Abstract: The connection efficiency of composite pre-tightened multi-tooth joint is low because of uneven load distribution and single load transmission path. In this paper, based on the principle of bio-tooth (suture) structure, combining soft material with fractal, a composite pre-tightened multi-hierarchy tooth joint is proposed, and the bearing performance and failure process of the joint through experiments and finite element method under tensile load. First, the ultimate bearing capacity, load distribution ratio, and failure process of different hierarchies of teeth joints are studied through experiments. Then, the progressive damage models of different hierarchies of tooth joints are established, and experiments verify the validity of the finite element model. Finally, the effects of soft material and increasing tooth hierarchy on the failure process and bearing capacity of composite pre-tightened tooth joints are analyzed by the finite element method. The following conclusions can be drawn: (1) The embedding of soft materials changed the failure process of the joint. Increasing the tooth hierarchy can give the joint more load transfer paths, but the failure process of the joint is complicated. (2) Embedding soft materials and increasing the tooth hierarchy simultaneously can effectively improve the bearing capacity of composite pre-tightened tooth joints, which is 87.8% higher than that of traditional three-tooth joints.

Key words: Composite pre-tightened multi-hierarchy teeth joint, Tensile experiment, Finite element analysis, Failure process, Suture structure