Shell (structure)

About: Shell (structure) is a research topic. Over the lifetime, 76960 publications have been published within this topic receiving 464975 citations.

Atoms in molecules

Abstract: A set of spherical density basis functions for atoms sodium through argon have been obtained by least squares fitting of the corresponding electron density function for the ground state. These density functions, conveniently scaled, can be used in electron population analysis of molecules. To make this population analysis more flexible the density basis functions are split into two inner (K and L shell) parts and one outer (M shell) part. This technique gives populations which are relatively independent of the orbital bases used in spanning the molecular wavefunction. These density functions can be easily converted to scattering factors to be used in similar population analysis of accurate X-ray diffraction data.

A formulation of general shell elements—the use of mixed interpolation of tensorial components†

Abstract: We briefly discuss the requirements on general shell elements for linear and nonlinear analysis in practical engineering environments, and present our approach to meet these needs. We summarize and give further insight into our formulation of a 4-node shell element using a mixed interpolation of tensorial components, and present a new 8-node element using this approach. Specific attention is given to the general applicability of the elements and their efficient use in practice.

Surgical instrument with curvilinear tissue-contacting surfaces

Abstract: A surgical stapling instrument including a handle assembly, an elongated body portion, a shell assembly and an anvil assembly. The elongated body portion extends distally from the handle assembly and defines a longitudinal axis. The shell assembly is disposed adjacent a distal end of the elongated body portion and includes a non-planar, tissue-contacting surface oriented obliquely with respect to the longitudinal axis. The anvil assembly includes a non-planar, tissue-contacting surface oriented obliquely with respect to the longitudinal axis. The tissue-contacting surface of the anvil assembly is configured to align with the tissue-contacting surface of the shell assembly when the anvil assembly and shell assembly are in the approximated position.

The Theory of Shells and Plates

Abstract: A plate and more generally a shell is a special three-dimensional body whose boundary surface has special features. Although we defer defining a shell-like body in precise terms until Sect. 4, for the purpose of these preliminary remarks consider a surface—called a reference surface—and imagine material filaments from above and below surrounding the surface along the normal at each point of the reference surface. Suppose further that the bounding surfaces formed by the end points of the material filaments are equidistant from the reference surface. Such a three-dimensional body is called a shell if the dimension of the body along the normals, called the thickness, is small. A shell is said to be thin if its thickness is much smaller than a certain characteristic length of the reference surface, e.g., the minimum radius of the curvature of the reference surface for initially curved shells.2

Theory of Shell Structures

Abstract: Shell structures form key components in a very wide range of engineering enterprise. The theory of shell structures is an old and large subject, with a huge literature. However, this book is not a compilation of results from the past. Instead, it is an attempt to bring the essence of the subject within the grasp of engineers. It tackles the fundamental question of how bending and stretching effects combine and interact in shell structures from a physical point of view; and it shows that this approach leads to an understanding of the structural mechanics of shells in general, and to useful results in particular problems. The first half of the book is concerned mainly with the basic ideas and equations of equilibrium, geometry and elasticity, and their combination in various useful ways. In particular, it includes a simple treatment of the geometry of general curved surfaces. The second half of the book first investigates the behaviour of various practical shell structures under static loading. Then there are chapters on the buckling of shells, on vibration, and on the application of plastic theory to analysis and design.