MBD Simulation on a Piston Assembly

In this project the analysis of the reciprocating motion of the piston is studied for various positions of the wrist pin axis with respect to the axis of rotation of the crank. The offset between these axis is made positive or negative and Linear displacement of the Piston Head is studied.

Modeling of all the parts.

1. Wrist pin

2. Piston

3. Connecting rod End cap

4. Crank

5. Connecting rod

Assembled model

The motion analysis is carried out in three different conditions,

Wrist Pin Offset - The position of the wrist pin is going to be varied as followed. But the center of the axis of the piston head and the crank are coincident to each other (i.e) They are on the same plane in all the three cases.For the second and third case the piston circle position is made offset 10mm positive and negative respectively.

\"0\" mm Offset -If the crank rotation is in the Clockwise direction.

Obtained the Linear displacement of the Piston Head

10 mm Positive Offset - If the crank rotation is in the Clockwise direction.

Obtained the Linear displacement of the Piston Head

10 mm Negative Offset - If the crank rotation is in the Clockwise direction.

Obtained the Linear displacement of the Piston Head

Superimposed all the three graphs into a single graph.

Observation:

• The amplitude varies for different cases.
• Offsetting 10mm negative will make the crankshaft to put extra force to pull the piston from TDC to BDC.
• The point in making offset is to increase the maximum displacement and angular velocity to be high in all cases.
• Stresses will be developed in wrist pin by offsetting

Animation of motion analysis