A seat that provides good vibration isolation is of prime importance for passenger’s safety and health. The main conflict in seat suspensions implies that the increasing initial deformation of the system (increase in “static discomfort”) leads to better isolation of accelerations (increase in “dynamic comfort”). Many researchers have focused on overcoming or at least suppressing this conflict between load support capacity and vibration isolation by modeling new suspension systems, such as the so-called negative suspension systems. However, apart from the modeling of new suspension systems, optimization is an important part in designing a seat and finding the best compromise between these two objectives. Thus, in this work, four types of seat suspension systems with embedded negative stiffness elements are implemented and optimized in order to be benchmarked. Three of them have already been tested either in passenger or in an off-road vehicle seat. All the vibration isolators are optimized with genetic algorithms in respect to static and dynamic factors of ride comfort by applying constraints oriented to the objectives and the design of the structure. The optimization is implemented for two excitations, which correspond to a vehicle driving over road profiles of Classes A and B, and the common solutions are outlined.

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An EERA (European Energy Research Alliance) consortium started an ambitious EU FP7 project AVATAR (AdVanced Aerodynamic Tools of lArge Rotors) in November 2013. The project lasts 4 years and is carried out in a consortium with 11 research institutes and two industry partners. The motivation for the AVATAR project lies in the fact that future 10 to 20 MW turbine design model analysis will importantly violate known validity limits of today's aerodynamic and aero-elastic models in aspects like compressibility and Reynolds number effects, laminar/turbulent transition and separation effects, all in combination with a much more complex fluid-structure interaction. Further complications enter by the possible use of active or passive flow devices. AVATAR's main aim is then to develop enhancements for aerodynamic and aero-elastic models suitable for large (10MW+) wind turbines analysis. The turbine modelling improvements will be demonstrated on a new 10MW reference turbine design model description. The first results from the AVATAR project are presented in this paper.