Theoretical and experimental investigation of thin-walled structural elements under various load actions

Fahmy, Farouk O (1957) Theoretical and experimental investigation of thin-walled structural elements under various load actions. PhD thesis, University of Glasgow.

Abstract

Thin-walled structural forms exhibit in their behaviour under compressive actions, features normally suppressed by the heavy section outlines used in hot rolled constructions. Thus, over-all instability under a combination of torsion and flexure, is obtained in a much wider range than in hot rolled sections; and local instability, i.e., buckling of the plate components (flange or web), disregarded in hot rolled construction becomes one of the chief characteristics of thin-walled behaviour. The subject-matter of the thesis deals with these two forms of instability both theoretically and experimentally. The contents of the thesis are divided into 4 main parts, each part being further subdivided into convenient sections. Part I presents a critical review of published work relevant to: (i) over-all instability in torsion-flexure, and (ii) local instability of plate components of struts in flexure. This reveals the absence of theoretical treatment of: (i) mixed boundary conditions in torsional-flexural buckling, e.g., a hinged end strut with warping restraint, and (ii) the determination of the critical stress in local buckling of plates subjected to linearly varying compressive load actions, applicable to the plate components of structural sections subjected to eccentric axial loading. There also appears to be a scarcity of experimental investigations in this latter field. The review is followed by the theoretical analysis presented in Part II. This develops an iterative method of general application to problems of instability. The method is first applied to the derivation of the torsional-flexural buckling load for mixed boundary conditions not hitherto solved, such as the combination of hinged ends with warping restraint. The second application of the iteration method is the derivation of the local buckling strength of plates elastically supported along one longitudinal edge and free along the other. The loading for these boundary conditions, not hitherto considered in published literature, is an axial compressive action linearly varying across the width of the plate. This is applied to assess the strength in local instability of eccentrically loaded thin-walled channel sections. The experimental work described in Part III presents the results of some 190 strut tests to destruction. These consisted of equal and unequal angle and channel specimens of 65 S.W.P. Aluminium Alloy, 3 inches to 132 inches long. The tests were designed to investigate the effects on over-all and local buckling of the variation of load eccentricity, length, section profile and method of manufacture (cold formed versus extruded). In Part IV the results obtained are analysed and compared with the theory showing good agreement. The textual part of the thesis concludes with a Summary which draws attention to the main features of instability conditions investigated, as indicated by the theory and confirmed by the experimental work. The thesis concludes with a Bibliography, followed by 7 Appendices in which the details of various aspects of the work are presented.

• Item Type: Thesis (PhD)
• Qualification Level: Doctoral
• Additional Information: Adviser: A ST Thomson
• Keywords: Civil engineering
• Date of Award: 1957
• Depositing User: Enlighten Team
• Unique ID: glathesis:1957-73575
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 14 Jun 2019 08:56
• Last Modified: 14 Jun 2019 08:56
• URI: https://theses.gla.ac.uk/id/eprint/73575