Shape memory polymers are smart materials characterized by a recoverability memory effect and a large strain, but their mechanical properties such as low stiffness need to be improved for mechanical applications with large recovering force. Researchers have reported that the characteristics of shape memory polymers can be significantly improved when the shape memory polymers are used with fiber–reinforced composite material. In this study, a carbon fiber fabric-reinforced shape memory polymer composite hinge was designed, fabricated, and characterized for space deployable structure applications. The main idea is that the carbon–epoxy composite itself and the shape memory polymer are combined, which means both epoxy resin and shape memory polymer resin are used together and the epoxy resin remains in a B-stage after curing. As such, the stiffness and shape recovery ratio are increased. The shape memory polymer composite hinge specimens with four plies of carbon fiber fabric and a shape memory polymer were prepared for the experiment. The glass transition temperature, which was 70.9°C, was determined using dynamic mechanical analyzer. The effect of temperature on shape recovery capability was investigated. We investigated the reasons of damage evolution to shape memory polymer composite tapes occurring in the folding and deploying process. To do that, damage to the hinge was observed with a USB digital microscope and a scanning electron microscopy and then explained with ABAQUS analysis. The results confirm that the shape memory polymer composite hinge is a good candidate for an antenna in spacecraft in space.
This paper describes the design and evaluation of biomimetic wing sections, wher et he trailing edges of the wing sections are actuated by the piezoceramic actuator LIPCA (lightweight piezo-composite actuator). Thermal analogy based on linear elasticity was used for the design and analysis of the wing sections. In the actuation test of the wing sections, the effective deflection angle of the trailing edge was approximately five degrees at 300 V input. The predicted and measured actuation displacements agreed very well up to an input of 150 V. However, the real actuatio nd isplacement became larger than the estimated valu ef or higher input voltages due to the material non-linearity of the lead zirconate titanate (PZT) wafer in the LIPCA. The biomimetic wing sections can be used for control surfaces of small scale unmanned aerial vehicles (UAVs). (Some figures in this article are in colour only in the electronic version)
6 April 2009 in International Journal of Control, Automation, and Systems