Mechanical Evaluation of Adjustable Shoe Soles for Anisomelia Patients

Harunur Rashid, Muhammad Mizanur (2018) Mechanical Evaluation of Adjustable Shoe Soles for Anisomelia Patients. Final Year Project (Bachelor), Tunku Abdul Rahman University College.

Text MD MIZANUR - FULL THESIS.pdf Restricted to Registered users only Download (2MB)

Abstract

Mild leg length discrepancy patients are treated using shoe lifts. There are two design of shoe lifts which are either designed internally (insoles) or externally fixed to the sole. The commonly used materials for shoe lifts are cork, polyurethane rubber plastic. Recently adjustable heel lift or shoe lift has become popular among mild leg length discrepancy patients. Yet these types of shoe lifts are not suitable for patients’ ankle because it exerts high force on the patients’ ankle. The hind fool is elevated to high that causes Achilles tendon will have to compensate to balance the extreme force on the ankle. Greater injuries can occur if the ankle biomechanics do not stabilize the ankle against exerted forces. This research will investigate the normal stress across the adjustable shoe sole and conventional shoe lifts. Two shoe models of UK size 8 with three heights are tested. First model is conventional shoe lift with of height 3 cm and 5 cm while the second model is an adjustable shoe lift with a height of 5 cm with 2 cm adjustable. The material selected is polyurethane with specifications of density, ρ as 1.05 Mg/m3, Young’s Modulus, E equal to 0.002 GPa, yield stress, σy as 30 MPa, tensile stress, σts as 30 MPa and fracture toughness, KIC of 0.3MPa√m. The muscle force of 1856 N will act on the hind section of the shoe soles. The research conducted by performing simulation using Solidworks. Data gathered are stress, strain and displacement. The experiment focuses only on the maximum force exerted during plantarflexion movement. Conventional shoe lift of 3 cm has maximum stress of 565 MN/m2 during plantarflexion movement but when the height is 5 cm the maximum stress is 400.3 MN/m2. Adjustable shoe lift with a height 5 cm has a maximum stress of 350.6 MN/m2 during plantarflexion movement. The stress reduces when adjustable shoe lift introduced. Adjustable shoe lift is better choice for Anisomelia patients.