Rigid Dynamics of Hand Pump Analysis

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  • Last Post 12 February 2019
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Ananth Narayan posted this 11 February 2019

Hello everyone,can you please guide me in finding out velocity and acceleration of bodies of hand pump model. I have tried in rigid dynamics but result do not come up. Also got error. If possible please attach video or image. Model Here

Regards Ananth Narayan

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peteroznewman posted this 11 February 2019

Hello Ananth,

I followed the link and downloaded the STP assembly file and open that in SpaceClaim. It looks perfect.

Where is your model?  Did you create any joints?  What Supports did you use?  What input motion did you define?  What errors did you get?

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Ananth Narayan posted this 12 February 2019

That was my model. Yes I created joints as per mechanism simulation. But when I give angular motion as joint load on link between plunger and handle and solve it doesn't solve. Also on last picture I get update error on solution

Regards Ananth Narayan

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jj77 posted this 12 February 2019

Trying this for fun Peter .

 

Never done this, but it seems that you only need the joints, not contacts as well - if both are defined it does not work, with joints only it is works.

peteroznewman posted this 12 February 2019

Hello Ananth,

Okay, good job on the geometry, I see you have assembled all the parts with joints. The problem with using a Moment load is you can put in a value that is so large compared with the mass of the parts that the accelerations are huge and you need millisecond time steps to see it move.

Instead of applying a Moment on a Revolute Joint, I applied a rotational velocity. Now I could safely use 1, 2 or 3 seconds depending on the number I put in for the rotational velocity. So if I have 1 rad/sec and I simulate for 1 second, it will rotate 1 radian.  Put that on the revolute between the long handle and the short link.

Regards, Peter

 

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Ananth Narayan posted this 12 February 2019

Thank you very much peter. But what does, time steps and other parameters mean under analysis setting.

 

Finally got answer and trick to simulate error free simulation.

 

Regards Ananth Narayan

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peteroznewman posted this 12 February 2019

Great. Step End Time is self explanatory. With Auto Time Stepping, you provide an Initial Time Step for it to start integrating. If that is too large, it will automatically cut back. The minimum time step is how small you will allow the integrator to go when it gets to a difficult part of the simulation. You don't have any. Maximum time step is how large you will allow the integrator to go when it get to an easy part of the simulation. You can force it to take smaller Maximum time steps to get a more uniform output of results.

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Ananth Narayan posted this 12 February 2019

Thank you so much for clarifying my doubt.

Regards Ananth Narayan

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