scholarly journals Design of a Unique Device for Residual Stresses Quantification by the Drilling Method Combining the PhotoStress and Digital Image Correlation

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 314
Author(s):  
Miroslav Pástor ◽  
Martin Hagara ◽  
Ivan Virgala ◽  
Adam Kaľavský ◽  
Alžbeta Sapietová ◽  
...  
Keyword(s):  
Digital Image Correlation ◽  
Digital Image ◽  
Experimental Testing ◽  
Digital Processing ◽  
Image Correlation ◽  
Optical Systems ◽  
Hole Drilling ◽  
Element Analysis ◽  
Thin Specimen ◽  
Comparison Of The Results

This paper presents a uniquely designed device combining the hole-drilling technique with two optical systems based on the PhotoStress and digital image correlation (DIC) method, where the digital image correlation system moves with the cutting tool. The authors aimed to verify whether the accuracy of the drilled hole according to ASTM E837-13a standard and the positioning accuracy of the device were sufficient to achieve accurate results. The experimental testing was performed on a thin specimen made from strain sensitive coating PS-1D, which allowed comparison of the results obtained by both methods. Although application of the PhotoStress method allows analysis of the strains at the edge of the cut hole, it requires a lot of experimenter’s practical skills to assess the results correctly. On the other hand, the DIC method allows digital processing of the measured data. However, the problem is not only to determine the data at the edge of the hole, the results also significantly depend on the smoothing levels used. The quantitative comparison of the results obtained was performed using finite element analysis.

scholarly journals NUMERICAL PREDICTIONS AND MECHANICAL TESTING OF BRAIDED COMPOSITE STRUCTURES UTILISING DIGITAL IMAGE CORRELATION

2016 ◽  
Vol 7 ◽  
pp. 43
Author(s):  
Emil Pitz ◽  
Matei-Constantin Miron ◽  
Imre Kállai ◽  
Zoltán Major
Keyword(s):  
Numerical Model ◽  
Digital Image Correlation ◽  
Digital Image ◽  
Composite Structures ◽  
Experimental Testing ◽  
Single Layer ◽  
Failure Criteria ◽  
Image Correlation ◽  
Braided Composites ◽  
Numerical Predictions

The current paper is describing the implementation of a multiscale numerical model for prediction of stiffness and strength in braided composites. The model is validated by experimental testing of single-layer braided tubes under torsional loading utilising digital image correlation (DIC). For the numerical model the entire braided structure is modelled at yarn detail level, taking into account the yarn behaviour as well as individual yarn-to-yarn interactions by using cohesive contact definitions. By means of Hashin’s failure criteria and cohesive contact damage, failure of the yarns and failure of the yarn-to-yarn interface is being accounted for. Thereby the material failure behaviour can be predicted. For validation of the model, torsion tests of biaxially braided single-layer composite tubes were performed. The strain distribution at the specimen surface was studied using the DIC system ARAMIS in 3D mode.

An Experimental Assessment on Umbilical Cable Crushing Using Digital Image Correlation

2016 ◽  
Author(s):  
Caio C. P. Santos ◽  
Celso P. Pesce ◽  
Guilherme R. Franzini ◽  
Olaf O. Otte Filho
Keyword(s):  
Digital Image Correlation ◽  
Cross Sections ◽  
Digital Image ◽  
Mechanical Tests ◽  
Image Correlation ◽  
Displacement Fields ◽  
Element Analysis ◽  
Analysis Methodology ◽  
Correlation System ◽  
Umbilical Cable

Focusing on the integrity of umbilical cable components during the laying operation, particularly on hoses integrity, this paper assesses displacement fields on umbilical cable cross-sections by means of a special crushing test setup. Using a high resolution Digital Image Correlation system (DIC), experiments with two umbilical cables are carried out in a 250 kN mechanical tests rig. Besides measuring the components displacements, applied crushing forces and shoes displacements are acquired. The experimental samples are taken from two HCR-hoses umbilical cables, which have been cases of study of a finite element analysis methodology, recently proposed and presented in OMAE2015, [12]. Experimental analysis and a theoretical-experimental correlation are presented, for both umbilical cables.

scholarly journals The Application of Digital Image Correlation for Measuring Residual Stress by Incremental Hole Drilling

2008 ◽  
Vol 13-14 ◽  
pp. 65-73 ◽  
Author(s):  
Jerry D. Lord ◽  
David Penn ◽  
P. Whitehead
Keyword(s):  
Residual Stress ◽  
Digital Image Correlation ◽  
Digital Image ◽  
Strain Gauge ◽  
Biaxial Stress ◽  
Image Correlation ◽  
Hole Drilling ◽  
Validation Data ◽  
Strain Fields ◽  
Incremental Hole Drilling

The measurement of residual stress using the incremental hole drilling is well established, but the main limitations with the conventional strain gauge approach are the requirements for surface preparation, the need for accurate alignment and drilling, the restricted range of hole geometries commensurate with the specific gauge designs, and the limited range of strain data averaged over the footprint of the strain gauge grid. Recent attempts to extend the method have seen the application of full field optical techniques such as electronic speckle pattern interferometry and holographic interferometry for measuring the strain fields around the hole, but these methods are sensitive to vibration and this limits their practical use to controlled laboratory environments. There are significant potential benefits therefore of using a more robust technique based on Digital Image Correlation (DIC), and work is presented in this study on the development of the method for measuring surface displacements and strain fields generated during incremental hole drilling. Some of the practical issues associated with the technique development, including the optimization of applied patterns, the development of the optical system and integration with current hole drilling equipment are discussed, and although measurements are only presented for a single load case - the equi-biaxial stress state introduced during shot peening - the novel aspect of this work is the integration of DIC measurements with incremental drilling and an application of the Integral Method analysis to measure the variation of residual stress with depth. Validation data comparing results from conventional strain gauge data and FE models is also presented.

A Comparison of Modern and Classical Experimental Methods of Mechanics in Strain Investigation

2014 ◽  
Vol 611 ◽  
pp. 501-505 ◽  
Author(s):  
Miroslav Pástor ◽  
Martin Hagara
Keyword(s):  
Digital Image Correlation ◽  
Digital Image ◽  
Correlation Method ◽  
Image Correlation ◽  
Deformation Analysis ◽  
Digital Image Correlation Method ◽  
Aluminum Sample ◽  
Correlation System ◽  
Comparison Of The Results ◽  
Different Levels

In this contribution a comparison of the results of deformation analysis performed in a classical way using strain gage and modern way, when a non-contact digital image correlation method was used, is described. Both methods were applied simultaneously for the investigation of the aluminum sample with stress concentrators loaded by tension, what prevented the investigation by different conditions. The contribution includes also the comparison of the results obtained using digital image correlation method by different levels of smoothing filters, which the software delivered together with correlation system contents.

V-Beam Thermal Actuator’s Performance Analysis Using Digital Image Correlation

2014 ◽  
Vol 658 ◽  
pp. 173-176 ◽  
Author(s):  
Radu Chiorean ◽  
Mircea Cristian Dudescu ◽  
Marius Pustan ◽  
Mihail Hărdău
Keyword(s):  
Digital Image Correlation ◽  
Digital Image ◽  
Image Correlation ◽  
Geometrical Parameters ◽  
Experimental Measurements ◽  
Simulation Data ◽  
Element Analysis ◽  
Deformation Stages ◽  
Physics Simulation ◽  
Position Shift

This paper analyses the influence of the V-beam thermal actuator’s geometrical parameters on its mechanical behavior. Experimental measurements were performed using Digital Image Correlation (DIC), which is a gray scale value tracking algorithm that evaluates the position shift of a pixel between at least two images taken at different deformation stages. These results are compared to multi-physics simulation data obtained using Finite Element Analysis (FEA) as well as to analytical values based on the electro-thermal and thermo-mechanical presented models.

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