Z.Z.Lǖ
金属学报(英文版)
A numerical simulation method is presented for the random-fuzzy safety analysis of an aero engine disk. Based on the equivalent transformation from a fuzzy variable to a random variable, the equivalent random Probability Density Functions(PDFs) are got from their corresponding Fuzzy Possibility Distributions(FPDs) for the fuzzy variables. In that case the perfect numerical simulation method for the random uncertainty is employed to solve the fuzzy uncertainty. For the complex structure such as the aero engine disk with implicit relationship between the input basic variable and the response variable, the equivalent PDFs of the input basic variables are delivered simultaneously to the response variable by an empirical PDF, which is simulated by Finite Element Method(FEM). Then, in view of the fuzzy application requirement occurring in engineering usually, the reliability definition and calculation are discussed for the aero engine disk with multiple fuzzy failure modes. On the other hand, through the inverse transformation of the fuzzy variable to the random variable, the FPDs of the response variables can be calculated from their empirical PDFs as well.
关键词:
random
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null
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null
周灿
,
周储伟
,
何乾强
复合材料学报
通过类比复合材料湿扩散与热传导的控制方程以及边界条件,以Halpin&Tsai模型为基础,发展了一个考虑了纤维/基体界面相的三相复合材料湿扩散模型,并研究了纤维界面随机损伤对湿扩散的影响.建立了纤维周期排布、随机排布、界面相损伤随机分布3种细观有限元模型.用上述模型分析了单向复合材料横向有效湿扩散系数(TEMDUC)随纤维和界面相体积分数、湿扩散性能以及界面相损伤率变化的规律,理论预测与有限元计算结果一致.研究发现:界面相或纤维相的扩散系数存在一个临界值,当扩散系数小于该临界值时,TEMDUC随纤维体积分数的增大而减小;反之,TEMDUC随纤维体积分数的增大而增大,此临界值的大小与纤维体积含量无关.研究还发现纤维界面损伤率相同的条件下,其分布的随机性对复合材料的有效湿扩散系数影响不大.
关键词:
复合材料
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有效湿扩散系数
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界面相损伤
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随机
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概率密度
