When a rice combine harvester operates in the field, its frame vibrates significantly under multi-source excitation forces which can cause complex vibration and structural deformation. The vibration response of combine harvester frame under multi-source excitation was deduced. Based on the multi-source excitation of combine harvester, the chassis frame and the threshing frame were assembled into a complete combine harvester frame, which was used to analyse the constraint modal characteristics and its internal connection. A dynamic model of the combine harvester frame as a 7-degrees of freedom rigid body was developed to obtain modal shape and frequency. The excitation parameters of the dynamic model and its vibration response were developed in MATLAB. Vibration response of rice combine harvester frame was tested to verify the dynamic model. By comparing the independent modal frequency of the chassis frame and threshing frame with that of the complete combine harvester frame, the constant modal frequency of complete combine was shown to be directly related to the independent modal frequency of the chassis frame and the threshing frame. The amplitude of signal simulated by the vibration model of combine harvester frame was consistent with the measured amplitude of the frame, which verified the validity of the dynamic model. The six orders constant modal frequencies of the combine harvester frame were within the operating frequency range that could cause complex vibration coupling and resonance. Vibration response of rice combine harvester frame under multi-source excitation could provide a reference for further improvements in the combine harvester frames.

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多源激励下水稻联合收割机机架的模态振动响应

水稻联合收割机在田间作业时，其机架在多源激振力的作用下会发生剧烈振动，引起复杂的振动和结构变形。推导了联合收割机机架在多源激励下的振动响应。基于联合收割机多源激励,将底盘车架和脱粒车架组装成完整的联合收割机车架,分析其约束模态特性及其内部联系。联合收割机框架作为 7 自由度刚体的动力学模型被开发以获得模态形状和频率。动力学模型的激励参数及其振动响应是在 MATLAB 中开发的。对水稻联合收割机机架的振动响应进行了测试，以验证动力学模型。通过比较底盘架和脱粒架的独立模态频率与完整的联合收割机机架的独立模态频率，表明完整联合收割机的恒定模态频率与底盘架和脱粒架的独立模态频率直接相关。联合收割机机架振动模型模拟的信号幅值与实测机架幅值一致，验证了动力学模型的有效性。联合收割机机架的六阶恒定模态频率在可能导致复杂振动耦合和共振的工作频率范围内。多源激励下水稻联合收割机机架的振动响应可为联合收割机机架的进一步改进提供参考。