Efficient finite element modeling of the mechanical response of stranded ropes under large deformation

This work presents an efficient finite element model for simulating the mechanical behavior of synthetic stranded sub-ropes under large deformation. The model first simulates the shape of the sub-rope obtained starting from straight strands, then the sub-rope’s response to a tensile loading. The model represents the volume of the strands and takes into account the contact and friction between strands. A detailed 3D model representing four lay-lengths is first developed, to serve as a reference for validating a more efficient reduced model. The influence of the stresses generated when the strands are twisted into a helix to form the sub-rope is demonstrated. To reduce computational cost, a simplified model using periodic and symmetry conditions over one quarter of a lay-length is proposed. This reduced model shows excellent agreement with the reference model, both in terms of global response (force, torque and elongation) and mechanical fields. It also enables a very significant reduction in computation time. The reduced model is therefore particularly well-suited for parametric studies (typically construction parameters). The model allows for the rapid calculation of the global response of the sub-rope and the intra-strand and inter-strand mechanical fields.