Tuesday, March 30, 2010

Wind Turbine Interference on Radar

Wind farm development has seen resistance from a variety of people/groups. Some environmentalists fear the safety of bats and birds caught in the path of the blades. Local residents of potential developments fear blocked views, noise, and even flickering of shadows.

Another concern, is the disruption wind turbines can have on radar. Here is a recent ABC News article discussing the Pentagon's concern that wind farms may disrupt radar systems, and could be a homeland security threat.

If wind turbines stood still, there would be no problem. Modern radar is programed to ignore stationary objects. However, with tip speeds over 200 mph, large wind turbines create a signature that can be reported on radar. Above is an image from the NOAA, the star represents a Doppler radar tower, and the circled area is the disruption from a local wind farm. Looks like a thunder storm is moving in right? According to the NOAA:
"The rotating turbines also impact the velocity base data as you can see from the below image.  This velocity data is used by radar operators and by a variety of algorithms in the radar's data processors to detect certain storm characteristics such as mesocyclones, tornado vortex signatures, and relative storm motion."
With the National Weather Service, there is a concern as a severe weather event such as a flash flood could roll through undetected as it is passed off as wind turbine interference. Here are a couple more interesting images.

Photo Credits: NOAA National Weather Forecast Office Buffalo, NY

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Monday, March 29, 2010

Composites vs Metal

Above is a helpful material property comparison of composites and metals. Below is an interesting graph comparing the fatigue strength of composites vs metal. Enjoy...

Source: Advanced Composite Materials Technology Research Centre at The Hong Kong University of Science and Technology.

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Wednesday, March 24, 2010

Life Cycle Assessment

We have talked before about life cycle assessment (LCA) of products manufactured with composite materials. Here is a paper discussing the life cycle of a surfboard. A surfboard is more or less a composite sandwich structure. The core is either a polyurethane foam core or eps foam core. A wood stringer is added down the center for stiffness. The skins are generally woven 4oz fiberglass, often 2 layers on top and one on the bottom. Resin is epoxy or more commonly polyester.

In the life cycle analysis paper, the author cites more carbon emissions are created driving to and from the beach then the life of the surfboard will ever produce. Recently, companies have been experimenting with greener surfboard materials. In particular, bio-based resins, fabric, and foam. However, at least from a greenhouse emissions point of view, the composite construction of the board is a moot point in comparison to the emissions surfers generate driving to the beach.

I imagine similar studies for other products manufactured with composite materials will find similar statistics. It also exemplifies that we need greener transportation, and composites will play a role in reducing automotive weight and increasing fuel efficiency.

Photo Credit: Hot Tamale Surfboards

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Monday, March 22, 2010

DARPA Composite Armor Development

Some great warfighter technologies come out of the DARPA. Here is a synopsis for the development of composite armor with private company Hardwire.
"In collaboration with the U.S. Army, the Hardwire® DARPA Armor program exploited unique hybrid composite materials in innovative geometries and systems to provide improved military vehicle armor protection at a significantly reduced weight compared to other technologies. This approach to armor design has provided a suite of armor solutions that can be tailored to meet mission and vehicle-specific weight and performance requirements in response to specific and emerging threats. New insights and infrastructure for armor manufacturing has changed hybrid, composite armor production from a labor-intensive, small-quantity process to a quality-controlled, high-throughput operation. The program applied automated high-precision production fabrication technologies to adaptively and rapidly produce panels to specification and at a cost comparable to that of traditional armor. These changes in the composite armor design and production paradigm have made life-saving armor systems available for warfighter vehicles"
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Thursday, March 18, 2010

Recycled Plastic as a Building Material

There are a few building materials already using recycled plastic; some composite decking products use recycled polyethylene grocery bags. The video above describes a whole new building product. Here, it appears the variety of ground up plastics are held together by a thermoset. If this is the case, the plastic will act as the reinforcement in the new composite material...

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Wednesday, March 17, 2010

Bio Medical Composite Materials


Composites will continue to gain acceptance in the biomedical field. When compared to metals (titanium, nickle, stainless, etc) used in bio medical, composite materials have some distinct advantages. Composites are x-ray transparent allowing doctors to take less x-rays to better see injuries and how they are healing. Many patients have allergies to nickle and other alloys, which limit the bio medical components that can be used. Above is a paper going into further detail on the subject, and is worth the read.

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Friday, March 12, 2010

Shape Memory Composite

Photo Credit: Technology Review

Imagine an airplane wing that could change shape when it hits a certain speed and become more aerodynamic. Perhaps one day this will become a reality. Technology Review reports on some polymers that have multiple shape memories. Meaning, when the polymer reachers a certain temperature, it will change into a preset shape...

Pretty awesome if you ask me.

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Thursday, March 11, 2010

Airplane Bomb Protection: Composite Materials

Photo Credit: Dave Sizer via flicker

The recent Christmas day "Underwear Bomber" failed, but what if he was successful? The folks at the Discovery Channel and the BBC put this to the test, setting off a similar explosive in a retired airframe. (You can watch the preview here.)

Not only would the airframe survive, but it is thought that a next-generation aircraft built with composite materials such as the 787 Dreamliner would do better:
"The BBC also used a decommissioned Boeing 747 and not a newer Airbus A330 for the test. An actual test would be necessary to prove this, but Wyatt and Joseph think that the newer plane, which was made with lighter and stronger composite materials instead of aluminum, would have performed even better.
The newest commercial passenger jet, the Boeing 747 or Dreamliner, which has even more composite materials, would likely perform even better, said Wyatt, although he doesn't know for sure."
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Tuesday, March 9, 2010

Recycling Composite Materials

For many reasons, composite material products need to have a better solution for their end of life. Thermoset composites have difficulties in reprocessing, however thermoplastic composites are showing some promise. Technology Review discusses some breakthroughs in recycling PET, which may provide some foundation for recycling fiber reinforced PET in the future. Essentially, researchers at IBM have figured out how to chemically break down PET to their original parts, which then can be used again. Traditional recycling of PET uses heat and pressure to melt down the plastic.

Although recycling composite materials is necessary, composites still provide valuable environmental savings during their life. In composite transportation products such as marine, rail, aerospace, and automotive, the fuel saving and carbon reduction benefits can outweigh the downside of not being able to recycle. Here is a Swedish study of a Life Cycle Analysis (LCA for short, and likely an acronym we hear often) of fiber reinforced composites.

In the study, the researched compared the LCA of a steel ship with composite sandwich structures. Even though steel is recycled in the end, the emission reductions and corrosion benefits of using composite materials outweigh the recycling benefit.

Now, imagine the LCA comparison when fully recyclable composites are used...

Photo Credit: jsbarrie via flicker

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Monday, March 8, 2010

International Defense Use of Composite Material

Obviously the US Department of Defense is one of the largest customers and users of composite materials, however, as technology advancements and military budgets expand in countries such as China and India, so will the demand for composite materials.

Above is a video describing how the large multi-national company ThyssenKrupp is integrating advanced composite materials into the Indian Navy.

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Monday, March 1, 2010

End of Life Solution for Plastics and Polymers

Above is a short documentary about a trip to the great pacific garbage patch, a three part series following a voyage to a collection of plastic larger then the state of Texas. The film should create serious questions for anyone involved in the composites, plastics, or polymer industries.

If one thinks about it, we come into contact with plastics constantly on a daily basis, from our toothbrush in the morning, to the synthetic bed we sleep on at night. This dependence is only going to continue. Even our electricity will be created from FRP wind blades and our cars will be manufactured from lightweight polymer composites.

Yet, the composites industry has no end solution for our products. Currently, traditional FRP products goto landfills or incinerators at the end of life. This is unacceptable, and more importantly, unsustainable. The composite industry as a whole needs to continue the search for better materials and further develop a realistic and functional solution for end of life solutions.

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