If you know the mass, centre of gravity of the pendulum and the angular displacement of the pendulum after impact you can calculate its velocity.īy knowing the centre of gravity and the angular displacement you can calculate the vertical shift in the centre of gravity of the pendulum as it swings this then can be related to its potential energy of mgh assuming no loss of energy thenĪlternatively it is very hard to calculate what the velocity might be without a lot more information like moment of inertia of the pendulum, friction in pendulum bearings, coefficient of restitution etc. RE: Wedge impacting on pendulum desertfox (Mechanical) 5 Oct 09 08:31 The collision is elastic, it happens 10^10 times in the life of the machine without failure.

That means I need the initial launch velocity, nothing else. I am trying to predict its motion after the collision. The small cam is constrained as described and does bounce off the large cam. The sphere is a small light steel object and the wedge is a hard plastic surface on a large heavy steel object. I am not happy with my equation for the collision which is why I asked the question on Eng-Tipsįor your info, the bodies are actually two cams. Thanks for your inputs but I am staying with my own estimate until someone provides a better equation. Impulse forces, duration of collision are indeterminate and irrelevant.Ĭollision between free-bodies is trivial but add in constraints and the solution is not at all clear. I saw the problem as a collision between objects. The sphere does leave the wedge, I have high speed video to prove it. Reminder: I am trying to determine the initial horizontal velocity of the sphere. RE: Wedge impacting on pendulum mikeJW (Mechanical)

Moreover, the OP can experiment with this and come to his own conclusion as to the validity of this estimate. I don't expect a 100% accurate answer, but I think it is a reasonable first approach and making it more complicated at this stage will serve no useful purpose and NO answers will be forthcoming. If the OP has a problem with that assumption, he could give more materials data. So I am assuming that the wedge and the ball are reasonably solid and elastic. Also,assumed a normal force to the wedge surface, which implies the absence of friction, a valid assumption here. While,you are technically correct, I believe for the problem at hand, a first cut conservative approach, the one presented, assumes an elastic collision (and therefore no crushing KE absorption). Wow.My goodness,you are looking for wave equations and friction induced shear forces, etc, etc, and energy absorption modelling? How do you plan on solving this problem? I good PHD problem?

Falling plastic wedge leaf springs