CAREER: Understanding Ultrasonic Processing of Layered Polymer Composites Across Length Scales

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This Faculty Early Career Development (CAREER) Program grant supports research contributing to the understanding that underpins the ultrasonic processing of fiber-reinforced polymer composites, promoting both the progress of science and revitalizing the U.S. manufacturing industry. Composite materials possess high strength and low weight, as compared to conventional materials like metals, which can be tailored according to fiber orientation and layer sequence. Certain polymer composites offer further sustainability because they may be reformed at high temperatures, recycled, and joined through fusion bonding. Current manufacturing techniques typically require high temperature and expensive tooling, which limits the use of thermoplastic composites as primary structural components in a wide range of industries. In the search for energy and cost-efficient manufacturing and assembly techniques, processing through ultrasonic vibrations is a promising candidate that can achieve consolidation and bonding in a fraction of the time required by traditional methods. This fundamental research furthers the development of ultrasonic processing of composites, advancing growth of several applications in aerospace, transportation, maritime, piping, and wind energy industries. An integrated outreach plan includes hands-on activities to engage a diverse population of K-12 girls, as well as training of undergraduate and graduate students through senior design projects and technical elective courses. This will result in a highly trained workforce for the composites manufacturing industry and thus, will support national prosperity.The challenges in the use of ultrasonic processing for polymer composites are due, in part, to the difficulty in experimentally capturing the detailed processes of occurring at the interface due to ultra-fast cycle times and geometrical constraints to the region of interest. This proposal addresses those challenges by elucidating processing-structure-performance relationships and establishing novel experimental and modeling solutions. More specifically, it will address two main research objectives: 1) understand how ultrasonic and material parameters govern heat generation and crystallization mechanisms through multiscale experiments (from molecular structure to macro-scale); and 2) establish a multiphysics finite element model based on experimental outcomes to simulate the process and predict bonding efficiency. Achieving greater understanding of this process will allow scale up and confident deployment for critical applications.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.