I-Corps: Manufacturing of seamless and structurally differentiated carbon-fiber reinforced composite materials

Regents Of The University Of Michigan - Ann Arbor, Ann Arbor MI

Investigators

Abstract

This I-Corps project focuses on a new method of production of light-weight carbon fiber materials. Industries such as aero-space and automotive manufacturing require light weight replacements for steel components to reduce vehicle weight and increase fuel efficiency. While carbon-fiber reinforced composites are pursued as a material-technology to replace metal parts, the current cost of manufacturing those composites restricts wide adoption. Carbon-fiber reinforced composites are largely made with woven or unidirectional carbon fiber mats. The planar nature of these sheets introduces inefficiencies in the production of complex 3-dimensional parts. Expensive tooling is required to stamp the sheets into the desired non-planar shape. For complex 3D formwork, extensive person hours are needed to individually wrap each sheet around the formwork. This team developed a new method of design and manufacture of composite materials, enabling a range of integrated properties within a single seamless material. Computer numerically controlled (CNC) knitting technology is used to allow for the automated manufacturing of complex shaped 3D textiles without the need for manual post-production in cutting or sewing multiple pieces. The textiles are used as the reinforcement in the production of high performance lightweight composite materials. Through the production of knitted preforms with 3-D shaping, tailoring of fiber orientation and density, and integration of varying yarn types, a composite part can be developed with a range of structural properties. This team's methodology enables knitting with carbon fiber in various hybrid yarn compositions to overcome the brittle nature of carbon fiber and its tendency for breakage during the knitting process. This allows for the production of composite parts which embed a range of structural properties, meaning multiple components can be synthesized in a single part, reducing the number of overall parts in an assembly. Integrating capabilities for 3D knitting, the "net-shape" or final desired shape of the composite part can be accomplished with a single seamless pre-form. By designing parts to a net shape, the process minimizes time in the lay-up of the pre-form and reduce waste in the manufacturing process. The initial target for this technology is automotive manufacturing -- to reduce the weight and number of components for various assemblies within the automobile. Currently, carbon fiber composites are being used in some automotive manufacturing, but most often with low-production vehicles. This significantly limits adoption as composite manufacturing is more expensive in material costs and slow in the cycle times for manufacturing. Thinking in terms of synthesizing multiple parts and reducing the number of parts/steps for manufacturing of a whole assembly, such as the door, would reduce the increased cost by weight saved, to more acceptable standards. Such an approach can be valuable to other industries such as aerospace, sporting goods, furniture, medical devices, and a broad range of other applications.