We consider an ideal gas of infinitely rigid rods near a perfectly repulsive wall, and show that the interfacial tension of a surface with rods on one side is lower when the surface bends towards the rods. Surprisingly we find that rods on both sides of surfaces also lower the energy when the surface bends. We compute the partition functions of rods confined to spherical and cylindrical open sh...

This study deals with the vibrational behavior of two joined cross-ply laminated conical shells. Natural frequencies and mode shapes are investigated. Joined conical shells can be considered as a general case for joined cylindrical-conical shells, joined cylinderplates or cone-plates, cylindrical and conical shells with stepped thicknesses and also annular plates. Governing equations are obtain...

Gaussian mixture models (GMM) and support vector machines (SVM) are introduced to classify faults in a population of cylindrical shells. The proposed procedures are tested on a population of 20 cylindrical shells and their performance is compared to the procedure, which uses multi-layer perceptrons (MLP). The modal properties extracted from vibration data are used to train the GMM, SVM and MLP....

The aim of this study is to investigatethe effective parameters on vibrations of circular cylindrical shells with fixed rotary speed andresting elastic foundation by means of analytical and finite element numerical simulation. First, the governing equations are derived using the theory of Donnell, considering the centrifugal forces,Coriolis acceleration, and the initial annular tension. Then, t...

The fundamental frequencies and mode shapes of steel and carbon fiber–reinforced plastic (CFRP) cylindrical shells with steel inserts were investigated using finite element analysis and modal testing. The free-free boundary condition was tested with modal testing using the roving hammer method and verified by finite element analysis using ABAQUS. The results show good agreement between the test...

Buckling strength of composite latticed cylindrical shells is one of the important parameters for studying the failure of these structures. In this paper, new governing differential equations are derived for latticed cylindrical shells and their critical buckling axial loads. The nested structure under compressive axial buckling load was analyzed. Finite Element Method (FEM) was applied to mode...

In this study, the torsional stability analysis is presented for thin cylindrical with the functionally graded (FG) middle layer resting on the Winker elastic foundation. The mechanical properties of functionally graded material (FGM) are assumed to be graded in the thickness direction according to a simple power law and exponential distributions in terms of volume fractions of the constituents...

In cylindrical shells, the lowest natural frequency is not necessarily associated with the lowest wave index. In fact, the natural frequencies do not fall in ascending order of the wave index either. Solution of the vibration problem of cylindrical shells also indicates repeated natural frequencies. These modes are referred to as double peak frequencies. Mode shapes associated with each one of ...

Buckling analysis of thin cylindrical shells is very important due to their production process.  Usually longitudinal and transversal stiffeners are used to increase the buckling stiffness. In this paper, considering a thin cylindrical shell with longitudinal and transversal ribs subjected to axial force and lateral pressure, the influence of different aspect of axial force to lateral pressure ...