Carbon Fiber Yike Bike
People are coming up with a lot of great products made of carbon fiber composites. The nature of these products makes the use of composites a requirement.
I found an interesting video of a very specialized carbon fiber bike. Called the Yike Bike, it is basically an electric scooter that allows for urban transportation. The bike folds into a small and portable unit that can be easily carried and stored.
The use of carbon fiber is necessary due to the requirements of light weight and high strength. It is necessary for this scooter to support and transport people of various size and weight. The bike also must be lightweight so that it can be easily carried aboard trains and into office and apartment buildings.
This unit is definitely a feat of engineering, and is available to the public in the Summer of 2010. It is pricey, but fills a unique role for those that require urban transportation.
Non-Destructive Testing with Ultrasound
Composite materials can become damaged in many different ways. There can also be flaws in the original manufacturing process. Many times it is necessary to identify any damaged areas within the composites layers that cannot be detected with the eye.
Inspection of composites fiberglass and carbon fiber structures may be required for advanced critical applications of composites materials. Identifying any potential problems with the composites structure is extremely important.
Of course problems can be identified through destructive testing-drilling holes, making cuts, etc. It also may be necessary to do testing in a non-destructive manner, i.e. not cutting into the laminate that is being tested.
One method of accomplishing non-destructive testing of composites laminates is using ultrasound. This Youtube video demonstrates the use of this method.
As you can see, the damage is found in this carbon fiber laminate. This information is a flag that can be used to decide whether to make a repair or replace the structure.
Delamination within the fiberglass or carbon fiber part will result in a much weaker structure than the design intended. Other areas of the composites part will be further strained by weaknesses in other areas and may also fail.
This ultrasonic test can help to identify otherwise invisible problems with either the original manufacturing process or damage during the life cycle of the composite part.
Cirrus Composite Airframes
I found a very interesting Youtube peek inside of the Cirrus airplane assembly factory in Minnesota. While it would be cool to learn more about the actual composites fabrication of the individual parts, there is some great information about part bonding, inspection, and final assembly of the Cirrus aircraft. They use fiberglass and carbon fiber reinforcements to create a very strong and durable fuselage, and it is great to see in action.
Personal jets made of composite materials offer many advantages and unique properties. Design of complex shapes and anti corrosion of aluminum are two advantages. Disadvantages include repeatability and upgrading/modification.
Composites that are properly designed and fabricated can be used in many applications where safety is a big concern. Proper design and inspection during production can create an airplane that can be easily maintained and have a very long life.
Great factory tour courtesy of Aero-TV:
NASA Composite Crew Module
NASA, the space agency for the U.S. government, has investigated the use of advanced composites for use in future vehicle programs. The Composite Crew Module (CCM) has been designed and built as a travel vehicle for astronauts in future space programs to travel. Drawing parallels to the Apollo program, this module will be launched on a rocket and break away as a module.
This technology and material are undergoing testing and evaluation before it is officially accepted for the Orion program. As a partnership between government agencies and public companies, this technology aims to reduce weight and improve performance of the manned vehicles.
From NASA’s website “Led by the NESC, the project team is a partnership between NASA and industry, including design, manufacturing, and tooling expertise. Partners are civil servants from nine NASA Centers – ARC, DFRC, GRC, GSFC, JSC, JPL, KSC, LaRC, and MSFC; the Air Force Research Laboratories; and contractors from Alcore, Alliant Techsystems, Bally Ribbon Mills, Collier Corporation, Genesis Engineering, Janicki Industries, Lockheed Martin, and Northrop Grumman. The CCM team operates in a virtual environment, electronically connecting participants across the country.”
This full-scale structure has strain gauges attached to monitor loads on the structure. It was announced on January 25 that it has passed a battery of stress tests to prove viability.
The structure appears to be made with carbon fiber materials, maybe with some graphite reinforcement and an epoxy resin system. Mention of aluminum honeycomb can be found in the online reading materials. The main pieces are autoclaved, while bonding of the large sections (upper and lower shells) is accomplished outside of the autoclave.
Composites technology is being developed for future space exploration structures and vehicles, and this is good news for the composites industry!
Carbon Fiber in the Chevrolet Silverado ZR2 Concept
At the 2009 Las Vegas SEMA show, Chevrolet introduced their ZR2 Concept pickup truck. This truck is tricked out for off-road capability with all wheel drive and a tricked out suspension. Weight savings improves performance and the designers turned to carbon fiber composites.
Exterior body panels were improved by saving weight by using carbon fiber. These panels include the hood, fenders, tailgate, grille, fascias, fender flares, and rocker panels. The hood and tailgate have used clear-coated carbon fiber to show the weave and give an interesting two-tone look to the vehicle.
The interior is also reported to use carbon fiber in the dash and the door panels.
It is unknown whether this concept vehicle goes into production, but certain elements are certainly becoming mainstream. Aftermarket carbon fiber parts have been popular for years especially on tuner cars. This may catch on for mainstream OEM production. Carbon fiber parts save weight, do not corrode, do not dent, and do not require pigmented paint.
Boeing’s 787
Boeing’s 787 will be the first composites-intensive commercial airliner. Traditionally made from aluminum, carbon fiber composites will work to create a plane that is stronger and lighter with fewer manufactured parts. Carbon Fiber reinforcement with Epoxy resin will be the main construction of these composites, which will make use of an autoclave during processing to control the molding conditions and ensure the quality and durability of the laminate.
Composites will reduce the number of parts for the airplane, and Boeing predicts that the front section alone would normally require using 1,500 sheets of aluminum, which also means drilling between 40,000 and 50,000 holes for the nuts and bolts to attach these sheets together and to the underlying framework. Carbon Fiber composites will allow for the skin and underlying supports to be molded as one large piece. Boeing predicts that assembly line time will be reduced from about three weeks to attach all of this aluminum together to about 3 days to attach the large composites sections together for the entire plane fuselage.
Switching materials has its’ own set of problems to overcome. The customers’ mechanics will need to be trained to repair damage on these composite planes. Damage detection will be important as well. Some will be visible to the naked eye, and other damage will not. Several forms of Non Destructive Testing will be employed to test for damage and wear on the composites body to ensure a safe aircraft.
Composites have been used in aircraft before, but not as extensively in commercial airplane bodies. Existing commercial airplanes have made use of composites in other areas to help make the planes stronger and lighter. Military jets have used carbon fiber composites for many years in their technologies for strength and weight advantages. Private business jets have utilized fiberglass composites for many years in their construction. Homemade kit planes have also made extensive use of fiberglass to make inexpensive craft in personal shops.
The profile of carbon fiber composites will definitely be elevated if Boeing’s 787 becomes as successful as promised.
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