Combating rebound of objects

[desertgarage]

I'm trying to deal with the rebounding action(bounce) of two flat faced steel cylinders striking each other. I'm convincing myself that re-configuring from two flat faces to a 25-30 degree off center line conically tapered end on one cylinder and a corresponding angle female feature on the other will redirect the impact forces and greatly reduce the bounce. Not enough angle to taper lock, but a redirecting of energy as opposed to the 90 degree faces. Does this theory have any validity?

 

[drawoh]

What sort of a student are you? We have a forum for students to post in.

If two steel objects collide, the kinetic energy is converted hopefully to elastic deformation. The elastic deformation then converts back to kinetic energy. Any deformation other than elastic is what we engineering type call damage, and your parts spring back a lot less, or not at all.

Angling your faces will cause your parts to bounce in some direction other than straight back. Are you guiding your parts somehow?

Can you apply a damping material like rubber or one or both contact faces?

 

[dvd]

what do the opposite ends look like? the initial wave due to impact propagates to opposite end and reflects back to the striking face. you may have some luck by modifying the opposite face to modify the reflected wave.

 

[desertgarage]

Thank you for the reply. I am a JC student completing prerequisites in hopes of entering MIT. End goal is a career in design of mechanical assemblies. I was hoping to gain guidance from "teacher" types. If this is inappropriate use of the forum please let me know.
I have a very basic understanding of how the "bounce" is induced. The deformation, though slight in the case of my steel members, resulting in kinetic energy opposite the deformation and thus the rebound (bounce). I'm surmising, but having trouble concluding, that two conical surfaces interfacing would change the direction of the deformation and corresponding kinetic energy ultimately reducing the bounce substantially.

 

[dgeesaman]

Can you fill one with loose material like a dead-blow mallet?

 

[desertgarage]

Can you fill one with loose material like a dead-blow mallet?

Yes, I could. This is more of a dilemma of trying to resolve my reaction theory of the conical interface vs. the flat interface in my mind. I don't have a specific assembly I'm currently trying to address, but the conditions arose in my mind and I feel there must be an engineering answer as opposed to constructing physical prototypes to find out. A dead blow effect I easily can see would address the issue, but would the conical interfaces require even less dead blow mass to have the same end result?

 

[dgeesaman]

I don't know to be honest, but maybe adding an o-ring to one of the surfaces will trap air and further cushion the impact.

I think that if there is any difference, the alignment of the colliding parts and precision of the surfaces will govern the behavior.

 

[IRstuff]

Maybe something could be taken from a dashpot design
https://en.wikipedia.org/wiki/Dashpot

 

[desertgarage]

Maybe something could be taken from a dashpot design
https://en.wikipedia.org/wiki/Dashpot

Yes, It could and thanks for the reply. This is currently more of a dilemma of trying to resolve my reaction theory of the conical interface vs. the flat interface in my mind for future reference. I don't have a specific assembly I'm currently trying to address, but the 2 conditions arose in my mind and I feel there must be an engineering answer as opposed to constructing physical prototypes to find out.

 

[dvd]

A conical interface will never be perfect, so either (most likely) you hit at the bottom, or at a ring somewhere above that. I think that a ring interference somewhere above the bottom would be best because there would be some energy absorption as the male cone feature forced into the female cone feature.

 

[IRstuff]

This is currently more of a dilemma of trying to resolve my reaction theory of the conical interface vs. the flat interface in my mind for future reference.

Not sure there's much to resolve; striking at an angle means the reaction is forced into horizontal vs vertical components, which may, or may not, be appropriate to your system. If this were some sort of piston, then the horizontal components would cause radial reactions in the piston, which might damage the structure, like bearing sleeves, etc., since the system is designed for axial forces and loads. In dvd's drawing, that would result in scuffing of the conical surfaces and edges, which could result future impacts creating even more damage, and possibly leading to jamming, etc. Energy and momentum must always be conserved, so they have to go somewhere.

 

[dvd]

Have a read on this product and perhaps you can implement some aspect in your design -

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