Analysis and Comparison of Pad Reinforcement of Pressure Vessel by Elastic and Elastoplastic FEM

2007 ◽  
Author(s):  
Lihua Liang ◽  
Zengliang Gao ◽  
Yangjian Xu ◽  
Kangda Zhang ◽  
Zhaohui Fan
Keyword(s):  
Cylindrical Shell ◽  
Stress Distribution ◽  
Stress Analysis ◽  
Maximum Stress ◽  
Constitutive Relations ◽  
Contact Model ◽  
Integral Model ◽  
The Difference ◽  
Shell Intersections ◽  
Different Diameters

Considering reinforcement pad and the cylindrical shell as an integral model and a contact model, stress analysis for opening-reinforcement structures of a cylindrical shell is performed by elastic and elastoplastic FEM. By comparison of two sub-models and two material constitutive relations (elastic and elastoplastic), the stress distribution of cylindrical shell intersections by the contact model is similar to that by the integral model, but there are some differences of the stress at contact surfaces of the shell and the reinforcement pad between by the contact model and by the integral model. In general, the stress analysis of the integral model for pad reinforcement can approximately represent that of the contact model. Finite element analyses for different nozzle diameters and different oblique angles in nozzle and cylinder shell intersections are carried out. The stress distribution and the maximum stress are affected by oblique angle. But the difference of the maximum stress intensity among different diameters is small.

scholarly journals Stress Analysis of HCPB BB under Ex-Vessel LOCA Condition

2021 ◽  
Vol 2108 (1) ◽  
pp. 012088
Author(s):  
Mengdi Dai ◽  
Xiaomo Wang
Keyword(s):  
Stress Distribution ◽  
Stress Field ◽  
Stress Analysis ◽  
Cross Section ◽  
Maximum Stress ◽  
Fusion Reactor ◽  
Vacuum Vessel ◽  
Loss Of Coolant Accident ◽  
Loss Of Coolant ◽  
Size Dimension

Abstract Helium Cooled Pebble Bed Breeding Blanket (HCPB BB) is a kind of concept for the European demonstration fusion reactor (DEMO). The blanket attachment system plays an important role in the mechanical connection of the BB and vacuum vessel. Typically, the mechanical and thermal loads should meet the requirement to avoid collapse of the system with off-normal conditions, e.g., under ex-vessel Loss of Coolant Accident (LOCA. This paper investigates the loading requirement corresponding to the maximum stress that can sustain to avoid the LOCA condition. Firstly, a model of the BB is constructed using SolidWorks. Then, stress analysis is carried out based on the cross section of the blanket. Through simulation, the critical condition for the LOCA case and the maximum stress value for the model are obtained. According to the relevant size dimension from the reference, the blanket’s cross section is drawn, and one can get the stress field under the ex-vessel LOCA through stress analysis. The stress distribution under the ex-vessel LOCA condition is simulated to find out the maximum stress field that the blanket can sustain through this paper. The significance is to predict the possible conditions leading to an accident and find possible methods to avoid them.

Modulation instability in nonlinear chiral fiber

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Demissie Jobir Gelmecha ◽  
Ram Sewak Singh
Keyword(s):  
Theoretical Model ◽  
Numerical Simulations ◽  
Pulse Propagation ◽  
Modulation Instability ◽  
Constitutive Relations ◽  
Gain Spectrum ◽  
Circularly Polarized ◽  
Left Handed ◽  
Simulation Results ◽  
The Difference

AbstractIn this paper, the rigorous derivations of generalized coupled chiral nonlinear Schrödinger equations (CCNLSEs) and their modulation instability analysis have been explored theoretically and computationally. With the consideration of Maxwell’s equations and Post’s constitutive relations, a generalized CCNLSE has been derived, which describes the evolution of left-handed circularly polarized (LCP) and right-handed circularly polarized (RCP) components propagating through single-core nonlinear chiral fiber. The analysis of modulation instability in nonlinear chiral fiber has been investigated starting from CCNLSEs. Based on a theoretical model and numerical simulations, the difference on the modulation instability gain spectrum in LCP and RCP components through chiral fiber has been analyzed by considering loss and chirality into account. The obtained simulation results have shown that the loss distorts the sidebands of the modulation instability gain spectrum, while chirality modulates the gain for LCP and RCP components in a different manner. This suggests that adjusting chirality strength may control the loss, and nonlinearity simultaneously provides stable modulated pulse propagation.

Research of the Connecting Form about the Spherical Shell and the Nozzle

2011 ◽  
Vol 413 ◽  
pp. 520-523
Author(s):  
Cai Xia Luo
Keyword(s):  
Finite Element ◽  
Stress Distribution ◽  
Finite Element Model ◽  
Spherical Shell ◽  
Maximum Stress ◽  
Peak Stress ◽  
Element Model ◽  
Small Opening ◽  
Large Opening ◽  
Reducing Stress

The Stress Distribution in the Connection of the Spherical Shell and the Opening Nozzle Is Very Complex. Sharp-Angled Transition and Round Transition Are Used Respectively in the Connection in the Light of the Spherical Shell with the Small Opening and the Large One. the Influence of the Two Connecting Forms on Stress Distribution Is Analyzed by Establishing Finite Element Model and Solving it. the Result Shows there Is Obvious Stress Concentration in the Connection. Round Transition Can Reduce the Maximum Stress in Comparison with Sharp-Angled Transition in both Cases of the Small Opening and the Large Opening, Mainly Reducing the Bending Stress and the Peak Stress, but Not the Membrane Stress. the Effect of Round Transition on Reducing Stress Was Not Significant. so Sharp-Angled Transition Should Be Adopted in the Connection when a Finite Element Model Is Built for Simplification in the Future.

Stress Distribution Analysis of Different Types of Blade for a Fermentation System

2013 ◽  
Vol 479-480 ◽  
pp. 319-323
Author(s):  
Cheng Chi Wang ◽  
Po Jen Cheng ◽  
Kuo Chi Liu
Keyword(s):  
Stress Distribution ◽  
Maximum Stress ◽  
Effective Means ◽  
Materials Processing ◽  
Distribution Analysis ◽  
Stress Distributions ◽  
Fermentation System ◽  
Different Types ◽  
Inclined Angle ◽  
Key Parameter

Fermentation system is widely used for food manufacturing, materials processing and chemical reaction etc. Different types of blade in the tank for fermentation cause distinct stress distributions on the surface between fluid and blade, and appear various flow fields in the tank. So, this paper is mainly focused on analyzing the stress field of blades under different scales of blade with fixing rotational speed. The results show that the ratio of blade length to width influences stress distribution on the blades. At the same time, the inclined angle of blade is also the key parameter for the consideration of design and appropriate design will decrease the maximum stress. The results provide an effective means of gaining insights into the stress distribution of fermentation system.

Abstract 15322: Trifecta vs. Mitroflow: Superior Hemodynamics Despite Similar Design

Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
Mahmoud Diab ◽  
Gloria Faerber ◽  
Ivliane Tsanava ◽  
Martin Breuer ◽  
Mario Walther ◽  
...  
Keyword(s):  
Aortic Annulus ◽  
Special Consideration ◽  
Pressure Gradients ◽  
Valve Design ◽  
Innovative Design ◽  
Mean Pressure ◽  
The Difference ◽  
Different Diameters

Purpose: Hemodynamic results of stented tissue valves are influenced by both valve design and sizing strategy. The Mitroflow and the Trifecta have an innovative design where the pericardium is wrapped around the stent. The goal of this study was to compare both valves giving special consideration to the suggested sizing strategies. Methods: We obtained pressure gradients from discharge echocardiograms from all patients having received an isolated Trifecta (n=104) or Mitroflow (n=246) between 01/2007 and 01/2014. We compared the results by size label and by the most likely selected size according to the suggested sizing strategy. This is important because the prostheses, despite having a similar design, have different diameters for the same size label and different sizing strategies. Results: The majority of implanted valves were size labels 21 and 23 (82.7% of the Trifecta and 74.8% of the Mitroflow). Mean pressure radients were lowest with Trifecta (Trifecta vs. Mitroflow, label-21: 11.4±4.65 vs 13.6±5.23 mmHg, label-23: 9.23±3.38 vs. 11.8±4.42 mmHg, p< 0.05, and label-25: 11.2±4.97 vs 12.0±4.46 mmHg, n.s.). The sizers for the Trifecta are metric, while those for the Mitroflow are 2-3 mm larger than the corresponding size label. It is therefore likely that for a patient with a 23 mm aortic annulus, a 23 Trifecta but often only a 21 Mitroflow is selected. Thus, comparing the Trifecta to the Mitroflow not by size label but by selected valve (e.g., 23 vs. 21) would therefore only increase the difference. Conclusion: The Trifecta shows a hemodynamic advantage over the Mitroflow which is not likely associated with the applied sizing strategy.

Stress Calculation of a Spherical Tank on Settled Ground Based on FEM

2013 ◽  
Vol 331 ◽  
pp. 110-113
Author(s):  
Hong Li Gao ◽  
Wei Jun Li ◽  
Zhi Hai Li
Keyword(s):  
Stress Distribution ◽  
Maximum Stress ◽  
Differential Settlement ◽  
Foundation Settlement ◽  
Stress Calculation ◽  
Spherical Tank

In this paper, a model of a LGP spherical tank supported by 8 equator tangent-type supporting on settled ground was built.The stress on the shell,on the pillars and on the connection of pillars with shell were calculated,the stress distribution on shell,pillars and the connection of pillars with shell were obtained, the influence of foundation settlement to the stress of shell and pillars were studied. The results showed that the differential settlement produced a less affect on the shell,but a greater impact on the pillars. The maximum stress arose at the connection between pillars and shell ,there is a big stress area in the connectors area.

Finite Element Stress Analysis of Intersection Region of Nozzle and Blind Flange

2012 ◽  
Vol 605-607 ◽  
pp. 1307-1310
Author(s):  
Jun Hua Dong ◽  
Bing Jun Gao
Keyword(s):  
Finite Element ◽  
Stress Intensity ◽  
Stress Analysis ◽  
Maximum Stress ◽  
Stress Variation ◽  
Finite Element Stress Analysis ◽  
Maximum Stress Intensity ◽  
Variation Rule ◽  
Finite Element Stress

The stress analysis of the intersections region of nozzle & blind flange is implemented by means of FEA. The stress variation rule was obtained and the maximum Stress intensity is at the inside of intersections region of nozzle & blind flange. In accordance with JB4732-1995 (2005 Confirmed edition), the safety of structure was evaluated. The results show that the dimensiom given in the paper can meet the requirement for safety.

Analysis of Stress Distribution for Powder Compression Molding by Finite Element Method

2019 ◽  
Vol 891 ◽  
pp. 269-274 ◽  
Author(s):  
Prakorb Chartpuk ◽  
Chaiwat Chaimahapuk
Keyword(s):  
Stress Distribution ◽  
Natural Frequency ◽  
Ceramic Powder ◽  
Bearing Steel ◽  
Outer Diameter ◽  
Maximum Compression ◽  
Aisi 52100 ◽  
Steel Aisi ◽  
The Difference ◽  
Powder Compression

The ultrasonic mold was designed for the ceramic powder compression. CAD and CAE were used in the design to analyze the mold strength and its natural frequency. The study of stress distribution and compression in upper and lower punch, mold body and waveguide comparison of stresses was analyzed by FEA experiments under maximum compression at 50,000 N to validate the results of both methods and the mold natural frequency. The difference between FEA and experimental analysis was 3-7%, acceptable. The redesign results in a cylindrical mold body with the outer diameter of 80 mm, the height of 100 mm, and the upper punch of 125 mm in length. The six sides are 26 mm of the high waveguide with 100 mm height. The internal and external diameters are 80 and 110 mm, respectively. The mold has been redesigned and can support the maximum compression force of 1,500 kN. with the bearing steel, AISI 52100, obtainable hardness 65 HRC, the stress concentration occurs at the neck of the upper punch using the ultrasonic at 12.00 to 12.45 kHz.

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