The efficiency of fibre reinforcement in concrete can be drastically increased by orienting the fibres using a magnetic field. This orientation occurs immediately after pouring fresh concrete when the fibres can still move. The technique is most relevant for manufacturing prefabricated elements such as beams or columns. However, the parameters of such a field are not immediately apparent, as they depend on the specific fibre reaction to the magnetic field. In this study, a numerical model was created in ANSYS Maxwell to examine the mechanical torque acting on fibres placed in a magnetic field with varying parameters. The model consists of a single fibre placed between two Helmholtz coils. The simulations were verified with an experimental setup as well as theoretical relationships. Ten different fibre types, both straight and hook-ended, were examined. The developed model can be successfully used to study the behaviour of fibres in a magnetic field. The fibre size plays the most important role together with the magnetic saturation of the fibre material. Multiple fibres show significant interactions.

Department of Electrotechnology Faculty of Electrical Engineering Czech Technical University Prague Technická 2 166 27 Prague Czech Republic

Experimental Centre Faculty of Civil Engineering Czech Technical University Prague Thákurova 7 166 29 Prague Czech Republic

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Bentur A., Mindess S. Fibre Reinforced Cementitious Composites. CRC Press; Boca Raton, FL, USA: 2019. p. 624.

Serna P., Llano-Torre A., Martí-Vargas J.R., Navarro-Gregori J. Fibre Reinforced Concrete: Improvements and Innovations. 1st ed. Springer; Cham, Switzerland: 2021. p. 2021.

Yoo D.Y., Banthia N. Mechanical and structural behaviors of ultra-high-performance fiber-reinforced concrete subjected to impact and blast. Constr. Build. Mater. 2017;149:416–431. doi: 10.1016/j.conbuildmat.2017.05.136. DOI

Wei J., Li J., Wu C., Liu Z.-X., Li J. Hybrid fibre reinforced ultra-high performance concrete beams under static and impact loads. Eng. Struct. 2021;245:112921. doi: 10.1016/j.engstruct.2021.112921. DOI

Vivas J., Zerbino R., Torrijos M., Giaccio G. Effect of the fibre type on concrete impact resistance. Constr. Build. Mater. 2020;264:120200. doi: 10.1016/j.conbuildmat.2020.120200. DOI

Liu J., Li J., Fang J., Su Y., Wu C. Ultra-high performance concrete targets against high velocity projectile impact—A-state-of-the-art review. Int. J. Impact Eng. 2022;160:104080. doi: 10.1016/j.ijimpeng.2021.104080. DOI

Eik M., Puttonen J., Herrmann H. An orthotropic material model for steel fibre reinforced concrete based on the orientation distribution of fibres. Compos. Struct. 2015;121:324–336. doi: 10.1016/j.compstruct.2014.11.018. DOI

Zhou B., Uchida Y. Relationship between fiber orientation/distribution and post-cracking behaviour in ultra-high-performance fiber-reinforced concrete (UHPFRC) Cem. Concr. Compos. 2017;83:66–75. doi: 10.1016/j.cemconcomp.2017.07.007. DOI

Švec O., Žirgulis G., Bolander J.E., Stang H. Influence of formwork surface on the orientation of steel fibres within self-compacting concrete and on the mechanical properties of cast structural elements. Cem. Concr. Compos. 2014;50:60–72. doi: 10.1016/j.cemconcomp.2013.12.002. DOI

Ďubek M., Makýš P., Petro M., Ellingerová H., Antošová N. The Development of Controlled Orientation of Fibres in SFRC. Materials. 2021;14:4432. doi: 10.3390/ma14164432. PubMed DOI PMC

Kobaka J. A Statistical Model of Fibre Distribution in a Steel Fibre Reinforced Concrete. Materials. 2021;14:7297. doi: 10.3390/ma14237297. PubMed DOI PMC

Ding T., Xiao J., Zou S., Zhou X. Anisotropic behavior in bending of 3D printed concrete reinforced with fibers. Compos. Struct. 2020;254:112808. doi: 10.1016/j.compstruct.2020.112808. DOI

Sun J., Aslani F., Lu J., Wang L., Huang Y., Ma G. Fibre-reinforced lightweight engineered cementitious composites for 3D concrete printing. Ceram. Int. 2021;47:27107–27121. doi: 10.1016/j.ceramint.2021.06.124. DOI

Arunothayan A.R., Nematollahi B., Ranade R., Bong S.H., Sanjayan J.G., Khayat K.H. Fiber orientation effects on ultra-high performance concrete formed by 3D printing. Cem. Concr. Res. 2021;143:106384. doi: 10.1016/j.cemconres.2021.106384. DOI

Yang Y., Wu C., Liu Z., Wang H., Ren Q. Mechanical anisotropy of ultra-high performance fibre-reinforced concrete for 3D printing. Cem. Concr. Compos. 2022;125:104310. doi: 10.1016/j.cemconcomp.2021.104310. DOI

Raju R.A., Lim S., Akiyama M., Kageyama T. Effects of concrete flow on the distribution and orientation of fibers and flexural behavior of steel fiber-reinforced self-compacting concrete beams. Constr. Build. Mater. 2020;262:119963. doi: 10.1016/j.conbuildmat.2020.119963. DOI

Alberti M., Enfedaque A., Gálvez J. A review on the assessment and prediction of the orientation and distribution of fibres for concrete. Compos. Part B Eng. 2018;151:274–290. doi: 10.1016/j.compositesb.2018.05.040. DOI

Zhao Y., Bi J., Wang Z., Huo L., Guan J., Zhao Y., Sun Y. Numerical simulation of the casting process of steel fiber reinforced self-compacting concrete: Influence of material and casting parameters on fiber orientation and distribution. Constr. Build. Mater. 2021;312:125337. doi: 10.1016/j.conbuildmat.2021.125337. DOI

Miller A.I., Björklund F.R. Method of Reinforcing Concrete with Fibres. US4062913A. U.S. Patent. 1977 December 13;

Wijffels M., Wolfs R., Suiker A., Salet T. Magnetic orientation of steel fibres in self-compacting concrete beams: Effect on failure behaviour. Cem. Concr. Compos. 2017;80:342–355. doi: 10.1016/j.cemconcomp.2017.04.005. DOI

Villar V.P., Medina N.F. Alignment of hooked-end fibres in matrices with similar rheological behaviour to cementitious composites through homogeneous magnetic fields. Constr. Build. Mater. 2018;163:256–266. doi: 10.1016/j.conbuildmat.2017.12.084. DOI

Hajforoush M., Kheyroddin A., Rezaifar O. Investigation of engineering properties of steel fiber reinforced concrete exposed to homogeneous magnetic field. Constr. Build. Mater. 2020;252:119064. doi: 10.1016/j.conbuildmat.2020.119064. DOI

Xue W., Chen J., Xie F., Feng B. Orientation of Steel Fibers in Magnetically Driven Concrete and Mortar. Materials. 2018;11:170. doi: 10.3390/ma11010170. PubMed DOI PMC

Künzel K., Papež V., Carrera K., Konrád P., Mára M., Kheml P., Sovják R. Electromagnetic Properties of Steel Fibres for Use in Cementitious Composites, Fibre Detection and Non-Destructive Testing. Materials. 2021;14:2131. doi: 10.3390/ma14092131. PubMed DOI PMC

ANSYS Inc. ANSYS 2021 R1. 2021. 275 Technology Drive, Canonsburg, PA 15317, USA. [(accessed on 23 February 2021)]. Available online: https://www.ansys.com/

Jin J.M. The Finite Element Method in Electromagnetics. 3rd ed. Wiley-IEEE Press; Piscataway, NJ, USA: 2014. p. 876.

Ghani S.A., Ahmad Khiar M.S., Chairul I.S., Lada M.Y., Rahim N.H. Study of magnetic fields produced by transmission line tower using finite element method (FEM); Proceedings of the 2014 2nd International Conference on Technology, Informatics, Management, Engineering Environment; Bandung, Indonesia. 19–21 August 2014; pp. 64–68. DOI

Giorla D., Roccella R., Lo Frano R., Sannazzaro G. EM zooming procedure in ANSYS Maxwell 3D. Fusion Eng. Des. 2018;132:67–72. doi: 10.1016/j.fusengdes.2018.04.096. DOI

Bronaugh E.L. Helmholtz coils for calibration of probes and sensors: Limits of magnetic field accuracy and uniformity; Proceedings of the International Symposium on Electromagnetic Compatibility; Atlanta, GA, USA. 14–18 August 1995; pp. 72–76.

Parry J. Helmholtz Coils and Coil Design. In: Collinson D., Creer K., Runcorn S., editors. Methods in Palaeomagnetism. Volume 3. Elsevier; Amsterdam, The Netherlands: 2013. pp. 551–567. Developments in Solid Earth Geophysics. DOI

Romana L., Jindřich F., Soukupová L., Valentin J. Experimental Stresss Analysis. Czech Society for Mechanics; Prague, Czech Republic: 2016. Ultrasound gel as suitable tool for simulation of the fibre orientation in the fibre reinforced concrete; pp. 1–4.

Ida N. Engineering Electromagnetics. 4th ed. Springer; Cham, Switzerland: 2021. p. 1028. DOI