Harvesting energy from ambient sources has been a recent topic of interest. A typical linear harvester is effective only near resonance, limiting its frequency bandwidth. In order to increase the efficiency and bandwidth of harvesters, various strategies have been proposed. Using multiple harvesters in a single device can harvest enough power over wider frequency band. In the present work, the effect of torsional coupling of the harvesters for low frequency vibration energy harvesting is investigated. Two pendulums with electromagnetic induction as the energy conversion mechanism is proposed. The performance of the device is studied theoretically and numerically. Cubic polynomials are used to model the pendulum nonlinearity. Fundamental harmonic oscillation are assumed to obtain the analytical solution. The effect of torsional coupling and pendulum length on the power harvested are reported.

No abstract

The objective of this study is to validate the experimental modal analysis of bumper results with numerical modal analysis of bumper. The bumper model is created through CATIA V5 R20, meshing and analysis is done through HYPERMESH and OPTISTRUCT respectively. The main aim of the modal analysis is to find out natural frequency, mode shapes to avoid failure of car parts. If the natural frequencies of bumper or any other parts equal to natural frequency of the engine system leads to failure of system. Impact analysis is carried through ANSYS LS DYNA workbench which determines deformation and acceleration. Hence we design the bumper system, such a way that natural frequency of bumper and any other car parts should not coincide. Experimental results shows low values compare to the numerical results. The impact test is carried out at speed of 48km/h (13926 mm/s), in order to determine the deformation and acceleration. The new bumper model has lesser deformation and acceleration compare to old model, thereby it reduces the impact energy transformation and it will reduce the injuries to passengers.

Looking at the present scenario of world’s energy consumption and its dependency on fossil fuels, biodiesel has become a ray of hope as it is environmental friendly fuel derived from plant sources. In that context the present paper reports the study of physical properties of Mahua, Pongamia and Waste cooking oil blend for usage as biodiesels in engines. Each biodiesel has its own specific properties which need to be tested before running test on a engine. The physical properties such as kinematic viscosity, flash point, fire point, density, heating values and acid values are measured for MPW (Mahua 50%, Pongamia 30%, Waste Cooking Oil 20%), PWM (Pongamia 50%, Waste Cooking Oil 30%, Mahua 20%) and WMP (Waste Cooking Oil 50%, Mahua 30%, Pongamia 20%) compositions prepared on volume basis. This study discovered that WMP biodiesel physical properties match nearly to that of diesel fuel. It is the best alternative with moderate flash point temperature, fire point temperature, better thermal efficiency, density and acid value in comparison with MPW and PWM biodiesels.