One of the persistent challenges facing the development of morphing aerostructures is the need to have material and structural solutions which provide a compromise between the competing design drivers of low actuation energy and high stiffness under external loads. This work proposes a solution to this challenge in the form of a novel switchable stiffness structural concept based on the principle of granular jamming. Granular jamming is a well-known phenomenon in which particulate matter will transition from a liquid-like, smoothly flowing state to a locked, rigid state upon the application of external pressure which ‘jams’ the granular particles together. This work applies this physical principle for the first time to the design of morphing aerostructures in a manner which allows the structure to have ‘switchable stiffness’ through the application of a net pressure field to the granular core of a morphing structure or skin panel. In this paper, the concept is first introduced, followed by a discussion of possible design configurations and implementations for fixed-wing aircraft. Experiments into the flexural properties of various granular media with jamming induced by applied vacuum pressure are then presented. Four-point bending tests are used to obtain the flexural rigidity and bending stiffness of each of the materials tested. Non-linear Finite Element Analysis simulations are presented which highlight the need for detailed consideration of the micromechanics and non-linear stress-strain curves of these materials in order to adequately capture their global bending behavior. Finally, a unit cell of a bending driven switchable stiffness aerostructure is presented, and experimental bending stiffness results are compared against non-linear Finite Element Analysis.
|Published - 2018
|29th International Conference on Adaptive Structures and Technologies - Konkuk University, Seoul, Korea, Republic of
Duration: 30 Sept 2018 → 4 Oct 2018
Conference number: 29th
|29th International Conference on Adaptive Structures and Technologies
|Korea, Republic of
|30/09/18 → 4/10/18