Abstract:Considering the characteristics of residential buildings in western China, a hybrid joint with "wood on top and steel at the bottom" was proposed, with the drop hammer impact force serving as an important basis for structural design. Based on the principle of energy conservation and using the impact vertical displacement as a variable, a calculation method for the drop hammer impact force under multiple impacts with different energy levels was proposed. The dynamic response of the hybrid joint under impact loading was studied through the test, with emphasis on the effects of impact velocity and drop hammer mass on the impact force, impact vertical displacement, and correction coefficient. A dimensionless empirical formula for correction coefficient was developed, and a calculation model for drop hammer impact force was established, and its reliability was verified. The results showed that the sleeve thickness had little influence on the impact vertical displacement. The impact velocity and drop hammer mass had significant effects on both the impact force and vertical displacement. The correction coefficient was positively correlated with impact velocity and negatively correlated with drop hammer mass. The proposed calculation model for drop hammer impact force could effectively predict the peak value of drop hammer impact force, and the results showed good agreement with the calculation models based on Hertz elastic theory and Thornton elastic-plastic theory. The findings can provide a theoretical basis for the protection of structures under drop hammer impacts.
