الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
Significant effect is observed in geometrically nonlinear analysis of plane and space structures if the Joint characteristics are taken into consideration. Two new secant and tangent stiffness expressions of a general space frame member have been developed using the conventional beam column approach. The first expression is based on semi-rigid joint with linear functions, between the joint forces, moments, and the corresponding joint deformations.
The second expression is based on semi-rigid joint with linear functions between the axial force and axial displacement as well as twisting moment and corresponding twisting angle of the joint, and polynomial function relating the bending moment and the corresponding slip rotation of the joint; M-ø relationship. This polynomial function represents the actual M-ø relationship of the joint. The general space frame member consists of five parts; namely, two rigid parts representing the size of the end joints, two springs with a certain function to represent the stiffnesses of the two joints, and the base member. The stability and bowing functions used to derive the previous two forms are expressed by power series expansion of the trigonometric functions to avoid the numerical instability that arises when the axial force approaches zero or 4 times of Euler load. In addition to the effect of the axial force and the shortening of the member due to bending moments (bowing effect), the interaction between moments and rotations about the principal axes is also included. More general representation of the boundary conditions are also included using two different coordinate systems; namely a global coordinate system and a local system at nodal points where it is required to represent the boundary conditions that cannot be represented in the global system. At these points, the equilibrium equations would be referred to that local system of axes. Newton-Raphson and Modified Newton-Raphson techniques combined with the so-called current stiffness parameter proposed by Bergan in 1978, 1980 are used to trace the entire equilibrium path of the structure A new computer program has been implemented to carry out the proposed analysis. More generalization and facilities of the input and output data to minimize the work done by the analyst are provided. In this investigation, the external loads are applied as concentrated forces and moments at the joints only, the cross section of the member is assumed doubly symmetric about the two principal axes, and the material behavior is assumed linear. Published and experimental examples are solved to check the present method of analysis as well as the present computer, program. Numerical examples on different types of structures are solved to show the effect of joint characteristics on the behavior of these structures and to compare the results obtained using different polynomial functions of M-ø relationship of the joints.