scholarly journals Analysis of the Influence of the Thickness and the Hole Radius on the Calibration Coefficients in the Hole-Drilling Method for the Determination of Non-uniform Residual Stresses

2018 ◽  
Vol 59 (1) ◽  
pp. 79-94 ◽  
Author(s):  
J. M. Alegre ◽  
A. Díaz ◽  
I. I. Cuesta ◽  
J. M. Manso

2015 ◽  
Vol 732 ◽  
pp. 28-31 ◽  
Author(s):  
František Trebuňa ◽  
František Šimčák ◽  
Miroslav Pástor ◽  
Patrik Šarga

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.



Author(s):  
Xuan Zhu ◽  
Francesco Lanza di Scalea ◽  
Mahmood Fateh

Continuous Welded Rail (CWR) has been widely used in modern railway system for it provides smooth ride, higher freight speed, and less maintenance. A major safety concern with this type of structure is the absence of the expansion joints and the potential of buckling in hot weather. According to the FRA safety statistics, the track alignment irregularity is one of the leading factors responsible for the accidents and the most economic/environmental damages, among all the railway accident causes. However, the thermal stress measurement in the CWR for buckling prevention has been an unresolved problem in railroad maintenance. In this study, a method is introduced to determine the in-situ thermal stress of the in-service CWR by using the Hole-Drilling method. The ASTM Hole-Drilling test procedure, as one type of stress relaxation methods, was originally developed to measure the in-plane residual stresses close to the specimen surfaces. The residual stresses are typically computed based on the relieved strains with the calibration coefficients. Inspired by the stress relaxation philosophy, an investigation on the thermal stress measurement of the CWR using the Hole-Drilling test procedure is conducted in this paper. First, the feasibility of using the Hole-Drilling method of the thermal stress measurement is examined via a 3-D finite element model. The stress relaxation computed from the Hole-Drilling test is compared with the applied uniaxial thermal stress. To facilitate the implementation on the CWR, a new set of calibration coefficients with finer depth increment is computed with a novel three-dimensional finite element model for more realistic simulation. The updated coefficients are experimentally validated with an aluminum column specimen under uniaxial load. For the experimental studies, a roadside prototype is developed and two sets of tests are carried out on free-to-expand rail tracks and on rails subjected to controlled thermal loads at UCSD Powell Laboratories. The relieved stresses are computed using the updated calibration coefficients, and a linear relationship between the axial and vertical residual stresses at the neutral axis is observed for both 136RE and 141RE rails. Furthermore, the in-situ thermal stresses are estimated with the residual stress compensation and the neutral temperatures are predicted according to linear thermal expansion theory. These tests illustrate that the determination of the thermal stresses by the Hole-Drilling method is in principle possible, once ways are developed to compensate for the residual stress relaxation. One such compensation is proposed in this paper. A statistical interpretation on the proposed method is also given to provide a reference for railroad applications.





1991 ◽  
Vol 113 (2) ◽  
pp. 199-204 ◽  
Author(s):  
W. Cheng ◽  
I. Finnie ◽  
O¨. Vardar

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.



2003 ◽  
Vol 43 (1) ◽  
pp. 97-104 ◽  
Author(s):  
G. Focht ◽  
K. Schiffner


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