疲劳裂通过一个洞的传播
Diogo Neto1, Joel Jesus1, Ricardo Branco1
1University Coimbra, Centre for Mechanical Engineering, Materials and Processes (CEMMPRE), Department of Mechanical Engineering, 3030-788 Coimbra, Portugal.
Materials (Basel, Switzerland)
|January 8, 2025
概括
预测停止孔钻探后的疲劳寿命对于组件安全至关重要. 本研究提出了一种经过验证的方法,用于准确估计孔组件的裂纹启动和传播寿命,从而增强结构完整性的评估.
科学领域:
- 材料科学 材料科学 材料科学
- 机械工程 机械工程
- 断裂力学 断裂力学 断裂力学
背景情况:
- 停止孔技术对于延长破裂组件的疲劳寿命至关重要.
- 精确预测钻探后的疲劳寿命对于确保结构安全至关重要.
- 现有的方法需要改进,以预测在停止孔周围的裂行为.
研究的目的:
- 开发和验证策略,精确预测疲劳裂的启动和传播寿命后一个停止洞.
- 调查关键距离理论和史密斯-沃森-托珀参数对裂启动寿命估计的有效性.
- 采用节点释放策略来计算基于循环塑性变形的疲劳裂增长 (FCG) 率.
主要方法:
- 对7050-T7451合金的紧张型 (CT) 样品进行实验测试,具有3毫米的阻塞孔.
- 使用关键距离理论和史密斯-沃森-托珀参数进行裂纹启动寿命预测.
- 通过节点释放策略计算疲劳裂增长率 (FCG),模拟累积塑料应变.
主要成果:
- 在停止孔后重新启动裂需要625,000个负载周期.
- 临界距离理论给出了31.83μm的临界距离 (El Haddad参数).
- 预测的裂纹启动寿命在实验值的4%以内,对FCG率 (da/dN) 有很好的协议.
结论:
- 拟议的方法准确地预测了具有停止孔的组件中疲劳寿命的启动和传播阶段.
- 这种方法增强了受疲劳负荷影响的有隙元件的安全评估.
- 该研究验证了使用临界距离概念和基于塑料应变的模型来预测疲劳寿命.
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