{"id":15075,"date":"2020-01-16T09:09:54","date_gmt":"2020-01-16T09:09:54","guid":{"rendered":"https:\/\/www.compositestoday.com\/?p=15075"},"modified":"2020-01-16T09:09:54","modified_gmt":"2020-01-16T09:09:54","slug":"mit-new-composites-method-no-autoclave","status":"publish","type":"post","link":"https:\/\/www.compositestoday.com\/2020\/01\/mit-new-composites-method-no-autoclave\/","title":{"rendered":"Researchers Create New Method of Producing Composites Without the Heavy Machinery"},"content":{"rendered":"

A modern aeroplane\u2019s fuselage is made from multiple sheets of different composite materials, like so many layers in a phyllo-dough pastry. Once these layers are stacked and moulded into the shape of a fuselage, the structures are wheeled into warehouse-sized ovens and autoclaves, where the layers fuse together to form a resilient, aerodynamic shell.<\/p>\n

Now MIT<\/a> engineers have developed a method to produce aerospace-grade composites without the enormous ovens and pressure vessels. The technique may help to speed up the manufacturing of aeroplanes and other large, high-performance composite structures, such as blades for wind turbines.<\/p>\n

The researchers detail their new method in a paper published in the journal Advanced Materials Interfaces.<\/p>\n

If you\u2019re making a primary structure like a fuselage or wing, you need to build a pressure vessel, or autoclave, the size of a two- or three-story building, which itself requires time and money to pressurize. These things are massive pieces of infrastructure. Now we can make primary structure materials without autoclave pressure, so we can get rid of all that infrastructure. Brian Wardle, professor of aeronautics and astronautics at MIT<\/cite><\/p><\/blockquote>\n

Wardle\u2019s co-authors on the paper are lead author and MIT postdoc Jeonyoon Lee, and Seth Kessler of Metis Design Corporation, an aerospace structural health monitoring company based in Boston.<\/p>\n

Out of the oven, into a blanket<\/h3>\n

In 2015, Lee led the team, along with another member of Wardle\u2019s lab, in creating a method to make aerospace-grade composites without requiring an oven to fuse the materials together. Instead of placing layers of material inside an oven to cure, the researchers essentially wrapped them in an ultrathin film of carbon nanotubes<\/a> (CNTs). When they applied an electric current to the film, the CNTs, like a nanoscale electric blanket, quickly generated heat, causing the materials within to cure and fuse together.<\/p>\n

With this out-of-oven, or OoO, technique, the team was able to produce composites as strong as the materials made in conventional aeroplane manufacturing ovens, using only 1 per cent of the energy.<\/p>\n

The researchers next looked for ways to make high-performance composites without the use of large, high-pressure autoclaves \u2014 building-sized vessels that generate high enough pressures to press materials together, squeezing out any voids, or air pockets, at their interface.<\/p>\n

Researchers including Wardle\u2019s group have explored \u201cout-of-autoclave,\u201d or OoA, techniques to manufacture composites without using the huge machines. But most of these techniques have produced composites where nearly 1 per cent of the material contains voids, which can compromise a material\u2019s strength and lifetime. In comparison, aerospace-grade composites made in autoclaves are of such high quality that any voids they contain are negligible and not easily measured.<\/p>\n

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