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Article
Publication date: 8 May 2009

Krzysztof Chwastek, Jan Szczygłowski and Wiesław Wilczyński

The aim of the paper is to present a simple approach to modelling minor hysteresis loops in grain‐oriented steel sheets under quasi‐static and dynamic conditions. The hysteresis…

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Abstract

Purpose

The aim of the paper is to present a simple approach to modelling minor hysteresis loops in grain‐oriented steel sheets under quasi‐static and dynamic conditions. The hysteresis phenomenon is described with a recently developed hybrid model, which combines ideas inherent in the product Preisach model and the Jiles‐Atherton description. The dynamic effects due to eddy currents are taken into account in the description using a lagged response with respect to the input.

Design/methodology/approach

It is assumed that some model parameters might be dependent on the level of relative magnetization within the material. Their dependencies could be given as power laws. The values of scaling coefficients in power laws are determined.

Findings

A satisfactory agreement of experimental and modelled quasi‐static and dynamic hysteresis loops is obtained.

Research limitations/implications

The present study provides a starting point for further verification of the approach for other classes of soft magnetic materials, which could be described with the developed model. At present, the approach to model minor loops by the update of model parameters is verified for the B‐sine excitation case.

Practical implications

The “branch‐and‐bound” optimization algorithm is a useful tool for recovery of the values of both model parameters and scaling coefficients as well.

Originality/value

The recently developed hybrid description of hysteresis phenomenon can be successfully extended to take into account symmetric minor loops. The developed approach could be a framework to develop a comprehensive description of magnetization phenomena in the future.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 28 no. 3
Type: Research Article
ISSN: 0332-1649

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Article
Publication date: 24 June 2019

Mariusz Najgebauer, Jan Szczyglowski, Barbara Slusarek and Marek Przybylski

The purpose of this paper is to examine scaling algorithms in the description and modelling of power loss in soft magnetic composites (SMCs).

146

Abstract

Purpose

The purpose of this paper is to examine scaling algorithms in the description and modelling of power loss in soft magnetic composites (SMCs).

Design/methodology/approach

Three scaling algorithms are examined to determine the most appropriate description of power loss in magnetic composites. The scaling coefficients are estimated in such a way that all measurement data should be collapsed onto a single curve, given in the scaled coordinates. The coefficient estimation is based on a non-linear optimization using the generalized reduced gradient method. The obtained formulae are then used in the power loss modelling.

Findings

It is revealed that only two-component formulae are suitable for the scaling analysis of power loss because these allow obtaining of the collapse of measurement data.

Research limitations/implications

This study considers just one type of SMC (Somaloy 700). Further research will be devoted to the verification of the scaling approach to the power loss modelling for other types of magnetic composites.

Practical implications

The power loss is a basic property of soft magnetic materials, which determines their practical applications. The scaling approach to the power loss modelling gives quite simple models that require a reduced number of measurement data to estimate coefficients.

Originality/value

The scaling algorithms can be a useful tool in the analysis and designing of magnetic circuits made of SMCs.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 38 no. 4
Type: Research Article
ISSN: 0332-1649

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Article
Publication date: 5 May 2015

Barbara Ślusarek, Jan Szczyglowski, Krzysztof Chwastek and Bartosz Jankowski

– The purpose of this paper is to examine the relationships between processing conditions and magnetic properties of cores made of Soft Magnetic Composite (SMC) Somaloy 500.

235

Abstract

Purpose

The purpose of this paper is to examine the relationships between processing conditions and magnetic properties of cores made of Soft Magnetic Composite (SMC) Somaloy 500.

Design/methodology/approach

The effects of compaction pressure and hardening temperature may be combined considering SMC density. This quantity may be chosen for optimization of properties of ready-made cores. In order to describe hysteresis loops the phenomenological model based on hyperbolic tangent transformation is applied.

Findings

SMC density affects substantially the shape of hysteresis loop. The paper provides a number of charts useful for checking how the parameters of the hysteresis model are affected.

Research limitations/implications

The present study considers just one composition of the SMC and one type of lubricant. Future research shall be devoted to verification of the approach on a wider class of SMCs.

Practical implications

Material density may be a relevant quantity in optimization of magnetic properties of ready-made SMC cores. The simple hysteresis model based on the, “effective field” concept and Takács’ idea of hyperbolic tangent transformation may be useful for description of hysteresis curves of SMC cores. Model parameters are sensitive against variations of material density.

Originality/value

The results of the analysis may be useful for designers of magnetic circuits made of SMCs.

Details

COMPEL: The International Journal for Computation and Mathematics in Electrical and Electronic Engineering, vol. 34 no. 3
Type: Research Article
ISSN: 0332-1649

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Article
Publication date: 27 January 2022

Khalizani Khalid, Khalisanni Khalid and Ross Davidson

The purpose of this paper is to identify the factor structure of safety culture construct among engineering students at university context and to examine the measurement…

174

Abstract

Purpose

The purpose of this paper is to identify the factor structure of safety culture construct among engineering students at university context and to examine the measurement invariance of this instrument across different socio-demographic groups in a sample of engineering students in the United Arab Emirates (UAE).

Design/methodology/approach

An exploratory online questionnaire was completed by 770 undergraduate and postgraduate engineering students across the UAE. Data were analyzed using a diversified multi-group and a robust and sophisticated cross-validation testing strategy. Confirmatory factor analysis (CFA) was used to test factor structures identified in previous studies. Multi-group invariance testing was conducted to determine the extent to which factor structure is comparable across groups (i.e. gender, educational and experiential background).

Findings

Three-factor model was preferred for its parsimony. The results showed that the level of safety awareness and attitude is relatively satisfactory, whereas safety behaviour is inadequate. No significant difference was showed in multi-group invariance between demographic groups.

Research limitations/implications

This research is a cross-sectional study and limited to the views of engineering students (informal group). The study would benefit from both informal and formal groups in assessing safety culture at university for a robust empirical evidence. The research highlights relevant implications for policy and program development, by pointing to the need to promote safety culture and mitigate safety-related accidents among engineering students.

Originality/value

This paper offers insight into benefit of understanding the level of safety culture among engineering students and extend knowledge of informal group involvement in safety-related accidents at university level.

Details

Journal of Engineering, Design and Technology , vol. 22 no. 2
Type: Research Article
ISSN: 1726-0531

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