Ultrasonic vibration assisted grinding (UAG) has proven to lower the forces and improve the ground surface quality while shaping difficult to grind materials such as ceramics. A systematic study of UAG of alumina ceramic using a metal bonded diamond grinding wheel has been performed here. Taguchi’s L18 array based experimentation has been performed to study the effect of UAG parameters. During UAG, the vibration amplitudes of 6 and 12 microns have been used and the frequency has been kept at 20 kHz. From these experiments, optimum parameters for UAG have been identified using Grey relational analysis. Mathematical models generated using regression analysis have been found to correlate the experimental data with good accuracy. A comparison of the grinding forces and roughness of the surfaces generated in dry and minimum quantity lubrication (MQL) conditions in both conventional grinding and optimal condition in UAG has been performed to identify the beneficial effects of providing vibration to the workpiece. The surface quality has been evaluated using 3D roughness data, 3D plots and SEM images of the ground surface. By examining nature of the ground surface and kurtosis (S_ku) values of the surface profile, it has been concluded that UAG reduces brittle fracture and facilitates material removal by ductile mode for alumina. The desired condition of least machining forces and highest surface quality has been achieved during the combination of UAG and MQL.

This study presents a detailed experimental investigation on the effects incorporating non-metallic fibers in hybrid form in self-compacting concrete (SCC). In this regard SCC was prepared with Alccofine and Metakaolin as partial replacement for cement in 15% and 20% respectively along with the hybrid fibre combinations namely abaca fibres (0.25%, 0.5% & 0.75%), polypropylene fibres (0.5%, 1%, 1.5% & 2%) and glass fibres (0.5%, 1%, 1.5%, & 2%). The fresh properties of SCC with and without hybrid fibre combinations were assessed through the standard tests such as slump flow, J ring and V-funnel tests. The conventional mechanical tests such as compressive strength test, split tensile strength test and flexural strength test were performed at 7 and 28 days. The experimental results reveal that the fresh properties of SCC were highly influenced by alccofine and Metakaolin adopted in this research. Furthermore, that the hybrid combination of abaca with polypropylene and glass fibres improved the mechanical properties of SCC and in particular the mix with 1% glass fibre and 0.25% Abaca fibre had shown better flexural and tensile strength behaviour. Microstructure analyses were also done to confirm the improvement in mechanical properties. The Scanning Electron Microscope images of the mix with 1% glass fibre and 0.25% abaca fibre showed less voids presence and presence of more hydrated components conveying that the usage of hybrid fibres had restricted the propagation of cracks there by reducing the percentage of voids and the use of metakaolin and alcofine helping in forming hydrated components at earlier stage leading to better strength.

Ultrasonic vibration-assisted grinding (UVAG) has proven to be beneficial for grinding difficult-to-machine materials. This work attempts to enhance the grinding performance of Inconel 718 through a comprehensive study of UVAG characteristics. Grinding experiments were performed in both dry and Minimum Quantity Lubrication (MQL) environments, and assessment of the grinding forces, specific energy, residual stress, and surface topography was done. A substantial reduction of both surface roughness and grinding force components was observed in UVAG compared to conventional grinding (CG). Utilizing UVAG with MQL at the maximum vibration amplitude led to a 64% reduction in tangential grinding force and a 51% decrease in roughness parameter, R_a, when compared to CG conducted in a dry environment. The high-frequency indentations of the abrasives in UVAG generated compressive residual stresses on the ground surface. Surface parameters pointed to uniform texture and SEM images showed widening of abrasive grain tracks on the workpiece surface during UVAG. The utilization of UVAG under MQL produced a synergistic impact and resulted in the lowest grinding forces, specific energy, and optimal surface quality among all the grinding conditions investigated. Overall analysis of the results indicated that the axial configuration of the vibration set-up is favorable for UVAG, and the high-frequency periodic separation-cutting characteristic of the process improves lubricating efficiency and grinding performance.