PARAMETRIC INSTABILITY OF PULTRUDED FIBER-REINFORCED POLYMER COLUMNS UNDER AXIAL HARMONIC FORCING

摘要

The parametric instability of pultrude fiber-reinforced polymer columns with a channel section under harmonic axial load is investigated in this paper. The three plates of channel section (web and two flanges) are modelled using von Karman nonlinear plate theory. The Ritz method is used to discretize the continuous structure resulting in coupled nonlinear equations of motion, which are solved numerically. Bifurcation diagrams obtained by continuation methods and Floquet theory are used to obtain the transition curves between trivial and nontrivial solutions and to study the nonlinear oscillations of the column in the unstable regions.