# 1D element spring as real springs

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Hi,

I'm new to hypermesh and I have a simple question for you guys. Can we use a spring element to act like a real coil spring? In fact, I got an impactor hitting a dummy and in the real experiment, the impactor is stopped at a certain distance from it's initial position by a coil spring. I wanted to use a imposed displacement, but I need to keep the initial velocity to allow the impactor to slow down by transferring its energy to the dummy. So, I thought that maybe I can stop the impactor (which is rigidbody) by a spring element like it is in real experiment. Can I do that? Or is there something else I could do? So far, I wasn't able to use the spring correctly.

Thank you very much!

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Hi JM,

You can actually define a time history curve which defines the imposed displacement and attach it to the master node of the RBODY ( Impactor)

The time history curve can be defined in a such a way that, it is impacted with certain displacement to begin with and the displacement dies down to zero.

For example:

X (time)    Y(Imposed Displacement)

0.0             0.0

0.1             1.0

0.2             3.0

0.3             0.0

Above, the hammer moves a distance of 3mm at 0.2sec  and comes to it's original position at time 0.3sec.

If you want to connect the Hammer with a spring and control the motion, then you can actually define a load vs displacement curve similar to the above with /PROP/SPRING property card

Let us know if this helps!

Thanks,

Vikas

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Hi Vikas,

I thought using this option, but I really need to lauch my hammer at a certain velocity (initial velocity). Therefore, I don't want to impose a displacement to the hammer. I only want to stop it by using a coil spring. But, maybe I can define a component which would be a coil spring and add a interface between the 1D coil spring and my 3D impactor? The coil spring would be at a certain distance from the initial position of the hammer. So the hammer will impact my dummy and be stopped after the impact at a certain distance.

I don't know if I'm clear or not, but thanks for your response!

JM

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Hi JM,

Yes, in case you don't want to impose a velocity to control the hammer as i suggested above you can attach few springs to the nodes of the hammer and define the load vs displacement curve to the spring element using /PROP/SPRING card.

Let us know how it goes!

Thanks

Vikas

Rahul R likes this

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Thanks it's working!

Rahul R likes this

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