Effect of indenter tip radius on the load deflection behavior of thin plates

Abstract

ABSTRACTwThe effect of indenter radius on the loaddeflection behavior of a clamped, thin isotropic and homogeneous plate is discussed. A depth-sensing nanoindenter 75 was used to apply a transverse load to the plate center and measure the corresponding plate center deflections. The applied stress is assumed to be uniformly distributed over the contact area. This study shows that the central deflection of the plate is insensitive to small changes of indenter tip radius when the normalized indenter tip radius is smaller than about O. 10 (here, normalized indenter tip radius is defined as the ratio of the indenter tip radius to the plate radius). For these (a) small normalized indenter tip radii, the indenter radius effect is the same in both the small (linear) deflection range and in the large (nonlinear) deflection range, Blunt indenter tips help to minimize material nonlinearity in the region of contact due to localized plastic deformation and/or microcracks, allowing geometrically nonlinear deflection data to be obtained in a less ambiguous manner.