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thick-walled-vessels
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Evaluation of the optimum pre-stressing pressure and wall thickness determination of thick-walled spherical vessels under internal pressure
, Article Journal of the Franklin Institute ; Volume 344, Issue 5 , 2007 , Pages 439-451 ; 00160032 (ISSN) ; Darijani, H ; Naghdabadi, R ; Sharif University of Technology
2007
Abstract
In the present study, in the first part for a spherical vessel with known dimensions and working pressure, two methods of hoop and equivalent stress optimization across the wall thickness are employed to determine the best autofrettage pressure. In the next part for a predefined working pressure the minimum wall thickness of the vessel is calculated using two other design criteria i.e. (A) optimizing the hoop stress, and (B) assuming a suitable percent for the penetration of yielding within the wall thickness. Finally, the optimum thickness and the necessary strengthening pressure are extracted and different plots are introduced for different types of structural materials under different...
Design of spherical vessels under steady-state thermal loading using thermo-elasto-plastic concept
, Article International Journal of Pressure Vessels and Piping ; Volume 86, Issue 2-3 , 2009 , Pages 143-152 ; 03080161 (ISSN) ; Kargarnovin, M. H ; Naghdabadi, R ; Sharif University of Technology
2009
Abstract
Governing equilibrium equations of thick-walled spherical vessels made of material following linear strain hardening and subjected to a steady-state radial temperature gradient using elasto-plastic analysis are derived. By considering a maximum plastic radius and using the concept of thermal autofrettage for the strengthening mechanism, the optimum wall thickness of the vessel for a given temperature gradient across the wall thickness is obtained. Finally, in the case of thermal loading on a vessel, the effect of convective heat transfer on the optimum thickness is studied and a general formula for the optimum wall thickness and design graphs for several different cases are presented. © 2008...
Elasto-Plastic Design of Thick-Walled FG Vessels under Pressure or Temperature Gradient Loadings
, M.Sc. Thesis Sharif University of Technology ; Kargarnovin, Mohammad Hossein (Supervisor)
Abstract
Nowadays functionally graded materials have many applications in various industries. One of these applications can be the manufacturing of thick-walled vessels. Thick-walled vessels under internal pressure and high temperatures gradient require materials with higher strength, like Functionally Graded Materials (FGM) and can be reinforced by some mechanical processes like autofrettage. In this process under certain loading some part of vessels enters into plastic zone and upon unloading some residual stresses will be generated. Moreover it is very important to find out the depth of this plastic zone, In addition, minimizing the stress distribution vs. depth of plastic zone under applied...
Constitutive law of finite deformation elastoplasticity with proportional loadings
, Article Journal of Pressure Vessel Technology, Transactions of the ASME ; Volume 135, Issue 6 , September , 2013 ; 00949930 (ISSN) ; Naghdabadi, R ; Sharif University of Technology
2013
Abstract
In this paper, decomposition of the total strain into elastic and plastic parts is investigated for extension of elastic-type constitutive models to finite deformation elastoplasticity. In order to model the elastic behavior, a Hookean-type constitutive equation based on the logarithmic strain is considered. Based on this constitutive equation and assuming the deformation theory of Hencky as well as the yield criteria of von Mises, the elastic-plastic behavior of materials at finite deformation is modeled in the case of the proportional loading. Moreover, this elastoplastic model is applied in order to determine the stress distribution in thick-walled cylindrical pressure vessels at finite...