Vibration

SM3: Vibration

Discussion:
-The difference between measured vibration signal and the signal generator output;
Our output data has half that of the values of the actual frequency because of theway that the frequency counters is set up. This is an easily solved problem as we can simply double the data to obtain the according frequency.
-Levels of vibration for the exciter located at nodesand antinodes;
This experiment was conducted be positioning our exciter at a point on a metal bar. To keep the experiment fair we kept the exciter in the same position throughout all modes(at oneend of the bar). Using grains of sand it was easy to identify the nodes as the stationary points did not move the tiny grains and clear lines were formed. Using this information it is also easy to findpoints of maximum displacement (anti nodes).
However we found that if the exciter was moved there was a variation in amplitude. When the exciter was placed where, corresponding to a certainfrequency, there would have originally been a node we found that there were no oscillations at all. This is because the exciter was placed a factor of half a wavelength away from where the bar was securedonto a base. So when the wave was reflected it was totally out of phase with the waves being created by the oscillator.
We also found that while the exciter was placed at node and there was nooscillation, if it was positioned below an anti node maximum amplitude was obtained. This has a similar explanation. This time though the two waves are completely in phase and the wavelengths are added. Thisis called summation and so the total amplitude is two times the original.
-Errors;
However accurately we measure things, experiments will never be, error-free. In this experiment there are lots ofpossible errors that could have occurred:
-Human errors; Maybe the most important as it has no consistency, there is no plus or minus, just the chance that something may be misread or misused. For...