On measurement and modelling of 2D magnetization and magnetostriction of SiFe sheets

by Lundgren, Anders

The development and technological aspects of a 2D magnetization and magnetostriction measurement setup are documented and described. Local magnetic intensity and ux density are measured with Rogowski and material encircling coils. In-plane strain is measured with a homodyne laser interferometer. Measured and processed time-domain signals, hysteresis plots and signature data such as loss are presented by an e cient and communicative interface. Measurements on quadratic silicon iron sheet samples are included. Material types tested on the setup are with non-oriented and oriented textures. Possible excitations include uniaxial alternating magnetic eld in the rolling and transverse directions between 10 and 300 Hz at least. Rotational excitations are possible at least for the non-oriented and conventional grain-oriented types. The value of the setup lies in the possibility of using it for routine measurements on samples. The interplay between mathematical modelling and physical experimenting is described. Investigations by algebraic and numerical methods are done to nd a possible way to parameterize material behaviour and include this behaviour in nite element programs. On the basis of a proposed one-dimensional nonlinear model, algorithms are devised to compute magnetostrictive responses to uniaxially alternating magnetic elds. An experimental FEM program to calculate strain elds from inhomogeneous magnetization is developed. Its use for investigation of sample behaviour during the operation of the setup is shown. The value of the proposed modelling methodology lies in the study of possibilities of lowering the production of magnetostrictive vibration in transformer, motor and generator cores. IEEE index terms: Magnetostriction, silicon steel, magnetic cores, strain, interferometry, magnetic anisotropy, magnetic elds, magnetic measurements, magnetoelasticity, nonlinear magnetics, power transformers, power distribution acoustic noise, nite element methods. TRITA-EEA-9901 ISSN 1100-1593