| Slip-critical connections have been used in steel structures for a long time where bolted joints are subjected to cyclic load and fatigue with slotted or oversized holes. The understanding of these connections has resulted in the limitation of maximum slip coefficients (0.50 for Class B surfaces) with surface preparation. High performance surface coating (HPSC) is one possible new method to significantly enhance the strength of slip-critical connections. In this research, two kinds of mineral particles, synthetic diamond and tungsten carbide are applied on HPSC for simple shear slip tests with variation in parameters of particle size, particle density, slip rate and clamping force. Finite element simulations are conducted for sensitivity analysis of the research. The test results showed that HPSCs can give drastically enhancement in slip coefficient and provide more stable, predictable behavior than bare metal surfaces, one group of HPSCs can give slip coefficient as high as 0.52 +/- 0.01, particle grain size and particle density will affect the slip coefficient of HPSCs, slip rate and clamping force will not affect the slip coefficient of HPSCs. Simulation results showed that considering HPSCs as homogeneous and isotropic material can well predict the slip coefficient and slip load of the connection, but not suitable for the behavior after failure. Recommendations are made for continue research on HPSCs. |
