An Open-Access Fiber Management System for Recycling Filament Wound Structures

Composite overwrapped pressure vessels (COPVs) present a tractable recycling target as the production/recovery methods do not require cutting fibers, permitting recovery and re-spooling of continuous fiber tows. To address the gap between lab-scale recycling methods and commercial COPVs as a target application, an apparatus is required to control the unwinding process during recycling. A fiber management system (FMS) was designed and produced to maintain tension in the fiber tows and prevent tangles during unwinding filament-wound structures. To demonstrate the effects of the FMS, vitrimer composite tubes were produced, the matrix was dissolved, and recovered tows were used to produce a second tube. Second-generation specimens, some produced from tows unwound with the FMS as well as some from tows recovered manually, were cut into coupons and the tubular short-beam strength was measured. Specimens remanufactured with recovered tows unwound with the fiber management system exhibited an 11% increase in strength compared to specimens that were manually unwound (p = 0.048) and were statistically indistinguishable from first-generation tubes (p = 0.22). Maintaining control of the fiber tows resulted in full retention of mechanical properties in addition to automating and simplifying the unwinding process.