Influences of material degradation due to laser cutting on the operating behaviour of PMSM using a continuous local material model

Using an unified approach based on the local material symmetry group introduced for general first- and second-order strain gradient elastic media, we analyze the constitutive equations of strain gradient fluids. For the strain gradient medium there exists a strain energy density dependent on first- and higher-order gradients of placement vector, whereas for fluids a strain energy depends on a current mass density and its gradients. Both models found applications to modeling of materials with complex inner structure such as beam-lattice metamaterials and fluids at small scales. The local material symmetry group is formed through such transformations of a reference placement which cannot be experimentally detected within the considered material model. We show that considering maximal symmetry group, i.e. material with strain energy that is independent of the choice of a reference placement, one comes to the constitutive equations of gradient fluids introduced independently on general strain gradient continua.

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Identification of Mode Shapes of a Composite Cylinder Using Convolutional Neural Networks

Materials ◽

10.3390/ma14112801 ◽

2021 ◽

Vol 14 (11) ◽

pp. 2801

Author(s):

Bartosz Miller ◽

Leonard Ziemiański

Keyword(s):

Neural Networks ◽

Convolutional Neural Networks ◽

Composite Structures ◽

Three Dimensional ◽

Mode Shapes ◽

Identification Algorithm ◽

Material Degradation ◽

Local Material ◽

Noisy Input ◽

Shape Vector

The aim of the following paper is to discuss a newly developed approach for the identification of vibration mode shapes of multilayer composite structures. To overcome the limitations of the approaches based on image analysis (two-dimensional structures, high spatial resolution of mode shapes description), convolutional neural networks (CNNs) are applied to create a three-dimensional mode shapes identification algorithm with a significantly reduced number of mode shape vector coordinates. The CNN-based procedure is accurate, effective, and robust to noisy input data. The appearance of local damage is not an obstacle. The change of the material and the occurrence of local material degradation do not affect the accuracy of the method. Moreover, the application of the proposed identification method allows identifying the material degradation occurrence.

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Considering multiple process observables to determine material model parameters for FE-cutting simulations

The International Journal of Advanced Manufacturing Technology ◽

10.1007/s00170-021-06845-6 ◽

2021 ◽

Author(s):

Marvin Hardt ◽

Thomas Bergs

Keyword(s):

Chip Thickness ◽

Material Model ◽

Experimental Investigations ◽

Model Parameters ◽

Inverse Approach ◽

Local Material ◽

Novel Approach ◽

Validation Parameters ◽

Multiple Process ◽

Cutting Simulations

AbstractAnalyzing the chip formation process by means of the finite element method (FEM) is an established procedure to understand the cutting process. For a realistic simulation, different input models are required, among which the material model is crucial. To determine the underlying material model parameters, inverse methods have found an increasing acceptance within the last decade. The calculated model parameters exhibit good validity within the domain of investigation, but suffer from their non-uniqueness. To overcome the drawback of the non-uniqueness, the literature suggests either to enlarge the domain of experimental investigations or to use more process observables as validation parameters. This paper presents a novel approach merging both suggestions: a fully automatized procedure in conjunction with the use of multiple process observables is utilized to investigate the non-uniqueness of material model parameters for the domain of cutting simulations. The underlying approach is two-fold: Firstly, the accuracy of the evaluated process observables from FE simulations is enhanced by establishing an automatized routine. Secondly, the number of process observables that are considered in the inverse approach is increased. For this purpose, the cutting force, cutting normal force, chip temperature, chip thickness, and chip radius are taken into account. It was shown that multiple parameter sets of the material model can result in almost identical simulation results in terms of the simulated process observables and the local material loads.

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Iron loss simulation using a local material model

COMPEL The International Journal for Computation and Mathematics in Electrical and Electronic Engineering ◽

10.1108/compel-10-2018-0421 ◽

2019 ◽

Vol 38 (4) ◽

pp. 1224-1234

Author(s):

Benedikt Groschup ◽

Silas Elfgen ◽

Kay Hameyer

Keyword(s):

A Priori ◽

Material Model ◽

Edge Length ◽

Iron Loss ◽

Local Magnetization ◽

Content Type ◽

Local Loss ◽

Cut Edge ◽

Iron Losses ◽

Local Material

Purpose The cutting process of the electric machine laminations causes residual mechanical stress in the soft magnetic material. A local magnetic deterioration can be observed and the resulting local and global iron losses increase. A continuous local material model for the consideration of the changing magnetization properties has been introduced in a previous work as well as an a priori assessment of iron losses. A local iron loss calculation considering both a local magnetization and local loss parameters misses yet. The purpose of this study is to introduce a local iron loss calculation model considering both a local magnetization and local loss parameters. Design/methodology/approach In this paper, an approach for local iron loss simulation is developed and a comparison to the cut-edge length-dependent loss model is given. The comparison includes local loss distribution in the lamination as well as the impact on the overall motor efficiency and vehicle range in an electric vehicle driving cycle. Findings For an analysis of the resulting local iron loss components, both the local magnetization and iron loss parameters must be considered using physically based models. Consistently, a local iron loss model is presented in the work. The developed model can be used to gain detailed information of the local loss distribution inside the machine. The comparability of this local iron loss with the cut-edge length approach for overall system characteristics, e.g. efficiency or driving range, is shown. Originality/value A local iron loss simulation approach is a physical accurate model to describe the influence of cutting techniques on electric machine characteristics. A comparison with the less complicated a priori assessment gives detailed information about the necessity of the local model under consideration of the given problem.

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Cutting Parameters for the Reduction in Material Degradation in the Laser Cutting of Advanced High-Strength Steels

Proceedings of the Institution of Mechanical Engineers Part B Journal of Engineering Manufacture ◽

10.1243/09544054b12304 ◽

2006 ◽

Vol 220 (6) ◽

pp. 877-882 ◽

Cited By ~ 3

Author(s):

A Lamikiz ◽

L N López de Lacalle ◽

J A Sánchez ◽

D del Pozo ◽

J M Etayo ◽

...

Keyword(s):

Laser Cutting ◽

High Strength Steels ◽

High Strength ◽

Cutting Parameters ◽

Material Degradation ◽

Advanced High Strength Steels

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Space Mapping Optimization of the Magnetic Circuit of Electrical Machines Including Local Material Degradation

IEEE Transactions on Magnetics ◽

10.1109/tmag.2007.893409 ◽

2007 ◽

Vol 43 (6) ◽

pp. 2609-2611 ◽

Cited By ~ 42

Author(s):

Guillaume Crevecoeur ◽

Luc Dupr ◽

Rik Van de Walle

Keyword(s):

Magnetic Circuit ◽

Space Mapping ◽

Electrical Machines ◽

Material Degradation ◽

Local Material

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Combining adhesive contact mechanics with a viscoelastic material model to probe local material properties by AFM

Soft Matter ◽

10.1039/c7sm02057k ◽

2018 ◽

Vol 14 (1) ◽

pp. 140-150 ◽

Cited By ~ 12

Author(s):

Christian Ganser ◽

Caterina Czibula ◽

Daniel Tscharnuter ◽

Thomas Schöberl ◽

Christian Teichert ◽

...

Keyword(s):

Surface Roughness ◽

Atomic Force Microscopy ◽

Viscoelastic Material ◽

Material Properties ◽

Material Model ◽

Adhesive Contact ◽

Force Microscopy ◽

Atomic Force ◽

Local Material ◽

Local Material Properties

We present an atomic force microscopy based method to study viscoelastic material properties at low indentation depths with non-negligible adhesion and surface roughness.

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A Multiscale Approach to Polycrystalline Materials Damage and Failure

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.627.33 ◽

2014 ◽

Vol 627 ◽

pp. 33-36 ◽

Cited By ~ 1

Author(s):

Ivano Benedetti ◽

M.H. Aliabadi

Keyword(s):

Three Dimensional ◽

Polycrystalline Materials ◽

Multiscale Approach ◽

Damage Localization ◽

Dimensional Approach ◽

Material Degradation ◽

Component Level ◽

Damage And Failure ◽

Local Material ◽

Macro Scale

A two-scale three-dimensional approach for degradation and failure in polycrystalline materials is presented. The method involves the component level and the grain scale. The damage-induced softening at the macroscale is modelled employing an initial stress boundary element approach. The microscopic degradation is explicitly modelled associating Representative Volume Elements (RVEs) to relevant points of the macro continuum and employing a cohesive-frictional 3D grain-boundary formulation to simulate intergranular degradation and failure in the Voronoi morphology. Macro-strains are downscaled as RVEs' periodic boundary conditions, while overall macro-stresses are obtained upscaling the micro-stress field via volume averages. The comparison between effective macro-stresses for the damaged and undamaged RVEs allows to define a macroscopic measure of local material degradation. Some attention is devoted to avoiding pathological damage localization at the macro-scale. The multiscale processing algorithm is described and some preliminary results are illustrated.

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