Mechanical and Surface Geometric Properties of Reinforcing Bars and Their Significance for the Development of Near-Surface Notch Stresses

Stefan Rappl (), Muhammed Zubair Shahul Hameed, Christian Krempaszky and Kai Osterminski
Additional contact information
Stefan Rappl: TUM School of Engineering and Design, Department of Materials Engineering, Centre for Building Materials, Technical University of Munich, 81245 Munich, Germany
Muhammed Zubair Shahul Hameed: TUM School of Engineering and Design, Department of Materials Engineering, Institute of Materials Science, Technical University of Munich, 85748 Garching, Germany
Christian Krempaszky: TUM School of Engineering and Design, Department of Materials Engineering, Institute of Materials Science, Technical University of Munich, 85748 Garching, Germany
Kai Osterminski: TUM School of Engineering and Design, Department of Materials Engineering, Centre for Building Materials, Technical University of Munich, 81245 Munich, Germany

Mathematics, 2023, vol. 11, issue 8, 1-15

Abstract: Due to the production process, reinforcing steel bars possess an inhomogeneous microstructure associated with different material properties over the cross-section (e.g., hardness, ductility or strength). Furthermore, the surface required for the bond has a negative effect on the fatigue behavior. The first investigations were carried out in the 1970s and detected the fillet radius r as a key influencing factor. Until now, few studies had been carried out that investigate the quantification of the surface properties on the fatigue behavior, and none of them compared these properties with the local strengths of the material. The current paper presents the first results of a reverse-engineered reinforcing steel bar based on a previously performed laser scanning process. The rebar models were used to calculate the notch stress factors for different diameters based on von Mises stresses taken from FEM simulations. The notch stress factors showed a functional relationship with the fillet radius, which was already shown in the literature. Further experimental investigations on the fatigue and tensile behavior of the structural components in the investigated Tempcore ® rebars were carried out on microstructure specimens eroded by WEDM. The results of the tensile tests were used to derive a yield and tensile strength distribution in the cross-section. Depending on the microstructure, a yield strength between 415 N/mm 2 (ferrite/pearlite core) and 690 N/mm 2 (tempered martensite surface) was found. The acting notch stresses show a logarithmic dependency of the fillet radius, but do not reach the material strength of the surface.

Keywords: reinforcing steel bar; Tempcore ®; microstructure; surface topography; 3D FEM (search for similar items in EconPapers)
JEL-codes: C (search for similar items in EconPapers)
Date: 2023
References: View complete reference list from CitEc
Citations:

Downloads: (external link)
https://www.mdpi.com/2227-7390/11/8/1910/pdf (application/pdf)
https://www.mdpi.com/2227-7390/11/8/1910/ (text/html)

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:gam:jmathe:v:11:y:2023:i:8:p:1910-:d:1126253

Access Statistics for this article

Mathematics is currently edited by Ms. Emma He

More articles in Mathematics from MDPI
Bibliographic data for series maintained by MDPI Indexing Manager ().