Successive differentiations of
the rotation tensor are characterized by successive differential rotation vectors. Useful
expressions of the differential rotation vectors for differentiations up to third order
are derived. In the context of the exponential parameterization, explicit expressions
for the differential maps (the maps providing the differential rotation vectors from
the differentials of the parameters chosen) are obtained by resorting to an original
infinite family of recursive subexponential maps. Useful properties of the mapping
tensors are discussed.
The formulation is appropriate for nonlinear problems of computational solid
mechanics, when spatial, incremental, and virtual variations of particle orientations
must be dealt with together. As an application, the classical problem of
modeling space-curved slender beams by finite elements is considered. The
variational formulation and the nonlinear interpolation of the orientations,
together with the relevant linearizations, consistently exploit the proposed
differentiations and lead to an objective beam element. Two test cases are
discussed.