Ian P Bond

Composite corrugated structures for morphing wing skin applications

Composite corrugated structures are known for their anisotropic properties. They exhibit relatively high stiffness parallel (longitudinal) to the corrugation direction and are relatively compliant in the direction perpendicular (transverse) to the corrugation. Thus, they offer a potential solution for morphing skin panels (MSPs) in the trailing edge region of a wing as a morphing control surface. In this paper, an overview of the work carried out by the present authors over the last few years on corrugated structures for morphing skin applications is first given. The second part of the paper presents recent work on the application of corrugated sandwich structures. Panels made from multiple unit cells of corrugated sandwich structures are used as MSPs in the trailing edge region of a scaled morphing aerofoil section. The aerofoil section features an internal actuation mechanism that allows chordwise length and camber change of the trailing edge region (aft 35% chord). Wind tunnel testing was carried out to demonstrate the MSP concept but also to explore its limitations. Suggestions for improvements arising from this study were deduced, one of which includes an investigation of a segmented skin. The overall results of this study show that the MSP concept exploiting corrugated sandwich structures offers a potential solution for local morphing wing skins for low speed and small air vehicles.

A Novel Method for the Manipulation of Damage and In-Situ Repair of Composite T-Joints

A novel method for the in-situ repair of sub critical damage in complex composite structures (T-joints) using embedded hollow vasculature has been demonstrated. A number of configurations of vascularized T-joints have been presented and assessed for their efficacy at infiltrating damage planes. The effect of vasculature on the mechanical performance of the component was assessed both numerically and experimentally. 2D and 3D thermo-mechanical finite element (FE) analyses were performed to determine the influence of vasculature on thermal residual stresses and joint strength under 90° tensile (pull-off) loading. Failure loads and damage mechanisms observed during the mechanical testing agreed well with the analysis. All configurations of deltoid vasculature were successful in infiltrating the damage sites with an injected liquid. Further optimization is required, however, the vascularized deltoid configuration shows considerable promise for future industrial adaptation.

Manufacture of magnetically active fiber reinforced composites for use in power generation

A major issue yet to be resolved for embedding sensors, actuators and microelectromechanical systems (MEMS) in smart structures is that of providing power. Work is ongoing in the field with examples of micro battery technology, use of solar power and micro fuel cells. The work presented here considers a technology to enable the development of integrated power generation and actuation. Magnetic fibre reinforced composite material has been developed which utilises hollow glass fibres filled with active magnetic material. The resulting material maintains structural integrity as well as providing a possible means of electrical power generation from a dynamically loaded structure. The hollow glass fibres were manufactured in-house using a bespoke fibre drawing facility. Hard magnetic powder materials were introduced into the hollow fibre cores to provide an active electromagnetic function. This paper will discuss the manufacture, characterization and optimisation of active magnetic fibre reinforced composite materials.

SPIE 12th Annual International Symposium on Smart Structures & Materials: Active Materials: Behavior and Mechanics, San Diego, CA, USA, 15 March

A major issue yet to be resolved for embedding sensors, actuators and microelectromechanical systems (MEMS) in smart structures is that of providing power. Work is ongoing in the field with examples of micro battery technology, use of solar power and micro fuel cells. The work presented here considers a technology to enable the development of integrated power generation and actuation. Magnetic fibre reinforced composite material has been developed which utilises hollow glass fibres filled with active magnetic material. The resulting material maintains structural integrity as well as providing a possible means of electrical power generation from a dynamically loaded structure. The hollow glass fibres were manufactured in-house using a bespoke fibre drawing facility. Hard magnetic powder materials were introduced into the hollow fibre cores to provide an active electromagnetic function. This paper will discuss the manufacture, characterization and optimisation of active magnetic fibre reinforced composite materials.