scholarly journals Study of size effect using digital image correlation

2015 ◽  
Vol 8 (3) ◽  
pp. 323-340 ◽  
Author(s):  
A. H. A. SANTOS ◽  
R. L. S. PITANGUEIRA ◽  
G. O. RIBEIRO ◽  
R. B. CALDAS
Keyword(s):  
Digital Image Correlation ◽  
Size Effect ◽  
Digital Image ◽  
Concrete Beams ◽  
Image Correlation ◽  
Displacement Fields ◽  
Bending Tests ◽  
Three Point Bending ◽  
New Methods ◽  
Dic Technique

Size effect is an important issue in concrete structures bearing in mind that it can influence many aspects of analysis such as strength, brittleness and structural ductility, fracture toughness and fracture energy, among others. Further this, ever more new methods are being developed to evaluate displacement fields in structures. In this paper an experimental evaluation of the size effect is performed applying Digital Image Correlation (DIC) technique to measure displacements on the surface of beams. Three point bending tests were performed on three different size concrete beams with a notch at the midspan. The results allow a better understanding of the size effect and demonstrate the efficiency of Digital Image Correlation to obtain measures of displacements.

Parametric Study of DIC Technology for Strain Distribution of CuZn30 during Micro-Bending Process

2016 ◽  
Vol 861 ◽  
pp. 222-226
Author(s):  
Li Jie Wang ◽  
Brad Kinsey
Keyword(s):  
Digital Image Correlation ◽  
Digital Image ◽  
Parametric Study ◽  
Strain Distribution ◽  
Metal Sheet ◽  
Image Correlation ◽  
Step Size ◽  
Three Point Bending ◽  
Bending Process ◽  
Dic Technique

In this paper, digital image correlation (DIC) technology and equipment were applied to research strain distribution of CuZn30 metal sheet throughout thickness during three-point bending process. Especially, a parametric study of DIC technique was conducted. The results show that the subset value and step size has a great impact on the strain distribution date. In order to obtain a lower iterations and confidence of the image, reasonable step size and subset value should be decided.

Displacement Smoothing and Strain Estimation Using Savitaky-Golay Filters in Digital Image Correlation

2006 ◽  
Vol 326-328 ◽  
pp. 135-138 ◽  
Author(s):  
Bing Pan ◽  
Hui Min Xie ◽  
Tao Hua ◽  
Wei Ning Wang ◽  
Yan Fang
Keyword(s):  
Digital Image Correlation ◽  
Digital Image ◽  
Image Correlation ◽  
Uniaxial Tensile ◽  
Two Dimensional ◽  
Displacement Fields ◽  
Strain Fields ◽  
Three Point Bending ◽  
Strain Estimation

Recently, many research works were concentrated on how to improve the accuracy of displacement fields in digital image correlation (DIC). However, the original displacement fields calculated at discrete locations using DIC are unavoidably contaminated by noises. If the strain fields are directly computed by differentiating the original displacement fields, the noises will be amplified even at a higher level and the resulting strain fields are untrustworthy. To acquire reliably estimation of strain fields, in this paper, Savitaky-Golay (SG) filters are introduced to obtain smoothed displacement fields and reasonable strain estimation. The principle of two-dimensional SG filters is described in detail first. Then images of uniaxial tensile and three-point bending experiments were used to verify the proposed approach. The resulting smoothed displacement fields and strain fields clearly show that the proposed method is simple and effective.

Comparison of Digital Image Correlation (DIC) Technique with Nanomaterial-Based Sensor for the Analysis of Strain Measurements

2021 ◽  
pp. 2150032
Author(s):  
A. Deepak ◽  
D. F. L. Jenkins
Keyword(s):  
Digital Image Correlation ◽  
Digital Image ◽  
Standard Specimen ◽  
Strain Sensor ◽  
Constant Load ◽  
Strain Sensors ◽  
Image Correlation ◽  
Strain Measurements ◽  
American Society ◽  
Dic Technique

Digital Image Correlation (DIC) techniques can be used to visually map and measure strain in materials such as metals and metallic alloys. The strain induced in an American Society for Testing and Materials (ASTMs) standard specimen can be measured using a DIC technique. Image patterns indicating the localized strain variations as a function of time for the constant load applied were also obtained. Results obtained using the DIC technique were more accurate compared to conventional strain sensors. DIC results were also compared with nanomaterial-based strain sensor output. Localized strain induced in the material can be visualized and quantified analytically using DIC.

scholarly journals Investigation by Digital Image Correlation of Mixed Mode I and II Fracture Behavior of Metallic IASCB Specimens with Additive Manufactured Crack-Like Notch

Metals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 400 ◽  
Author(s):  
Ivo Campione ◽  
Tommaso Maria Brugo ◽  
Giangiacomo Minak ◽  
Jelena Janković Tomić ◽  
Nebojša Bogojević ◽  
...  
Keyword(s):  
Digital Image Correlation ◽  
Digital Image ◽  
Mixed Mode ◽  
Fracture Behavior ◽  
Selective Laser Sintering ◽  
Local Stress ◽  
Fatigue Loading ◽  
Image Correlation ◽  
Mode I ◽  
Displacement Fields

This work investigates the fracture behavior of maraging steel specimens manufactured by the selective laser sintering (SLS) technology, in which a crack-like notch (sharp notch) was directly produced during the additive manufacturing (AM) process. For the evaluation of the fracture toughness, the inclined asymmetrical semi-circular specimen subjected to three points loading (IASCB) was used, allowing to cover a wide variety of Mode I and II combinations. The effectiveness of manufacturing crack-like notches via the SLS technique in metals was evaluated by comparing the obtained experimental results with the ones obtained with pre-cracks induced by fatigue loading. The investigation was carried out by using the digital image correlation (DIC) technique, that allowed the evaluation of the full displacement fields around the crack tip. The displacement field was then used to compute the stress intensity factors (SIFs) for various combinations of Mode I and II, via a fitting technique which relies on the Williams’ model for the displacement. The SIFs obtained in this way were compared to the results obtained with the conventional critical load method. The results showed that the discrepancy between the two methods reduces by ranging from Mode I to Mode II loading condition. Finally, the experimental SIFs obtained by the two methods were described by the mixed mode local stress criterium.

Digital Image Correlation Based Method of Crack Growth Rate and Fracture Toughness Measurements on Mini-Samples

2013 ◽  
Vol 586 ◽  
pp. 96-99
Author(s):  
Tomasz Brynk ◽  
Anatolii Laptiev ◽  
Oleksandr Tolochyn ◽  
Zbigniew Pakiela
Keyword(s):  
Digital Image Correlation ◽  
Digital Image ◽  
Mechanical Tests ◽  
Image Correlation ◽  
Optical Measurements ◽  
Displacement Fields ◽  
Strain Measurements ◽  
Special Approach ◽  
Tip Position ◽  
Sintering Method

Modern materials fabrication methods which utilize severe plastic deformation (SPD) do not often allow to obtain enough volume of material to prepare standardized samples for mechanical tests. Therefore, there is a need for mini-samples testing. Mini-samples tests require special approach in terms of precise strain measurements. Accurate strain measurements may be achieved by means of non-contact optical method, namely Digital Image Correlation (DIC). The aim of this work is to present the methodology and results of mini-samples tests in which displacement fields measurements performed by means of DIC and inverse method were utilized for calculation of stress intensity factors and crack tip position tracking. The influence of the subarea of optical measurements for which calculation were performed on the calculations results has been investigated during tests in SPD processed Al alloys and brittle WC-Co sinters produced by means of impact sintering method.

Development of a Railway Track Displacement Monitoring by Using Digital Image Correlation Technique

2014 ◽  
Vol 548-549 ◽  
pp. 683-687 ◽  
Author(s):  
Lenny Iryani ◽  
Hery Setiawan ◽  
Tatacipta Dirgantara ◽  
Ichsan Setya Putra
Keyword(s):  
Digital Image Correlation ◽  
Stress Field ◽  
Digital Image ◽  
Displacement Field ◽  
Image Correlation ◽  
Railway Track ◽  
Remaining Life ◽  
Full Field ◽  
Field Displacement ◽  
Dic Technique

To avoid an unnecessary catastrophic accident due to a failure of a railway track, it is important to have a reliable condition monitoring system for the railway track. The integrity of the railway track can be assessed by monitoring the displacement field of the track, which can then be used to determine the strain and stress field. By knowing the stress history of the track and the S–N curves of the track material, the remaining life of the railway track can be predicted. In the present work, a simple system to monitor and record the displacement field of the railway track has been developed by using Digital Image Correlation (DIC) technique. The set–up to monitor the displacement field of the railway track was developed using a high speed video camera of Nikon J1 to capture the image of the railway track when the train passing through. The DIC technique was then employed off line to measure the displacement field of the 2D image captured. The results showed that the full field displacement measured by using DIC technique gives a good agreement compared to the finite element results. The full field displacement can be used to calculate the strain-stress field, and later on the remaining life assessment can be conducted based on the results.

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