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In 2017, BMW unveiled this CFRP frame and swingarm for its HP4 Race motorcycle project. The swingarm was manufactured using resin-transfer molding (RTM). (BMW Motorrad)

Carbon fiber research eyes roof frames, doors

New 2020 SAE Technical papers detail current carbon-composite material developments.

It’s not just for exotic “supercars” and motorcycles anymore. The performance-enhancing attributes of carbon-fiber-reinforced plastics continue to be explored by global automakers as they seek high-volume solutions to vehicle lightweighting, particularly for the new wave of electric vehicles. SAE International’s Technical Papers library offers the latest insights into CFRP materials research, engineering, processing, and production technologies. The following papers were among many published in spring 2020.

Development of an Epoxy Carbon Fiber Reinforced Roof Frame Using the High Pressure Resin Transfer Molding (HP-RTM) Process
High-pressure resin transfer molding (HP-RTM) and related liquid compression molding (LCM) processes are enabling manufacturers to produce complex composite parts at increasingly reduced cycle times. This paper describes the development of an epoxy carbon fiber roof frame targeted for future vehicle production. Several composite processes were considered for the roof frame and the resulting carbon fiber frame met all OEM performance requirements and economic targets – while weighing 44% less than the original design in magnesium and 32% less on the overall assembly. The part was the first HP-RTM part successfully demonstrated in North America.

SAE Tech Paper no.: 2020-01-0773
Authors: Cedric A. Ball, Stephen Greydanus, Ian Swentek, Kameswara Rao Nara
Affiliation: Hexion Inc.

A Finite Element Design Study and Performance Evaluation of an Ultra-Lightweight Carbon Fiber Reinforced Thermoplastic Composites Vehicle Door Assembly
Closure systems account for ~ 50% of vehicle structural mass and have a very diverse range of requirements, including crash safety, durability, strength, fit, finish, NVH and weather sealing. To this end, an ultra-lightweight, carbon fiber-reinforced thermoplastic composite door being designed for an OEM’s midsize SUV enables 42.5% weight reduction. In this work, several novel composite door assembly designs were developed by using an integrated design, analysis and optimization approach. 

SAE Tech Paper no.: 2020-01-0203
Authors: Anmol Kothari, Aditya Yerra, Madhura Limaye, Sai Aditya Pradeep, Gaurav Dalal, Gang Li, et. al.
Affiliations: Honda R&D Americas, Clemson University, University of Delaware 

AFP Processing of Dry Fiber Carbon Materials (DFP) for Improved Rates and Reliability
Dry-fiber carbon materials have only been produced at relatively low rates or volumes for large aerospace structures. This paper explores the differences found when processing dry-fiber, thermoset, carbon materials (DFP) as compared to processing pre-preg, thermoset materials with Automated Fiber Placement (AFP) equipment at high rates. The heating systems, head controls and tow tension control all must be enhanced when transitioning to DFP processes.

SAE Tech Paper no.: 2020-01-0030
Authors: Michael Assadi and Tyler Field
Affiliation: Electroimpact Inc.

Investigation of Mechanical Behavior of Chopped Carbon Fiber Reinforced Sheet Molding Compound (SMC) Composites
As an alternative lightweight material, chopped carbon fiber reinforced Sheet Molding Compound (SMC) composites, formed by compression molding, provide a new material for automotive applications. This study investigates the monotonic and fatigue behavior of chopped carbon fiber reinforced SMC. The results suggest that the interfacial failure between fiber and matrix is the dominant damage mechanism for SMC under fatigue loading.

SAE Tech Paper no: 2020-01-1307
Authors: Xuze Sun, Carlos Engler-Pinto, Li Huang, et. al.
Affiliations: Ford Motor Company, Ford Motor Research & Eng. (Nanjing) Co.; Nanjing University of Aeronautics and Astronautics.

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