INTERNATIONAL JOURNAL OF ENERGY AND ENVIRONMENT Volume 9, Issue 3, 2018 pp.283-294 Journal homepage: www.IJEE.IEEFoundation.org ISSN 2076-2895 (Print), ISSN 2076-2909 (Online) ©2018 International Energy & Environment Foundation. All rights reserved. Effect of the carbon nanotube (CNT) in the materials used for prosthetics and orthotics applications Jumaa S. Chiad, Wajdi Sadik, Abbas Hameed Jeryo Department of Mechanical Engineering, College of Engineering, Al-Nahrain University, Baghdad, Iraq. Received 20 Oct. 2017; Received in revised form 20 Nov. 2017; Accepted 29 Nov. 2017; Available online 1 May 2018 Abstract In this work, the optimal mechanical properties of the lamination materials that used in manufacturing prosthesis and orthoses parts are studied. The optimization is selected according to high yield, ultimate stresses, bending stress and fatigue properties. The method of selection the optimal materials is a response surface methodology (RSM) which depend on two parameters, reinforcement material Perlon fiber and percentage of multi-wall carbon nanotube MWCNTs which is mixed with matrix lamination resin. Thirteen samples are suggested according to RSM method by controlling two variables which are the layers number for Perlon and MWCNTs percentage. This method leads to select the optimum materials which give a maximum yield, ultimate and bending stresses. According to ASTM D638 and D790, the three imported tests are performed which are tensile, three-point bending and fatigue tests for all laminations materials as selected by RSM method and manufactured by vacuum method. Also, fatigue test is performed for optimal lamination material and compared with laminations manufactured in the previous study, 10 layers Perlon lamination and 424 laminations (4Perlon, 2carbon fiber and 4Perlon). The results obtained by Design Expert program version 10.0.2 showed that the lamination (10 layers Perlon and 0.75%of MWCNTs) is the optimum lamination according to the maximum yield, ultimate and bending stresses, and, endurance stress. Copyright © 2018 International Energy and Environment Foundation - All rights reserved. Keywords: Mechanical and fatigue properties; Response surface methodology (RSM); Perlon layers; Multiwall carbon nanotube (MWCNTs). 1. Introduction Recently, researchers have shown an increased interest in prosthesis and orthoses because of many patients suffering from loss their limbs as a result of amputation or a birth defect. The prosthesis is an artificial replacement for any missing part of the body, while orthoses is an outer device using in the body part to provide one or more deferent capacity include, decreasing a pain, correct deformity, improvement in a function, assist motion or augment weak muscles, control spastic muscles and others functions [1]. After World War II, advanced in prostheses were remarkable. New fitting techniques, new materials and new concepts of design all aided the amputee. There was no similar technologic progress in orthotics, however. Recently the early 1970s seemed appropriate to appear the field of orthoses as the most Prominent, parochial and provincial portion of orthopedic surgery and rehabilitation [2]. The lower limbs orthoses or prostheses explores to fatigue and outer load for this reasons, studying and enhancement of mechanical