Abstracts of Journal Articles - Accepted for Publication


Aeroelasticity of Compliant Span Morphing Wings

Authors
RM Ajaj (United Arab Emirates University, UAE) & MI Friswell (Swansea University)
Journal
Smart Materials and Structures
accepted for publication
Abstract
A low-fidelity aeroelastic model is developed to study the dynamic behaviour of uniform, cantilever span morphing wings. The wing structure is modelled using the shape functions of the bending and torsional modes of a uniform cantilever wing according to the Rayleigh-Ritz method. Theodorsen's unsteady aerodynamic theory is used to model the aerodynamic loads. A Padé approximation for the Theodorsen's transfer function is utilised to allow time-domain simulation and analysis. The sensitivity of the aeroelastic behaviour of span morphing wings to different geometric parameters and mechanical properties is considered. Furthermore, the impact of morphing rate on the aeroelastic behaviour is studied. Finally, the use of two novel span morphing concepts for flutter suppression is assessed.

A Robust Design of an Innovative Shaped Rebar System Using a Novel Uncertainty Model

Authors
N Aldoumani, H Haddad Khodaparast, C Giannetti, Z Abdallah, I Cameron, MI Friswell & J Sienz (Swansea University)
Journal
Structural and Multidisciplinary Optimization
accepted for publication
Abstract
The Co-tropic rebar system, which is a modification of the standard steel reinforcing bar in concrete matrices, has been modeled and optimized in the presence of uncertainty. This novel rebar system provides an improvement of 40-70% in the bond strength when compared to the conventional systems under pull-out conditions. The study of the design parameters of this system was carried out utilizing a novel uncertainty model that has recently been developed at Swansea University. The importance of this invention comes from the fact that the whole process has been automated by linking ANSYS Workbench to MATLAB via the in-house written code. This has facilitated the use of a huge number of trials as well as reducing the number of parameters to be studied through the selection of the most sensitive ones. The uncertainty in the design parameters of this rebar system is of a paramount importance in order to optimise the bond strength between the Co-tropic rebar system and the concrete matrix as well as to fully understand the behaviour of the proposed system under pull-out conditions. The interface between the rebar and the concrete matrix was assumed as a 'cohesive zone' whereby the interfacial area is studied as a function of the bonding strength.

Development of a Morphing Wingtip Based on Compliant Structures

Authors
C Wang, H Haddad Khodaparast, MI Friswell, AD Shaw, Y Xia (Swansea University) & P Walters (University of the West of England)
Journal
Journal of Intelligent Material Systems and Structures
accepted for publication
Abstract
Compliant structures, such as flexible corrugated panels and honeycomb structures, are promising structural solutions for morphing aircraft. The compliant structure can be tailored to carry aerodynamic loads and achieve the geometry change simultaneously, while the reliability of the morphing aircraft can be guaranteed if conventional components and materials are used in the fabrication of the morphing structure. In this paper, a compliant structure is proposed to change the dihedral angle of a morphing wingtip. Unsymmetrical stiffness is introduced in the compliant structure to induce the rotation of the structure. Trapezoidal corrugated panels are used, whose geometry parameters can be tailored to provide the stiffness asymmetry. An equivalent model of the corrugated panel is employed to calculate the deformation of the compliant structure. To provide the airfoil shape a flexible honeycomb structure is used in the leading and trailing edges. An optimisation is performed to determine the geometry variables, while also considering the actuator requirements and the available space to install the compliant structure. An experimental prototype has been manufactured to demonstrate the deformation of the morphing wingtip and conduct basic wind tunnel tests.