Large crystalline molecular shells, such as some viruses and fullerenes, buckle spontaneously into icosahedra. Meanwhile multicomponent microscopic shells buckle into various polyhedra, as observed in many organelles. Although elastic theory explains one-component icosahedral faceting, the possibility of buckling into other polyhedra has not been explored. We show here that irregular and regula...

Elastic stability of ring and stringer-stiffened cylindrical shells under axial, internal and external pressures is studied using Ritz method. The stiffeners are rings, stringers and their different arrangements at the inner and outer surfaces of the shell. Critical buckling loads are obtained using Ritz method. It has been found that the cylindrical shells with outside rings are more stable th...

In the present research, the elastic buckling of composite cross-ply elliptical cylindrical shells under axial compression is studied through finite element approach. The formulation is based on shear deformation theory and the serendipity quadrilateral eight-node element is used to study the elastic behavior of elliptical cylindrical shells. The strain-displacement relations are accurately acc...

This paper develops a methodology for benchmarking knowledge-based systems that practitioners may use to perform a comparative analysis of expert system shells. A program utilizing a deliberate instructional mix was found to be the most suitable and accurate way to measure the value of shells. The benchmark is intended for rule-based shells, such as CLIPS, VP-Expert and Ibis. The methodology fo...

The suspension-feeding slippersnail Crepidula convexa is commonly associated with hermit crabs (Pagurus longicarpus) living in periwinkle shells (Littorina littorea) at our study site in Nahant, MA, USA. In 15 field surveys conducted at Nahant in 2000, 2001 and 2003, we found that (1) more than 61.8% of individuals of C. convexa resided on shells occupied by hermit crabs, as opposed to the shel...

in this paper the meshless local petrov-galerkin (mlpg) method is implemented to study the buckling of isotropic cylindrical shells under axial load. displacement field equations, based on donnell and first order shear deformation theory, are taken into consideration. the set of governing equations of motion are numerically solved by the mlpg method in which according to a semi-inverse method, ...

Conventional sensors, such as proximeters and accelerometers, are add-on devices usually adding additional weights to structures and machines. Health monitoring of flexible structures by electroactive smart materials has been investigated over the years. Thin-film piezoelectric material, e.g. polyvinylidene fluoride (PVDF) polymeric material, is a lightweight and dynamic sensitive material appe...

X-ray diffraction (XRD), Scanning Electron Microscope-Energy Dispersive Spectroscopy (SEM-EDS), and Fourier Transform Infrared Spectroscopy (FT-IR), were applied to analyze the organic matrix of two Molluscan shells. The Mollusca shells are mineral structure and calcium carbonate crystallized as aragonite. The FT-IR spectra showed Alkyl Halide, Alkanes, Alcohols, Amides, Aromatic, and Hydroxyl ...

In this paper, the plastic limit load of cylindrical shells with opening subject to combined bending moment and axial force are found by finite element method using ANSYS suite of program. The effect of various parameters such as the geometrical ratios of shell and the shape, size, axial and angular position of the opening on the limit load of cylindrical shells under various loading conditions...