文章信息/Info

Title:

Numerical Simulation of Thermal Barrier Coating Damage Failure Based on the Force�睭eat Equivalence Energy Density Principle

文章編號:

1674-3962(2020)11-0871-07

作者:

李定玉1; 2; 王樹彬2; 徐念東2; 李衛(wèi)國2

（1. 重慶科技學(xué)院建筑工程學(xué)院，重慶 401331）（2. 重慶大學(xué)航空航天學(xué)院，重慶 400030）

Author(s):

LI Dingyu1; 2;  WANG Shubin2;  XU Niandong2;  LI Weiguo2

(1. School of Civil Engineering and Architecture, Chongqing University of Science and Technology, Chongqing 401331, China) (2. College of Aerospace Engineering, Chongqing University, Chongqing 400030, China)

關(guān)鍵詞:

熱障涂層; 失效能密度; 有限元; 損傷; 塑性; 蠕變

Keywords:

thermal barrier coating;  failure energy density;  finite element method;  damage;  plastic;  creep

分類號:

TG174.44

DOI:

10.7502/j.issn.1674-3962.202006035

文獻標(biāo)志碼:

A

摘要:

熱障涂層是保障燃氣輪機渦輪葉片、火箭發(fā)動機在極端高溫有氧環(huán)境服役的核心技術(shù)之一，其損傷失效機理仍然是目前該領(lǐng)域的難點。基于力熱能量密度等效原理并考慮塑性變形能，推導(dǎo)了一個適用于熱障涂層在循環(huán)熱載荷下的溫度相關(guān)性損傷失效判據(jù)，并結(jié)合有限元方法分析了循環(huán)熱載荷下熱障涂層的失效能密度的分布情況，重點討論了陶瓷層(TC)表面升溫、保溫和降溫3個典型階段考慮塑性變形能的失效能密度分布與單純考慮拉伸效應(yīng)彈性應(yīng)變能的失效能密度分布的差異，并對循環(huán)熱載荷條件下熱障涂層的損傷失效行為進行了模擬。結(jié)果表明，造成熱障涂層損傷失效的裂紋并非一直沿著TC/TGO往波谷擴展，并且熱生長氧化層（TGO）波峰頂部不容易產(chǎn)生裂紋，這兩個關(guān)鍵現(xiàn)象與實驗所得結(jié)果吻合，驗證了推導(dǎo)的溫度相關(guān)性損傷失效判據(jù)的準(zhǔn)確性，并克服了基于傳統(tǒng)斷裂力學(xué)的VCCT技術(shù)、Cohesive單元法和擴展有限元法等的局限性，為熱障涂層的強度評估與安全性評價提供了科學(xué)依據(jù)。

Abstract:

Thermal barrier coating (TBC) is one of the essential technologies to ensure the safety of gas turbine blades and rocket engines under the service condition of extremely high temperature and oxidation atmosphere. However, the damage failure mechanism of TBCs is still a challenge in this field. In this paper, a temperature-dependent damage failure criterion for TBCs considering the plastic deformation energy under thermal cycling was proposed based on the force-heat equivalence energy density principle. Meanwhile, combined with the finite element method, the failure energy density distribution in TBCs under thermal cycling was analyzed. The differences of the failure energy density distribution in ceramic top coat (TC) layer during three typical stages as heating, holding and cooling between two different simulations, one considering the plastic deformation energy and the other only with the tensile elastic strain energy were discussed, respectively. Moreover, the damage failure behaviors of TBCs under thermal cycling were simulated. The results showed that the cracks which caused the damage failure of TBCs did not always propagate along the boundary of TC / TGO to the trough, and it was not easy for cracks to appear on the top of the wave crest of TGO layer. These two key phenomena were consistent with the experimental results, which verified the accuracy of the temperature dependent damage failure criterion derived in this paper. The deduced criterion could overcome the limitations involved in VCCT technology, cohesive element method and extended finite element method based on traditional fracture mechanics, and provide a scientific basis for strength and safety evaluation of TBC.