ELASTO-PLASTIC BUCKLING OF PRESTRESSED ARCHES

2002 ◽  
Vol 02 (03) ◽  
pp. 295-313
Author(s):  
AMIR MIRMIRAN ◽  
AMDE M. AMDE ◽  
ZEFANG XU
Keyword(s):  
Yield Strength ◽  
Strain Hardening ◽  
Beam Element ◽  
Fabrication Technique ◽  
Linear Strain ◽  
Plastic Buckling ◽  
Buckling Mode ◽  
Hardening Material ◽  
Straight Beam ◽  
Support Conditions

Intentional buckling as a fabrication technique for arch frameworks results in prestrains at every section of the arch, which in turn affect its strength and stability. A nonlinear corotational straight beam element with elastic, linear strain hardening material has been developed to study the elasto-plastic buckling of prestressed arches. The study indicates that for prestressed arches there is an interdependence between the slenderness and steepness ratios of the arch with the ratio of prestresses to the yield strength of the material, all of which control the magnitude and shape of buckling mode. While steeper arches are generally more stable in their elastic range, the effect of steepness ratio is reduced as the prestress exceeds 55% of the yield strength. Effects of loading and support conditions have also been considered. Although fixed supports result in more stable arches, their effectiveness depends on the steepness ratio and the level of prestresses. Finally, the effect of strain hardening on the plastic buckling of the arch is more pronounced for lower values of the plastic tangent modulus.

Thermal Ratcheting of a Beam Element Having an Idealized Bauschinger Effect

1976 ◽  
Vol 98 (3) ◽  
pp. 264-271 ◽  
Author(s):  
T. M. Mulcahy
Keyword(s):  
Strain Hardening ◽  
Temperature Variation ◽  
Bauschinger Effect ◽  
Rectangular Cross Section ◽  
Beam Element ◽  
Operating Conditions ◽  
Hardening Material ◽  
Linear Temperature ◽  
Thermal Ratcheting ◽  
Breeder Reactors

Thermal ratcheting has been analytically investigated for a beam element subjected to a linear temperature variation across its solid rectangular cross section. A linear strain-hardening material response exhibiting an idealized Bauschinger effect was assumed. Formulas are given for the associated strain accumulation which are valid over a large range of strain hardening, temperature variation, temperature cycles, and axial load. Specific results are tabulated for the materials and operating conditions typically associated with liquid metal breeder reactors.

A General Solution for the Elastoplastic Thermal Stresses in a Strain-Hardening Plate With Arbitrary Material Properties

1962 ◽  
Vol 29 (1) ◽  
pp. 151-158 ◽  
Author(s):  
A. Mendelson ◽  
S. W. Spero
Keyword(s):  
Thermal Expansion ◽  
General Solution ◽  
Strain Hardening ◽  
Material Properties ◽  
Thermal Stresses ◽  
Coefficient Of Thermal Expansion ◽  
Stress And Strain ◽  
Linear Strain ◽  
Hardening Material ◽  
General Method

A general method is presented for obtaining the elastoplastic stress and strain distributions in a thermally stressed plate of a strain-hardening material with temperature-varying modulus, yield point, and coefficient of thermal expansion. It is shown that for linear strain-hardening the solution can often be obtained in closed form. It is indicated that the error due to neglecting strain-hardening may sometimes be appreciable. The assumption that the total strain remains the same as that computed elastically (strain invariance) often leads to smaller errors than the neglect of strain-hardening.

Determination of Expanding Pressure of Hydraulically Expanded Tube-to-Tubesheet Joint

2010 ◽  
Vol 97-101 ◽  
pp. 2898-2902 ◽  
Author(s):  
Xie Tian ◽  
Xiao Ping Huang ◽  
Zhi Yong Fu
Keyword(s):  
Strain Hardening ◽  
Contact Pressure ◽  
Material Model ◽  
Linear Strain ◽  
Element Analysis ◽  
Hardening Material ◽  
Expansion Pressure ◽  
General Strain ◽  
Special Case

It is very important to determine the expansion pressure or residual contact pressure of tube-to-tubesheet joint. The expansion pressure and the residual contact pressure are affected by the geometry, material mechanical properties of the tube and tubesheet. In the basic theory of calculating the residual contact pressure of tube-to-tubesheet joints, the elastic-perfectly material is assumed. Because of the strain-hardening of the materials, linear strain-hardening or power strain-hardening were adopted in some analyzing models of the hydraulically expanded tube-to-tubesheet joint. In this paper, a general strain-hardening material model is adopted and an analytical model is proposed and validated by finite element analysis results. The elastic-perfectly model, linear strain-hardening model or power strain-hardening can be the special case of the present model.

Elastic and Elastic-Plastic Buckling of Internally Pressurized 2:1 Ellipsoidal Shells

1978 ◽  
Vol 100 (4) ◽  
pp. 335-343 ◽  
Author(s):  
G. D. Galletly
Keyword(s):  
Strain Hardening ◽  
Linear Strain ◽  
Plastic Buckling ◽  
Elastic Plastic

Elastic and elastic-plastic buckling pressures for internally-pressurized 2:1 ellipsoidal shells with diameter-thickness ratios in the range 750 < D/t < 1500 are given in the paper. The effects of σyp, E and linear strain hardening on the buckling pressures were investigated and both flow and deformation theories utilized. Some experimental/theoretical correlations are also given. The elastic pcr’s differ from some which have been published recently and the elastic-plastic pcr’s are believed to be new. For steel shells, flow and deformation theories sometimes gave contradictory buckling predictions but this was not the case with the aluminum shells which were investigated.

MANUFACTURE INVESTIGATION OF CARTRIDGE WITH BOTTOM-MOST PART FLANGE BY DIRECT EXTRUSION WITH COUNTERPUNCH. REPORT 18. EXPERIMENTAL CHECK OF THEORETICAL RESULTS FOR DIFFERENT HOLLOW RADIUSES AND BOTTOM-MOST PART THICKNESSES

2020 ◽  
Vol 0 (9) ◽  
pp. 16-23
Author(s):  
A. L. Vorontsov ◽  
◽  
I. A. Nikiforov ◽  
Keyword(s):  
Strain Hardening ◽  
Theoretical Calculations ◽  
High Accuracy ◽  
Geometric Parameters ◽  
Strength Characteristics ◽  
Experimental Check ◽  
Hardening Material ◽  
Direct Extrusion ◽  
Theoretical Results

The results of an experimental check of the obtained theoretical formulae allowing us to determine the most important parameters of extrusion cartridges with a counterpunch for different hollow radiuses and bottom-most part thicknesses are presented. Characteristics of used tools, geometric parameters of extrusion experiments, strength characteristics of deformed materials and lubricants are described in detail. Both strain-hardening material and strain-unhardening material were studied. Methodology of the theoretical calculations is demonstrated in detail. High accuracy of the obtained design formulae was confirmed.

Influencing Factors for Improving Accuracy in Prediction of Stress Corrosion Crack Growth Rate in Boiling Water Reactor Operational Condition: Part 1—Prediction of SCC Growth Rate in Terms of Vickers Hardness

2010 ◽  
Author(s):  
Yoichi Takeda ◽  
Zhanpeng Lu ◽  
Takeshi Adachi ◽  
Qunjia Peng ◽  
Jiro Kuniya ◽  
...  
Keyword(s):  
Growth Rate ◽  
Stainless Steel ◽  
Yield Strength ◽  
Strain Hardening ◽  
Crack Growth ◽  
Vickers Hardness ◽  
316L Stainless Steel ◽  
Strain Hardening Exponent ◽  
Theoretical Formulation ◽  
Prediction Curve

It is known that stress corrosion cracking (SCC) found in the operational power plants show complex cracking behaviors and it’s resulted in complex crack shape e.g. crack branching and its uneven crack front. For the cracking near the weldment, this is due to crack penetrated along the complex distribution of residual stress and strain hardened area. In this investigation, in order to advance the accuracy for crack growth prediction with considering such complex fields, theoretical formulation for SCC growth was further modified. Hardness of the materials, which is a measureable parameter even in operational power plant, was focused on to reflect strain hardening of the component like heat affected zone of the weldments. The theoretical formulation for SCC growth has terms with yield strength of the material and strain hardening exponent to describe crack tip strain rate. Strain hardening was simulated by cross rolling with the range of 4 – 32% as thickness reduction. Correlation between yield strength, strain hardening exponent at 288°C and Vickers hardness was obtained by means of tensile tests and hardness tests on 316L stainless steel. It was observed that a monotonic increase in Vickers hardness and yield strength with degree of reduction in thickness worked by cross rolling. Relationship between Vickers hardness and yield strength was found to have linear correlation. Further confirmation was made by plotting the reported mechanical properties data in terms of Vickers hardness. In addition, linear relationship was found between yield strength and strain hardening exponent. These relationships were introduced into SCC theoretical formulation and a SCC growth rate prediction curve in terms of Vickers hardness was proposed. SCC crack growth evaluation tests with selected work hardened 316L stainless steel were performed in oxygenated pure water environment at 288°C to confirm the predictability of the formulation. The prediction curve had a good agreement with available literature data as well as obtained crack growth rates in the hardness range of 140–300HV which was likely expected one in weld HAZ.

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