关键词: 冲击锤, 钻凿系统, LS-DYNA3D, 冲击力-侵入深度曲线

Abstract: The process of impact hammer drilling is characterized by high non-linearity and large deformation and damage. The process of its longitudinal impact on concrete was studied by using non-linear finite element program LS-DYNA3D and the deformation and crushing mechanism of concrete under different impact hammer speeds, the impact force, the displacement after penetrating the concrete and impact force-penetrating depth curve of the drilling system were studied. The result shows that the bounces of anvil and bit lead to the many times of percussion of the impact hammer drilling system. In the whole impact and penetration process, the largest impact force peak does not occur at the largest penetration depth. The concrete crushing process under the function of pneumatic impact hammer includes four stages: elasto-plastic deformation, brittle cracking, extrusion crushing and unloading. LS-DYNA3D numerical simulation is used to well represent the physical process of the concrete damage by the penetration of the impact hammer drilling, providing an efficient analysis method for the study of the functioning process of impact hammer on brittle materials and of the optimal design of impact hammer.

Key words: Impact hammer, Drilling system, LS-DYNA3D, Impact force-penetration depth curve