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.

Simulation of Partial Autofrettage by Thermal Loads

1980 ◽  
Vol 102 (3) ◽  
pp. 314-318 ◽  
Author(s):  
M. A. Hussain ◽  
S. L. Pu ◽  
J. D. Vasilakis ◽  
P. O’Hara
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Finite Elements ◽  
Residual Stresses ◽  
Finite Differences ◽  
Thermal Loading ◽  
Thermal Stresses ◽  
Intensity Factors ◽  
Stress Patterns ◽  
Walled Cylinder

The effect of favorable residual stresses of an autofrettaged tube is well known [1]. In many instances there is redistribution of these stresses due to changes of geometrical configurations such as the presence of keyways, riflings, cracks, etc. The problem, in general, can be studied by discretization carrried out either by finite elements or by finite differences; however, it is usually not possible to incorporate the redistributed residual stress patterns due to the presence of such geometrical changes. This difficulty is overcome by simulation of residual stresses by certain active loadings. The simulation by dislocation and equivalent thermal loading for a fully autofrettaged tube is well known. In this paper we extend the thermal loading to simulate a partially autofrettaged case. Thermal stresses due to the simulated thermal loading computed from finite elements (NASTRAN) and finite differences are in excellent agreement with residual stresses for various degrees of overstrain. The simplicity of the method to incorporate the redistribution of residual stress due to the presence of geometrical discontinuities is illustrated by a finite element (APES) computation of stress intensity factors at an OD crack tip in a partially autofrettaged, thick-walled cylinder.

Random impact FEM simulation of irregularly-shaped media for parametric study of vibratory surface enhancement

2021 ◽  
pp. 095440542199012
Author(s):  
Jing Zhang ◽  
Joselito Yam Alcaraz ◽  
Swee-Hock Yeo ◽  
Arun Prasanth Nagalingam ◽  
Abhay Gopinath
Keyword(s):  
Residual Stress ◽  
Fatigue Life ◽  
Parametric Study ◽  
Thermal Loading ◽  
Low Cycle Fatigue ◽  
Fem Simulation ◽  
Surface Finishing ◽  
Aerospace Materials ◽  
Surface Enhancement ◽  
Steel Balls

Aerospace materials experience high levels of mechanical and thermal loading, high/low cycle fatigue, and damage from foreign objects during service, which can lead to premature retirement. Mechanical surface treatments of metallic components, for example, fan blades and blisks, are proven to improve fatigue life, improve wear resistance and avoid stress corrosion by introducing work hardening, compressive residual stresses of sub-surface, and surface finishing. Vibropeening can enhance aerospace materials’ fatigue life involving the kinetic agitation of hardened steel media in a vibratory finishing machine that induces compressive stresses into the component sub-layers while keeping a finished surface. Spherical steel balls are the most widely used shape among steel-based media and have been explored for decades. However, they are not always versatile, which cannot access deep grooves, sharp corners, and intricate profiles. Steel ballcones or satellites, when mixed with round steel balls and other steel media (diagonals, pins, eclipses, cones), works very well in such areas that ball-shaped media are unable to reach. However, a methodology of study the effect of irregularly-shaped media in surface enhancement processes has not been established. This paper proposes a finite element-based model to present a methodology for the parametric study of vibratory surface enhancement with irregularly-shaped media and investigates residual stress profiles within a treated area of an Inconel component. The methodology is discussed in detail, which involves a stochastic simulation of orientation, impact force, and impact location. The contrasting effects of a high aspect ratio, or an edge contact, as opposed to rounded and oblique contacts are demonstrated, with further analysis on the superposition of these effects. Finally, the simulation results are compared with actual residual stress measurements and was found to have a max percent difference of 34% up to 20 [Formula: see text]m below the media surface.

Stress and Fatigue Life Modeling of Cannon Breech Closures Including Effects of Material Strength and Residual Stress

2000 ◽  
Vol 123 (1) ◽  
pp. 150-154
Author(s):  
John H. Underwood ◽  
Michael J. Glennon
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Fatigue Life ◽  
Yield Strength ◽  
Residual Stresses ◽  
Solid Mechanics ◽  
Element Model ◽  
Pressure Vessels ◽  
Material Strength ◽  
Element Analysis

Laboratory fatigue life results are summarized from several test series of high-strength steel cannon breech closure assemblies pressurized by rapid application of hydraulic oil. The tests were performed to determine safe fatigue lives of high-pressure components at the breech end of the cannon and breech assembly. Careful reanalysis of the fatigue life tests provides data for stress and fatigue life models for breech components, over the following ranges of key parameters: 380–745 MPa cyclic internal pressure; 100–160 mm bore diameter cannon pressure vessels; 1040–1170 MPa yield strength A723 steel; no residual stress, shot peen residual stress, overload residual stress. Modeling of applied and residual stresses at the location of the fatigue failure site is performed by elastic-plastic finite element analysis using ABAQUS and by solid mechanics analysis. Shot peen and overload residual stresses are modeled by superposing typical or calculated residual stress distributions on the applied stresses. Overload residual stresses are obtained directly from the finite element model of the breech, with the breech overload applied to the model in the same way as with actual components. Modeling of the fatigue life of the components is based on the fatigue intensity factor concept of Underwood and Parker, a fracture mechanics description of life that accounts for residual stresses, material yield strength and initial defect size. The fatigue life model describes six test conditions in a stress versus life plot with an R2 correlation of 0.94, and shows significantly lower correlation when known variations in yield strength, stress concentration factor, or residual stress are not included in the model input, thus demonstrating the model sensitivity to these variables.

Finite Element Analysis of the Rolling Contact Fatigue Life of Railcar Wheels

2008 ◽  
Vol 575-578 ◽  
pp. 1461-1466
Author(s):  
Byeong Choon Goo ◽  
Jung Won Seo
Keyword(s):  
Heat Treatment ◽  
Residual Stress ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Fatigue Life ◽  
Contact Fatigue ◽  
Rolling Contact ◽  
Element Analysis ◽  
Railway Vehicles ◽  
Contact Fatigue Life

Railcar wheels and axles belong to the most critical components in railway vehicles. The service conditions of railway vehicles have been more severe in recent years due to speed-up. Therefore, a more precise evaluation of railcar wheel life and safety has been requested. Wheel/rail contact fatigue and thermal cracks due to braking are two major mechanisms of the railcar wheel failure. One of the main sources influencing on the contact zone failure is residual stress. The residual stress in wheels formed during heat treatment in manufacturing changes in the process of braking. Thus the fatigue life of railcar wheels should be estimated by considering both thermal stress and rolling contact. Also, the effect of residual stress variation due to manufacturing process and braking process should be included in simulating contact fatigue behavior. In this paper, an evaluation procedure for the contact fatigue life of railcar wheels considering the effects of residual stresses due to heat treatment, braking and repeated contact load is proposed. And the cyclic stressstrain history for fatigue analysis is simulated by finite element analysis for the moving contact load.

Finite Element Analysis Model of Corrosion Fatigue for TIG Welding Workpiece

2016 ◽  
Vol 707 ◽  
pp. 154-158
Author(s):  
Somsak Limwongsakorn ◽  
Wasawat Nakkiew ◽  
Adirek Baisukhan
Keyword(s):  
Residual Stress ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Fatigue Life ◽  
Corrosion Fatigue ◽  
Welding Process ◽  
Simulation Software ◽  
Tig Welding ◽  
Element Analysis ◽  
Fea Model

The proposed finite element analysis (FEA) model was constructed using FEA simulation software, ANSYS program, for determining effects of corrosion fatigue (CF) from TIG welding process on AISI 304 stainless steel workpiece. The FEA model of TIG welding process was developed from Goldak's double ellipsoid moving heat source. In this paper, the residual stress results obtained from the FEA model were consistent with results from the X-ray diffraction (XRD) method. The residual stress was further used as an input in the next step of corrosion fatigue analysis. The predictive CF life result obtained from the FEA CF model were consistent with the value obtained from stress-life curve (S-N curve) from the reference literaturature. Therefore, the proposed FEA of CF model was then used for predicting the corrosion fatigue life on TIG welding workpiece, the results from the model showed the corrosion fatigue life of 1,794 cycles with testing condition of the frequency ( f ) = 0.1 Hz and the equivalent load of 67.5 kN (equal to 150 MPa) with R = 0.25.

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.

Stress Concentration and Stress Intensity for Pressurized Eroded Autofrettaged Thick Cylinders With Bauschinger Effect

2010 ◽  
Author(s):  
Q. Ma ◽  
C. Levy ◽  
M. Perl
Keyword(s):  
Stress Intensity ◽  
Stress Concentration ◽  
Bauschinger Effect ◽  
Thermal Loading ◽  
Yield Criterion ◽  
Pressure Vessels ◽  
Short Cracks ◽  
Finite Element Package ◽  
Von Mises ◽  
Walled Cylinder

Our previous studies have shown that stress intensity factors (SIFs) are influenced considerably from the presence of the Bauschinger Effect (BE) in thick-walled pressurized cracked cylinders. For some types of pressure vessels, such as gun barrels, working in corrosive environment, in addition to acute temperature gradients and repetitive high-pressure impulses, erosions can be practically induced. Those erosions cause stress concentration at the bore, where cracks can readily initiate and propagate. In this study, The BE on the SIFs will be investigated for a crack emanating from an erosion’s deepest point in a multiply eroded autofrettaged, pressurized thick-walled cylinder. A commercial finite element package, ANSYS, was employed to perform this type of analysis. A two-dimensional model, analogous to the authors’ previous studies, has been adopted for this new investigation. Autofrettage with and without BE, based on von Mises yield criterion, is simulated by thermal loading and the SIFs are determined by the nodal displacement method. The SIFs are evaluated for a variety of relative crack lengths, a0/t = 0.01–0.45 emanating from the tip of the erosion of different geometries including (a) semi-circular erosions of relative depths of 1–10 percent of the cylinder’s wall thickness, t; (b) arc erosions for several dimensionless radii of curvature, r′/t = 0.05–0.4; and (c) semi-elliptical erosions with ellipticities of d/h = 0.5–1.5, and erosion span angle, α, from 6 deg to 360 deg. The effective SIFs for relatively short cracks are found to be increased by the presence of the erosion and further increased due to the BE, which may result in a significant decrease in the vessel’s fatigue life. Deep cracks are found to be almost unaffected by the erosion, but are considerably affected by BE.

Residual Stress and Wave Reflectivity When Laser Peening Thin Curved Sections

2011 ◽  
Author(s):  
Arif Malik ◽  
Xiaopeng Lai ◽  
Kristina Langer
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Fatigue Life ◽  
Near Infrared ◽  
Experimental Testing ◽  
Turbine Blades ◽  
Value Added ◽  
Laser Peening ◽  
Widespread Application ◽  
Thin Sections

Laser Peening is an emerging technology that shows promise for extending the fatigue life of special-purpose metal components in the aerospace, automotive, medical, manufacturing, and other industries. While laser peening has been shown to extend the fatigue life of metal components such as turbine blades and other high value-added components, the technology is not yet understood well enough to deploy it cost-effectively, without extensive experimental testing, for widespread application in diverse industries. Because laser peening can adversely affect fatigue life if the process parameters are not selected appropriately, identification of tamping layers, pulse energy densities, shot patterns, and other parameters is critical to the component geometry, material, and loading. When laser peening thin sections, preliminary finite element studies indicate that reflectivity of shock waves can induces regions of residual stress or damage on opposing surfaces. Through a series of finite element simulations, this work explores the effects of stress wave reflectivity on component life for thin, curved, 6061-T6 aluminum alloy sections. The simulations are based on an 800 mJ, 5 ns pulsed, near-infrared laser, serves to define the pressure pulse boundary condition, and allow more reliable deployment of laser peening technology.

Laminated Ceramic Structures within Alumina / YTZP System Obtained by Low Pressure Joining

2007 ◽  
Vol 333 ◽  
pp. 219-222 ◽  
Author(s):  
Jonas Gurauskis ◽  
Antonio Javier Sanchez-Herencia ◽  
Carmen Baudín
Keyword(s):  
Finite Element Method ◽  
Residual Stress ◽  
Finite Element ◽  
Residual Stresses ◽  
Material Properties ◽  
Layered Materials ◽  
Processing Parameters ◽  
Spectroscopic Technique ◽  
Reinforcement Mechanism ◽  
Laminated Structures

The production of multilayer ceramics by laminating stacked green ceramic tapes is one of the most attractive methods to fabricate layered materials. In this work, a new lamination technique was employed to obtain laminated ceramic structures in the aluminazirconia system with residual stress compression at the outer layers. This reinforcement mechanism would lead to ceramics with changed material properties and R-curve behaviour. The optimization of processing parameters for fabrication of defect free monolithic and laminated structures is described. The residual stresses developed in the laminated structures are discussed in terms of the results obtained from piezo-spectroscopic technique measurements and finite element method calculations.

Influence of Material Model on Tensile Loaded Joint

2010 ◽  
Vol 165 ◽  
pp. 394-399 ◽  
Author(s):  
E. Szymczyk ◽  
Grzegorz Slawinski
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Numerical Analysis ◽  
Stress Field ◽  
Material Model ◽  
Finite Element Simulations ◽  
Residual Stress Field ◽  
Material Models ◽  
Riveted Joint ◽  
Load Conditions

The paper deals with the numerical analysis of a tensile loaded riveted joint. Finite element simulations of the upsetting process were carried out with the use of Marc code to determine the residual stress field. The contact with friction is defined between the mating parts of the joint. The computations were performed for four cases of material and load conditions and a comparison was performed on the basis of results obtained for standard elasto plastic and Gurson material models. Moreover, the influence of material model and residual stress on the tensile loaded joint was analyzed.

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