Life Distribution Transformation Model of Planetary Gear System

Planetary gear systems have been widely used in transportation, construction, metallurgy, petroleum, aviation and other industrial fields. Under the same condition of power transmission, they have a more compact structure than ordinary gear train. However, some critical parts, such as sun gear, planet gear and ring gear often suffer from fatigue and wear under the conditions of high speed and heavy load. For reliability research, in order to predict the fatigue probability life of planetary gear system, detailed kinematic and mechanical analysis for a planetary gear system is firstly completed. Meanwhile, a gear bending fatigue test is carried out at a stress level to obtain the strength information of specific gears. Then, a life distribution transformation model is established according to the order statistics theory. Transformation process is that, the life distribution of test gear is transformed to that of single tooth, and then the life distribution of single tooth can be effectively transformed to that of the planetary gear system. In addition, the effectiveness of the transformation model is finally verified by a processing method with random censoring data.

APPLYING REGRESSION AND STOCHASTIC TIME SERIES ANALYSIS TO THE PREDICTION OF PITTING FATIGUE LIFE FOR GEARS

Based upon the methods for the calculation of load capacity of involute cylindrical gears(ISO / DIS6336), the new method system that can be adaptcd for applying condition is found byapplying regresson analysis and stochastic time series analysis to the prediction of pitting life for thegeart, the function is established between pitting area and revolving period of gear, the theoreticalmodel is advanced for tredicting the pitting fatigue life of gear, the problem it solved for obtainingthe applying model by establishing the residue model, the method it put forward the model aboutpredicting pitting fatigue life of gear with damaged condition under middle / low speed and heavyduty.

Research on mechanical wear life feature fusion prediction method based on temporal pattern attention mechanism

In order to solve the problem of low prediction accuracy when only vibration or oil signal is used to predict the remaining life of gear wear,a gear wear life feature fusion prediction method based on temporal pattern attention mechanism is proposed.Firstly,deep residual shrinkage network(DRSN)is used to extract the features of the original vibration time series signals with low signal-tonoise ratio,and the vibration features associated with gear wear evolution are obtained.Secondly,the extracted vibration features and the oil monitoring data that can intuitively reflect the wear process information are jointly input into the bi-directional long short-term memory neural network based on temporal pattern attention mechanism(TPA-BiLSTM),the complex nonlinear relationship between vibration features,oil features and gear wear process evolution is further explored to improve the prediction accuracy.The gear life cycle dynamic response and wear process signals are obtained based on the gear numerical simulation model,and the feasibility of the proposed method is verified.Finally,the proposed method is applied to the residual life prediction of gear on a test bench,and the comparison between different methods proved the validity of the proposed method.

Relation between Shot Peening Process and Fatigue Life in the Case of Hardening Steels

Nowadays, in the auto industry, the need for improvement of fuel efficiency is getting increased more and more in terms of the global warming, as well as the need of light-weighting of gears, transmission parts. Hence, we’ve studied the relation between the shot peening working conditions and factors for improvement of gear’s fatigue life, and also the relation between the factors for improvement and the fatigue life, applying shot peening to a gear of SNCM220. Also, we examined the relation between the fatigue life and arc height that is utilized as a substitute characteristic for shot peening working conditions, adding its observation here.

飞机牵引滑行工况下前起落架疲劳寿命仿真分析

为使机场运行更加高效经济,提出一种由牵引车将飞机高速牵引滑行至跑道起飞端的新模式。在牵引滑行工况下,前起落架要承受长时间长距离的高速重载荷牵引,同时受牵引车的加速和制动特性的影响,可能导致前起落架疲劳寿命降低。于是,针对飞机前起落架在该工况下的载荷分析以及疲劳寿命验证十分重要。通过Adams软件建立多体动力学模型,模拟真实工况,对不同牵引滑行速度下的牵引车-飞机系统仿真,获取到前起落架的载荷谱信息。结合前起落架有限元模型静力学分析和载荷谱,通过频域寿命分析法,在nCode软件中计算得到前起落架的疲劳寿命。结果表明,高速牵引滑行工况产生的大载荷加剧前起落架疲劳损伤,疲劳损伤从减震支柱凸耳向下阻力臂延展,疲劳寿命缩短3个数量级,需要对前起落架下阻力臂进行结构优化。本文中的研究可以为新牵引滑行模式下前起落架的疲劳寿命结构优化提供参考。

OPTIMUM DESIGN OF HIGH-SPEED RAILWAY LOCOMOTIVE TRACTION GEAR

On the basis of deep investigation of locomotive traction gears manufactured at home and abroad , a variety of measures are putted forward to improve the driving load-bearing capacity and working life of our country's high-speed locomotive traction gears. The measures include the fol- lowing five aspects : optimally selecting the material and heat treatment process , optimally designing the tooth profile . reasonably choosing the manufacture accuracy and technique , optimally choosing the lubricant and the way of lubrication and seal , improving the dynamic feature of the gearing. In the respect of the tooth profile , a hob with optimal cutter angles is designed to make root thickness on the dangerous section as large as possible and the stress concentration as small as possible. Ad- dendum modification coefficient is optimized to minimize the maximum flash temperature in the course of meshing. Finally . finite element analysis method is used to calculate the deformation and the stress of teeth accurately. And on this basis , optimal profile correction and axial modification have been designed with regard to the start , continuious running and high speed travel of the loco- motive .

斜齿轮动态啮合及疲劳寿命分析

为了对高速斜齿轮啮合进行探究,首先通过有限元法构建多自由度的转子-轴承系统动力学方程,并计算齿轮啮合的固有频率,通过Newmark-β法计算位移响应,之后应用KISSsoft建立几何模型并对其齿形在齿廓和齿向两方面进行修形,应用ANSYS Workbench对修形前、后的斜齿轮副进行瞬态分析,并通过在等效应力、疲劳寿命和安全系数方面进行对比分析。结果表明:修形后的斜齿轮等效应力下降,疲劳寿命增加,安全系数提高,证明该修形方式的可行性,为设计高速斜齿轮啮合研究提供了参考。

基于WorkBench和nCode的摆线轮疲劳寿命及可靠性分析

摆线轮作为RV减速器核心零件之一,其疲劳寿命对减速器整机寿命具有重要影响。利用WorkBench有限元分析确定摆线轮接触应力状态及结构薄弱点。在此基础上,以Miner线性损伤累积理论和S-N曲线修正理论建立摆线轮接触疲劳寿命数学模型,然后利用疲劳寿命分析软件nCode Designlife对摆线轮以最大接触应力进行接触疲劳寿命分析,结果与摆线轮以同样载荷工况下的设计寿命计算结果相差7.6%,并确定摆线轮的接触疲劳损伤最大点。最后,依据摆线轮的接触疲劳寿命分析数据确定其可靠度,为摆线轮的结构优化设计及可靠度分析提供参考。

喷丸强化对车辆传动齿轮裂纹扩展影响的研究综述

疲劳断裂是重载车辆传动齿轮的主要失效形式之一,齿轮底部疲劳裂纹的扩展将缩短车辆传动系统的服役寿命,严重时会导致车辆发生安全事故。延缓裂纹扩展的主要方法是在传动齿轮的表面引入一定大小的残余压应力。喷丸技术是一种冷加工表面强化处理工艺,该技术利用高速弹丸冲击材料表面,使零件表层产生塑性应变的同时,在表面和内部引入残余压应力,从而使裂纹闭合的能力得到强化,达到延缓裂纹扩展的强化效果。为了更好地揭示喷丸引入的残余压应力对疲劳裂纹扩展的影响,首先综述了传动齿轮表面疲劳裂纹产生的原因以及疲劳裂纹的扩展行为对重载车辆服役的影响。从强度因子、J积分以及裂纹闭合效应出发,介绍了传动齿轮表面疲劳裂纹扩展的理论以及残余压应力与疲劳裂纹扩展速率之间的关系。其次概述了目前国内外常用的新型有益于将残余拉应力转化为残余压应力的微粒子喷丸、激光喷丸、超声喷丸方法,并与传统机械喷丸技术相比较,阐述了新型喷丸表面强化技术的优缺点。此外,从数值模拟和试验结果两方面,论述了喷丸速度、喷丸角度、弹丸直径、弹丸材质和覆盖率5个工艺参数对在传动齿轮表面引入残余压应力的改善影响。最后对喷丸强化技术在传动齿轮上的多目标参数优化以及多尺度残余压应力与疲劳性能进行了展望,并结合重载车辆的使用需求,强调需要创新设计一种效率高、价格低、适用性广的喷丸技术,以进一步推动喷丸强化在延缓疲劳裂纹扩展方面的持续发展。

基于渐开线齿轮轮廓修形的疲劳寿命分析

提出一种新的齿轮渐开线齿廓修形方法,通过UG软件对修形前后齿轮进行建模,基于疲劳寿命理论,利用Workbench和Fatigue Tool方法建立齿轮CAE模型,完成齿轮接触动力学和疲劳寿命仿真分析。仿真结果表明:修形前后齿轮的最大等效应力和等效应变都出现在齿轮节线和齿根处,且修形齿轮的数据与结果都优于标准齿轮。

汽车变速器齿轮修形对齿轮疲劳寿命的影响研究

新能源卡车变速器齿轮受壳体变形影响易出现疲劳点蚀失效。针对壳体变形问题引入齿轮螺旋线补偿修形,利用Romax Designer对齿轮进行修形优化,改善齿轮的接触斑点,降低齿轮的最大接触应力。修形优化后的齿轮通过变速器疲劳耐久试验,对齿轮寿命提升约一倍。

重载螺旋弧齿锥齿轮疲劳寿命预测

以重载螺旋弧齿锥齿轮传动系统为研究对象,基于齿轮强度计算理论、疲劳累积损伤理论和断裂力学理论等,结合国内螺旋锥齿轮制造工艺及制造技术对重载螺旋锥齿轮传动系统的疲劳特征进行研究。

卷筒纸折页机传动齿轮疲劳寿命预测

以某型号卷筒纸折页机传动系统的传动齿轮为研究对象,采用ANSYS/LS-DYNA软件建立了一对齿轮副啮合的有限元动力学模型,选取小齿轮受拉侧某轮齿的齿根处为危险点,得到其弯曲应力-时间历程;利用基于功率密度的疲劳分析方法对小齿轮进行疲劳寿命预测,计算得到危险点的疲劳寿命为12123.5h。该方法同时考虑应力幅值和频率两个因素对疲劳的影响,与基于Miner损伤理论和名义应力法分析得到的疲劳寿命27974h相比,计算精度更高、更接近实际工作寿命(10800h)。该研究为折页机传动系统的疲劳寿命预测提供了更符合实际的分析方法。

低滑动率摆线正齿轮啮合特性与疲劳寿命研究

为提高齿轮的传动性能,基于啮合线原理提出了一种低滑动率摆线正齿轮。首先通过齿轮啮合原理推导出摆线正齿轮齿廓与过渡曲线方程;然后基于齿廓参数与重合度公式计算得出其最大重合度为3.0134;最后分析了摆线正齿轮啮合过程中的稳定性、接触应力和疲劳寿命。结果表明,高重合度摆线齿轮齿间切向啮合力为1238.2 N,与相同工况下的渐开线标准齿轮相比,减小了5.24%;通过疲劳寿命分析可知,最小疲劳寿命为4.534×10^(6)次,齿面接触应力主要集中在齿轮啮合位置以及齿根部位,因此疲劳破坏易发生于主动轮与从动轮啮合处以及齿根部位。

采煤机截割部齿轮结构瞬态动力学性能与疲劳寿命分析

以MG300/700WD型采煤机为研究对象,分析该采煤机截割部传动系统中的两个关键齿轮,通过有限元分析方法对其进行瞬态动力学分析,确定两个齿轮啮合部位的应力和应变较为集中;同时进一步应用n Code Design Life软件对齿轮疲劳寿命进行分析,确定齿轮啮合部位疲劳寿命最低,约为175 d,与实际情况基本相符,因此初步印证了本次研究的有效性,可为后续的同类型采煤机预防性检修工作提供参考。

采煤机截割部齿轮受力分析与疲劳寿命研究

基于采煤机截割部截割煤岩过程与齿轮动力学特性,介绍一种采煤机截割部齿轮受力与疲劳寿命仿真分析方法。此仿真分析方法需先构建采煤机截割部齿轮仿真模型,由此可分别实现采煤机截割部齿轮受力仿真分析和疲劳寿命仿真分析,获取截割部齿轮受力情况和疲劳寿命情况。为验证此种方法的应用价值,将仿真分析方法应用于某煤矿采煤机生产工程实践。

采煤机截割部齿轮传动系统的齿轮疲劳寿命分析

以MG132/320-WD型采煤机为研究对象,介绍一种基于有限元分析的采煤机截割部齿轮传动系统的齿轮疲劳寿命分析方法。以采煤机规格尺寸、材料特性等参数为基础,构建出齿轮的有限元模型,之后分别对齿轮有限元模型的瞬态动力学特性与疲劳寿命特性进行分析,以此判断齿轮的薄弱点,从而为采煤机截割部齿轮传动系统的优化设计提供支持,确保齿轮传动系统在采煤机运行过程中发挥出最大的作用。

齿轮加工数控刀具的磨损机理与寿命预测研究

数控加工作为现代制造业中重要的加工方式,刀具磨损与寿命管理一直是工程技术领域的重要课题。有效的刀具管理策略可以显著提高加工效率、降低成本、优化加工质量,并对环境保护具有重要意义。因此,对数控加工过程中刀具磨损与寿命管理策略展开深入研究,将为推动数控加工技术的发展和实现可持续制造提供重要支撑。分析了数控加工过程中刀具磨损与寿预测策略。

空调风板的电机齿轮疲劳寿命分析

在空调风板运行过程中,电机齿轮不断啮合,承受着交变载荷的作用,易发生疲劳断裂,影响空调风板运动,进而影响空调的送风功能和整机的可靠性。因此,对电机齿轮的强度和疲劳寿命分析展开研究,具有重要的工程意义。基于有限元法对空调风板的电机齿轮强度和疲劳寿命进行分析,首先,建立了简化后的电机齿轮组有限元模型,得到了齿轮强度。进一步,通过Abaqus与Fe-safe联合仿真,拟合得到齿轮材料Wöhler曲线,进而预测了齿轮的疲劳寿命,在标称力矩下满足要求。最后,讨论了极端情况下齿轮发生疲劳断裂的原因,为运动机构的结构可靠性设计以及电机性能选型提供参考。

基于注意力LSTM的齿轮剩余使用寿命预测

针对旋转机械设备中齿轮剩余使用寿命(RUL,remaining useful life)的预测问题,本文利用长短期记忆(LSTM,long short-term memory)网络在处理时间序列数据方面的独特优势,提出一种将注意力机制和LSTM融合的齿轮RUL预测算法。首先,从齿轮振动信号中分解出最能反映其健康状况的4种时域特征(均方根值、峭度、方差和裕度指标)作为RUL预测网络的输入;其次,以提升RUL预测结果的精度为目标,把LSTM和注意力机制相结合,设计了一种新型的RUL预测网络;最后,使用实验室齿轮全寿命加速疲劳实验台生成的真实数据进行了模型验证,结果表明,本文所提出的注意力LSTM算法在进行齿轮RUL预测时具有较高的预测精度。