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Second derivative of displacement singularity problem

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jonas.neuhaus
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Second derivative of displacement singularity problem

Hi,

I am currently analyzing the results of a drop test (Aluminum casing on Aluminum plate) and some of the acceleration results do not seem to add up. The results above 1m drop height (4.43m/s impact velocity) seem to be consistent. This however changes dramatically between 1,98 and 3,43 m/s (>0.2m height) impact velocity. The data seems to show a kind of singularity at around 0,00056s (note that the impact itself is at 0,00026s).

Using origin, i added the given XYZ-accelerations (absolute values). This does not show beforementioned behavior.

What could be the problem?

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AstroJohnPE
in reply to: jonas.neuhaus

 

Hi Jonas,

 

If the spike occurred over 1 or 2 time steps, then I would be suspicious. But there are about a dozen time steps in the spike, so I would tend to believe it. I think you need to look at node 6680 and step through the time steps to see what it is doing. Localized deformation may be causing it to accelerate while other parts have a lower acceleration.

 

 

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