现代农业（柑橘）产业体系建设专项（CARS26）; 中央高校基本科研业务费专项（2662015PY144）; 国家重点研发计划（2017YFD0202001、2017YFD0701400）; 公益性行业（农业）科研专项（201403036）
在双侧果园开沟机机架设计过程中，针对机架强度和刚度问题，利用Creo软件对机架固定段和折叠段进行参数化实体建模，导入到ANSYS Workbench中对机架进行有限元模态分析，得到其前6阶频率和振型，并进行结构性能分析。以结构强度及刚度为优化目标，以低阶模态频率和振动幅度为参考标准，针对固定段机架提出该机架结构的改进方案，采用增添桁架、消除焊接残余应力的方法增加其可靠性。结果表明:改进后的固定段机架前6阶固有频率范围为52.884～135.770 Hz，最大变形量为0.055 724 mm，其低阶模态频率和振动幅度得到有效改善，机架的整体刚性有了很大改进，满足设计要求。模态试验表明，有限元模态分析与模态试验结果的固有频率最大误差百分比为0.857%，振型基本一致。〖JP2〗田间验证试验表明，应用改进后的机架进行开沟作业，作业质量完全符合NY/T 740―2003田间开沟机作业质量标准规定，性能稳定，满足果园开沟机的园艺要求。
The finite element modal analysis of the frame was performed in designing the frame of doublesided orchard ditching machine. Its first 6order frequency and mode shape was obtained and structural performance was analyzed to deal with strength and stiffness issues of frames after importing into ANSYS Workbench whose parametric solid modeling of fixed and folded frames established by Creo. Results showed that the vibration of the fixed section frame was large. It was easy to cause stress concentration and fatigue cracking or even fracture. An improved solution for the frame structure for the fixed section frame was proposed to increase the reliability by adding trusses and eliminating welding residual stress while using structural strength and stiffness as the optimization target with loworder modal frequencies and vibration amplitude as reference standards. The results showed that the first 6order natural frequency of the improved fixed section ranged from 52.884 to 135.77 Hz. The maximum deformation was 0.055 724 mm. The loworder modal frequency and vibration amplitude were effectively improved. The rigidity has been greatly improved to meet requirements of design. The result of modal test showed that the maximum error percentage of the natural frequency of the finite element modal analysis and the modal test results was 0.857%. The vibration mode was basically same. Field validation indicated that the application of the improved frame proved that work quality was in full compliance with the NY/T 740―2003 operation quality standards. The performance was stable,meeting the horticultural requirements of the orchard ditching machine. The combination of finite element modal analysis and structural performance analysis can reduce the customization steps of the initial design,shortening the cycle of mechanical design. It will provide a reference for its practical applications.