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題 名 | 短疲勞裂紋萌生和擴展的壽命預測=Lifetime Prediction on Short Fatigue Crack Initiation and Propagation |
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作 者 | 胡志忠; 曹淑珍; | 書刊名 | 材料科學 |
卷 期 | 31:2 1999.06[民88.06] |
頁 次 | 頁100-106 |
分類號 | 440.2 |
關鍵詞 | 顯微裂紋; 疲勞裂紋擴展速率; 疲勞壽命預測; Microcrack; Fatiguc crack propagation rate; Fatigue lifetime prediction; |
語 文 | 中文(Chinese) |
中文摘要 | 在應變疲勞範圍內,裂紋萌生和擴展的力學參量是應變強度因子範圍,利用這一 參量和 效裂紋尖端張開位移模型建立了顯微裂紋在疲勞裂紋非連續擴展和連續擴展階段的速度與壽 命同基本力學性能之間的關係。 在 da/dN 公式中應變範圍的指數為 2,常數為斷裂應變平 方的倒數。 若將其中的應變用應力的 1/n 次方代替,就變成應力疲勞的速率公式。在零平 均應力狀態下,利用這些公式和基本力學性能預測應變低周疲勞和應力高周疲勞的裂紋萌生 與擴展壽命,其結果十分令人滿意。 |
英文摘要 | In the range of strain fatigue, the mechanics parameter for the fatigue crack initation and propagation is the strain intensity factor range. Using this parameter and the model on available crack tip opening displacement, it is produced that the relation between the fatigue crack propagation rate (da/dN) and the basic mechanics property for short crack and micro structure short crack in the phases of crack propagation for the non-continuous and continuous. For strain fatigue the exponent of strain range (△ε )in da/dN equation equals 2, i.c. (△ε�� ), and the coefficient in da/dN equation is reciprocal of the square of fracture strain, i.e. 1/ ε. For stress fatigue if only the item (△ε / ε ) �� is changed into (σ / σ ) in the da/dN equation, where n is the hardening exponent and σ is the fracture true stress. The equation of fatigue lifetime prediction is only integrated the relation of da/dN. The results of fatigue lifetime prediction by means of the basic mechanics behavior for low cycle fatigue and high cycle fatigue are very satisfactory. |
本系統中英文摘要資訊取自各篇刊載內容。