Composite Dock
Building outdoor structures around water require special considerations. Wood rots, steel rusts, and dirt erodes. Fiberglass composites have been making strides in uses for marine-related activities. Round fiberglass pilings can replace wood pilings, and sheet pilings made of steel can be replaced with fiberglass retention walls.
The fiberglass composites have several advantages. They have a much longer service life because they do not rot or corrode. Compared to wood structures, they are more uniform in size. They are typically lower in weight to allow for lower lifting, handling, and transportation load requirements.
All of these advantages are used by a company called Green Heron Docks that builds docks in a “green” manner. Their docks are build from the previous dock sections, allowing for minimal interruption of the surrounding environment. Their installed docks will have a long life that will not require replacement related disturbance for time to come.
Their video on Youtube
As you can see, their equipment is relatively lightweight and inexpensive compared to bringing in cranes and barges. Their environmental impact is minimal, and the resulting product has a very long service life that will endure for years to come.
Environmentally Friendly Composites
Many experts argue that composites already are very environmentally friendly based upon their long life span and their good strength-to-weight ratio that saves energy. Many composites structures have long made use of end-grain balsa wood as a core material. This is a renewable resource that is favorable to the carbon footprint.
The strikes against fiberglass composites as being environmentally friendly point out that most of the resin systems are derived from oil and natural gas feedstocks. Most of these feedstocks come from the extra byproducts of making diesel and gasoline. Fiberglass reinforcements consume lots of energy in their manufacturing process.
Resin and reinforcement companies have been working to “green” composites materials. BioResins have been successfully made and used in products that see the real world. These resins use soybean and corn feedstocks to replace the oil and natural gas derivatives to make them from a renewable source. Much work has been accomplished with reinforcements to move towards natural materials. Hemp has proven very useful in this application. Recycled thermoplastics have also been applied to composites products as a reinforcement.
Further research and development, along with identifying appropriate real-world applications will allow composites to flourish as a true sustainable material. It has already proven to be a great material for lightweighting vehicles and structures to result in great energy and material savings. The long life and durability of composites keeps it from landfills to minimize environmental impact.
Composites Application: Utility Trucks
A composites materials application I recently looked at was a man-lift bucket made from composites. These man-lift buckets are mounted on a lifting arm atop a work truck to lift workmen up to perform utilities repairs and service. This is an application that has been around for a long time, and is a great fit for composites materials.
Utility bucket lays sideways for travel
These buckets are designed to hold one or two people and allow them to perform jobs such as hanging electrical wires, television cable, and telephone lines. The workers also need to work on the utility poles and trim the trees and vegetation growing near the lines.
This is a great composites application for serveral reasons.
*The composites allow the manlift bucket to be non-conductive for safety reasons. Many other considerations are made to prevent electricution, and this adds to those safety considerations.
*The bucket is also lightweight due to composites, which allow for greater lifting capacity of the workers and their tools because weight is not used inthe lifting device itself.
*These trucks spend the majority of their lives outdoors, and the anti-corrosive nature of composites helps give these manlift buckets long lives.
Fiberglass composites are normally non-conductive, and this is a very important consideration for applications such as these involved with utilities. Composites are found in many applications where electrocution is possible.
Not all composites materials are non-conductive, however. The use of conductive fillers and reinforcements can allow for electricity to travel in these applications. Carbon fiber and carbon black are a couple of ingredients that can cause this. Testing finished composites for conductivitiy can be conducted to determine their insulative properties.
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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