRP composites bonded to concrete, and this is based on experimental data obtained using the ESPI.…”

Section: Introductionmentioning

confidence: 99%

Experimental study on bond behavior between SMPM and concrete using dual-beam speckle interferometry

Guo

Song

Chen

et al. 2011

Journal of Reinforced Plastics and Composites

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Steel stranded wire mesh and polymer mortar (SMPM) is a novel technique for structural strengthening. To study the still unknown bond behavior between SMPM composites and concrete, the dual-beam speckle interferometry with four-step phase-shifting is used in double-shear tests. Displacements of SMPM composites are obtained by unwrapping the phase pattern due to deformation, and derivation of the displacements results in the strains. Twenty-five specimens were tested with different strengthening parameters to investigate their influences on the bond behavior. It is found that the measured strain distributions are different from those in fiber-reinforced polymer (FRP) sheets, but are similar to the bond strains existed in the FRP-concrete interface. Locations of transversal wires have a significant influence on the strain distributions and the debonding loads. The maximum displacements before brittle debonding occurs are about an order of magnitude smaller than those of FRP composites. According to the test data, a bond strength model is developed to predict the debonding loads, in which a number of factors, such as interfacial roughness, concrete strength, and locations of transversal wires, etc., are taken into account. A three segment stress—displacement relationship is proposed to describe the debonding behavior of SMPM composites.

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“…A major advantage of this method is the relative simplicity of the experimental set-up [2][3][4][5]. It has been applied successfully to study structural elements [6,7] and to measure deformation in buildings in situ [8,9]. Some optical tests, however, due to experimental limitations, cannot be applied directly to real structures because of the large dimensions sometimes involved; consequently the use of reduced scale models becomes necessary.…”

Section: Introductionmentioning

confidence: 99%

Displacements measurement in a building model using the speckle photography technique

González-Peña

Anda

Pino-Velazquez

et al. 2005

Engineering Structures

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Displacement measurements in structural elements by optical techniques

Cited by 10 publications

References 11 publications

Phase Algorithm Integrating Direct-Correlation and Four-Step Phase-Shifting for Electronic Speckle Pattern Interferometry

Phase Algorithm Integrating Direct-Correlation and Four-Step Phase-Shifting for Electronic Speckle Pattern Interferometry

Experimental study on bond behavior between SMPM and concrete using dual-beam speckle interferometry

Displacements measurement in a building model using the speckle photography technique

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