A Comparison of Methods for Predicting Residual Stresses in Strain-Hardening, Autofrettaged Thick Cylinders, Including the Bauschinger Effect

2005 ◽  
Vol 128 (2) ◽  
pp. 217-222 ◽  
Author(s):  
Michael C. Gibson ◽  
Amer Hameed ◽  
Anthony P. Parker ◽  
John G. Hetherington
Keyword(s):  
Finite Element ◽  
High Pressure ◽  
Strain Hardening ◽  
Plane Strain ◽  
Bauschinger Effect ◽  
Pressure Vessels ◽  
Operating Pressure ◽  
Working Pressure ◽  
Element Analysis ◽  
Compressive Stresses

High-pressure vessels, such as gun barrels, are autofrettaged in order to increase their operating pressure and fatigue life. Autofrettage causes plastic expansion of the inner section of the cylinder, setting up residual compressive stresses at the bore after relaxation. Subsequent application of pressure has to overcome these compressive stresses before tensile stresses can be developed, thereby increasing its fatigue lifetime and safe working pressure. This paper presents the results from a series of finite element models that have been developed to predict the magnitude of these stresses for a range of end conditions: plane stress and several plane-strain states (open and closed ended, plus true plane strain). The material model is currently bilinear and allows consideration of strain hardening and the Bauschinger effect. Results are compared to an alternative numerical model and a recent analytical model (developed by Huang), and show close agreement. This demonstrates that general purpose finite element analysis software may be used to simulate high-pressure vessels, justifying further refining of the models.

Finite Element Analysis of Residual Stresses in Threaded End Closures

1991 ◽  
Vol 113 (3) ◽  
pp. 398-401 ◽  
Author(s):  
A. Chaaban ◽  
U. Muzzo
Keyword(s):  
Finite Element ◽  
Residual Stresses ◽  
Bauschinger Effect ◽  
High Stress ◽  
Empirical Method ◽  
Pressure Vessels ◽  
Element Analysis ◽  
High Stress Concentration ◽  
Proof Testing ◽  
Pressure Cycle

Due to the high stress concentration at the root of the first active thread in threaded end closures of high pressure vessels, yielding may occur in this region during the application of the first pressure cycle or proof testing. This overstraining introduces residual stresses that influence the fatigue performance of the vessel. This paper presents a parametric analysis of threaded end closures using elastic and elasto-plastic finite element solutions. The results are used to discuss the influence of these residuals on the estimated fatigue life when the vessel is subjected to repeated internal pressure. A simple empirical method to allow for the Bauschinger effect of the material is also proposed.

Residual Stress Induced by Waterjet Peening: A Finite Element Analysis

2004 ◽  
Vol 126 (3) ◽  
pp. 333-340 ◽  
Author(s):  
S. Kunaporn ◽  
M. Ramulu ◽  
M. G. Jenkins ◽  
M. Hashish
Keyword(s):  
Residual Stress ◽  
Finite Element Analysis ◽  
Finite Element ◽  
High Pressure ◽  
Stress Fields ◽  
Process Conditions ◽  
Workpiece Material ◽  
Element Analysis ◽  
Compressive Stresses ◽  
Interfacial Pressure

The concept of multiple droplet impacts resulting from ultra high-pressure waterjet (UHPWJ) was used to develop a mathematical model to describe the effect of interfacial pressure on the underlying workpiece material. A non-linear elastic-plastic finite element analysis (FEA) was carried out in this study using the interfacial pressure model to predict residual compressive stresses. This three-dimensional FEA model was based on quasi-static considerations to provide prediction of both magnitude and depth of residual stress fields in a 7075-T6 aluminum alloy (A17075-T6). Results of the FEA modeling were in good agreement with experimental measurements. Effects of applied pressures on the residual stress fields are also presented and discussed as a method of estimating high-pressure waterjet induced compressive stresses under varying process conditions for peening.

Material Models for the Finite Element Analysis of Materials Exhibiting a Pronounced Bauschinger Effect

2006 ◽  
Vol 128 (2) ◽  
pp. 190-195 ◽  
Author(s):  
Rolf R. de Swardt
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Strain Hardening ◽  
Bauschinger Effect ◽  
Element Analysis ◽  
Material Models ◽  
Reverse Loading ◽  
The Finite Element Analysis ◽  
Dimensional Finite Element ◽  
Reverse Yielding

Realistic material models have been developed on the basis of the experimental investigation of reverse loading with actual Bauschinger effect and implemented into a two-dimensional finite element computer program. The developed program is capable of treating the elastoplastic deformation behavior of thick-walled cylinders during both loading and unloading phases. Strain hardening may occur during loading, and reverse yielding may occur during unloading at a yield strength significantly reduced due to the Bauschinger effect. Three different models for the reverse hardening are presented. Strain hardening during reverse yielding may have a different slope than for forward loading, and it may also be nonlinear. The intended application is for autofrettage analysis of thick-walled cylinders. Being a numerical solution, it will also be very useful for finite element analysis of residual stress experimental procedures and also in the determination of more accurate stress intensity factors for autofrettaged cylinders that had undergone reverse yielding due to the Bauschinger effect.

Finite Element Analysis of Deformation and Flow of Two-Way Cartridge Valve under Different Pressures

2012 ◽  
Vol 502 ◽  
pp. 431-435
Author(s):  
Han Wu Liu ◽  
Jun Ming Liu ◽  
Fan Feng
Keyword(s):  
Finite Element ◽  
Flow Rate ◽  
Strength Analysis ◽  
Operating Pressure ◽  
Working Pressure ◽  
Element Analysis ◽  
Valve Body ◽  
Rate Region ◽  
Weak Part ◽  
Cartridge Valves

In the working process of the two way cartridge valve, deformation and stress are generated by the effect of the changed internal fluid pressures. In this process, the flow of the liquid flowing through the cross section also changes with it. To analyse the stress and deformation distributions of the cartridge valve under the different pressures and the flow analysis in different flow rates and different pressures, finite element method has been used in this paper for analysis and calculation in order to find the structure weak part, the instable flow rate region and the part which hinder the flow rate increased. The results show that: the phenomenon of stress concentration significantly existed in the opening part on the outlet side of the two-way cartridge valve. Under the maximum operating pressure (the maximum working pressure is 31.5 MPa, the maximum flow rate is 4500 L / min), the deformation was larger in the part of girdle. There was nearly no deformation on the upside of the valve body and the stress was less. So, the valve body was the redundant part of two-way cartridge valves. The instable flow rate region was located in the region of the two-way cartridge valve opening across. In the junction of the export of plug-in mounting component and the plug-in mounting block, the flow of liquid was impeded because of its much block and angular structure. The analysis results above have laid a theoretical foundation for the fatigue strength analysis and structural optimization of two-way cartridge valves.

Residual Stress Induced by Waterjet Peening: A Finite Element Analysis

2003 ◽  
Author(s):  
Sawalee Kunaporn ◽  
Mamidala Ramulu ◽  
Michael G. Jenkins ◽  
Mohammed Hashish
Keyword(s):  
Residual Stress ◽  
Finite Element Analysis ◽  
Finite Element ◽  
High Pressure ◽  
Stress Fields ◽  
Process Conditions ◽  
Workpiece Material ◽  
Element Analysis ◽  
Compressive Stresses ◽  
Interfacial Pressure

The concept of multiple droplet impacts resulting from ultra high-pressure waterjet (UHPWJ) was used to develop a mathematical model to describe the effect of interfacial pressure on the underlying workpiece material. A non-linear elastic-plastic finite element analysis (FEA) was carried out in this study using the interfacial pressure model to predict residual compressive stresses. This three-dimensional FEA model was based on quasi-static considerations to provide prediction of both magnitude and depth of residual stress fields in a 7075-T6 aluminum alloy (A17075-T6). Results of the FEA modeling were in good agreement with experimental measurements. Effects of applied pressures on the residual stress fields are also presented and discussed as a method of estimating high-pressure waterjet induced compressive stresses under varying process conditions for peening.

Development of Design Rules for Nozzles in Pressure Vessels for the ASME B&PV Code, Section VIII, Division 2

2011 ◽  
Author(s):  
Zhenning Cao ◽  
Les Bildy ◽  
David A. Osage ◽  
J. C. Sowinski
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Pressure Vessels ◽  
Experimental Results ◽  
Working Pressure ◽  
Element Analysis ◽  
Design Rules ◽  
Pressure Area ◽  
Section Viii ◽  
Division 2

The theory behind the pressure-area method that is incorporated in the ASME B&PV Code, Section VIII-2 is presented in this paper. Background and insight to the nozzle rules of ASME B&PV Code, Section VIII, Division 2, Part 4, paragraph 4.5 are also provided. Recommendations for modifying the current nozzles rules, those published in ASME B&PV Code, Section VIII, Division 2, 2010 Edition, is given based on continuing research and development efforts. A comparison between experimental results, results derived from detailed finite element analysis (FEA), the rules prior to the VIII-2 Rewrite (2004 Edition), and the rules in VIII-2 are provided in terms of a design margin and permissible maximum allowable working pressure (MAWP) computed with the design rules. A complete description of the theory including a commentary and comparison to experimental results is provided in WRC529 [1].

A Study on Fatigue Life Evaluation of Pressure Vessel Made of ASME SA240-316L Material Using Numerical Analysis

2019 ◽  
Vol 893 ◽  
pp. 1-5 ◽  
Author(s):  
Eui Soo Kim
Keyword(s):  
Finite Element ◽  
Fatigue Life ◽  
Pressure Vessel ◽  
Life Prediction ◽  
Pressure Vessels ◽  
Physical Damage ◽  
Element Analysis ◽  
Internal Damage ◽  
Life Evaluation ◽  
Fatigue Life Evaluation

Pressure vessels are subjected to repeated loads during use and charging, which can causefine physical damage even in the elastic region. If the load is repeated under stress conditions belowthe yield strength, internal damage accumulates. Fatigue life evaluation of the structure of thepressure vessel using finite element analysis (FEA) is used to evaluate the life cycle of the structuraldesign based on finite element method (FEM) technology. This technique is more advanced thanfatigue life prediction that uses relational equations. This study describes fatigue analysis to predictthe fatigue life of a pressure vessel using stress data obtained from FEA. The life prediction results areuseful for improving the component design at a very early development stage. The fatigue life of thepressure vessel is calculated for each node on the model, and cumulative damage theory is used tocalculate the fatigue life. Then, the fatigue life is calculated from this information using the FEanalysis software ADINA and the fatigue life calculation program WINLIFE.

scholarly journals Fractographical Analysis and Biomechanical Considerations of a Tooth Restored With Intracanal Fiber Post: Report of the Fracture and Importance of the Fiber Arrangements

2016 ◽  
Vol 41 (5) ◽  
pp. E149-E158 ◽  
Author(s):  
VF Wandscher ◽  
CD Bergoli ◽  
IF Limberger ◽  
TP Cenci ◽  
P Baldissara ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Glass Fiber ◽  
Shear Stresses ◽  
Fiber Post ◽  
Element Analysis ◽  
Parallel Fibers ◽  
Tooth Structure ◽  
Anterior Teeth ◽  
Compressive Stresses

SUMMARY Objective: This article aims to present a fractographic analysis of an anterior tooth restored with a glass fiber post with parallel fiber arrangement, taking into account force vectors, finite element analysis, and scanning electron microscopy (SEM). Methods: A patient presented at the Faculty of Dentistry (Federal University of Santa Maria, Brazil) with an endodontically treated tooth (ETT), a lateral incisor that had a restorable fracture. The treatment was performed, and the fractured piece was analyzed using stereomicroscopy, SEM, and finite element analysis. Results: The absence of remaining coronal tooth structure might have been the main factor for the clinical failure. We observed different stresses actuating in an ETT restored with a fiber post as well as their relationship with the ultimate fracture. Tensile, compression, and shear stresses presented at different levels inside the restored tooth. Tensile and compressive stresses acted together and were at a maximum in the outer portions and a minimum in the inner portions. In contrast, shear stresses acted concomitantly with tensile and compressive stresses. Shear was higher in the inner portions (center of the post), and lower in the outer portions. This was confirmed by finite element analysis. The SEM analysis showed tensile and compression areas in the fiber post (exposed fibers=tensile areas=lingual surface; nonexposed fibers=compression areas=buccal surface) and shear areas inside the post (scallops and hackle lines). Stereomicroscopic analysis showed brown stains in the crown/root interface, indicating the presence of microleakage (tensile area=lingual surface). Conclusion: We concluded that glass fiber posts with parallel fibers (0°), when restoring anterior teeth, present a greater fracture potential by shear stress because parallel fibers are not mechanically resistant to support oblique occlusal loads. Factors such as the presence of remaining coronal tooth structure and occlusal stability assist in the biomechanical equilibrium of stresses that act upon anterior teeth.

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