As the sizes of offshore wind turbines increase, operators are finding it challenging to transport, install, disassemble, and dispose the gigantic rotor blades of these turbines. In partnership with other industry experts, Fraunhofer researchers are working towards developing highly durable thermoplastic composites and foams that will help in building lighter and recyclable blades.
The special properties of the new materials also help to construct other lightweight structures in domains like the automotive sector. The introductory demonstrators will be kept for display at the K 2016 trade fair in Düsseldorf from 19th – 26th October, 2016.
The trend towards large offshore wind farms is relentless. Wind turbines with rotor blades that measure up to 80 m in length and a rotor diameter of more than 160 m are designed so that maximum energy yields can be attained. As the length of the blades is restricted based on their weight, it is essential for lightweight systems that also possess high material strength to be developed.
If wind turbines are lower in weight they will have enhanced stability at sea, and would be easily assembled and disassembled. As part of EU’s Wind Blade Using Cost-Effective Advanced Lightweight Design (WALiD) project, scientists at the Fraunhofer Institute for Chemical Technology ICT in Pfinztal are working together with almost 10 industry and research partners to come up with a lightweight design of rotor blades. These scientists intend to reduce the weight of the blades and also to increase its service life by improving the design and the materials used.
Thermoplastics are Replacing Thermoset-Based Materials
Wind turbines are often made by hand thermosetting resin systems. However, these do not allow melting, and are not suitable for material recycling. The best property of granulated thermoset plastic waste is that, they can be recycled and used as fillers in simple applications.
Scientists aim to separate the glass and carbon fibers and reuse the thermoplastic matrix material.
The project partners used sandwich materials that are made up of fiber-reinforced plastics and thermoplastic foams to build the outer shell of the rotor blade and also for the segments of the inner supporting structure. Generally, carbon-fiber-reinforced thermoplastics are used in places where very high loads are applied in the rotor blade, and glass fibers are used to reinforce the less stressed areas.
Rapp and his team of scientists are now developing thermoplastic foams that are bonded with cover layers made of fiber-reinforced thermoplastics in sandwich design for the sandwich core. This combination enhances the durability, efficiency, mechanical strength and longevity of the rotor blade. “We’re breaking new ground with our thermoplastic foams,” says Rapp.
To read the full story, visit http://www.azom.com/news.aspx?newsID=46558.