Probability Analysis of Critical Load of Sphere-Cylinder Combined Shell Structures

2016 ◽  
Author(s):  
Weijun Xu ◽  
Yan Feng ◽  
Xiaotian Wang
Keyword(s):  
Cylindrical Shell ◽  
Critical Load ◽  
Shell Structure ◽  
Failure Modes ◽  
Simulation Method ◽  
Probability Analysis ◽  
Shell Structures ◽  
Probability Models ◽  
Stiffened Cylindrical Shell ◽  
Spherical Structures

The critical load of submersible structures is normally analyzed in deterministic method. However, some factors including structural sizes, material properties and the location of the components, etc., have random characteristics due to smelting and construction process. In other words, the critical load of submersible structures has uncertainty, so these parameters should be considered as random variables. In terms of sphere-cylinder combined shell structures, the critical loads on the cylindrical shell and spherical structures should be considered together to avoid the influence of boundary conditions on the analysis results. This paper focuses on the probability analysis of sphere-cylinder combined shell structures under critical load. According to the GJB calculation method of submarine design, the security calibration ranges of ring-stiffened cylindrical shell and spherical shell are determined, and seven kinds of failure modes of sphere-cylinder combined shell structure are supposed. The corresponding probability models of sphere-cylinder combined shell structure have been established, and the reliability calculations of each failure mode are conducted in FOSM method, JC method and Monte Carlo simulation method. Considering the correlation between different failure modes, reliability series model of sphere-cylinder combined shell structure is applied in the probability analysis. It is verified by comparison of ring-stiffened cylindrical shell and sphere-cylinder combined shell, with the increase of the structure components, the reliability of structure system shows a decline tendency.

Investigation on the Structure Strength and Stability of Ring Stiffened Cylindrical Shell With Long Compartment and Large Stiffener

2017 ◽  
Author(s):  
Yan Feng ◽  
Hui Li ◽  
Chenfeng Li ◽  
Junjie Ruan ◽  
Qiyou Zhang ◽  
...  
Keyword(s):  
Cylindrical Shell ◽  
Shell Structure ◽  
Failure Modes ◽  
High Strength Steels ◽  
High Strength ◽  
Theoretical Method ◽  
Utilization Efficiency ◽  
Stiffened Cylindrical Shell ◽  
Vessel Structure ◽  
Current Design

With the increasing status of the sea, the research and manufacture of submersible vessel will be paid more attention. In order to enlarge the submergence depth and utilization efficiency of submersible vessel space, long compartment structures of high strength steels and in various forms are widely adopted. The strength problem of such structure is easy to be guaranteed, while the resulting stability problem is becoming more and more serious. For a ring-stiffened cylindrical shell structure with long compartment, one or two large stiffeners are used on the shell structure to ensure its overall stability. This paper studies the strength and stability of the long compartment cylindrical shell structure, with a special emphasis on the stability problems of overall long compartment structures and large stiffeners. The failure modes and critical load under deep water are analyzed by a theoretical method and also a finite element method. The formula for calculating the large stiffener of submersible vessel structure is derived based on the theory of elastic mechanics, and the defect and deficiency of the formula used in the current design specification is pointed out. The influence of large stiffener position and structure form on the critical pressure of submersible cylindrical shell structure is studied. The results of theoretical analysis and numerical simulation are also compared and discussed.

A Study on the Free Vibration of the Prestressed Joined Cylindricalspherical Shell Structures

2013 ◽  
Vol 390 ◽  
pp. 207-214 ◽  
Author(s):  
Mahdi Yusefzad ◽  
Firouz Bakhtiari Nejad
Keyword(s):  
Cylindrical Shell ◽  
Free Vibration ◽  
Shell Structure ◽  
Shell Theory ◽  
Natural Frequencies ◽  
Vibration Characteristics ◽  
Shell Structures ◽  
Mode Shapes ◽  
Free Boundary Conditions ◽  
Modal Test

The free vibration characteristics of the prestressed joined spherical–cylindrical shell with free-free boundary conditions are investigated. The Flügge shell theory and Rayleigh-Ritz energy method are applied in order to analyze the free vibration characteristics of the joined shell. In the modal test, the LMS software is used to calculate mode shapes and natural frequencies of the joined shell structure. The natural frequencies and mode shapes are calculated numerically and they are compared with those of the FEM and modal test to confirm the reliability of the analytical solution. The effects of the shallowness and length of the cylindrical shell to the free vibrational behavior of joined shell structure and the effect of internal pressure on the modal charactristics are investigated.

Dynamic Response of a Ring-Stiffened Cylindrical Shell Subjected to Underwater Explosive Loading

2011 ◽  
Vol 105-107 ◽  
pp. 931-936 ◽  
Author(s):  
Jian Hong Yuan ◽  
Xi Zhu
Keyword(s):  
Cylindrical Shell ◽  
Dynamic Response ◽  
Underwater Explosion ◽  
Simulation Method ◽  
Attack Angle ◽  
Element Analysis ◽  
Stiffened Cylindrical Shell ◽  
Test Conditions ◽  
Explosion Load ◽  
Submergence Depth

Choosing scaled stiffened cylindrical shell model as simulation object, the simulation model of stiffened cylindrical shell subjected to underwater explosion load is built by using MSC-DYTRAN finite element analysis software, the typical test conditions which shock factor is 1.1 is simulated, the damage properties of stiffened cylindrical Shell is analyzed, numerical results are compared with experimental data, it is proved that the simulation method is effective and feasible. By performing a series of numerical experiments, the influence of attack angle of explosive and submergence depth of model on the elastic-plastic dynamic response were investigated. It is shown that angle of 90 degrees is the most serious attack angle, angle of 0 degrees is less serious than other angle, the submergence depth of stiffened cylindrical shell has obvious influence on dynamic response, the more deep cylindrical shell is, the more serious cylindrical shell is damaged.

scholarly journals A SERS Study of Charge Transfer Process in Au Nanorod–MBA@Cu2O Assemblies: Effect of Length to Diameter Ratio of Au Nanorods

Nanomaterials ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 867
Author(s):  
Lin Guo ◽  
Zhu Mao ◽  
Sila Jin ◽  
Lin Zhu ◽  
Junqi Zhao ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Shell Structure ◽  
Shell Structures ◽  
Core Shell ◽  
Absorption Bands ◽  
Au Nanorods ◽  
The Core ◽  
Band Position ◽  
Surface Enhanced Raman ◽  
Core Shell Structure

Surface-enhanced Raman scattering (SERS) is a powerful tool in charge transfer (CT) process research. By analyzing the relative intensity of the characteristic bands in the bridging molecules, one can obtain detailed information about the CT between two materials. Herein, we synthesized a series of Au nanorods (NRs) with different length-to-diameter ratios (L/Ds) and used these Au NRs to prepare a series of core–shell structures with the same Cu2O thicknesses to form Au NR–4-mercaptobenzoic acid (MBA)@Cu2O core–shell structures. Surface plasmon resonance (SPR) absorption bands were adjusted by tuning the L/Ds of Au NR cores in these assemblies. SERS spectra of the core-shell structure were obtained under 633 and 785 nm laser excitations, and on the basis of the differences in the relative band strengths of these SERS spectra detected with the as-synthesized assemblies, we calculated the CT degree of the core–shell structure. We explored whether the Cu2O conduction band and valence band position and the SPR absorption band position together affect the CT process in the core–shell structure. In this work, we found that the specific surface area of the Au NRs could influence the CT process in Au NR–MBA@Cu2O core–shell structures, which has rarely been discussed before.

Sign in / Sign up

Export Citation Format

Share Document