An Axisymmetric Stress Release Method for Measuring the Autofrettage Level in Thick-Walled Cylinders—Part II: Experimental Validation

1994 ◽  
Vol 116 (4) ◽  
pp. 389-395 ◽  
Author(s):  
M. Perl ◽  
R. Arone´
Keyword(s):  
Numerical Simulation ◽  
Cost Effective ◽  
Preliminary Test ◽  
Residual Stress Field ◽  
Minimum Thickness ◽  
Experimental Procedure ◽  
Gun Barrel ◽  
Quantitative Monitoring ◽  
Release Method ◽  
Gradual Release

The basic concept of a new experimental method for measuring the level of autofrettage in thick-walled cylinders as well as a comprehensive numerical simulation were presented in Part I of this paper. A pilot test is conducted herein on a 105-mm autofrettage gun barrel to validate the proposed procedure. First, a preliminary test is performed to determine the minimum thickness required for a ring, cut from the barrel, in order to be a representative, valid, and free of edge-effect specimen. Then, the main experiment is conducted consisting of the gradual release of the residual stress field due to autofrettage prevailing in the ring specimen. An array of seven equally spaced, identical, radial notches is progressively cut at the inner surface of the ring, while the released hoop stress is continuously measured by a strain gage-based computerized data acquisition system. The process is accomplished by a detailed numerical simulation enabling a qualitative and quantitative monitoring of the procedure. The proposed experimental procedure is found to be feasible, reliable, and cost-effective, and to yield accurate results.

An Axisymmetric Stress Release Method for Measuring the Autofrettage Level in Thick-Walled Cylinders—Part I: Basic Concept and Numerical Simulation

1994 ◽  
Vol 116 (4) ◽  
pp. 384-388 ◽  
Author(s):  
M. Perl ◽  
R. Arone´
Keyword(s):  
Empirical Relation ◽  
Pilot Test ◽  
Stress Release ◽  
Residual Stress Field ◽  
Hoop Strain ◽  
Experimental Procedure ◽  
Strain Measurements ◽  
Gun Barrel ◽  
Element Simulation ◽  
Release Method

A new experimental method for measuring the level of autofrettage in thick-walled cylinders is suggested. The method is based on measuring the hoop-strain while axisymmetrically releasing the residual stress field prevailing in the cylinder’s wall. A parametric study of the proposed experimental procedure conducted by a finite element simulation yields a simple empirical relation, which readily enables determining the actual autofrettage level from the strain measurements. This relation is found to be practically unique for all relevant cases, i.e., cylinders with radii ratios of b/a=1.6÷2.2 and autofrettage percents of φ=50–100 percent. A pilot test conducted on a 105-mm autofrettaged gun barrel, which experimentally validates the proposed procedure, is presented in Part II (Perl and Arone, 1994) of this paper.

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.

Selecting Material Properties for Maximizing Gun Firing Power

2014 ◽  
Author(s):  
J. Perry ◽  
M. Perl
Keyword(s):  
Detailed Analysis ◽  
Yield Stress ◽  
Bauschinger Effect ◽  
Strain Curve ◽  
Residual Stress Field ◽  
Transition Range ◽  
Effect Factor ◽  
Gun Barrel ◽  
Zero Offset ◽  
Gun Firing

The design of gun barrels aims at maximizing its firing power determined by its SMP — the maximal allowed firing pressure, which is considerably enhanced by inducing a favorable residual stress field through the barrel’s wall commonly by the autofrettage process. Presently, there are two distinct processes: hydrostatic and swage autofrettage. In both processes the barrel’s material is fully or partially plastically deformed. Recently, a 3-D code was developed, which finally enables a realistic simulation of both swage and hydraulic autofrettage, using the experimentally measured stress-strain curve, and incorporating the Bauschinger effect. This code enables a detailed analysis of all the factors involving the final SMP of a barrel, and it can be used to establish the optimal process for any gun barrel design. A major outcome of this analysis was the fact that the SMP of an autofrettaged barrel is dictated by the detailed plastic characteristics on the barrel’s material. The main five plastic parameters of the material that have been identified are: the exact (zero offset) value of the yield stress, the universal plastic curve in tension and in compression, the Bauschinger Effect Factor (BEF) curve, and the Elastic-Plastic Transition Range (EPTR). A detailed analysis of these three materials points to the fact that the major parameter determining the barrel’s SMP is the yield stress of the material and that the best way to determine it is by the newly developed “zero offset” method. All these four parameters have a greater influence on the SMP of an hydraulically autofrettaged barrel than on a swaged one.

Numerical Simulation of Residual Stress Field Induced in Round Rod Part Affected by Laser Parameters

2016 ◽  
Vol 43 (8) ◽  
pp. 0802007
Author(s):  
汪静雪 Wang Jingxue ◽  
章艳 Zhang Yan ◽  
张兴权 Zhang Xingquan ◽  
戚晓利 Qi Xiaoli ◽  
裴善报 Pei Shanbao ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Residual Stress ◽  
Stress Field ◽  
Residual Stress Field ◽  
Laser Parameters

Elasto-Plastic Stresses in Thick Walled Cylinders

2003 ◽  
Vol 125 (3) ◽  
pp. 248-252 ◽  
Author(s):  
Joseph Perry ◽  
Jacob Aboudi
Keyword(s):  
Residual Stress ◽  
Yield Criterion ◽  
Plastic Region ◽  
Weight Ratio ◽  
Theoretical Development ◽  
Cylinder Wall ◽  
Residual Stress Field ◽  
Gun Barrel ◽  
Von Mises ◽  
Made In

In the optimal design of a modern gun barrel, there are two main objectives to be achieved: increasing its strength-weight ratio and extending its fatigue life. This can be carried out by generating a residual stress field in the barrel wall, a process known as autofrettage. It is often necessary to machine the autofrettaged cylinder to its final configuration, an operation that will remove some of the desired residual stresses. In order to achieve a residual stress distribution which is as close as possible to the practical one, the following assumptions have been made in the present research on barrel analysis: A von Mises yield criterion, isotropic strain hardening in the plastic region in conjunction with the Prandtl-Reuss theory, pressure release taking into consideration the Bauschinger effect and plane stress conditions. The stresses are calculated incrementally by using the finite difference method, whereby the cylinder wall is divided into N-rings at a distance Δr apart. Machining is simulated by removing rings from both sides of the cylindrical surfaces bringing the cylinder to its final shape. After a theoretical development of the procedure and writing a suitable computer program, calculations were performed and a good correlation with the experimental results was found. The numerical results were also compared with other analytical and experimental solutions and a very good correlation in shape and magnitude has been obtained.

The Influence of the Bauschinger Effect on the Yield Stress, Young’s Modulus, and Poisson’s Ratio of a Gun Barrel Steel

2005 ◽  
Vol 128 (2) ◽  
pp. 179-184 ◽  
Author(s):  
J. Perry ◽  
M. Perl ◽  
R. Shneck ◽  
S. Haroush
Keyword(s):  
Plastic Deformation ◽  
Yield Stress ◽  
Young’S Modulus ◽  
Poisson’S Ratio ◽  
Bauschinger Effect ◽  
Young's Modulus ◽  
Poisson's Ratio ◽  
Compression Tests ◽  
Residual Stress Field ◽  
Gun Barrel

The Bauschinger effect (BE) was originally defined as the phenomenon whereby plastic deformation causes a loss of yield strength restraining in the opposite direction. The Bauschinger effect factor (BEF), defined as the ratio of the yield stress on reverse loading to the initial yield stress, is a measure of the magnitude of the BE. The aim of the present work is to quantitatively evaluate the influence of plastic deformation on other material properties such as Young’s modulus and Poisson’s ratio for gun barrel steel, thus extending the definition of the Bauschinger effect. In order to investigate the change in this material’s properties resulting from plastic deformation, several uniaxial tension and compression tests were performed. The yield stress and Young’s modulus were found to be strongly affected by plastic strain, while Poisson’s ratio was not affected at all. An additional result of these tests is an exact zero offset yield point definition enabling a simple evaluation of the BEF. A simple, triphase test sufficient to characterize the entire elastoplastic behavior is suggested. The obtained experimental information is readily useful for autofrettage residual stress field calculations.

Numerical Simulation of Residual Stress Field Induced by Water-Jet Cavitation Peening

2013 ◽  
Vol 345 ◽  
pp. 312-315 ◽  
Author(s):  
Bing Han ◽  
Yan Hua Wang ◽  
Chang Liang Xu
Keyword(s):  
Numerical Simulation ◽  
Residual Stress ◽  
Stress Field ◽  
New Technology ◽  
Diffraction Method ◽  
Spring Steel ◽  
Water Jet ◽  
Material Surface ◽  
Residual Stress Field ◽  
Element Analysis

Water-jet cavitation peening is a new technology for surface modification of metallic materials. Compress residual stress layer is induced by impact wave pressure in the submerged cavitating jets processing. Based on ANSYS/LS-DYNA finite element analysis software, residual stress field in the SAE1070 spring steel material surface induced by cavitate-jet water peening process is simulated, the magnitude and variation rules of the residual stress along the layer depth under different conditions is obtained. In order to verify the correctness of the numerical simulation, the size and distribution of residual stress by the X-ray diffraction method. The results show that the numerical simulation and experimental results are well consistent.

Numerical Simulation of Residual Stresses Induced from Shot Peening with Finite Element Method

2013 ◽  
Vol 433-435 ◽  
pp. 1898-1901
Author(s):  
Li Juan Cao ◽  
Shou Ju Li ◽  
Zi Chang Shangguan
Keyword(s):  
Numerical Simulation ◽  
Finite Element Method ◽  
Residual Stress ◽  
Surface Layer ◽  
Residual Stresses ◽  
Shot Peening ◽  
Target Material ◽  
Residual Stress Field ◽  
State Of Stress ◽  
Compressive Residual Stresses

Shot peening is a manufacturing process intended to give components the final shape and to introduce a compressive residual state of stress inside the material in order to increase fatigue life. The modeling and simulation of the residual stress field resulting from the shot peening process are proposed. The behaviour of the peened target material is supposed to be elastic plastic with bilinear characteristics. The results demonstrated the surface layer affected by compressive residual stresses is very thin and the peak is located on the surface.

Assessment of the Crack Compliance Method and the Introduction of Residual Stresses by Shot Peening Using the Finite Element Method

2009 ◽  
Vol 15 ◽  
pp. 109-114 ◽  
Author(s):  
G. Urriolagoitia-Sosa ◽  
E. Zaldivar-González ◽  
J.M. Sandoval Pineda ◽  
J. García-Lira
Keyword(s):  
Numerical Simulation ◽  
Residual Stress ◽  
Stress Field ◽  
Residual Stresses ◽  
Shot Peening ◽  
Working Life ◽  
The Finite Element Method ◽  
Residual Stress Field ◽  
Main Effect

The interest on the application of the shot peening process to arrest and/or delay crack growth is rising. The main effect of the shot peening technique is to introduce a residual stress field that increases the working life of mechanical components. In this paper, it is presented the numerical simulation (FEM) of the shot peening process and the effect of introducing a residual stress field. Besides, the consequence of changing the sizes of the impacting ball is analyzed. This work also used the Crack Compliance Method (CCM) for the determination of residual stresses in beams subjected to a numerical simulation of a shot peening process. The numerical results obtained provide a quantitative demonstration of the effect of shot peening on the introduction of residual stresses by using different sizes of impacting balls and assess the efficiency of the CCM.

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