Fatigue life prediction methodology for welded joints considering defect effects

IF 6.8 2区材料科学 Q1 ENGINEERING, MECHANICAL

International Journal of Fatigue Pub Date : 2025-10-07 DOI:10.1016/j.ijfatigue.2025.109307

Xiaogang Liu , Pinzhou Zhu , Zhenmin Qian , Sihui Yang

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Abstract

The paper focuses on defect detection, quantitative characterization, and fatigue crack growth life prediction considering defect effects for 1Cr11Ni2W2MoV argon arc-welded joints used in engine combustion chamber casings. First, X-CT technology was used to detect microscopic defects in different weld zones. Through three-dimensional defect reconstruction, the defect sizes and distribution patterns in various weld regions were quantitatively characterized. The maximum characteristic defect sizes were predicted using extreme value statistical analysis. Subsequently, based on fatigue crack growth test data analysis of welded joint heat-affected zones, a NASGRO equation describing the complete crack growth process in welded joints was established. Based on these findings, the model was further modified by incorporating variations in threshold values and closure parameters during short crack growth. By combining defect morphology, size characteristics, and extreme value statistical analysis results, defects were equivalently treated as semi-elliptical cracks to calculate the fatigue life of joints under different stress levels. Comparative analysis with experimental results demonstrated that the predicted lives from the modified model all fell within a factor of two scatter band, indicating its practical significance for fatigue life assessment of welded joints considering defect effects. Furthermore, the modified model was applied to extend the conventional stress-defect model (K-T diagram), establishing a stress-defect-life diagram that enables fatigue life evaluation of welded joints with various initial defect sizes under different stress conditions.

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考虑缺陷影响的焊接接头疲劳寿命预测方法

本文主要研究了发动机燃烧室壳体用1Cr11Ni2W2MoV氩弧焊接头的缺陷检测、定量表征和考虑缺陷影响的疲劳裂纹扩展寿命预测。首先，利用X-CT技术检测不同焊接区域的微观缺陷；通过三维缺陷重建，定量表征了焊缝各区域缺陷的尺寸和分布规律。利用极值统计分析预测了最大特征缺陷尺寸。随后，在对焊接接头热影响区疲劳裂纹扩展试验数据分析的基础上，建立了描述焊接接头裂纹扩展全过程的NASGRO方程。基于这些发现，该模型被进一步修正，纳入了短裂纹扩展过程中阈值和闭合参数的变化。结合缺陷形态、尺寸特征及极值统计分析结果，将缺陷等效处理为半椭圆裂纹，计算不同应力水平下接头的疲劳寿命。与试验结果对比分析表明，修正模型的预测寿命均落在两个散射带的因子范围内，说明修正模型对考虑缺陷影响的焊接接头疲劳寿命评估具有实际意义。将修正后的模型扩展到传统的应力-缺陷模型（K-T图），建立了应力-缺陷-寿命图，可以对不同初始缺陷尺寸的焊接接头在不同应力条件下进行疲劳寿命评估。

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

International Journal of Fatigue 工程技术-材料科学：综合

CiteScore

10.70

自引率

21.70%

发文量

619

审稿时长

58 days

期刊介绍： Typical subjects discussed in International Journal of Fatigue address: Novel fatigue testing and characterization methods (new kinds of fatigue tests, critical evaluation of existing methods, in situ measurement of fatigue degradation, non-contact field measurements) Multiaxial fatigue and complex loading effects of materials and structures, exploring state-of-the-art concepts in degradation under cyclic loading Fatigue in the very high cycle regime, including failure mode transitions from surface to subsurface, effects of surface treatment, processing, and loading conditions Modeling (including degradation processes and related driving forces, multiscale/multi-resolution methods, computational hierarchical and concurrent methods for coupled component and material responses, novel methods for notch root analysis, fracture mechanics, damage mechanics, crack growth kinetics, life prediction and durability, and prediction of stochastic fatigue behavior reflecting microstructure and service conditions) Models for early stages of fatigue crack formation and growth that explicitly consider microstructure and relevant materials science aspects Understanding the influence or manufacturing and processing route on fatigue degradation, and embedding this understanding in more predictive schemes for mitigation and design against fatigue Prognosis and damage state awareness (including sensors, monitoring, methodology, interactive control, accelerated methods, data interpretation) Applications of technologies associated with fatigue and their implications for structural integrity and reliability. This includes issues related to design, operation and maintenance, i.e., life cycle engineering Smart materials and structures that can sense and mitigate fatigue degradation Fatigue of devices and structures at small scales, including effects of process route and surfaces/interfaces.