Three “Neutral” Loading Tests

1956 ◽  
Vol 23 (4) ◽  
pp. 497-502
Author(s):  
S. S. Gill
Keyword(s):  
Shear Stress ◽  
Plastic Strain ◽  
Internal Pressure ◽  
Yield Criterion ◽  
Maximum Shear Stress ◽  
Loading Path ◽  
Plastic Strain Increment ◽  
Octahedral Shear Stress ◽  
Loading Tests ◽  
Von Mises

Abstract Three tests have been carried out using hollow tubes of alpha brass subjected to combined torsion and internal pressure. An initial torque was applied sufficient to cause plastic deformation, and then the torque was decreased and the internal pressure increased to keep the octahedral shear stress constant in two tests and the maximum shear stress constant in the third test. These loading paths were chosen because they would be neutral loading if the material obeyed the von Mises-Hencky or Guest yield criterion, respectively. Shear strain, axial, and circumferential strain were measured. All three tests gave some plastic strain during the “neutral” loading, but the constant maximum shear-stress loading gave much larger plastic strains than the constant octahedral stress loading. The plastic-strain increment vectors have been plotted to illustrate their direction relative to the loading path.

Design Equation for Minimum Required Thickness of a Cylindrical Shell Subject to Internal Pressure Based on Von Mises Criterion

2019 ◽  
Author(s):  
James Lu ◽  
Barry Millet ◽  
Kenneth Kirkpatrick ◽  
Bryan Mosher
Keyword(s):  
Cylindrical Shell ◽  
Internal Pressure ◽  
Yield Criterion ◽  
Design Equation ◽  
Shell Wall ◽  
Section Viii ◽  
Von Mises Yield Criterion ◽  
Von Mises ◽  
Division 2 ◽  
Shell Wall Thickness

Abstract Design equation (4.3.1) for the minimum required thickness of a cylindrical shell subjected to internal pressure in Part 4 “design by rule (DBR)” of the ASME Boiler and Pressure Vessel Code, Section VIII, Division 2 [1] is based on the Tresca Yield Criterion, while design by analysis (DBA) in Part 5 of the Division 2 Code is based on the von Mises Yield Criterion. According to ASME PTB-1 “ASME Section VIII – Division 2 Criteria and Commentary”, the difference in results is about 15% due to use of the two different criteria. Although the von Mises Yield Criterion will result in a shell wall thickness less than that from Tresca Yield Criterion, Part 4 (DBR) of ASME Division 2 adopts the latter for a more convenient design equation. To use the von Mises Criterion in lieu of Tresca to reduce shell wall thickness, one has to follow DBA rules in Part 5 of Division 2, which typically requires detailed numeric analysis performed by experienced stress analysts. This paper proposes a simple design equation for the minimum required thickness of a cylindrical shell subjected to internal pressure based on the von Mises Yield Criterion. The equation is suitable for both thin and thick cylindrical shells. Calculation results from the equation are validated by results from limit load analyses in accordance with Part 5 of ASME Division 2 Code.

Mobilization of Fully Plastic Moment Capacity for Pressurized Pipes

1999 ◽  
Vol 121 (4) ◽  
pp. 237-241 ◽  
Author(s):  
M. Mohareb ◽  
D. W. Murray
Keyword(s):  
Internal Pressure ◽  
Axial Force ◽  
Yield Criterion ◽  
Axial Loading ◽  
Experimental Results ◽  
Moment Capacity ◽  
Interaction Diagram ◽  
Von Mises ◽  
Force Pressure ◽  
Good Agreement

An analytical expression is derived for the prediction of fully plastic moment capacity of pipes subjected to axial loading and internal pressure. The expression is based on the von Mises yield criterion. The expression predicts pipe moment capacities that are in good agreement with full-scale experimental results. A universal nondimensional moment versus effective axial force-pressure interaction diagram is developed for the design of elevated pipe lines.

scholarly journals Anisotropic Yield Criterion under the Maximum Shear Stress Theory

1970 ◽  
Vol 13 (61) ◽  
pp. 825-836
Author(s):  
Hisashi IGAKI ◽  
Masakatsu SUGIMOTO ◽  
Koichi SAITO
Keyword(s):  
Shear Stress ◽  
Yield Criterion ◽  
Maximum Shear Stress ◽  
Stress Theory ◽  
Anisotropic Yield Criterion

Poisson Ratio Effects on the Von Mises and Maximum Shear Stresses in Cylindrical Contacts

2005 ◽  
Author(s):  
Itzhak Green
Keyword(s):  
Shear Stress ◽  
Poisson Ratio ◽  
Unit Length ◽  
Maximum Shear Stress ◽  
Critical Force ◽  
Von Mises Stress ◽  
Maximum Pressure ◽  
Shear Stresses ◽  
Wide Range ◽  
Von Mises

This work determines the location of the greatest elastic distress in cylindrical contacts based upon the distortion energy and the maximum shear stress theories. The ratios between the maximum pressure, the von Mises stress, and the maximum shear stress are determined and fitted by empirical formulations for a wide range of Poisson ratios, which represent material compressibility. Some similarities exist between cylindrical and spherical contacts, where for many metallic materials the maximum von Mises or shear stresses emerge beneath the surface. However, if any of the bodies in contact is excessively compressible the maximum von Mises stress appears at the surface. That transitional Poisson ratio is found. The critical force per unit length that causes yielding onset, along with its corresponding interference and half-width contact are derived.

scholarly journals The Effect of Combined Tensile-Torsional Loading Path on the Stress/Strain States of Thin-Walled Circular Tubes

2020 ◽  
Vol 2020 ◽  
pp. 1-16
Author(s):  
Yue Gao ◽  
Fei Shao ◽  
Qian Xu ◽  
Linyue Bai ◽  
Qingna Ma ◽  
...  
Keyword(s):  
Strain Path ◽  
Yield Criterion ◽  
Stress Path ◽  
Loading Path ◽  
Torsional Loading ◽  
Linear Hardening ◽  
Circular Tubes ◽  
Thin Walled ◽  
Von Mises Yield Criterion ◽  
Von Mises

In this paper, an elastoplastic analysis model of thin-walled circular tubes under the combined action of axial force and torque is discussed. Based on the von Mises yield criterion and the assumption of isotropic linear hardening, the methods of stress path and strain path loading are analyzed to study the effect of combined tensile-torsional loading path on thin-walled circular tubes. A finite element model is used to analyze the loading path effect on thin-walled circular tubes. A series of tensile and torsional tests are also carried out on 304 stainless steel thin-walled circular tubes using a universal testing machine. In addition, the consistency of the selected material with the von Mises yield criterion, the assumption of isotropic linear hardening, and other classical elastoplastic mechanics are verified. The theoretical calculation results, the numerical analysis results, and the experimental test results are analyzed and compared. The “primary effect” influenced by the stress path and the “recency effect” affected by the strain path are proved, and their application prospects are discussed. The influence of tensile-torsional loading path on the final stress and strain states of thin-walled circular tubes after entering the plastic deformation stage is concretely demonstrated, facilitating the understanding of the principles of the aforementioned two effects. The investigation for a general principle concerning the effect of loading history on the mechanical behavior of engineering materials, based on the classical plastic mechanics, has an important theoretical significance. It is of great theoretical importance for advancements in plastic yield theory and the establishment of more accurate loading conditions suitable for specific materials in engineering practice.

Biezeno Pressure Vessel Heads

1956 ◽  
Vol 23 (4) ◽  
pp. 642-645
Author(s):  
R. A. Struble
Keyword(s):  
Shear Stress ◽  
Internal Pressure ◽  
Pressure Vessel ◽  
Maximum Shear Stress ◽  
Head Shape ◽  
Thin Walled ◽  
Constant Maximum

Abstract The equation of thin-walled pressure vessel heads with constant maximum shear stress throughout is derived. Such heads, used on cylindrical vessels with uniform internal pressure, were first conceived by Biezeno in 1922 who gave a semigraphical prescription for determining the head shape.

Bending Die Design for a Pre-Formed Sheet Metal with a Golden Finger Feature

2008 ◽  
Vol 594 ◽  
pp. 51-56
Author(s):  
Jinn Jong Sheu ◽  
Sheng Hao Fang
Keyword(s):  
Shear Stress ◽  
Material Flow ◽  
Quality Index ◽  
Design Method ◽  
Maximum Shear Stress ◽  
Die Design ◽  
Von Mises Stress ◽  
Design Parameters ◽  
Profile Design ◽  
Von Mises

In this paper, authors proposed an effective quality index of bending operation and a new punch profile design method to prevent defects. The proposed quality index is presented in terms of distance of fracture location with respect to the topmost plane of blank, the maximum von Mises stress, and the maximum shear stress. The Taguchi method with L18 orthogonal array was adopted to evaluate the effects of design parameters and find out the optimum design of punch profile. A new punch feature called “golden finger” was proposed to control the material flow and move the fracture defects out of the trimming line. The results of this study had demonstrated the optimum die design can be achieved with the proposed golden finger feature to obtain a sound product.

Multidisciplinary Design Optimization of the Composite Cooling Structure for Nickel-based Alloy Turbine Blade

2019 ◽  
Vol 0 (0) ◽  
Author(s):  
Xiaoru Qian ◽  
Peigang Yan ◽  
Wanjin Han
Keyword(s):  
Shear Stress ◽  
Flow Field ◽  
Turbine Blade ◽  
Maximum Shear Stress ◽  
Three Dimensional ◽  
Leading Edge ◽  
Suction Side ◽  
Structure Design ◽  
Von Mises Stress ◽  
Von Mises

Abstract A designed method, multidisciplinary coupling computation and multiobjective optimization, has been established for the composite cooling structure of heavy gas turbine blade manufactured with a directionally solidified Ni-based superalloy. The method combines the one-dimensional fluid network gas-thermal coupling computation, three-dimensional flow field coupled with solid stress field, and anisotropic stress calculation based on finite deformation crystal slip. The temperature, flow field, Von-Mises stress and maximum resolved shear stress of the blade before and after optimization were analyzed. The results show that the optimized blade has lower maximum blade temperature, a more uniform temperature distribution, a lower flow resistance of the coolant channel at the leading edge than that of the original blade. The maximum Von-Mises stress of the optimized blade increases by 10.05 % more than the original blade. The maximum shear stress on the suction side and the pressure surface of the optimized blade are improved and slightly deteriorated compared with that of the original blade, respectively. The corresponding relationship of the maximum shear stress distribution with the local temperature gradient reveals further space for the improvement of the composite cooling structure. This paper has a particular guiding significance for the cooling structure design of the turbine blade.

Effects of the Yield Criterion on Predicted Fracture Responses of Pipelines Subjected to Large Plastic Deformation With and Without Internal Pressure

2010 ◽  
Author(s):  
Alexandre Kane ◽  
Erling O̸stby ◽  
Odd-Geir Lademo ◽  
Torodd Berstad ◽  
Odd Sture Hopperstad
Keyword(s):  
Internal Pressure ◽  
Yield Surface ◽  
Structural Integrity ◽  
Yield Criterion ◽  
Surface Shape ◽  
Crack Tip Opening Displacement ◽  
Opening Displacement ◽  
Safety Level ◽  
Standard Material ◽  
Von Mises

The structural integrity of offshore pipelines is of vital importance for safe oil and gas transport. To ensure the required safety level, non-linear Finite Element (FE) analyses are necessary to perform fracture assessment of pipes under various, realistic loading conditions. Many standard material models, as found in commercial FE codes, pre-suppose the yield criterion of von Mises. This choice provides in many cases reasonable accuracy, certainty and engineering designs, but for some materials and application areas, it is much too inaccurate. In this work, 3D elastic–plastic FE simulations of pipes with internal surface cracks have been carried out. The aim of the work is to evaluate the influence of the yield criterion on the predicted fracture response. Analyses are performed on pipes loaded in tension, with and without internal pressure. The model shows that the yield surface shape may have a significant effect on the predicted evolution of Crack Tip Opening Displacement (CTOD). If the internal pressure is weak, a reduction in strain capacity is observed when the yield surface shape is varied from the rounded von Mises towards the cornered Tresca-like yield surface.

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