Sensitive Parameters Optimization Design And Experimental Verification Of LNC8Rice Transplanter Frame

Rice transplanter is a kind of agricultural machinery used for planting rice, its workenvironment is paddy field and gravel, mud road. It is quite different from road vehicle, for thatreason the frame of the rice transplanter should be designed in a different way, how to reduce theweight of the frame and ensure the security is a big problem in frame designing. The object ofstudy, LNC8rice transplanter frame, has some problem of low working efficiency and lack ofstrength happens unpredictably because of the traditional design method. The optimum designmethod of the thesis remedies the defects perfectly. The main content of the thesis is as follows:1) Raise the background, meaning and source of the thesis, expound the research status ofthe FEA, the sensitivity analysis and the orthogonal experiment. Raise an optimized designscheme based on the problem existed in the frame design, determine the main contents of thisthesis.2) Expound the basic idea and step of the finite element method, introduce the mainfunction, components, material property and connection mode of the LNC8rice transplanterframe. Create an FEM model by a parameterization method, according to the results of the staticanalysis and modal analysis, we know the maximum stress of the frame is46.8MPa, the first sixnatural frequencies is[28.9，35.8，40.3，40.5，62.7，67.5]Hz.3) The sensitivity analyses are made for8parameters of the frame. Choose the thickness ofsupport beam, rack beam, the right board and left board of the operator’s seat which are moresensitive to the maximum stress and inherent frequency of the frame as the design variable of theorthogonal experiment.[3mm,3mm,2mm,2mm] is the optimized process parameter scheme.According to the results of the static analysis and modal analysis of the LNC8rice transplanterframe after optimal design, the maximum stress is59.6MPa, the first six natural frequencies is[25.7，32.5，37.4，54.2，67.7，103.3]Hz, the maximum stress of torsional condition is62.3MPa,the quality of the frame was reduced by9.6%.4) Design a modal analysis test of the LNC8rice transplanter frame using the test facility ofECON modal analysis test equipment. According to the test, the first six natural frequencies is[25.7，32.5，37.4，54.2，67.7，103.3]Hz, avoiding the vibrational frequency45Hz of the engine.After analysis, the maximum error of the inherent frequency between the finite element modal 5) Analyze road condition of the LNC8rice transplanter, choose corresponding powerspectral density as the inputting loads of the random vibration analysis refer to GJB150.1-86.Analyze the vibration displacement, vibration velocity and vibration acceleration in the threedirections, the maximum stress of the frame is62.2MPa, which is conform to the strengthrequirement of the frame. It provided a primary data for the the fatigue life analysis of the frame.6) Summarize the research contents of the thesis, put forward a primary thoughts forfollowing research.