Browsing by Author "Aydin, U."
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- Determination of stress dependent magnetostriction from a macroscopic magneto-mechanical model and experimental magnetization curves
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä(2020) M'zali, N.; Martin, F.; Aydin, U.; Belahcen, A.; Benabou, A.; Henneron, T.In this paper, we propose a method to identify the magnetostrictive behavior of electrical steel sheet submitted to a mechanical loading. The technique relies on the use of a magneto-mechanical model including the magnetostrictive phenomenon, namely the anhysteretic Jiles-Atherton-Sablik (JAS) model, and experimental macroscopic stress dependent magnetization curves. The method is illustrated with measured magnetization curves of a non-oriented (NO) electrical steel sheet under different stresses. Furthermore, the influence of a bi-axial mechanical loading on the magnetostrictive behavior is analyzed with the help of an equivalent stress. - Effect of multi-axial stress on iron losses of electrical steel sheets
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä(2019-01-01) Aydin, U.; Rasilo, P.; Martin, F.; Belahcen, A.; Daniel, L.; Haavisto, A.; Arkkio, A.The effect of multi-axial stress on the iron losses of a non-oriented electrical steel sheet under alternating magnetization is analyzed. Multi-axial magneto-mechanical measurements on a M400-50A grade non-oriented electrical steel sheet are performed by using a custom made single sheet tester device. The measured losses are separated into hysteresis, classical and excess loss components by using statistical loss theory, and the effect of various stress configurations on the hysteresis and the excess loss components is analyzed. By utilizing the statistical loss theory, an equivalent stress model and a magneto-elastic invariant based model are derived. These models can be used to predict the iron loss evolution under multi-axial stress even if only uniaxial stress dependent measurements are available. The accuracy of both models to predict the multi-axial stress dependent iron losses is found to be satisfactory when they are identified only from uniaxial stress dependent measurements. The invariant based model is shown to be slightly more accurate for the studied material. - Modeling a Fe-Ga energy harvester fitted with magnetic closure using 3D magneto-mechanical finite element model
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä(2020-04-15) Ahmed, U.; Aydin, U.; Zucca, M.; Palumbo, S.; Kouhia, R.; Rasilo, P.This paper presents the implementation of magneto-mechanical constitutive law utilizing thermodynamic approach in a 3D finite element solver using COMSOL Multiphysics software. The analytical expression for the magnetic field strength and stress is derived from the constitutive model utilizing magnetic flux density and mechanical strain as state variables. The constitutive model is successfully implemented in commercially available software COMSOL. This implementation allows 3D analysis of an energy harvester device efficiently and accurately. A prototype concept device is developed to validate the model and its implementation. The device is tested under uniaxial compressive loading by varying the preload, dynamic load and magnetic bias. The model is validated by comparing the simulated and experimental results. The comparison shows that the model can reasonably predict the optimal value of the preload and magnetic bias yielding maximum power and is able to follow the measurement trends. This model can be used as a suitable tool to analyze the behavior of the concept energy harvesters and determine the optimal design parameters. - Modeling of multi-axial stress dependent iron losses in electrical steel sheets
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä(2020-06-15) Aydin, U.; Rasilo, P.; Martin, F.; Belahcen, A.; Daniel, L.; Arkkio, A.Modeling the effect of multi-axial mechanical stress on the iron losses of an M400-50A grade non-oriented electrical steel sheet is studied. By utilizing the statistical loss theory, the total measured iron losses are first segregated to hysteresis, classical eddy current and excess losses. Then, the stress dependency of the excess losses is modeled by correlating them to the hysteresis losses under multi-axial stress. This correlation, coupled with a magneto-elastic invariant based loss model, can be used to predict the iron loss evolution with reasonable accuracy under multi-axial stress when only iron loss data under no applied stress at various excitation frequencies and under only two uniaxial stress levels at quasi-static excitation are available. Consequently, this approach significantly reduces the required measurement data for estimating the iron losses under multi-axial stress. - Modeling the Effect of Multiaxial Stress on Magnetic Hysteresis of Electrical Steel Sheets: A Comparison
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä(2017) Aydin, U.; Rasilo, P.; Martin, F.; Singh, D.; Daniel, L.; Belahcen, A.; Kouhia, R.; Arkkio, A.The abilities of a simplified multiscale and a Helmholtz energy HE models models from the literature to predict the multiaxial stress dependent magnetic hysteresis behavior of electrical steel sheets are analyzed. The identification of the models is performed using only uniaxial magneto-mechanical measurements. Reasonable accuracy between the measurements and the modeled results is obtained. With this paper, the applicability of the HE-based model for predicting the multiaxial magneto-mechanical behavior of electrical steel sheets is verified for the first time. The differences between the studied models and possible modifications to increase the accuracy of them are discussed. Some brief guidelines for the applications are given. - Rotational Single Sheet Tester for Multiaxial Magneto-Mechanical Effects in Steel Sheets
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä(2019-03-01) Aydin, U.; Martin, F.; Rasilo, P.; Belahcen, A.; Haavisto, A.; Singh, D.; Daniel, L.; Arkkio, A.A detailed design of a new rotational single sheet tester device which allows comprehensive multiaxial magneto-mechanical analysis of ferromagnetic sheets is proposed. The challenges that arose during the mechanical and magnetic design phases are addressed. The applicability of the device is tested by performing magneto-mechanical measurements on an M400-50A electrical steel sheet. Results under several multiaxial magneto-mechanical loadings with circular and alternating magnetic flux densities are reported. It is shown that the effect of multiaxial stress on iron losses can be much more significant than that of uniaxial stress.