ENGIN2303 – 202020 Page 1 of 1 ENGIN2303 – Mechanism and Machine theory Assignment 3 – Design task (25% of the course mark) Due: Week 11 The crank in the mechanism shown below rotates in the...

Mechanism and Machine theory


ENGIN2303 – 202020 Page 1 of 1 ENGIN2303 – Mechanism and Machine theory Assignment 3 – Design task (25% of the course mark) Due: Week 11 The crank in the mechanism shown below rotates in the counter-clockwise (ccw) direction with an angular speed of 150 ??????. The length of the crank is ??; the value of ?? is of your choice within the range 200 ≤ ?? ≤ 500 ????. The 0.52 ???? piston (link 6) of diameter 120????, attached to one end of link 5, pushes against a pressure head of 7.2 ??. The power stroke of the piston is along the negative (−????) direction of the y axis as shown in the figure. Consider all other links are massless. Design links 3, 4, and 5, and the distances ??4?? and ??4?? so that the motion of link 6 fulfils the conditions set out by yourself. Describe the conditions that you decided to set and briefly explain them. Note that the lengths of links 3, 4 and 5 don’t have to be in proportion with the length of link 2. You are required to perform the following analysis in your report: 1. Animate the linkage on both Linkage and Matlab 2. Plot the path of the mid-point of link 3 using Matlab 3. Plot a graph showing how the transmission angles vary with the crank angle. Note the maximum and minimum values of these transmission angles. Is this an ideal mechanism to perform this task based on the conditions set out by yourself? If it is not then what are the changes you propose? Is there a better approach (a better mechanism) to perform this task? 4. Perform the velocity and acceleration analysis for the mechanism. Graph the velocities and accelerations of various links (3, 4, 5, and 6) against the crank angle. 5. Graph the velocity and acceleration of the mid-point of link 3 against the crank angle. 6. Use the virtual work method to calculate the crank torque, ??, as a function of the crank angle, ??. Plot the ?? − ?? diagram of the crank. 7. Design a flywheel for this system such that the speed fluctuation is not to exceed 5% of the crank speed. What's the power of the motor needed to drive the mechanism? 8. For suitable pin diameters and a coefficient of friction of 0.15, estimate the energy lost at pins ??,??,??, ?? and ??4 in every cycle. Submit a PDF or Word file of a neatly typed assignment in a report format with calculations, illustrations, and graphs. Matlab files and Linkage files to be included in a zip file. Include all references. --- The end --- 6 power stroke ??