On free vibration analysis of thin-walled beams axially loaded

In this paper, a numerical–experimental study about natural frequencies of thin-walled beams axially loaded is presented. Moreover, the influence of axial load in the frequencies is studied. The equations of motion are based on Vlasov’s theory of thin-walled beams, which were modified previously to include the effects of shear flexibility, rotatory inertia in the stress resultants. Moreover, a constant axial load is incorporated to the formulation, both in the time and frequency domain. The differential equations are shown to be particularly suitable for analysis in the frequency domain using a state variables approach. A numerical investigation is carried out to reveal the influence of the axial load in several boundary conditions. Finally, free vibration experimental tests are presented, which allow verify the theory presented in this paper and provide good quality data that can be used for checking the accuracy and reliability of different theories.