Notch fatigue life prediction in metals: A critical distance model with microstructure and geometry effects

IF 5.6 2区工程技术 Q1 ENGINEERING, MECHANICAL

Theoretical and Applied Fracture Mechanics Pub Date : 2025-09-01 DOI:10.1016/j.tafmec.2025.105213

Xing Yang, Panpan Wu, Zhonghong Dong

引用次数: 0

Abstract

Fatigue assessment of engineering components under cyclic loading must particularly account for the combined influence of notch and microstructural effects on failure mechanisms. This study develops a relative stress gradient (RSG)-based critical distance approaches for predicting fatigue life in notched metallic components. The core innovation involves integrating Atzori-Lazzarin (A-T) diagram analysis with short-crack transition concepts. This integration enables the derivation of an analytical expression for the RSG that inherently quantifies the synergistic effects of both macroscopic notch dimensions and average grain size, based on this, a novel reformulation of critical distance theory is propose. Systematic validation using fatigue test data from representative notched specimens of EN3B, Al alloy 2024, and TC4 materials demonstrates excellent agreement between predicted and experimental lifetimes, confirming the model’s improved predictive capability.

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金属缺口疲劳寿命预测：具有微观结构和几何效应的临界距离模型

工程构件在循环载荷作用下的疲劳评估必须特别考虑缺口效应和微结构效应对失效机制的综合影响。本研究提出了一种基于相对应力梯度（RSG）的临界距离方法来预测缺口金属部件的疲劳寿命。核心创新是将Atzori-Lazzarin （A-T）图分析与短裂纹转换概念相结合。这种整合可以推导出RSG的解析表达式，该表达式固有地量化了宏观缺口尺寸和平均晶粒尺寸的协同效应，在此基础上，提出了一种新的临界距离理论的重新表述。利用EN3B、2024铝合金和TC4等材料的代表性缺口试样的疲劳试验数据进行了系统验证，结果表明，预测寿命与实验寿命非常吻合，证实了模型预测能力的提高。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Theoretical and Applied Fracture Mechanics 工程技术-工程：机械

CiteScore

8.40

自引率

18.90%

发文量

435

审稿时长

37 days

期刊介绍： Theoretical and Applied Fracture Mechanics'' aims & scopes have been re-designed to cover both the theoretical, applied, and numerical aspects associated with those cracking related phenomena taking place, at a micro-, meso-, and macroscopic level, in materials/components/structures of any kind. The journal aims to cover the cracking/mechanical behaviour of materials/components/structures in those situations involving both time-independent and time-dependent system of external forces/moments (such as, for instance, quasi-static, impulsive, impact, blasting, creep, contact, and fatigue loading). Since, under the above circumstances, the mechanical behaviour of cracked materials/components/structures is also affected by the environmental conditions, the journal would consider also those theoretical/experimental research works investigating the effect of external variables such as, for instance, the effect of corrosive environments as well as of high/low-temperature.