Ploughing friction

2020-08-18 本文已影响0人边路乙拉

Lafaye 2006 TribologyLetters

I would probably start with this ref

A model that takes into account the elastic recovery defined by a rear angle x as shown in figure 1, was proposed by Bucaille et al. [6] and further developed by Lafaye et al. [7] for a perfectly conical tip.
$\mu _{ploughing} = S_t/S_n$ this article uses this assumption directly, which is kind of strange.
this leads to the "model for a conical tip with a blunted spherical extremity" with assumption #4 and elastic recovery $\omega$ from #3. The result of this article shows that the increase of the COF during initial stage of a scratch is caused by the blunted spherical extremity.

Starts with Lafaye's work with the assumption of elastic recovery and a blunted spherical tip. Which requires three input parameters:
- nanoindenter half-angle θ,
- nanoindenter spherical tip radius R,
- elastic recovery parameter ω.
The ductile-to-brittle transition depth, $h_{DBT}$ , may also contribute to this behavior by causing ω to be a function of penetration depth, $ω = f(h)$ .
overall the PAVER model takes 1 more parameter into account, which is the ductile-brittle transition depth, $h_{DBT}$ .

berkovch, nanoscratch, FEM,
$\mu _{apparent}=\mu _p+ \mu _a=\mu _p +f(\mu _s)$ , $\mu _s$ is the COF in the simulation.
ff(60 $\degree$ ) has the biggest $\mu _p$ as it has a maximum pile up.
the result is based on FEA, so the only conclusion you can use is that the pile up affects the COF heavily.