Self-Sensing Self-Sustaining Carbon Fiber-Reinforced Polymer (S4CFRP) Composites for Next-Generation Vehicles

Carbon fiber-reinforced polymer (CFRP) composites offers the greatest potential for weight reduction in automotive vehicles, resulting in improved fuel efficiency and lowered CO2 emission. However, a major obstacle to broad commercial deployment is the high- cost and insufficient inspection of invisible damage. CFRP composites are susceptible to impact damage, resulting in significant loss of strength and stiffness without sign of damage on the surface. Unknown aging effects of CFRP composites also cause reliability concerns. Therefore, frequent inspection is required by trained personnel using expensive nondestructive testing equipment. To address this obstacle, this project develops a groundbreaking self-sensing self-sustaining CFRP (S4CFRP) composites system that can detect and warn users of any damage at the moment when it occurs. The system is entirely powered by energy self-harvested from vehicle vibration. The key innovation of the S4CFRP composites is in the transformation of structural materials, i.e., the carbon fiber and polymer, into an integrated sensor and energy harvester, without requiring any additional materials or devices to be inserted. In other words, the S4CFRPTM composites are a new lightweight multifunctional structural material integrated with self-sustaining self-sensing intelligence that enhances the structural safety and reliability with virtually no added cost or weight. The S4CFRPTM composites are a novel concept which has never been studied for integrated self-sensing and energy harvesting. The Phase I objective is to design and create S4CFRPTM composites specimens and experimentally demonstrate their feasibility of continuous monitoring and real-time damage detection, using the energy self-harvested from vehicle vibration. The S4CFRP composites specimens will be fabricated along with low-power circuits with embedded software. They will be experimentally evaluated in terms of sensitivity to damage and efficiency of energy harvesting. Major technical challenges are anticipated such as how to distinguish damage signals from vehicle vibration signals. Leveraging their significant experience in related R&D areas, the project team has laid out novel approaches to tackle these challenges and demonstrate the technology feasibility by the end of Phase I. The goal is to make the S4CFRP composites ready for commercialization by the end of SBIR Phase II, in which the project team will collaborate with automakers and suppliers to develop a prototype vehicle structural component and conduct large- scale tests. Because of the multiple important functionalities created in the lightweight CFRP composites without increasing cost or weight, S4CFRP composites are expected to be adopted by the automotive industry. By addressing the safety and reliability obstacle, S4CFRP will help accelerate the commercialization of lightweight CFRP vehicles. The resulting vehicle weight reduction will improve fuel efficiency and reduce CO2 emission. Lighter vehicle weight will also alleviate stress on roads and bridges, resulting in savings in maintenance cost of aging transportation infrastructure. Furthermore, the S4CFRP composites will enable novel applications in aviation, wind energy, medical and many other industries, making a long lasting impact to the quality of life and economic prosperity while preserving the environment.