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矿用电铲斗杆动态疲劳可靠性仿真分析方法

Simulation and analysis method for dynamic fatigue reliability of shovel stick for mining electric shovel

  • 摘要: 为了减少露天矿用电铲作业过程中随机载荷导致的斗杆断裂现象,提出一种矿用电铲斗杆动态可靠性仿真分析方法。基于矿用电铲实际尺寸参数构建其挖掘和提升部件三维模型,结合其机械系统和电气系统耦合作用,建立工作装置ADAMS-Matlab/Simulink机电仿真模型,获得不同工况下斗杆危险点应力曲线;通过雨流计数法统计应力数据,获取应力幅值、均值和峰值的分布特征,经应力修正得到多级载荷特征参数;采用Schaff非线性理论建立多级载荷作用下矿用电铲斗杆的剩余强度模型,结合全域应力−寿命曲线,得到矿用电铲斗杆的强度退化规律;基于应力−强度干涉理论建立矿用电铲斗杆弯曲疲劳失效极限状态函数,建立矿用电铲斗杆动态可靠性模型,采用主动学习Kriging和Monte Carlo模拟法结合的方法(AK-MCS)计算得到强度退化过程下斗杆的时变疲劳可靠度,提出斗杆的阶段性维护策略。仿真分析发现,不同工况下弯曲疲劳可靠度衰减速度变化趋势一致,均是先慢后快,但受剩余强度衰减速度影响,100%满斗率工况下斗杆弯曲疲劳可靠度衰减时间更早、衰减速度更快,斗杆发生疲劳失效时间提前。结果表明:矿用电铲斗杆动态疲劳可靠性仿真分析方法可以得到复杂工况下矿用电铲斗杆的危险点应力特征和时变疲劳可靠度,为矿用电铲斗杆的可靠性设计与维护提供依据。

     

    Abstract: In order to reduce the stick fracture caused by random load during the operation of the electric shovel in open-pit mines, a simulation and analysis method of the dynamic reliability of the stick of the electric shovel in the mining was proposed. Based on the actual size parameters of the mining shovel, the three-dimensional model of the excavation and lifting parts was constructed, and the ADAMS-Matlab/Simulink electromechanical simulation model of the working device was established in combination with the coupling effect of the mechanical system and the electrical system, and the stress curves of the dangerous points of the stick under different working conditions were obtained. The stress data were counted by the rainflow counting method, and the distribution cha racteristics of stress amplitude, mean and peak value were obtained, and the multi-level load characteristic param eters were obtained by stress correction. The Schaff nonlinear theory was used to establish the residual strength model of the shovel stick under multi-stage load, and the strength degradation law of the shovel stick was obtained by combining the global stress-life curve. Based on the stress-strength interference theory, the bending fatigue failure limit state function of the mining power shovel stick was established, the dynamic reliability model of the mining power shovel stick was established, and the time-varying fatigue reliability of the stick under the strength degradation process was calculated by using the method of active learning Kriging and Monte Carlo simulation method (AK-MCS), and the phased maintenance strategy of the stick was proposed. The simulation analysis shows that the attenuation rate of bending fatigue reliability under different working conditions is consistent, which is slow first and then fast, but due to the influence of the residual strength attenuation rate, the attenuation time of the bending fatigue reliability of the stick is earlier and faster under the condition of 100% full bucket rate, and the fatigue failure time of the stick is advanced. The results show that the dynamic fatigue reliability simulation analysis method of mining electric shovel stick can obtain the stress characteristics of dangerous points and time-varying fatigue reliability of mining electric shovel stick under complex working conditions, which provides a basis for the reliability design and maintenance of mining electric shovel stick.

     

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