Evaluation of the VDA 238-100 Tight Radius Bending Test using Digital Image Correlation Strain Measurement

As hybrid carbon-aramid composites become widely used in various industries, it has become imperative to mechanically characterize them using accurate methods of measuring the entire deformation field such as the digital image correlation (DIC) method. The accuracy of the numerical simulation of carbon-aramid composite structures depends on the accuracy of the elastic constants. Therefore, the goal of this research is to model and simulate the mechanical behaviour of the composite based on epoxy resin reinforced with carbon-aramid woven fabric by considering the mechanical properties investigated by tensile test combined with DIC and the bending test. The curves of the transverse strains related to the longitudinal strains were investigated using DIC in order to determine the Poisson’s ratios in the case of tensile tests applied in warp or weft directions of the reinforcement fabric. The impact strength determined by Charpy tests is also reported. The other main objective is to use the analytical models to compute the tensile and flexural moduli of elasticity for the fictitious orthotropic materials which behave similarly to the carbon-aramid composite investigated. The simulations regarding the behaviour of the carbon-aramid composite in tensile and bending tests were validated by the experimental results, since the maximum errors recorded between experimental and theoretical results were 0.19% and 0.15% for the equivalent tensile modulus and for the equivalent flexural modulus, respectively.

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A Review of Surface Deformation and Strain Measurement Using Two-Dimensional Digital Image Correlation

Metrology and Measurement Systems ◽

10.1515/mms-2016-0028 ◽

2016 ◽

Vol 23 (3) ◽

pp. 461-480 ◽

Cited By ~ 36

Author(s):

Sze-Wei Khoo ◽

Saravanan Karuppanan ◽

Ching-Seong Tan

Keyword(s):

Digital Image Correlation ◽

Digital Image ◽

Strain Measurement ◽

Surface Deformation ◽

Optical Measurement ◽

Image Correlation ◽

Two Dimensional ◽

Full Field ◽

Computation Efficiency ◽

Dimensional Measurements

Abstract Among the full-field optical measurement methods, the Digital Image Correlation (DIC) is one of the techniques which has been given particular attention. Technically, the DIC technique refers to a non-contact strain measurement method that mathematically compares the grey intensity changes of the images captured at two different states: before and after deformation. The measurement can be performed by numerically calculating the displacement of speckles which are deposited on the top of object’s surface. In this paper, the Two-Dimensional Digital Image Correlation (2D-DIC) is presented and its fundamental concepts are discussed. Next, the development of the 2D-DIC algorithms in the past 33 years is reviewed systematically. The improvement of 2DDIC algorithms is presented with respect to two distinct aspects: their computation efficiency and measurement accuracy. Furthermore, analysis of the 2D-DIC accuracy is included, followed by a review of the DIC applications for two-dimensional measurements.

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High temperature strain measurement method by combining digital image correlation of laser speckle and improved RANSAC smoothing algorithm

Optics and Lasers in Engineering ◽

10.1016/j.optlaseng.2018.07.012 ◽

2018 ◽

Vol 111 ◽

pp. 8-18 ◽

Cited By ~ 13

Author(s):

Jinlian Song ◽

Jianhong Yang ◽

Fujia Liu ◽

Kefei Lu

Keyword(s):

High Temperature ◽

Digital Image Correlation ◽

Digital Image ◽

Strain Measurement ◽

Measurement Method ◽

Laser Speckle ◽

Image Correlation ◽

Smoothing Algorithm ◽

Temperature Strain

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Tension and compression moduli characterization of a bimodular ceramic-fiber reinforced SiO2 aerogel composite

Materials Testing ◽

10.1515/mt-2020-621008 ◽

2020 ◽

Vol 62 (10) ◽

pp. 1003-1009

Author(s):

Yantao Sun ◽

Jia Huang ◽

Duoqi Shi ◽

Shengliang Zhang ◽

Zhizhong Fu ◽

...

Keyword(s):

Digital Image Correlation ◽

Digital Image ◽

Image Correlation ◽

Bending Test ◽

Ceramic Fiber ◽

Fiber Reinforced ◽

Compression Tests ◽

Tension Tests ◽

Aerogel Composite ◽

Tension And Compression

Abstract Comprehensive characterization mechanical properties of aerogels and their composites are important for engineering design. In particular, some aerogel composites were reported to have varied tension and compression moduli. But conducting tension tests is difficult for the reason that low strength and brittleness will lead to unexpected failure in the non-test area. A method is presented for measuring both the tension and compression moduli of a ceramic-fiber reinforced SiO2 aerogel composite by bending via digital image correlation. First, the relationship between bending behavior and the tension/compression moduli was introduced for bimodular materials. Then a bending test was conducted to predict tension and the compression moduli of the ceramicfiber- reinforced SiO2 aerogel composite via digital image correlation. In addition, uniaxial tension and compression tests of the aerogel composites were carried out, respectively for measuring tension and compression moduli. The tension and compression moduli measured were numerically similar to results obtained from uniaxial tests with a difference of less than 14 %.

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