| With the continuous expansion of the scale of large open-pit mines around the world,electric wheel mining dump trucks are gradually developing to large tonnage.With the same production capacity,large-tonnage mining trucks can reduce the number of vehicles used,increase work efficiency and safety in mining areas,and achieve higher benefits.However,the mining area is mostly temporary road surface,the road surface is uneven,and there are many turns,which puts forward higher requirements for the performance of mining dump trucks.As the main body of the ore bearing,the stiffness and strength of the carriage are directly related to the performance and service life of the vehicle,so the structural design of the carriage is particularly important.In addition,the lightweight design of the carriage has an important impact on the performance of the vehicle such as power and fuel economy.In view of this,the strength and stiffness analysis of the carriage is of great engineering application value to ensure the long-term safe operation of the electric wheel mining dump truck.In this thesis,taking Q345 E low-alloy high-strength steel for electric wheel mining dump truck compartment as the research object,the room temperature and low temperature tensile,impact and fatigue test research is carried out,and on this basis,based on the Chaboche cyclic plastic constitutive model,the compartment is carried out.Based on the finite element analysis under complex working conditions,and based on the topology optimization method,the lightweight design and analysis of the carriage are carried out.The main research work and conclusions are as follows:(1)The tensile,impact and fatigue tests of Q345 E steel were carried out at room temperature and low temperature.The low-cycle fatigue behaviors of Q345 E steel under different cyclic loads and at room and low temperature were compared,with emphasis on the effects of strain amplitude and temperature on the cyclic deformation response.The results show that under the same temperature and different cyclic loads,the cyclic stress-strain response of Q345 E steel exhibits cyclic softening characteristics.When it increases to 0.7%,the number of fracture cycles of the material decreases significantly;under the action of different temperatures and the same cyclic load,when the strain amplitude is 0.7%,the fracture cycles at low temperature increase by 41.74%compared with room temperature;At a value of 0.5%,the cycle times of the material at room temperature are slightly higher than the low temperature results.(2)Based on the Chaboche cyclic plastic constitutive model,the initial parameters of the model were estimated through the low-cycle fatigue test data of Q345 E steel,and the principle of least squares was used based on the MATLAB platform to develop an optimization program to improve the accuracy of the initial parameters and predict the cyclic stress of Q345 E steel-strain relationship.The results show that the Chaboche cyclic plastic constitutive model can predict the cyclic deformation behavior of Q345 E steel.(3)Based on the actual size of the electric wheel mining dump truck,the finite element model of the carriage is established.Based on the Chaboche cyclic plastic constitutive model,the strength of the carriage is analyzed,and the topological optimization design of the carriage is carried out.The results show that the strength of the original carriage meets the design requirements,but some structures have mass redundancy.The optimized carriage can reduce the weight of the carriage by 8.46% under the condition that it meets the strength requirements of the vehicle,which improves the efficiency of the electric wheel mining dump truck.fuel economy. |
PDF Full Text Request