Search results
1 – 10 of 25Brahim Ladghem-Chikouche, Lazhar Roubache, Kamel Boughrara, Frédéric Dubas, Zakarya Djelloul-Khedda and Rachid Ibtiouen
The purpose of this study is to present a novel extended hybrid analytical method (HAM) that leverages a two-dimensional (2-D) coupling between the semi-analytical Maxwell–Fourier…
Abstract
Purpose
The purpose of this study is to present a novel extended hybrid analytical method (HAM) that leverages a two-dimensional (2-D) coupling between the semi-analytical Maxwell–Fourier analysis and the finite element method (FEM) in Cartesian coordinates.
Design/methodology/approach
The proposed model is applied to flat permanent-magnet linear electrical machines with rotor-dual. The magnetic field solution across the entire machine is established by coupling an exact analytical model (AM), designed for regions with relative magnetic permeability equal to unity, with a FEM in ferromagnetic regions. The coupling between AM and FEM occurs bidirectionally (x, y) along the edges separating teeth regions and their adjacent regions through applied boundary conditions.
Findings
The developed HAM yields accurate results concerning the magnetic flux density distribution, cogging force and induced voltage under various operating conditions, including magnetic or geometric parameters. A comparison with hybrid finite-difference and hybrid reluctance network methods demonstrates very satisfactory agreement with 2-D FEM.
Originality/value
The original contribution of this paper lies in establishing a direct coupling between the semi-analytical Maxwell–Fourier analysis and the FEM, particularly at the interface between adjacent regions with differing magnetic parameters.
Details
Keywords
Renato Zona, Luca Esposito, Simone Palladino and Vincenzo Minutolo
Heterogeneous and micro-structured materials have been the object of multiscale and homogenization techniques aimed at recognizing the elastic properties of the equivalent…
Abstract
Purpose
Heterogeneous and micro-structured materials have been the object of multiscale and homogenization techniques aimed at recognizing the elastic properties of the equivalent continuum. The proposed investigation deals with the mechanical characterization of the heterogeneous material structured metamaterials through analyzing the ultimate strength using the limit analysis of the Representative Volume Element (RVE). To get the desired material strength, a novel finite element formulation based on the derivation of self-equilibrated solutions through the finite elements devoted to calculating the lower bound theorem has been implemented together with the limit analysis in Melàn’s formulation.
Design/methodology/approach
The finite element formulation is based on discrete mapping of Volterra dislocations in the structure using isoparametric representation. Using standard finite element techniques, the linear operator V, which relates the self-equilibrated internal solicitation to displacement-like nodal parameters, has been built through finite element discretization of displacement and strain.
Findings
The proposed work presented an elastic homogenization of the mechanical properties of an elementary cell with a geometry known in the literature, the isotropic truss. The matrix of elastic constants was calculated by subjecting the RVE to numerical load tests, simulated with a commercial FEM calculation code. This step showed the dependence of the isotropy properties, verified with Zener theory, on the density of the RVE. The isotropy condition of the material is only achieved for certain section ratios between body-centered cubic (BCC) and face-centered cubic (FCC), neglecting flexural effects at the nodes. The density that satisfies Zener’s conditions represents the isotropic geomatics of the isotropic truss.
Originality/value
For the isotropic case, the VFEM procedure was used to evaluate the isotropy of the limit domain and was compared with the Mises–Schleicher limit domain. The evaluation of residual ductility and dissipation energy allowed a measurement parameter for the limit anisotropy to be defined. The novelty of the proposal consisted in the formulation of both the linearized and the nonlinear limit locus of the material; hence, it furnished the starting point for further limit analysis of the structures whose elementary volume has been described through the proposed approach.
Details
Keywords
Jie Wu, Kang Wang, Ming Zhang, Leilei Guo, Yongpeng Shen, Mingjie Wang, Jitao Zhang and Vaclav Snasel
When solving the cogging torque of complex electromagnetic structures, such as consequent pole hybrid excitation synchronous (CPHES) machine, traditional methods have a huge…
Abstract
Purpose
When solving the cogging torque of complex electromagnetic structures, such as consequent pole hybrid excitation synchronous (CPHES) machine, traditional methods have a huge computational complexity. The notable feature of CPHES machine is the symmetric range of field-strengthening and field-weakening, but this type of machine is destined to be equipped with a complex electromagnetic structure. The purpose of this paper is to propose a hybrid analysis method to quickly and accurately solve the cogging torque of complex 3D electromagnetic structure, which is applicable to CPHES machine with different magnetic pole shapings.
Design/methodology/approach
In this paper, a hybrid method for calculating the cogging torque of CPHES machine is proposed, which considers three commonly used pole shapings. Firstly, through magnetic field analysis, the complex 3D finite element analysis (FEA) is simplified to 2D field computing. Secondly, the discretization method is used to obtain the distribution of permeance and permeance differential along the circumference of the air-gap, taking into account the effect of slots. Finally, the cogging torque of the whole motor is obtained by using the idea of modular calculation and the symmetry of the rotor structure.
Findings
This method is applicable to different pole shapings. The experimental results show that the proposed method is consistent with 3D FEA and experimental measured results, and the average calculation time is reduced from 8 h to 4 min.
Originality/value
This paper proposes a new concept for calculating cogging torque, which is a hybrid calculation of dimension reduction and discretization modules. Based on magnetic field analysis, the 3D problem is simplified into a 2D issue, reducing computational complexity. Based on the symmetry of the machine structure, a modeling method for discretized analytical models is proposed to calculate the cogging torque of the machine.
Details
Keywords
Yi Xie and Baojin Zheng
This paper aims to apply the novel numerical model to analyze the effect of pillar material on the response of compound quartz crystal resonator (QCR) with an array of pillars…
Abstract
Purpose
This paper aims to apply the novel numerical model to analyze the effect of pillar material on the response of compound quartz crystal resonator (QCR) with an array of pillars. The performance of the proposed device compared to conventional QCR method was also investigated.
Design/methodology/approach
A finite element method model was developed to analyze the behavior of QCR coupled with an array of pillars. The model was composed of an elastic pillar, a solution and a perfectly matched layer. The validation of the model was performed through a comparison between its predictions and previous experimental measurements. Notably, a good agreement was observed between the predicted results and the experimental data.
Findings
The effect of pillar Young’s modulus on the coupled QCR and pillars with a diameter of 20 µm, a center-to-center spacing of 40 µm and a density of 2,500 kg/m3 was investigated. The results indicate that multiple vibration modes can be obtained based on Young’s modulus. Notably, in the case of the QCR–pillar in air, the second vibration mode occurred at a critical Young’s modulus of 0.2 MPa, whereas the first mode was observed at 3.75 Mpa. The vibration phase analysis revealed phase-veering behavior at the critical Young’s modulus, which resulted in a sudden jump-and-drop frequency shift. In addition, the results show that the critical Young’s modulus is dependent on the surrounding environment of the pillar. For instance, the critical Young’s modulus for the first mode of the pillar is approximately 3.75 Mpa in air, whereas it increases to 6.5 Mpa in water.
Originality/value
It was concluded that the performance of coupled QCR–pillar devices significantly depends on the pillar material. Therefore, choosing pillar material at critical Young’s modulus can lead to the maximum frequency shift of coupled QCR–pillar devices. The model developed in this work helps the researchers design pillars to achieve maximum frequency shift in their measurements using coupled QCR–pillar.
Details
Keywords
Vida Siahtiri, Welf Hermann Weiger, Christian Tetteh-Afi and Tobias Kraemer
As consumer debt can substantially impair subjective well-being, it is crucial for research to gain insights into how consumers can be motivated to improve financial planning…
Abstract
Purpose
As consumer debt can substantially impair subjective well-being, it is crucial for research to gain insights into how consumers can be motivated to improve financial planning. This paper aims to investigate how frontline employees in financial services can help consumers regulate their financial planning behaviors and how financial service providers can effectively support their frontline employees in this effort through leadership and organizational climate.
Design/methodology/approach
We incorporate regulatory focus theory and conservation of resource theory to develop a conceptual model that we test in a triadic study with a unique dataset collected from consumers, frontline employees, and managers in the banking sector.
Findings
We find that frontline employees must pay attention to the details of consumers’ needs and customize the service to those needs to trigger consumer promotion focus and stimulate consumers’ financial planning behaviors. Moreover, our results emphasize that the organization must act as an integrated entity. Thus, a manager’s servant leadership and an organizational climate of customer stewardship are crucial for frontline employees to transform consumers’ financial planning behaviors.
Research limitations/implications
The study highlights frontline employees’ key role in motivating consumer financial planning behavior, offering a new perspective in transformative service research on enhancing financial well-being.
Practical implications
The findings provide financial service providers with actionable implications for enhancing consumers’ financial planning. This benefits both consumers and financial institutions, as customers with greater spending power can buy more financial products.
Originality/value
This study advances transformative service research on consumer financial planning behavior, which has largely focused on consumer-related or society-level variables, by exploring the role of frontline employees and organizational support in terms of leadership and climate.
Details
Keywords
Long Chen, Zheyu Zhang, Ni An, Xin Wen and Tong Ben
The purpose of this study is to model the global dynamic hysteresis properties with an improved Jiles–Atherton (J-A) model through a unified set of parameters.
Abstract
Purpose
The purpose of this study is to model the global dynamic hysteresis properties with an improved Jiles–Atherton (J-A) model through a unified set of parameters.
Design/methodology/approach
First, the waveform scaling parameters β, λk and λc are used to improve the calculation accuracy of hysteresis loops at low magnetic flux density. Second, the Riemann–Liouville (R-L) type fractional derivatives technique is applied to modified static inverse J-A model to compute the dynamic magnetic field considering the skin effect in wideband frequency magnetization conditions.
Findings
The proposed model is identified and verified by modeling the hysteresis loops whose maximum magnetic flux densities vary from 0.3 to 1.4 T up to 800 Hz using B30P105 electrical steel. Compared with the conventional J-A model, the global simulation ability of the proposed dynamic model is much improved.
Originality/value
Accurate modeling of the hysteresis properties of electrical steels is essential for analyzing the loss behavior of electrical equipment in finite element analysis (FEA). Nevertheless, the existing inverse Jiles–Atherton (J-A) model can only guarantee the simulation accuracy with higher magnetic flux densities, which cannot guarantee the analysis requirements of considering both low magnetic flux density and high magnetic flux density in FEA. This paper modifies the dynamic J-A model by introducing waveform scaling parameters and the R-L fractional derivative to improve the hysteresis loops’ simulation accuracy from low to high magnetic flux densities with the same set of parameters in a wide frequency range.
Details
Keywords
Xiaobao Chai, Jinglin Liu, RuiZhi Guan and Minglang Xiao
To improve the output torque density of the machine and to be better suited for automation applications, this paper aims to propose a double-permanent-magnet enhanced hybrid…
Abstract
Purpose
To improve the output torque density of the machine and to be better suited for automation applications, this paper aims to propose a double-permanent-magnet enhanced hybrid stepping machine (DPMEHSM) with tangential and radial magnetization.
Design/methodology/approach
First, the structure of DPMEHSM is introduced and its operation principle is analyzed by describing the variation in stator poles versus time. Second, based on the similar electrical load and amount of PM, the size equations of the DPMEHSM are designed and the main parameters are presented. Third, the electromagnetic performances including the PM flux linkage distribution, magnetic density distribution, air-gap field, back electromotive force (back-EMF), detent torque, holding torque and output torque of DPMEHSM and stator-PM hybrid stepping machine (SPMHSM) are analyzed based on the finite element method.
Findings
The results show that the DPMEHSM has superiority in back-EMF, holding torque and output torque.
Originality/value
This paper proposes a DPMEHSM with tangential and radial magnetization to improve the output torque density.
Details
Keywords
Sylvia Novillo-Villegas, Wendy Anzules-Falcones and Juan Ignacio Martin-Castilla
This study aims to explore the relationship between the innovation capacity and performance of manufacturing firms in the Ecuadorian pharmaceutical and chemical sectors using…
Abstract
Purpose
This study aims to explore the relationship between the innovation capacity and performance of manufacturing firms in the Ecuadorian pharmaceutical and chemical sectors using strategic foresight analysis.
Design/methodology/approach
From an extensive literature review, the fundamental variables related to manufacturing firms’ innovation for better performance were identified. Six hypotheses and actions were proposed related to financing, economic resources, capacities and research and development. Several scenarios were tested through foresight methodology to determine the more appropriate to be implemented by manufacturing firms over the next five years.
Findings
Scenario 01, where all the hypotheses resulted positive, has a 15.3% probability of occurrence. The results offer a relevant understanding of the behavior of the variables proposed as strategic actions for the sector.
Originality/value
To the best of the authors’ knowledge, foresight methodology is applied for the first time to analyze the manufacturing sector in Ecuador. The authors propose a plan of action from the strategic scenario identified in this study, supporting the development of the industrial sectors under study.
Details
Keywords
Huijie Jin, Suihan Sui and Changyin Gao
Torque is one of the main parameters reflecting the operation status and detection of a mechanical rotation system. The use of quartz pillar to design torque sensors has advantage…
Abstract
Purpose
Torque is one of the main parameters reflecting the operation status and detection of a mechanical rotation system. The use of quartz pillar to design torque sensors has advantage over the use of quartz disk, but research into the torsional effect of quartz pillar is rare. This paper aims to investigate a novel type of torque sensor based on piezoelectric torsional effect.
Design/methodology/approach
Based on the theory of anisotropic elasticity and the Maxwell electromagnetism, the torsion stress and distribution of surface charge of a rectangular quartz pillar are calculated. Using finite element analysis, the polarized electric field of the piezoelectric pillar is solved. According to the theoretical calculation of torsional effect of piezoelectric quartz pillar, detection electrodes are mounted on the surface of the quartz pillar and a new type of torque sensor is designed.
Findings
The calibration experimental results show that the bound charges are proportional to the torque applied, and the torque sensor has fully reached the dynamometer standard.
Originality/value
This paper shows that the torsional effect of the developed piezoelectric quartz pillar can be used to create a new type of piezoelectric torque sensor.
Details
Keywords
Volkan Karaca and Mehmet Bağış
This study aims to investigate the relationships between managers’ cognitive styles, dynamic managerial capabilities and firms’ perceived international performance. The study is…
Abstract
Purpose
This study aims to investigate the relationships between managers’ cognitive styles, dynamic managerial capabilities and firms’ perceived international performance. The study is based on cognitive-experiential self-theory, dynamic managerial capabilities and international entrepreneurship.
Design/methodology/approach
Data were collected from 283 managers of small medium enterprises (SMEs) in Türkiye, an emerging economy. The research was conducted using quantitative methods, and Smart partial least squares (PLS) 4 software was used for data analysis. The data were examined through structural equation modelling and mediation analyses.
Findings
Findings indicate that rational cognitive styles positively influence managerial human capital, managerial social capital, managerial cognition and perceived international performance. However, the effect of intuitive cognitive styles was confirmed only on managerial cognition. Additionally, it was found that managerial cognition positively affects perceived international performance, whereas managerial social capital has a negative impact. However, the effects of managerial human capital could not be confirmed. Moreover, a full mediation relationship of managerial cognition between intuitive cognitive styles and perceived international performance was identified.
Originality/value
This research carves out a unique niche by synergizing cognitive-experiential self-theory with dynamic managerial capabilities to investigate their conjoined effect on firms’ international performance, an area previously underexplored. Unveiling insights from burgeoning economies like Türkiye enriches the existing body of knowledge, offering substantial contributions to the field of international business.
Details