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Right from the outset of the experimental determination of rock stress-strain response, researchers are performing uniaxial and tri-axial compression testing on the cylindrical specimens. In the last two-three decades' researchers have made an attempt to develop constitutive model considering anisotropy, rheological behavior and flaws in rock. In this project, static uniaxial compression tests are performed on cylindrical specimens of Kota sandstone, dolomitic limestone and three weathering classes of Delhi quartzite. Stress-strain curves have been plotted and a general constitutive model equation is derived for all the rock specimens. By observing stress-strain plot of different rock specimen, a parabolic relation between stress and strain is proposed containing two parameters m and n. The fitted results by these models for all types of rock are compared with the experimental data and with the Hooke's law. It is concluded that the amended damage constitutive model can describe the stress-strain behavior of rock quite accurately.

The present investigation is carried out to study the swelling and thermal behaviours of alkali treated cellulosic fibre (sisal and jute) with fly ash dispersed unsaturated polyester composites. These composites are fabricated by compression moulding with a filler loading of 5, 15, 25, 35, and 45 wt. %. The electronic thermal insulation tester, differential scanning calorimeter, and thermo-gravimetric analyzer are used for thermal analyses of the synthesized composites. It was observed that the thermal stability and degradation temperature of the composites improved significantly with addition of the filler within the unsaturated polyester resin.The swelling behaviours are determined by immersing the synthesized samples in the different pH content of water. In case of swelling behaviours, the changes in water absorption are quite acceptable as compared to the treatment time and the atmospheric condition. The fabricated composites displayed optimum results for filler content with 35 wt. % followed by saturation in properties with the dispersion above the same.

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A synthetic composite material membrane was synthesized using Polyether ether ketone (PEEK) as a polymer matrix, reinforced with nano-Hydroxyapatite (nHAp) as the ceramic for intended use as a hip bone implant material. Notwithstanding its close resemblance with hip bone material, PEEK is chemically and biologically inert and comes with limited biocompatibility. HAp has chemical and crystallographic similarity with carbonated apatite like human bones. In the present work it was used as reinforcement with PEEK in varying weight percentages, of 2, 5, 8 and 10 to determine the optimum mix for application as a bio hip implant material. HAp reinforcement beyond 10 wt. % was not considered as it resulted in agglomeration and reduction in mechanical properties. The polymer was sulphonated to facilitate chemical interactions with the hydroxyl (-OH) group of HAp to overcome poor interfacial bonding between PEEK and nHAp. The sulphonation also reduced the chances of wear debris from implant site getting resorbed into the body. These synthetic composite samples were then characterized using techniques such as x-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscope and energy dispersive x-ray spectroscopy, to ascertain its conformity in structure and morphology. Mechanical tensile tests were also carried out to determine tensile strength, yield strength and elastic modulus of the composite membranes. The synthesized sample, with 8 wt. % of HAp reinforcement, demonstrated the most suitable properties. The work propounds a fresh approach towards synthesizing a composite membrane using Polyether ether ketone, subjected to sulphonation (SPEEK), for intended application as a hip implant. The superior surface wetting, obtained on account of sulphonation of PEEK matrix, facilitated more intimate contact with nano-hydroxyapatite (nHAp) reinforcements and assisted in establishing superior, homogeneous and improved mechanical properties throughout the membrane.