涂层-梯度层-基底结构中的热残余应力和应力强度因子研究

IMECH-IR > 力学所知识产出(1956-2008)

	涂层-梯度层-基底结构中的热残余应力和应力强度因子研究
	陈永智
导师	段祝平
	1999
学位授予单位	中国科学院研究生院
学位授予地点	北京
学位类别	硕士
学位专业	固体力学
关键词	热喷涂随机分布孔隙率热残余应力应力强度因子 Fgm Thermal Spraying Random Distribution Porosity Thermal Residual Stress Stress Intensity Factor
英文摘要	热喷涂构件中的热残余应力分布对其使用寿命的影响很大，在涂层和基底之间加入功能梯度材料可以降低构件中的热残余应力。本文用数值方法研究了热喷涂涂层-基底结构中孔隙率的随机分布对结构中热残余应力的影响，以及结构中热残余应力和界面裂纹的应力强度因子与功能梯度层层数之间的关系，并与实验结果相验证。论文由四部分组成。首先，介绍了热喷涂技术的发展历史和目前的主要应用、热喷涂产品中存在的问题以及研究和解决这些问题的方法。其次，研究了涂层中随机分布的孔隙对构件中热残余应力的影响，第三，分析了功能梯度层分层的层数对构件中热残余应力的影响，最后，分析了功能梯度层分层的层数对构件界面裂纹应力强度因子的影响。主要结论为：在期望和方差相同的情况下，涂层中的孔隙率呈高斯分布还是呈均匀分布，对涂层-功能梯度层-基底中的热残余应力的分布影响不大；在基底、涂层和功能梯度层的相对厚度不变的情况下，功能梯度层的层数愈多（即材料性质的过渡愈平缓），涂层-（功能梯度层）-基底结构中的热残余应力愈小；在基底、涂层和功能梯度层的相对厚度不变的情况下，功能梯度层分层的层数愈多，涂层-（功能梯度层）-基底结构的界面裂纹的应力强度因子愈小。; The durability of thermal sprayed coating-substrate components is greatly influenced by the distribution of their thermal residual stress. The thermal residual stress can be effectively reduced by introducing functionally gradient material (FGM) between the coating and the substrate. In this paper, the numerical method is used for researching the influence of random distribution of porosity on the thermal residual stress in the coating-substrate component. The relationship between the thermal residual stress, the stress intensity factors of interface crack and the number of layers of FGM is also obtained, and the conclusions obtained are verified by experimental results. This paper consists of four parts. First, the history of development and the present applications of thermal spraying technology are summarized; Secondly, the research of the influence of random distribution of porosity in the coating to the thermal residual stresses is presented; Thirdly, the influence of the number of layers of FGM to the thermal residual stress is analyzed; And finally, the influence of the number of the layers of the FGM to the stress intensity factors of the interface crack is researched. The main conclusions are: Either the coating porosity obeys the Gaussian distribution or the uniform distribution, the thermal residual stress in the coating-substrate component have basically little difference as long as the expectation and the variation of the random distribution being the same; The thermal residual stress decreases when the number of the layers of the FGM increases (i.e. the gradient of the material properties is more smooth) under the condition that the relative thickness of the coating, the FGM and the substrate keeps the same; The stress intensity factors of the interface crack decrease when the number of the layers of the FGM increases under the condition that the relative thickness of the coating, the FGM and the substrate keeps the same.
索取号	29854
语种	中文
文献类型	学位论文
条目标识符	http://dspace.imech.ac.cn/handle/311007/22872
专题	力学所知识产出(1956-2008)
推荐引用方式 GB/T 7714	陈永智. 涂层-梯度层-基底结构中的热残余应力和应力强度因子研究[D]. 北京. 中国科学院研究生院,1999.

条目包含的文件
文件名称/大小	文献类型	版本类型	开放类型	使用许可
涂层-梯度层-基底结构中的热残余应力和应（8003KB）			开放获取	--	请求全文