The Application of Hasofer-Lind Method in Reliability Design of Thin-Walled Cylindrical Shell

2012 ◽  
Vol 249-250 ◽  
pp. 303-306
Author(s):  
Yu Long Zheng ◽  
Zhi Min Lu ◽  
Lin Lin Wang ◽  
Lin Zhang ◽  
Guang Liang Zhou
Keyword(s):  
Cylindrical Shell ◽  
Internal Pressure ◽  
Wall Thickness ◽  
Design Method ◽  
Performance Function ◽  
Reliability Design ◽  
Second Moment ◽  
The Difference ◽  
Second Moment Method ◽  
The Second Moment Method

Hasofer-Lind method was applied to reliability design of cylindrical shell with internal pressure. The respective reliability design thickness of different diameter ratio was obtained in the case and compared with the thickness by the second moment reliability design method. The results showed that the wall thickness of cylindrical shell with internal pressure is the thinnest by using Hasofer-Lind method. And it is closest to the wall thickness of the second moment method in which the performance function was defined as the difference in actual wall thickness and the wall thickness needed for cylindrical shell with internal pressure.

Influence of the Wall Thickness on the Allowable and Failure Pressures of Two- and Tree-Way Globe Valve Bodies

2011 ◽  
Vol 488-489 ◽  
pp. 646-649
Author(s):  
Milan Opalić ◽  
Ivica Galić ◽  
Krešimir Vučković
Keyword(s):  
Internal Pressure ◽  
Wall Thickness ◽  
Design Method ◽  
Equivalent Plastic Strain ◽  
Strain Curve ◽  
Linear Motion ◽  
Valve Body ◽  
Failure Pressure ◽  
Critical Location ◽  
Globe Valve

A globe valve is a linear motion valve used to shut off and regulate fluid flow in pipelines. Depending on the number of process connections, they are produced as two‑ or three-way valves. The main valve component carrying the internal pressure is the valve body. For safe exploitation, the valves are designed with the allowable internal pressure taken into consideration. The aim of this paper is to investigate the influence of the wall thickness on the allowable and failure pressures of two- and tree-way globe valve bodies, DN50 and DN100 respectively. Twice-elastic-slope (TES) and the tangent‑intersection (TI) methods are used to obtain the plastic collapse pressures at the critical location which was determined (Fig. 1a and 1b) at the location where maximum equivalent plastic strain throughout the valve body thickness reaches the outer surface. Obtained values are used afterwards to calculate corresponding allowable pressures according to the limit design method, while the failure pressure at the same location was determined as the highest point from the load-maximal principal strain curve. Calculated allowable pressure values, for both valve bodies, are compared with the corresponding ones obtained using the EN standard.

Study on Minimum Wall Thickness Requirement of Reactor Vessel of Fast Reactor for Seismic Buckling by System Based Code

2013 ◽  
Author(s):  
Shigeru Takaya ◽  
Daigo Watanabe ◽  
Shinobu Yokoi ◽  
Yoshio Kamishima ◽  
Kenichi Kurisaka ◽  
...  
Keyword(s):  
Wall Thickness ◽  
Fast Reactor ◽  
Design Method ◽  
Random Variable ◽  
Mean Value ◽  
Reactor Vessel ◽  
Seismic Load ◽  
Reliability Design ◽  
Plant Safety ◽  
Distribution Type

In this paper, minimum wall thickness requirement of reactor vessel of fast reactor for seismic buckling is discussed on the basis of the System Based Code (SBC) concept. One of key concepts of SBC is the margin optimization. To implement this concept, reliability design method is employed, and the target reliability for seismic buckling of reactor vessel is derived from nuclear plant safety goals. Input data for reliability evaluation such as distribution type, mean value and standard deviation of random variable are prepared. Seismic hazard is considered to evaluate uncertainty of seismic load. Wall thickness needed to achieve the target reliability is evaluated, and as a result, it is shown that the minimum wall thickness can be reduced from that required by a deterministic design method.

FEM Stress Analysis and the Sealing Performance Evaluation of Pipe Flange Connections Subjected to External Bending Moments and Internal Pressure

2011 ◽  
Author(s):  
Kazuhide Horiuchi ◽  
Yoshio Takagi ◽  
Toshiyuki Sawa
Keyword(s):  
Tensile Strength ◽  
Internal Pressure ◽  
Design Method ◽  
Bending Moment ◽  
Initial Contact ◽  
Bending Moments ◽  
Loading History ◽  
Pipe Length ◽  
Sealing Performance ◽  
The Difference

In previous study, the characteristics of the pipe flange connections such as the contact gasket stress distribution and the sealing performance of the connection subjected to bending moments are examined. The result suggests that the leakage increases as the bending moment increases. However, a design method for the connection subjected to bending moment is not taken into consideration. The sealing performance of the connection for the different loading history is changed due to non-linearity and hysteresis of non-asbestos gasket. After the pipe flange connections are tightened, bending moment prior to internal pressure is applied due to misalignment of the connections with bolts and nuts. So, it is necessary to examine the difference in the sealing performance due to different loading history and to establish a design method for the connections subjected to bending moment and internal pressure. In this study, the difference in the sealing performance due to different loading history is examined and pipe length in each usage condition is determined for the two loading histories using tensile strength of hub side and allowable leak rate of soppy bubble method to establish a design method of flange subjected to bending moment. The result suggests the average contact gasket stress for the different loading history is changed due to non-linearity and hysteresis of non-asbestos gasket and pipe length in each initial contact gasket stress is determined for the two loading histories.

Photochemical Studies. XVI. Second Moment Analysis of the Electron Spin Resonance Spectra of Radicals Formed by Ultraviolet Irradiation of 9-Phenylacridine and of Acridine

1973 ◽  
Vol 51 (21) ◽  
pp. 3508-3513 ◽  
Author(s):  
Azélio Castellano ◽  
Jean-Pierre Catteau ◽  
Alain Lablache-Combier ◽  
Guy Allan
Keyword(s):  
Electron Spin Resonance ◽  
Moment Method ◽  
Membered Ring ◽  
Second Moment ◽  
Second Moments ◽  
Deuterated Analog ◽  
Spin Resonance ◽  
Second Moment Method ◽  
The Second Moment Method ◽  
Spin Densities

The irradiation of 9-phenylacridine in methanol, ethanol, or ether leads to the formation of the 9-phenylacridinyl radical. In methanol-d4, the radical formed is the singly deuterated analog. The structure of these radicals, which exhibit a hyperfine structure in their e.s.r. spectra measured at 233 °K, is supported by simulation of the spectra using calculated spin densities. The agreement between the experimental and theoretical second moment values of the deuterated radical indicates that the parameters previously chosen for the calculation of the theoretical second moments of pyridinyl-type radicals derived from six-membered ring azaaromatics are suitable and that the second moment method can be used in studies of radicals of this type. We conclude that acridine irradiated in methanol-d4 leads to the formation of the singly deuterated acridinyl radical.

Effect of Orthotropic Mechanical Property on the Limit Load of Cylindrical Shell under Internal Pressure

2019 ◽  
Vol 795 ◽  
pp. 401-408 ◽  
Author(s):  
Cheng Miao ◽  
Fei Lv ◽  
Chang Yu Zhou ◽  
Xiao Hua He
Keyword(s):  
Mechanical Property ◽  
Cylindrical Shell ◽  
Yield Strength ◽  
Internal Pressure ◽  
Cylindrical Shells ◽  
Limit Load ◽  
Circumferential Direction ◽  
Limit Loads ◽  
Isotropic Cylindrical Shell ◽  
The Difference

At present the orthotropic pressurized metal structure is generally used as the isotropic one, ignoring the anisotropic characteristics of material caused during rolling process. At the same time, the elastic stress analysis design method is commonly used in pressure vessel, and the load capacity coming from plasticity of material has not been utilized. Therefore, elastic-plastic analysis of orthotropic pressurized structure is of great theoretical significance and engineering value. In present paper the limit load of orthotropic titanium cylindrical shell under internal pressure was studied. By finite element method with twice elastic slope criterion the variations of limit load for orthotropic and isotropic titanium cylindrical shells under different diameter-thickness ratios were investigated. The effect of orthotropic mechanical property on limit load of titanium cylindrical shell was discussed. At the same time, the difference of limit loads between orthotropic and isotropic titanium cylindrical shells was compared. The calculation results show that the limit loads of orthotropic and isotropic titanium cylindrical shell increase with the diameter-thickness ratio, and the limit load of orthotropic titanium cylindrical shell increases more obviously. Additionally, if the yield strength of isotropic cylindrical shell is the same as or close to the yield strength of circumferential direction for orthotropic titanium cylindrical shell, the difference of limit load is smaller. While the yield strength of isotropic cylindrical shell is much different from the yield strength of circumferential direction for orthotropic titanium cylindrical shell, the difference of the limit load is higher.

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