圆弧榫连接结构微动疲劳寿命预测模型研究

发布时间：2018-11-09 19:16

【摘要】：微动疲劳损伤广泛存在于各种连接结构的紧密配合件中。据统计,在航空发动机中,榫连接结构的破坏占发动机破坏率的17%以上,所以对航空发动机榫连接结构进行微动疲劳性能研究具有重要意义。本文针对航空发动机压气机燕尾榫连接结构的微动疲劳寿命进行研究,论文的主要内容包括以下三个方面:首先,针对航空发动机压气机燕尾榫结构的微动疲劳问题,对榫头和榫槽分别为圆弧-平面和平面-平面两种接触形式的钛合金模拟试验件,进行了微动疲劳试验。结果表明,微动疲劳寿命随着疲劳载荷的增加而降低;圆弧-平面接触形式榫连接结构的微动疲劳寿命明显高于平面-平面接触形式结构;在试验所选取的榫头接触面圆弧半径分别为30mm、50mm和100mm的三种结构中,圆弧半径为30mm的燕尾榫结构微动疲劳寿命最长。其次,使用损伤力学理论,通过对榫连接结构的接触有限元分析,基于Lemaitre提出的热力学耗散余势能模型,从钛合金材料的基本特性入手,通过引入微动损伤区域局部塑性应变率进行修正,提出了适用于榫连接结构的微动疲劳寿命预测模型,通过对平面-平面和3种平面-圆弧接触形式的燕尾榫结构微动疲劳寿命预测,所得预测结果与试验寿命均在2倍误差分散带之内。最后,利用本文建立的微动疲劳寿命预测模型,预测了不同榫头圆弧半径的圆弧-平面接触形式榫连接结构的微动疲劳寿命,分析结果表明,圆弧-平面接触形式结构中,榫头接触圆弧半径在50~80mm之间时,微动疲劳寿命较长。
[Abstract]:Fretting fatigue damage is widely used in all kinds of close fit parts of joint structures. According to statistics, in aero-engine, the damage of tenon structure accounts for more than 17% of the engine failure rate, so it is of great significance to study the fretting fatigue performance of aero-engine tenon connection structure. In this paper, the fretting fatigue life of the joint structure of the tail tenon of the aero-engine compressor is studied. The main contents of this paper include the following three aspects: firstly, the fretting fatigue problem of the tenon structure of the aero-engine compressor is discussed. Fretting fatigue tests were carried out on titanium alloy simulation specimens with mortise and tenon grooves in arc plane and plane respectively. The results show that the fretting fatigue life decreases with the increase of the fatigue load, and the fretting fatigue life of the circular arc plane contact joint structure is obviously higher than that of the plane contact structure. The fretting fatigue life of dovetail tenon structure with arc radius of 30mm is the longest among the three structures whose arc radius is 30mm / 50mm and 100mm respectively. Secondly, using the damage mechanics theory, through the contact finite element analysis of the tenon joint structure, based on the thermodynamic dissipative potential energy model proposed by Lemaitre, starting with the basic characteristics of the titanium alloy material. By introducing the local plastic strain rate in the fretting damage region, a prediction model of fretting fatigue life for tenon joint structure is proposed. The fretting fatigue life of dovetail tenon structures with plane-plane and three plane-arc contact forms is predicted. The predicted results and test life are within the error dispersion band of 2 times. Finally, using the fretting fatigue life prediction model established in this paper, the fretting fatigue life of the circular arc plane contact joint structure with different mortise arc radius is predicted. The analysis results show that in the circular arc plane contact structure, When the contact arc radius of tenon is between 50~80mm, the fretting fatigue life is longer.
【学位授予单位】：南京航空航天大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：V231.9

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