A procedure for high residual stresses measurement using the ring-core method

Strain ◽  
2018 ◽  
Vol 54 (4) ◽  
pp. e12270 ◽  
Author(s):  
R. Moharrami ◽  
M. Sadri
Keyword(s):  
Residual Stresses ◽  
Core Method ◽  
Ring Core

Verification of the Geometric Parameters of the Ring-Core Method

2016 ◽  
Vol 827 ◽  
pp. 109-112
Author(s):  
Patrik Šarga ◽  
František Menda ◽  
František Trebuňa
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Complex Analysis ◽  
Geometric Parameters ◽  
Stress Determination ◽  
Residual Stress Determination ◽  
Material Thickness ◽  
Core Method ◽  
Stress Components ◽  
Ring Core

The Ring-Core method is a semi-destructive method for residual stress determination inside materials. The evaluation of residual stresses using Ring-Core method requires complex analysis of the geometric parameters. This work deals with the uniformly distributed residual stress components through the material thickness.

Effect of the Kinematic Hardening in the Simulations of the Straightening of Long Rolled Profiles

2014 ◽  
Vol 611-612 ◽  
pp. 178-185 ◽  
Author(s):  
Chantal Bouffioux ◽  
Romain Boman ◽  
Nicolas Caillet ◽  
Nicolas Rich ◽  
Jean Philippe Ponthot ◽  
...  
Keyword(s):  
Residual Stresses ◽  
Inverse Method ◽  
Kinematic Hardening ◽  
Material Behavior ◽  
The Finite Element Method ◽  
The Real ◽  
Core Method ◽  
Hot Rolled ◽  
The Impact ◽  
Ring Core

Residual stresses and lack of straightness appear during the cooling of sheet piles where the initial temperature field is not homogeneous. To meet the standards, the long hot rolled pieces are straightened using a series of rollers placed alternately above and below the pieces with shifts which create a succession of bendings. The process is modeled to study the impact of the industrial parameters (the duration of the cooling and the rollers positions), to improve the final geometry and to reduce the residual stresses. Tests are carried out on this structural steel to observe the material behavior, then material laws are chosen and the parameters of these laws are defined using an inverse method. Two sets of material data are obtained: for the first one, the hardening is supposed to be isotropic, and for the second one, additional tests are performed to describe isotropic and kinematic hardenings. The cooling followed by the straightening is then simulated by the finite element method with these two sets of data. The comparison of the rollers forces, the deformation and the residual stresses show the impact of the kinematic hardening on such a process where the material undergoes a succession of tensions and compressions. The real forces applied by the rollers, the real curvature of the interlocks at the end of the straightening process and the distribution of the residual longitudinal stresses measured on the web using the ring core method are used to validate the numerical model.

scholarly journals DESIGN OF CONTROL FOR THE DEVICE USING FOR THE DETERMINATION OF RESIDUAL STRESSES BY RING-CORE METHOD

2018 ◽  
pp. 162-168
Author(s):  
Šarga Patrik ◽  
Trebuňa František ◽  
Grejták Branislav
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Strain Gauge ◽  
Programmable Logic Controller ◽  
Experimental Methods ◽  
Programmable Logic ◽  
Measuring Device ◽  
Core Method ◽  
Ring Core ◽  
Original Device

Urgency of the research. Residual stresses in machine parts and constructions greatly affect their service life and reliability. They are introduced into the manufactured object at each production process and their level can change significantly due to the operation of the product. Their main risk lies in the fact that they add up to the external load and can be the cause of the failure of the construction. Residual stresses can not be determined by simulation methods. They can only be determined using experimental methods. One of these method is the Ring-Core method, the principle of which is to form an annular groove around the strain gauge. Creating of annular groove releases the internal stresses, which can be recorded by a strain gauge. The quality of the formed groove has a significant impact on the overall results of residual stress determination, so it is important to make it as accurate as possible. For this reason, it is necessary to have the most reliable device to form an annular groove. Target setting. Our goal was to design the drive and control for the measuring device for milling the annular groove. This will make it possible to mill the annular groove more precisely, and the resulting residual stresses will be minimally affected by the inaccuracy of the groove. Actual scientific researches and issues analysis. When designing the control of the device and preparing this paper, we took into account not only current sources – publications and papers dealing with the current state of existing measuring devices used for determining residual stresses by Ring-Core method, but – we also took into account our practical experience gained in numerous residual stress determinations by experimental methods. Uninvestigated parts of general matters defining. A modified device requires thorough testing, which has not been implemented during the research for this paper. The research objective. The goal of the research was to create a control for the existing mechanical measuring device used for creating annular groove for determining residual stresses by Ring-Core method. The statement of basic materials. The original mechanical device was supplemented by actuators, which were designed to automate the movement in horizontal axes as well as in the vertical axis. Thanks to this, we have achieved greater precision when positioning the work tool above the center of the strain gauge. At the same time, the original equipment was completed with a servo motor that serves to drive the cutter. For all these elements, control by Programmable Logic Controller was proposed. Conclusions. Our task was to design control for the original device used for residual stress measurement by the RingCore method. We needed to design drives to automate the device. For our needs, we decided to apply linear actuators selected according to the requested criteria. After designing of the electric drives and modifying of the original device, we proceeded to implement control by Programmable Logic Controller. After that, we created a control program in the Automation studio software. This modified measuring device is able to achieve a much higher precision of the annular groove milling, which makes it possible to deter-mine the residual stresses in the structures more precisely

scholarly journals Evaluation of Residual Stresses using Ring Core Method

2010 ◽  
Vol 6 ◽  
pp. 44004 ◽  
Author(s):  
J. Václavík ◽  
O. Weinberg ◽  
P. Bohdan ◽  
J. Jankovec ◽  
S. Holý
Keyword(s):  
Residual Stresses ◽  
Core Method ◽  
Ring Core

scholarly journals Applications of the Strain Gauge for Determination of Residual Stresses using Ring-core Method

2012 ◽  
Vol 48 ◽  
pp. 396-401 ◽  
Author(s):  
Kristína Masláková ◽  
František Trebuňa ◽  
Peter Frankovský ◽  
Michal Binda
Keyword(s):  
Residual Stresses ◽  
Strain Gauge ◽  
Core Method ◽  
Ring Core

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.

scholarly journals Intragranular Residual Stress Evaluation Using the Semi-Destructive FIB-DIC Ring-Core Drilling Method

2014 ◽  
Vol 996 ◽  
pp. 8-13 ◽  
Author(s):  
Alexander J.G. Lunt ◽  
Alexander M. Korsunsky
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Titanium Aluminide ◽  
Ion Beam ◽  
Sample Surface ◽  
Image Correlation ◽  
Near Surface ◽  
Core Drilling ◽  
Drilling Method ◽  
Ring Core

Titanium aluminide (TiAl) is a lightweight intermetallic compound with a range of exceptional mid-to-high temperature mechanical properties. These characteristics have the potential to deliver significant weight savings in aero engine components. However, the relatively low ductility of TiAl requires improved understanding of the relationship between manufacturing processes and residual stresses in order to expand the use of such components in service. Previous studies have suggested that stress determination at high spatial resolution is necessary to achieve better insight. The present paper reports progress beyond the current state-of-the-art towards the identification of the near-surface intragranular residual stress state in cast and ground TiAl at a resolution better than 5μm. The semi-destructive ring-core drilling method using Focused Ion Beam (FIB) and Digital Image Correlation (DIC) was used for in-plane residual stress estimation in ten grains at the sample surface. The nature of the locally observed strain reliefs suggests that tensile residual stresses may have been induced in some grains by the unidirectional grinding process applied to the surface.

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