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Showing papers on "Shell (structure) published in 1987"


Journal ArticleDOI
TL;DR: In this paper, exact solutions for laminated cylindrical shells in bending are presented for low curvature radius-to-depth ratios, and they are compared with the analogous results from classical shell theory and Donnell shell theory.

223 citations


Journal ArticleDOI
TL;DR: It is shown that mechanical tensions in the range which lyse membranes are induced at values of the external field which are of the same order as those which are reported to lyse the plasma membranes of cells in suspension.
Abstract: We analyze the electrical and mechanical stress in the bounding membrane of a cell (or vesicle) in suspension which is deformed by an external applied field. The membrane is treated as a thin, elastic, initially spherical, dielectric shell and the analysis is valid for frequencies less than the reciprocal of the charging time (i.e. less than MHz), or for constant fields. A complete analytic solution is obtained, and expressions are given which relate the deformation, the surface tension and the transmembrane potential difference to the applied field. We show that mechanical tensions in the range which lyse membranes are induced at values of the external field which are of the same order as those which are reported to lyse the plasma membranes of cells in suspension.

121 citations



Journal ArticleDOI
TL;DR: In this paper, a theory for obtaining the propagation constants of a thin uniform cylindrical shell, periodically stiffened by uniform circular frames of general cross-section, is developed.

105 citations


Journal ArticleDOI
TL;DR: In this paper, a hybrid-strain-based lower order shell element is proposed for modeling and analysis of layerwise anisotropic shell structures undergoing large deformation of finite strains and finite rotations.

102 citations


Journal ArticleDOI
TL;DR: In this article, a new shell element, which is free from serious locking problems and which does not possess hourglass modes, is proposed, which exhibits good convergence for plates with variable thickness.
Abstract: A new shell element, which is free from serious locking problems and which does not possess hourglass modes, is proposed. Solutions obtained with this element exhibit good convergence and are satisfactorily insensitive to mesh distortion. The element also exhibits good convergence for plates with variable thickness. This element is based on the use of assumed covariant strains which are obtained from the covariant strain field defined with respect to the element natural co-ordinate system. Only the linear version for thin shell cases is considered. The element performance is tested by application to several standard plate and shell problems. A problem involving variable thickness is also presented.

96 citations


Journal ArticleDOI
TL;DR: In this paper, a nine node shell element is developed by a new and more efficient mixed formulation, which is based on the Hellinger-Reissner principle with independent strain and the concept of degenerate solid shell.
Abstract: : A nine node shell element is developed by a new and more efficient mixed formulation. The new shell element formulation is based on the Hellinger-Reissner principle with independent strain and the concept of degenerate solid shell. The new formulation is made more efficient in terms of computing time than the conventional mixed formulation by dividing the assumed strain fields into a lower part and a higher order part. Numerical results demonstrate that the present nine node element is free of locking even for very thin plates and shells and is also kinematically stable. In fact the stiffness matrix associated with the higher order assumed strain plays the role of a stabilization matrix.

80 citations


Patent
16 Apr 1987
TL;DR: In this article, an improved stand-off device is proposed to control the spacing between adjacent planar elements in electronic instrumentation, which includes a resilient, hollow shell member and a rigid, cylindrical inner element.
Abstract: An improved stand-off device is disclosed which is used to control the spacing between adjacent planar elements in electronic instrumentation. The stand-off device includes a resilient, hollow shell member and a rigid, cylindrical inner element. The shell member has at least one slot extending from one end, and has a top interior cylindrical surface, a bottom interior cylindrical surface, and a threaded intermediate interior surface. The inner element has a conical expander portion and a drive portion with a threaded exterior surface which is complementary to the threaded interior intermediate surface of the shell member. The slotted end of the shell member is adapted for insertion into an aperture in a planar member from one side of that member. The inner element is adapted for insertion into the shell member from the same side of that member, whereupon the conical portion forces the slotted end of the shell member to expand and engage the perimeter of the aperture in the planar member.

76 citations


01 Jul 1987
TL;DR: The DYNA3D as mentioned in this paper is an explicit three-dimensional finite element code for analyzing the large deformation dynamic response of inelastic solids and structures, which includes twenty-five material models and eleven equations of state to cover a wide range of material behavior.
Abstract: This report provides an updated user's manual for DYNA3D, an explicit three-dimensional finite element code for analyzing the large deformation dynamic response of inelastic solids and structures. A contact-impact algorithm permits gaps and sliding along material interfaces with friction. By a specialization of this algorithm, such interfaces can be rigidly tied to admit variable zoning without the need of transition regions. Spatial discretization is achieved by the use of 8-node solid elements, 2-node beam elements, 4-node shell elements, 8-node solid shell elements, and rigid bodies. The equations-of-motion are integrated in time by the central difference method. DYNA3D contains twenty-five material models and eleven equations of state to cover a wide range of material behavior.

75 citations


Patent
17 Feb 1987

74 citations


Journal ArticleDOI
TL;DR: In this article, a very simple and practical formulation and procedure to remove the restriction of small rotations between two successive increments for geometrically nonlinear analysis of shells using flat triangular shell elements is presented.

Journal ArticleDOI
TL;DR: In this paper, a quadrilateral shell element consisting of five nodes, four corner nodes and a central node is developed for linear elastic analysis of thin as well as moderately thick shells.

Journal ArticleDOI
TL;DR: In this paper, an efficient and accurate 3D finite element model which may be used in the nonlinear analysis of reinforced concerete plate and shell structures is presented. But the model is not suitable for the non-linear analysis in the case of finite element models.

Patent
02 Mar 1987
TL;DR: In this paper, a helmet with two-way radio communication faculty including a cap-like outer shell made of hard and electrically insulating plastic material, an ear-pad member secured to one side edge of the outer shell, a transmitter unit arranged in a top recess formed in an outer surface of the shock absorbing member at its top portion, a receiver unit arranged on an inner surface of an earpad member, a battery unit arranged inside a side recess forming in the outer surface, opposite to a side on which the ear pad member is secured.
Abstract: A helmet with two-way radio communication faculty including a cap-like outer shell made of hard and electrically insulating plastic material, a cap-like shock absorbing member arranged within the outer shell, an ear-pad member secured to one side edge of the outer shell, a transmitter unit arranged in a top recess formed in an outer surface of the shock absorbing member at its top portion, a receiver unit arranged on an inner surface of the ear-pad member, a battery unit arranged in a side recess formed in the outer surface of the shock absorbing member at its side which is opposite to a side on which the ear-pad member is secured to the outer shell, a transmitting dipole antenna made of a metal foil secured on an inner surface of the outer shell at its one side with the aid of an electrically insulating adhesive tape, and a receiving dipole antenna made of a metal foil secured on the inner surface of the outer shell at its other side with the aid of an electrically insulating adhesive tape.

Journal ArticleDOI
TL;DR: In this paper, the influence of thickness shear deformation and rotatory inertia on the free vibrations of antisymmetric angle-ply laminated circular cylindrical panels is investigated.

Patent
06 Oct 1987
TL;DR: An insulating shell and carrier for a bottle in which the shell is formed of an insulating material having a main body section with an opening into which the bottle fits and an integral handle portion having an opening to permit a user to carry the bottle by the shell to use it as a pouring aid is described in this paper.
Abstract: An insulating shell and carrier for a bottle in which the shell is formed of an insulating material having a main body section with an opening into which the bottle fits and an integral handle portion having an opening to permit a user to carry the bottle by the shell to use it as a pouring aid. The shell is preferably made from a flat sheet of material which is cut to the desired shape and size and joined at the edges to form the configuration matching that of the bottle.

Journal ArticleDOI
TL;DR: The history of the development of finite elements for shell analysis is reviewed in this paper with emphasis on innovations that improved quality, and the effects of transverse shear flexibility on the accuracy of p elements are examined.

Journal ArticleDOI
TL;DR: In this article, a finite element formulation for three dimensional curved shell heat conduction where nodal temperatures and nodal temperature gradients through the shell thickness are retained as primary variables is presented.

Patent
18 Dec 1987
TL;DR: In this paper, a method of constructing a swimming pool by laying a concrete shell of 80 mm thickness without any substantial reinforcement is presented, where a glass reinforced plastic of 5 mm thickness is then laid over the concrete once the concrete has cured.
Abstract: A method of constructing a swimming pool by laying a concrete shell of 80 mm thickness without any substantial reinforcement A glass reinforced plastic of 5 mm thickness is then laid over the concrete once the concrete has cured This particular combination between the fiberglass and the concrete shell allows the shell to crack and move in relation to the reinforced plastic layer, without transmitting any stresses to the reinforced plastic layer This results in a pool which allows any stresses due to soil subsidence, movement, etc to be transmitted to the concrete shell and not the reinforced plastic layer thereby leaving the plastic layer free of cracks

Journal ArticleDOI
TL;DR: In this paper, a doubly curved quadrilateral Love-Kirchhoff shell finite element is used to study the dynamic weakening of shell structures under a general class of time-dependent loadings.
Abstract: Structural buckling under dynamic loads may occur at load levels that are less than the corresponding static loads. Presence of local geometric imperfections may induce an early buckling for both static and dynamic loadings. The phenomenon of "dynamic weakening" is studied for a general class of shell structures under a general class of time-dependent loadings. A doubly curved quadrilateral Love-Kirchhoff shell finite element is used. Geometric deviations of the shell middle surface are included within the element formulation by suitably modifying the strain-displacement relations. This is accomplished by retaining additional terms that are quadratic in spatial derivatives of imperfections and displacement components. The nonlinear equations of motion are written in the Lagrangian system and are solved by using an incremental algorithm based on Newmark's generalized operator. The dynamic responses up to buckling are obtained for a perfect spherical cap and an imperfect spherical cap both under external pressure, as well as a complete imperfect sphere under external pressure. Numerical results include the effects of amplitude of imperfection and thickness of shell on the dynamic buckling loads. The formulation is general and can be applied to obtain the dynamic buckling responses of a wide variety of shell structures.

Journal ArticleDOI
TL;DR: In this article, a theoretical analysis for the free vibration of simply supported vertical cylindrical shells partially filled with or submerged in a fluid has been developed, where the Rayleigh-Ritz technique is used to obtain an approximate solution which coincides with the exact solution for the cases of an empty shell or a shell completely in contact with fluid.

Patent
06 Jul 1987
TL;DR: In this paper, a cylindrical shell for each tube of length less than the tube and surrounding a substantial portion of the length of the tube, the internal nominal diameter of the shell being greater than the maximum external cross-section dimensions of the tubes, the shell having a spiral groove formed in the cylinder wall thereof, the depth of the groove being such that the interior surface of the spiral shell at the groove contacts at least part of the exterior surface of a tube thereby forming a flow path in the annular area.
Abstract: A machine for manufacturing ice including a plurality of elongated vertical tubes of uniform internal cross-sectional dimensions, a cylindrical shell for each tube of length less than the tube and surrounding a substantial portion of the length of the tube, the internal nominal diameter of the shell being greater than the maximum external cross-section dimensions of the tube, the shell having a spiral groove formed in the cylindrical wall thereof, the depth of the groove being such that the interior surface of the shell at the groove contacts at least part of the exterior surface of the tube thereby forming a flow path in the annular area between the exterior of the tube and the interior of the shell which is, at least in part, spiraled. Refrigerant gas is expanded in the tube-shell annular areas to chill the tubes. Water is introduced into the upper end of the tubes to flow downwardly through them and form in each tube a rod of ice. The tubes are then heated, such as by introducing hot gas into the annular tube-shell area to release the rods of ice which falls downwardly out the lower end of the tubes, the annular refrigerant flow path providing improved effectiveness and efficiency in chilling the tube for the formation of ice. Pivotally actuated cutter sever the rods of ice into short lengths. A diverter arrangements directs water flowing out of the tubes as ice is being formed into a reservoir and shifts to direct the produced ice out of the machine.

Patent
11 Mar 1987
TL;DR: In this article, the melting process for producing amorphous metal foils has been described, where the surface or wall is constructed as a thin-walled cylindrical shell or tube which is elastically deformable to some extent.
Abstract: During the melt spinning process for producing metal foils having an amorphous structure, molten metal is cast through a slot-like nozzle onto a surface or wall which is rapidly moved past the nozzle. A particularly rapid quenching and cooling rate of the solidifying melt is achieved by providing cooling support elements which are supplied with a cooling pressure medium, on one side of the moved surface or wall and which aide is located opposite to or remote from the nozzle. Advantageously, the surface or wall is constructed as a thin-walled cylindrical shell or tube which is elastically deformable to some extent. In its shell interior, there are provided a number of rows of cooling support elements which may be controlled by thickness sensors and temperature profile sensors. There is thus rendered possible, the continuous production of amorphous metal foils.

Patent
06 Jul 1987
TL;DR: In this paper, a one-piece outer shell made of reinforced fibreglass plastic material having core materials laminated to inside surfaces of the shell and with window and door and other openings cut through the shell, insulating materials and wall covering materials affixed to the inside surfaces.
Abstract: A sleeper cab unit for mounting on a truck comprising a one-piece outer shell made of reinforced fibreglass plastic material having core materials laminated to inside surfaces of the shell and with window and door and other openings cut through the shell and insulating materials and wall covering materials affixed to the inside surfaces of the shell.

Patent
27 Nov 1987
TL;DR: In this paper, an electrical connector includes a conductive shell (21) and electrical contacts (25, 25, 25 and 25, 27, 28, 29, 30, 31, 32, 34, 35, 36, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 70] and a ring (
Abstract: An electrical connector (10) includes a conductive shell (21) and electrical contacts (25, 25, 25, 25) extending from an edge of a corresponding conductive strip (70, 70) the length of the strip (70, 70) from which the contacts (25, 25, 25, 25) extend is overlapped by and between the shell (21) and a ring (26), and the contacts (25, 25, 25, 25) extend parallel to the thickness of the strip (70, 70) and perpendicular to the length of the strip (70, 70).

Journal ArticleDOI
TL;DR: In this article, a new finite element for modeling fiber-reinforced composite plates and shells is developed and its performance for static linear problems is evaluated and the results show that the present element yields accurate solutions for the test problems presented.

Book ChapterDOI
01 Jan 1987
TL;DR: In this paper, the derivation of a two-dimensional system of shell equations by means of the direct methods of the calculus of variations, for an elastic layer the material of which is non-uniform in thickness direction, was studied.
Abstract: We are concerned in this paper with the derivation of a two-dimensional system of shell equations by means of the direct methods of the calculus of variations, for an elastic layer the material of which is non-uniform in thickness direction. We have on earlier occasions considered this problem for transversely isotropic layers with uniform material properties in thickness direction, by means of the classical variational theorem for displacements [1], as well as by means of a variational theorem for displacements and stresses [3, 4].

Book
01 Jan 1987
TL;DR: In this paper, the basic fundamentals of the analysis and design of shell-structures are presented. But they do not cover the analysis of shell structures in the Prentice Hall International Series in Civil Engineering Engineering Mechanics.
Abstract: fundamentals-of-the-analysis-and-design-of-shell-structures-prentice-hall-international-series-in-civil-engineering-engineering-mechanics-by-kelkar-vasant-s-sewell-robert-t-1987-hardcover 1/3 PDF Literature Search and download PDF files for free. Fundamentals Of The Analysis And Design Of Shell Structures Prentice Hall International Series In Civil Engineering Engineering Mechanics By Kelkar Vasant S Sewell Robert T 1987 Hardcover


Patent
28 Jan 1987
TL;DR: In this article, a method of forming a lightweight threaded fastener element of bimaterial construction to high-tolerance requirements is presented. But this method is not suitable for high-temperature materials.
Abstract: A method of forming a lightweight threaded fastener element of bimaterial construction to high tolerance requirements, the element formed by the steps of shaping a metal shell to a preliminary configuration blank by extrusion, filling the extruded shell with a less dense material such as a curable epoxy-graphite material or an aluminum-lithium alloy, further shaping the filled blank by forging both the core material and shell to an intermediate configuration which is finished by warm rolling to form a strong lightweight fastener element configured with the metal shell thereof which may be engageable with a cooperating metal fastener assembly member.