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Stress shielding is a mechanical phenomenon usually found in load-bearing bone implants. Difference in mechanical properties between the natural bone and the artificial implant leads to stress shielding problem. In the present work, polymethyl methacrylate and commercial pure titanium were selected to design laminate and particulate composites. Optimum composition was theoretically obtained that exhibits mechanical properties close to that of natural human bone. Bone fixing plate was designed for femur bone using computer-aided design. Finite element analysis was adopted to analyze the stress distribution in the bone and implant under static load conditions. Fixing plate with three screws was modeled and simulated using finite element analysis to investigate the stress distribution. Simulation was also done considering 316 L stainless steel as fixing implant and compared with the present optimized composition. Laminate composite with 0.3 volume fraction of titanium has shown mechanical properties close to the bone compared with other combinations. The results have clearly shown that the von-Mises stress induced in the bone with polymethyl methacrylate-titanium laminate composite plates was increased compared with the bone implanted with 316 L steel. Interestingly, laminate composites exhibited higher stresses in the bone compared with particulate composites. From the present design and simulation, it is clearly demonstrated that the laminate composites of polymethyl methacrylate–30% titanium can be an optimum choice for load-bearing implant materials with reduced stress shielding effect. [ABSTRACT FROM AUTHOR]

The present work focuses on the experimental evaluation of the performance of vegetable oil based nanofluids during turning. Nanofluids are prepared by dispersing suspensions of two types of solid lubricants namely, nano-boric acid (nBA) and nano-molybdenum disulphide (nMoS2) individually in two vegetable oils which are, coconut oil (CC) and sesame oil (SS). After thorough sonication, the formulated nanofluids are applied as lubricants while turning AISI 1040 steel. The fluids with and without nanoparticle inclusions (npi) are tested for basic properties like flash and fire points, kinematic viscosity, and thermal conductivity. To estimate the performance of nanofluids as lubricants, machining parameters namely main cutting force, cutting tool temperatures, surface roughness, and tool flank wear are measured. Viscosity and thermal conductivity of CC-based nanofluids is found to be better when compared to those of SS. Improvement in machining performance is observed by the application of nanofluids. CC + nMoS2 at 0.25% and 0.5% npi has shown reduction in cutting forces, cutting temperatures, tool flank wear, and surface roughness when compared to sesame oil based nanofluids. On an average, nMoS2 suspensions in CC at 0.5% npi have shown 9–13% and 20–25%, reduction in cutting forces, cutting temperatures, tool flank wear, and surface roughness respectively when compared to nBA counterparts in CC and SS at all npi. [ABSTRACT FROM AUTHOR]

The application of conventional cutting fluids as lubricants during machining operations is not user-friendly and eco-friendly. Owing to this reason, new eco-friendly and user-friendly alternatives to these cutting fluids are being extensively researched. In this context, the present work focuses on preparation of vegetable oil–based micro and nano cutting fluids, followed by evaluation of their applicability in machining. The comparative performance of micro and nano cutting fluids is consolidated and presented in this work. Micro and nano solid lubricants, namely, boric acid (H3BO3) and molybdenum disulphide (MoS2), are mixed with coconut and sesame oils separately and sonicated thoroughly. The samples thus prepared are used in machining for the examination of cutting forces, cutting temperatures, tool wear, and surface roughness in order to assess machining performance of the cutting fluid at the specific cutting conditions. It is observed that performance of nanofluids is better than micro fluids in reducing cutting temperatures, cutting forces, tool flank wear, and surface roughness of the machined surface. [ABSTRACT FROM AUTHOR]