الفهرس 
CHAPTER1. REVIEW OF WORKOnly 14 pages are availabe for public view
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Abstract
In this thesis, two of the buckling problems of columns are theoretically analyzed as follows:
The analysis of columns of gradually variable cross sections under the combined action of a distributed axial load and a concentrated compressive force applied at the ends by using the minimum potential energy technique are presented. Each of the moment of inertia of the cross section and the intensity of the distributed loads varies according to a power of the distance along the column. Buckling loads and critical stresses for perfect column are given in explicit expression for a wide range of the power of the power of the moment of inertia and the intensity of the load functions. A comparison of the results with the previous theoretical studies is also given in this thesis, which clarifies the accuracy and simplicity of this method to find the required critical loads.
Also, the buckling problem of perfect column of constant cross section with holes (or with sudden change in cross section) by using the minimum potential energy technique is theoretically analyzed. The moment of inertia at the location of the hole is reduced and is taken as a certain ratio of the moment of inertia of the column. In the present work, different cases of the end conditions (pinned ends, fixed ends, simple-fixed ends and fixed –free ends) are studied.