Research On Dynamic Strength And Structure Optimization Of Face-shovel Hydraulic Excavator Attachment

Large-scale hydraulic excavator is widely used in open pit mining and gradually replace the small-sized excavator with the requirement for energy saving, emission reduction and high-efficient exploitation. The domestic research of Large-scale hydraulic is still in the start stage. Therefore, the structural strength of 260 tons of hydraulic excavator was studied in this thesis to lay a foundation for development of hydraulic excavator above 400 tons. Attachment is the key part of the hydraulic excavator,which efficiency and reliability directly affects the productivity of the whole excavator. The research of dynamic structural strength and structural optimization of attachment was implemented, which relies on 260 tons of hydraulic excavator research projects by using discrete element method and multi-body dynamics simulation technology. The main research work of this thesis are organized as the followings:1) According to the original excavator model, geometric details and characteristics of attachment was rebuilt, then box structural boom and stick were discretized by using HYPERMESH.2) According to the actual digging situation of the large hydraulic excavator, the corresponding working condition of mining simulation was built by using EDEM. EDEM dynamic break crowd data was obtained by analyze simulations of stick digging conditions. Then imported the dynamic break crowd data into the rigid-flexible coupling system simulation model to simulating stick digging conditions, which was combining with the CAE models of boom and stick in ADAMS virtual prototype. This simulation study has figured out the condition that the changing structural strength and the distribution of the stress points with different digging gestures of the attachment.3) The maximum static break force was researched by using rigid kinematics model of attachment. This data was input into the rigid-flexible coupling system simulation model to analysis the static structural strength of the attachment. Only dynamic simulation can fully response the structural strength of attachment by comparing the difference between the dynamic simulation and static simulation.4) According to the results of the dynamic structural strength simulation analysis of the attachment, the most dangerous working conditions was extracted for topological optimization of stick. And the conceptual structure model was built according to results of the topological optimization. Dynamic digging simulation of the conceptual structure model was carried in the rigid-flexible coupling system simulation model, which indicated the feasibility of the topological optimization and the conceptual design.All of this research results provide the valuable reference for the design of the working device of the large face-shovel hydraulic excavator.