Detail publikace

A Magnetic Method for Testing of Homogeneity of Fibre Concrete

HOBST, L. ANTON, O. VALA, J. HORÁK, M.

Originální název

A Magnetic Method for Testing of Homogeneity of Fibre Concrete

Typ

článek ve sborníku ve WoS nebo Scopus

Jazyk

angličtina

Originální abstrakt

Homogeneity of fibre concrete structures, characterized, from the macroscopic point of view, by (nearly) constant volume fraction of randomly oriented fibre particles, determines their mechanical, thermal, etc. properties, consequently their long-time behaviour, reliability and range of user applications. Destructive validation of homogeneity is available under laboratory conditions, but frequently impossible in situ. A reasonable alternative to the radiographic control method can be based on stationary measurements of magnetic field strength, thanks to the composite structure with ferromagnetic particles, incorporated in the concrete matrix. The permanent magnet generates a (nearly) stationary magnetic field, whose distribution is described by the Laplace equation, supplied by appropriate boundary conditions, containing the effective relative magnetic permeability as just one material parameter; the crucial problem is then to estimate some formally homogenized (with a priori unknown permeability of fibres) as a function of , without the a priori knowledge of permeability of particles. The paper demonstrates that in such case the numerical analysis of solution of the Laplace equation can be avoided, thus is allowed to be evaluated directly, using local measurements of the magnetic field strength from the Hall-effect-based measurement and non-trivial MATLAB-supported computations, based on the least squares optimization, supported by the Newton method for the numerical evaluation of roots of nonlinear equations.

Klíčová slova

Fibre concrete, non-destructive testing, Laplace equation for magnetic fields, homogenization techniques, least square method, MATLAB-supported computations.

Autoři

HOBST, L.; ANTON, O.; VALA, J.; HORÁK, M.

Rok RIV

2011

Vydáno

7. 12. 2011

Místo

Brno

ISBN

978-80-7204-774-1

Kniha

9th International Conference NDT 2011 Nedestruktivní testování v technických oborech

Strany od

19

Strany do

29

Strany počet

10

BibTex

@inproceedings{BUT76539,
  author="Leonard {Hobst} and Ondřej {Anton} and Jiří {Vala} and Michal {Horák}",
  title="A Magnetic Method for Testing of Homogeneity of Fibre Concrete",
  booktitle="9th International Conference NDT 2011 Nedestruktivní testování v technických oborech",
  year="2011",
  pages="19--29",
  address="Brno",
  isbn="978-80-7204-774-1"
}