Engineering semulation - Essay Example

There are four tasks to be done: first is to show how to plot a specific behaviour of a system; the second task is about choosing the suitable time step for the simulation; in the third task I have to find the best spring stiffness, under certain speed and the last task is to describe the experience of using COSMOSMOTIONS and highlighting its advantages and disadvantages This sub-assembly has two rocker arms, two valves and a camshaft. It has to be analyzed. The least contact force between the rocker and the camshaft is to be found by varying (changing) the spring stiffness.

I deleted the lower parts of the complex system as seen in the picture. If it was included, the program will take too much time to calculate such a complex system. For task 1 to plot the contact force, linear velocity and linear acceleration charts, the motor speed was kept at 100 rpm. This is the linear velocity chart. The chart shows the rocker speed first rises up as the rocker rises and reaches a point where the speed becomes zero. Then speed starts decreasing while the rocker is retrieving its position.

This motion is periodic and is repeated continuously. Task two: controlling the accuracy in the simulation. The size of the time step is an important factor which affects the error in the simulation. Larger time step increases the error and a very small time step will cause the simulation program to take too much time to calculate; a suitable time step is to be chosen. The program has 98.7% probability that it’s accurate and the 2.3% probability is for a value between 317 and the first 42 value on the force chart.

I select the second accurate time step which is 0.00001 for the best efficiency and results in the minimum time. Choosing smaller time step will take more time to calculate, without any improvement in accuracy: Task 2 ends here. For task 3, I set motor speed to 7800 rpm and find