The ASME Code and 3D Stress Evaluation

1991 ◽  
Vol 113 (4) ◽  
pp. 481-487 ◽  
Author(s):  
J. L. Hechmer ◽  
G. L. Hollinger
Keyword(s):  
Shell Theory ◽  
Failure Modes ◽  
Three Dimensional ◽  
Stress Distributions ◽  
Modes Of Failure ◽  
Failure Assessment ◽  
Asme Code ◽  
Dimensional Finite Element ◽  
Bending Stresses ◽  
Three Dimensional Finite Element

The ASME Code [1] identifies the modes of failure that must be addressed to ensure acceptable pressure vessel designs. The failure modes addressed in this paper are precluded by limits on the primary and primary plus secondary stress. Both involve the transition from elasticity to plasticity. Their evaluation requires the computation of membrane and bending stresses (the linearized stresses). The original techniques for evaluating the limits were based on beam and shell theory. Since beam and shell theory were the basis of the then-current tools, the transition from analysis results to failure assessment was straightforward. With the advent of finite elements (FE), the transition from the stress distribution to the failure modes requires a different path. For three-dimensional finite element (3D FE), the path is obscure. Since the development of FE, the ASME Code has made no additions to clarify the correlations between FE stress distributions and the failure modes. The authors believe that the Code should provide guidance in this area.

Finite Element Analysis of Perforated Plates Containing Triangular Penetration Patterns of 5 and 10 Percent Ligament Efficiency

1975 ◽  
Vol 97 (3) ◽  
pp. 199-205 ◽  
Author(s):  
D. P. Jones
Keyword(s):  
Finite Element ◽  
Three Dimensional ◽  
Peak Stress ◽  
Stress Distributions ◽  
Element Analysis ◽  
Perforated Plates ◽  
Vessel Closure ◽  
Asme Code ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

Two- and three-dimensional finite element models were used to determine elastic stress distributions in plate ligaments for various in-plane, bending, and thermal loadings. Plates containing triangular penetration patterns of 5 and 10 percent ligament efficiency were analyzed as well as the example of a circular plate containing a single centrally placed hole subjected to step change in temperature on one surface. Detailed descriptions of boundary conditions are given with the results presented in terms of stresses important in tubesheet and vessel closure design considerations. Results show that the minimum ligament section of the perforated region need not be the critically stressed cross section as is currently assumed in the ASME Boiler and Pressure Vessel Code. Further, a thermal shock ΔT applied to the surface of a perforated region will result in a maximum peak stress of EαΔT/(1−ν) and may be significantly lower than the thermal skin stress calculated by the ASME Code procedures.

Overstraining of flush plain cross-bored cylinders

2004 ◽  
Vol 218 (2) ◽  
pp. 143-153 ◽  
Author(s):  
J M Kihiu ◽  
G O Rading ◽  
S M Mutuli
Keyword(s):  
Finite Element Method ◽  
Yield Criterion ◽  
Three Dimensional ◽  
Yield Condition ◽  
Solution Technique ◽  
Stress Distributions ◽  
Dimensional Finite Element ◽  
Von Mises ◽  
Three Dimensional Finite Element ◽  
Incremental Theory Of Plasticity

A three-dimensional finite element method computer program was developed to establish the elastic-plastic, residual and service stress distributions in thick-walled cylinders with flush and non-protruding plain cross bores under internal pressure. The displacement formulation and eight-noded brick isoparametric elements were used. The incremental theory of plasticity with a 5 per cent yield condition (an element is assumed to have yielded when the effective stress is within 5 per cent of the material yield stress) and von Mises yield criterion were assumed. The frontal solution technique was used. The incipient yield pressure and the pressure resulting in a 0.3 per cent overstrain ratio were established for various cylinder thickness ratios and cross bore-main bore radius ratios. For a thickness ratio of 2.25 and a cross bore-main bore radius ratio of 0.1, the stresses were determined for varying overstrain and an optimum overstrain ratio of 37 per cent was established. To find the accuracy of the results, the more stringent yield condition of 0.5 per cent was also considered. The benefits of autofrettage were presented and alternative autofrettage and yield condition procedures proposed.

Cyclic and Residual Stresses Generated in the UHMWPE Component of Total Knee Replacements During the Walking Cycle

1999 ◽  
Author(s):  
Raghu N. Natarajan
Keyword(s):  
Residual Stresses ◽  
Failure Modes ◽  
Contact Region ◽  
Three Dimensional ◽  
Knee Kinematics ◽  
Element Model ◽  
Clear Understanding ◽  
Dimensional Finite Element ◽  
Total Knee ◽  
Three Dimensional Finite Element

Abstract Fatigue due to cyclic stresses is one of the predominant failure modes seen in retrieved tibial polyethylene components. There is no clear understanding of the influence of knee kinematics on wear seen in retrieved samples. Magnitude, direction and location of the contact load at the tibial surface were taken from the measurement obtained from gait analysis of a patient with a total knee replacement and was input into a three dimensional finite element model of a tibial component. The analyses showed that stress fluctuations and stress reversals occur both on the surface and just below the surface in the posterior region of the component. Residual stresses were produced due to plastic deformation in the posterior contact region of the component.

Residual Stress Prediction for Non-Axisymmetric Vessel Penetration Welds

2008 ◽  
Author(s):  
Kazuo Ogawa ◽  
Nobuyoshi Yanagida ◽  
Koichi Saito
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Three Dimensional ◽  
Measurement Data ◽  
Fe Model ◽  
Stress Distributions ◽  
Dimensional Finite Element ◽  
Stress Prediction ◽  
Three Dimensional Finite Element ◽  
Good Agreement

Residual stress distribution in an oblique nozzle jointed to a vessel with J-groove welds was analyzed using a three-dimensional finite element method. All welding passes were considered in a 180-degree finite element (FE) model with symmetry. Temperature and stress were modeled for simultaneous bead laying. To determine residual stress distributions at the welds experimentally, a mock-up specimen was manufactured. The analytical results show good agreement with the experimental measurement data, indicating that FE modeling is valid.

Three-Dimensional Finite Element Analysis of Rigid Flanged Shaft Coupling Subjected to Twisting Moment

2013 ◽  
Author(s):  
Koichi Okayama ◽  
Toshimichi Fukuoka
Keyword(s):  
Friction Force ◽  
Shear Force ◽  
Three Dimensional ◽  
Bending Moment ◽  
Shaft Length ◽  
Element Analysis ◽  
Bolt Stress ◽  
Dimensional Finite Element ◽  
Bending Stresses ◽  
Three Dimensional Finite Element

A reamer bolt is commonly used when clamping a rigid shaft coupling subjected to large shear force. Although some joint design procedures assume that the applied shear force transmits only through the reamer surface, it is also supported by the friction force on the contact surfaces. Accordingly, to design the coupling clamped by reamer bolts, it is important to evaluate the ratio of the shear forces supported by the reamer surface and the friction force, which is defined as shear force transfer ratio (SFTR) here. In this study, distributions of SFTR and the bending stresses along the reamer surface are analyzed by three-dimensional FEM, focusing on the effects of the fit between the reamer bolt and bolt hole, the scatter of initial bolt stress and the misalignment of the connecting shafts. Numerical results quantitatively clarify how the amounts of the SFTR and the bending stresses as the friction coefficients, the fit and the magnitude of misalignment are changed. As for an offset misalignment, it is found that its effect on the bending moment generated in the shaft body is negligibly small, if the offset between two shafts in radial direction is less than 10mm which is 1% of the total shaft length.

A Three-Dimensional Finite Element Evaluation of a Destructive Experimental Method for Determining Through-Thickness Residual Stresses in Girth Welded Pipes

1986 ◽  
Vol 108 (2) ◽  
pp. 99-106 ◽  
Author(s):  
E. F. Rybicki ◽  
J. R. Shadley
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Experimental Method ◽  
Three Dimensional ◽  
Element Model ◽  
Stress Distributions ◽  
Reference Stress ◽  
Improvement Process ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

The accuracy of a destructive, experimental method for the evaluation of through-thickness residual stress distributions is investigated. The application of the method is to a welded pipe that has been subjected to a residual stress improvement process. The residual stress improvement process introduces gradients in the stress distribution. The question of interest is how well the back-computation method used to interpret the experimental data represents the residual stress distribution for this type of stress profile. To address this question, a finite element model was used to provide a reference stress solution for comparison with the back-computation results of the experimental method. Three-dimensional finite element stress analyses were also conducted to simulate the cutting steps of the destructive laboratory procedure. The residual stress distributions obtained by the back-computation procedure were then compared with the reference stress solutions provided by the finite element model. The comparisons show agreement and indicate that good results can be expected from the experimental method when it is applied to a pipe that has been subjected to a residual stress improvement process, provided that the axial gradient of stress is not too large.

Ballistic Impact Response of Composite Systems

2006 ◽  
Author(s):  
Abdalla Elbella ◽  
Santosh Kumar Saride
Keyword(s):  
Failure Modes ◽  
Impact Resistance ◽  
Three Dimensional ◽  
Laminated Composite ◽  
Ballistic Limit ◽  
Dissipation Energy ◽  
Composite Systems ◽  
Rigid Projectile ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

Composite materials are widely used in many engineering applications and are an attractive for armor design because of their increased high toughness, impact resistance, stiffness, and strength-to-weight ratios and the ability to tailor their designs to applications. In this paper, numerical simulation of impact on composites is being performed to predict ballistic limit velocities and evaluate the delamination behavior of different composite systems. The normal impact and penetration of blunt rigid projectile on laminated composite targets was developed to estimate the velocity for which the projectile has complete penetration, the ballistic limits and energy absorbed while perforating a given piece of armor. A non-linear, explicit, three dimensional finite element commercial code (ABAQUS) is used to simulate the response of armor targets at V50 impact velocities. The armor test panel is modeled as a multi-layered laminated plate with different composite systems, thickness, and stacking sequence. The three failure modes that represent the three stages of the penetration process namely transverse shear, tensile fiber breakage, and delamination are identified. The ballistic limit curves for different materials, thickness, and orientations are determined. The target interlaminar stress distributions along the thickness are graphically represented. Strain energy, Plastic dissipation and Kinetic dissipation energy curves for the whole model were obtained including thickness effects.

Effect of truck position and multiple truck loading on response of long-span metal culverts

2014 ◽  
Vol 51 (2) ◽  
pp. 196-207 ◽  
Author(s):  
Tamer M. Elshimi ◽  
Richard W.I. Brachman ◽  
Ian D. Moore
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Shell Theory ◽  
Orthotropic Shell ◽  
Three Dimensional ◽  
Element Analysis ◽  
Long Span ◽  
Dimensional Finite Element ◽  
Current Design ◽  
Three Dimensional Finite Element

Long-span metal culverts have been used for almost 50 years as an economical alternative to short-span bridges. Current design methods are based on two-dimensional finite element analysis using beam theory to represent the structure, or three-dimensional analysis employing orthotropic shell theory. However, neither analysis has been used to investigate the most critical position for trucks at the surface of long-span metal culverts. This paper shows results of three-dimensional finite element analysis, employing orthotropic shell theory and explicitly modeling the geometry of corrugated plates for a specific box culvert tested using a fully loaded dump truck. The analysis was then extended to study the effect of truck position on the response of long-span box and arch culverts. The finite element models, employing orthotropic shell theory and explicitly modeling the geometry of corrugated plates, successfully produced the behaviour of the culvert under truck loading for different truck positions. Culvert deformations were calculated within 7%–13% of the measured values at different locations. The bending moment at the crown was within 4%–17% of the values calculated using the measured strains. If three-dimensional finite element analysis is used to design these culverts, two design trucks should be considered (current design considers a single design truck). The highest moment or thrust is obtained when the truck tandem axles are located above the crown of the culvert.

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