Strength Analysis And Influence Analysis Of Structural Parameters Of Loader Bucket Considering Bulk Strength

As one of the widely used earth-moving machines,loaders usually operate on granular materials such as gravel,sand,soil,etc.The loader bucket is used as a working device in direct contact with the material.The structural strength and optimization design are of great significance to improve the working efficiency of the whole machine and reduce the fuel consumption.Therefore,the accuracy and rationality of the structural strength analysis theory and method will have a direct impact on the subsequent optimization design.At present,scholars mostly use the traditional strength analysis method to calculate the strength of the bucket and other working devices,neglecting the bulk force between material and equipment.On the basis of summarizing the research of strength analysis and structural optimization of buckets at home and abroad,this paper studied the relationship between bulk force and equipment based on the characteristics of materials,put forward a method of strength analysis of buckets considering bulk force.The mechanical response analysis model of the bucket and material was established by a discrete element-finite element coupling method,and the rationality of the method was verified by experiments.Finally,the influence of bucket structure parameters on the working resistance and strength of bucket was analyzed,which provides the basis for the optimization of bucket structure.The main research contents and results were as follows:(1)Discrete element-finite element coupling analysis theory was introduced.Based on analysis theories of the discrete element method and finite element method,the coupling analysis theory of discrete element-finite element was introduced and the coupling form of discrete element-finite element was analyzed.(2)The discrete element simulation of the bucket operation process was established,and the force of the bucket was obtained.Based on the characteristics of the bucket itself,the bucket model was established.The contact parameters between materials and bucket were measured,the shape of rock was reversed by reverse engineering technology and the obtained material profile was filled,then the simulation model of rock was established.Through virtual prototyping technology to carry out kinematics simulation and obtained the movement characteristics of the bucket and setting boundary conditions,then the discrete element simulation of the bucket loading process were completed.The operational resistance of the bucket was obtained.(3)The working resistance obtained by the discrete element method was used as the external load,and strength of bucket was calculated by the finite element method.By visualizing the loading process,the change of material position in the bucket and the working resistance of the bucket at different times in the working process were obtained.The mechanical response of the bucket under the action of bulk force was analyzed by finite element method,and the characteristics of stress and deformation were obtained.(4)The dynamic strain test of loader bucket was completed.After finishing the arrangement of measuring points,the selection of strain gauges and the selection of testing conditions,the dynamic strain test of the loader bucket was carried out.The rationality of the theoretical method was verified by the comparison between the test results and the theoretical calculation results.(5)The influence of bucket structure parameters on operation resistance and strength were analyzed.The parameters that are important in the design of bucket structure were selected for optimization,and the optimized structure was subjected to discrete element simulation to obtain the working resistance of the bucket.The finite element method was used to analyze the strength variation of the bucket under different structures.The influence curves of different structural parameters on the resistance and strength were obtained,after taking these two indexes into consideration,the optimum range of parameters was obtained,the optimum combination of structural parameters was obtained: the side edge angle is 60°,the bottom plate length is 431 mm,the baffle height is 120 mm,and the bucket angle is 42°,which provides a reference for the optimized design of the bucket structure.