Journal of Jilin University(Engineering and Technology Edition) ›› 2022, Vol. 52 ›› Issue (3): 703-715.doi: 10.13229/j.cnki.jdxbgxb20200802

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Design method of tractor durability accelerated structure test

Chang-kai WEN1,2(),Bin XIE1,2(),Zheng-he SONG1,2,Jian-gang HAN3,Qian-wen YANG3   

  1. 1.College of Engineering,China Agricultural University,Beijing 100083,China
    2.Beijing Key Laboratory of Optimized Design for Modern Agricultural Equipment,China Agricultural University,Beijing 100083,China
    3.Luoyang Xiyuan Vehicle and Power Inspection Institute Co. ,Ltd. ,Luoyang 471000,China
  • Received:2020-10-19 Online:2022-03-01 Published:2022-03-08
  • Contact: Bin XIE E-mail:18813003909@163.com;xiebincau@126.com

Abstract:

To solve the problems of unreasonable design and unsystematic analysis of durability test in agricultural machinery testing ground, a design method for tractor fatigue accelerated structure test was proposed. Taking the construction of optimization matrix for accelerated structural test design as the core, the time-domain extrapolation method based on Peak Over Threshold (POT) model, the augmented Lagrangian multiplier method for solving the optimal matrix and the Monte Carlo method for sensitivity analysis were combined. Then, the method was verified by taking standard tractor test site as an example. The results show that the optimal number of repetitions/turns for the four simulated working conditions are 0, 1885, 2392 and 241 respectively. The total duration of the combined test is only 134 h, the acceleration coefficient is 3.2, and the average relative error of damage is only 23.14%, all indexes are better than the traditional fatigue durability test. Compared with the results of Monte Carlo method, the errors of the optimal repetition times of the simulated working conditions are less than 5%, which verifies the accuracy, rationality and effectiveness of the design method of tractor durability accelerated structure test.

Key words: agricultural engineering, tractor durability, accelerated structural test, augmented Lagrangian multiplier method, Monte Carlo method

CLC Number: 

  • S219

Fig.1

Schematic diagram of measuringpoints location on the tractor"

Fig.2

Dynamic stress acquisition system"

Table 1

Main material parameters"

参数数值参数数值
屈服强度σs/MPa310疲劳强度指数b-0.087
抗拉强度σb/MPa450疲劳延性指数c-0.696
杨氏模量E/GPa169疲劳延性系数εf'0.202
泊松比ε0.275

Table 2

Specific parameters of simulation conditions"

工况车速/(km·h-1路径长度/m持续时间/s
12120220
23120144
3512086
4712062

Fig.3

Stress data curve of actual working condition of some measuring points of the tractor"

Table 3

Load extrapolation fitting situation of some measuring points and some working conditions"

工况测点极值类型阈值/MPa形状参数ξ尺度参数σ

拟合

优度

犁耕4极大421.1-0.57461.89510.9682
极小411.1-0.48700.79960.9568
犁耕23极大220.3-0.57845.95810.9763
极小197.1-0.54892.87650.9676
旋耕3极大296.9-0.41900.65600.9675
极小294.2-0.38560.61620.9712
旋耕14极大170.3-0.37351.69110.9549
极小153.9-1.08491.47060.9990
运输6极大20.8-1.12050.14840.9982
极小15.9-0.43790.19040.9650
运输21极大178.7-1.06481.35520.9996
极小135.1-1.58425.14950.9707

Fig.4

Cumulative distribution function diagram of the fitting of the excess of some measuring points"

Fig.5

Time domain extrapolation of measuring point 3 of rotary tillage conditions"

Fig.6

Comparison of rain flow matrix before and after extrapolation of rotary tillage conditions measuring point 3"

Table 4

Comparison of load statistics parametersof measuring point 3"

工况极大值/MPa极小值/MPa均值/MPa方差
犁耕外推前334.8340326.3802331.30452.4804
外推后334.9401326.3712331.30452.4805
旋耕外推前298.4646292.6066296.22340.6725
外推后298.4952292.4966296.22340.6725
运输外推前270.1543264.6678267.37430.5008
外推后270.2805264.4550267.37430.5008

Table 5

Accumulative damage of target load spectrum of actual working conditions"

测点犁耕工况旋耕工况运输工况总损伤
12.29E-012.70E-013.14E-025.30E-01
22.23E-022.02E-025.44E-034.79E-02
31.48E-026.08E-032.46E-032.33E-02
41.19E-019.82E-027.98E-022.97E-01
51.29E-028.22E-035.44E-032.66E-02
64.78E-024.38E-021.23E-012.14E-01
71.09E-015.76E-022.59E-021.92E-01
87.20E-026.38E-029.64E-031.45E-01
94.07E-044.48E-041.88E-041.04E-03
102.98E-032.30E-036.30E-045.91E-03
111.37E-029.72E-032.17E-032.56E-02
123.44E-032.72E-038.38E-047.00E-03
135.73E-027.62E-021.51E-021.49E-01
146.24E-025.16E-021.05E-021.24E-01
154.16E-045.86E-048.98E-051.09E-03
161.27E-019.18E-021.55E-013.74E-01
178.14E-027.48E-021.58E-021.72E-01
187.24E-024.54E-028.62E-031.26E-01
198.58E-027.86E-021.67E-021.81E-01
207.48E-025.04E-028.42E-031.34E-01
212.02E-011.48E-012.12E-015.62E-01
222.87E-042.44E-049.36E-056.25E-04
235.68E-022.74E-024.10E-038.83E-02
241.27E-016.59E-021.80E-022.11E-01

Fig.7

Stress data curve of simulated working conditions of some measuring points of tractor"

Fig.8

Box plot of damage values of all measuring points of 10 simulated conditions"

Table 6

Differences in damage values of 10 simulated conditions of the proving ground"

测点模拟工况1模拟工况2模拟工况3模拟工况4
标准差/%第95百分位数/%标准差/%第95百分位数/%标准差/%第95百分位数/%标准差/%第95百分位数/%
19.8711.4911.3414.4911.2416.5511.9217.37
26.108.865.718.447.6110.579.1112.42
36.649.196.669.026.8110.838.7212.81
48.3112.699.1613.119.7714.5611.5917.47
55.588.986.158.607.0510.998.1512.83
611.2614.109.6513.1510.9615.9612.8816.42
77.359.807.9512.139.2413.5810.3115.31
85.546.506.127.477.1610.989.4012.88
95.176.425.076.035.327.576.677.71
104.986.264.715.875.677.617.419.18
115.146.104.616.126.167.956.789.59
124.876.315.135.695.406.497.369.32
137.0711.638.0110.508.6212.5010.7416.31
147.5810.767.9110.579.1113.179.2314.37
155.546.195.126.086.048.137.278.73
169.0511.688.7013.019.9315.3511.5016.55
177.108.547.2810.177.259.5210.3715.64
188.2710.218.4610.708.5310.169.7614.47
198.3110.837.439.758.2611.3610.0915.03
208.2611.748.1910.618.5011.7711.0415.94
219.0711.889.4113.949.7313.1311.4617.81
224.625.814.504.685.847.947.8310.78
237.5710.567.5110.558.7312.279.5414.35
248.0112.869.2712.929.9415.8311.9515.35

Table 7

Damage of the simulated workingcondition of the proving ground"

测点模拟工况1模拟工况2模拟工况3模拟工况4
14.28E-056.01E-051.88E-041.76E-04
24.16E-065.86E-068.43E-067.91E-06
31.41E-061.95E-064.10E-068.06E-06
42.09E-053.03E-057.00E-052.07E-04
51.65E-062.38E-065.55E-061.02E-05
62.54E-053.58E-057.53E-052.04E-04
71.80E-052.56E-056.03E-055.78E-05
88.15E-061.13E-053.36E-053.05E-05
94.28E-086.07E-088.02E-081.08E-07
101.14E-081.57E-088.38E-084.38E-08
111.62E-082.19E-085.47E-086.07E-08
129.33E-081.30E-074.49E-074.57E-07
138.14E-061.15E-055.34E-055.26E-05
147.21E-061.00E-052.72E-054.79E-05
153.02E-074.25E-079.73E-079.88E-07
162.31E-053.19E-051.27E-041.60E-04
177.01E-069.76E-062.09E-054.57E-05
188.47E-061.19E-054.13E-056.61E-05
197.18E-061.01E-052.12E-055.19E-05
206.59E-069.45E-063.98E-056.69E-05
212.36E-053.33E-051.08E-041.40E-04
222.89E-084.11E-081.04E-071.10E-07
236.67E-069.30E-062.16E-053.90E-05
241.69E-052.34E-057.71E-051.63E-04

Table 8

Solution result of the optimization matrix of the tractor accelerated structure test design"

参数

模拟

工况1

模拟

工况2

模拟

工况3

模拟

工况4

单位时间/s2201408662
重复次数018852392241
试验时间/min043983428249
试验总时间/h134
加速系数3.2

Table 9

Damage comparison between simulatedworking conditions and actualworking conditions"

测点

实际工况

目标损伤

模拟工况

配比损伤

绝对误差相对误差/%
15.30E-016.06E-017.56E-0214.3
24.79E-023.31E-021.48E-0230.8
32.33E-021.54E-027.87E-0333.7
42.97E-012.75E-012.24E-027.5
52.66E-022.02E-026.37E-0323.9
62.14E-012.97E-018.30E-0238.7
71.92E-012.05E-011.45E-027.5
81.45E-011.09E-013.60E-0224.8
131.49E-011.62E-011.31E-028.8
141.24E-019.55E-022.85E-0222.9
163.74E-014.03E-012.86E-027.6
171.72E-017.94E-029.26E-0253.8
181.26E-011.37E-011.12E-028.9
191.81E-018.23E-029.87E-0254.5
201.34E-011.29E-014.80E-0335.7
215.62E-013.54E-012.07E-0236.8
238.83E-027.86E-029.66E-0310.9
242.11E-012.68E-015.70E-0227.0

Table 10

First-order sensitivity analysis result ofoptimization matrix for the design oftractor accelerated structure test"

测点求解次数XPG2求解次数XPG3
模拟工况2损伤情况DPG2模拟工况3损伤情况DPG3模拟工况2损伤情况DPG2模拟工况3损伤情况DPG3
10.23860.3612-0.0273-0.1879
20.17470.1757-0.2334-0.2341
30.17470.1746-0.2330-0.2329
40.16650.1775-0.2236-0.1901
50.17470.1748-0.2330-0.2332
60.26360.1822-0.2099-0.2362
70.18860.1774-0.2406-0.2356
80.17330.1768-0.2313-0.2341
130.17410.1905-0.2359-0.2534
140.17350.1719-0.2324-0.2267
160.23420.1761-0.2776-0.2382
170.16910.1770-0.2167-0.2336
180.17510.1746-0.2345-0.2328
190.19020.1767-0.2444-0.2325
200.17610.1762-0.2336-0.2320
210.30840.31720.0123-0.2211
230.17380.1753-0.2320-0.2329
240.17160.1842-0.2203-0.2109

Fig.9

Frequency histogram of Monte Carlo solution results of trial times/laps"

1 谢斌, 武仲斌, 毛恩荣. 农业拖拉机关键技术发展现状与展望[J]. 农业机械学报, 2018, 49(8):1-17.
Xie Bin, Wu Zhong-bin, Mao En-rong. Development and prospect of key technologies on agricultural tractor[J]. Transactions of the Chinese Society for Agricultural Machinery, 2018, 49(8):1-17.
2 吴思航. 农用万向节传动轴的载荷特点与快速模拟试验方法的探讨[J]. 农业机械学报, 1984(4):55-63.
Wu Si-hang. The research on the load characteristics of agricultural universal joint transmission shaft and rapid analog test program[J]. Transactions of the Chinese Society for Agricultural Machinery, 1984(4):55-63.
3 苏佳, 敖长林, 焦杨. 基于模糊神经网络的拖拉机使用可靠性评价[J].东北农业大学学报, 2008, 39(12): 99-103.
Su Jia, Ao Chang-lin, Jiao Yang. Evaluation of tractor reliability based on fuzzy neural network[J]. Journal of Northeast Agricultural University, 2008, 39(12): 99-103.
4 虞明, 赵济海, 邬惠乐. 随机不平路面上的汽车强化试验研究[J]. 汽车工程, 1993, 15(1):42-53.
Yu Ming, Zhao Ji-hai, Wu Hui-le. Automotive strenuous test on testing track of random surface irregularities[J]. Automotive Engineering, 1993, 15(1):42-53.
5 郭虎, 陈文华, 樊晓燕, 等. 汽车试验场可靠性强化试验强化系数的研究[J]. 机械工程学报, 2004, 40(10): 73-76, 81.
Guo Hu, Chen Wen-hua, Fan Xiao-yan, et al. Research of enhancement coefficient of automobile reliability enhancement test on proving ground[J]. Chinese Journal of Mechanical Engineering, 2004, 40(10):73-76, 81.
6 吴建国, 周鋐, 陈栋华, 等. 目标用户道路谱与试验场道路谱的载荷当量等效模拟研究[J]. 汽车技术, 2007(7):21-24.
Wu Jian-guo, Zhou Hong, Chen Dong-hua, et al. Study on road equivalent simulation based on loading spectrums in customer road and proving ground[J]. Automobile Technology, 2007(7):21-24.
7 于海波, 李幼德, 门玉琢. 一种和用户数据相关的汽车加速疲劳试验新技术[J]. 机械强度, 2008, 30(3):461-466.
Yu Hai-bo, Li You-de, Yu-zhuo Men. New technique for automobile accelerated fatigue test correlated with customer data[J]. Journal of Mechanical Strength, 2008, 30(3):461-466.
8 张新宇. 车辆结构试验场疲劳耐久试验规范及台架试验研究[D]. 北京:清华大学汽车工程学院, 2014.
Zhang Xin-yu. Research on proving ground testing standard and rig testing of durability performance of vehicle structure[D]. Beijing: Department of Automotive Engineering, Tsinghua University, 2014.
9 张禄. 大型营运客车用户关联试验场可靠性理论分析及试验研究[D]. 北京: 中国农业大学工学院, 2015.
Zhang Lu. Reliability theory analysis and test on proving ground correlated with customers usage of big operation vehicle[D]. Beijing: College of Engineering, China Agricultural University, 2015.
10 王世英. 基于车辆损伤贡献分析的试验场耐久性试验方法研究[D]. 长春:吉林大学汽车工程学院, 2019.
Wang Shi-ying. The study of DG durability test method based on vehicle damage contribution analysis[D]. Changchun:College of Automotive Engineering, Jilin University, 2019.
11 Michele M, Giovanni M, Enrico S. Methodology for the realisation of accelerated structural tests on tractors[J]. Biosystems Engineering, 2012, 113(3):266-271.
12 Paraforos D S, Griepentrog H W, Vougioukas S G, et al. Fatigue life assessment of a four-rotor swather based on rainflow cycle counting[J]. Biosystems Engineering, 2014, 127: 1-10.
13 Mattetti M, Molari G, Andrea Vertua. New methodology for accelerating the four-post testing of tractors using wheel hub displacements[J]. Biosystems Engineering, 129: 307-314.
14 Paraforos D S, Griepentrog H W, Vougioukas S G. Methodology for designing accelerated structural durability tests on agricultural machinery[J]. Biosystems Engineering, 149: 24-37.
15 László G, Péter K. A comparative study of destructive effects resulting from road profile acting on off-road towed vehicles[J]. Journal of Terramechanics, 2019, 81: 57-65.
16 . 农林拖拉机和机械-串行控制和通信数据网络 [S].
17 Wen Chang-kai, Xie Bin, Song Zheng-he, et al. Methodology for designing tractor accelerated structure tests for an indoor drum-type test bench[J]. Biosystems Engineering, 2021, 205:1-26.
18 杨子涵, 宋正河, 尹宜勇, 等. 基于POT模型的大功率拖拉机传动轴载荷时域外推方法[J]. 农业工程学报, 2019, 35(15):40-47.
Yang Zi-han, Song Zheng-he, Yin Yi-yong, et al. Time domain extrapolation method for load of drive shaft of high-power tractor based on POT model[J]. Transactions of the CSAE, 2019, 35(15):40-47.
19 林志强, 苏万华. 基于LaGrange-SUMT方法的全电控柴油引燃天然气发动机MAP优化标定技术[J]. 内燃机学报, 2004, 22(5):385-390.
Lin Zhi-qiang, Su Wan-hua. A mapping technique based on the LaGrange-SUMT method for a pilot ignited CNG engine[J]. Transactions of CSICE, 2004,22(5):385-390.
20 林巨广, 杨兰和, 刘明周, 等. 基于工序能力指数的零件选配优化模型[J]. 农业机械学报, 2007, 38(4): 130-134, 117.
Lin Ju-guang, Yang Lan-he, Liu Ming-zhou, et al. Study on optimization model of matching parts assembly based on the process capability index[J]. Transactions of the Chinese Society for Agricultural Machinery, 2007, 38(4): 130-134, 117.
21 宗钟凌, 郭小明. 基于接触协同作用结构非线性屈曲分析[J]. 工程力学, 2011, 28(6):40-44.
Zong Zhong-ling, Guo Xiao-ming. Nonlinear buckling analysis of structure based on contact synergy[J]. Engineering Mechanics, 2011, 28(6):40-44.
22 Jiang Yan, Li Xu-yong, Huang Chong-chao, et al. An augmented Lagrangian multiplier method based on a CHKS smoothing function for solving nonlinear bilevel programming problems[J]. Knowledge-Based Systems, 2014, 55:9-14.
23 高翔, 王林军, 杜义贤. 采用增广乘子法和模拟退火法的结构可靠性分析[J]. 西安交通大学学报, 2019, 53(7):144-152.
Gao Xiang, Wang Lin-jun, Du Yi-xian. Structure reliability analysis by combining augmented multiplier method and simulated annealing algorithm[J]. Journal of Xi'an Jiaotong University, 2019, 53(7):144-152.
24 张将伟, 卢文喜, 曲延光, 等. 基于Monte Carlo方法的地表水地下水耦合模拟模型不确定分析[J]. 水利学报, 2018, 49(10):1254-1264.
Zhang Jiang-wei, Lu Wen-xi, Qu Yan-gaung, et al. Uncertainty analysis of surface water and groundwater coupling simulation model based on Monte Carlo method[J]. Journal of Hydraulic Engineering, 2018, 49(10):1254-1264.
25 陈浩然, 崔利杰, 任博, 等. 不确定条件下航空不安全事件灵敏度分析的Monte-Carlo方法[J]. 北京航空航天大学学报, 2020, 46(2):414-421.
Chen Hao-ran, Cui Li-jie, Ren Bo, et al. Sensitivity analysis for aviation insecure event using Monte-Carlo method under uncertain condition[J]. Journal of Beijing University of Aeronautics and Astronautics, 2020, 46(2):414-421.
26 李园园, 陈国平, 孙东阳, 等. 柔性关节机械臂不确定性及灵敏度分析[J]. 振动·测试与诊断, 2017, 37(6):1141-1148, 1278.
Li Yuan-yuan, Chen Guo-ping, Sun Dong-yang, et al. Uncertainty and sensitivity of flexible-joint manipulator[J]. Journal of Vibration, Measurement & Diagnosis, 2017, 37(6): 1141-1148, 1278.
27 谢斌, 温昌凯, 杨子涵, 等. 基于实测载荷的蔬菜田间动力机械车架结构优化[J]. 农业机械学报, 2018, 49():463-469.
Xie Bin, Wen Chang-kai, Yang Zi-han, et al. Structure optimization of frame for field vegetable power machinery based on measured load data[J]. Transactions of the Chinese Society for Agricultural Machinery, 2018, 49(Sup.1):463-469.
28 温昌凯, 谢斌, 杨子涵, 等. 基于功率密度的大功率拖拉机变速箱壳体疲劳分析[J]. 农业机械学报, 2019, 50(6):389-396, 404.
Wen Chang-kai, Xie Bin, Yang Zi-han, et al. Fatigue analysis of gearbox shell of high horsepower tractor based on power density[J]. Transactions of the Chinese Society for Agricultural Machinery, 2019, 50(6):389-396, 404.
29 Wen Chang-kai, Xie Bin, Li Zhen, et al. Power density based fatigue load spectrum editing for accelerated durability testing for tractor front axles[J]. Biosystems Engineering, 2020, 200: 73-88.
30 秦嘉浩, 李臻, 光岡宗司, 等. 基于模型实验的拖拉机配置对稳定性的影响差异[J]. 吉林大学学报:工学版, 2019, 49(4):1236-1245.
Qin Jia-hao, Li Zhen, Mitsuoka M, et al. Significance variation of factorial effects on tractor stability employing scale-model-based experimental approach[J]. Journal of Jilin University(Engineering and Technology Edition), 2019, 49(4):1236-1245.
31 彭贺, 马文星, 王忠山, 等. 丘陵山地拖拉机车身调平控制仿真分析与试验[J]. 吉林大学学报:工学版,2019,49(1):157-165.
Peng He, Ma Wen-xing, Wang Zhong-shan, et al. Control system of self-leveling in hilly tractor body through simulation and experiment [J]. Journal of Jilin University (Engineering and Technology Edition),2019,49(1):157-165.
32 . 球墨铸铁-分类 [S].
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