MBD Simulation on a Piston Assembly

AIM: To design and assemble piston crank and perform motion analysis for it in 3 different cases(0,negative and positive offset respectively.)

Geometry modelling -

piston-

gudgeon pin -

connecting rod

end cap-

Crank-

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Modelling simulation setup-

1)A motor at 2000 rpm is setup to the axis of the crank.

2) contact forces are established as follows-

i)crank-endcap

ii)crank-connecting rod

iii) connecting rod-gudgeon pin

iv) gudgeon pin-piston.

Material for all the parts is assigned as steel(dry).

Number of frames per second is set to 7200 in order to analyze each degree rotation.

Gravitational force is given in Y direction.

Hence forth the simulation is done for required results.

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Motion analysis for the piston crank at 2000 rpm and no offset-

The linear displacement of the piston in this case is 100mm(200-300)

*7200 frames*

Positive offset -

The observed linear displacement in this case was 100 mm as well(200-300) but initially starting at 250 then declining unlike the 0 offset graph where it was initially increasing.

negative offset-

The linear displacement in this case is 100mm as well but the initial point is even less than 250.

Superimposed graph of all three cases-

The graph indicates the linear displacement of the piston vs time in all three cases.

dark orange- 0 offset, orange-positive offset, green-negative offset.