Bridge steel structures are widely used in bridge construction with the advantages of light self-weight, convenient use, and good bridge span. Steel bridges are subjected to cyclic loading for a long time during their service period, and cyclic loading has a certain influence on their fatigue resistance performance. Fatigue is a phenomenon in which the structure is subjected to cyclic loading that generates cracks, expands continuously, and eventually leads to fracture of the member. The bridge steel structure under the repeated action of vehicle load and cyclic load is caused by microcracks and will expand with time, and the bridge deck system structure is prone to fatigue damage, so fatigue fracture detection has a great impact on the safe service life of steel bridges. In this paper, the fatigue design guidelines in the relevant codes and the bridge steel structure detection model are compared and analyzed, and a neural network-based fatigue fracture detection model for bridge steel structures under cyclic loading is proposed for the study of fatigue and corrosion interactions and fatigue and fracture of steel bridges under complex stress conditions. For this purpose, in the relevant experiments, experiments are designed to detect the fatigue fracture of bridge steel structures under different cyclic loads, and the experimental results prove the effectiveness of the proposed method.
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http://dx.doi.org/10.1155/2022/8534824 | DOI Listing |
Materials (Basel)
January 2025
School of Civil Engineering, Nanjing Tech University, Nanjing 211816, China.
The issues of numerous steel beam components and the tendency for deck cracking under negative bending moment zones have long been challenges faced by traditional composite I-beams with flat steel webs. This study introduces an optimized approach by modifying the structural design and material selection, specifically substituting flat steel webs with corrugated steel webs and using ultra-high-performance concrete for the deck in the negative bending moment zone. Three sets of model tests were conducted to compare and investigate the influence of deck material and web forms on the bending and crack resistance of steel-concrete composite I-beams under a negative bending moment zone.
View Article and Find Full Text PDFMaterials (Basel)
January 2025
School of Civil Engineering, Nantong Institute of Technology, Nantong 226000, China.
Adding expansion agents to compensate for concrete shrinkage is a common crack resistance technique, but excessive expansion can also increase the porosity of concrete and reduce its strength. The addition of fibers can reduce expansion and improve the compactness of concrete. However, too little fiber will not be effective in inhibition, while too much fiber will cause aggregation.
View Article and Find Full Text PDFBMC Oral Health
January 2025
Clinic of Masticatory Disorders and Dental Biomaterials, Center for Dental Medicine, University of Zurich, Zurich, Switzerland.
Purpose: The aim of this study was to compare the wear and fracture resistance of single crowns produced from newly developed 3D printer resins used to produce permanent crowns and currently used composite CAD/CAM discs, after being thermomechanically aged in a chewing simulator.
Materials And Methods: A total of 112 stainless steel die models simulating mandibular left first molars were produced, 8 for each group. Single crowns were produced from 3 different discs (Grandio Voco [GR], breCAM HIPC [HC], and Shofu HC [SF]) by CAD/CAM milling method and manufactured from from 4 different permanent composite resins (Nexdent C&B MFH [ND], Permanent Bridge Saremco [PB], VarseoSmile Crownplus [VSC], and Şenertek P-Crown [PC]) using the 3D printing method.
Sci Rep
January 2025
Department of Structural Engineering, Mansoura University, PO BOX 35516, Mansoura, Egypt.
Concrete-filled steel tube (CFST) columns are widely employed in high-rise buildings, long-span bridges, and seismic-resistant structures due to their superior load-bearing capacity, structural efficiency, and resilience under extreme loading conditions. This study uses symbolic regression with structural design code provisions to predict the eccentric strength of concrete filled-steel tubular columns with circular shape (CCFST) and rectangular shape (RCFST). Previous studies have used two distinct approaches for estimating eccentric strength: explainable models based on theoretical derivations and black-box models derived from machine learning (ML) methods.
View Article and Find Full Text PDFHeliyon
January 2025
Advanced Technologies of Machine Tools (ATMT) Lab, Faculty of Mechanical Engineering, Tarbiat Modares University, Tehran, Iran.
Electrochemical grinding (ECG) offers advantages such as burr-free and stress-free material removal. Despite its proven potential, limited research has addressed the comprehensive effects of key process parameters on the surface integrity of AISI 304 stainless steel, particularly for applications requiring high-quality finishes, such as medical components. This study bridges this gap by systematically investigating the influence of ECG key parameters including voltage, rotational speed, and electrolyte concentration on main surface integrity parameters including current density, surface roughness, microhardness, and surface texture.
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