Capstone project

Vibration demonstrator

The vibration demonstrator was intended to be used as a desk top demonstration device. The Supporting Structure was built from aluminum. Aluminum was not only chosen for its strength and light weight, but it was also chosen because it was an easy metal to machine. The motor and shaft bearing are framed onto a rectangular plate and the plate hangs from each of its comers by four springs attached to the top of the support structure. The two matching flywheels are supported by the two bearings, and each have twelve tapped holes around their outer edges. Various combinations of masses can be screwed on to the tapped holes to unbalance the flywheels. As the motor rotates the unbalanced flywheels, a vibration will be generated which causes the motor and bearings frame to oscillate vertically. A piston cylinder is attached to the oscillating plate to dampen the oscillation. The cylinder's damping effect can be increased or decreased by opening or closing the valves on the cylinder's air ports. The vibration can also be changed by varying the speed of the motor. The motor has a range, between 100 rpm to 1200 rpm. A motor shaft counter device using reflected light enabled me to obtain the speed of the prime mover. Even the spring constant of the system can be changed by replacing the four springs by four springs of a different rate (k). The bearings that support the flywheels shaft are Oilite sleeve bearings and contain a lining metal which has microscopic pores to allow oil to penetrate through it to create an oil wedge between the shaft and bearing lining. The bolts used to add unbalanced mass to the flywheel each weigh 0.0167 pounds.