It is inevitable to cut reinforced concrete(RC)appeared in cross passage of city metro by cutting tools when constructing in densely populated area.The previous cutters employed to cut RC are insufficient and easily d...It is inevitable to cut reinforced concrete(RC)appeared in cross passage of city metro by cutting tools when constructing in densely populated area.The previous cutters employed to cut RC are insufficient and easily damaged,so a new polycrystalline diamond compact(PDC)cutter is used to solve this question.Based on the theoretical analysis of cutting mechanism,both circular and tapered PDC cutters with cutting edge angle of 90and negative front rack angle of 10are used to cut RC.The peeling and breaking patterns of cutting concrete are proposed,the nodular and grainy chips are the preferred modes in cutting steel bars.The LS-DYNA is employed to investigate the cutting performance in advance.The simulation results show that the average and peak cutting forces increase with the growth of penetration depth,cutting speed,and roundness,and subsequently the recommended penetration depth less than 1.2 mm is obtained to cut RC due to the existence of steel bars.Moreover,the linear cutting platform is adopted to investigate the force ability and damage state of PDC cutters.It is concluded that the cutting force increases abruptly and fluctuates heavily when cutting the coarse aggregates.The patterns occurred in both numerical and experimental results are generally similar.Notably,the steel bar is pulled out and the PDC cutter is damaged at the penetration depth of 0.8 mm,while a good cut occurs at the penetration depth of 0.3 mm.The tapered PDC cutter with a relatively low cutting force is prone to be broken compared with circular PDC cutter.It is suggested that the circular PDC cutter at the penetration depth of 0.3 mm should be used to cut RC in practical engineering.展开更多
为了评价农机入土部件材料的磨损性能,设计了一台磨损性能试验机,通过整体结构和关键部件设计实现了不同材质的旋耕刀/圆盘耙和犁铧部件在特定磨料条件下的磨损性能测试试验。利用ANSYS Workbench有限元分析软件对犁铧磨损试验系统的旋...为了评价农机入土部件材料的磨损性能,设计了一台磨损性能试验机,通过整体结构和关键部件设计实现了不同材质的旋耕刀/圆盘耙和犁铧部件在特定磨料条件下的磨损性能测试试验。利用ANSYS Workbench有限元分析软件对犁铧磨损试验系统的旋转十字架进行静力学分析,根据实际工况添加载荷和约束,分析得到旋转十字架的总变形和应力分布云图,验证了设计的合理性。基于Dyna Test Expert动态试验软件的测控系统实现试验转速、时长等参数的设置,以及试验结果的存储。展开更多
基金supported by the Shanghai Science and Technology Development Funds(Grant No.20QB1401800)Xuzhou Science and Technology Plan Social Development Key Special Project(Grant No.SHFZZDZX20210017)Yunlong Lake Laboratory of Deep Underground Science and Engineering Project(Grant No.104023006).
文摘It is inevitable to cut reinforced concrete(RC)appeared in cross passage of city metro by cutting tools when constructing in densely populated area.The previous cutters employed to cut RC are insufficient and easily damaged,so a new polycrystalline diamond compact(PDC)cutter is used to solve this question.Based on the theoretical analysis of cutting mechanism,both circular and tapered PDC cutters with cutting edge angle of 90and negative front rack angle of 10are used to cut RC.The peeling and breaking patterns of cutting concrete are proposed,the nodular and grainy chips are the preferred modes in cutting steel bars.The LS-DYNA is employed to investigate the cutting performance in advance.The simulation results show that the average and peak cutting forces increase with the growth of penetration depth,cutting speed,and roundness,and subsequently the recommended penetration depth less than 1.2 mm is obtained to cut RC due to the existence of steel bars.Moreover,the linear cutting platform is adopted to investigate the force ability and damage state of PDC cutters.It is concluded that the cutting force increases abruptly and fluctuates heavily when cutting the coarse aggregates.The patterns occurred in both numerical and experimental results are generally similar.Notably,the steel bar is pulled out and the PDC cutter is damaged at the penetration depth of 0.8 mm,while a good cut occurs at the penetration depth of 0.3 mm.The tapered PDC cutter with a relatively low cutting force is prone to be broken compared with circular PDC cutter.It is suggested that the circular PDC cutter at the penetration depth of 0.3 mm should be used to cut RC in practical engineering.
文摘为了评价农机入土部件材料的磨损性能,设计了一台磨损性能试验机,通过整体结构和关键部件设计实现了不同材质的旋耕刀/圆盘耙和犁铧部件在特定磨料条件下的磨损性能测试试验。利用ANSYS Workbench有限元分析软件对犁铧磨损试验系统的旋转十字架进行静力学分析,根据实际工况添加载荷和约束,分析得到旋转十字架的总变形和应力分布云图,验证了设计的合理性。基于Dyna Test Expert动态试验软件的测控系统实现试验转速、时长等参数的设置,以及试验结果的存储。
