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Adams HW 5

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F11Jonathan

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Unread post Mon Oct 24, 2011 12:08 pm

Adams HW 5

For Question 2, is this asking for an analytical calculation, or a value calculated from a measured max min in the simulation? If it is from the simulation, can we still use the flexible valve or do we need to revert to the stiff valve? Is there a way to go back to the stiff valve without starting again from the beginning?
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TobyH

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Unread post Mon Oct 24, 2011 4:14 pm

Re: Adams HW 5

The curve-on-curve constraint is only used with the rigid valve, so assume the question refers to that. I don't think you can go back to rigid unless you clicked a checkbox to save the original body when you created the flex-body from the rigid body. The curve-on-curve constraint with rigid valve is close to the beginning, so it is easy to start over.

You should know what to expect for the displacement of the rigid valve with curve-on-curve constraint based on how the motion was defined/created. However, you should measure in the simulation and include a plot to verify.
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F11Gratz

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Unread post Mon Oct 24, 2011 8:08 pm

Re: Adams HW 5

After adding the contact force (before adding the spring), running the simulation causes the the valve and the cam follower to decouple from the link and launch off into space. I can't find any directions that I missed or anything, so can someone tell me whether or not this is supposed to occur? I would just assume that it's wrong, but the directions sort of sound like this step isn't supposed to work anyway.
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TobyH

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Unread post Mon Oct 24, 2011 10:03 pm

Re: Adams HW 5

F11Gratz wrote:After adding the contact force (before adding the spring), running the simulation causes the the valve and the cam follower to decouple from the link and launch off into space. I can't find any directions that I missed or anything, so can someone tell me whether or not this is supposed to occur? I would just assume that it's wrong, but the directions sort of sound like this step isn't supposed to work anyway.


This will happen. The spring will keep things in place once you add it.
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F11Carrie

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Unread post Tue Oct 25, 2011 9:58 am

Re: Adams HW 5

Is there a strict definition for "no lift-off?" Is there a way to measure the separation between the rod.circle and cam, or is it just a visual inspection of the simulation? The only other thing I can think of is that the contact force should remain non-zero?
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F11Jonathan

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Unread post Tue Oct 25, 2011 10:23 am

Re: Adams HW 5

If you watch the contact force you can tell if there is liftoff. If the force is zero liftoff occurred.
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F11Graham

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Unread post Wed Oct 26, 2011 6:11 pm

Re: Adams HW 5

When I add the spline it just adds a spiral instead of the cam profile. How do I force it to make the cam profile?
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TobyH

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Unread post Wed Oct 26, 2011 8:35 pm

Re: Adams HW 5

F11Graham wrote:When I add the spline it just adds a spiral instead of the cam profile. How do I force it to make the cam profile?


So it draws a profile, but instead of a closed loop, it makes a spiral? If so, then it sounds like the translational motion you applied to the valve might be wrong. Double check that the valve moves as specified.

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