The Integrated Structural Assembly of Advanced Composites or ISAAC for short has been described as a milestone by NASA researchers and will change the way the organisation looks at composites.
Built by Electroimpact Inc., ISAAC is a modified version of a standard KUKA industrial robot. One of its key features is a large, rotating, disc-like head. The head is typically loaded with as many as 16 spools of carbon-fibre ribbon. The head isn’t a permanent fixture, however. It can be detached and replaced with identical ones loaded with different tools. As a result, transforming the system to work on a new job can be fast.
The idea to bring a composite-building robot to Langley grew from work by Chauncey Wu, a structural mechanics engineer at Langley who studied composites 20 years ago as part of his doctoral dissertation. Wu saw many advantages to tailoring, or steering, carbon fibres in custom patterns to make stronger aircraft or spacecraft bodies.
Manufacturers take carbon fibres smaller than human hairs and combine them with partially cured epoxy resins, to create narrow ribbons. These ribbons are the raw material used in many carbon-fibre composite materials. In ISAAC’s case, the ribbons are loaded onto the robot’s rotating head where they can be fused together in sheets according to precise patterns, directions or arrangements. Those sheets are layered, one on top of the other, and eventually fully cured into one solid, durable mass.
The new composites robot gives researchers more flexibility in arranging the ribbons and the fibres they contain. Conventional composites used in existing vehicles consist of many layers of fibres oriented at 0, 45 and 90 degrees. ISAAC can lay them down along a curving path, following a pattern designed to increase strength and performance.
ISAAC’s first assignments will be working for the Aeronautics Research Mission Directorate’s Advanced Composites Project and the Space Technology Mission Directorate’ Composites for Exploration Upper Stage. ISAAC may be also asked to build flight-quality hardware, scaled-down models of aircraft and spacecraft for research purposes, aeroelastically tailored structures for wind tunnel tests — even wind tunnel fan blades and helicopter rotor blades. The team is also looking at how the robot could be used to build metal parts or structures.
Image Credit: NASA/David C. Bowman