The premature failure of reinforced concrete (RC) structures is significantly affected by chloride-induced corrosion of reinforcing steel. Although researchers have achieved many outstanding results in the structural capacity of RC structures in the past few decades, the topic of service life has gradually attracted researchers' attention. In this work, based on the stress intensity, two models are developed to predict the threshold expansive pressure, corrosion rate and cover cracking time of the corrosion-induced cracking process for RC structures. Specifically, in the proposed models, both the influence of initial defects and modified corrosion current density are taken into account. The results given by these models are in a good agreement with practical experience and laboratory studies, and the influence of each parameter on cover cracking is analyzed. In addition, considering the uncertainty existing in the deterioration process of RC structures, a methodology based on the third-moment method in regard to the stochastic process is proposed, which is able to evaluate the cracking risk of RC structures quantitatively and predict their service life. This method provides a good means to solve relevant problems and can prolong the service life of concrete infrastructures subjected to corrosion by applying timely inspection and repairs.
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http://dx.doi.org/10.3390/ma14061440 | DOI Listing |
Materials (Basel)
January 2025
Department of Mechanical Engineering, Kunsan National University, Gunsan-si 54150, Republic of Korea.
The key structural components of a wind turbine blade, such as the skin, spar cap, and shear web, are fabricated from fiber-reinforced composite materials. The spar, predominantly manufactured via resin infusion-a process of resin injection and curing in carbon fibers-is prone to initial defects, such as pores, wrinkles, and delamination. This study suggests employing the pultrusion technique for spar production to consistently obtain a uniform cross-section and augment the reliability of both the manufacturing process and the design.
View Article and Find Full Text PDFMaterials (Basel)
January 2025
Department of Mechanical Engineering, Faculty of Engineering, University of Isfahan, Isfahan 817467344, Iran.
Friction stir spot welding (FSSW) technology relies on the generation of frictional heat during the rotation of the welding tool in contact with the workpiece as well as the stirring effect of the tool pin to produce solid-state spot joints, especially for lightweight materials. Although FSSW offers significant advantages over traditional fusion welding, the oxidation of the interfacial bond line remains one of the most challenging issues, affecting the quality and strength of the joint under both static and cyclic loading conditions. In this experimental study, inert argon gas was employed to surround the joint, aiming to prevent or minimize the formation of the interfacial oxides.
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December 2024
School of Materials Science and Engineering, Northwestern Polytechnical University, Xi'an 710072, China.
TC17 titanium alloy is widely used in the aviation industry for dual-performance blades, and linear friction welding (LFW) is a key technology for its manufacturing and repair. However, accurate evaluation of the mechanical properties of TC17-LFW joints and research on their joint fracture behavior are still not clear. Therefore, this paper used the finite element numerical simulation method (FEM) to investigate the mechanical behavior of the TC17-LFW joint with a complex micro-structure during the tensile processing, and predicted its mechanical properties and fracture behavior.
View Article and Find Full Text PDFMaterials (Basel)
December 2024
COMTES FHT a.s., Prumyslova 995, 334 41 Dobrany, Czech Republic.
One of the concepts behind Generation IV reactors is a molten salt coolant system, where the materials for the reactor itself and for the primary and secondary circuit components are subjected to extreme chemical and thermal stresses. Due to the unavailability of these materials, a nickel-molybdenum alloy known as MoNiCr has been developed in the Czech Republic. This paper discusses the manufacturing process for the MoNiCr alloy, covering conventional casting technology, forming, powder atomization, additive manufacturing (AM) using the directed energy deposition (DED-LB) process, and final heat treatment.
View Article and Find Full Text PDFInt J Biol Macromol
December 2024
Department of Materials Science and Engineering, Faculty of Engineering & Technology, Tarbiat Modares Universirty, Tehran, Iran.
One of the most effective ways to solve the problems caused by the presence of steel implants in the body is to apply a coating to them. This study aims to develop and optimize composite coatings of magnesium oxide (MgO), 58S bioactive glass (BG), and N-carboxymethyl chitosan (N-CMC) on stainless steel (SS316L) substrates using the electrophoretic deposition (EPD) method. The synthesized materials were characterized using FTIR, XRD, and SEM to confirm their structure and morphology prior to coating.
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