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1 – 10 of over 36000Jan Karthaus, Silas Elfgen and Kay Hameyer
Magnetic properties of electrical steel are affected by mechanical stress. In electrical machines, influences because of manufacturing and assembling and because of operation…
Abstract
Purpose
Magnetic properties of electrical steel are affected by mechanical stress. In electrical machines, influences because of manufacturing and assembling and because of operation cause a mechanical stress distribution inside the steel lamination. The purpose of this study is to analyse the local mechanical stress distribution and its consequences for the magnetic properties which must be considered when designing electrical machines.
Design/methodology/approach
In this paper, an approach for modelling stress-dependent magnetic material properties such as magnetic flux density using a continuous local material model is presented.
Findings
The presented model shows a good approximation to measurement results for mechanical tensile stress up to 100 MPa for the studied material.
Originality/value
The presented model allows a simple determination of model parameters by using stress-dependent magnetic material measurements. The model can also be used to determine a scalar mechanical stress distribution by using a known magnetic flux density distribution.
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Examines the tenth published year of the ITCRR. Runs the whole gamut of textile innovation, research and testing, some of which investigates hitherto untouched aspects. Subjects…
Abstract
Examines the tenth published year of the ITCRR. Runs the whole gamut of textile innovation, research and testing, some of which investigates hitherto untouched aspects. Subjects discussed include cotton fabric processing, asbestos substitutes, textile adjuncts to cardiovascular surgery, wet textile processes, hand evaluation, nanotechnology, thermoplastic composites, robotic ironing, protective clothing (agricultural and industrial), ecological aspects of fibre properties – to name but a few! There would appear to be no limit to the future potential for textile applications.
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The purpose of this paper is to present an upscale theory of the thermal-mechanical coupling particle simulation for non-isothermal problems in two-dimensional quasi-static…
Abstract
Purpose
The purpose of this paper is to present an upscale theory of the thermal-mechanical coupling particle simulation for non-isothermal problems in two-dimensional quasi-static system, under which a small length-scale particle model can exactly reproduce the same mechanical and thermal results with that of a large length-scale one.
Design/methodology/approach
The objective is achieved by extending the upscale theory of particle simulation for two-dimensional quasi-static problems from an isothermal system to a non-isothermal one.
Findings
Five similarity criteria, namely geometric, material (mechanical and thermal) properties, gravity acceleration, (mechanical and thermal) time steps, thermal initial and boundary conditions (Dirichlet/Neumann boundary conditions), under which a small-length-scale particle model can exactly reproduce both the mechanical and thermal behavior with that of a large length-scale model for non-isothermal problems in a two-dimensional quasi-static system are proposed. Furthermore, to test the proposed upscale theory, two typical examples subjected to different thermal boundary conditions are simulated using two particle models of different length scale.
Originality/value
The paper provides some important theoretical guidances to modeling thermal-mechanical coupled problems at both the engineering length scale (i.e. the meter scale) and the geological length scale (i.e. the kilometer scale) using the particle simulation method directly. The related simulation results from two typical examples of significantly different length scales (i.e. a meter scale and a kilometer scale) have demonstrated the usefulness and correctness of the proposed upscale theory for simulating non-isothermal problems in two-dimensional quasi-static system.
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I. Ammar, L. Gerbaud, Ph. R. Marin and F. Wurtz
This paper deals with the collaborative design of electromagnetic devices over the internet network. The design is made by both mechanical and electrical engineers. So, the paper…
Abstract
Purpose
This paper deals with the collaborative design of electromagnetic devices over the internet network. The design is made by both mechanical and electrical engineers. So, the paper tries to show the importance but also constraints to size such a system using a collaborative optimisation process.
Design/methodology/approach
The paper compares two approaches in order to size an electromechanical actuator between mechanical and electrical engineers. In the first one, each profession designs its part, and only common constrained are negotiated. This can result in a design process with many iterations. In the second one, electrical and mechanical engineers built together a common model of the structure and a common list of specifications: this allows a global optimisation that is more efficient.
Findings
The main result of the paper is that the second approach in which a global model is built between electrical and mechanical engineers is more efficient.
Originality/value
The originality of the paper is to explore the problems and difficulties of an optimisation of an electromechanical device between engineers of different culture working together over the internet network.
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Discusses the 6th ITCRR, its breadth of textile and clothing research activity, plus the encouragement given to workers in this field and its related areas. States that, within…
Abstract
Discusses the 6th ITCRR, its breadth of textile and clothing research activity, plus the encouragement given to workers in this field and its related areas. States that, within the newer research areas under the microscope of the community involved, technical textiles focuses on new, ‘smart’ garments and the initiatives in this field in both the UK and the international community at large. Covers this subject at length.
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Duc Hai Nguyen, Hu Wang, Fan Ye and Wei Hu
The purpose of this paper is to investigate the mechanical properties’ behaviors of woven composite cut-out structures with specific parameters. Because of the complexity of…
Abstract
Purpose
The purpose of this paper is to investigate the mechanical properties’ behaviors of woven composite cut-out structures with specific parameters. Because of the complexity of micro-scale and meso-scale structure, it is difficult to accurately predict the mechanical material behavior of woven composites. Numerical simulations are increasingly necessary for the design and optimization of test procedures for composite structures made by the woven composite. The results of the proposed method are well satisfied with the results obtained from the experiment and other studies. Moreover, parametric studies on different plates based on the stacking sequences are investigated.
Design/methodology/approach
A multi-scale modeling approach is suggested. Back-propagation neural networks (BPNN), radial basis function (RBF) and least square support vector regression are integrated with efficient global optimization (EGO) to reduce the weight of assigned structure. Optimization results are verified by finite element analysis.
Findings
Compared with other similar studies, the advantage of the suggested strategy uses homogenized properties behaviors with more complex analysis of woven composite structures. According to investigation results, it can be found that 450/−450 ply-orientation is the best buckling load value for all the cut-out shape requirements. According to the optimal results, the BPNN-EGO is the best candidate for the EGO to optimize the woven composite structures.
Originality/value
A multi-scale approach is used to investigate the mechanical properties of a complex woven composite material architecture. Buckling of different cut-out shapes with the same area is surveyed. According to investigation, 45°/−45° ply-orientation is the best for all cut-out shapes. Different surrogate models are integrated in EGO for optimization. The BPNN surrogate model is the best choice for EGO to optimization difficult problems of woven composite materials.
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Jan Karthaus, Benedikt Groschup, Robin Krüger and Kay Hameyer
Due to the increasing amount of high power density high-speed electrical machines, a detailed understanding of the consequences for the machine’s operational behaviour and…
Abstract
Purpose
Due to the increasing amount of high power density high-speed electrical machines, a detailed understanding of the consequences for the machine’s operational behaviour and efficiency is necessary. Magnetic materials are prone to mechanical stress. Therefore, this paper aims to study the relation between the local mechanical stress distribution and magnetic properties such as magnetic flux density and iron losses.
Design/methodology/approach
In this paper, different approaches for equivalent mechanical stress criteria are analysed with focus on their applicability in electrical machines. Resulting machine characteristics such as magnetic flux density distribution or iron are compared.
Findings
The study shows a strong influence on the magnetic flux density distribution when considering the magneto-elastic effect for all analysed models. The influence on the iron loss is smaller due to a high amount of stress-independent eddy current loss component.
Originality/value
The understanding of the influence of mechanical stress on dimensions of electrical machines is important to obtain an accurate machine design. In this paper, the discussion on different equivalent stress approaches allows a new perspective for considering the magneto-elastic effect.
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Savvas Vassiliadis, Argyro Kallivretaki, Paraskevas Frantzeskakis and Christopher Provatidis
The purpose of this paper is to focus on the development of a thorough method for the macromechanical analysis of fabrics.
Abstract
Purpose
The purpose of this paper is to focus on the development of a thorough method for the macromechanical analysis of fabrics.
Design/methodology/approach
The homogenization method was implemented for the generation of continuum equivalent model for the plain woven structure. Keystone of the method is the mesomechanical analysis of the textile unit cell for the evaluation of the apparent properties and the generation of an equivalent macromechanical model supporting the mechanical performance of the structure. The finite element method (FEM) using beam elements was applied for the mechanical analysis of the discrete model of the unit cell and the FEM using shell elements was applied for the analysis of the continuum macromechanical model.
Findings
The tensile, shear and bending test of the unit cell were simulated. The constitutive equations of the continuum model were formed considering equivalent performance with the discrete model.
Originality/value
The reliability of the equivalent model in tensile, shear (in‐plane) and bending (out‐of‐plane) deformation was achieved even for asymmetric woven structures. The low computational power demanded for the meso‐ and macro‐mechanical modelling and analysis is a beneficial feature of the proposed method.
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Roberto Junior Algarín Roncallo, Luis Lisandro Lopez Taborda and Diego Guillen
The purpose of this research is present an experimental and numerical study of the mechanical properties of the acrylonitrile butadiene styrene (ABS) in the additive manufacturing…
Abstract
Purpose
The purpose of this research is present an experimental and numerical study of the mechanical properties of the acrylonitrile butadiene styrene (ABS) in the additive manufacturing (AM) by fused filament fabrication (FFF). The characterization and mechanical models obtained are used to predict the elastic behavior of a prosthetic foot and the failure of a prosthetic knee manufactured with FFF.
Design/methodology/approach
Tension tests were carried out and the elastic modulus, yield stress and tensile strength were evaluated for different material directions. The material elastic constants were determined and the influence of infill density in the mechanical strength was evaluated. Yield surfaces and failure criteria were generated from the tests. Failures over prosthetic elements in tridimensional stresses were analyzed; the cases were evaluated via finite element method.
Findings
The experimental results show that the material is transversely isotropic. The elasticity modulus, yield stress and ultimate tensile strength vary linearly with the infill density. The stresses and the failure criteria were computed and compared with the experimental tests with good agreement.
Practical implications
This research can be applied to predict failures and improve reliability in FFF or fused deposition modeling (FDM) products for applications in high-performance industries such as aerospace, automotive and medical.
Social implications
This research aims to promote its widespread adoption in the industrial and medical sectors by increasing reliability in products manufactured with AM based on the failure criterion.
Originality/value
Most of the models studied apply to plane stress situations and standardized specimens of printed material. However, the models applied in this study can be used for functional parts and three-dimensional stress, with accuracy in the range of that obtained by other researchers. The researchers also proposed a method for the mechanical study of fragile materials fabricated by processes of FFF and FDM.
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Examines the fifthteenth published year of the ITCRR. Runs the whole gamut of textile innovation, research and testing, some of which investigates hitherto untouched aspects…
Abstract
Examines the fifthteenth published year of the ITCRR. Runs the whole gamut of textile innovation, research and testing, some of which investigates hitherto untouched aspects. Subjects discussed include cotton fabric processing, asbestos substitutes, textile adjuncts to cardiovascular surgery, wet textile processes, hand evaluation, nanotechnology, thermoplastic composites, robotic ironing, protective clothing (agricultural and industrial), ecological aspects of fibre properties – to name but a few! There would appear to be no limit to the future potential for textile applications.
Details