重新抽樣法於分析金屬疲勞裂縫成長行為之應用

• Main Authors: Tsu-Yi Cheng, 鄭子議
• Other Authors: 吳文方
• Format: Others
• Language: zh-TW
• Published: 2005
• Online Access: http://ndltd.ncl.edu.tw/handle/18107844354196758013

碩士 === 國立臺灣大學 === 機械工程學研究所 === 91 === Considering the randomness of fatigue crack growth of metals, some researchers proposed to describe the crack growth curves by statistical methods. For example, one can fit parameters describing the fatigue crack growth rate by certain kinds of probability distributions. The best-fitted distribution functions can be determined through statistical tests. However, the following two problems remained. Firstly, even the best-fitted function is not enough to describe the real fatigue crack growth result. Secondly, different best-fitted functions may be derived for different experiment data sets. To resolve these problems, two kinds of statistical resampling methods are employed in this thesis in order to find more exact probability distributions of these random parameters. It is assumed that the randomness of fatigue crack growth curves is due to the uniqueness of each individual specimen. Thus, the derived parametric distributions reflect the mother property of all specimens under the same loading. For a certain specimen having a certain crack size observed, a method is proposed to narrow-down the finding of more appropriate parametric distributions that can describe the unique specimen more exactly. The result can accordingly provides us more exact fatigue crack growth prediction as well as its reliability assessment.