TC4钛合金喷丸强化工艺的数值研究

发布时间：2018-03-26 16:49

本文选题：TC4钛合金　切入点：喷丸强化　出处：《南京航空航天大学》2017年硕士论文

【摘要】：喷丸强化是一种能有效改善工件表面完整性和提高工件疲劳寿命的表面强化技术,广泛应用于航空、航天、汽车等军民用领域。但由于喷丸过程机理复杂,影响参数众多,目前仍有待进一步研究。本文以TC4钛合金为研究对象,基于有限元方法分析TC4钛合金喷丸强化的机理。通过采用能够反映高速冲击下材料的应变硬化以及应变率硬化效应的Johnson-Cook材料模型定义靶材属性,以及ABAQUS有限元软件等进行建模计算,系统的研究了喷丸工艺参数以及工件表面质量对喷丸强化的影响。主要研究内容为:第一章介绍了钛及钛合金的性能及应用情况,同时对喷丸的强化机制及研究现状作了归纳和总结,并指出了喷丸强化的数值研究对喷丸强化工艺的重要性。第二章对静态隐式和动力学显式有限元算法的基本理论进行了阐述;通过建立喷丸强化的单个丸粒有限元模型,研究了重复撞击次数和丸粒材料对喷丸强化效果的影响。第三章通过ABAQUS的二次开发接口,采用Python语言建模,建立了多丸粒随机喷丸强化有限元模型。基于该模型研究了喷丸时间、喷丸速度、喷丸角度、丸粒直径等参数对残余应力和表面粗糙度的影响。第四章针对靶材表面非理想光滑的情况,采用函数拟合的方法模拟了靶材表面粗糙度情况,建立了含初始表面粗糙度的喷丸强化有限元模型,并利用该模型研究了靶材表面初始粗糙度对喷丸效果的影响。第五章对本文所做的工作进行了总结,并对后续工作进行了展望。
[Abstract]:Shot peening strengthening is a kind of surface strengthening technology which can effectively improve the surface integrity of workpiece and increase the fatigue life of workpiece. It is widely used in military and civilian fields such as aviation, aerospace, automobile and so on. However, because of the complex mechanism of shot peening process, the influence parameters are numerous. In this paper, TC4 titanium alloy is taken as the research object. Based on the finite element method, the mechanism of shot peening strengthening of TC4 titanium alloy is analyzed. The target properties are defined by using the Johnson-Cook material model which can reflect the strain hardening and strain rate hardening effect of the material under high speed impact. The effects of shot peening process parameters and workpiece surface quality on shot peening strengthening are systematically studied. The main contents are as follows: the first chapter introduces the properties and applications of titanium and titanium alloys. At the same time, the strengthening mechanism and research status of shot peening are summarized and summarized. It also points out the importance of the numerical study of shot peening to the shot peening strengthening process. In chapter 2, the basic theory of static implicit finite element method and dynamic explicit finite element method is expounded, and the single shot particle finite element model is established. The effects of repeated impact times and pellet material on shot peening strengthening effect were studied. Chapter 3 was modeled by Python language through the secondary development interface of ABAQUS. Based on the finite element model of stochastic shot peening with multiple pellets, the time, velocity and angle of shot peening were studied. The influence of particle diameter and other parameters on residual stress and surface roughness. In the fourth chapter, the surface roughness of the target is simulated by the method of function fitting, aiming at the non-ideal smooth surface of the target. The finite element model of shot peening with initial surface roughness is established, and the effect of initial roughness of target surface on shot peening is studied by using the model. Chapter 5 summarizes the work done in this paper. The future work is prospected.
【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】：2017
【分类号】：TG668

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