The conduction of the experiment of the slider crank chain Essay

Sample of Calculation
For table and graph of velocity against angle since all the 3 experiment starting with 45 mm/s, so conclude that we want starting the point with 0. Therefore, we come out with equation
X 45 = (new value of velocity (mm/s)
At first point 45 45 = 0 mm/s
Slope for piston velocity against angle at experiment 175 mm
There are two different slopes. First at 0o 70o, Second at 180o 270o. Therefore
1. (36 - 0)/(70 - 0) = 0.51
2. (-1 - (-36))/(270 - 180) = 0.39
Analysis and Discussion
In this experiment, from graph 1 and 2, we noticed that there are relationship between velocity and displacement versus the crank angle. Graph 1 shown that there are quadratic pattern while the graph 2 shown that there are sinusoidal pattern. However, both graph have same characteristic which the velocity and displacement will back to initial condition after one revolution.
There are different ratio of crank and connecting rod which effected by different length of connecting rod. From this different, we notice that higher the ratio will make lower the maximum point of displacement. So, that prove the theory from part of this experiment. The little different between three connecting rods because of something error like parallax error and operation error.
This experiment related with simple harmonic motion because of oscillating motion of the piston. From the graph 2, we noticed that there are maximum acceleration due to higher gradient of the graph. This is because of the increasing and decreasing of the velocity of the mechanism itself. So, we assume that the higher value of ratio give a better pattern of graph and form of simple harmonic motion of graph.
From this fact, we found that the gradient is higher at 0-70 and 280-360 than gradient at 70-280. So, the change of velocity and the acceleration will be highest in that two region. Finally, acceleration must be zero at the angle of the maximum velocity occurs.
CONCLUSION
As for conclusion, by doing the experiment of the slider crank chain, the characteristics of the mechanism is learned. Method of instantaneous centers is being used to obtain the graph of piston velocity versus crank angle, while assuming that the crank rotates at a constant angular velocity. From this experiment, we found that the highest velocity occurred at angle of 80o and 280o. We can see by both graph where the piston velocity graph showed a very similar shape for all set of crank ratio but the piston displacement showed that the highest ratio displacement was not relatively as high as a low crank ratio. This means that the 175mm connecting rod does not have to move as far as the 115mm connecting rod to achieve the same velocity. Finally, it is proved that the piston motion tends to approach simple harmonic motion with the increasing values of the corresponding rod and crank ratio.
REFERENCES
Manual lab MACHINE DESIGN & CAD LAB