Ploughing friction

Lafaye 2006 TribologyLetters

1. scratching of a rigid perfectly plastic material
2. 1958 Sabey [5] proposed taking into account a lost energy ratio b

I would probably start with this ref

3. 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.
4. this article uses this assumption directly, which is kind of strange.
5. this leads to the "model for a conical tip with a blunted spherical extremity" with assumption #4 and elastic recovery 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.

Carreon 2018 TribologyInternational

1. 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.
2. The ductile-to-brittle transition depth, , may also contribute to this behavior by causing ω to be a function of penetration depth, .
3. overall the PAVER model takes 1 more parameter into account, which is the ductile-brittle transition depth, .

Chamani 2016 TI

1. berkovch, nanoscratch, FEM,
2. , is the COF in the simulation.
3. ff(60) has the biggest as it has a maximum pile up.
4. the result is based on FEA, so the only conclusion you can use is that the pile up affects the COF heavily.