Preliminary Material Evaluation of Flax Fibers for Prosthetic Socket Fabrication

Abstract

Composite prosthetic sockets are typically made of fiberglass or carbon fiber. These fibers have good mechanical properties, but relatively poor vibration damping. Flax fibers are claimed to have exceptional vibration damping properties, with the added benefit of being a natural renewable resource and a cost-effective alternative to synthetic fibers. Flax fibers could prove beneficial for prosthetic sockets, providing lightweight sockets that reduce vibrations transmitted to the body during movement. This research used impact testing (impulse hammer and custom drop tower) on flat and socket shaped composite samples to evaluate composite layer options. Sample vibration dissipation was measured by a combination of accelerometers, load cells, and a dynamometer. Composite sockets made purely of flax fibers were lighter and more efficient at damping vibrations, reducing the amplification of vibrations by a factor of nearly four times better than sockets made purely of carbon fiber. However, the bending stiffness, elastic moduli, and flexural strength of flax sockets fabricated using the traditional socket manufacturing method were found to be ten times lower than theoretical values of flax composites found in the literature. By increasing fiber volume fraction when using the traditional socket manufacturing method, the composite's mechanical properties, namely, vibration damping, could improve and flax fiber benefits could be explored further.

Keywords: composite; flax; impact testing; modal analysis; natural fibers; prosthesis; socket; vibration damping.