Strength Evaluation and Fatigue Prediction of a Pressurized Thick-Walled Cylinder

2007 ◽  
Author(s):  
Omid Vakili ◽  
Zhong Hu ◽  
Fereidoon Delfanian
Keyword(s):  
Material Properties ◽  
Analytical Method ◽  
Thermal Damage ◽  
Liner Material ◽  
Proper Understanding ◽  
Gun Barrel ◽  
Subsequent Loss ◽  
Thick Cylinder ◽  
Pressurized Cylinder ◽  
Walled Cylinder

By design, a large caliber gun barrel routinely operates closer to its fatigue envelope than virtually any other device. The lifetime of a gun barrel is limited by bore damage and by fatigue crack growth, which depends crucially upon near-bore thermal damage arising from initial firing, the thermomechanical basis for early cracking and subsequent loss of liner material. The proper understanding and prediction of the strength and fatigue failure of a pressurized thick cylinder is an important prerequisite for any reliable application. In this paper, an analysis of two-dimensional stresses in a thick walled pressurized cylinder using an analytical method followed by fatigue calculation was performed. The effects of wall thickness and internal firing pressure, considering the material properties, on the stress distribution were investigated. This analytical method of stress analysis can be used as a valuable tool for evaluating strength and predicting failure phenomena of a large caliber gun barrel.

Crack Non-Circularity and Finite Erosion Effects on the 3D SIFs of a Bauschinger Modified Pressurized Thick-Walled Cylinder

2015 ◽  
Author(s):  
Qin Ma ◽  
Cesar Levy ◽  
Mordechai Perl
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Fatigue Life ◽  
Numerical Analysis ◽  
Material Properties ◽  
Thermal Loading ◽  
Circular Crack ◽  
Finite Element Package ◽  
Pressurized Cylinder ◽  
Walled Cylinder

Our previous studies have demonstrated that the 3D SIFs of a pressurized cylinder can be greatly affected by many factors. While an autofrettage process may introduce favorable residual stresses at the bore of the cylinder, other factors such as erosions and cracks, once introduced, may greatly reduce the effectiveness of the autofrettage results. In this study, we focus on how the non-circularity of cracks affects the 3D SIFs for a cylinder that contains finite erosions while keeping other conditions and material properties unchanged. Numerical analysis was performed using ANSYS, a standard commercially available finite element package. The residual stress due to any autofrettage process was simulated using the equivalent thermal loading. A closer look was given to problems with different crack configurations and how non-circularity of cracks affects the overall fatigue life of the cylinder when combined with other factors in comparison with circular crack only configurations.

Weight Functions for an External Longitudinal Semi-Elliptical Surface Crack in a Thick-Walled Cylinder

1997 ◽  
Vol 119 (1) ◽  
pp. 74-82 ◽  
Author(s):  
A. Kiciak ◽  
G. Glinka ◽  
D. J. Burns
Keyword(s):  
Stress Intensity ◽  
Stress Intensity Factors ◽  
Surface Crack ◽  
Complex Stress ◽  
Weight Functions ◽  
Stress Distributions ◽  
Intensity Factors ◽  
Reference Stress ◽  
Pressurized Cylinder ◽  
Walled Cylinder

Mode I weight functions were derived for the deepest and surface points of an external radial-longitudinal semi-elliptical surface crack in a thick-walled cylinder with the ratio of the internal radius to wall thickness, Ri/t = 1.0. Coefficients of a general weight function were found using the method of two reference stress intensity factors for two independent stress distributions, and from properties of weight functions. Stress intensity factors calculated using the weight functions were compared to the finite element data for several different stress distributions and to the boundary element method results for the Lame´ hoop stress in an internally pressurized cylinder. A comparison to the ASME Pressure Vessel Code method for deriving stress intensity factors was also made. The derived weight functions enable simple calculations of stress intensity factors for complex stress distributions.

Aspects of Experimental Errors and Data Reduction Schemes From Spherical Indentation of Isotropic Materials

2014 ◽  
Vol 136 (3) ◽  
Author(s):  
J. K. Phadikar ◽  
T. A. Bogetti ◽  
A. M. Karlsson
Keyword(s):  
Sensitivity Analysis ◽  
Experimental Investigation ◽  
Monte Carlo ◽  
Condition Number ◽  
Data Reduction ◽  
Material Properties ◽  
Analytical Method ◽  
Systematic Investigation ◽  
Spherical Indentation ◽  
Experimental Errors

Sensitivity to experimental errors determines the reliability and usefulness of any experimental investigation. Thus, it is important to understand how various test techniques are affected by expected experimental errors. Here, a semi-analytical method based on the concept of condition number is explored for systematic investigation of the sensitivity of spherical indentation to experimental errors. The method is employed to investigate the reliability of various possible spherical indentation protocols, providing a ranking of the selected data reduction protocols from least to most sensitive to experimental errors. Explicit Monte Carlo sensitivity analysis is employed to provide further insight of selected protocol, supporting the ranking. The results suggest that the proposed method for estimating the sensitivity to experimental errors is a useful tool. Moreover, in the case of spherical indentation, the experimental errors must be very small to give reliable material properties.

Experimental Verification of Model Pressurized Thick-Walled Cylinder With Numerical and Theoretical Methods

2011 ◽  
Author(s):  
Sunilbhai P. Macwan ◽  
Zhong Hu ◽  
Fereidoon Delfanian
Keyword(s):  
Hoop Stress ◽  
High Stress ◽  
Numerical Data ◽  
Cylinder Wall ◽  
Hoop Strain ◽  
Cylindrical Structures ◽  
Component Testing ◽  
Element Simulation ◽  
Pressurized Cylinder ◽  
Walled Cylinder

Pressurized thick-walled cylinders undergo repeated cycles of high stress and temperatures that may severely shorten the life of the component. Testing pressurized cylinder can help to evaluate the strength of the cylinder. This research seeks to determine the pressure to which the component is subjected by instrumenting the outside of the cylinder, and to evaluate hoop strain and hoop stress of the internal and external surface of the pressurized thick-walled cylinder. This study provides experimental results and then compares them with theoretical and numerical data for the cylinder under investigation. Using the experimental method, an axial load up to 15,000 lb is applied to the cylinder using a Landmark 370 MTS unit to generate pressure inside the cylinder wall. Lame´ equations are used to calculate hoop stress theoretically. The numerical data is obtained using finite element simulation (ANSYS) to calculate hoop stress and hoop strain at the internal and external surfaces of the cylinder. This work provides useful information for evaluating the strength of thick-walled cylindrical structures in a laboratory setting.

A Study of the Residual Stress Distribution in an Autofrettaged, Thick-Walled Cylinder With Cross-Bore

2004 ◽  
Vol 126 (4) ◽  
pp. 497-503 ◽  
Author(s):  
Amer Hameed ◽  
R. D. Brown ◽  
John Hetherington
Keyword(s):  
Residual Stress ◽  
Circumferential Stress ◽  
Stress Profile ◽  
Outer Diameter ◽  
Residual Stress Field ◽  
Element Analysis ◽  
Residual Stress Profile ◽  
Gun Barrel ◽  
The Cross ◽  
Walled Cylinder

It may be necessary to provide a radial opening such as gas evacuator holes, or an opening to operate the unlocking of the bolt mechanism by means of exhaust gases, in a gun barrel, which is a thick walled cylinder. A three dimensional finite element analysis has been performed to evaluate the effect of introducing a radial cross-bore in an autofrettaged thick-walled cylinder. From the analysis of the cross-bored autofrettaged cylinder, it was observed that there is a severe localized change in the residual stress profile in the vicinity of the cross-bore. The residual circumferential stress increases in compression at the bore. Similarly it increases in tension at the outer diameter, thus making the outer diameter more vulnerable to fatigue failure or crack initiation under stresses arising as a result of firing. Analyses were also performed by varying the cross-bore diameter and it was observed that, by increasing the diameter of the radial hole, the residual circumferential stress at the bore reduces, while it increases at the outer diameter, with an increase in the cross bore diameter. The re-pressurization pressure of an autofrettaged cylinder with radial cross-bore was found to be approximately 65 percent less than the actual autofrettage pressure in a particular case discussed in this paper. A comparison is also made with the residual stress field which would result if the cross-bore was machined before autofrettage.

scholarly journals The influence of the internal ballistic pressure on the rifled barrel stress response

2020 ◽  
Vol 70 (2) ◽  
pp. 41-46
Author(s):  
Abaci Boukera ◽  
Aleksandar Kari ◽  
Damir Jerković ◽  
Nebojša Hristov
Keyword(s):  
Mathematical Model ◽  
Stress Response ◽  
Cross Section ◽  
3D Models ◽  
The Other ◽  
Firing Process ◽  
Propellant Combustion ◽  
Gun Barrel ◽  
Walled Cylinder ◽  
Good Agreement

This paper focused on the 12.7 mm gun barrel stress response caused by the pressure of the gunpowder gases. During the firing process, the barrel is loaded by different mechanical, chemical and thermal loads. In this paper except the pressure of the propellant combustion, all the other loads were ignored. The pressure loads are obtained with a mathematical model of the interior ballistic. The Lame equations for the thick-walled cylinder were used to calculate the barrel stress response. The loads are applied on a certain barrel cross-section for a defined time. Two 3D models of the barrel with and without grooves were used to perform a numerical simulation. A comparison between results for the two types of barrels shows a good agreement between the stresses obtained by the analytical and numerical methods.

Design of Pressurized Cylinders for High-Temperature Applications

1960 ◽  
Vol 82 (2) ◽  
pp. 477-481
Author(s):  
J. F. Traexler
Keyword(s):  
Steady State ◽  
High Temperature ◽  
Creep Rate ◽  
Plane Strain ◽  
Material Properties ◽  
Rate Function ◽  
Specific Form ◽  
Steady State Creep ◽  
Numerical Examples ◽  
Walled Cylinder

General equations for the stresses in a thick-walled cylinder in a state of plane strain are derived considering “steady-state” creep. A specific form of the creep-rate function is assumed and numerical examples are included to show the effect of geometry and material properties.

Study on Acoustics in Buildings

2021 ◽  
Vol 9 (9) ◽  
pp. 461-494
Author(s):  
Karthik Boppana
Keyword(s):  
Civil Engineer ◽  
Best Practices ◽  
Material Properties ◽  
Sound Quality ◽  
Proper Understanding ◽  
Factors Influencing ◽  
Lack Of Information ◽  
Insufficient Amount ◽  
The Subject

Abstract: Acoustics in buildings is that part of science in which importance has been given to the sound quality in building, which enables a proper understanding of the different factors influencing the same. Acoustics being one of the important factor which enables in reduction of transmission of noise and enable a better sound quality in the room. But however either very less or insufficient amount of work has been put in considering the scope of the subject. Some other limitations are builders either do not give priority to that aspect due to lack of information or the improper design and poor implementation. Also The Indian Standard Codes in this area are too old and need updation considering the Modern Scenario and Modern Construction Practices. So efforts have been made to consider this situation and find the best practices, recent innovations and methodologies which could help in maintaining proper Acoustics in Buildings, Halls, Auditorium's etc. And what role could a Civil Engineer play in elimination of this problem. Keywords: Acoustics, Buildings, Material Properties

MEMS Metrology Using Resonant Structures

2001 ◽  
Author(s):  
A. Miller Allen ◽  
George C. Johnson
Keyword(s):  
Analytical Model ◽  
Material Properties ◽  
Analytical Method ◽  
A Priori ◽  
Experimental Results ◽  
A Priori Knowledge ◽  
Comb Drive ◽  
Resonant Frequencies ◽  
Resonant Structures

Abstract We present an analytical method and experiment to determine the “as-built” geometry of surface micro-machined micro-electromechanical structures. The analysis is based on the use of the lateral resonant frequencies of electrostatic comb drive resonators. The method can be used in situ and does not require a priori knowledge of the mechanical material properties of the structure. The variation between designed geometry and “as-built” geometry is determined from a fit of experimental results to the analytical model.

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