Simulation and optimization of materials used for prosthetic leg for above-knee amputees using MR fluid

The lower limb amputees are increasing day by day. This has led to an increase in research in the field of prosthetic legs. Prosthetic legs can be either active or passive. The active ones can behave very closely to the human leg. This means that they can provide adequate torques and forces for the ease of movement of the amputee. The downside of such prostheses is that they are too expensive thus being unaffordable for a lot of people. The passive type of prosthetic legs are very cheap as compared to the active ones, but they can't provide the torque required for walking. Thus, the amputees with a passive prosthetic leg walk awkwardly. A semi-active prosthetic leg can behave closely like a natural leg and is also not very expensive. This can be achieved using MR Damper, which operates only in the stance phase. The MR Damper consists of an MR fluid, a smart material that changes its behaviour according to the magnetic field around it. It can be controlled using a PID controller, to produce the required current and hence the magnetic field. Apart from this, an ankle joint with 2 DOF can be provided for further ease of movement for a potential application. The choice of the material for MR Damper and the ankle for their effective working as well as to make a lighter prosthesis is an important decision. MR Damper needs to have a magnetic core. Iron and steel core has been simulated to see the variation of magnetic flux density and the magnetic contour lines. The most important factor for this analysis is the relative permeability of the material. For the ankle to work properly, it should be able to withstand the stresses and also have a factor of safety more than 1 at all points. Aluminium alloy, being a lighter material than steel can be used . (c) 2021 Elsevier Ltd. All rights reserved. Second International Conference on Aspects of Materials Science and Engineering (ICAMSE 2021).

Automated summary

With the increasing number of lower limb amputees, research on prosthetic legs has been growing. Active prosthetic legs closely mimic human legs but are expensive; passive prosthetic legs are cheaper but lack adequate torque. Semi-active prosthetic legs provide a balance between natural movement and affordability.