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.

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.

Investigation of Residual Stress Development During Swage Autofrettage, Using Finite Element Analysis

2009 ◽  
Author(s):  
Michael C. Gibson ◽  
Amer Hameed ◽  
John G. Hetherington
Keyword(s):  
Finite Element ◽  
Residual Stresses ◽  
Axial Stress ◽  
Slope Angle ◽  
Subsequent Development ◽  
Element Model ◽  
Pressure Vessels ◽  
Element Analysis ◽  
Reverse Yielding

Swaging is one method of autofrettage, a means of pre-stressing high-pressure vessels to increase their fatigue lives and load bearing capacity. Swaging achieves the required deformation through physical interference between an oversized mandrel and the bore diameter of the tube, as it is pushed through the tube. A Finite Element model of the swaging process was developed, in ANSYS, and systematically refined, to investigate the mechanism of deformation and subsequent development of residual stresses. A parametric study was undertaken, of various properties such as mandrel slope angle, parallel section length and friction coefficient. It is observed that the axial stress plays a crucial role in the determination of the residual hoop stress and reverse yielding. The model, and results obtained from it, provides a means of understanding the swaging process and how it responds to different parameters. This understanding, coupled with future improvements to the model, potentially allows the swaging process to be refined, in terms of residual stresses development and mandrel driving force.

Acoustic Vibration Induced Fatigue in Pipe Joints

2015 ◽  
Author(s):  
Ajay Prakash ◽  
Philip Diwakar ◽  
Dan Lin ◽  
Paul Deane ◽  
Yuqing Liu ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Sound Pressure ◽  
High Stress ◽  
Acoustic Vibration ◽  
Acoustic Energy ◽  
Piping System ◽  
Element Analysis ◽  
High Stress Concentration ◽  
Pipe Joints

High acoustic energy has the potential to cause severe acoustic induced vibration (AIV) that can lead to fatigue failure at high stress concentration locations (discontinuities) in a piping system. AIV at pipe junctions (Lateral, Tee, and Wye) and welded support attachments (trunnions and shoes) is evaluated using Finite Element Analysis. At different size pipe junctions, branch and header pipe shells may be subjected to different sound pressure. Also, inertia associated with different wall thickness(s) can lead to very different dynamic response of the two shell walls. The effect of these differences on AIV response is analyzed. Resulting response for different junction reinforcement designs is evaluated and compared to an unreinforced ‘stub-on’ configuration to assess the designs.

Failure Analysis of Full Delamination on the Stacked Die Leaded Packages

2003 ◽  
Vol 125 (3) ◽  
pp. 392-399 ◽  
Author(s):  
T. Y. Lin ◽  
Z. P. Xiong ◽  
Y. F. Yao ◽  
Lane Tok ◽  
Z. Y. Yu ◽  
...  
Keyword(s):  
Finite Element ◽  
Adhesion Strength ◽  
High Stress ◽  
Consumer Products ◽  
Lead Frame ◽  
Element Analysis ◽  
Factors Affecting ◽  
Temperature Cycles ◽  
High Stress Concentration ◽  
Die Attach

There has been significant demand for stacked die technology during the past few years. The stacked die devices are mainly used in portable consumer products. This kind of silicon integration technology provides flexibility in space reduction, weight savings, and excellent electrical functionality. In this article, the stacked die construction was built into the leaded package. It was found that the test vehicles had full delamination at the lead-frame paddle/mold compound interface after 100 temperature cycles (−65°C to 150°C) with moisture preconditioning at level 3 (60°C at 60% relative humidity for 40 h) although the electrical test passed 1000 temperature cycles. The fishbone diagram was used to identify the possible failure root causes. The material, process, and design factors were extensively evaluated by the experiments and finite element analysis. The evaluation results showed that die attach paste voids were major factors affecting the package integrity and could produce the delamination initiation at the edge of the die attach paste and propagate down to the lead-frame paddle/mold compound interface due to high stress concentration and weak adhesion strength. The finite element analyses were implemented to address the stress distribution in the stacked die package and verified by the scanning acoustic microscope. It demonstrated that excellent package integrity could be obtained by applying the void-free die attach paste and improving the adhesion strength at the lead-frame paddle level.

Numerical Analysis of Contact Stresses Between Mooring Chain Links and Potential Consequences for Fatigue Damage

2013 ◽  
Author(s):  
Philippe Bastid ◽  
Simon D. Smith
Keyword(s):  
Finite Element ◽  
Residual Stresses ◽  
Contact Zone ◽  
Fatigue Damage ◽  
Contact Region ◽  
High Stress ◽  
Breaking Load ◽  
High Stress Concentration ◽  
Cyclic Stresses ◽  
Chain Links

Design codes for offshore mooring systems recommend proof loading chain links to around 70% of the specified breaking load of the chain (API RP 2FP1, Lloyd’s Register). This is primarily to check that the chain will safely resist the service loads and will not excessively elongate. It is assumed that the proof load also generates compressive residual stresses at the interlink contact region and also at the point of the intrados (KT point) where a high stress concentration occurs during tensile loading. Tests have shown that proof loading improves the fatigue performance of chain under cyclic axial loads. Elastic-plastic finite element analyses of the proof loading have been performed. These analyses have shown that the proof loading also generates very high tensile residual stresses in the region surrounding the interlink contact zone. This region also experiences significant in-service cyclic stresses under cyclic tension or out-of-plane bending. The combination of the cyclic stresses and high tensile residual stress is of concern and it is proposed that the periphery of the interlink contact zone should be carefully reviewed. It is understood that chain link fatigue at present is only based on the risk of fatigue damage at the KT point. This paper presents and discusses results of finite element stress analyses of studless chains of different sizes and grades, and show the relative fatigue sensitivity of the KT and contact regions. The chain grade, dimensions and loading regime are shown to be important.

Investigation of Residual Stress Development During Swage Autofrettage, Using Finite Element Analysis

2014 ◽  
Vol 136 (2) ◽  
Author(s):  
Michael C. Gibson ◽  
Amer Hameed ◽  
John G. Hetherington
Keyword(s):  
Finite Element ◽  
Residual Stresses ◽  
Axial Stress ◽  
Slope Angle ◽  
Subsequent Development ◽  
Element Model ◽  
Pressure Vessels ◽  
Element Analysis ◽  
Reverse Yielding

Swaging is one method of autofrettage, a means of prestressing high-pressure vessels to increase their fatigue lives and load bearing capacity. Swaging achieves the required deformation through physical interference between an oversized mandrel and the bore diameter of the tube, as it is pushed through the tube. A finite element model of the swaging process was developed, in ansys, and systematically refined, to investigate the mechanism of deformation and subsequent development of residual stresses. A parametric study was undertaken, of various properties such as mandrel slope angle, parallel section length, and friction coefficient. It is observed that the axial stress plays a crucial role in the determination of the residual hoop stress and reverse yielding. The model, and results obtained from it, provides a means of understanding the swaging process and how it responds to different parameters. This understanding, coupled with future improvements to the model, potentially allows the swaging process to be refined, in terms of residual stresses development and mandrel driving force.

Analysis and validation of femur bone data using finite element method under static load condition

2019 ◽  
Vol 233 (16) ◽  
pp. 5547-5555 ◽  
Author(s):  
S Mathukumar ◽  
VA Nagarajan ◽  
A Radhakrishnan
Keyword(s):  
Finite Element ◽  
Stress Concentration ◽  
Static Load ◽  
High Stress ◽  
Load Condition ◽  
Computational Method ◽  
Medical Attention ◽  
Element Analysis ◽  
High Stress Concentration ◽  
Femur Bone

Humans face bone fracture when they unfortunately met an accident, which requires timely medical attention for healing and repairing the fractured bone; otherwise that paralyzes their life. 3D modeling technique with computational method is very helpful at the side of doctors for healing and repairing the damaged bones. Fractional bone healing is one of the natural processes, which regain the mechanical reliability of the bone to a limited level of failures. The relationship between the biology and mechanics has introduced a new branch namely biomechanics. Various biomechanics models were used to identify the fracture for different patients and helps in the fracture treatment. The aim of this work is to find out the high stress concentration area of the femur bone, which has been extracted as image from computer tomography scanner. The retrieved noise-free femur bone image is tested by the static load condition with the help of the finite element analysis. The result obtained from the testing of different loads has been compared with the existing literature. It is found that the femur bone has tensile and compressive stress, and the neck area of the femur is at a very high stress concentration. The outcome of this work is much supportive to orthopedic surgeons in femur surgery and bone prosthesis by avoiding experiments on femur bone.

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.

Residual Stress Estimation in Crossbores With Bauschinger Effect Inclusion Using FEM and Strain Energy Density

1999 ◽  
Vol 121 (4) ◽  
pp. 358-363 ◽  
Author(s):  
E. A. Badr ◽  
J. R. Sorem ◽  
S. M. Tipton
Keyword(s):  
Finite Element Analysis ◽  
Stress Concentration ◽  
Strain Energy Density ◽  
Strain Energy ◽  
Analytical Approach ◽  
Bauschinger Effect ◽  
High Stress ◽  
Element Analysis ◽  
Elastic Plastic ◽  
High Stress Concentration

Crossbore intersections in liquid ends of positive displacement pumps (PDPs) have regions with high stress concentration. Due to the cyclic loading that occurs in most PDPs, these stress concentration points are susceptible to fatigue cracking. In order to prolong their life, the liquid ends are often overpressurized (autofrettaged), thus inducing beneficial compressive hoop stresses in these critical regions upon removal of the autofrettage pressure. This autofrettage process drives the region of high stress concentration beyond the elastic limit and well into the elastic-plastic region. Elastic-plastic stresses and strains due to loading and unloading were analyzed in crossbore geometries, with Bauschinger effect included, using 3-D finite element analysis of the liquid end. For comparison, an analytical approach was developed, based on the strain energy density criterion first proposed by Glinka. The approach was modified to include the Bauschinger effect for precise estimation of such stresses and strains. Good correlation was observed between elastic-plastic crossbore stresses and strains predicted by the analytical approach and the finite element analysis.

Localized Autofrettage as a Design Tool for the Fatigue Improvement of Cross-Bored Cylinders

1998 ◽  
Vol 120 (4) ◽  
pp. 393-397 ◽  
Author(s):  
A. E. Segall ◽  
C. Tricou ◽  
M. Evanko ◽  
J. C. Conway
Keyword(s):  
Fatigue Life ◽  
Residual Stresses ◽  
High Stress ◽  
Circular Crack ◽  
Design Tool ◽  
Element Analysis ◽  
High Stress Concentration ◽  
Significant Extension ◽  
The Cross ◽  
Machining Operations

An investigation was launched into the feasibility of improving the fatigue life of thick-walled cylinders with cross-bores by using a localized autofrettage technique. This technique utilized the high stress concentration at the cross-bore to induce localized residual stresses using relatively low internal pressures. An elastic-plastic finite-element analysis indicated that the resulting residual stresses in the vicinity of the cross-bore were predominately compressive and not sufficient in magnitude to induce reverse plasticity. When the resulting residual stresses were used with an elastic fracture-mechanics assessment of a quarter-circular crack at the intersection of the cylinder and cross-bore inner diameter, a significant extension of fatigue life was shown to be possible. In addition to prolonging the useful life of the cylinder, the localized residual stresses were shown to be possible at pressures below the yield threshold for the thick-walled cylinder. Thus, reverse plasticity, permanent deformations, and the need for post-autofrettage machining operations that could inadvertently lessen the beneficial results of a traditional autofrettage were avoided.

Sign in / Sign up

Export Citation Format

Share Document