摘要
以某联合收获机主机车身框架为研究对象,采用有限元柔性体技术创建车身框架的有限元柔性体模型,并在其基础上进行模态分析与计算。结果表明,车身框架的第一阶模态频率为7.29 Hz,与收获机正常工作时割刀的激励频率(7Hz)接近,易发生共振,且对人体舒适性影响最大。为了调整收获机车身框架的固有频率,以避开外部激振频率范围,采用HyperMesh软件对收获机车身框架柔性体模型进行尺寸优化和拓扑优化,结果表明,尺寸优化后,收获机车身框架的第一阶模态频率由优化前的7.29 Hz提升至8.63 Hz,车身框架质量下降了0.006t;拓扑优化后,收获机车身框架的第一阶模态频率由优化前的7.29Hz提升至8.49Hz,车身框架质量下降了0.107t。拓扑优化与尺寸优化均可使收获机车身框架固有频率避开外部激振频率范围,但综合考虑优化设计的目标与生产制造成本,采用尺寸优化技术对收获机车身框架进行结构优化更为适合。
The body frame of a combine harvester was used to build the body frame geometry model.As the complexity of the body frame structure of the harvester,the road motions,cutter excitation,threshing roller excitation and other vibration generated by the body frame will be passed to the driver.In order to simulate the process of vibration excitation to the human body frame in a more appropriate way,it is necessary to soften the harvester body frame that conducted the vibration excitation.Based on the geometry model,the finite element soft body frame analysis is used to establish the finite element soft body frame model of the vehicle body frame.The modal analysis and calculation are carried out on the basis of the new model.In the structural vibration,the influence on the dynamic behavior of the structure of lower order mode is more than that of the higher order mode.The low order mode determines the dynamic characteristics of the structure.The body frame structure was optimized with the first-order mode.The results showed that the first-order modal frequency of the body frame of 7.29 Hz is close to the excitation frequency(7 Hz)of the cutter when the harvester works normally,which is prone to resonance and has the greatest impact on human comfort.In order to adjust the natural frequency of the body frame of the harvester to avoid the external excitation frequency range,the size and topology of the model of the vehicle body frame were optimized with HyperMesh software.The results showed that the first-order modal frequency of the harvesting machine body frame upgraded to 8.63 Hz from the 7.29 Hz.The body frame mass decreased by 0.006 t after the size optimization.After topology optimization,it was the same that the first-order modal frequency of the harvesting machine body frame was improved to 8.49 Hz from 7.29 Hz.The body frame quality was reduced by 0.107 t.The natural frequency of the harvester body frame can avoid the external excitation frequency range by optimizing topology and size.Considering the goal of desig
作者
刘爽
徐红梅
周杰
钟文杰
刘海悦
LIU Shuang ;XU Hongmei;ZHOU Jie ;ZHONG Wenjie;LIU Haiyue(College of Engineering,Huazhong Agricultural University/Key Laboratory of Agricultural Equipment in Mid-lower Yangtze River, Ministry of Agriculture,Wuhan 430070,China)
出处
《华中农业大学学报》
CAS
CSCD
北大核心
2018年第3期108-116,共9页
Journal of Huazhong Agricultural University
基金
国家自然科学青年基金项目(51405178)
关键词
收获机车身框架
共振
模态分析
尺寸优化
拓扑优化
harvester body frame
resonance
modal analysis
size optimization
topology optimization
