A panel method based aerodynamic code for analysis of wind turbine blades

The size of commercial wind turbines has increased dramatically in the last 25 years from approximately a rated power of 50kW and a rotor diameter of 10–15m up to today’s commercially available 5MW machines with a rotor diameter of more than 120 m. This development has forced the development of reliable numerical tools which enable the prediction of steady and unsteady aerodynamic loads not only in the wind turbine blades but also in the entire wind turbine construction, including tower, drive train, rotor and control system. Within this context, this paper presents a steady-state panel method formulation based code for aerodynamic load prediction in wind turbine blades. The formulation is fully three-dimensional accounting for wake and rotational angular speed effects. A 2MW wind turbine blade has been taken as a study case to demonstrate the code capabilities.Facultad de Ingenierí

The structural behaviour of composite laminates manufactured using resin infusion under flexible tooling

EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Mode I Interlaminar Fracture Toughness Analysis of Co-Bonded and Secondary Bonded Carbon Fiber Reinforced Composites Joints

<div><p>Aiming to reduce aircraft weight, aeronautic industry seeks alternative materials and processes used to join its different structural parts. An option to traditional methods are high performance adhesive joints, which reduce weight, number of parts and component final cost, also resulting in higher strength structures. Although, the lack of experimental data to provide a detailed structural characterization of these joining techniques had limited their commercial application. The proposal of this work is to investigate the Mode I interlaminar fracture toughness under quasi-static loading using DCB specimens of carbon composite joints made by co-bonding and secondary bonding techniques, the latter giving more reliable results. For a better understanding on the failure in the systems, DSC and microscopy techniques were applied, from which three stages of delamination process during testing were observed: 1st Stage) Cohesive failure represented by an unstable crack propagation from a high energy level; 2nd Stage) transition from cohesive to adhesive and final intralaminar failure mode with lower energy levels than Stage 1; and 3rd Stage) completely stable propagation at low energy levels (delamination migrates from intralaminar to interlaminar, entirely in the substrate).</p></div