High cycle tensile fatigue behavior of steel rebar reinforced - UHPFRC at high R-ratio

IF 5.7 2区材料科学 Q1 ENGINEERING, MECHANICAL

International Journal of Fatigue Pub Date : 2024-12-04 DOI:10.1016/j.ijfatigue.2024.108749

Jian Zhan, Alain Nussbaumer, Eugen Brühwiler

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Abstract

This paper investigates the high cycle tensile fatigue behavior of steel rebar reinforced − UHPFRC elements, at a fatigue load ratio, i.e., R-ratio of 0.3, representative for structural applications. Prior to testing, magnetoscopy is conducted on each specimen to determine the local fiber orientation and volume inside UHPFRC. During testing, global specimen deformation is recorded by displacement transducers; specimen surface is monitored by digital image correlation; and strain along rebars inside the specimen is measured by fiber-optic sensors. Based on the test results, an S-N diagram with a high regression coefficient is obtained. Hereby, the normalized fatigue force S is defined as the ratio between the maximum fatigue force and the estimated specimen ultimate tensile resistance. The fatigue endurance limit is identified as being about S = 0.40. It is found that fatigue deformation of the specimen mainly occurs in the zones with low fiber orientation coefficient μ0,y of UHPFRC (μ0,y decreases when average angle between fiber axis and principle tensile direction changes from 0° to 90°), where the strain along steel rebars also have their higher value and increase rates during fatigue testing. The lowest UHPFRC fiber orientation determines the locus of crack localization and of fatigue fracture of steel rebars, thus final fracture of the elements.

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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.