Preliminary Material Evaluation of Flax Fibers for Prosthetic Socket Fabrication.

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.

Simplified setup for the vibration study of plates with simply-supported boundary conditions.

The experimental study of vibrating plates having simply-supported boundary conditions can be difficult to achieve due to the complexity of preventing translation, but allowing rotation along all boundaries simultaneously. Only a few methods have been proposed, but all are either time-consuming to set up and involve customization of the test rig for each plate or do not allow the plate to be reused for other purposes. The method described in this paper offers a low-cost, simple, accurate and non-destructive way of experimentally measuring the modal properties of thin, simply supported plates and can be used for quick validations of models and designs without modification for multiple trials and varying plate properties. The key attributes of this method include: •An adjustable sliding support frame which can be made of a distinct material from the plate and which can accommodate variations in plate geometry and properties without modification.•Removable flexible sealant applied in a v-groove on the supporting frame which can be easily used to fix and support the plate according to the simply-supported boundary conditions.•A low-profile design, which can be used to accommodate most experimental testing methods for determining modal properties of vibrating plates.