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Digital image correlation

About: Digital image correlation is a research topic. Over the lifetime, 7842 publications have been published within this topic receiving 132166 citations.


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TL;DR: High-speed imaging can provide detailed insights into phenomena including fracture, impact, fragmentation and penetration in geological materials as discussed by the authors, which can be used to advance the understanding of the mechanical response of materials to impact loading.
Abstract: Geomaterials (i.e. rock, sand, soil and concrete) are increasingly being encountered and used in extreme environments, in terms of the pressure magnitude and the loading rate. Advancing the understanding of the mechanical response of materials to impact loading relies heavily on having suitable high-speed diagnostics. One such diagnostic is high-speed photography, which combined with a variety of digital optical measurement techniques can provide detailed insights into phenomena including fracture, impact, fragmentation and penetration in geological materials. This review begins with a brief history of high-speed imaging. Section 2 discusses of the current state of the art of high-speed cameras, which includes a comparison between charge-coupled device and complementary metal-oxide semiconductor sensors. The application of high-speed photography to geomechanical experiments is summarized in Sect. 3. Section 4 is concerned with digital optical measurement techniques including photoelastic coating, Moire, caustics, holographic interferometry, particle image velocimetry, digital image correlation and infrared thermography, in combination with high-speed photography to capture transient phenomena. The last section provides a brief summary and discussion of future directions in the field.

97 citations

Journal ArticleDOI
TL;DR: In this article, the efficiency of the digital image correlation method for measuring in-plane displacements in the presence of high strain gradient is discussed, and three types of strain gradient have been studied: strain localization around a hole in a composite laminate, strain concentration at a crack tip in a TiAl alloy, and strain gradient on a polymer neck front.

97 citations

Journal ArticleDOI
TL;DR: In this article, a random representative volume element (RRVE) was proposed to estimate the elastic properties of carbon fiber/epoxy molding systems derived from chopped aerospace-grade unidirectional tape prepreg.
Abstract: Recent composite technology research and development efforts have focused on discontinuous carbon fiber/epoxy molding systems derived from chopped aerospace-grade unidirectional tape prepreg. Although the average elastic modulus of this material has been shown to be as high as that of the continuous tape quasi-isotropic benchmark, experimental measurement by means of strain gage or extensometer has shown variation as high as 20%. Digital Image Correlation can be used successfully to obtain a full-field strain measurement, and it shows that a highly non-uniform strain distribution exists on the surface of the specimen, with distinct peaks and valleys. This pattern of alternating regions of high and low strain gradients, and which exhibit a characteristic shape and size, can be described in terms of Random Representative Volume Element (RRVE). The RRVE proposed here exhibits random elastic properties, which are assigned based on stochastic distributions. This approach leads to the analysis method proposed here, which is designed to compensate for the fact that traditional methods cannot capture the experimentally observed variation in modulus within a specimen and among different specimens. The method utilizes a randomization process to generate statistical distributions of fractions and orientations of chips within the RRVE, and then applies Classical Laminated Plate Theory to an equivalent quasi-isotropic tape laminate to calculate its average elastic properties. Validation of this method is shown as it applies to a finite element model that discretizes the structure in multiple RRVEs, whose properties are generated independently of the neighboring ones, and then are solved simultaneously. The approach generates accurate predictions of the strain distribution on the surface of the specimen.

97 citations

Journal ArticleDOI
TL;DR: In this article, a model unidirectional [ 0 5 / 90 3 ] s CFRP laminate beam is impacted by a cylindrical head creating an almost uniform two-dimensional loading condition.
Abstract: Damage process in composites subjected to low-velocity impact is investigated both experimentally and numerically. Drop-weight impact experiments are carried out, in which a model unidirectional [ 0 5 / 90 3 ] s CFRP laminate beam is impacted by a cylindrical head creating an almost uniform two-dimensional loading condition. Initiation and progression of damage, consisting of matrix cracks and delamination, are visualized in real-time via ultra-high-speed camera at rates up to 60,000 fps and the sequence of failure events are clearly captured. Evolution of dynamic strain fields in the laminate is then quantified by a Digital Image Correlation (DIC) analysis and the resulting final failure patterns are characterized by a digital microscope. In the computational part, a three-dimensional finite element analysis is performed using ABAQUS/Explicit to simulate the experiments. In these simulations, the intraply matrix damage in the middle 90° layers is modeled using a Continuum Damage Mechanics (CDM) based composite failure theory with LaRC04 initiation criterion and implemented via a user-written VUMAT subroutine. Delamination is modeled using cohesive interface elements that are introduced between the 0°/90° interfaces. Damage initiation time, location and the interaction of failure modes are compared with the experimental data. Real-time observations of the sequentially occurring diagonal matrix cracking followed by dynamic delaminations are made. In addition to the major diagonal matrix cracks, existence of multiple diagonal micro-matrix cracks near the upper interface are shown which are also predicted by the simulations. Finally, experimentally obtained real-time strain field values, failure mechanisms and the failure sequence are shown to be in good agreement with the simulations. We believe that the elaborate experimental results presented here for an idealized composite layup can serve as a benchmark test case to validate composite and interface damage modeling methods.

97 citations

Journal ArticleDOI
TL;DR: In this paper, Adaptive cross correlation (ACC) is used to study two-dimensional spatial soil deformations nonintrusively, which is an advanced cross-correlation algorithm.
Abstract: Digital image correlation (DIC) is used in this paper to study two-dimensional spatial soil deformations nonintrusively. Adaptive cross correlation (ACC), which is an advanced cross-correlation alg...

96 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023582
20221,120
2021667
2020646
2019636
2018567