A Systems Approach in Developing a Ultralightweight Outside Mounted Rearview Mirror Using Discontinuous Fiber Reinforced Thermoplastics
To be published on April 2, 2019 by SAE International in United States
Fuel efficiency improvement of automobiles has been a topic of great interest in the past years, especially with the introduction of new CAFE standards. Although there are multiple ways of improving the fuel efficiency of an automobile, light weighting is one of the most common approaches taken by many automotive manufacturers. Importance of lightweighting is more significant in electric vehicles as it directly effects the range. The use of composite materials in place of metals has proven to achieve substantial weight reductions in the past. The focus of using these composite materials for weight reduction was generally limited to major structural components such as BiW and closures, due to the high material cost. Secondary structural components which contribute approximately 30% of the vehicle weight are usually neglected by these weight reduction studies. This work is an attempt to prove that composites can also be used effectively in the weight reduction of secondary structural components while meeting the mechanical performance, cost and scalability. Discontinuous fiber reinforced injection molded materials offer good mechanical properties and very high lightweighting potential. In this paper, a secondary structural component such as outside mounted rearview mirror assembly is used to study the effect of performance and cost while trying to achieve a mass reduction of at least 30%. An injection molded long carbon fiber reinforced nylon is used to replace the aluminum structure in the baseline mirror assembly. In addition to material replacement, a 20%-parts consolidation was achieved due to the design freedom offered by these materials. A virtual plant layout was developed to determine the cost of series manufacturing. In conclusion, this paper provides a strong case for the use of these material systems to lightweight small & secondary structural components.