本文關(guān)鍵詞： 齒形配合面 微動(dòng)疲勞損傷 有限元 裂紋預(yù)測(cè)　出處：《天津大學(xué)》2012年碩士論文　論文類型：學(xué)位論文

【摘要】：本文針對(duì)連桿齒形配合面在服役過程中過早出現(xiàn)裂紋的現(xiàn)象，從微動(dòng)疲勞角度出發(fā)，進(jìn)行裂紋萌生位置和擴(kuò)展方向的觀察統(tǒng)計(jì)，并運(yùn)用有限元軟件建立齒形配合面的接觸模型，展開應(yīng)力場(chǎng)與位移場(chǎng)的數(shù)值模擬和裂紋萌生位置的預(yù)測(cè)，最終提出減緩微動(dòng)疲勞損傷的建議措施，，為工程應(yīng)用提供一定的理論依據(jù)。本文主要包括以下工作和研究成果： 1.對(duì)工程應(yīng)用中因齒形配合面發(fā)生失效的一批連桿進(jìn)行裂紋位置的統(tǒng)計(jì)，得出損傷重點(diǎn)部位為齒形面；從某一典型失效連桿上切割得到齒形面部位，進(jìn)行裂紋萌生位置和擴(kuò)展方向的進(jìn)一步觀察，總結(jié)微動(dòng)疲勞損傷的特點(diǎn)；化學(xué)成分、力學(xué)性能和金相組織等一系列試驗(yàn)檢測(cè)得到連桿材料性質(zhì)，其中力學(xué)性能為后續(xù)有限元分析提供數(shù)據(jù)支持。 2.根據(jù)連桿的動(dòng)力學(xué)分析計(jì)算結(jié)果，應(yīng)用非線性有限元分析軟件ABAQUS對(duì)連桿進(jìn)行多工況接觸分析；在全局模型的基礎(chǔ)上，運(yùn)用子模型技術(shù)建立適于微動(dòng)研究的齒形配合面精細(xì)有限元模型，分析齒面應(yīng)力、位移分布特點(diǎn)。 3.提出累計(jì)Ruiz準(zhǔn)則法，考慮各個(gè)工況載荷大小和作用時(shí)間的不同進(jìn)行加權(quán)，將單一工況的Ruiz準(zhǔn)則統(tǒng)計(jì)值乘以相應(yīng)的加權(quán)系數(shù)，最終得到一個(gè)工作循環(huán)的累計(jì)微動(dòng)疲勞損傷參數(shù)，在對(duì)比短臂端預(yù)測(cè)結(jié)果與實(shí)際損傷位置吻合程度較高后，進(jìn)行了長(zhǎng)臂端齒形面的裂紋位置預(yù)測(cè)，為連桿的改進(jìn)設(shè)計(jì)和損傷評(píng)估提供參考。 4.針對(duì)螺栓預(yù)緊力、配合面摩擦系數(shù)、連桿結(jié)構(gòu)設(shè)計(jì)和表面工程，提出減緩齒形配合面微動(dòng)損傷的改進(jìn)措施，為工程應(yīng)用提供指導(dǎo)。
[Abstract]:In view of the phenomenon that cracks appear prematurely in the service process of the tooth fitting surface of connecting rod, from the angle of fretting fatigue, the observation and statistics of crack initiation position and propagation direction are carried out in this paper. The contact model of tooth fit surface is established by using finite element software, the numerical simulation of stress field and displacement field and the prediction of crack initiation position are carried out. Finally, the suggested measures to reduce fretting fatigue damage are put forward. This paper mainly includes the following work and research results: 1. According to the statistics of the crack position of a batch of connecting rods which have failure due to the failure of the tooth fitting surface in engineering application, it is concluded that the key site of the damage is the tooth shape surface; The tooth profile face position was obtained from the cutting of a typical failure connecting rod. The crack initiation position and propagation direction were observed further, and the characteristics of fretting fatigue damage were summarized. A series of tests such as chemical composition, mechanical properties and metallographic structure are used to test the properties of connecting rod materials, among which the mechanical properties provide data support for the subsequent finite element analysis. 2.According to the dynamic analysis results of the connecting rod, the contact analysis of the connecting rod under multiple working conditions is carried out by using the nonlinear finite element analysis software ABAQUS. On the basis of the global model, the fine finite element model of tooth fit surface is established by using submodel technique, and the distribution characteristics of stress and displacement of tooth surface are analyzed. 3. The accumulative Ruiz criterion method is put forward, considering the different load size and working time of each working condition, the statistical value of Ruiz criterion is multiplied by the corresponding weighting coefficient. Finally, the cumulative fretting fatigue damage parameters of a working cycle are obtained. After comparing the predicted results of short arm end with the actual damage location, the crack location of the tooth surface of the long arm end is predicted. It provides reference for the improved design and damage assessment of connecting rod. 4. Aiming at the pretightening force of bolt, friction coefficient of fit surface, design of connecting rod structure and surface engineering, the improvement measures of reducing fretting damage of tooth fitting face are put forward, which can provide guidance for engineering application.
【學(xué)位授予單位】：天津大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2012
【分類號(hào)】：TH114;TH133.5

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相關(guān)期刊論文 前4條

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本文編號(hào)：1466664