Manufacturing a 9-Meter Thermoplastic Composite Wind Turbine Blade

Abstract

Currently, wind turbine blades are manufactured from a combination of glass and/or carbon fiber composite materials with a thermoset resin such as epoxy, which requires energy-intensive and expensive heating processes to cure. Newly developed in-situ polymerizing thermoplastic resin systems for composite wind turbine blades polymerize at room temperature, eliminating the heating process and significantly reducing the blade manufacturing cycle time and embodied energy, which in turn reduces costs. Thermoplastic materials can also be thermally welded, eliminating the need for adhesive bonds between blade components and increasing the overall strength and reliability of the blades. As well, thermoplastic materials enable end-oflife blade recycling by reheating and decomposing the materials, which is a limitation of existing blade technology. This paper presents a manufacturing demonstration for a 9-m-long thermoplastic composite wind turbine blade. This blade was constructed in the Composites Manufacturing Education and Technology facility at the National Wind Technology Center at the National Renewable Energy Laboratory (NREL) using a vacuumassisted resin transfer molding process. Johns Manville fiberglass and an Arkema thermoplastic resin called Elium were used. Additional materials included Armacellrecycled polyethylene terephthalate foam from Creative Foam and low-cost carbonfiber pultruded spar caps (manufactured in collaboration with NREL, Oak Ridge National Laboratory, Huntsman, Strongwell, and Chomarat). This paper highlights the development of the thermoplastic resin formulations, including an additive designed to control the peak exothermic temperatures. Infusion and cure times of less than 3 hours are also demonstrated, highlighting the efficiency and energy savings associated with manufacturing thermoplastic composite blades.

IEA Wind TCP: Results of IEA Wind TCP Workshop on a Grand Vision for Wind Energy Technology

“…Although traditional thermoplastic resin systems have been evaluated in the past for use in wind turbine blade production, such drawbacks as very high temperature exotherm and elevated moisture sensitivity have prevented the adoption of thermoplastics in blade manufacturing. With the recent development of a two-part acrylic-based reactive thermoplastic resin system, including the successful demonstration of manufacturing a 9-m thermoplastic blade (Murray et al 2017), thermoplastic resins have been gaining interest as a replacement for thermosets in wind turbine blades because of their room temperature cure, recyclability (Cousins et al 2018), and decreased cycle times, which could lead to lower manufacturing costs (Bersee and Noi 2016;Murray et al 2018;Wiser and Bolinger 2016).…”

Mixed-Mode Interlaminar Fracture Toughness of Glass and Carbon Fibre Powder Epoxy Composites—For Design of Wind and Tidal Turbine Blades

“…Engineering thermoplastic matrices such as Nylon (PA) and Polybutylene terephthalate (PBT) could be considered for these large structures, but their viscosities are typically too high to achieve good consolidation under the vacuum-only processing conditions involved. Recent work in the use of low viscosity, in-situ polymerised thermoplastics such as acrylics have opened the field of manufacture of room-temperature infused large structures from thermoplastic composites [ 8 , 9 ], though there are still fundamental materials and manufacturing issues to be overcome.…”

Effect of temperature on damage mechanisms and mechanical behaviour of an acrylic-thermoplastic-matrix and glass-fibre-reinforced composite

“…Several projects are working on this, like the EFFIWIND project of which study forms a part. 15,16 Polymer composites have favourable properties such as low density, high stiffness and strength, high corrosion resistance and long fatigue lifetime. However, their thermomechanical properties are poor as their maximum service temperature is generally around 80-150 C. Thus, for instance, commonly used epoxy resins are limited to a maximum service temperature of about 120 C. 17 This maximum service temperature corresponds to the temperature at which the polymer becomes too soft and ductile as it approaches its T g , leading to a collapse of its mechanical properties.…”