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In this study, we adopt different material models to study the strength and stiffness of menisci of the knee joint using finite element method. The three-dimensional (3-D) knee joint finite element model is constructed based on the Magnetic Resonance (MR) images of a human knee joint, and the strength of menisci is analyzed under a specific vertical loading case. In this paper we categorize and implement three types of appropriate material properties, namely isotropic linearly elastic, transversely isotropic elastic and isotropic hyperelastic for menisci of the knee joint. Different strain energy models are also studied and compared under hyperelastic category. The comparative study demonstrates that the hyperelastic model with Ogden form is more appropriate in modeling menisci of the knee joint. By referring to the test data of different material properties from earlier studies by various researchers, we hope to provide a comparative study leading to appropriate menisci material models and properties for finite element analyses of knee joint structures.

Synthetic biopolymer blends are gaining interest in the packaging industry because the incorporation of natural materials imparts biodegradable properties to films. In this study, polyethylene/chitosan (chitosan) films with thicknesses of about 0.3 6 0.01 mm were fabricated via compression molding. The effects of the variation in the length of compounding as a function of the length/diameter (l/d) ratio (15:1, 30:1, 45:1, 60:1, and 75:1) were investigated. The experimental results show that a higher degree of miscibility of the blends was achieved with increasing compounding length; this led to improved mechanical properties in the films, and this was verified by the statistical analysis of data with the analysis of variance procedure. The tensile strength (TS) increased by about 25%, whereas the elongation at break (E break ) increased by twofold. Films fabricated from blends compounded with an l/d ratio of 60:1 had the highest TS and E break values, and the TS was comparable to that of low-density polyethylene films. V C 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43796.