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形状记忆合金是由马氏体相和奥氏体相组成的非均质材料,热力载荷及相变不可避免地在材料中引起残余微应力场,它与外界驱动力的叠加可能导致低应力水平下发生马氏体相变或逆相变.论文假设马氏体相变及逆相变的驱动力是马氏体体积分数的连续函数,发展了形状记忆合金伪弹性的本构描述及相应的数值分析方法.分析表明,所发展的方法与理想相变模型间的误差远小于已有工作中引入的容许误差.对形状记忆合金单晶伪弹性响应的计算结果与试验结果或已有模型计算结果的比较表明所发展的方法具有较高的精度.此外,所发展的方法具有明晰的物理背景,且无需对每个变体的相变发生与否及其方向进行判断,简化了计算过程,提高了计算效率和收敛性.
Shape memory alloys are heterogeneous materials composed of a martensite phase and an austenite phase. Thermal loads and phase transitions inevitably cause residual micro-stress fields in the material, and their superimposition with external driving forces can lead to low stress levels Martensitic transformation occurs under the phase transition or reverse phase.We hypothesized that the driving force martensitic transformation and reverse phase transformation is a continuous function of martensite volume fraction of shape memory alloy pseudo-elastic constitutive description and the corresponding Numerical analysis method.The analysis shows that the error between the developed method and the ideal phase transition model is far less than the allowable error introduced in the existing work.The calculation results and the experimental results of the pseudo-elastic response of the shape memory alloy single crystal or the existing model calculation The comparison of the results shows that the developed method has high precision.In addition, the developed method has a clear physical background, and does not need to judge whether the phase transition of each variant occurs or not and its direction, simplifies the calculation process, Improve computational efficiency and convergence.