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pressure-vessels
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Verification of stress model in dissimilar materials of varying cladded pipes using a similar cladded plate model
, Article ASME 2020 Pressure Vessels and Piping Conference, PVP 2020, 3 August 2020 ; Volume 8 , October , 2020 ; Wang, B ; Chizari, M ; Wrobel, L ; Pressure Vessels and Piping Division ; Sharif University of Technology
American Society of Mechanical Engineers (ASME)
2020
Abstract
This paper continues previous research performed by the authors on the modelling of dissimilar welded joints with varying clad thicknesses. This study aims to validate the use of a clad plate model as a replacement to the previous clad pipe model. To fulfill the hypothesis of the study, possible deformation or angular shrinkages occurring at weld joints have been simulated using a commercial finite element software. In parallel, angular shrinkages have been validated using the experimental data with the underlying concept of Gaussian transformation of plates into pipes. The welding of the two dissimilar materials has been carried out in-house with the aid of a Tungsten Arc weld with dynamic...
Nonlinear plastic modeling of materials based on the generalized strain rate tensor
, Article ASME 2008 Pressure Vessels and Piping Conference, PVP2008, Chicago, IL, 27 July 2008 through 31 July 2008 ; Volume 3 , July , 2008 , Pages 499-505 ; 0277027X (ISSN); 9780791848265 (ISBN) ; Naghdabadi, R ; Pressure Vessels and Piping ; Sharif University of Technology
2008
Abstract
In this paper, a method for modeling of elastic-plastic hardening materials under large deformations is proposed. In this model the generalized strain rate tensor is used. Such a tensor is obtained on the basis of the method which was introduced by the authors. Based on the generalized strain rate tensor, a flow rule, a Prager-type kinematic hardening equation and a kinematic decomposition is proposed and the governing equations for such materials are obtained. As an application, the governing equations for the simple shear problem are solved and some results are compared with those in the literature. Copyright © 2008 by ASME
Boundary identification between LBLOCA and SBLOCA based on stratification and temperature gradient in two-phase PTS
, Article Annals of Nuclear Energy ; Volume 115 , May , 2018 , Pages 430-441 ; 03064549 (ISSN) ; Ghofrani, M. B ; D'Auria, F ; Sharif University of Technology
Elsevier Ltd
2018
Abstract
Temperature gradient on the thick Reactor Pressure Vessel (RPV), caused by sudden overcooling events, especially in the downcomer, would intensify the propagation of structural defects. This situation known as Pressurized Thermal Shock (PTS) could be created in case of Emergency Core Cooling System (ECCS) actuation which leads to injection of cold water into the cold leg of the primary loop in some accidents, e.g. Loss Of Coolant Accident (LOCA). Prediction of Plant response to LOCA and water temperature gradient in the downcomer are performed in thermal-hydraulic section of PTS analysis. Employment of system codes is one of the proposed procedures in literature to obtain plant response and...
Development of New Material Selection Method by Using QFD Matrix
, M.Sc. Thesis Sharif University of Technology ; Abedian, Ali (Supervisor)
Abstract
Today, the material selection process plays an important role in all engineering design branches. Generally, in transition from concept design to detail design, designers and engineers need to find specific materials to optimize performance of the systems. There are introduced nearly 80000 engineering materials up to now, i.e. metallic alloys, composite materials, plastics, ceramics, glass and etc. These large amounts of materials and the wide range of manufacturing processes causes engineers always seek new material selection methods. In material selection it’s require to consider advantages, restrictions, necessities of method and this phenomenon appear because of design problem that...
Thermal-Hydraulic Simulation and Analysis of Two-Phase Thermal Shock in Pressurized Light Water Power Plants
, Ph.D. Dissertation Sharif University of Technology ; Ghofrani, Mohammad Bagher (Supervisor)
Abstract
As a result of fission reaction in a nuclear reactor, the produced high neutron flux would affect the material of Reactor Pressure Vessel (RPV). This neutron radiation has a detrimental impact on the mechanical properties of the RPV material such as hardening (or embrittlement) while neutrons are absorbed by the material. A major concern in embrittled RPVs is propagation of critical flaw causing through-wall cracks. Some transients leading to overcooling of RPV intensify the propagation of theses cracks and result in thermal load on RPV, known as Pressurized Thermal Shock (PTS). Such situation could be created in case of Emergency Core Cooling System (ECCS) actuation which leads to injection...
Short Term and Long Term Analysis of Radiation Damage in Carbon Based Steels with Emphasis on Reactor Pressure Vessel
, Ph.D. Dissertation Sharif University of Technology ; Samadfam, Mohammad (Supervisor) ; Feghhi, Amir Hossein (Supervisor)
Abstract
Steels as structural materials of pressure vessels of nuclear reactors, in addition to high temperatures and pressures, are exposed to ionizing radiation such as neutrons. The primary effects of damage caused by exposing these solids to radiation are the displacement of atoms from their equilibrium positions and the formation of point defects and damage clusters caused by damage accumulation due to displacement cascades produced by transmitting the energy of the incident particle to an atom by interactions such as elastic and inelastic scatterings neutrons with the nucleus. These microstructural changes cause large structural defects such as swelling, cracking, cracking, creep, reducing...
Multi criteria site selection model for wind-compressed air energy storage power plants in Iran
, Article Renewable and Sustainable Energy Reviews ; Vol. 32 , April , 2014 , pp. 579-590 ; ISSN: 13640321 ; Noorollahi, Y ; Abbaspour, M ; Yousefi, H ; Sharif University of Technology
Abstract
In this research, a site selection method for wind-compressed air energy storage (wind-CAES) power plants was developed and Iran was selected as a case study for modeling. The parameters delineated criteria for potential wind development localities for wind-CAES power plant sites. One important consequence of this research was the identification of the wind energy potential for wind-CAES sites. The theoretical wind energy potential of Iran of greater than 50 W/m2 was identified from a wind atlas of Iran. The model produced factor maps by considering the boundary conditions of the input data and created geo-databases from the outputs maps. The main factor maps were electrical grids and...
Experimental investigation of characteristic curve for gas-lift pump
, Article Journal of Petroleum Science and Engineering ; Volume 62, Issue 1 , 2014 , Pages 156-170 ; ISSN: 09204105 ; Raffiee, A. H ; Saidi, M. H ; Sharif University of Technology
Abstract
Using gas-liquid lifting pumps is a quite different technology for pumping two or three phase flows rather than other types of pumping systems. Therefore, finding performance characteristic chart for this type of pumping system seems to be necessary. In this type of pumping system, the liquid phase is pushed upward by the compressed air which has been injected in the bottom of upriser pipe of the pump. Therefore, compressed air acts as the driving force in gas lifting pumps instead of moving parts in ordinary pumps. It can be concluded that the definition of characteristic curve used for ordinary pump is not very appropriate for this type of pumping system. In this study, it has been...
Residual stresses in autofrettaged vessel made of functionally graded material
, Article Engineering Structures ; Volume 31, Issue 12 , 2009 , Pages 2930-2935 ; 01410296 (ISSN) ; Farrahi, G. H ; Maleki, M ; Nayeb Hashemi, H ; Vaziri, A ; Sharif University of Technology
Abstract
We used an extension of the Variable Material Property method for materials with varying elastic and plastic properties to evaluate the residual stresses in an autofrettaged thick vessel made of functionally graded metal-ceramic composite. It is shown that the reinforcement of the metal vessel by ceramic particles, with an increasing ceramic volume fraction from inner to outer radius, increases the magnitude of compressive residual stresses at the inner section of an autofrettaged vessel and thus, could lead to better fatigue life and load-carrying capacity of the vessel. A parametric study is carried out to highlight the role of ceramic particle strength and spatial distribution, as well as...
Experimental and numerical study of geometrically nonlinear behavior of corrugated laminated composite shells using a nonlinear layer-wise shell FE formulation
, Article Engineering Structures ; Volume 184 , 2019 , Pages 61-73 ; 01410296 (ISSN) ; Hosseini Kordkheili, S. A ; Kress, G ; Sharif University of Technology
Elsevier Ltd
2019
Abstract
This paper presents experimental and numerical studies on the geometrically nonlinear behavior of corrugated laminated composite shells (CLCS) under quasi-static loading along the corrugated direction. A geometrically nonlinear layer-wise shell finite element formulation is adopted to study the behavior of CLCS under large deformation by modeling of incremental different moduli in the tensile and compressive regimes through the thickness, where the spatial location of neutral axis shifts with deformation. A master curve is presented to estimate the value of compressive modulus from given tensile and flexural moduli. Using the prepreg autoclave method, the paper also describes practical...
A linearized transmission expansion planning model under N − 1 criterion for enhancing grid-scale system flexibility via compressed air energy storage integration
, Article IET Generation, Transmission and Distribution ; 2021 ; 17518687 (ISSN) ; Moeini Aghtaie, M ; Fotuhi Firuzabad, M ; Dehghanian, P ; Khoshjahan, M ; Sharif University of Technology
John Wiley and Sons Inc
2021
Abstract
The concept of flexibility is defined as the power systems’ ability to effectively respond to changes in power generation and demand profiles to maintain the supply–demand balance. However, the inherent flexibility margins required for successful operation have been recently challenged by the unprecedented arrival of uncertainties, driven by constantly changing demand, failure of conventional units, and the intermittent outputs of renewable energy sources (RES). Tackling these challenges, energy storage systems (ESS) as one important player of the new power grids can enhance the system flexibility. It, therefore, calls for an efficient planning procedure to ensure flexibility margins by...
A linearized transmission expansion planning model under N − 1 criterion for enhancing grid-scale system flexibility via compressed air energy storage integration
, Article IET Generation, Transmission and Distribution ; Volume 16, Issue 2 , 2022 , Pages 208-218 ; 17518687 (ISSN) ; Moeini Aghtaie, M ; Fotuhi Firuzabad, M ; Dehghanian, P ; Khoshjahan, M ; Sharif University of Technology
John Wiley and Sons Inc
2022
Abstract
The concept of flexibility is defined as the power systems’ ability to effectively respond to changes in power generation and demand profiles to maintain the supply–demand balance. However, the inherent flexibility margins required for successful operation have been recently challenged by the unprecedented arrival of uncertainties, driven by constantly changing demand, failure of conventional units, and the intermittent outputs of renewable energy sources (RES). Tackling these challenges, energy storage systems (ESS) as one important player of the new power grids can enhance the system flexibility. It, therefore, calls for an efficient planning procedure to ensure flexibility margins by...
An analytical framework for the solution of autofrettaged tubes under constant axial strain condition
, Article Journal of Pressure Vessel Technology, Transactions of the ASME ; Volume 131, Issue 6 , 2009 ; 00949930 (ISSN) ; Farrahi, G. H ; Movahhedy, M. R ; Sharif University of Technology
Abstract
Autofrettage is a technique for introducing beneficial residual stresses into cylinders. Both analytical and numerical methods are used for the analysis of the autofrettage process. Analytical methods have been presented only for special cases of autofrettage. In this work, an analytical framework for the solution of autofrettaged tubes with constant axial strain conditions is developed. Material behavior is assumed to be incompressible, and two different quadratic polynomials are used for strain hardening in loading and unloading. Clearly, elastic perfectly plastic and linear hardening materials are the special cases of this general model. This quadratic material model is convenient for the...
New turbulence modeling for simulation of Direct Contact Condensation in two-phase pressurized thermal shock
, Article Progress in Nuclear Energy ; Volume 108 , 2018 , Pages 358-371 ; 01491970 (ISSN) ; Ghofrani, M. B ; D'Auria, F ; Sharif University of Technology
Elsevier Ltd
2018
Abstract
Injection of Emergency Core Cooling System (ECCS) water into the primary loops of the Pressurized Water Reactors (PWRs) leads to rapid cooling of Reactor Pressure Vessel (RPV) inside wall after Loss Of Coolant Accident (LOCA). This condition, known as Pressurized Thermal Shock (PTS) intensifies the propagation of the RPV structural defects and would be considered as an ageing mechanism. For structural and fracture analysis of RPV wall, thermal-hydraulic analysis of PTS should be accomplished to obtain the steam/water flow characteristics in the downcomer. For this purpose, simulation of steam/water stratified flow (due to density difference) after the injection point should be done by...
Experimental study of the relationship between fracture initiation toughness and brittle crack arrest toughness predicted from small-scale testing
, Article Theoretical and Applied Fracture Mechanics ; Volume 110 , 2020 ; Mehmanparast, A ; Kulka, R ; Moore, P ; Xu, L ; Farrahi, G. H ; Sharif University of Technology
Elsevier B.V
2020
Abstract
It is vital to prevent brittle cracks in large structures. This is particularly important for a number of industry sectors including offshore wind, Oil & Gas, and shipbuilding where structural failure risks loss of human life and loss of expensive assets. Some modern steels exhibit high Charpy energy – i.e. high initiation fracture toughness, but poor resistance to crack propagation – i.e. low crack arrest toughness. The correlation between initiation and arrest toughness measured through small-scale testing is investigated in five different steels, which include S355 structural steel (with two different thicknesses), X65 pipeline steel, two high strength reactor pressure vessel steels and...