Dear Community,
I am looking for an article that contains experimentally determined coefficients of restitution for specific material pairings.
These must be impacts between spheres and plates, whereby the spheres must be made of a (highly) plastic metal such as aluminium or lead. For the plates, a certain comparison is important to me. On the one hand, the experiments must have been carried out on hard/ elastic plates (e.g. made of glass or steel) and on the other hand on soft/ damping plates (e.g. plastics such as acrylic glass).
The impact velocity should be in the low to medium range.
Unfortunately, I have not yet found such an article. I would be very grateful for any help.
With best regards
Ronny
Calibrating the Digital Twin of a Laboratory Ball Mill for ...
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by B Doroszuk · 2024 — The final parameters for simulation balls were coefficient of restitution = 0.390 and coefficient of kinetic friction = 0.496. In total, 13 iterations resulting ...
@ Suresh Ahuja
Many thanks for your efforts!
Unfortunately, the article you provided does not help me any further, as it only gives coefficients of restitution for ONE specific material pairing.
The decisive factor for me, however, is that the plate material is made of TWO different materials: hard (e.g. chrome steel or glass) and soft/damping (e.g. plastic such as acrylic glass). Impact tests must therefore be available that were carried out once on hard plates and once on soft damping plates.
In addition, several series of measurements (coefficient of restitution as a function of impact velocity) would be much more advantageous.
With best regards
Ronny
Article Experimental Investigations on the Coefficient of Restitutio...
It's not explicitly the comparison you are asking for, but contains a lot of experimental data for the COF in low-velocity elasto-plastic sphere-on-plate impacts.
I do not have an answer to the literature here, but I have seen data on this indicating that there will be a hardening effect, even if the spheres are dropped on steel.
I can mention one source Falcon et al (french) who dropped a tungsten sphere on a hard surface.
@ Emanuel Willert
Thank you for the article!
As you wrote in a similar vein, it unfortunately doesn't contain the comparisons of impact processes that really help me. Nevertheless, the article does contain a lot of interesting results.
With best regards
Ronny
@ Anders Buen
Thank you for your answer!
However, the hardening effect is not the focus of my interest here. The impact of a tungsten sphere, which tends to exhibit low plasticity, is also unsuitable for my investigation.
Ultimately, I am interested in the extent to which viscous damping or viscoelasticity can attenuate/‘dampen’ the plastic process.
In our research group, we had already carried out experiments with aluminium spheres on glass plates, but unfortunately not on acrylic glass plates.
It is now interesting to me whether a damping/‘soft’ plate weakens/reduces the plasticity to such an extent that the coefficient of restitution is even greater than in the experiments on the glass plates.
These results would help me to analyse other impact processes.
With best regards
Ronny
The coefficient of restitution is dependent on the vibration shapes of a plate. You will get a different answer dropping the sphere on the crossing nodal lines, than on the ore active areas of the plate.
You will have to take into account the hardening effect even if that is not the main issue, because it can affect the results.
Falcons article is particularly interesting because of the theory given there. I have used it for assessments of gym matting properties from video analyses in slow motion.
@ Anders Buen
Can you please provide a link to the article by Falcon et al. here?
The hardening effect may be relevant or interesting for my further analyses.
Thank you very much!
Greetings
Ronny
Ronny Böttcher Falcon, et al: Behavior of an inelastic ball bouncing repeatedly off the ground, The European Physics Journal B, 3, 1998, pp 45-57.
Article Bouncing of one elastic ball bouncing repeatedly off the ground
@ Anders Buen
Thank you for the article!
I've taken a closer look at it.
Unfortunately, as I feared, the article doesn't really help me any further. It also contains some weaknesses - for example in the evaluation of the measurements (CoR), which are ultimately interpreted exclusively with a viscoelastic model. For example, the importance of the bending wave (Zener) - although relevant here - is underestimated and adhesion is not included in the analysis at all.
With best regards
Ronny
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