Experimental and finite element analysis of porous functionally graded blend (PLA\UHMWPE/PVA)

Abstract

To simulate the structure of living tissues and find alternatives with similar properties, and to reduce the differences between orthopedic and hip implants, functional grading is used to fabricate artificial replacements for a part of the knee joint, study their mechanical properties, and analyze the results using the finite element method. Functionally graded blends (10%-50% wt. PLA)/ (90%-50% wt. UHMWPE)/ 50% wt. PVA) are used. A porous implant is chosen instead of a solid one to reduce the stress-shielding effect. Finite element analysis (FEA) is used to analyze the stress-shielding effect of FGB under the loads acting on porous hip implants as an alternative to dense stems. Hardness and tensile tests are performed to analyze the behavior of functionally graded blend samples and a functionally graded porous hip implant model under critical loads, and are analyzed using a digital microscope to determine the count and average pore size. The implant design is found to be sensitive to the functional grading factor. Under tensile conditions, when the prosthetic leg model (PFGBs) structure takes a gradient according to stiffness values from the lowest (39.08) to the highest (46.9), dislocation and loosening are observed at the maximum tensile force at a displacement of (50 mm) for the highest total deformation of (16.564 mm) and the maximum von Mises stress of (12.736 MPa). While the prosthetic leg model under tension, when the (PFGBs) structure takes a gradient according to stiffness values from the highest (46.9) to the lowest (39.08), dislocation and loosening occur at the maximum tensile force and at the point of contact of the ball head with the leg under tensile loading conditions at a displacement of (50 mm) for the highest total deformation of (18.904 mm) and the maximum von Mises stress of (22.559 MPa).