小直径开缝衬套冷挤压强化孔疲劳寿命研究

发布时间：2018-03-18 02:15

本文选题：开缝衬套　切入点：冷挤压　出处：《南京航空航天大学》2016年硕士论文　论文类型：学位论文

【摘要】：随着C919大客机成功总装下线,我国民用航空事业的发展又迈开了新的篇章。然而,民用航空事业的迅速发展,必然加大对飞机疲劳寿命使用要求的提高。开缝衬套冷挤压强化技术能够显著提高飞机上紧固孔的疲劳寿命,因此该技术正被广泛地应用于航空工业领域。本文针对直径在10mm以下范围的开缝衬套进行了冷挤压数值模拟仿真,研究该技术对带孔试件疲劳增寿效果的影响,主要工作及取得的成果如下:1.建立了带孔试件冷挤压强化有限元模拟仿真模型,对不同材料的带孔试件进行有限元模拟仿真。研究不带开缝衬套与带开缝衬套时,冷挤压强化工艺对不同材料带孔试件孔周围切向应力分布的影响;同时,改变挤压量,研究挤压量的变化对孔周围切向应力分布的影响。2.在获得有限元仿真结果的基础上,对7050铝合金带孔试件进行了全寿命疲劳仿真和应变寿命疲劳仿真,获得了衬套有无、挤压量变化、疲劳载荷变化等因素对其疲劳寿命的影响情况;建立了TC4钛合金带孔试件冷挤压强化全寿命疲劳仿真模型,通过改变衬套的有无、挤压量的大小以及疲劳载荷的大小来研究这些因素对试件疲劳寿命的影响情况。3.建立了7050铝合金和TC4钛合金带孔试件在不同挤压量和不同载荷条件下经开缝衬套冷挤压强化以后疲劳裂纹扩展仿真模型,获得带孔试件的疲劳裂纹扩展仿真寿命。通过获得的疲劳寿命仿真值,将疲劳裂纹扩展仿真寿命结果与全寿命疲劳仿真和应变寿命疲劳仿真结果作比较。4.就全寿命疲劳仿真模型、应变寿命疲劳仿真模型以及疲劳裂纹扩展仿真模型角度着手,从疲劳寿命增强倍数方面分析,研究开缝衬套冷挤压强化技术对不同材料的带孔试件疲劳增寿效果的影响。5.在VS2010开发平台上,借助MFC类库,使用C++语言,结合ABAQUS脚本文件、MATLAB引擎、SQL语言,综合开发了一套完整的开缝衬套冷挤压强化疲劳寿命预测系统,该系统集ABAQUS二次开发平台、疲劳寿命预测平台和数据库管理平台于一体,将本文研究的方法进行了优化,内容进行了汇总。
[Abstract]:With the successful final assembly of the C919 passenger plane, the development of civil aviation in China has opened a new chapter. However, the rapid development of civil aviation, It is necessary to increase the requirements for aircraft fatigue life. The cold extrusion strengthening technology of slit bushing can significantly improve the fatigue life of fastening holes in aircraft. Therefore, this technology is being widely used in aviation industry. In this paper, the cold extrusion numerical simulation of slit bushing with diameter less than 10mm is carried out to study the effect of this technology on fatigue life increase of specimen with holes. The main work and results obtained are as follows: 1. The finite element simulation model of cold extrusion strengthening specimen with holes is established, and the finite element simulation of different materials with holes is carried out. When there is no slit bushing and slotted bushing, The influence of cold extrusion strengthening process on the tangential stress distribution around the hole of different materials with holes, and the influence of the change of extrusion quantity on the distribution of tangential stress around the hole by changing the extrusion amount. 2. On the basis of the finite element simulation results, The full life fatigue simulation and strain life fatigue simulation of 7050 aluminum alloy specimen with holes were carried out, and the influence of the factors such as the existence of bushing, the change of extrusion amount and the change of fatigue load on the fatigue life of 7050 aluminum alloy specimen were obtained. In this paper, the fatigue simulation model of cold extrusion strengthened whole life of TC4 titanium alloy specimens with holes is established. By changing the existence or absence of bushing, The influence of these factors on fatigue life of specimens was studied by the size of extrusion amount and fatigue load. 3. The slotted bushing of 7050 aluminum alloy and TC4 titanium alloy with holes was established under different extrusion and load conditions. Simulation model of fatigue crack growth after cold extrusion, The fatigue crack propagation simulation life of the specimen with holes is obtained. The simulation results of fatigue crack growth are compared with those of full life fatigue simulation and strain life fatigue simulation. 4. From the point of view of full life fatigue simulation model, strain life fatigue simulation model and fatigue crack growth simulation model, Based on the analysis of fatigue life enhancement multiple, the effect of cold extrusion strengthening technology of slit bushing on fatigue life increasing effect of different materials with holes is studied. 5. On the VS2010 development platform, with the help of MFC class library, C language is used. Combined with ABAQUS script file and ABAQUS engine language, a set of integrated cold extrusion strengthened fatigue life prediction system for slit bushing is developed. The system integrates ABAQUS secondary development platform, fatigue life prediction platform and database management platform. The method studied in this paper is optimized and the content is summarized.
【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】：2016
【分类号】：V215.5

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