不寻常的疲劳裂生长行为长裂在低压力强度因子范围的长裂
Daniel Kujawski1, Asuri K Vasudevan2
1Mechanical and Aerospace Engineering, Western Michigan University, Kalamazoo, MI 49008, USA.
Materials (Basel, Switzerland)
|February 24, 2024
概括
一些合金表现出意想不到的疲劳裂增长 (FCG) 行为,在低应力强度因子范围内缺乏值. 这挑战了对振动下的结构的安全疲劳寿命预测.
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:
- 传统的疲劳裂增长 (FCG) 分析假设裂增长速度 (da/dN) 的单调下降,应力强度因子范围 (ΔK) 的下降,达到值 (ΔKth).
- 这种行为通常以给定R比或Kmax的da/dN ≤10−7mm/周期为特征.
- 本研究回顾了一些合金中观察到的不寻常的FCG行为.
研究的目的:
- 描述和审查某些合金中异常缺乏疲劳值的情况.
- 讨论这种行为对耐损设计方法的影响.
- 为了强调这对疲劳寿命预测模型构成的挑战.
主要方法:
- 对疲劳裂生长 (FCG) 行为的实验观察的审查.
- 在不同的条件下 (da/dN) -ΔK关系的表征.
- 对断裂力学和设计的影响分析.
主要成果:
- 一些合金在da/dN中表现出平原或加速, ΔK下降,这与传统的值行为相反.
- 这种不寻常的行为在恒定的R比和Kmax条件下观察到长裂.
- 这种现象首次被Marci在1996年在IMI 834合金中观察到.
结论:
- 在一些合金中观察到缺乏疲劳值,这挑战了已建立的断裂力学原理.
- 这种现象需要进一步的研究,以了解其潜在的机制.
- 对这种行为进行准确的建模对于在受低振幅振动影响的结构中可靠的疲劳寿命预测至关重要.
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