Finite element solution of nonlinear intrinsic equations for curved composite beams

A geometrically nonlinear finite element analysis, based on a weak form of the geometrically exact intrinsic equilibrium and constitutive equations, is presented for initially curved and twisted composite beams. The resulting nonlinear equations are solved numerically for both nonlinear static deformation and linearized free vibration about the static state of deformation, Results are compared with published exact solutions for isotropic beams and with recently published experimental data for rotating isotropic and composite beams with swept tips. In both cases the correlation is excellent. Moreover, the correlation with the experimental data Is shown to be better than was achieved with a standard moderate deflection theory, illustrating that a geometrically exact approach Is needed for general purpose analysis of rotating beams.