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基于内聚力单元与XFEM的热障涂层失效分析

Failure analysis of thermal barrier coatings based on cohesive element and XFEM

  • 摘要: 为了更好的理解热障涂层的失效机理,文中运用ABAQUS有限元软件来分析热障涂层的失效情况,使用内聚力单元和扩展有限元(XFEM)两种方法研究热障涂层TGO界面开裂与陶瓷涂层(TC)和氧化层(TGO)内随机裂纹的萌生与扩展,研究竖直裂纹与水平裂纹的关系.结果表明,热障涂层TGO界面的开裂首先出现在TGO/TBC波谷处.陶瓷涂层和氧化层内随机裂纹的萌生同样发生在TGO/TBC波谷处.竖直裂纹的存在可以抑制水平裂纹的萌生与扩展,且其在TGO/TBC波谷处的扩展长度比在TGO/TBC波峰处的扩展长度更长,说明TGO/TBC波谷区域是个危险区域,在此区域容易引发裂纹的萌生与扩展.

     

    Abstract: In order to better understand the failure mechanism of the thermal barrier coating, the ABAQUS finite element software was used to analyze the failure of the thermal barrier coating. Cohesive element and extended finite element (XFEM) were used to study the cracking of the TGO interface in the thermal barrier coating and the initiation and propagation of random cracks in the ceramic coating (TC) and the oxidation layer (TGO). The relationship between vertical cracks and horizontal cracks was studied. The results shown that the cracking of the TGO interface of the thermal barrier coating first occurred at the TGO/TBC trough, and the initiation of the random cracks in the ceramic coating and the oxidation layer also occurred at the TGO/TBC trough. The existence of the vertical crack could inhibit the initiation and propagation of the horizontal crack, and the propagation lengths at the TGO/TBC trough was longer than that of the TGO/TBC crest. It indicated that the TGO/TBC trough area was a dangerous area, which was likely to cause crack initiation and propagation in this area.

     

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