C. Wierre et al., FINITE-ELEMENT ANALYSIS OF THE INITIAL-STAGE OF THE INDENTATION ROTATION TEST FOR PHOSPHATE AND STEARATE COATINGS, Journal of materials processing technology, 41(2), 1994, pp. 171-185
Well fitted to determine the behaviour and seizure of thin coatings, t
he test involves a rotating cylindrical specimen on which a small prof
iled indentor exerts a non-uniform normal pressure. The normal load re
mains constant as the time of rotation increases. The friction-force v
alues are related to the behaviour of the coatings and when the interf
ace become damaged generally, the friction force increases strongly. T
he rotating time required for these observations is related to the ini
tial stress and strain distribution in the vicinity of the contact sur
face when the normal load is applied on the indenter, the specimen bei
ng motionless. For this indentation phase, the distributions of stress
and strain are obtained by means of a refined localised finite-elemen
t model which takes into account the mean thickness and the mechanical
properties of a typical zinc-phosphate coating first, and then of a t
ypical bi-layered zinc-phosphate and zinc-stearate coating second. It
is found that the slider-specimen contact area and the stress and stra
in maps in the contact vicinity change significantly from the virgin s
teel specimens to the bi-layered specimens. The effective stress decre
ases whilst the effective strain increases, the strain maps being more
perturbed by the coatings than the stress map. Particular attention i
s focused on the local shear stress which is related to the performanc
e of the adhesion coating.