However, when conducting the nanoindentation test in the liquid, the indenter will inevitably bear the flotage, and this will result in the inaccurate collection of reaction force about the indenter.
This paper focuses on the quantitative influence of flotage on the elastic-plastic indentation mechanical properties of a cortical bone specimen.
Assuming that the bone specimen itself will not be influenced by the flotage, only the indenter will bear flotage during the whole experiment process.
Moreover, the flotage applied to the indenter will increase along with the increase of immersion depth h; thus, the measured immersion depth h can be classified into two different conditions; namely, [h.sub.flo] [less than or equal to] [h.sub.ind] and [h.sub.flo] > [h.sub.ind].
Assuming that the fluid keeps relatively static in the whole indentation process and the liquid media's surface tension adhered to the indenter can be neglected, thus the indenter will only bear the flotage in liquid media.
Regarding the Berkovich indenter, when the submergence depth [h.sub.flo] is smaller than the tip height of indenter [h.sub.ind], namely, [h.sub.flo] [less than or equal to] [h.sub.ind], the formula of flotage can be written as follows:
Here, [P.sub.flo] is the flotage applied to the indenter, [rho] is the density of liquid media, g is the ratio of gravity and mass, and h is the measured immersion depth.
Similarly, the flotage applied to other spherical indenter and cubic indenter can be deduced by using trigonometric functions and Archimedes flotage principle.
On the other hand, when the condition is [h.sub.flo] > [h.sub.ind], the formula of flotage can be written as