Mixed-dimensional coupling method of box section member based on shear stress distribution pattern

The existing mixed-dimensional coupling method based on the energy conservation is commonly used. However, the assumption of shear stress distribution at the connected interface is relatively rough for the member with box section, which causes the stress near the connected interface to be discontinuous and causes a local stress concentration. The reliability of multi-scale model is in a low level. A simulation method of box section's shear stress distribution pattern is proposed to realize the mixed-dimensional coupling of box section member. A stress distribution calculation model is established to capture the real multipoint stresses at the connected interface firstly. Then the real stress distribution pattern is determined using the multipoint stresses and the surface fitting technology. Finally, the concurrent multi-scale model with high accuracy is established using the multipoint constraint equation. Three multi-scale models, cantilever beam with box section and beam-solid elements, were established respectively to validate the effectiveness of the proposed method, where these multi-scale models were based on the proposed method, one existing method and the CERIG method which is provided by ANSYS^®, respectively. Comparing with one existing method and CERIG method, the displacement and stress responses of the multi-scale model based on the proposed method were closer to those of the full solid element model. The proposed method can effectively improve the stress distortion near the connected interface, which can also ensure that the performance analysis of structural local detail be real and effective.