Bearing strength and failure behaviour of composite pre-tightened multi-tooth joint

Abstract

The bearing strength and failure behaviour of a new composite pre-tightened multi-tooth joint was studied experimentally and numerically. Four groups of different types of specimens were fabricated by varying key design variables including the pre-tightening force, tooth depth, tooth length, and number of teeth. Axial tensile tests were performed to determine the bearing capacity, failure modes, and load distribution law of the specimens. Furthermore, a three-dimensional continuum damage mechanics (CDM) model was established based on the Pinho theory and nonlinear shear constitutive model. Finally, the corresponding numerical results were compared with the experimental results and demonstrated good agreement. The results indicated that in a certain range, the bearing capacity of the joints increased with an increase in the pre-tightening force, tooth depth, tooth length, and number of teeth. The designed multi-tooth joint has four typical failure modes: crushing failure, shear failure, longitudinal splitting failure, and fibre breakage. The load distribution ratio of each tooth of the joint is non-uniform, and it is significantly affected by the number of teeth and failure mode. The comparisons among the experimental and numerical results indicated that the CDM model is effective for predicting the bearing strength and failure behaviour of the multi-tooth joints.