Design and Optimization of Composite Base Frames and Shaft of Wind Turbine for Catamaran

Abstract

The development of renewable energy though science is a major challenge for the future. While the fossil resources are diminishing, the worldwide energy demand continues to increase. Today, the most of the industrialized countries primarily use energy from nuclear power because of the fact that it is very economical. Though, the nuclear energy produces some radioactive waste which is hazardous for human and nature. Transition of the energy is one of the biggest challenge of the 21st century in order to keep the environment cleaner. In this perspective, the team of Energy Observer has embarked on a project which is to design and construct of a floating laboratory called “Energy Observer” catamaran.

The catamaran is fully working with electrical energy from renewal energy sources which are powered by self-generated hydrogen, sun and wind. The previous name of the boat was “Formule Tag” which won the race called Jules Verne in 75 days at 1994, and this boat was converted in a shipyard at Saint Malo which is on the North West coast of France. In order to use the solar energy, the boat is equipped with 130 m2 of solar panels and to use the wind power, two vertical axis wind turbine will be installed. These wind turbines are able to create energy regardless of the wind direction. The main purpose of Energy Observer is to explore the oceans without leaving any exhaust gas to the environment. The aim is to make a world tour for a period of six years with only using the renewable energy, without any carbon-emitting fossil fuels.

The main objective of this study is to design the shaft of a vertical axis wind turbine as well as its support using composite material. Optimization of the laminates as well as static and dynamic structural analyses of the overall structure are carried out by use of Finite Elements Method. Furthermore, regarding the vibrating behaviour of the wind turbine, avoiding the resonance problem in specified working range of the wind turbine is another task to be solved. For this purpose, some modifications are done such as changing the material thickness, increasing the number of composite layers, designing an additional interior steel frame, changing the shape of structures. The effects of these modifications on the whole structure is investigated. Moreover, in order to reduce the transmission of vibrations from wind turbine to the catamaran itself, a composition of viscoelastic material and carbon is considered, tested in the vibration laboratory of ICAM Nantes campus and numerically modelled.