Variable Stiffness Structures through Reversible Lamination Using Dry Adhesives

On-demand control of bending stiffness would be advantageous for deployable and adaptive space structures, addressing the conflicting requirements of large shape change and load-carrying capacity in lightweight structures. Reversible lamination approaches in layered structures are particularly intriguing for modification of bending stiffness but to date require a continuous energy input and can achieve only limited stiffness variation. Here, a new concept is proposed in which fiber reinforced polymer (FRP) layers are reversibly attached using dry adhesives and magnetic actuation. Fabrication procedures are presented for realizing hinges with variable bending stiffness and various actuation strategies for reversible lamination are evaluated. Bending test results show the expected variable stiffness response, as the dry adhesive transfers shear forces across the layers only in the bonded state. The response is passively maintained in two states with distinct stiffnesses. Preliminary results show bending stiffness ratios of up to 28 between the two states, significantly exceeding the state-of-the-art. The low-energy requirements, high stiffness variability, and simple boundary conditions, make this concept ideal for integration into large deployable or adaptive structures.