Buckling optimization of composite columns with variable thickness

Pekbey Y., Ozdamar A.

JOURNAL OF REINFORCED PLASTICS AND COMPOSITES, vol.26, no.13, pp.1337-1356, 2007 (SCI-Expanded) identifier identifier


A novel approach to the optimization of flexible columns against buckling is presented. The problem of determining the shape of the column that has possibly the largest critical buckling load of columns of a given length and volume is solved for composite materials. The objective of this study was to develop and design an optimized composite column against buckling. Determining what shape of column has the largest possible buckling load of composite column of a given length and volume was considered. Clamped-clamped supported column is an important limit case because it caused debate in many publications. Moreover, in this study, the optimization problem of the clamped-clamped column under buckling load, which was previously dealt with by Tadjbakhsh and Keller [5], Olhoff and Rasmussen [6] and Masur [7] is reinvestigated. It is also proved that the solutions of Tadjbakhsh and Keller, Olhoff and Rasmussen and Masur are not optimum for columns with clamped ends. The present model formulation considers columns for which crush is taken into account in the formulation of the column optimization problem, allowing for bimodal optimum solution. This leads to the necessity for both stability and crush criterion formulation of the optimization problem. The new proposed optimum model solution has been verified with numerical analysis using ANSYS and experimental data for columns with clamped-clamped ends. It was shown that the new proposed model was given the optimum solution for the clamped-clamped case. Detailed results are presented and discussed for clamped-clamped columns having circular cross-sectional configuration. As a result of this study, it was shown that results obtained in previous studies of variation optimum cross-sectional area for columns under compressive forces clamped-clamped ends were erroneous. The corrected optimum form was obtained and results checked by numerical calculations and experimental tests of composite columns.