On material immanent ratchetting of two-phase materials under cyclic purely thermal loading
On material immanent ratchetting of two-phase materials under cyclic purely thermal loading
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循环纯热载荷下两相材料的材料固有棘轮效应
DOI：
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发表时间：
1999
期刊：
影响因子：
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通讯作者：
P. Uggowitzer
中科院分区：
文献类型：
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作者：
V. Silberschmidt;F. Rammerstorfer;E. Werner;F. Fischer;P. Uggowitzer
本文分析了具有不同相热力性能的两相材料对纯热循环响应的具体特征。这表明，即使没有机械载荷，安定和棘轮制度都是可能的。简要介绍了循环热机械载荷下的安定和棘轮现象和各种模型。讨论了描述双相不锈钢这种特殊的两相材料在纯热载荷作用下的三种结构模型：简单的两杆模型、复合圆柱模型和具有双相拓扑结构的微力学有限元模型。这些模型反映了热循环过程中变形过程的不同特征，可作为热棘轮分析的基础。给出了各种材料条件和建模方案的数值模拟结果。推导了材料固有棘轮的条件，并通过数值实验进行了验证。结果表明，在循环热负荷的温度区间内，两相屈服应力的温度依赖性表现为相应曲线的交点，从而加强了这种棘轮效应，而缺乏屈服应力-温度曲线的交点则表明材料内在棘轮效应较少或缺乏。并与室内实验结果进行了比较，验证了微观力学模型推导的趋势。
Summary The paper analyses specific features of the response of two-phase materials with different thermomechanical properties of the phases to purely thermal cycling. It is shown that even without mechanical loading both shakedown and ratchetting regimes are possible. A short review is given of the phenomena and various models of shakedown and ratchetting under cyclic thermomechanical loading. Three structural models for the description of a special two-phase material, namely the duplex stainless steel, under purely thermal loading are discussed: a simple two-bar model, a composite cylinder model and micromechanical finite element models with duplex topologies. These models account for different features of the deformation process during thermal cycling and are used as basis for the analysis of thermal ratchetting. Results of numerical simulations are presented for various material conditions and modelling schemes.Conditions for material immanent ratchetting are derived and verified by numerical experiments. It is shown that a temperature-dependence of the yield stresses of the two phases, which exhibits an intersection of the corresponding curves within the temperature interval of the cyclic thermal load, enforces this sort of ratchetting, lacking intersection of the yield stress-temperature curves indicates, on the other hand, a lesser or lacking tendency for material immanent ratchetting. Comparisons with results of laboratory experiment are also presented, and the tendencies derived from the micromechanical models are verified.