Technology and Equipment for Determination of Residual Stresses in Welded Structures Based on the Application of Electron Speckle-Interferometry

2013 ◽  
Vol 768-769 ◽  
pp. 166-173 ◽  
Author(s):  
Leonid Lobanov ◽  
Vyacheslav Pivtorak ◽  
Viktor Savitsky ◽  
Galina Tkachuk
Keyword(s):  
Residual Stresses ◽  
Turbine Rotor ◽  
Speckle Interferometry ◽  
Hole Drilling ◽  
Structural Elements ◽  
New Approach ◽  
Welded Structures ◽  
Hole Drilling Method ◽  
Drilling Method

The technology and equipment for determination of residual stresses in the welded structures, using electron speckle-interferometry combined with the hole-drilling method (ESPI-HD), have been described. A special new approach to the conventional method of speckle-interferometry to investigate the stress gradients over the test object surface has been added. The developed equipment has been applied for determination of residual stresses in the different structures: the gas-turbine rotor, the welded shell and the structural elements with the large grain size.

Residual Stress Analysis in Containers for Transport of Radioactive Materials

2015 ◽  
Vol 732 ◽  
pp. 28-31 ◽  
Author(s):  
František Trebuňa ◽  
František Šimčák ◽  
Miroslav Pástor ◽  
Patrik Šarga
Keyword(s):  
Residual Stresses ◽  
Experimental Methods ◽  
Hole Drilling ◽  
Thermal Processes ◽  
Safe Operation ◽  
Radioactive Materials ◽  
Hole Drilling Method ◽  
Drilling Method ◽  
Residual Stress Analysis

During verification of safe operation of containers for radioactive waste is possible to use analytical, numerical and experimental methods of mechanics. Determination of residual stresses was one part of analysis. The residual stresses in container body can be induced during their production, overloading during operation, radiation or by thermal processes. In the paper are presented results from analysis of residual stresses in containers by using strain-gage hole-drilling method.

Reduce the Residual Stress of Welded Structures by Post-Weld Vibration

2005 ◽  
Vol 490-491 ◽  
pp. 102-106 ◽  
Author(s):  
De Lin Rao ◽  
Zheng Qiang Zhu ◽  
Li Gong Chen ◽  
Chunzhen Ni
Keyword(s):  
Residual Stress ◽  
Stainless Steel ◽  
Residual Stresses ◽  
Mechanical Vibration ◽  
Welding Process ◽  
Hole Drilling ◽  
Welded Structures ◽  
Hole Drilling Method ◽  
Drilling Method ◽  
Before And After

The existence of residual stresses caused by the welding process is an important reason of cracking and distortion in welded metal structures that may affect the fatigue life and dimensional stability significantly. Heat treatment is one of the traditional methods to relieve the residual stresses. But it is often limited by the manufacturing condition and the size of the structures. In this paper a procedure called vibratory stress relief (VSR) is discussed. VSR is a process to reduce and re-distribute the internal residual stresses of welded structures by means of post-weld mechanical vibration. The effectiveness of VSR on the residual stresses of welded structures, including the drums of hoist machine and thick stainless steel plate are investigated. Parameters of VSR procedure are described in the paper. Residual stresses on weld bead are measured before and after VSR treatment by hole-drilling method and about 30%~50% reduction of residual stresses are observed. The results show that VSR process can reduce the residual stress both middle carbon steel (Q345) and stainless steel (304L) welded structures effectively.

Hole-Within-a-Hole Method for Determining Residual Stresses

2011 ◽  
Vol 133 (2) ◽  
Author(s):  
A. Makino ◽  
D. V. Nelson ◽  
M. R. Hill
Keyword(s):  
Residual Stresses ◽  
Small Diameter ◽  
Small Hole ◽  
Hole Drilling ◽  
New Approach ◽  
Hole Drilling Method ◽  
Diameter Hole ◽  
Surface Displacements ◽  
Drilling Method ◽  
Fresh Surface

The strain gauge rosette hole drilling method is often used for determining residual stresses versus depth to depths on the order of 0.5–1.5 mm. Frequently, it is of interest to find stress profiles to greater depths. To provide such a capability, a new approach is presented. Residual stresses versus depth are found by drilling a small diameter hole incrementally to a depth of half of its diameter. The profile of stresses versus depth is found from changes in surface displacements associated with the stress relief from introducing the hole, observed by optical means. Next, a larger diameter, square-bottomed hole is milled directly over the small hole to a depth equaling that of the smaller diameter hole. The bottom of the larger hole provides a fresh surface for optical observation and incremental drilling of a new small hole. This procedure is repeated until a desired total depth is reached. A computational approach is described for correcting the stresses found from the small holes to account for the perturbation of stresses by the material removed by the larger diameter hole. Results of applying this method to find stresses versus depth in a plate subject to uniaxial bending stress and a plate with biaxial residual stresses that vary from compression to tension through the thickness are shown.

Measurement of Residual Stresses Near the Surface Using the Crack Compliance Method

1991 ◽  
Vol 113 (2) ◽  
pp. 199-204 ◽  
Author(s):  
W. Cheng ◽  
I. Finnie ◽  
O¨. Vardar
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Computational Model ◽  
Strain Measurement ◽  
Stress Measurement ◽  
Residual Stress Measurement ◽  
Hole Drilling ◽  
Hole Drilling Method ◽  
Drilling Method

The use of thin cuts for residual stress measurement is referred to as the crack compliance method. A computational model is presented for the determination of normal and shear residual stresses near the surface by introducing shallow cuts. The optimum regions for strain measurement are obtained. This method is shown to be considerably more sensitive than the conventional hole drilling method and is capable of measuring residual stresses which vary with depth below the surface.

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