scholarly journals Three-Dimensional Investigation of Free-Edge Effects in Laminate Composites Using X-ray Tomography and Digital Volume Correlation

2014 ◽  
Vol 55 (1) ◽  
pp. 301-311 ◽  
Author(s):  
P. Lecomte-Grosbras ◽  
J. Réthoré ◽  
N. Limodin ◽  
J.-F. Witz ◽  
M. Brieu
Keyword(s):  
Edge Effects ◽  
Three Dimensional ◽  
Free Edge ◽  
Digital Volume Correlation ◽  
Laminate Composites ◽  
X Ray

scholarly journals Digital Volume Correlation Applied to X-ray Micro-Tomography Images in Uniaxial Creep Tests on Anisotropic Clayey Rock

2020 ◽  
Vol 10 (14) ◽  
pp. 4898
Author(s):  
Hailing Shi ◽  
Jerome Hosdez ◽  
Thomas Rougelot ◽  
Shouyi Xie ◽  
Jianfu Shao ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Clayey Rock ◽  
Digital Volume Correlation ◽  
Creep Tests ◽  
Structural Anisotropy ◽  
Strain Fields ◽  
X Ray ◽  
Bedding Planes ◽  
Uniaxial Creep ◽  
Micro Tomography

Creep tests are commonly performed to characterize time-dependent deformation of geological materials. Classical measuring methods are not suitable for long term tests and not able to provide full three-dimensional strain fields. In this study, Digital Volume Correlation (DVC) is applied to X-ray micro-tomography (XRMT) images from creep tests on a hard clayey rock. In situ uniaxial compression creep tests are performed under different levels of stress and with different loading orientations with respect to the structural anisotropy of rock. Based on the XRMT images taken during the creep tests, DVC is applied to compute the full three dimensional strain fields and global averages strains of tested samples. The effects of bedding planes and hard inclusions on the non-uniform distribution of strains are analyzed.

scholarly journals Mechanisms of root reinforcement in soils: an experimental methodology using four-dimensional X-ray computed tomography and digital volume correlation

2020 ◽  
Vol 476 (2237) ◽  
pp. 20190838
Author(s):  
D. J. Bull ◽  
J. A. Smethurst ◽  
I. Sinclair ◽  
F. Pierron ◽  
T. Roose ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Three Dimensional ◽  
Shear Loading ◽  
Soil Reinforcement ◽  
Experimental Methodology ◽  
Digital Volume Correlation ◽  
X Ray ◽  
Reinforced Soils ◽  
Multi Scale ◽  
X Ray Computed

Vegetation on railway or highway slopes can improve slope stability through the generation of soil pore water suctions by plant transpiration and mechanical soil reinforcement by the roots. To incorporate the enhanced shearing resistance and stiffness of root-reinforced soils in stability calculations, it is necessary to understand and quantify its effectiveness. This requires integrated and sophisticated experimental and multi-scale modelling approaches to develop an understanding of the processes at different length scales, from individual root–soil interaction through to full soil-profile or slope scale. One of the challenges with multi-scale models is ensuring that they sufficiently closely represent real behaviour. This requires calibration against detailed high-quality and data-rich experiments. This study presents a novel experimental methodology, which combines in situ direct shear loading of a willow root-reinforced soil with X-ray computed tomography to capture the three-dimensional chronology of soil and root deformation within the shear zone. Digital volume correlation (DVC) analysis was applied to the computed tomography dataset to obtain full-field three-dimensional displacement and strain information. This paper demonstrates the feasibility and discusses the challenges associated with DVC experiments on root-reinforced soils.

Digital volume correlation: Three-dimensional strain mapping using X-ray tomography

1999 ◽  
Vol 39 (3) ◽  
pp. 217-226 ◽  
Author(s):  
B. K. Bay ◽  
T. S. Smith ◽  
D. P. Fyhrie ◽  
M. Saad
Keyword(s):  
Three Dimensional ◽  
Digital Volume Correlation ◽  
Strain Mapping ◽  
X Ray

scholarly journals 3D Studies of Indentation by Combined X-Ray Tomography and Digital Volume Correlation

2013 ◽  
Vol 592-593 ◽  
pp. 14-21 ◽  
Author(s):  
Mahmoud Mostafavi ◽  
Yelena Vertyagina ◽  
Christina Reinhard ◽  
Robert Bradley ◽  
Xia Jiang ◽  
...  
Keyword(s):  
Crack Opening ◽  
Three Dimensional ◽  
Image Correlation ◽  
Digital Volume Correlation ◽  
Surface Characterisation ◽  
X Ray ◽  
Element Simulation ◽  
Potential Applications ◽  
Deformation Processes ◽  
X Ray Computed

Hardness testing obtains material properties from small specimens via measurement of load-displacement response to an imposed indentation; it is a surface characterisation technique so, except in optically transparent materials, there is no direct observation of the assumed damage and deformation processes within the material. Three-dimensional digital image correlation (digital volume correlation) is applied to study deformation beneath indentations, mapping the relative displacements between high-resolution synchrotron X-ray computed tomographs (0.9 μm voxel size). Two classes of material are examined: ductile aluminium-silicon carbide composite (Al-SiC) and brittle alumina (Al2O3). The measured displacements for Hertzian indentation in Al-SiC are in good agreement with an elastic-plastic finite element simulation. In alumina, radial cracking is observed beneath a Vickers indentation and the crack opening displacements are measured, in situ under load, for the first time. Potential applications are discussed of this characterization technique, which does not require resolution of microstructural features.

scholarly journals Extended Kantorovich method for coupled piezoelasticity solution of piezolaminated plates showing edge effects

2013 ◽  
Vol 469 (2151) ◽  
pp. 20120565 ◽  
Author(s):  
Santosh Kapuria ◽  
Poonam Kumari
Keyword(s):  
Edge Effects ◽  
Electric Potential ◽  
Three Dimensional ◽  
Single Layer ◽  
Free Edge ◽  
Laminated Plates ◽  
Kantorovich Method ◽  
Extended Kantorovich Method ◽  
Hybrid Laminates ◽  
Laminated Panels

The powerful extended Kantorovich method (EKM) originally proposed by Kerr in 1968 is generalized to obtain a three-dimensional coupled piezoelasticity solution of smart piezoelectric laminated plates in cylindrical bending. Such solutions are needed to accurately predict the edge effects in these laminates under electromechanical loading. The Reissner-type mixed variational principle extended to piezoelasticity is used to develop the governing equations in terms of displacements, electric potential as well as stresses and electric displacements. It allows for exact satisfaction of the boundary conditions, including the non-homogeneous ones at all points. An n -term solution generates a set of 11 n algebraic ordinary differential equations in the inplane direction and a similar set in the thickness direction for each lamina, which are solved in closed form. The multi-term EKM is shown to predict the coupled electromechanical response, including the edge effects, of single-layer piezoelectric sensors as well as hybrid laminated panels accurately, for both pressure and electric potential loadings. This work will facilitate development of accurate semi-analytical solutions of many other unresolved problems in three-dimensional piezoelasticity, such as the free-edge stresses in hybrid laminates under bending, tension and twisting.

LED Chip Deformation Measurement During the Operation Using the X-Ray CT Digital Volume Correlation

2015 ◽  
Author(s):  
Pradeep Lall ◽  
Junchao Wei
Keyword(s):  
Three Dimensional ◽  
Ct Scanning ◽  
Image Correlation ◽  
Reference Image ◽  
Digital Volume Correlation ◽  
X Ray ◽  
Function Computation ◽  
Fixed Subset ◽  
Three Dimensional Measurement ◽  
Strain Components

A high-power LED can generate tremendous heat under the operation, which causes the LED chip undergo large deformation. LED Wire Bonds may undergo deformation because of the mismatch between the LED chip and substrate. Presently, measurements of deformation and strain in operational electronics are limited to measurement on a cut-plane using techniques including digital image correlation and moiré interferometry based techniques. There is need for tools and techniques that can help quantify the in-situ chip deformation and interconnects inside the LED. Digital Volume Correlation (DVC) has been used in conjunction with X-ray Micro-CT for three-dimensional measurement of deformation and strain in LEDs under operational stresses. The Digital Volume Correlation has been used to correlate the undeformed image with deformed images by computing correlation functions throughout each voxel. The deformed images have been generated by CT scanning over the object while the LED is operational. The correlation function computation starts at specific fixed subset window in the reference image, and searches every possible subset window in the deformed image to identify the deformation in the electronic structure. Once the displacement components have been derived, the strain components have been computed by calculating the gradients of the displacement field. In this paper, the full strain field, both in-plane and out-plane strain, will be presented, and the LED chip deformation shape will be analyzed.

scholarly journals Three-dimensional Analysis of an In Situ Double-torsion Test by X-ray Computed Tomography and Digital Volume Correlation

2013 ◽  
Vol 53 (7) ◽  
pp. 1265-1275 ◽  
Author(s):  
P. Leplay ◽  
J. Réthoré ◽  
S. Meille ◽  
M.-C. Baietto ◽  
J. Adrien ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Dimensional Analysis ◽  
Three Dimensional ◽  
Torsion Test ◽  
Digital Volume Correlation ◽  
X Ray ◽  
X Ray Computed ◽  
Double Torsion
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