Deformation in static and transient case

[1Keenan]

Hi all,

I have a doubt that I would like to solve with oyu help.
Basically I want to calculate forces on a solenoid due to the magnetic field it produces and than calculate deformation.

I consider 2 cases:
1/ Static
I did analytic calculation for force calculation, and i made FEM simulation in the static case to calculate also the displacement.
Force value is numerically in agreement with analytic result and I trust diplacement magnitude as I'm not expert in mechanical stress. result is 35mm as maximum displacement

2/ Transient
Current pulse in the solenoid is 2nsec at FWHM and tails exted for something like 5nsec, so I implement transiet simulation.
Force maximum value is the same as in the static case, but displacement is much smaller (2mm)

Now it make sense to me that such fast and impulsive stress is not very efficient, but mine is just a feeling and I would like to understand if it is correct or not and why.

Thank you

 

[Nidum]

Please start again and tell us clearly what you at doing and why .

 

[1Keenan]

more in general I want to understand if it is true or not that an impulsive force, something a Delta impulse in time, is not able to deform a body as if the same stress act for a long time.

 

[Chestermiller]

Don't you think that applying a force continuously would give a larger displacement than applying a force and then almost immediately removing it?

 

[1Keenan]

Yes, this is what I think and why I said I have the feeling sounds logical, but I would like to have some reference I can read on this topic