scholarly journals Uniaxial Static Stress Estimation for Concrete Structures Using Digital Image Correlation

Sensors ◽  
2019 ◽  
Vol 19 (2) ◽  
pp. 319 ◽  
Author(s):  
Junhwa Lee ◽  
Eun Kim ◽  
Seongwoo Gwon ◽  
Soojin Cho ◽  
Sung-Han Sim
Keyword(s):  
Stress Relaxation ◽  
Digital Image Correlation ◽  
Digital Image ◽  
Displacement Field ◽  
Concrete Structures ◽  
Estimation Method ◽  
Static Stress ◽  
Image Correlation ◽  
Accurate Estimation ◽  
Stress Estimation

This paper proposes a static stress estimation method for concrete structures, using the stress relaxation method (SRM) in conjunction with digital image correlation (DIC). The proposed method initially requires a small hole to be drilled in the concrete surface to induce stress relaxation around the hole and, consequently, a displacement field. DIC measures this displacement field by comparing digital images taken before and after the hole-drilling. The stress level in the concrete structure is then determined by solving an optimization problem, designed to minimize the difference between the displacement fields from DIC and the one from a numerical model. Compared to the pointwise measurements by strain gauges, the full-field displacement obtained by DIC provides a larger amount of data, leading to a more accurate estimation. Our theoretical results were experimentally validated using concrete specimens, demonstrating the efficacy of the proposed method.

scholarly journals Stress Estimation Using Digital Image Correlation with Compensation of Camera Motion-Induced Error

Sensors ◽  
2019 ◽  
Vol 19 (24) ◽  
pp. 5503
Author(s):  
Junhwa Lee ◽  
Seunghoo Jeong ◽  
Young-Joo Lee ◽  
Sung-Han Sim
Keyword(s):  
Digital Image Correlation ◽  
Digital Image ◽  
Imaging System ◽  
Mathematical Formulation ◽  
Estimation Method ◽  
Image Correlation ◽  
Hole Drilling ◽  
Camera Motion ◽  
Engineering Structures ◽  
Stress Estimation

Measurement of stress levels from an in-service structure can provide important and useful information regarding the current state of a structure. The stress relaxation method (SRM) is the most conventional and practical method, which has been widely accepted for measuring residual stresses in metallic materials. The SRM showed strong potential for stress estimation of civil engineering structures, when combined with digital image correlation (DIC). However, the SRM/DIC methods studied thus far have practical issues regarding camera vibration during hole drilling. To minimize the error induced by the camera motion, the imaging system is installed at a distance from the specimen resulting in the low pixel density and the large extent of the inflicted damage. This study proposes an SRM/DIC-based stress estimation method that allows the camera to be removed during hole drilling and relocated to take the after-drilling image. Since the imaging system can be placed as close to the specimen as possible, a high pixel density can be achieved such that subtle displacement perturbation introduced by a small damage can be acquired by DIC. This study provides a detailed mathematical formulation for removing the camera relocation-induced false displacement field in the DIC result. The proposed method is validated numerically and experimentally.

scholarly journals Multiscale displacement field measurements of compressed mineral-wool samples by digital image correlation

2002 ◽  
Vol 41 (32) ◽  
pp. 6815 ◽  
Author(s):  
François Hild ◽  
Bumedijen Raka ◽  
Maud Baudequin ◽  
Stéphane Roux ◽  
Florence Cantelaube
Keyword(s):  
Digital Image Correlation ◽  
Digital Image ◽  
Displacement Field ◽  
Field Measurements ◽  
Mineral Wool ◽  
Image Correlation

Digital Image Correlation as a Tool for Monitoring Crack Networks on the Surface of MgO-Based Refractory Castables

2014 ◽  
Vol 92 ◽  
pp. 242-247
Author(s):  
Rafael G.M. Saracura ◽  
Rodrigo B. Canto ◽  
Victor Carlos Pandolfelli ◽  
Nicolas Schmitt ◽  
François Hild
Keyword(s):  
Digital Image Correlation ◽  
Digital Image ◽  
Displacement Field ◽  
Digital Camera ◽  
Experimental Results ◽  
Image Correlation ◽  
Post Processing ◽  
Climatic Chamber ◽  
Refractory Castables

This paper deals with the characterization of crack networks on the surface of refractory castable slabs, which are induced by stresses arising during the curing and drying (CD) stages. Images of the surface of castable samples placed in a house-made climatic chamber were recorded during the CD stages with a digital camera and processed by Digital Image Correlation (DIC) tomeasure the displacement field. Post-processing of DIC results were performed to estimate the length, orientation and opening of cracks in networks. The methodology is detailed and first analyses of experimental results are shown.

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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