Sustainable Lightweight Intelligent Composites (SLIC) for Next-Generation Vehicles

Driven by zero carbon emission goals, lightweight highstrength carbon fiberreinforced polymer CFRP composites have emerged as the nextgeneration structural materials for automotive vehicles. However, their widespread adoption by the automotive industry is hindered by two significant obstacles: the high cost of carbon fibers and reliability concerns coupled with difficult damage inspection. CFRP composites are susceptible to impact damage and growth of damage leads to sudden loss in structural integrity. Such damage often cannot be seen by the naked eye, and thus frequent inspection is required using expensive nondestructive testing equipment. This SBIR project addresses both of these obstacles by developing a gamechanging, lowcost Sustainable Lightweight Intelligent Composite SLIC, a natural fiberhybridized CFRP with self powered insitu selfhealth monitoring functionalities and improved crashworthiness critical for vehicle applications. The Phase I effort successfully demonstrated the feasibility of transforming structural materials into a piezoelectric sensor and a vibration energy harvester without requiring devices to be inserted. To realize this innovative idea, a novel circuit was developed that, for the first time, enabled simultaneous sensing and energy harvesting. This selfpowered selfsensing functionality was experimentally validated in Phase I. Building on this success, the proposed Phase II effort will further expand the SLIC functionalities to tackle both of the CFRP cost and reliability inspection obstacles. An additional novel complementary piezoresistive sensor will be created to not only enhance the reliability of insitu damage detection, but also to enable determination of damage location. Incorporation of natural fibers will not only reduce cost, but also improve crashworthinessthe most critical requirement for automotive vehicle structural materials. Multifunctional SLIC specimens including sensing and energy harvesting circuitry hardware and software will be created and evaluated through tensile, bending, impact loading and damaging tests. Finally, a scaled SLIC bumper beam will be molded to demonstrate the viability of SLIC in a major vehicle safety component. By delivering the proposed SLIC technology to address the two most significant obstacles, SLLC will accelerate widespread commercial adoption of lightweight fiber composites in automotive vehicles, which will result in enormous environmental and economic benefits. A 10% reduction in vehicle weight can improve fuel economy by 6%8% and every 100kilogram decrease in the weight of a vehicle cuts emission by 35%, according to recent studies. With the 50% weight reduction target and the use of sustainable recyclable lowcarbonfootprint natural fibers and processes, SLIC is perfectly aligned with the U.S. goal of netzero carbon emission by 2050. Production of lightweight lowemission vehicles will reduce the carbon tax burden on automakers and stimulate investment for growth and highpay jobs to American workers. SLIC’s lowcost lightweight selfhealth monitoring functionalities will directly benefit consumers, who will enjoy lowered costs of vehicles, fuels, and maintenance. The vehicle weight reduction will also cause less stress on the nation’s aging bridge and roadway infrastructure, saving expenditures on maintenance. In addition to the automotive industry, SLIC also has a huge opportunity to meet the unmet needs for lightweight and highly reliable structural materials in the aerospace and renewable wind energy industries.