Tensile and Buckling of Prosthetic Pylon made from Hybrid Composite Materials

Abstract

Compared to traditional prosthetic pylon materials (Aluminum, Titanium, or Stainless steel.), composite prosthetic pylon materials are used instead of metals. Vacuum bagging technique was adopted for the preparation of specimens made of Poly methyl methacrylate (PMMA) as matrix with constant Perlon layers and different number of Hybrid (Carbon + Glass) fibers layers as reinforcement materials at (±45º&0º/90º) orientation relative to applied load. Also the finite element method (ANSYS-15) were used by create a model of prosthetic pylon and applied compressive load at heel strike step from gait cycle to known the critical buckling stress. The experimental and numerical results shown that the tensile strength, modulus of elasticity, and critical buckling stress increases with increasing number of Hybrid fibers layers, that equal to (145 MPa, 6.25 GPa, and 670 MPa) respectively, and the percentage of increase in tensile strength, modulus of elasticity, and critical buckling stress for specimen with three Hybrid (Carbon + Glass) layers and Perlon layers in PMMA resin compared with pure PMMA specimen was (302.7% , 300% & 257.22%) respectively, at (0º/90º) fibers orientation relative to tensile force. List of symbols Symbol Description E Modulus of elasticity R Radius of cylindrical shell t Thickness of cylindrical shell σ cr Critical buckling stress Passion's Ratio í µí°¾í µí±’ elastic stiffness matrix ∅í µí²Š Eigen vector í µí½€í µí²Š Eigen value for buckling mode í µí°¾í µí¼Ží µí°¿ the initial stress matrix INTRODUCTION prosthetic pylon with light weight, high strength, and also the most important factor is with low cost, the composite technology, is the best selection. Composite lamination polymers involve bonding the reinforcement layers together to create a lamination. This lamination process is performed under mechanical vacuum to give the prosthetic pylon good properties as compared with metal prosthetic pylon [1]. Composite materials have the important factor of low cost in addition to have good mechanical properties and ease of fabrication. Therefore, it is used in biomedical applications, prosthetic limb for socket and foot [2]. The researchers are studied in this field, Thurston, replaced the conventional rigid below knee prosthesis by using the glass fibers and resin composite material to form a