The Finite Element Analyses And Parameter Optimization Of Hydraulic Excavator Working Device

The working device of the hydraulic excavator is the executive body of the function ofthe excavator, the strength of the structure and inherent frequency will affect the performanceof excavator and work efficiency directly. The paper based on the working device as theresearch object, makes the static analysis, modal analysis, harmonic response analysis, fatigueanalysis and parameter optimization for the working devices.First of all, the paper analyses the present situation and developing prospect of theexcavator at home and abroad, then describes the working device of hydraulic excavatorworking condition and the possible failure forms. The three-dimensional solid models of theexcavator working devices, the digging bucket, the arm and the boom are established byPro/E5.0. Then, the finite element models of the hydraulic excavator working devices areestablished by ANSYS Workbench14.5. By defining the material properties, meshing,constraint conditions, adding constraints and applying load. The static strength of the workingdevice is analyzed under the two working conditions. Then, we obtain the stress nephogram,the total deformation nephogram and the nephogram of the deformation in the three axis andso on.And then on this basis, the paper does the modal analysis, harmonic response analysisand fatigue analysis of hydraulic excavator working devices. Then we obtain the naturalfrequency and main vibration type of the digging bucket, the arm and the boom, and thefrequency response and the phase response are obtained under the two working conditions. Aswell as the results such as the minimum life, safety factor, fatigue sensitivity, rainflow matrixand damage matrix and so on are obtained in the constant amplitude loading and variableamplitude loading. Using the results of analysis above, the paper analyses the stability of thehydraulic excavator working devices.For the parameter optimization of the hydraulic excavator working devices, the paperanalyses the relation of the load and the maximum equivalent stress, the total displacement,life and damage for each component in the working devices. Thus, the results of analysisprovide the important reference for the structure optimization and shape optimization of theexcavator working devices.Through the static strength analysis, we obtain the result that the maximum stress occursin the condition of the maximum digging depth, the maximum stress of the digging bucketoccurs in the root of otic placode which connect with digging bucket and arm. The maximumdisplacement occurs in the position of bucket tooth. The hinged position of digging buckethydraulic cylinder and arm, arm and digging bucket, digging bucket and the connecting rodare the dangerous position. The stress is larger in the connecting parts of arm front web andthe lower wing plate, and the root of otic placode of the connecting position of hydrauliccylinder and arm. The maximum stress of boom occurs in the hinged root of boom and arm hydraulic cylinder, the hinged position of boom and arm, the hinged position of arm hydrauliccylinder and boom.Modal analysis finds that the frequency can really influence the working devices in thefirst three modes mostly. The harmonic response analysis finds that the stability of workingdevice except some special points can be guaranteed. Through the fatigue analysis of theworking devices, we obtain the maximum and minimum life cycle and safety factor. Theanalysis shows that the fatigue life and the safety factor are higher under the constant load.Through the parameter optimization of the working devices, we can obtain the optimizedcurve between the designed points and parameters, the total deformation response surface, theminimum and maximum equivalent stress response surface etc. Then we find out theadvantages of parameters.