Lightweight Design Of The Open Pre-bending Machine Based On FEA

A company independently designed a hydraulic open pre-bending machine.In order to test whether the stress and deformation of the pre-bending machine meet its material requirements before production,the model of the pre-bending machine was modified and analyzed by using three-dimensional software SolidWorks and finite element analysis software ANSYS-Workbench to meet the production and design requirements.Firstly,the rationality of the pre-bending machine model design was checked in SolidWorks,and the features such as small clearance were merged.The pre-bending machine model was simplified in order to establish seamless connection with the finite element analysis software ANSYS-Workbench.In Workbench,the static analysis module was used to analyze the initial simplified model of the pre-bending machine,and the tetrahedral mesh was used to mesh the finite element model of the pre-bending machine.The analysis results were compared with the design requirements and material requirements.According to the results of static analysis,the location of the maximum stress concentration and the structure which had great influence on the deformation and stress of the pre-bending machine were obtained.The thickness of side plate on the upper cross beam weldment,the thickness of octagonal stiffener plate on the upper cross beam weldment,the thickness of bar plate 1 on upper cross beam weldment and the thickness of side plate on the base weldment were set as parameters,and the parametric modeling was carried out in SolidWorks.The parameterized model of pre-bending machine was imported into Workbench and optimized by response surface optimization module.49 groups of test data were obtained by central composite design.The pre-bending machine was re-modeled according to the final structural parameter data of optimization analysis.Then the optimized model was analyzed by static analysis.According to the results of static analysis and response surface optimization analysis of pre-bending machine,Workbench can only optimize 15 parameters.Through observation and analysis,the diameter of 200 mm tie rod at fuselage maddle part,the thickness of octagonal stiffener plate on the upper cross beam weldment,the thickness of side plate of fuselage,the thickness of bar plate 1 on upper cross beam weldment and the diameter of 140 mm tie rod at fuselage tail were set as parameters.Orthogonal experiment was set up,L16(45)orthogonal table was adopted and combined factor table was established.Prebending machine was modeled according to the combined factor table in SolidWorks.Static analysis was carried out sequentially,and 16 groups of analysis data were obtained.The data of weight,maximum stress and maximum deformation of pre-bending machine after orthogonal test were imported into SPSS18.0 for linear regression analysis,and the linear regression coefficients of the them were obtained.The linear regression equation of them was established,and the size constraint function of the structural parameters of pre-bending machine was designed,thus the lightweight objective function of pre-bending machine was established.The objective function was imported into the optimization toolbox of MATLAB,and the linear regression function linprog was used to calculate it.The optimization value of structural factor variables of the pre-bender was obtained.The model was rounded and modeled.Finally,the static analysis of the lightweight model was carried out,and the final lightweight analysis results were obtained.Through static analysis,response surface optimization design and lightweight design based on orthogonal test,the maximum deformation of the pre-bender is increased by 0.0705 mm,it still meet design requirements,the maximum stress is reduced by 12.85 Mpa,and its weight is reduced by 22040 kg,the lightweight proportion is 8.92%.