The case study of a brittle failure of a mountain bike frame composed by carbon fiber reinforced plastic

A mountain bike carbon reinforced polymeric frame failed in two pieces during cycling over a grass meadow at a speed of about 25 km/h. This has caused the shoulder dislocation of the driver, also last author of this paper. Here, we demonstrate evidence of macroscopic numerous pre-existing and propagating defects, such as wrinkles, voids and delaminations, resulting in low mechanical properties of this frame. Numerical dynamic simulations conclude the paper and suggest a further cause of frame weakening, due to defect-resonance interaction. The paper suggests that the design of carbon fiber reinforced plastic frame for mountain bikes may require new scientific and technological advancements for the safety of the riders, at least today carefully eliminating pre-existing defects and tomorrow proposing bioinspired flaw tolerant solutions.

Automated summary

A mountain bike carbon reinforced polymeric frame broke into two pieces while cycling over a grass meadow at a speed of 25 km/h, causing the rider to dislocate their shoulder. The study reveals the presence of multiple existing and spreading macroscopic defects, such as wrinkles, voids, and delaminations, resulting in low mechanical properties of the frame. Numerical dynamic simulations suggest that defect-resonance interaction is a contributing factor to frame weakening. The paper highlights the need for new scientific and technological advancements in designing carbon fiber reinforced plastic frames for mountain bikes, emphasizing the importance of eliminating pre-existing defects and proposing flaw tolerant solutions inspired by nature.