Axisymmetric Free Vibration of Layered Cylindrical Shell Filled with Fluid

The aim of the study is to analyse the axisymmetric free vibration of layered cylindrical shells filled with a quiescent fluid. The fluid is assumed to be incompressible and inviscid. The equations of axisymmetric vibrations of layered cylindrical shell filled with fluid, on the longitudinal and transverse displacement components are obtained using Love’s first approximation theory. The solutions of displacement functions are assumed in a separable form to obtain a system of coupled differential equations in terms of displacement functions. The displacement functions are approximated by Bickley-type splines. A generalized eigenvalue problem is obtained and solved numerically for a frequency parameter and an associated eigenvector of spline coefficients. Two layered shells with three different types of materials under clamped-clamped boundary conditions are considered. Parametric studies are made on the variation of the frequency parameter with respect to length-to-radius ratio and length-to-thickness ratio.

Why and how Did a Multi-Layered Vessel Explode?

The layered cylindrical shell is one of important structures of high pressure vessels. From 1977 to 2005 there were 8 urea synthesis reactors exploded. Seven of them were layered cylindrical shell structure. Therefore, there will be much more issues come out and waiting for us to study and explore. In this paper, we take the urea synthesis reactor exploded in 2005 in China as an example to study why and how a multi-layered exploded. Through the research work, we not only concluded why and how a multilayered vessel exploded but also established a method to analyze the serious explosion accident of complex vessels such as urea synthesis reactors.

Study on Bi-Stable Behaviors of Double-Layered Cylindrical Shell

Bi-stable structure can be stable in both its extended and coiled forms. As a novel deployable structure, it shows a broad application prospect in the field of aeronautics and civil engineering, etc. Considered two cylindrical shells having the same flattening configurations, they can be closely bound together by applying external forces. And the corresponding double-layered cylindrical shell model is proposed. Expressions for the bending and stretching strain energies of the cylindrical shells are presented. Calculations show that total strain energy has two local minimal values, which reveals that the double-layered cylindrical shell has its bi-stability. The corresponding rolled-up radii are thus determined.

Dynamic thermo-elastic response of a discrete multi-layered cylindrical shell subjected to transient thermal loading

Explosion containment vessels (ECVs) are used to fully contain the effects of explosion events. A discrete multi-layered cylindrical shell (DMC) consisting of a thin inner cylindrical shell and helically cross-winding flat steel ribbons has been proposed, which has obvious advantages of fabrication convenience and low costs. The applications of ECVs are closely associated with blast and thermal loads, and thus, it is important to understand the response of a DMC under transient thermal load in order to develop a design code and operation procedures for the use of DMC as ECV. In this paper, a mathematical model for the elastic response of a DMC subjected to thermal loading due to rapid heating is proposed. Based on the axisymmetric plane strain assumption, the displacement solution of the dynamic equilibrium equations of both inner shell and outer ribbon layer are decomposed into two parts, i.e. a thermo-elastic part satisfying inhomogeneous stress boundary conditions and a dynamic part for homogeneous stress boundary conditions. The thermo-elastic part is solved by a linear method and the dynamic part is determined by means of finite Hankel transform and Laplace transform. The thermo-elastic solution of a DMC is compared with the solution of a monobloc cylindrical shell, and numerical results are presented and discussed in terms of winding angle and material parameters.