1D element spring as real springs

JM Desrosiers

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!

Altair Forum User

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

 

 

JM Desrosiers

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

Altair Forum User

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

JM Desrosiers

Thanks it's working!