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The suspension systems in automobile are required to provide optimum ride comfort and vehicle handling. As these two performance parameters are in contradiction with each other in automobiles fitted with regular passive suspension systems, various studies are being conducted to identify an alternative system that can optimise both the parameters. One such alternative is presented in the form of Magnetorheological (MR) damper, a most viable semiactive device. A MR damper comprises of MR fluid that consists of carbonyl iron powder and silicone oil added with additive. The characteristic of this damper has been established experimentally, which in turn is used to identify the parameters of spencer model for MR damper. Using spencer model of MR damper, at 5 different currents, viz.,0A, 0.25A, 0.5A, 0.75A, 1A, the half-car models of vehicle suspension system of a car and a multi axle truck are simulated for analysing the ride comfort and vehicle handling. The ride comfort and vehicle handling performance of each specific vehicle model with passive suspension system are compared with corresponding skyhook, ground hook and hybrid control semi-active suspension systems. The simulation and analysis are carried out using MATLAB/Simulink. [ABSTRACT FROM AUTHOR]

The effect of roselle fabric weave pattern on water absorption and thickness swelling behaviour of woven roselle fibre composites has been investigated. Roselle fabrics with various weaving design such as plain, twill, satin and basket are used in this study. All composites are produced using hand layup process. The water absorption and thickness swelling behaviour of all composites are studied as per ASTM standards. The test samples were immersed in distilled water at room temperature and change in weight and thickness of the test samples recorded at every 24 hour time interval. For all composite samples, saturation in water absorption and thickness swelling was observed after 264 hours of water immersion. Result revealed that the plain-woven composite yields higher resistance to water absorption and thickness swelling than other types of composites. [ABSTRACT FROM AUTHOR]

The effect of fibre orientation on the tensile and dynamic mechanical performance of stacked Roselle fibre epoxy composites has been investigated. The hand layup method is employed to produce 0 °/90 °, 0 °/45 ° and ± 45 ° oriented Roselle fibre epoxy composites. The tensile test and dynamic mechanical analysis (DMA) were conducted as per ASTM standards. Results revealed that the tensile strength of 0 °/45 ° oriented Roselle fibre composite is 341% more than neat epoxy, 44% higher than 0 °/90 ° oriented composite and 106% greater than ± 45 ° oriented composite. As compared to pure resin, composites possess enhanced storage modulus. The composite with 0 °/45 ° orientation has higher storage modulus value than other composites. All Roselle fibre composites have up to 15% reduced glass transition temperature as compared to neat epoxy. SEM images cover the fibre pull-out and the presence of micro-voids in the epoxy matrix. [ABSTRACT FROM AUTHOR]

The two main issues to be addressed in the design of automotive suspension systems are ride comfort and vehicle handling. The option systems are being studied because passive systems provide contrariety on these two parameters. One such choice is the magnetorheological (MR) damper, a highly feasible semi-active system that can address both of these issues while overcoming inconsistency. In this analysis, the suspension system of a tractor with MR damper is analysed for ride comfort and handling at 5 different currents, namely 0A, 0.25A, 0.5A, 0.75A, and 1A, using a 2DOF tractor, and the comparisons are made with the same suspension fitted with standard passive damper. A MR-damper is made of MR fluid, which is made up of carbonyl iron powder and silicon oil, along with a triton x-100 and grease additive. Furthermore, the characteristics of this damper are determined by experiments, which are then used to determine the parameters of the Spencer model for MR damper. The tractor suspension system is simulated by implementing a semi-active suspension system using the Spencer model of MR damper at 5 different currents for testing the resulting displacement and acceleration in the tractor body. The ride comfort and vehicle handling efficiency of each model with a passive suspension system was compared to semi-active suspension systems based on skyhook controller. MATLAB/Simulink is used to carry out the simulation and analysis. [ABSTRACT FROM AUTHOR]