  In this work we present a novel computational method for embedding arbitrary
curved one-dimensional (1D) fibers into three-dimensional (3D) solid volumes,
as e.g. in fiber-reinforced materials. The fibers are explicitly modeled with
highly efficient 1D geometrically exact beam finite elements, based on various
types of geometrically nonlinear beam theories. The surrounding solid volume is
modeled with 3D continuum (solid) elements. An embedded mortar-type approach is
employed to enforce the kinematic coupling constraints between the beam
elements and solid elements on non-matching meshes. This allows for very
flexible mesh generation and simple material modeling procedures in the solid,
since it can be discretized without having to capture for the reinforcements,
while still being able to account for complex nonlinear effects due to the
embedded fibers. Several numerical examples demonstrate the consistency,
robustness and accuracy of the proposed method, as well as its applicability to
rather complex fiber-reinforced structures of practical relevance.
