Measuring Forces between Spheres: Dependence on Sliding Speed
Cheng-En Tsai1*, JC Tsai1
1Institute of Physics, Academia Sinica, Taipei, Taiwan
* Presenter:Cheng-En Tsai,
In this talk, I will introduce a homemade system, designed for measuring the vectorial force response when two soft particles are rubbing against each other. Here, we focus on the Polydimethylsiloxane(PDMS) particles we made from molding. We find that the tangential force is rate-dependent: the force drops substantially as the rubbing speed goes beyond certain threshold value. On the other hand, the normal force appears insensitive to the driving speed.
These findings support the explanation we have made for the stick-slip transition we observe in our previous granular fluid experiments, which will be summarized briefly.

Keywords: measuring the vectorial force, soft particles