Development of the Device with a High Positioning Accuracy Serving for Residual Stress Quantification using Optical Methods

Pástor, Miroslav; Čarák, Peter; Hagara, Martin

doi:10.21496/ams.2020.005

Cited by 2 publications

(2 citation statements)

References 21 publications

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“…Knowledge and consideration of residual stresses is extremely important, especially in welded structures in which they occur mainly due to significant temperature effects in the area around the weld and subsequent uneven cooling. Residual stresses in a structure can arise not only during its production but also during repairs or as a result of possible overload [ 21 , 22 , 23 , 24 , 25 , 26 ]. These stresses are superimposed on stresses from the operating load, which can reduce, sometimes substantially, safety and reliability of the load-bearing element and thus of the entire structure.…”

Section: Determination Of Residual Stresses On Sluice Gatementioning

confidence: 99%

Experimental and Numerical Analysis of 60-Year-Old Sluice Gate Affected by Long-Term Operation

et al. 2020

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Technological units of water reservoirs and power plants include sluice gates which are designed to completely seal the inflow or outflow of water in supply or discharge channels. This article describes the issue of technical assessment of a sluice gate made in the 1950s. Such structures are characterised by states of significant corrosive wear, permanent deformations of contact and sealing surfaces as well as increased levels of residual stresses. In such cases, it is difficult to determine service life using only numerical modelling methods, mainly due to problematic definition of material properties and boundary conditions. Therefore, for safety assessment, it is necessary to verify these facts experimentally. This article presents the procedure for assessing safe operation of the sluice gate on which places with permanent deformation and a broken part of the guide wheel flange were identified. By means of numerical modelling, we identified critical stress values at the locations of reinforcing elements, which were modified, and the stress values were reduced by about 15%. The results of numerical modelling were verified at select locations by experimental measurements during operation using strain gauges. The maximum values of operational normal stresses in the assessed places reached about 27 MPa. Based on the comparison of obtained results and taking into account values of residual stresses reaching up to 190 MPa made by shielded metal arc welding, it can be stated that, for safe operation of the sluice gate, it is necessary to follow the proposed procedure during its lowering and to modify the reinforcing elements structurally.

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Section: Determination Of Residual Stresses On Sluice Gatementioning

confidence: 99%

Experimental and Numerical Analysis of 60-Year-Old Sluice Gate Affected by Long-Term Operation

et al. 2020

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“…Unlike drilling devices designed by other authors, this device is unique in that it allows horizontal and vertical movement of not only the milling cutter but also the correlation system (Fig. 2) and thus, the images can be acquired with the desired quality from a suitable distance for different specimen shapes and thicknesses [8]. The proposed device was tested for structural rigidity, positioning accuracy and blind-hole formation [9].…”

Section: Introductionmentioning

confidence: 99%

A Complex Review of the Possibilities of Residual Stress Analysis Using Moving 2D and 3D Digital Image Correlation System

Hagara

Pástor

2021

Strojnícky Časopis - Journal of Mechanical Engineering

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Understanding the levels of residual stresses in the material is very important in predicting the service life of structural elements. One of the most widely used techniques to quantify them is the drilling method, where a small hole is milled in the structure. If the residual stresses are present, stress redistribution will occur, resulting in deformation of the hole surroundings. Nowadays, there is an effort to replace the conventionally used strain gauges, i.e. special strain gauge rosettes, with full-field optical experimental techniques. This paper deals with analysing the possibilities of measuring the relieved strains/stresses with a unique drilling/measuring device, which, unlike other non-commercial measuring systems, uses the moving digital image correlation (DIC) system. Since correlation systems do not tend to move during operation, an analysis was performed describing the effect of changing the position of the single and stereo camera correlation systems on the quality of the results of the strain/stress analysis performed in the vicinity of the milled hole. The conclusion from the analyses performed is that there is no significant accumulation of correlation errors during measurement. Therefore, the information on the magnitudes of the strains/stresses relieved obtained by the moving DIC system can be used to quantify the residual stresses with an expected error corresponding to the sensitivity of this full-field optical experimental technique.

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Development of the Device with a High Positioning Accuracy Serving for Residual Stress Quantification using Optical Methods

Cited by 2 publications

References 21 publications

Experimental and Numerical Analysis of 60-Year-Old Sluice Gate Affected by Long-Term Operation

Experimental and Numerical Analysis of 60-Year-Old Sluice Gate Affected by Long-Term Operation

A Complex Review of the Possibilities of Residual Stress Analysis Using Moving 2D and 3D Digital Image Correlation System

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