Experimental and numerical study on the cyclic performance of the gear-bolt semi-rigid joint under uniaxial bending for free-form lattice shells

To study the cyclic behaviour of a novel gear-bolt semi-rigid joint, quasi-static tests were conducted on seven full-size specimens. The key parameters of the gear-bolt joint investigated in this test include the gear-bolt diameter, number of teeth, and tooth depth to gear-bolt diameter ratio (t/d). A detailed research is carried out to study the effects of these parameters on the hysteresis curves, skeleton curves, degraded characteristics, ultimate capacity, energy-dissipation capacity, and failure mode. The experimental results showed that the hysteresis performance was enhanced with the increasing of number of teeth, gear-bolt diameter, and t/d. In particular, the hysteresis curves were fuller with higher number of teeth; however, an excessive number of teeth should be avoided as it would lead to a brittle rupture of the teeth. The ultimate capacity increased with the increase in the gear-bolt diameter and t/d. of accurate finite-element (FE) models of gear-bolt joint considered the geometry and material nonlinearity was established, and the accuracy of the FE mode was verified by comparison of the computation with test results.