Indentation of spherical shells by a rigid conical indenter is analyzed. Because the
shape change associated with overall bending provides a main deviation from
the corresponding indentation behavior of a half-space, finite deformation
analyses are carried out. The shell material is characterized by a hypoelastic
relation that reduces to isotropic linear elasticity for small strains and is an
elastic relation at finite strains for fixed principal directions. Axisymmetric
deformations are assumed. For indentation of shells there is a complex interaction
between the indentation response and the overall structural response of the
shell. The aim of the analyses is to give insight into the range of indentation
depths for which the indentation response dominates so that an indentation
analysis can be used to extract the elastic properties. Shells having various
thicknesses are analyzed. It is found that for spherical shells with thickness to
radius ratios less than or equal to 0.4 and for sufficiently shallow indentation
depths, the scaling of the indentation load with contact area has the same
form as that for indentation into a half-space but with a different scaling
constant.
Keywords
indentation, elasticity, spherical shells, finite element
modeling
Department of Materials Science and
Engineering
College of Engineering and Center for Advanced Scientific
Computing and Modeling (CASCaM)
University of North Texas
1155 Union Circle #305310
Denton, TX 76203-50175
United States