Analytical evaluation of thermally induced residual stresses in ground components

2003 ◽  
Vol 217 (5) ◽  
pp. 471-482 ◽  
Author(s):  
D G Walsh ◽  
A A Torrance ◽  
J Tiberg
Keyword(s):  
Experimental Data ◽  
Finite Element ◽  
Critical Temperature ◽  
Yield Strength ◽  
Residual Stresses ◽  
Material Properties ◽  
Analytical Evaluation ◽  
Simple Method ◽  
Thermally Induced

Although thermally induced tensile residual stresses have been known to occur in ground components, it has not been possible to predict the critical temperature at which these stresses begin to manifest themselves in the workpiece. In this paper, a model of the formation of thermally induced tensile residual stresses is proposed and a simple method of calculating the critical temperature above which tensile residual stresses occur is developed. The analysis makes use of dimensional methods to characterize the critical temperature. In addition, a formula characterizing the yield strength as a function of temperature was developed. The model was then validated using finite element techniques and some experimental data. The analysis reveals that it is possible to determine the critical temperature above which tensile residual stresses will be manifested based on readily available material properties. A case study illustrates the application of the technique.

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.

Stress–Strain Relationship of Polycaprolactone in Liquid Nitrogen for Finite Element Simulation of Cryogenic Micropunching Process

2020 ◽  
Vol 3 (3) ◽  
Author(s):  
Amrit Sagar ◽  
Christopher Nehme ◽  
Anil Saigal ◽  
Thomas P. James
Keyword(s):  
Finite Element ◽  
Yield Strength ◽  
Liquid Nitrogen ◽  
Material Properties ◽  
Room Temperature ◽  
Strain Hardening Exponent ◽  
Aspect Ratios ◽  
Strain Relationship ◽  
Relationship Of ◽  
Deform 3D

Abstract In pursuit of research to create a synthetic tissue scaffold by a micropunching process, material properties of polycaprolactone (PCL) in liquid nitrogen were determined experimentally and used for finite element modeling of cryogenic micropunching process. Specimens were prepared using injection molding and tested under compression to determine the stress–strain relationship of PCL below its glass transition temperature. Cryogenic conditions were maintained by keeping the PCL specimens submerged in liquid nitrogen throughout the loading cycle. Specimens of two different aspect ratios were used for testing. Yield strength, strength coefficient, and strain hardening exponent were determined for different specimen aspect ratios and extrapolated for the case with zero diameter to length ratio. Material properties were also determined at room temperature and compared against results available in the literature. Results demonstrate that PCL behaves in a brittle manner at cryogenic temperatures with more than ten times increase in Young's modulus from its value at room temperature. The results were used to predict punching forces for the design of microscale hole punching dies and for validation of a microscale hole punching model that was created with a commercially available finite element software package, deform 3D. The three parameters, yield strength, strength coefficient, and strain hardening exponent, used in Ludwik's equation to model flow stress of PCL in deform 3D were determined to be 94.8 MPa, 210 MPa, and 0.54, respectively. The predicted peak punching force from finite element simulations matched with experimentally determined punching force results.

Estimation of Stress Intensity Factors due To Welding Residual Stresses for Circumferentially Cracked Pipes

2012 ◽  
Author(s):  
Chang-Young Oh ◽  
Ji-Soo Kim ◽  
Yun-Jae Kim ◽  
Young-Jin Oh ◽  
Kyoungsoo Lee ◽  
...  
Keyword(s):  
Finite Element ◽  
Stress Intensity ◽  
Residual Stresses ◽  
Stress Intensity Factors ◽  
Finite Element Analyses ◽  
Intensity Factors ◽  
Crack Face ◽  
Simple Method ◽  
Weld Geometry ◽  
Nonlinear Stress

This paper proposes a simple method to estimate stress intensity factors due to welding residual stresses. In this study, finite element analyses for circumferentially cracked pipe are performed to calculate stress intensity factors. Four cracked geometries and two types of weld geometry are considered. KI-solutions for the nonlinear stress distribution on the crack face were determined in accordance with codes and standards. The results are compared with KI-solutions from finite element results. It is found that proposed simple method agrees well with FE results.

A Finite Element Method Study of Combined Hydraulic and Thermal Autofrettage Process

2017 ◽  
Vol 139 (4) ◽  
Author(s):  
Rajkumar Shufen ◽  
Uday S. Dixit
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Residual Stresses ◽  
Surface Temperature ◽  
Hydraulic Pressure ◽  
Simple Method ◽  
Inner Surface ◽  
Set Up ◽  
Element Method ◽  
Autofrettage Pressure

Autofrettage is a metal working process of inducing compressive residual stresses in the vicinity of the inner surface of a thick-walled cylindrical or spherical pressure vessel for increasing its pressure capacity, fatigue life, and stress-corrosion resistance. The hydraulic autofrettage is a class of autofrettage processes, in which the vessel is pressurized using high hydraulic pressure to cause the partial plastic deformation followed by unloading. Despite its popularity, the requirement of high pressure makes this process costly. On the other hand, the thermal autofrettage is a simple method, in which the residual stresses are set up by first maintaining a temperature difference across the thickness of the vessel and then cooling it to uniform temperature. However, the increase in the pressure carrying capacity in thermal autofrettage process is lesser than that in the hydraulic autofrettage. In the present work, a combined hydraulic and thermal autofrettage process of a thick-walled cylinder is studied using finite element method package ABAQUS® for aluminum and SS304 steel. The strain-hardening and Bauschinger effects are considered and found to play significant roles. The results show that the combined autofrettage can achieve desired increase in the pressure capacity of thick-walled cylinders with relatively small autofrettage pressure. For example, in a SS304 cylinder of wall-thickness ratio of 3, an autofrettage pressure of 150 MPa enhances the pressure capacity by 41%, but the same pressure with a 36 °C higher inner surface temperature than outer surface temperature can enhance the pressure capacity by 60%.

scholarly journals Extracting elastic constitutive parameters using the VFM within peridynamics

2019 ◽  
Author(s):  
Rolland Delorme ◽  
Patrick Diehl ◽  
Ilyass Tabiai ◽  
Louis Laberge Lebel ◽  
Martin Levesque
Keyword(s):  
Finite Element ◽  
Displacement Field ◽  
Material Properties ◽  
Noise Analysis ◽  
Image Correlation ◽  
Bending Test ◽  
Virtual Fields Method ◽  
Element Analysis ◽  
Constitutive Parameters

This paper implements the Virtual Fields Method within the ordinary state based peridynamic framework to identify material properties. The key equations derived in this approach are based on the principle of virtual works written under the ordinary state based peridynamic formalism for two-dimensional isotropic linear elasticity. In-house codes including a minimization process have also been developed to implement the method. A three-point bending test and two independent virtual fields arbitrarily chosen are used as a case study throughout the paper. The numerical validation of the virtual fields method has been performed on the case study by simulating the displacement field by finite element analysis. This field has been used to extract the elastic material properties and compared them to those used as input in the finite element model, showing the robustness of the approach. Noise analysis and the effect of the missing displacement fields on the specimen’s edges to simulate digital image correlation limitations have also been studied in the numerical part. This work focuses on pre-damage properties to demonstrate the feasibility of the method and provides a new tool for using full-field measurements within peridynamics with a reduced calculation time as there is no need to compute the displacement field. Future works will deal with damage properties which is the main strength of peridynamics.

Prediction of thermally induced postbuckling of clutch disks using the finite element method

2020 ◽  
pp. 135065012090197
Author(s):  
Zhuo Chen ◽  
Yun-Bo Yi ◽  
Ke Bao
Keyword(s):  
Finite Element ◽  
Material Properties ◽  
Temperature Fields ◽  
Frictional Heat ◽  
Temperature Dependent ◽  
Displacement Fields ◽  
Element Analysis ◽  
Nonlinear Buckling ◽  
Thermally Induced ◽  
Linear Buckling

Buckling and postbuckling of automotive clutch disks can be excited by the temperature fields caused by frictional heat generation during engagement of clutch systems. Linear and nonlinear buckling finite element analyses are performed to evaluate the thermal postbuckling of clutch metal disks. The dominant buckling modes are first obtained through performing linear buckling finite element analysis (FEA) analyses. The scaled displacement fields obtained from the linear buckling FEA analyses are added to the original geometries to generate the perturbed meshes. The postbuckling is then investigated by performing nonlinear buckling FEA analyses. The commercial FEA software ABAQUS is used in the current study. The effects of the temperature-dependent material properties are studied. It is concluded that the temperature dependence of material properties affects the postbuckling behaviors significantly.

A method for the measurement of residual stresses using a fracture mechanics approach

1989 ◽  
Vol 24 (1) ◽  
pp. 23-30 ◽  
Author(s):  
K J Kang ◽  
J H Song ◽  
Y Y Earmme
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Stress Distribution ◽  
Fracture Mechanics ◽  
Residual Stresses ◽  
Residual Stress Distribution ◽  
The State ◽  
Two Dimensional ◽  
Finite Element Analyses ◽  
Simple Method

A simple method for measuring residual stresses in a plate is described. In this method residual stresses are evaluated using a fracture mechanics approach, that is, the strains or displacements measured at a point on the edge of a plate as a crack is introduced and extended from the edge are used to deduce the state of stresses that existed in the uncracked plate. Through finite element analyses and experiments this method is shown to be valid and effective for measuring the two-dimensional residual stress distribution of a welded plate.

Finite element parametric study of the split sleeve cold expansion on residual stresses and pulling force

2021 ◽  
pp. 095440622110255
Author(s):  
Mithun K Dey ◽  
Dave Kim ◽  
Hua Tan
Keyword(s):  
Finite Element ◽  
Yield Strength ◽  
Residual Stresses ◽  
Parametric Study ◽  
Industrial Applications ◽  
Published Data ◽  
Fe Model ◽  
Residual Stress Field ◽  
Cold Expansion ◽  
Pulling Force

Split sleeve cold expansion (SSCE) is a crucial cost-effective process to improve the fatigue life of metallic structures with holes in the aerospace industry. In this study, the effects of the workpiece material’s yield strength (290.9 MPa to 377.8 MPa) and the applied SSCE expansion percentage (3.330% to 4.377%) on mandrel pulling force and residual stresses were investigated numerically for aluminum 2024-T351. A three-dimensional finite element (FE) model was developed to simulate the SSCE process using a commercial FE software, ABAQUS. The model geometries, material non-linearities, and contact conditions were adopted according to aerospace industrial applications’ standards. After the numerical model was validated with the published data, a parametric study with variable material properties and expansion percentage was conducted using the FE model. Our parametric study shows that an increase in both the Al workpiece’s yield strength and SSCE expansion percentage can improve the induced residual stresses in the hoop direction around the cold expanded hole; however, the workpiece’s yield strength has a higher impact on the residual stress field. The in-process pulling force during the SSCE process increases with increasing workpiece yield strength and expansion percentage.

The Importance of Intrinsic Damage Properties to Bone Fragility: A Finite Element Study

2012 ◽  
Vol 135 (1) ◽  
Author(s):  
M. R. Hardisty ◽  
R. Zauel ◽  
S. M. Stover ◽  
D. P. Fyhrie
Keyword(s):  
Finite Element ◽  
Yield Strength ◽  
Trabecular Bone ◽  
Bone Tissue ◽  
Material Properties ◽  
Mechanical Energy ◽  
Bone Fragility ◽  
Intrinsic Properties ◽  
Microdamage Accumulation ◽  
Apparent Level

As the average age of the population has increased, the incidence of age-related bone fracture has also increased. While some of the increase of fracture incidence with age is related to loss of bone mass, a significant part of the risk is unexplained and may be caused by changes in intrinsic material properties of the hard tissue. This investigation focused on understanding how changes to the intrinsic damage properties affect bone fragility. We hypothesized that the intrinsic (μm) damage properties of bone tissue strongly and nonlinearly affect mechanical behavior at the apparent (whole tissue, cm) level. The importance of intrinsic properties on the apparent level behavior of trabecular bone tissue was investigated using voxel based finite element analysis. Trabecular bone cores from human T12 vertebrae were scanned using microcomputed tomography (μCT) and the images used to build nonlinear finite element models. Isotropic and initially homogenous material properties were used for all elements. The elastic modulus (Ei) of individual elements was reduced with a secant damage rule relating only principal tensile tissue strain to modulus damage. Apparent level resistance to fracture as a function of changes in the intrinsic damage properties was measured using the mechanical energy to failure per unit volume (apparent toughness modulus, Wa) and the apparent yield strength (σay, calculated using the 0.2% offset). Intrinsic damage properties had a profound nonlinear effect on the apparent tissue level mechanical response. Intrinsic level failure occurs prior to apparent yield strength (σay). Apparent yield strength (σay) and toughness vary strongly (1200% and 400%, respectively) with relatively small changes in the intrinsic damage behavior. The range of apparent maximum stresses predicted by the models was consistent with those measured experimentally for these trabecular bone cores from the experimental axial compressive loading (experimental: σmax = 3.0–4.3 MPa; modeling: σmax = 2–16 MPa). This finding differs significantly from previous studies based on nondamaging intrinsic material models. Further observations were that this intrinsic damage model reproduced important experimental apparent level behaviors including softening after peak load, microdamage accumulation before apparent yield (0.2% offset), unload softening, and sensitivity of the apparent level mechanical properties to variability of the intrinsic properties.

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