Application of Digital Image Correlation (DIC) to the Measurement of Strain Concentration of a PVA Dual-Crosslink Hydrogel Under Large Deformation

2019 ◽  
Vol 59 (7) ◽  
pp. 1021-1032 ◽  
Author(s):  
M. Liu ◽  
J. Guo ◽  
C.-Y. Hui ◽  
A. T. Zehnder
Optik ◽  
2014 ◽  
Vol 125 (18) ◽  
pp. 5316-5322 ◽  
Author(s):  
Xiang Guo ◽  
Jin Liang ◽  
Zhenzhong Xiao ◽  
Binggang Cao

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Hong He ◽  
Rong Zhou ◽  
Yuanwen Zou ◽  
Xuejin Huang ◽  
Jinchuan Li

Cell mechanical stretching in vitro is a fundamental technique commonly used in cardiovascular mechanobiology research. Accordingly, it is crucial to measure the accurate strain field of cell substrate under different strains. Digital image correlation (DIC) is a widely used measurement technique, which is able to obtain the accurate displacement and strain distribution. However, the traditional DIC algorithm used in digital image correlation engine (DICe) cannot obtain accurate result when utilized in large strain measurement. In this paper, an improved method aiming to acquire accurate strain distribution of substrate in large deformation was proposed, to evaluate the effect and accuracy, based on numerical experiments. The results showed that this method was effective and highly accurate. Then, we carried out uniaxial substrate stretching experiments and applied our method to measure strain distribution of the substrate. The proposed method could obtain accurate strain distribution of substrate film during large stretching, which would allow researchers to adequately describe the response of cells to different strains of substrate.


2005 ◽  
Author(s):  
Helena (Huiqing) Jin ◽  
Wei-Yang Lu ◽  
Simon Scheffel ◽  
Michael K. Neilsen ◽  
Terry D. Hinnerichs

Polyurethane foams have good energy absorption properties and are effective in protecting sensitive components from damages due to impact. The foam absorbs impact energy by crushing cells and undergoing large deformation. The complex deformation of the foam needs to be modeled accurately to simulate the impact events. In this paper, the Digital Image Correlation (DIC) technique was implemented to obtain the deformation field of foam specimens under compression tests. Images of foam specimen were continuously acquired using high-speed cameras. The full field displacement and strain at each incremental step of loading were calculated from these images. The closed-cell polyurethane foam used in this investigation was nominal 0.32 kg/m^3 (20 pcf). In the first experiment, cubic specimens were compressed uniaxially up to 60%. The full-field displacements and strains obtained using the DIC technique provide detailed information about the inhomogeneous deformation over the area of interest during loading. In the second experiment, compression tests were conducted for a simple foam structure - cubic foam specimens with a steel cylinder inclusion. The strain concentration at the interface between steel cylinder and foam was studied to simulate the deformation of foam in a typical application. In the third experiment, the foam was loaded from the steel cylinder during the compression. The strain concentration at the interface and the displacement distribution over the surface were compared for cases with and without a confinement fixture to study the effects of confinement. These experimental results demonstrate that the DIC technique can be applied to polyurethane foams to study the heterogeneous deformation. The experimental data is briefly compared with the results from modeling and simulation using a viscoplastic model for the foam.


2015 ◽  
Vol 665 ◽  
pp. 209-212
Author(s):  
Dong Chang Li ◽  
Huang Chao ◽  
Qu Jia

Rubber material is non-linear, hyper-elastic and incompressible. Its complex mechanical properties increase the difficulties of the theoretical calculation in large deformation. As the development of computing capacity and optical sensors, DIC (Digital Image Correlation) method has become an important method in measuring large deformation of rubber material. In this paper, DIC method was used to measure different depth of burial defective rubber in tensile test, the result, however, failed to test the burial defects of rubber sheet. In order to explore the failure mechanism, the finite element simulation test is completed using Mooney-Rivlin material model of two parameters. The undetected phenomenon is caused by rubber’s hyper elasticity and low-rigidity. The results show that DIC method can be effectively applied to the measurement and evaluation of mechanical properties of rubber-like material’s surface defects, but not its burial defects. The fact that DIC method is unable to detect the burial defects of rubber sheet should be paid more attention.


2021 ◽  
pp. 2150003
Author(s):  
Zixu Guo ◽  
Ziyuan Song ◽  
Dawei Huang ◽  
Xiaojun Yan

In this paper, a digital image correlation (DIC) method is developed and applied on film cooling holes in the submillimeter scale in high temperature. Compared with the traditional DIC method, the speckle patterning method and the optical system are improved. In detail, a kind of high temperature-resistant black paint is selected as the basecoat, and the white ZrO2 particles are evenly distributed on the specimen using high-pressure splashing method. Besides, to eliminate the radiation effect of the high-temperature specimen, the blue light source is used to illuminate the specimen, and the optical bandpass filter is placed in front of the camera to allow the blue light passing. In order to verify the DIC method, the strain measurement on a specimen with single skew hole is performed. The relative error in high temperature of the maximum strain between the measurement results and the numerical simulation results given by the finite element method (FEM) is 12%. The strain concentration factor of the single skew hole is measured as 1.83. Finally, the developed method is applied to the strain measurement of the structure with multiple film cooling holes in 870°C. The X-shape strain distribution can be observed at the hole with maximum stress, which suggests that the strain field of multiple holes has coupling effect. In addition, the strain concentration factor of multiple film cooling holes increases to 2.34.


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