scholarly journals Strain-Based Finite Element Analysis of Stiffened Cylindrical Shell Roof

2017 ◽  
Vol 5 (4) ◽  
pp. 225 ◽  
Author(s):  
Attia Mousa
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Cylindrical Shell ◽  
Element Analysis ◽  
Stiffened Cylindrical Shell

Benchmark of Plate Forming and Weld Distortion Process

2005 ◽  
Vol 128 (3) ◽  
pp. 414-419
Author(s):  
James Gombas
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Cylindrical Shell ◽  
Large Deflection ◽  
Element Analysis ◽  
Manufacturing Simulation ◽  
Simulation Process ◽  
Weld Distortion ◽  
Deflection Theory ◽  
Large Deflection Theory

A circular flat plate with a perforated central region is to be formed by dies into a dome and then welded onto a cylindrical shell. After welding, the dome must be spherical within a narrow tolerance band. This plate forming and welding is simulated using large deflection theory elastic-plastic finite element analysis. The manufacturing assessment is performed so that the dies may be designed to compensate for plate distortions that occur during various stages of manufacturing, including the effects of weld distortion. The manufacturing simulation benchmarks against measurements taken at several manufacturing stages from existing hardware. The manufacturing simulation process can then be used for future applications of similar geometries.

scholarly journals Dynamic instability of a compound nanocomposite shell

2021 ◽  
Vol 27 (5) ◽  
pp. 60-70
Author(s):  
N.H. Sakhno ◽  
◽  
K.V. Avramov ◽  
B.V. Uspensky ◽  
◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Cylindrical Shell ◽  
Supersonic Flow ◽  
Uniform Distribution ◽  
Critical Pressure ◽  
Natural Frequencies ◽  
Dynamic Instability ◽  
Element Analysis

Free oscillations and dynamic instability due to supersonic airflow pressure are investigated in a functional-gradient compound composite conical-cylindrical shell made of a carbon nanotubes-reinforced material. Nanocomposite materials with a linear distribution of the volumetric fraction of nanotubes over the thickness are considered. Extended mixture rule is used to estimate nanocomposite’s mechanical characteristics. A high-order shear deformation theory is used to represent the shell deformation. The assumed-mode technique, along with a Rayleigh-Ritz method, is applied to obtain the equations of the structure motion. To analyze the compound structure dynamics, a new system of piecewise basic functions is suggested. The pressure of a supersonic flow on the shell is obtained by using the piston theory. An example of the dynamic analysis of a nanocomposite conical-cylindrical shell in the supersonic gas flow is considered. The results of its modal analysis using the Rayleigh-Ritz technique are close to the natural frequencies of the shell obtained by finite element analysis. In this case, finite element analysis can only be used for shells made of material with a uniform distribution of nanotubes over the thickness. The dependence of the natural frequencies of a compound shell on the ratio of the lengths of the conical and cylindrical parts is studied. The dependence of the critical pressure of a supersonic flow on the Mach numbers and the type of carbon nanotubes reinforcement is investigated. Shells with a concentration of nanotubes predominantly near the outer and inner surfaces are characterized by higher values of natural frequencies and critical pressure than the shells with a uniform distribution of nanotubes or with a predominant concentration of nanotubes inside the shell.

Nonlinear Finite Element Analysis of a Toroidal Shell With Ring-Stiffened Ribs

2010 ◽  
Author(s):  
Qing-Hai Du ◽  
Wei-Cheng Cui ◽  
Zheng-Quan Wan
Keyword(s):  
Finite Element ◽  
Cylindrical Shell ◽  
Circular Cylindrical Shell ◽  
Structural Characteristics ◽  
External Pressure ◽  
Nonlinear Finite Element ◽  
Toroidal Shell ◽  
Shells Of Revolution ◽  
Element Analysis ◽  
Stiffened Cylindrical Shell

The toroidal shell is a special type of shells of revolution, which is hardly solved by analytical method. To show the nonlinear structural characteristics of a circular toroidal shell with ring-stiffened ribs due to external pressure, both material nonlinear and geometric nonlinear Finite Element Analyses (FEA) have been presented in this paper, especially for the stability to the type of pressure hull. In the presented Finite Element Method (FEM), the elastic-plastic stress-strain relations have been adopted, and the initial deflection of toroidal shell created by manufacture was also taken into account. The analytic results eventually indicate that by nonlinear FEA such a new type of ring-stiffened circular toroidal shell could be used to a main pressure hull as the traditional ring-stiffened circular cylindrical shell, which could obtain kinds of performance in underwater engineering, such as better stability and more reserve buoyancy to the classical ring-stiffened cylindrical shell.

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