Jun Cao , Feixiang Weng , Shuquan Zhang , Huaming Wang , Jikui Zhang
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引用次数: 0
Abstract
The notch, such as hole and chamfer, is unavoidable for aircraft structural components. Stress concentration induced by notch is the leading cause of fatigue failure. It is significant for structural integrity and safety assessment to clarify the intrinsic mechanism causing the difference in fatigue notch sensitivity. The notch fatigue fracture behavior of TC11 samples, fabricated by laser direct energy deposited (LDED) and wrought processes, is studied by high cycle fatigue (HCF) tests, fracture morphology, systematic microstructural characterizations, and theoretical analysis. HCF test results show that the notch fatigue performance of LDED samples reported in this study is superior to that of the wrought ones. The modified critical radius calculated from the equivalent material concept and average strain energy density criterion correlates well with fatigue notch sensitivity q and notch fatigue performance. The thick lamellar α phase produces more crack resistance and higher local plasticity around the notch root, causing lower q of LDED samples. Besides, the difference in q caused by build orientations is attributed to the variations in the angle between the c-axis of the fiber texture and load direction, the dominant slip system, the boundaries between soft and hard grains, and the presence of prior β grain boundaries.
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.
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