Passive Morphing in Aerospace Composite Structures

Attempts to add the advanced technologies to aerospace composite structures like fan blade have been on in recent times to further improve its performance. As part of these efforts, it has been proposed that the blade morph feasibility could be studied by building and optimizing asymmetric lay up of composite plies inside the blade which will help generate enough passive morphing between max cruise and climb conditions of the flight. This will have a direct efficiency (Specific Fuel Consumption) benefit. This research describes the various ideas that were tried using in house-developed lay-up optimization code and Ansys commercial software to study the possibility of generating enough passive morphing in the blade. In the end, this report concludes that the required degree of passive morphing could not be generated using various ideas with passive morphing technology and only up to some extent of morphing is shown to be feasible using the technologies used here.

A stabilized ALE method for computational fluid–structure interaction analysis of passive morphing in turbomachinery

Computational fluid–structure interaction (FSI) and flow analysis now have a significant role in design and performance evaluation of turbomachinery systems, such as wind turbines, fans, and turbochargers. With increasing scope and fidelity, computational analysis can help improve the design and performance. For example, it can help add a passive morphing attachment (MA) to the blades of an axial fan for the purpose of controlling the blade load and section stall. We present a stabilized Arbitrary Lagrangian–Eulerian (ALE) method for computational FSI analysis of passive morphing in turbomachinery. The main components of the method are the Streamline-Upwind/Petrov–Galerkin (SUPG) and Pressure-Stabilizing/Petrov–Galerkin (PSPG) stabilizations in the ALE framework, mesh moving with Jacobian-based stiffening, and block-iterative FSI coupling. The turbulent-flow nature of the analysis is handled with a Reynolds-Averaged Navier–Stokes (RANS) model and SUPG/PSPG stabilization, supplemented with the “DRDJ” stabilization. As the structure moves, the fluid mechanics mesh moves with the Jacobian-based stiffening method, which reduces the deformation of the smaller elements placed near the solid surfaces. The FSI coupling between the blocks of the fully-discretized equation system representing the fluid mechanics, structural mechanics, and mesh moving equations is handled with the block-iterative coupling method. We present two-dimensional (2D) and three-dimensional (3D) computational FSI studies for an MA added to an axial-fan blade. The results from the 2D study are used in determining the spanwise length of the MA in the 3D study.

A Passively Morphing Trailing Edge Concept for Sailing Hydrofoil

Sailing sports are experiencing a period of radical innovations. Traditional displacing monohulls have always been the reference for yachting in the past, but the continuous quest for performances has generated many variations and many convergences with surprising results. On the aerodynamic side conventional soft sails have been sometime replaced by rigid wings, but the biggest innovation has been the use of traction kites as a propulsion device. On the hydrodynamic side we have seen the rapid growth of hydrofoils, an old concept that is having a rebirth. Probably the most remarkable expression of innovation and integration between concepts having different roots is the hydrofoil kite-board, point of encounter of the traditional wave surfing, the traction kite innovation and the hydrofoil technology. Hydrofoil kite-board can reach speeds up to 3 times the wind speed, are at least one order of magnitude cheaper than any boat with comparable performances, easy to manage and races are spectacular. Hydrofoil are object of investigation trying to further improve performances as well as to increase the stability and the “sailability". In the following we will present a concept that extends the range of efficiency of the foil through a completely passive morphing of the wing.