Sandwich Materials for Wind Turbine Blades — Present and Future

Abstract

Wind turbine blades are being manufactured using polymer matrix composite materials, in a combination of monolithic (single skin) and sandwich composites. Present day designs are mainly based on glass fiber-reinforced composites (GFRP), but for very large blades carbon fiber-reinforced composites are being used increasingly, in addition to GFRP by several manufacturers to reduce the weight. The size of wind turbines have increased significantly over the last 25 years, and this trend is expected to continue in the future. Thus, it is anticipated that wind turbines with a rated power output in the range of 8—10 MW and a rotor diameter about 170—180 m will be developed and installed within the next 10—15 years. The article presents an overview of current day design principles and materials technology applied for wind turbine blades, and it highlights the limitations and important design issues to be addressed for up-scaling of wind turbine blades from the current maximum length in excess of 61 m to blade lengths in the vicinity of 90 m as envisaged for future very large wind turbines. In particular, the article discusses the potential advantages and challenges of applying sandwich type construction to a larger extent than is currently being practiced for the load-carrying parts of wind turbine blades.