A Filament Winding Concept to Improve the Strength and Stiffness Characteristics of Thermoplastic Large Injection Molded Composite Automotive Body Panels

The automobile industry is seeing an increased need for the application of plastics and their derivatives in various forms such as fiber reinforced plastics, in the design and manufacture of various automotive structural components, to reduce weight, cost and improve fuel efficiency. A lot of effort is being directed at the development of structural plastics, to meet specific automotive requirements such as stiffness, safety, strength, durability and environmental standards and recyclability.

This paper presents the concept of reinforcing large injection molded fiber reinforced body panels with structural uni-directional fibers (carbon, graphite, kevlar or fiber glass) wound in tension around the body panels by filament winding technique. Structural uni-directional fibers in tension wound around the fiber reinforced plastic inner body panels would place these body panels under compression. This compressive load on the inner body panels, along with the actual load on the uni-directional fibers in tension contribute to a structural plastic that would be several times much stiffer and stronger than the injection molded plastic body, similar to pre-stressed concrete (especially at high temperature). The paper also highlights the use of thermoplastic coated fiber bundles as a new approach to this application, which is a cleaner manufacturing process compared to the more traditional wet resin filament wound process.