Lightweight Research On ZNL-1 Type Understory Weeding Locomotive Frame Based On Sensitivity Analysis

Lightweight design has become an important factor that must be considered in the design of agricultural and forestry machinery,with the development of modern mechanical operation technology.The quality of the frame of agroforestry machinery is relatively large in the whole machine quality.Reducing the quality of the frame can not only reduce fuel consumption,the cost,but also improve the operation efficiency and the operation performance.Therefore,the lightweight design of the frame is of great significance.This paper developed the ZNL-1 type understory weeding locomotive frame as its research object.The main research contents of the paper are as follows:1.The parameterized modeling of the understory weeding locomotive frame was carried out with the 3D modeling software,and it was simplified;Then the model is imported into the finite element analysis software.Add related material properties,and the frame model is meshed by setting a reasonable grid division method and a grid size of a suitable size,thereby a reasonable finite element analysis model of the understory weeding locomotive frame is established.2.According to the actual situation,two typical conditions of horizontal bending and ultimate torsion are selected,Load and constraints are added to the finite element model of the frame with different condition.And the statics analysis of the frame is carried out to verify the strength and stiffness of the frame;And the stress test of the frame is carried out to verify the correctness of the finite element model and the rationality of statics analysis.Then,the constrained modal analysis is carried out by the finite element model which has been verified the reasonable,and the resonance problem is analyzed according to the results.Finally,the static analysis results and modal analysis results of the frame can provide the basis for the sensitivity analysis of the rear frame.3.According to the analysis results of the limit torsional conditions,the mathematical model of the related optimization equation was established and the sensitivity of the weeding locomotive frame was analyzed.The sensitivity of the quality,strength,displacement and first-order modal frequency to the steel pipe thickness of each part of the frame is obtained.Then two evaluation indexes relative sensitivity and average relative sensitivity were introduced.By comparing the two evaluation indexes and combining the sensitivity analysis results,then the suitable optimization design variables were selected for the lightweight design of the rear frame.4.Based on the verified finite element model,The optimization design of the frame is carried out by taking the minimum weight of understory weeding locomotive frame as the goal,component beams which selected after sensitivity analysis as design variables,and the strength,displacement deformation and first order mode of the frame under the limit torsion condition as constraint conditions.The optimal solution is obtained by compared with the optimization scheme which carried out by fuzzy matter-element method based on entropy weight.Through comparative analysis,it is found that the optimized frame achieves a weight reduction of 21.61%based on the performance of the frame.It achieved the lightweight goals.