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在半圆柱型氧化模式的基础上,建立了具有SiC涂层C/C复合材料在湿氧环境中的疲劳失效模型。在高温湿氧环境下,C/C复合材料的疲劳失效主要受到氧化深度的控制,而影响氧化深度的主要参数是涂层表面裂纹的宽度。对此疲劳失效模型,讨论分析实验温度以及外加应力对裂纹宽度的影响,考虑了疲劳载荷引起的材料模量变化对裂纹宽度的影响。在90、105、120、135和150 MPa疲劳应力下的材料在1300℃湿氧环境中的平均寿命分别为48660、32645、22078、12332和4786循环。进行了实验数据与模型计算值的对比,实测寿命与预测结果吻合良好。另外,本模型在外加应力较大、实验时间较短条件下的预测数据与实验结果最为接近。
Based on the semi-cylindrical oxidation model, a fatigue failure model of SiC-coated C / C composites in a wet-oxygen environment was established. The fatigue failure of C / C composites is mainly controlled by the depth of oxidation under the condition of high temperature and humidity. The main parameter affecting the depth of oxidation is the width of the surface cracks. In this fatigue failure model, the influence of experimental temperature and applied stress on crack width is discussed, and the effect of fatigue load on the crack width is considered. The average lifetimes of materials under fatigue stress of 90, 105, 120, 135 and 150 MPa in the 1300 ° C wet-oxygen environment are 48660, 32645, 22078, 12332 and 4786 cycles, respectively. The experimental data and the calculated values of the model are compared, and the measured life is in good agreement with the predicted results. In addition, the model in the external stress larger, shorter experimental conditions, the predicted data and the experimental results closest to.