Influence of material models on the stress state in thermal barrier coating simulations
Influence of material models on the stress state in thermal barrier coating simulations
复制标题
DOI：
10.1016/j.surfcoat.2013.12.045
复制
发表时间：
2014-02
影响因子：
5.4
通讯作者：
M. Bäker
中科院分区：
文献类型：
--
作者：
M. Bäker
热障涂层系统的应力状态和失效机制经常使用有限元模拟进行研究。评估此类模拟结果的一个问题是，顶涂层的材料行为，尤其是热生长氧化物的材料行为尚不清楚。通常认为塑性或粘塑性是主要的应力松弛机制，隐含的假设是这两种机制都会导致类似的应力模式。在这篇文章中，这个假设得到了严格的评估。研究了面漆和 TGO 的塑性或粘塑性的不同组合。如果不存在粘塑性，则应力演变以塑性棘轮作用为主，但如果蠕变强度足够低，则可以通过蠕变松弛来抵消。
The stress state and failure mechanisms of thermal barrier coating systems are frequently studied using finite element simulations. One problem in evaluating the results of such simulations is that the material behaviour of the top coat and especially of the thermally grown oxide is not well-known. Either plasticity or viscoplasticity is frequently assumed to be the dominating stress relaxation mechanism with the implicit assumption that both mechanisms will lead to similar stress patterns. In this contribution, this assumption is critically evaluated. Different combinations of plasticity or viscoplasticity for the top coat and the TGO are studied. If viscoplasticity is not present, the stress evolution is dominated by plastic ratchetting, but this is counteracted by creep relaxation if the creep strength is sufficiently low.