热循环下热障涂层应力的数值模拟

摘要本文采用有限元数值模拟方法研究了不同的衬垫层结构对于热循环下热障涂层(TBCs)应力分布的影响。首先选取高温镍基合金为基体，NiCrAlY为衬垫层，氧化钇稳氧化锆为隔热层。进而建立二文的热障涂层模型，包括传统衬垫结构、理想网状衬垫结构、实际网状衬垫结构、复合衬垫结构，计算在热循环载荷作用下的热障涂层残余应力的分布。结果表明：冷却过程中，传统衬垫结构TBCs中陶瓷层的收缩导致涂层边缘处产生较大横向残余拉应力和纵向残余压应力，形成垂直表面裂纹,容易使涂层在边缘处破碎剥落；理想网格状衬垫结构可以降低边缘处的残余应力，但由于棱角的存在会导致网格衬垫附近产生较大应力集中；依据实际网状衬垫结构将棱角做钝化处理，改善了网格衬垫附近应力集中的状况；在实际网状衬垫层与基体之间加入层状衬垫层，构成复合衬垫结构，可以进一步改善网格衬垫附近应力集中的状况，而且能够提高基体的抗氧化性能。19934
关键词热障涂层有限元法热循环残余应力
毕业论文设计说明书（论文）外文摘要
Title Numerical simulation of residual stress field of thermal barrier coatings during thermal cycling
Abstract
In this paper, the finite element numerical simulation method has been used to study the distributions of residual stresses of Thermal Barrier Coatings (TBCs) with different structure during thermal cycling. Firstly, the TBCs have three component: substrate(high temperature Nickel-base Alloy), bond layer(NiCrAlY), insulating layer(Yttria stabilized Zirconia). Then a two-dimensional model of thermal barrier coatings is established，including the traditional structure, the ideal reticular structure, actual reticular structure and composite structure. Finally, the influence of the distributions of residual stresses of TBCs during thermal cycling on the performance of coating is investigated. The results show that the shrinkage of ceramic coating with traditional structure lead to a large horizontal and vertical residual stresses and form a vertical surface cracks at the edge of TBCs. Therefore, TBCs will fracture easily. With ideal reticular structure the residual stresses at edges is reduced. But the prisms of the reticular structure will lead to a strong concentration of stress. The decrease of the sharp shape of ideal reticular structure will improve this situation. Adding a layer between actual reticular structure and substrate can improve the concentration of stress and enhance the capacity of oxidation resistance.
Keywords thermal barrier coatings finite element method thermal cycling   residual stress
目   录
1 绪论    1
1.1 热障涂层概述    1
1.2 热障涂层的研究现状    1
1.3 有限元方法及ANSYS软件介绍    7
1.4 本文的主要内容    9
2 具有传统衬垫结构的热障涂层    10
2.1 物理模型    10
2.2 材料参数    11
2.3 边界条件    12
2.4 结果分析    12
3 具有理想网状衬垫结构的热障涂层    16
3.1 物理模型及条件设定    16
3.2 结果分析    16
4 具有实际网状衬垫结构的热障涂层    20
4.1 物理模型及条件设定    20
4.2 结果分析    20
5 具有复合衬垫结构的热障涂层    24
5.1 物理模型及条件设定    24 热循环下热障涂层应力的数值模拟:http://www.751com.cn/cailiao/lunwen_11515.html