Measurement of out-of-plane deformation by combination of speckle photography and speckle shearing interferometry

Barrientos, Bernardino; Martı́nez-Celorio, R.A.; López, Luis Martı́; Dirckx, J.J.J.; Cywiak, Moisés

doi:10.1078/0030-4026-00362

Cited by 16 publications

(5 citation statements)

References 13 publications

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“…In situ observations of inelastic strain produced during loading at atmospheric pressure may be made using image processing to analyze the deformation of material at local scales. Among these techniques, which are well established, are measurements of distortions of a regular grid of marks on the sample surface [ Allais et al , ; Biery et al , ; Ghadbeigi et al , ; Karimi , ; Moulart et al , ; Wu et al , ] and determinations of local displacements using speckle patterns [ Barrientos et al , ; Dudderar et al , ; Larsson et al , ; Molin et al , ; Synnergren and Sjödahl , ] or image correlations [ Amiot et al , ; Bornert et al , ; Bruck et al , ; McNeill et al , ; McNeill et al , ; Sutton , ]. The literature is extensive, and many other papers could be cited.…”

Section: Introductionmentioning

confidence: 99%

Direct observations of damage during unconfined brittle failure of Carrara marble

2016

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To observe and quantify the production of microfracturing from initial yield to failure, we deformed Carrara marble samples in uniaxial compression at 20, 105, and 180°C and continuously observed a region of about 1 mm2 on an exposed face with a long‐working distance microscope. Using image processing and microscale strain‐mapping techniques, we measured local strains over a length scale of tens of micrometers. By treating the images with various filters, we identified linear damage features, as well as the magnitude of localized strain and the mode of deformation, i.e., shear versus normal deformation. In general, shear deformation is more prevalent after initial yielding, while tensile deformation dominates closer to peak stress. Independent measurements of both stress and microcrack density at different stages of each experiment provide a unique opportunity to explicitly compare the data with damage models. The model of Ashby and Sammis (1990) significantly underestimated the damage that the rock could sustain before peak stress, perhaps owing to the influence of weak grain boundaries on the damage production. In these samples, microcracks tended to form near boundaries before yield stress. During strain hardening, the damage parameters increased rapidly as longer microcracks grew along the boundaries and finally transected grains as loading neared peak stress. The microcrack density can be empirically related to the reduction of Young's modulus; stiffness ratios decay exponentially with increasing microcrack density for T ≤ 105°C.

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Section: Introductionmentioning

confidence: 99%

Direct observations of damage during unconfined brittle failure of Carrara marble

2016

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“…There are several methodologies to measure displacement fields, including, for example, the analysis of speckle patterns [Barrientos et al, 2004;Dudderar et al, 1983;Larsson et al, 2004;Molin et al, 2004;Pan et al, 2009;Sutton et al, 2009;Synnergren and Sjödahl, 1999] or digital image correlation [Amiot et al, 2013;Bornert et al, 2009;Bruck et al, 1989;McNeill et al, 1987McNeill et al, , 1997Sharpe, 2008]. For our microscale strain maps (MSSM), we used a grid technique [Allais et al, 1994;Ghadbeigi et al, 2012;Karimi, 1984;Moulart et al, 2007;Sharpe, 2008;Wu et al, 2006] to analyze the relative displacement of regularly spaced markers before and after deformation.…”

Section: The Mssm Techniquementioning

confidence: 99%

Heterogeneity of inelastic strain during creep of Carrara marble: Microscale strain measurement technique

Quintanilla-Terminel

Evans

2016

JGR Solid Earth

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We combined the split cylinder technique with microfabrication technology to observe strain heterogeneities that were produced during high‐pressure transient creep of Carrara marble. Samples were patterned with a custom‐designed grid of markers spaced 10 µm apart and containing an embedded coordinate system. The microscale strain measurement (MSSM) technique described here allowed us to analyze the local strain distribution with unprecedented detail over large regions. The description of the strain field is a function of the area over which strain is being computed. The scale at which the strain field can be considered homogeneous can provide insight into the deformation processes taking place. At 400–500°C, when twinning production is prolific, we observe highly strained bands that span several grains. One possible cause for the multigrain bands is the need to relieve strain incompatibilities that result when twins impinge on neighboring grains. At 600–700°C, the strain fields are still quite heterogeneous, and local strain varies substantially within grains and near grain boundaries, but the multigrain slip bands are not present. Deformation is concentrated in much smaller areas within grains and along some grain boundaries. The disappearance of the multigrain slip bands occurs when the deformation conditions allow additional slip systems to be activated. At 600°C, when the total strain is varied from 0.11 to 0.36, the spatial scale of the heterogeneity does not vary, but there are increases in the standard deviation of the distribution of local strains normalized by the total strain; thus, we conclude that the microstructure does not achieve a steady state in this strain interval.

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“…To do so, measured force-punch displacement curves have been compared to similar analytical calculations. On the other side, several optical studies have been published on different techniques to measure the out-of-plane deformation of a deforming body (see, e.g., Sainov et al, 1989;Chen et al, 1999;Martínez-Celorio et al, 2002;Salas et al, 2003;Chen et al, 2004;Su et al, 2004;Kumar et al, 2004;Barrientos et al, 2004;Tay et al, 2005). However, none of these have tried to measure the out-of-plane deformation profiles of a punched target plate at large deflections to fracture, and compared the results to detailed finite element calculations.…”

Section: Introductionmentioning

confidence: 96%

Out-of-plane deformation measurements of an aluminium plate during quasi-static perforation using structured light and close-range photogrammetry

Grytten

Fagerholt

Auestad

et al. 2007

International Journal of Solids and Structures

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An optical system using structured light and close-range photogrammetry for full-field continuous measurements of the out-of-plane deformation of a metal plate loaded at its centre by a moving punch is presented. The system is applicable both for quasi-static and dynamic loading conditions, but in this paper focus will be on the former. In the tests, a square AA5083-H116 aluminium plate is mounted in a circular frame and penetrated from above by a cylindrical punch, while the out-of-plane deformation is observed from below. A fringe pattern is projected on the target plate surface and recorded by a camera (or more than one if required). The changing fringe positions on the plate surface during perforation are then computer processed to give topography information of the out-of-plane deformation. This paper is divided into three major parts. First, the optical technique is presented with a description of the applied method, image analysis procedures, calibration of the system and estimation of accuracy of the acquired data points. The experimental set-up is then presented, and some results from a typical test where a 5 mm thick plate with free-span diameter of 500 mm is perforated by a 20 mm diameter blunt-nose punch are given. Finally, numerical simulations of the perforation process are carried out using the non-linear finite element code LS-DYNA. The numerical predictions are compared with the experimental observations and the applicability of the experimental method is discussed based on the obtained results.

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Measurement of out-of-plane deformation by combination of speckle photography and speckle shearing interferometry

Cited by 16 publications

References 13 publications

Direct observations of damage during unconfined brittle failure of Carrara marble

Direct observations of damage during unconfined brittle failure of Carrara marble

Heterogeneity of inelastic strain during creep of Carrara marble: Microscale strain measurement technique

Out-of-plane deformation measurements of an aluminium plate during quasi-static perforation using structured light and close-range photogrammetry

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