Determination of the Necessary Geometric Parameters of the Specimen in Ring-Core Method

2013 ◽  
Vol 486 ◽  
pp. 90-95 ◽  
Author(s):  
František Menda ◽  
František Trebuňa ◽  
Patrik Šarga
Keyword(s):  
Residual Stress ◽  
Influential Factors ◽  
Hole Drilling ◽  
Hole Drilling Method ◽  
Incremental Method ◽  
Core Method ◽  
Measuring Techniques ◽  
Drilling Method ◽  
Non Destructive ◽  
Ring Core

There are several measuring techniques for determining residual stress which can be divided according to the created damage in to the construction in non-destructive, semi-destructive and destructive ones. One of the most common is semi-destructive hole-drilling method. This paper deals about Ring-Core method which is based on the similar principles. Today, there is no standard for the Ring-Core method, thus it is important to consider various influential factors. One of them are the dimensions of specimen. Calibration coefficients are determined by finite element (FE) analysis using the commercial software Solidworks. These coefficients are used for residual stress evaluation by incremental method used in Ring-Core method. The influence of different specimen dimensions on the accuracy of the evaluated residual stresses is considered.

scholarly journals Estimation of Residual Stress Field Uniformity when Using the Ring-Core Method

2014 ◽  
Vol 996 ◽  
pp. 325-330 ◽  
Author(s):  
František Menda ◽  
Patrik Šarga ◽  
František Trebuňa
Keyword(s):  
Complex Analysis ◽  
Hole Drilling ◽  
Data Sets ◽  
Residual Stress Field ◽  
Hole Drilling Method ◽  
Core Method ◽  
Uniformity Test ◽  
Drilling Method ◽  
Field Uniformity ◽  
Ring Core

The evaluation of residual stresses using Ring-Core method requires complex analysis of the acquired strain values. The development is based on ASTM Standard E837-08 for hole-drilling method, but the specific approach for Ring-Core is needed. The input data sets obtained from strain gage rosette are categorized by proposed uniformity test. The influence of geometric parameters of the specimen on this test and subsequently on the both uniform and nonuniform calculations is considered.

Hole-Drilling Method for Residual Stress Measurement - Consideration of Elastic-Plastic Material Properties

2013 ◽  
Vol 768-769 ◽  
pp. 174-181 ◽  
Author(s):  
David von Mirbach
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Yield Stress ◽  
Material Properties ◽  
Plastic Material ◽  
Hole Drilling ◽  
Hole Drilling Method ◽  
Drilling Method ◽  
Elastic Plastic Material ◽  
Ring Core

Two commonly used mechanical methods for the determination of residual stresses are the hole-drilling method and the ring-core method, which can be regarded as semi-destructive. The most restricting limitation for the general applicability of both methods, according to the current state of science and technology, is the fact that the scope for relatively low residual stress under 60% of the yield stress is limited.This is a result of the notch effect of the hole or ring core, which leads to a plastification around and on the bottom of the hole and ring shaped groove already at stresses well below the yield stress of the material. The elastic evaluation of the resulting plastic strains leads consequently to an overestimation of the delineated residual stresses. In this paper the influence of elastic-plastic material properties no the specific calibration function for the hole-drilling method using the differential method is studied, and the method of adaptive calibration functions is presented.

scholarly journals Four-Point Bending Tests to Study the So-Called Plasticity Effect on the Residual Stress Results Determined by the Hole-Drilling and Ring-Core Methods

2014 ◽  
Vol 996 ◽  
pp. 319-324
Author(s):  
David von Mirbach
Keyword(s):  
Residual Stress ◽  
Bending Test ◽  
Hole Drilling ◽  
Test Machine ◽  
Bending Tests ◽  
Hole Drilling Method ◽  
Four Point Bending ◽  
Drilling Method ◽  
Four Point Bending Test ◽  
Ring Core

The hole-drilling method (HDM) and ring core method (RCM) are limited to low residual stresses under 60% of the yield stress. This issue will experimentally analyze the method of adaptive calculation function, presented by the author on the ICRS9. With a four-point-bending test machine, a defined stress can be triggered between the middle bending. In this defined loading area, the strains in two load cases with the HDM and the RCM configuration were measured. With these measured strains the residual stress calculation will be analysed.

Analysis of Differential Method Used for the Evaluation of Uniform Residual Stresses by the Ring-Core Method

2015 ◽  
Vol 732 ◽  
pp. 20-23
Author(s):  
Patrik Šarga ◽  
František Menda ◽  
František Trebuňa ◽  
Ladislav Kováč
Keyword(s):  
Differential Method ◽  
Hole Drilling ◽  
Full Potential ◽  
Easy Method ◽  
Stress Evaluation ◽  
Hole Drilling Method ◽  
Core Method ◽  
Drilling Method ◽  
Recent Developments ◽  
Ring Core

Despite the significant advantages of the Ring-Core method over the hole-drilling method, the Ring-Core method is still less common. Recent developments at our department showed the full potential of the method when using the adequate calibration coefficients. In this paper the differential method, a quick and easy method for uniform residual stress evaluation is described and the influence of its relaxation coefficients on the specimen’s dimensions is obtained.

Residual Stress Prediction Using Neural Network Approach

2014 ◽  
Vol 611 ◽  
pp. 436-440 ◽  
Author(s):  
František Menda ◽  
Marcel More ◽  
G.P. Cardona-Cuervo ◽  
F.J. Martinez-Tabares
Keyword(s):  
Neural Network ◽  
Residual Stress ◽  
Hole Drilling ◽  
Neural Network Approach ◽  
Stress Evaluation ◽  
New Approach ◽  
Hole Drilling Method ◽  
Drilling Method ◽  
Stress Prediction ◽  
Ring Core

Procedures for residual stress evaluation by using Ring-Core method have not been standardized. Most common techniques are derived from the ones used for similar semi-destructive hole-drilling method. The differences between research approaches can cause significant errors. New approach using neural network is proposed as a more adaptive way for residual stress evaluation than the commonly used methods.

Residual Stress Measurements in an Autofrettage Tube Using Hole Drilling Method

2012 ◽  
Vol 134 (5) ◽  
Author(s):  
Hamid Jahed ◽  
Mohammad Reza Faritus ◽  
Zeinab Jahed
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Hoop Stress ◽  
Test Method ◽  
Test Material ◽  
Hole Drilling ◽  
Hole Drilling Method ◽  
Ring Sample ◽  
Drilling Method ◽  
American Society

Relieved strains due to drilling hole in a ring sample cut from an autofrettage cylinder are measured. Measured strains are then transformed to residual stresses using calibration constants and mathematical relations of elasticity based on ASTM standard recommendations (American Society for Testing and Materials, ASTM E 837-08, 2008, “Standard Test Method for Determining Residual Stresses by the Hole-Drilling Strain-Gage Method,” American Society for Testing and Materials). The hydraulic autofrettage is pressurizing a closed-end long cylinder beyond its elastic limits and subsequently removing the pressure. In contrast to three-dimensional stress state in the autofrettage tube, the stress measurement in hole drilling method is performed on a traction free surface formed from cutting the ring sample. The process of cutting the ring sample from a long autofrettaged tube is simulated using finite element method (FEM) and the redistribution of the residual stress due to the cut is discussed. Hence, transformation of the hole drilling measurements on the ring slice to the autofrettage residual stresses is revealed. The residual stresses are also predicted by variable material properties (VMP) method (Jahed, H., and Dubey, R. N., 1997, “An Axisymmetric Method of Elastic-Plastic Analysis Capable of Predicting Residual Stress Field,” Trans. ASME J. Pressure Vessel Technol., 119, pp. 264–273) using real loading and unloading behavior of the test material. Prediction results for residual hoop stress agree very well with the measurements. However, radial stress predictions are less than measured values particularly in the middle of the ring. To remove the discrepancy in radial residual stresses, the measured residual hoop stress that shows a self-balanced distribution was taken as the basis for calculating residual radial stresses using field equations of elasticity. The obtained residual stresses were improved a lot and were in good agreement with the VMP solution.

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