Design and Analysis of a Custom Ankle Foot Orthosis (AFO) with Foot Drop Patient

Abstract

AbstractThe custom ankle foot orthosis (AFO) is an externally medical-assisted device used to support and improve the function of lower limb during walking and to modify the structural or functional characteristics of the neuromuscular system. There are two kinds of orthoses: custom and off-the-shelf. Custom orthoses give fit the patient’s body and better performance than off-the-shelf orthoses. The stringent design requirements such as light weight, small size, high efficiency, good mechanical properties and these challenges are subject to produce this device. There are two types of design AFO solid and hollow with three types of materials were used in this work, polypropylene (PP), composite materials of carbon fiber (CF) and a polylactic acid (PLA). The composite materials depend on the number of Perlon layers (12 layers, 10 layers and 6 layers) with two layers of carbon fiber and (6 layers) without carbon fiber. The mechanical properties of the AFOs’ materials were tested by tensile test and flexural bending test. The data of interface pressure were collected from one patient with drop foot (wearing three types of AFO) as the subject. Further, FEM by (ANSYS) was used to compute the safety factor of test for all types of AFOs’ models and the equivalent stress (von Misses). The interface pressure between the patient’s leg and the brace was tested by using a piezoelectric sensor. The results obtained from ANSYS gave the profile of safety factor of test, for (PLA-AFO) > (CF-AFO) > (PP-AFO).KeywordsOptimization designFinite element method (FEM)Ankle foot orthoses (AFO)Drop foot