MBD Simulation on a Piston Assembly

REPORT ON MOTION ANALYSIS OF PLANETARY GEAR

AIM – To conduct the motion analysis of the Piston Assembly, generate and explain the plots for the given conditions.

BODY OF THE CONTECT

• CONDUCT MOTION ANALYSIS

• Parts of Assembly

The individual parts of the piston assembly are to be modelled first in order to model the assembly of the piston assembly.

Crank

Connecting rod and end

Gudgeon pin

Piston

• Assembly

Once all the components of the assembly are modelled then the next step to generate the complete assembly of those components. Here in solidworks it is done by assigning right mates to the components relative to their contact and sometimes as per the given conditions.

• Conduct the motion study

As the assembly of all component is completed with all the required constraints the motion analysis can be conducted which will eventually help to understand the behaviour of the system in the actual conditions.

Conditions of motion analysis

Input rotation speed = 2000 rpm

Offset to the wrist pin

Sr. No.	Wrist pin offset (mm)	Speed (rpm)
1	0	2000
2	10 (positive)	2000
3	10 (negative)	2000

As the input speed is of 2000 rpm which means rotation will have angular velocity of 12000 deg/sec hence in order to capture the linear displacement data per sec there is need to modify the value of frames per sec to 12000 frames per second and the precise contact option is also considered in the motion analysis.

• RESULT

• Linear displacement piston head without and with positive and negative offset

The above plot shows the Linear displacement in mm of the piston head with zero , 10 mm positive offset and 10 mm negative offset with respect to time. Here the results are shown for one complete rotation of the crankshaft. From the graph it can be clearly seen that there are three different time intervals at which the piston reaches to the bottom dead centre for three different cases. When we provide 10 mm negative piston pin offset then it is found that there is delay of few micro second to piston to reach to the B.D.C. and on the other if we see the graph for 10 mm positive piston pin offset then it is found that in this case the piston reaches few micro second early to the B.D.C.

CONCLUSION = From the entire challenge it can be concluded that motion analysis can be very close to accurate results for very minute change in the input parameters of the system.