The planting area of corn reached 3.71×107 hm2 in China in 2016, and the acreage area of corn reached almost 9×105 hm2 in Xinjiang. The mulching cultivation technology has been applied to the cultivation of maize in recent years, and it has improved the quality and yield of corn. According to the data from National Bureau of Statistics of the People's Republic of China, the yield of the maize can be increased by nearly 30% after using the plastic film mulching cultivation technique. However, the mulching film used after many years has not been recycled left in the field and aged, causing "white pollution" in rural roads and farmland, which has been seriously affected the construction of new rural areas and contaminated the farmland. At present, the recycling equipment of plastic film has been developed, but the large crop root stubble has a great influence on the recovery parts, and the large root stubble and the plastic film has been mixed up together causing plastic film recovery difficulties. As such, the recovery problem of plastic film in large-stubble crops has not been solved well. For this research on residual film collecting machine in Xinjiang, we mainly aimed at the cotton plastic film recovery, and the developed machinery that is capable to separate large stubble crops like corn, sunflower, and tobacco from the plastic residual mulch film. It has been difficult to recycle the corn film because of the bigger corn root stubble, and the roots wrapped together with the plastic film. By using the disc-type plucking mechanism, corn root stubble was firstly pulled out, then, the residual plastic film was recycled, which could effectively solve the problem of collecting corn stubble on recycling the film. However, the double-disc cutters were a little deep in the soil in the working process of plucking the roots, and the mechanism had certain vibration during the cropping process. By the vibration test and the model analysis, the field vibration characteristics of the cropping mechanism were analyzed in this paper. To begin with, the finite element modeling and model analysis were carried out as well as extracting the natural frequencies and modes of the mechanism. Secondly, the dynamic data acquisition and analysis were carried on through the whole field dynamic signal test. The frequency spectrum analysis of FFT (fast Fourier transform) was also carried out in the vibration response of each measuring point. Furthermore, the analysis of spectrum was studied at different measurement points, and the maximum displacement happened at the place where the disc touched the ground. It can be concluded that the main vibration frequency of the measuring point was 19.53 Hz at first six order vibration mode of stubble plucking device, the deformation state of the stubble mechanism was different at different frequencies. The frequencies of stubble collecting mechanism were between 38.176-82.477 Hz at six order vibration mode. The first-order natural frequency 38.176 Hz differed greatly from the model analysis, so it is not in the same frequency range, and the design safety of mechanism would not produce resonance phenomenon. According to Hooke's law, the stress is linearly proportional to the strain in a certain limit range, and the dynamic data in the field test was calculated to obtain the force of the mechanism, and the maximum stress of 4-point at the maximum force was 227.94 MPa, less than the yield strength of ordinary carbon steel 235 MPa, and the structure design met the strength needed. The research result can prevent resonance from the stubble plucking mechanism, and provide a reference to the characteristic analysis of vibration, and the strength design of agricultural machinery equipment.%玉米地膜污染治理中,玉米根茬较大、根系中大量气生根与地膜穿插在一起,致使玉米地膜回收较为困难,该文设计采用圆盘式起茬机构将玉米根茬起出,进行地膜回收,可有效解决玉米大根茬影响地膜回收的问题.但在双圆盘起茬过程中,田间地面不平引起的随机激励和圆盘刀等激励产生的振动频率接近起茬机构固有频率时,将引起共振加速,影响整机结构动态特性与可靠性.采用振动测试与模态分析方法,分析起茬机构田间振动特性,避免机构的共振影响起茬工作.首先,进行模态分析,提取机构固有频率与振型;其次,通过整机田间动态信号测试,进行动态数据采集分析,每个测点的振动响应进行快速傅里叶变换的频谱分析,测点位置的主要振动频率为19.53 Hz,与模态分析的一阶固有频率38.176 Hz相差较大,不在同一频率范围内,机构不会产生共振现象发生.根据胡克定律在一定的比例极限范围内应力与应变成线性比例关系,对田间动态数据进行计算得到机构的受力情况,计算受力最大处的测点4应力为227.94 MPa,小于普通炭钢的屈服强度为235 MPa,满足强度要求.该研究可避免起茬装置的共振发生,可为农机装备的振动特性分析与强度设计提供参考.
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