摘要
蔬菜田间动力机械作为一种新型机器,可以实现不同的收获前机械化作业,车架在田间作业时受到各种载荷作用,会伴随有动载荷影响,有必要对车架进行强度研究与优化设计。研究了其车架基于田间实测应变数据的多目标拓扑优化设计方法。利用Hyper Works软件对该车架进行有限元分析,得到了静应力分析条件下的应力分布,并确定车架的疲劳损伤热点;在数据分析基础上,粘贴应变片,组建动态应变测试系统,采集蔬菜田间动力机械典型作业工况下的载荷时间历程;对实测的应变时间历程数据进行预处理,分析车架在相应工况下的受力情况;利用n Code软件编制载荷谱,进行车架的疲劳分析与寿命预测,以此为基础提出了拓扑优化,构建了综合多种工况、以车架应变能和动态低阶固有频率为响应的多目标拓扑优化数学模型,进行轻量化设计。试验结果表明,车架的交叉焊缝处的疲劳寿命为7. 5×104h,为15个测点中最短疲劳寿命,满足使用寿命要求,车架整体结构强度设计过剩。优化后的车架质量减小443. 55 kg,减轻了53. 47%。
As a new type of machine,field vegetable power machinery can realize different pre-harvest mechanization operations. The frame is subjected to various loads during field operations,which is accompanied by dynamic load. It is necessary to carry out strength research and optimization design of the frame. The multi-objective topology optimization design method based on field measured strain data was studied. HyperWorks software was used to carry out finite element analysis of the frame,the stress distribution under static stress analysis conditions was obtained,and the fatigue damage hotspot of the frame was determined. On the basis of data analysis,the strain gauges were pasted,and the dynamic strain test system was set up to collect the load time history under typical working conditions of field vegetable power machinery. The measured strain time history data was preprocessed,and the force of the frame under the corresponding working conditions was analyzed. The load spectrum was compiled by n Code software,and the fatigue analysis and life prediction of the frame were performed. Based on the analysis and life prediction,the topology optimization was proposed,and a multi-objective topology optimization mathematical model with multiple frame conditions and dynamic low-order natural frequency response was constructed to carry out lightweight design. The test results showed that the fatigue life at the cross weld of the frame was 7. 5 × 104 h,the fatigue life was the shortest among the 15 points,which met the service life requirement,and the overall structural strength of the frame was over-designed. The optimized frame quality was reduced by 443. 55 kg,which was reduced by 53. 47%.
出处
《农业机械学报》
EI
CAS
CSCD
北大核心
2018年第S1期463-469,共7页
Transactions of the Chinese Society for Agricultural Machinery
基金
国家重点研发计划项目(2017YFD0700301)
关键词
蔬菜田间动力机械
车架
应变测试
多目标拓扑优化
field vegetable power machinery
frame
stress-strain test
multi-objective topology optimization
