a) The fuel storage yard is separated from the main plant by a swing bridge (swinging in a horizontal plane). The motor driving the bridge requires replacement necessitating an analysis of torque requirements. The bridge must swing through an angle of 90o in 120s. The bridge accelerates uniformly for 40s then moves at a constant velocity, decelerating uniformly to rest in the final 20s.The rotating components of the bridge have an equivalent moment of inertia of 103 kgm2 and feel a constant resisting torque of 300Nm. Find the torque required for the three stages of motion.
b) A problem has arisen in the goods yard where a large container is required to be pulled along a makeshift horizontal slipway by a rope wound around a winding drum. See below. The container has a mass of 1.5 tonne and is pulled along the horizontal slipway at an acceleration of 0.9m/s2. The resistance to motion of the container is equivalent to a co-efficient of friction of 0.6. The winding drum has a mass of 0.5tonne, outside diameter of 1m and radius of gyration of 0.3m. The drum has a resistance couple of 200Nm acting on it. Find the torque required by the motor of the winding drum.
In the assessment of a buffers performance, a railway carriage of mass 6 tonne is allowed to roll freely down an incline of 1 in 20 (sine) for a distance of 50m into a horizontal yard. At the end of the yard it is brought to rest by a pair of parallel buffer springs. The stiffness of each spring is 30kNim and the initial resisting force in each spring before impact is 4.5kN. Using an energy method calculate the maximum compression of the springs.