Dynamic stability of a curved beam under sinusoidal loading

This paper is a study of snap-through properties of a non-linear dynamic buckling response to sinusoidal excitation of a clamped-clamped buckled beam. Using a simple formula, the highly non-linear motion of snap-through and its effects on the overall vibration have been studied. The non-linear governing equation obtained here is solved using the Runge-Kutta (RK-4) numerical integration method. Critical parameters at the onset of the snap-through motion, which vary with different damping coefficients and linear circular frequencies of a flat beam, are studied and given in terms of the excitation level and response displacement. The relationships between static and dynamic responses at the start of the snap-through motion are also predicted. The analysis brings out various characteristic features of the phenomenon, i.e. (a) small oscillations about the buckled position, (b) chaotic motion of intermittent snap-through and (c) large oscillations of continuous snap-through motion crossing the two buckled positions. The non-linear dynamic instability behaviour of the beam, changing from the softening spring type to the hardening type, is due to the snap-through motion.