基于ANSYS的基质草籽毯成型机挤出口优化与试验

Optimization and experiment of the extrusion outlet of molding machine for substrate grass seed blanket using ANSYS

基质草籽毯成型机以农业废弃物秸秆和牲畜粪便为主要原料,制作绿化用草坪,可以实现连续不间断成型生产。针对现有成型机挤出口质量较大,造成材料消耗多和螺栓连接负担重的现象,以挤出口缩颈处长度、缩颈处宽度、料板厚度和螺栓孔直径为研究对象,运用ANSYS Workbench19.2有限元软件在静态特性分析和参数化建模基础上,基于多目标优化的响应面方法对挤出口模型进行优化,得到尺寸参数最优值:缩颈处长度180 mm、缩颈处宽度60 mm、料板厚度3.5 mm、螺栓孔直径11 mm,此时挤出口部件最大变形和最大等效应力较优化前分别减小了35.95%和13.8%;为了进一步优化挤出口尺寸,利用拓扑优化使零件总质量减轻了36.60%。采用EDEM软件对参数优化和拓扑优化进行验证,得到成型颗粒密度和挤出颗粒质量分别为1383.2kg/m^(3)和2709g。利用优化结果制作样机,与优化前成型装置进行对比试验结果表明:成型颗粒密度和挤出颗粒质量与优化前相比分别提升5.84%和2.88%,进一步发芽和烘干试验表明,优化效果达到预期目标,可为相关设备的研发和生产提供理论参考。

A molding machine of substrate grass seed blanket can take agricultural waste straw and livestock manure as the raw material,in order to fabricate the grass seed blanket after hand-holding and molding,particularly for the green lawn.Among them,aerobic fermentation can be also adopted to add the premixing liquid for complete decomposition.The continuous uninterrupted molding can be realized after drying below 60℃,transportation,and laying.The substrate grass seed blanket can be laid directly or half-buried in the ground for the urban,park,and residential greening.However,the existing molding machine cannot fully meet the large-scale production in the design of the initial size parameters.The weight of the larger support burden can tend to cause the uneven force of substrate at the extrusion outlet during extrusion molding.This study aims to reduce the component force deformation for better molding stability.Structural optimization was implemented with the extrusion outlet at the neck length,neck width,material plate thickness,and bolt hole diameter as the object using ANSYS Workbench 19.2.The maximum deformation was 0.85 mm,and the maximum equivalent force was 191.25 MPa,using parametric modeling.The response surface method(RSM)with multi-objective optimization was used to optimize the design of the squeeze outlet model.The maximum deformation was 0.54 mm,and the maximum equivalent force was 164.85 MPa.The topological optimization of the extrusion port was carried out to remove the unnecessary material dimensions without affecting the static analysis.The total weight of the part was reduced by 36.60%.EDEM software was used to verify the optimized extruded parts as a whole machine.The grass seed blanket molding was analyzed by the discrete element method with a simulation time of 30 s.Furthermore,the data extraction of the test indicators was performed by the post-processing module.The simulation was performed with the molding particle density and extruded particle quality as the indicators,which were 1383.2 kg·m-3 and 2685 g,respectively.The test prototype was made to conduct the germination and drying validation tests.The measured density and mass of the formed substrate grass seed blanket were obtained with an error of 6.7%and 2.7%,respectively,compared with the simulation.The validation test was compared with the test before optimization.The density of the formed particles and the mass of the extruded particles were significantly improved by 5.84%and 2.88%,respectively,before optimization.Consequently,the optimized extrusion outlet can be expected to improve the working efficiency of the forming machine.The formed grass blanket was enhanced with the increase of density between the particles of the substrate grass seed blanket.The quality of the blanket can also fully meet the requirements of the production use in the forming machine of substrate grass seed blanket.