Third M.I.T. Conference on Computational Fluid and Solid Mechanics June 14–17, 2005  

Anisotropic pile-up pattern at spherical indentation into a fcc single crystal – finite element analysis versus experiment

B. Eidel*, F. Gruttmann
Technische Universität Darmstadt, IWMB, Petersenstraße 12, 64287 Darmstadt, Germany

  Full Text
In a recently performed indentation experiment of a ball into a [001]-oriented single-crystal sample of fcc-structure, the rim of the remaining indentation crater appeared as a square rather than as a circle. We present the results of a refined analysis, which aims to elucidate this curious new phenomenon and its physical origin. The methodology is threefold: (i) On the experimental side, measurements with a scanning electron microscope equipped with a backscatter electron detector are performed to reconstruct a 3D-surface model of the indentation topography. (ii) On the numerical side, we investigate this problem in a finite element simulation with a phenomenological material model for anisotropic elastoplasticity. (iii) A kinematical explanation for the observed deformation pattern is proposed that operates on the micromechanical scale of plastic slip in the fcc single crystal.

Keywords:  Computational inelasticity; Microindentation; Anisotropy; Constitutive modelling; Finite strains; Experimental validation

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