风电行星架微动疲劳寿命分析及计算

发布时间：2018-07-03 11:55

本文选题：风电行星架 + 微动疲劳　；参考：《大连理工大学》2012年硕士论文

【摘要】：微动疲劳经常发生在伴有相对微小滑动的接触构件中,在工程实际中很常见,我们通常所见的螺栓连接、铆接以及过盈连接等,在相互接触表面都很容易发生微动,从而导致微动疲劳破坏,微动疲劳会大大降低零部件的使用寿命,因此在进行设计时必须要高度注意。风力发电行星架与法兰的连接结构,设计时采用了过盈连接,经有限元分析在过盈配合的接触面两端产生了微动滑移,为了确保行星架的使用寿命,需要对行星架和法兰的过盈连接处进行微动疲劳分析并计算微动疲劳寿命。首先通过均匀试验的方法对原始载荷谱进行筛选,得到能够使行星架产生滑移的载荷,经过有限元计算后,根据接触表面一周的应力分布确定最危险截面。然后根据接触界面端的奇异应力场中心路径的应力分布情况通过应力奇异性参数来判定裂纹的萌生。分析微动疲劳破坏的机理,选择最危险的载荷加载顺序。最后计算微动磨损量并对有限元模型进行修正,建立分步施加磨损量与直接施加最大磨损量两种修正模型,分别得到接触界面的接触应力和切向应力分布,继而求得应力强度因子变化范围,并将其与材料的临界应力强度因子变化范围进行比较来判断裂纹的扩展情况。比较两种不同施加磨损量的计算结果,得到实际载荷作用下的疲劳裂纹扩展情况。结果表面：在实际载荷以最危险的加载顺序加载情况下,分步施加磨损与直接施加最大磨损情况下裂纹分别扩展至279μm和300.4μm后都将停止扩展,直接施加磨损的计算结果裂纹长度较长,用这种方法计算的结果偏于保守。最终计算得到的结果显示,行星架的微动疲劳寿命满足设计要求。
[Abstract]:Fretting fatigue often occurs in contact members with relatively minor slippage. It is very common in engineering practice. We usually see bolt connections, rivets, interference joints, etc., which are easily fretted on contact surfaces. This will lead to fretting fatigue failure, fretting fatigue will greatly reduce the service life of parts, so we must pay close attention to the design. In order to ensure the service life of the planetary frame, the contact structure between the planetary frame and the flange of wind power generation is designed with interference fit, and the finite element analysis results in the fretting slippage at the two ends of the contact surface of the interference fit, so as to ensure the service life of the planetary frame. Fretting fatigue analysis and calculation of fretting fatigue life are needed for the interference joint of planetary frame and flange. First, the original load spectrum is screened by uniform test method, and the load which can make the planetary frame slip is obtained. After finite element calculation, the most dangerous section is determined according to the stress distribution of one week on the contact surface. Then according to the stress distribution of the central path of the singular stress field at the contact interface, the crack initiation is determined by the stress singularity parameter. The mechanism of fretting fatigue failure is analyzed and the most dangerous loading sequence is chosen. Finally, the fretting wear amount is calculated and the finite element model is modified, and two kinds of modified models are established. The contact stress and the tangential stress distribution of the contact interface are obtained, respectively, when the wear amount is applied step by step and the maximum wear quantity is applied directly. Then the range of stress intensity factor is obtained and compared with the variation range of critical stress intensity factor of material to judge the crack propagation. The fatigue crack propagation under actual load is obtained by comparing the calculated results of two different wear amounts. Results Surface: when the actual load is loaded in the most dangerous loading sequence, the crack growth will stop when the crack expands to 279 渭 m and 300.4 渭 m respectively when the wear is applied step by step and the maximum wear is applied directly. The crack length is longer when wear is applied directly, and the results obtained by this method are conservative. The calculated results show that the fretting fatigue life of the planetary frame meets the design requirements.
【学位授予单位】：大连理工大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：TH123.3

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