Self-oscillating buckling and postbuckling of a liquid crystal elastomer disk under steady illumination

•A new light-fueled self-oscillating buckling and postbuckling disk is originally developed.•Two motion regimes of static regime and self-buckling regime are discovered.•The critical conditions for triggering self-buckling are calculated for different system parameters.•Results aid the design and control of self-oscillating buckling and postbuckling of the LCE disk. Self-oscillating systems can absorb energy from steady environment to maintain continuous movements without the aid of extra controller. Different from the existing abundant self-oscillating systems, self-buckling has the advantages of sudden energy explosion and large displacement, and has potential application in the fields of jumping robots, rescue, military industries, mechano-logics and so on. However, it is a challenging task in avoiding the tendency of reaching thermodynamic equilibrium for a self-oscillating system. In this paper, we creatively develop a self-oscillating liquid crystal elastomer (LCE) disk, which is capable of buckling continuously and periodically under steady illumination. Based on nonlinear plate theory and dynamic LCE model, a nonlinear dynamic model of the self-buckling LCE disk is formulated. By series expansions and Runge-Kutta method, the dynamic buckling and postbuckling of the LCE disk under steady illumination is numerically calculated. The LCE disk under steady illumination can develop into two motion regimes: the static regime and the self-buckling regime, including alternating and unidirectional self-buckling regimes. The self-buckling of the disk can be triggered by controlling several key system parameters. In addition, the frequency and amplitude of the self-buckling can also be modulated by these parameters. The self-buckling LCE disk broadens the design ideas in the fields of new robots, energy conversion, and biomimetic. [Display omitted]