this study aims to investigate the effects of geometric imperfections on buckling of thin cylindrical shells due to global shear. to this end, more than 320 finite element models of cylindrical shells with different diameter to thickness ratios were prepared. random imperfections with different amplitudes were applied to numerical models. the results revealed that global buckling of cylindrical...

Modern mechanical engineering sets the tasks of calculating thin-walled structures that simultaneously combine sometimes mutually exclusive properties: lightness and economy on one hand high strength reliability other. In this regard, use orthotropic materials plastics seems quite justified.The article demonstrates complex representation method equations shells general theory, which allowed in ...

Increasing observations are becoming available about a relatively weak, but persistent, non-axisymmetric magnetic field co-existing with the dominant axisymmetric field on the Sun. It indicates that the non-axisymmetric magnetic field plays an important role in the origin of solar activity. A linear non-axisymmetric α − Ω dynamo model is set up to discuss the characteristics of the axisymmetric...

The Hanle e†ect concerns the modiÐcation of polarized resonance-line scattering by magnetic Ðelds ; thus, it can be used as a diagnostic of stellar magnetic Ðelds. The Hanle e†ect has been used to determine the Ðeld strength and distribution of magnetic structures present in prominences of the Sun. To investigate its potential use in stellar astronomy, the simpliÐed case of an optically thin ax...

Observations show that solar activity is distributed non-axisymmetrically, concentrating at “preferred longitudes”. This indicates the important role of non-axisymmetric magnetic fields in the origin of solar activity. We investigate the generation of the non-axisymmetric fields and their coupling with axisymmetric solar magnetic field. Our kinematic generation (dynamo) model operating in a sph...

A dynamic statement and a method for numerically solving the buckling problems of elastoplastic shells revolution with filler in axisymmetric non-axisymmetric shapes under quasi-static loading are presented within framework two approaches. In first approach, problem elastic-plastic deformation an elastic combined torsion is formulated two-dimensional (generalized axisymmetric) formulation based...

Most hermit crabs depend on empty gastropod shells for shelter; competition for appropriate shells is often severe. This study determined whether shells that have been drilled by naticid gastropods are suitable for occupancy by the hermit crab Pagurus longicarpus. Differences in the characteristics of empty shells and those occupied by hermit crabs were assessed at two adjacent field sites in N...

The purpose of this study is to determine more accurately the marginal stability condition for axisymmetric waves since it is believed that an unstable axisymmetric wave could affect the amplification of spiral waves. An axisymmetric wave with a gradient term of velocity dispersion ( surface density ) is derived. Analysis of this axisymmetric wave with a gradient term for our own galaxy shows t...

Context. The MHD instabilities can generate complex field topologies even if the initial field configuration is a very simple one. Aims. We consider the stability properties of magnetic configurations containing a toroidal and an axial field. In this paper, we concentrate mainly on the behavior of non-axisymmetric perturbations in axisymmetric magnetic configurations. Methods. The stability is ...