Algorithmic design of functionally graded prosthetic liners

Additive manufacturing now allows us to create multi-material and structurally complex composite products. Can functionally graded materials provide a better skin interface for prosthetic users?

Start date:           1 Feb 2023

End date:             31 July 2023

PI:                        Dr Ben Oldfrey (UCL)

Co-Is:                   Dr Alex Dickinson (University of Southampton)

                             Dr Elze Porte (UCL)

                             Dr Joshua Steer (University of Southampton and Radii Devices)

Additive manufacturing now allows multi-material and structurally complex composite products that could not previously be created. This unlocks our ability to replicate many advantageous structures found in biological tissues.

Nature creates incredible interfacing mediums between hard and soft materials in the body by gradation of connecting tissues. This spreads the stresses being translated through, for example tendons and ligaments, rather than concentrating stress at specific points, increasing damage tolerance.

Stress management and comfort at the prosthetic socket interface is an ongoing challenge, in particular combating shear stresses. While graded stress profiles at the stump socket interface could inherently reduce wear and improve component life spans and therefore improving the sustainability of devices, complex composite material structures are in opposition to design guidelines that facilitate material recovery and standard sustainability strategies.

New repairability or life-prolonging strategies must be devised for these structures, such as the re-application of soft layers to maintain surface integrity or to protect emergent sites of local tissue sensitivity or vulnerability.

The work would build on materials development work at UCL on soft material structures, and predictive socket design and modelling work at University of Southampton (and the spin out company Radii Devices).

Research Question 1: Can functionally graded materials provide a better skin interface for prosthetic users?

Research Question 2: Can stress profiling be optimised for both comfort and wear reduction?

Research Question 3: How can repair strategies that complement these material structures be developed to prolong product life?