Geometric Optimisation of Hinge-less Deployment System for an Active Rotorblade

The Green Rotorcraft project (part of Clean Sky JTI) is\ud studying the Gurney flap as a demonstrator of a smart adaptive\ud rotorblade. Deployment systems for the Gurney flap need to\ud sustain large centrifugal loads and vibrations while maintaining\ud precisely the displacement under aerodynamic loading. Designing\ud such a mechanism relies on both the actuation technology\ud and the link which transmits motion to the control surface. Flexible\ud beams and piezoelectric patch actuators have been chosen as\ud components to design this mechanism. Flexible beams are providing\ud an hinge-less robust structure onto which the piezoelectric\ud actuators are bonded. A candidate topology is determined\ud by investigating the compliance of a simple wire structure with\ud beam elements. A parametrized finite element model is then built\ud and optimized for displacement and force through surrogate optimization.\ud The whole process does not requires many finite element\ud analyses and quickly converge to an optimized mechanism

Vibration Based Damage Identification in a Composite T-Beam Utilising Low Cost Integrated Actuators and Sensors

The development of integrated measurement systems for composite structures is\ud urged by the fact that a Structural Health Monitoring environment requires these systems to become an integral part of the structure. The feasibility of using low cost piezoelectric diaphragms for dynamic characterisation and vibration based damage identification in a composite T-beam structure is demonstrated. The dynamic behaviour is analysed by applying these basic electronic sound components for actuation and sensing. Impact induced damage at the skin-stiffener connection is detected and localized by applying the MSE-DI algorithm on the measured bending strain mode shapes

The influence of the horn effect in tyre/road noise

The horn effect is known as an important amplification mechanism in tyre/road noise. The name is referring to the geometry between tyre and road surface which resembles an exponential horn. The horn effect is a common subject for both experimental and numerical research. Contrary to previous studies which considered point sources, this paper focusses on the horn effect by simulated tyre vibrations. The amplification of acoustic pressure, however, depends largely on the location of the observer. The sound power can be used as a measure for the horn effect which is independent on the point of observation. In this paper, the sound radiation problem is solved using the boundary element method (BEM). First, a case study considering equivalent point sources is used to validate the accuracy of the boundary element model and solver using experimental results. Next, the vibrations of tyres rolling on textured road surfaces are investigated numerically. The computed tyre vibrations are used to study the horn effect using different tyre designs. The amplification by horn effect is determined by the combined tyre/road geometry and the distribution of the noise. The current method may be used to systematically study the influence of the horn effect, for example, during tyre development