Abstract：In operating load of tractor power take-off (PTO), no damage or small damage load occupies a large proportion to cause long test time and poor economy in durability tests. Eliminating these loads can obtain the acceleration load spectrum. Here, taking a 40 HP tractor as the study object, Daubechies wavelet was used to decompose the measured load signal of the tractor PTO, reconstruct high frequency wavelet coefficients and get high frequency wavelet components. On the premise of the total pseudo damage remaining basically the same, the appropriate threshold was selected and combined with the envelope damage identification method, load segments with larger damage were extracted from the original load signal and spliced into the acceleration load spectrum. Acceleration load spectra with compression ratios of 42.0%, 49.8%, 61.7%, 62.4% and 81.9% were obtained, respectively. Based on theories of frequency domain, amplitude domain, statistical parameters and fatigue damage, the correctness of the obtained acceleration load spectrum and its similarity to the original load spectrum were verified. The results showed that frequency domain and amplitude domain distribution curves of the acceleration load spectrum and the original load spectrum are similar on the premise of the pseudo damage being basically the same; errors of its maximum value, root mean square value, kurtosis coefficient and other parameters all are less than 5%; the damage effect of components is basically the same; the proposed load acceleration editing method is suitable for making acceleration load spectrum of tractor components, and can provide a reference for making acceleration load spectrum in agricultural machinery field.
李淑艳，杨世钊，翟友邦，赵致远，宋正河. 基于小波变换的拖拉机PTO载荷加速编辑方法[J]. 振动与冲击, 2021, 40(13): 167-173.
LI Shuyan, YANG Shizhao, ZHAI Youbang, ZHAO Zhiyuan, SONG Zhenghe. Editing method of tractor PTO load acceleration based on wavelet transform. JOURNAL OF VIBRATION AND SHOCK, 2021, 40(13): 167-173.
［1］李文礼，石晓辉，邹喜红，等. 车辆传动系道路负载模拟系统［J］. 振动与冲击，2016，35(5)：163-167.
LI Wenli，SHI Xiaohui，ZOU Xihong，et al，A dynamic road load simulation system for vehicle drivetrains［J］.Journal of Vibration and Shock, 2016，35(5)：163-167.
［2］于佳伟，郑松林，赵子顺，等. 一种新的加速耐久性试验谱编制方法［J］. 机械强度, 2016，38(2)：356-363.
YU Jiawei，ZHENG Songlin，ZHAO Zishun，et al. A new spectrum development methodology for accelerated durability test［J］. Journal of Mechanical Strength, 2016, 38(2): 356-363.
［3］朱涛，宋健，李亮. 复现试验场工况的转向拉杆室内加速疲劳试验［J］. 公路交通科技, 2010(2)：129-132.
ZHU Tao，SONG Jian，LI Liang. Accelerated fatigue testing of steering link in lab reproducing proving ground scenario［J］. Journal of Highway and Transportation Research and Development, 2010(2)：129-132.
［4］陈永成. 拖拉机动力输出装置的正确使用［J］. 农村机械化, 2000(1):30.
CHEN Yongcheng. Correct use of tractor power take-off［J］. Rural Mechanization, 2000(1):30.
［5］BANVILLET A，VITTORI J F, PALIN-LUC T. How to reduce the duration of multiaxial fatigue tests under proportional service loadings［J］. International Journal of Fatigue, 2006，28：554-563.
［6］于佳伟，郑松林，赵礼辉，等. 整车室内道路模拟试验用载荷谱的编制方法研究［J］. 机械工程学报, 2015(14)：93-99.
YU Jiawei，ZHENG Songlin，ZHAO Lihui，et al. Research on spectrum development methodology for vehicle indoor road simulation test［J］. Journal of Mechanical Engineering, 2015(14)：93-99.
［7］沈永峰，郑松林，王治瑞，等. 轿车摆臂加速模拟试验研究［J］. 现代制造工程, 2013(8)：47-52.
SHEN Yongfeng，ZHENG Songlin，WANG Zhirui，et al. Research on accelerated simulation test of automotive swing arm［J］. Modern Manufacturing Engineering, 2013(8)：47-52.
［8］郑松林，周亚捷，冯金芝，等. 一种新的考虑伪损伤保留的道路载荷模拟试验加速方法［J］.机械强度, 2017(2)：410-416.
ZHENG Songlin，ZHOU YaJie，FENG Jinzhi，et al. A new spectrum development methodology based on pseudo damage reserving for road load simulation test［J］. Journal of Mechanical Strength， 2017（2）：410-416.
［9］邹喜红，杨真亮，袁冬梅，等. 考虑低载强化效应的变速器加速试验谱的编制［J］. 机械传动， 2016（4）：4-9.
ZOU Xihong，YANG Zhenliang，YUAN Dongmei，et al. Compilation of the accelerated test sprctrum of transmission based on low loading strengthening effect［J］. Journal of Mechanical Transmission, 2016(4)：4-9.
［10］杨真亮. 基于实际载荷谱的汽车变速器台架强化试验方法研究［D］. 重庆：重庆理工大学. 2016.
［11］PANU P，PAK S L，RICHARD S C. Extracting fatigue damage parts from the stress-time history of horizontal axis wind turbine blades［J］. Renewable Energy，2013，58：115-126.
［12］PANU P，PAK S L, RICHARD S C. Wavelet transform-based stress-time history editing of horizontal axis wind turbine blades［J］. Renewable Energy，2014，63：558-575.
［13］郑国峰. 典型汽车部件载荷谱及加速耐久性编辑与实验方法研究［D］. 广东：华南理工大学，2017.
［14］郑国峰，上官文斌，韩鹏飞，等. 基于小波变换的汽车零部件加速耐久性多轴载荷谱编辑方法研究［J］. 机械工程学报，2018，54(10)：156-166.
ZHENG Guofeng，SHANGGUAN Wenbin，HAN Pengfei，et al. Study of load spectrum edition method based on the wavelet transform to the accelerated durability test of the vehicle component［J］.Journal of Mechanical Engineering, 2018，54(10)：156-166.
［15］LEE Y L, PAN J, HATHAWAY R B. 疲劳试验测试分析理论与实践［M］. 张然治,译. 北京：国防工业出版社, 2011.
［16］农业部农业机械化管理司. 旋耕机作业质量：NY/T 499—2013［S］. 北京：中华人民共和国农业部, 2013.
［17］王山明.商用车变速器载荷谱编制关键技术研究［D］. 太原: 太原理工大学, 2017.
［18］刘鸿文. 材料力学［M］. 北京: 高等教育出版社, 2012.
［19］翟新婷. 基于外推改进的工程机械载荷谱编制方法研究［D］.吉林：吉林大学，2018.
［20］于知杉. 履带车辆综合传动装置驱动载荷谱应用研究［D］. 哈尔滨：哈尔滨工业大学，2017.
［21］李舜酩. 机械疲劳与可靠性设计［M］. 北京：科学出版社，2006：78-81.
［22］金锋. 加速疲劳试验的疲劳编辑技术探讨［J］. 上海汽车, 1999(2)：17-21.
JIN Feng. Discussion on fatigue editing technology for accelerated fatigue test［J］. Shanghai Auto, 1999(2)：17-21.
［23］DAUBECHIES T. 小波十讲［M］. 李建平，杨万年,译. 北京：国防工业出版社，2011
［24］孙延奎. 小波分析及其应用［M］. 北京：机械工业出版社，2005.
［25］何立志. 希尔伯特-黄变换及其在结构损伤识别中的应用［D］.北京：北京工业大学,2006.
［26］于佳伟，郑松林，冯金芝，等. 某轿车前副车架服役载荷模拟试验加速方法研究［J］. 机械工程学报， 2016，52（22）：112-120.
YU Jiawei，ZHENG Songlin，FENG Jinzhi，et al. Research on accelerated testing method for the service-simulation fatigue test of automotive front sub-frame［J］. Journal of Mechanical Engineering,2016，52（22）：112-120.
