Secondary effects of inplane shear stress on torsional buckling on nonprismatic thin-walled members | |
| Author | Thumanoon Susumpow |
| Call Number | AIT Thesis no.ST-90-19 |
| Subject(s) | Thin-walled structures Buckling (Mechanics)--Mathematical models |
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering, School of Engineering and Technology |
| Publisher | Asian Institute of Technology |
| Abstract | Stability of thin-walled I column has been an interesting subject of study since Vlasov developed a set of differential equations for this class of problems. Many subsequent researches were based on Vlasov's theory. An interesting results were obtained when these equations were applied to axially loaded bisymmetric I columns with variable flange width. The critical loads corresponding to the uncoupled torsional buckling mode of these columns fall outside the reasonable range. This range is bounded by the critical loads of two similar columns with a constant flange width equal respectively to the largest and the smallest flange widths of the variable column. This phenomenon is contradictory to engineer's common sense which still requires explanation. Confirmation of the existence of this phenomenon was also made by finite element method. However, many assumptions were employed in developing these finite elements. In this study, an attempt is made to further investigate this paradox by using a more generic finite element for thin-walled members. By a thorough investigation, no paradox is observed on the results of the present finite element model. Further examinations found that in all previous models of thin-walled members based on Vlasov's theory, secondary effects of the inplane shear stress induced by the axial force acting on a column with variable cross-section are missing in the formulation of the geometric stiffness. This is indeed the main cause of the paradox. By adding the inplane shear terms to the geometric stiffness of a previous model, the new result does not reveal any paradox. It also agrees well with the present solution. |
| Year | 1990 |
| Type | Thesis |
| School | School of Engineering and Technology (SET) |
| Department | Other Field of Studies (No Department) |
| Academic Program/FoS | Structural Engineering (STE) /Former Name = Structural Engineering and Construction (ST) |
| Chairperson(s) | Worsak Kanok-Nukulchai |
| Examination Committee(s) | Karasudhi, Pisidhi ; Horii, Hideyuki |
| Scholarship Donor(s) | Japanese Government |
| Degree | Thesis (M.Eng.) - Asian Institute of Technology, 1990 |