# Inelastic Collision Question

• alext918

#### alext918

Does anyone know of any inelastic impact / collision equations or theories that somehow incorporate a spring constant or Modulus of Elasticity?

I have a problem where I need to show how changing a different material (ie. a different Elasticity) will affect the velocity after impact.

The masses are known, and one object is moving at 2 m/s right before impact and hits a stationary object.

Thank you

I don't know of any such equation - but would also be interested if one exists.
The reason I doubt the existence of such a formula is that if the Modulus of Elasticity is important in the impact, it is an elastic collision. Or, perhaps putting it a little differently; if the collision is inelastic, then the Elastic Modulus is not going to be very helpful.
For the collision to be inelastic, you need to deform the material beyond its yield point. Beyond this point the Elastic Modulus is not much use.
It is very difficult, I imagine, to meaningfully quantify the behaviour of a material in a collision when it deforms.
As I say, if there is a mathematical treatment, I would also be interested. (And surprised if it could predict the velocities after impact)

So I've found that using modulation and simulation techniques and using the program Simulink can model my problem accurately.

The issue now is that I am new to Simulink and unfamiliar with the program. I must model a 2 body collision in Simulink. Physically, I have an object hitting another object, which both in turn hit a third object.

Does anyone have or know of any premade elements to model a linear (axial), 2 mass collision? I want to couple 2 of these 2 mass collisions to model my problem. Any help is apprceiated.

Thank you!