Influence of Near-Surface Residual Stresses on Strength of Ceramics

2002 ◽  
pp. 125-133
Author(s):  
T. Fett ◽  
D. Munz
Keyword(s):  
Residual Stresses ◽  
Near Surface ◽  
Surface Residual Stresses

The Compliance Method for Measurement of Near Surface Residual Stresses—Analytical Background

1994 ◽  
Vol 116 (4) ◽  
pp. 550-555 ◽  
Author(s):  
M. Gremaud ◽  
W. Cheng ◽  
I. Finnie ◽  
M. B. Prime
Keyword(s):  
Numerical Simulation ◽  
Residual Stresses ◽  
Random Errors ◽  
Residual Stress Field ◽  
Near Surface ◽  
Surface Residual Stresses ◽  
Zero Shift ◽  
Stress States ◽  
The Stability ◽  
Piecewise Functions

Introducing a thin cut from the surface of a part containing residual stresses produces a change in strain on the surface. When the strains are measured as a function of the depth of the cut, residual stresses near the surface can be estimated using the compliance method. In previous work, the unknown residual stress field was represented by a series of continuous polynomials. The present paper shows that for stress states with steep gradients, superior predictions are obtained by using “overlapping piecewise functions” to represent the stresses. The stability of the method under the influence of random errors and a zero shift is demonstrated by numerical simulation.

Measurement of Near Surface Residual Stresses Using Electric Discharge Wire Machining

1994 ◽  
Vol 116 (1) ◽  
pp. 1-7 ◽  
Author(s):  
W. Cheng ◽  
I. Finnie ◽  
M. Gremaud ◽  
M. B. Prime
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Electric Discharge ◽  
Theoretical Approach ◽  
Stress Measurement ◽  
Stress Gradient ◽  
Experimental Results ◽  
Residual Stress Measurement ◽  
Near Surface ◽  
Surface Residual Stresses

In previous work it has been shown that near surface residual stresses may be deduced from surface strains produced by making a cut of progressively increasing depth. The process of electric discharge wire machining (EDWM), by providing very narrow cuts, greatly improves the ability of the method to resolve a stress gradient near the surface. However, the EDWM process may also introduce residual stresses. In the present work a model for estimating the influence of EDWM is presented, and a procedure for eliminating its effect on residual stress measurement is developed. Experimental results validate the theoretical approach.

scholarly journals Neutron Diffraction Evaluation of Near Surface Residual Stresses at Welds in 1300 MPa Yield Strength Steel

Materials ◽  
2017 ◽  
Vol 10 (6) ◽  
pp. 593 ◽  
Author(s):  
Ebrahim Harati ◽  
Leif Karlsson ◽  
Lars-Erik Svensson ◽  
Thilo Pirling ◽  
Kamellia Dalaei
Keyword(s):  
Neutron Diffraction ◽  
Yield Strength ◽  
Residual Stresses ◽  
Near Surface ◽  
Surface Residual Stresses

The Compliance Method for Measurement of Near Surface Residual Stresses—Application and Validation for Surface Treatment by Laser and Shot-Peening

1994 ◽  
Vol 116 (4) ◽  
pp. 556-560 ◽  
Author(s):  
W. Cheng ◽  
I. Finnie ◽  
M. Gremaud ◽  
A. Rosselet ◽  
R. D. Streit
Keyword(s):  
Residual Stresses ◽  
Surface Treatment ◽  
Hole Drilling ◽  
Ray Method ◽  
Near Surface ◽  
X Ray ◽  
Advantages And Disadvantages ◽  
Surface Residual Stresses ◽  
Ray Methods ◽  
Good Agreement

Residual stresses due to surface treatment are measured using the compliance method. The method makes use of the strains measured on the surface while a cut is extended progressively along a plane of interest. The experimental results for a shot peened specimen show good agreement with those obtained by the X-ray method. This experiment demonstrates that the compliance method is accurate and capable of measuring residual stresses which vary rapidly over a depth of less than 50 μm. Good general agreement with results by the X-ray method is also obtained for a laser treated specimen. Some advantages and disadvantages of the present method relative to hole-drilling, layer removal and X-ray methods are discussed.

X-ray Measurements of Surface Residual Stresses in Cold Rolled α-Brass

1970 ◽  
Vol 14 ◽  
pp. 389-407 ◽  
Author(s):  
W. Wallace ◽  
T. Terada
Keyword(s):  
Residual Stresses ◽  
Lattice Parameter ◽  
Rolled Sheet ◽  
Near Surface ◽  
X Ray ◽  
Elastic Stresses ◽  
Surface Residual Stresses ◽  
Exposure Method ◽  
Cold Rolled ◽  
Anisotropic Elastic

AbstractResidual elastic stresses have been measured in cold rolled α-brass (30% zinc) using the available x-ray diffractometer methods. Residual stress values obtained by the two exposure and sin2ψ methods of stress analysis are compared with data obtained using Wagner's extrapolation method.For deformations up to 50% reduction in thickness, tensile surface stresses prevailed, and in most cases could be detected by these methods. Uncertainty of the value of a0, the lattice parameter of the deformed' material, presents a serious limitation to the extrapolation technique. Using the approximation a0 = a0ann, residual stresses appear lower than, and frequently of opposite sign to those given by the two exposure method. In addition, lattice parameter variations in the near surface regions of the rolled sheet were opposite to those expected from the true macrostress distributions shown to exist by the two exposure method and by strain gauge techniques. The distributions of ahkl points in the extrapolation plots were in agreement with theory for a combination of anisotropic elastic stresses and low stacking fault density.

Correlation between pre- and post-treatments of additively manufactured 316L parts and the resulting low cycle fatigue behavior

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Kai-Uwe Garthe ◽  
Kay-Peter Hoyer ◽  
Leif Hagen ◽  
Wolfgang Tillmann ◽  
Mirko Schaper
Keyword(s):  
Surface Roughness ◽  
Residual Stresses ◽  
Low Cycle Fatigue ◽  
Fatigue Behavior ◽  
Atmospheric Plasma ◽  
Alumina Coating ◽  
Cycle Fatigue ◽  
Near Surface ◽  
Content Type ◽  
Surface Residual Stresses

Purpose The currently existing restrictions regarding the deployment of additively manufactured components because of poor surface roughness, porosity and residual stresses as well as their influence on the low-cycle fatigue (LCF) strength are addressed in this paper. Design/methodology/approach This study aims to evaluating the effect of different pre- and post-treatments on the LCF strength of additively manufactured 316L parts. Therefore, 316L specimens manufactured by laser powder bed fusion were examined in their as-built state as well as after grinding, or coating with regard to the surface roughness, residual stresses and LCF strength. To differentiate between topographical effects and residual stress-related phenomena, stress-relieved 316L specimens served as a reference throughout the investigations. To enable an alumina coating of the 316L components, atmospheric plasma spraying was used, and the near-surface residual stresses and the surface roughness are measured and investigated. Findings The results have shown that the applied pre- and post-treatments such as stress-relief heat treatment, grinding and alumina coating have each led to an increase in LCF strength of the 316L specimens. In contrast, the non-heat-treated specimens predominantly exhibited coating delamination. Originality/value To the best of the authors’ knowledge, this is the first study of the correlation between the LCF behavior of additively manufactured uncoated 316L specimens in comparison with additively manufactured 316L specimens with an alumina coating.

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