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Stochastic fatigue crack growth in steel structures subjected to random loading.

机译:钢结构在随机载荷作用下的随机疲劳裂纹扩展。

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摘要

Fatigue crack growth can be a significant problem in steel structures that are subjected to a large number of repeated load cycles during their service lives. Uncertainty in fatigue behavior arises from the random nature of the service load, environmental conditions, material properties and other factors. Stochastic approaches to model this uncertainty can lead to improved fatigue-resistant design or in-service inspection and maintenance policies. This dissertation generalizes the stochastic model of uncertainty in crack growth under constant amplitude loading by introducing a random noise process with arbitrary (generally non-Gaussian) marginal distribution and correlation structure. A computationally efficient method based on the rainflow method of stress cycle identification is proposed for handling broad-band stress processes in analyzing stochastic crack propagation. The impact of uncertainty in flaw detection and measurement capabilities on in-service structural condition assessment and reliability-based service life prediction also is investigated.; The proposed method is applied in a time-dependent reliability analysis of a steel miter gate at the Emsworth Lock and Dam that suffered severe deterioration from corrosion-fatigue. The predicted fatigue behavior is consistent with observations of damage over a sixty-year service life; providing some confirmation of the use of stochastic fatigue analysis in structural condition assessment and service life prediction.
机译:疲劳裂纹扩展在钢结构中可能是一个重大问题,在钢结构的使用寿命中会遭受大量重复的载荷循环。疲劳行为的不确定性是由服务负载,环境条件,材料特性和其他因素的随机性引起的。对这种不确定性进行建模的随机方法可以改善抗疲劳设计或使用中的检查和维护策略。本文通过引入具有任意(通常是非高斯)边际分布和相关结构的随机噪声过程,推广了恒定振幅载荷下裂纹扩展不确定性的随机模型。提出了一种基于雨流应力循环识别的高效计算方法,用于分析随机裂纹扩展中的宽带应力过程。还研究了缺陷检测和测量能力的不确定性对在役结构状态评估和基于可靠性的使用寿命预测的影响。该方法应用于因腐蚀疲劳而严重恶化的Emsworth Lock和Dam的钢斜切门的时变可靠性分析。预计的疲劳行为与观察到的使用寿命超过60年一致;证实了随机疲劳分析在结构状态评估和使用寿命预测中的使用。

著录项

  • 作者

    Zheng, Ruohua.;

  • 作者单位

    The Johns Hopkins University.;

  • 授予单位 The Johns Hopkins University.;
  • 学科 Engineering Civil.
  • 学位 Ph.D.
  • 年度 1998
  • 页码 173 p.
  • 总页数 173
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 建筑科学;
  • 关键词

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