A damage mechanics-based fatigue life prediction method for TC4 components considering combined influence of scratch defects and structural geometric features
Xulong Chen , Weiping Hu , Yicun Zeng , Jian Li , Di Zhang , Zhixin Zhan , Qingchun Meng
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引用次数: 0
Abstract
Aircraft structural components may suffer surface scratches during manufacturing or service. In this study, fatigue tests were conducted on TC4 titanium alloy specimens with scratch defects to investigate the influence of scratch depth on fatigue life. Based on continuum damage mechanics and the fatigue damage evolution law of scratch-free materials, an equivalent fatigue damage model was developed, which incorporates the effect of surface scratches while avoiding complex finite element simulations and significantly reducing computational effort. To account for the combined influence of scratch defects and local geometric features, the model was further enhanced by incorporating stress gradient effects and multiaxial equivalent stress. Multiaxial fatigue tests on open-section scratched TC4 titanium alloy tubes were conducted to validate the enhanced model, and the predicted results show good agreement with the experimental data. The methodology enables direct fatigue life estimation of scratched components based on stress analysis of scratch-free counterparts, eliminating the need for complex local stress field analysis around scratches and demonstrating significant advantages for engineering applications.
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.