A Numerical Simulation for the Ankle Foot Orthosis Using the Finite Element Technique with the Aid of an Experimental Program

Ankle-foot orthosis (AFO) is a device that supports the ankle and foot part of the body when there is a muscle weakness or a nerve damage, Ankle-foot orthoses are prescribed to individuals with minimal spinal cord injury and excellent trunk muscle control (AFOs). In this paper, two types of composite laminates were used in the experimental program. The first sequence of layers arranged as follows, (2Perlon + 1Carbon fiber + 2Perlon + 1Kevlar + 2Perlon) called Sequence1. And the other sequence is (2Perlon + 3Carbon fiber + 2Perlon + 3Kevlar + 2Perlon) called Sequence2. In the numerical investigation, the performance of the AFO materials is evaluated using mechanical qualities such as fatigue and tensile testing. This study uses FEM as a numerical technique to demonstrate the impact of fatigue performance on a structural element with the assistance of ANSYS Workbench 14 software. It is used to predict how total deformation, maximum stress, fatigue life, and safety factor will behave. The experimental results have shown that the ultimate tensile stress was 67 MPa and 80 MPa for the first and second type of layers respectively. The patient’s height (176 cm), weight (78 kg), and approximate age of 39 and he was suffered from drop foot. By using FEM (ANSYS) (Von-Mises), the equivalent stress and safety factor of the fatigue have been calculated for the provided AFO model. The resulting ANSYS findings are shown that the profiles of the fatigue safety factors for the composite material (sequence1) AFO equal to 2.86211, for the composite material (sequence2) AFO equal to 3.68318, and for the Polypropylene AFO equal to 1.90683. The difference between the yield stresses of composite material and the highest stresses is produced by the orthosis which indicates the feasibility of the notion that composite materials can support the patient’s weight and serve as an alternative to the materials currently is employed to make the AFO. Where the highest stresses of the PP and composite material (sequence1) AFO are equal to 18.033 MPa, and for composite material (sequence 2) AFO is equal to 17.583 MPa and yield strength for composite material (sequence 1) (50 MPa), yield strength for composite material (sequence 2) (63 MPa) compared to polypropylene’s yield stress of 24.3 MPa.