We present an idealised model of gravitational collapse, describing a collapsing rotating cylindrical shell of null dust in flat space, with the metric of a spinning cosmic string as the exterior. We find that the shell bounces before closed timelike curves can be formed. Our results also suggest slightly different definitions for the mass and angular momentum of the string. Introduction A stat...

Buckling of imperfect thin shell tank which is subjected to uniform axial compression is analyzed. The effect of internal pressure on the stability of a shell tank filled with a homogeneous-heterogeneous liquid was considered. Investigation of the liquid nature effect on reduction of the shell buckling load is performed by using the finite elements method. Calculating results in terms of analyt...

In this study, nonlinear analysis for thick cylindrical pressure vessels with arbitrary variable thickness made of hyperelastic functionally graded material properties in nearly incompressible state and clamped boundary conditions under non-uniform pressure loading is presented. Thickness and pressure of the shell are considered in axial direction by arbitrary nonlinear profiles. The FG materia...

A new closed form formulation of three-dimensional (3-D) refined higher-order shell theory (RHOST) to analyze the free vibration of composite circular cylindrical shells has been presented in this article. The shell is considered to be laminated with orthotropic layers and simply supported boundary conditions. The proposed theory is used to investigate the effects of the in-plane and rotary ine...

Earth dam is a structure as homogeneous or non-homogeneous forms for raising water level or water supply. Earth dam consist of different parts that one of the main parts is clay core. Choosing an optimal non permeable core which causes reduction of seepage through dam body and also being stable is necessary. The objective of this research is to optimize the geometry of earth dam clay core such ...

Using numerical and asymptotic methods, the lowest natural frequencies vibration modes of a structure consisting closed circular cylindrical shell with an end cap attached to it, having shape shallow spherical segment, are studied in paper. Three types vibrations described. Eigenfrequencies first type, close shell, were previous works. In this paper, we study forms second type (cylindrical shel...

A new method for obtaining the response of a baaed, uid{loaded, nite cylindrical shell using the nite element method is presented. The Galerkin nite element formulation for this problem utilizes a Neumann Green's function representation of the pressure loading on the shell. By representing the pressure loading in this manner, only the structure need be discretized. Both C 0 and C 1 nite element...

Cylindrical shells, unstiffened or stiffened with rings and/or stringers are commonly used in offshore structures as main loading-carrying members. Comprehensive theoretical work and experimental studies on the buckling behavior of cylindrical shells have been carried out in the past. The increasing offshore application of stiffened cylindrical shells has raised some new challenges that need to...