The National Science Foundation (NSF) awarded a $230,000 Project Grant under the Mathematical and Physical Sciences program (CFDA 47.049) to the University of North Carolina at Chapel Hill for the period of August 1, 2023 to July 31, 2026. The research project will investigate and validate a new class of Cosserat rod models to describe the stretch-limiting behavior of biological fibers like DNA and RNA. Key expected deliverables include determining the fundamental properties of these models from a mathematical physics perspective, and contributing to the understanding and prediction of how fibers bend, twist, and stretch during biological processes. The research will also provide training opportunities for graduate students.