| TGO及初始裂纹对热障涂层裂纹形核与扩展影响的有限元分析 |
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| 引用本文： | 李佐君,梁伟,钟舜聪,戴晨煜.TGO及初始裂纹对热障涂层裂纹形核与扩展影响的有限元分析[J].失效分析与预防,2021,16(5):300-308, 313. |
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| 作者姓名： | 李佐君 梁伟 钟舜聪 戴晨煜 |
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| 作者单位： | 福州大学 机械工程及自动化学院 光学太赫兹及无损检测实验室,福州 350108 |
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| 基金项目： | 国家自然科学基金;机械系统与振动国家重点实验室开放基金;上海市自然科学基金;福建省质监局科技项目 |
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| 摘 要： | 针对热障涂层系统裂纹的形核位置变化与扩展失效过程及其机理，提出采用内聚力单元分析热氧化物（TGO）层/陶瓷（TC）层界面裂纹的形核位置及扩展，采用扩展有限元法分析TGO层厚度、粗糙度以及TC初始裂纹对新TC、TGO裂纹形核位置及扩展的影响。结果表明:TGO/TC界面承受热循环载荷后，界面裂纹首先出现在近波峰处同时向两侧扩展；在冷却过程中，随着TGO初始厚度增加，TC裂纹的形核位置由波峰转向近波峰处而裂纹扩展长度没有明显变化，TGO裂纹形核位置不变但裂纹长度明显增加；随着TGO粗糙度的不断减小，TC裂纹形核位置由近波峰向中部转移，而裂纹扩展长度没有明显变化。当粗糙度减小到一定程度，TC裂纹被抑制。而TGO裂纹的形核位置没有变化，但裂纹扩展长度随着TGO粗糙度减小而增大；初始横向TC裂纹越长，TGO裂纹也越长。近波峰与中部的初始竖直TC裂纹能有效地抑制新的TC裂纹形核与扩展。本研究为热障涂层微裂纹失效机理提供了理论支撑。
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| 关 键 词： | 热障涂层 内聚力单元 扩展有限元 热氧化层 裂纹 |
| 收稿时间： | 2021-05-27 |
Influence of TGO and Initial Crack on Crack Nucleation and Propagation in Thermal Barrier Coatings Based on Finite Element Analysis |
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| LI Zuo-jun,LIANG Wei,ZHONG Shun-cong,DAI Chen-yu.Influence of TGO and Initial Crack on Crack Nucleation and Propagation in Thermal Barrier Coatings Based on Finite Element Analysis[J].Failure Analysis and Prevention,2021,16(5):300-308, 313. |
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| Authors: | LI Zuo-jun LIANG Wei ZHONG Shun-cong DAI Chen-yu |
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| Abstract: | Aiming at the change of nucleation position and propagation failure process and mechanism of cracks in thermal barrier coating system, the cohesive element was used to analyze the nucleation location and propagation of the interface cracks of the thermal growth oxide/top-coat (TGO/TC). The extended finite element method was used to analyze the effects of the thickness and roughness of TGO and the initial crack of TC on the nucleation location and propagation of the new TC crack and TGO crack. The results demonstrated that the cracks at the TGO/TC interface first appear at the off-peak after being subjected to thermal cycling loads. During the cooling process, as the initial TGO thickness increased, the nucleation position of the TC crack shifted from the peak to off-peak without significant change in the crack length. The nucleation position of the TGO crack remained unchanged but the crack length increased significantly. With the decrease of TGO roughness, the nucleation position of TC crack shifted from the off-peak to the middle and was finally constrained, however, the crack length did not change significantly. The nucleation position of TGO crack did not change significantly, but the crack length increased with the decrease of TGO roughness. Furthermore, the longer the initial transverse TC crack, the longer the TGO crack. The initial vertical TC crack near off-peak and middle can effectively constrain the nucleation and propagation of the new TC crack. It could provide the finite element model for investigation of failure mechanism of thermal barrier coatings. |
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