【作者】 秦宇；

【导师】 李佳；

【作者基本信息】 东北大学 ， 机械设计及理论， 2008， 硕士

【摘要】 在疲劳寿命预测过程中,对随机载荷的分析,大多采用的是考虑随机载荷的幅值和均值对疲劳损伤的影响,致使对随机载荷特征描述不够准确,影响寿命预测的准确性。针对上述这一问题,本文在分析已有疲劳理论和方法的基础上,应用信号分析与处理技术、数理统计方法和分形理论,对随机载荷进行综合分析,提取了能够准确地描述随机载荷的特征参数,包括时域参数、频域参数和形状参数。依据提取的特征参数建立了相似-疲劳寿命预测法。通过比较两个随机载荷的特征参数,判断其相似性。如果材料、加工、环境等条件都相同,并且两个随机载荷相似,则用相似-疲劳寿命法来预测寿命,即运用两个相似随机载荷的等效应力幅值关系、局部修正后的P-S-N曲线及其中一个随机载荷的寿命来计算另一个随机载荷的寿命。如果两个随机载荷不相似,则可以用P-S-N曲线和线性累积损伤理论估算疲劳寿命。为通过软件自动实现以上方法,作者开发了随机载荷的特征参数提取与疲劳寿命预测智能软件系统,该系统具有随机载荷特征参数提取与基于随机载荷特征参数的疲劳寿命预测两大功能。系统利用VB和MATLAB技术,充分发挥这两个软件的优点,使开发的系统具有运算速度快、易于开发和维护以及操作简单的优点。利用VB和Microsoft Access数据库软件的接口技术来建立数据库,使数据库的操作灵活,功能完善。更多还原

【Abstract】 The existent study on the random load during analyses of fatigue life prediction usually considers amplitude and mean of the load, in this way the random load can’t be described exactly, accordingly the fatigue life can’t be predicted accurately.To solve this problem, using signal analyses technology, mathematical statistics method and fractal theory, the author abstracted parameters of the random load from these four aspects, amplitude, time domain, frequency domain, and shape of the random load.In this way, the random load can be described more exactly.Based on these parameters, the author set up the similitude-fatigue life prediction method. If the two random loads are similar, use the relationship of the two equivalent stress amplitudes of the two similar load to predict the unknown life; If the two random loads are dissimilar, use the generally life prediction method, in detail. The P-S-N curve and Miner principle are used in life prediction with generally method.The author also developed the fatigue life prediction system which was based on the parameters of random load for realizing the methd through software. It comprised two primary parts, extracting characteristic parameters and predicting fatigue life. Using technology of VB and MATLAB, the system took the advantages of them, so the system is provided with fast operational speed and friendly interface. Using the interface technology of VB and Microsoft Access software, the system was provided with convenience operation and perfect function.更多还原