Timeline for Modelling an inelastic, rough, constrained collision
Current License: CC BY-SA 4.0
9 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Jul 27, 2020 at 21:34 | comment | added | Kotlopou | I am not, but assuming that the answer can be stated in vector form (if not derived), I can at least test if it works within the simulator I am using for this. | |
| Jul 27, 2020 at 20:34 | comment | added | jalex | Are you at all familiar with screw theory in robotics, and/or 6 dimensional velocities and forces. I have a solution for you, which you cannot arrive at with vector calculus (even for planar cases) unless you adopt the coincide notation afforded by screw theory. I have a short intro as an answer here FYI. | |
| Jul 27, 2020 at 18:38 | comment | added | Kotlopou | Perhaps the misunderstanding is that I am not looking for resulting velocities given the impulses and constraints. I am trying to reshape the collision models dependent on coefficients of restitution to a situation where they are also affected by the constraint impulses. This is what I tried to emphasise with the collision in the normal direction only (smooth) having "effective $c_T$" not equal to $1$. | |
| Jul 27, 2020 at 18:29 | comment | added | Kotlopou | I do see your point, and it is made explicitly in one of the sources (where $c_T$ is found as a function of the impact parameters, with a maximal value given by the material). But it is not the point here, as I look for the general case. | |
| Jul 27, 2020 at 18:27 | comment | added | jalex | @Kotlopou so you are assuming the two impulses are completely independent of each other, and I am saying that this is not the case, as the tangential impulse magnitude cannot exceed available traction. An if think a complete reversal is needed tangentially then $$ J_t = 2 \tfrac{1}{ m_1^{-1} + m_2^{-1}} v_{\rm slip} $$ | |
| Jul 27, 2020 at 14:39 | comment | added | jalex | Speaking of resources you need to read Notes 1 and Notes 2 on the canonical way of treating 3D body simulations with contacts, but unconstrained. | |
| Jul 26, 2020 at 18:37 | comment | added | Kotlopou | I will add links to resources I used for these contact mechanics into the question. | |
| Jul 26, 2020 at 18:34 | comment | added | Kotlopou | The main problem with this answer is that no slip is not what happens at perfect roughness. A perfectly rough collision actually reverses "slip velocity" at the contact point (which is the only way to conserve energy). I understand that there are two kinds of collisions - frictional and broken contacts. Frictional behaviour is determined by both surfaces, but broken behaviour is defined by the materials that temporarily store elastic energy. Overall, the problem is finding the impulses; the rest is just a lot of math. | |
| Jul 24, 2020 at 13:12 | history | answered | jalex | CC BY-SA 4.0 |