6926475977

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Engrg.. 110 (1), pp 75-89 (Jan 1984} 12 figs. 1 table. 12 refs

Kay Worda: Shells. Harmonie excrtation

It it shown that hyperboloid shells can be inexpensively analyzed under tha action of concentrated loads using an axiaymmetric program. The numerical anaiyses point out that a negative curvature shell under the action of a concentrated load tangent to the meridian develops important bending moment a and out of piane sheers as a condition for the distribution of the concentrated k>ad throughout the Shell.

on an element level and does not co m pro misę the consistency of the equations. The geometrie nonlinearitiesare treeted by using a corotational description wherein a coordinate system that rotates with the materiał is embedded at the integration point; thus the algorithm is directly applicable to anisotropic materials without 8ny oorrections for frame invariance of materiał property tensors. This algorithm can treot about 200 element-time-steps per CPU second on a CYBER 170/730 Computer in the explicit time integration modę.

84-1734

Aayrametric Modes and Associated Eigenyałues for Spherical Shella

A. V. Singh and S. Mirza

Ontario Hydro, Toronto. Ontario, Canada, ASME Paper No. 83-WA/PVP-8

Key Words: Shells, Spheridsl shells, Asymmetrk; excitation, Finite element technique, Transverse shear deformation effects, Rotatory inertia effects

Frea asymmetric vibration of spherical shells with clamped and hinged boundary conditions are analyzed using FEM. Element stiffness and consistent mass matrices are derived using tha improved shell theory, which takes into account tha effects of shear deformation and rotary inertia.

84-1736

Anałysia of Circular Folded Platę Shells under Axially Symmetric Loads

Liu Kałguo

J. Bldg. Struć.,_4_(3). pp 12-19 (1983)

CSTA No. 624-83.56

Key Words: Shells, Axial excitatk>n

The static, dynamie, and limit analysis of circular folded piąte shells under axielly symmetric loads are inyestigated. A mathematical model of static and dynamie analysis solved by finite differences and a failure pattern of limit analysis are presented.

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84-1735

Efficient Finite Element Methods for Tranaent Nonlinear Analysis of Shells

T. Belytschko

Dept. of Civil Engrg., Northwestern Univ., Evanston, IL, Rept. No. AFOSR-TR-83-1062. 175 pp (Aug 1983)

A O A136 044

Key Words: Shells, Finite element technique, Transient analysis, Algorithms

A finite element formulation and algorithm for the nonlinear analysis of the larga deflection, materially nonlinear response of knpul»łveły loaded shells is presentad. A unique faature of this algorithm is the use of o bilinear four node quadri-lataral element with single point quadrature and a simple hourgiass corrtrol which is orthogonal to rigid body modes

84-1737

Flexurai Axisymmetr»c Free Yibrationsof a Spherical Dotne: Exact Results and Approximate Solutions

H. Kunieda

Disaster Prevention Res. Inst., Kyoto Univ., Uji, Kyoto 611, Japan, J. Sound Vib.._92 (1), pp 1-10 (Jan 8. 1984) 4 figs, 4 tables, 13 refs

Key Words: Domes, Shells, Spherical shells. Natural fre-quencies. Modę shapes. Flaxural vibration

Exact expressk>ns exist for the natural frequenciesand modę shapes of tha axisymmetric free vibratk>ns of a *>herical shell or do me. However. they are not easily amenable to numer ical calculation and there are no reference standards of natural fraquencies and modes availabte for use in engi-neering. The exact solution is even less practical for analysis of re^wnse to dynamie loading. This paper provides the natural frequencies and modes for a wide rangę of co ni ca I angle, based on the exact solution. Competible with thesa results. an approximate solution is proposad which is suitable for dynamie response anelysis and which aasily provides natural frequencies and modal shapes which are accurate enough for engineering purposes.

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