Bayer conducted tests to compare the properties of epoxy and vinyl ester resin systems with a polyurethane resin system. Two sets of long-flow vacuum infusion experiments were designed to compare the flow rates of the two different resins. The research team also studied the effects on the properties of fiber-reinforced composites by including multi-walled carbon nanotubes.
The team found that the nanotubes helped improve the fracture toughness of the composites. "Incorporation of a small amount of multi-walled carbon nanotubes improves the fracture [toughness] of both polyurethane and epoxy composites by as much as 48 percent," Younes said in a second press release. "The addition of carbon nanotubes is a viable option to improve the strength of wind turbine blades."
The tests were part of a recent study funded in part by a Department of Energy grant for the development of stronger composite materials for wind blades. The grant also helped fund development of the Baydur polyurethane system and will fund additional research comparing the performance of new polyurethane resin systems with those of traditional epoxy and vinyl ester resins used for wind blades.
Bayer has also developed the Baydur Resin Transfer Molding (RTM) custom polyurethane system for making wind turbine root rings and blades, as well as lightweight structural components for the transportation industry. The custom formulation improves process efficiency by offering a faster demold time than epoxy. The wall thickness of parts can be decreased, yet the material is stronger than polyester, resulting in lighter parts that maintain strength.
Seems like the Bayer MaterialScience technology has a lot of promise in terms of promoting wind turbine blade design. Along with materials, simulation software is also playing a huge role in perfecting wind turbine blade design and for pushing for much bigger, higher capacity blades. Click here to read about Sandia National Labs' research project effort to build a 100m blade, which in a traditional three-bladed turbine design, would take up a footprint of about two-and-a-half football fields in size. The massive blade is aimed at off-shore turbines.
Thanks Beth for weighing in about the simulation software used for wind turbine blade design. I would think that designing blades, root rings and other components of wind turbines must be quite a challenge, especially in alternative materials. It only makes sense that software is part of the design engineer's toolkit for making bigger blades possible.
Absolutely Ann, there issues around aerodynamics and airflow as well as structural integrity and reduction in weight--all key factors that can be explored and optimzed in the virtural world with FEA, CFD, and other CAE software. With simulation, designers of these wind turbine blades can test out many more design options virtually, prior to investing the money to build physical prototypes, which is a huge expense, especially with the growing size of these blades and with all the new composite materials, which are costly.
Sounds like the ability to design blades and other components using composites is probably highly dependent on that simulation ability. No doubt this is also a major contributing factor to why there's a big increase in the use of composites in so many apps, not just the fact that there are so many more versions of composite materials to choose from. Thanks for the info.
Nice article, Ann. Turbines keep getting more efficient and more effective. Another area of research is going to create turbine blades that are optimized to gain the most of the wind. The blades are controlled to change position as the wind direction and velocity changes, the goal being to get the most efficient use of the wind at all times.
Thanks for the input. Rob. I know you've written about alternative energy sources like wind turbines, which are relatively new to me. Making them larger makes sense, but solving the weight-to-size ratio problem sounds pretty major. I bet the CAE software has made a big difference there. And I bet it's also key in figuring out how to design the blades that optimize wind, as you describe.
So far the tools to control the blades for optimum turn is still on the drawing table. Yet I can certainly see the need for it after driving by so many turbines that are sitting idle just because the wind isn't blowing in the right direction. I would imagine we'll see a ton of development in wind in the coming years.
Oh, I get it. I didn't realize you meant not only getting the most out of a particular gust of wind, but keeping them going in the first place, so they are turning whenever there's wind instead of staying idle just because there's wind but not going the right way.
Blade control is one of the areas where potential technology developments could improve the efficiency of wind turbines. Today, most turbines are using independent pitch control where each blade is independently controlled by a servo actuator. But all of the blades respond to the same command as they go through their cycle. Individual pitch blade control provides real-time feedback from blades or monitoring devices, and one approach is to embed sensors into the blades for real time load feedback. The system closes the loop at the turbine level using that feedback to significantly reduce the load variation from blade to blade. The result is an ability to handle peak gusts better and more quickly.
I would also expect that reducing the weight of the blades could help boost overall performance. With the emphasis on offshore installations and much larger turbines, the weight of the blades is a huge factor for design, installation and maintenance.
Advantech has launched a new series of motion-control I/O modules to meet the increased demands that come with more distributed industrial systems that require control of a growing number of axes and devices.
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