Technical LibraryArticle: JMAG A to Z

Issue 5 Understanding Material Modeling from A to Z

Have you mastered JMAG?
JMAG continues to evolve with each passing day. There may be functions in JMAG that even those who are already using it will learn for the first time, as well as some useful procedures that are not well known yet. Why don't we make operations more efficient by becoming familiar with new functions and operations that we don't know about?
In this series, I would like to introduce "Things that we should know" in JMAG, as well as some advantageous applications that you can try.

Overview

Precise material modeling is one of the factors that can significantly affect the accuracy of a variety of analyses, including electromagnetic field analysis. Most people, however, feel that it requires a lot of time and experience to create precise material modeling that reproduces the behavior of materials by assigning each material property to each analysis objective.
JMAG-Designer has developed material modeling that is not only easy to handle, but can also model the behavior of materials more accurately and easily.
In this issue, I will introduce functions for material modeling in JMAG-Designer that can help make operations more efficient. By all means, use this opportunity to take your modeling abilities to the next level.

Management of Material Properties Using the Material Database

JMAG-Designer provides a material database that includes many material properties that are frequently used in electromagnetic field analysis. The material properties do not need to be modeled for each analysis because they are defined independently. All materials that can be used are displayed in [Toolbox] > [Materials] (on the right side of the screen), and are categorized by manufacturer, material type, etc. (Fig. 1). JMAG has more than 700 types of materials from 14 companies, giving a wide range of material data provided by the leading material manufacturers. This data can be used directly in simulations.
The properties of the materials can be viewed by right-clicking a material in the material list. Select [Details] if the material is provided by a manufacturer, or select [Edit] if the material has been created by a user. After this, the properties of the selected material are displayed in the [Material Editor].
JMAG-Designer defines material properties by dividing them into five categories: "Magnetic Properties," "Electric Properties," "Mechanical Properties," "Thermal Properties," and "Iron Loss Properties." Because these various properties are collectively defined to a material, the material data can be used jointly in different analyses, such as a magnetic field analysis and a thermal analysis. It is especially useful for a coupled analysis.
The numerical data of a material's magnetic properties and iron loss properties are concealed if it has been provided by a manufacturer, but they can be viewed in a graph. This graph can be enlarged by clicking and dragging the mouse across it, and the detail of its display can be customized by specifying an axis range or grid line from the graph properties (Fig. 2).

Fig. 1 Material database
Fig. 1 Material database


Fig. 2 Property graph of a material provided by a manufacturer
Fig. 2 Property graph of a material provided by a manufacturer

Defining Original Material Properties

Of course, your own material properties can be added to the material database in JMAG. A material that is either not in the material database or is based on a measured value can be created. Because the material is added to the material database, it does not need to be modeled for each analysis. To define your own material properties, set their values after creating a custom material.

Creating a Custom Material

A custom material can be created by right-clicking [Custom Materials] in the materials list and selecting [Create New] (Fig. 3). The following five categories of properties can be defined, like with the materials provided by manufacturers.

  1. Magnetic Properties
    Select the material type first in this category.
    The magnetic properties can be defined for a permanent magnet. Temperature dependent properties such as [Nonlinear (Reversible / Temperature Dependent)] and [Nonlinear (Irreversible / Thermal Demagnetization)] can be defined as its magnetic property.
    Both the anisotropy settings and the magnetic properties can be defined for a soft magnetic material. The temperature dependent and stress dependent properties can be defined as its magnetic property.
    These properties are used in a magnetic field analysis.
  2. Electric Properties
    The conductivity and permittivity can be defined in this category. These two properties are used in an electric field analysis, and the conductivity can be used in a magnetic field analysis, as well.
  3. Mechanical Properties
    Physical properties such as density and Young's modulus can be defined in this category. In addition to each component, the anisotropic properties can be defined by a matrix, as well.
    All of these properties are used in a structural analysis, and the density can be used in a magnetic field analysis and thermal analysis, as well.
  4. Thermal Properties
    The thermal conductivity and specific heat can be defined in this category.
    These two properties are used in a thermal analysis.
  5. Loss Properties
    The loss properties are used for iron loss calculations in a magnetic field analysis.
    Select the loss type, and then set the properties. The loss type can be selected from [Iron Loss Equation], [Hysteresis / Joule Loss Table] or [Iron Loss Table].

Fig. 3 Creating a custom material
Fig. 3 Creating a custom material

Importing External Material Data

Numerical table data like measurements or experience values can easily be imported to the properties when creating a custom material. Use the following three methods to import numerical table data to JMAG-Designer:

  1. Importing a numerical data table
    Though this is not limited to creating materials, the right-click menus of all [Edit Point Sequence] dialog boxes have an [Import] function. This function can import the numerical data table from a text or csv file (Fig. 4). Table data in programs such as Excel can also be copy-and-pasted into the [Edit Point Sequence] dialog box.
  2. Importing materials created with JMAG-Studio
    The hb, hbt, hbs and hbp files created in JMAG-Studio can easily be imported and used in JMAG-Designer. Select [Import Material] after right-clicking [Custom Materials] in the material list, or click the import button on the [Edit Point Sequence] dialog box.
  3. Installing the SMMA material database in JMAG-Designer
    JMAG has prepared an Excel macro tool that easily imports the magnetic steel sheet data provided by America's SMMA (The Motor & Motion Association) (Fig. 5). The Excel macro tool is in the following folder.
    (Installation folder)\sample \scripts
    [File name] MaterialDataConverter.xls
    For more information about the detailed operating procedures, open Help in JMAG-Designer and look at
    Analysis > Creating a Material (Using the Material Database) > Installing the SMMA Material Database in JMAG-Designer.

Fig. 4 Importing an external numerical data table
Fig. 4 Importing an external numerical data table


Fig. 5 Installing the SMMA material database
Fig. 5 Installing the SMMA material database

Defining the Material Properties for a Magnetization Analysis

JMAG can perform a magnetization analysis that reproduces magnetization distribution in a more realistic manner, allowing you to analyze the magnetization process in greater detail. Magnetic properties that define the magnetization distribution for the parts to be magnetized can be created as a material, referred to in JMAG as a "magnetization material."
Furthermore, the material model calculated by the magnetization analysis can be added to the material database as a "User Magnetization" material.

Creating a Magnetization Material

To create a magnetization material, select [Magnetization] as the material type in the [Magnetic Properties] category. The two properties can be defined to a magnetization material. The [Initial Magnetization Curve] defines the magnetic properties that are obtained by applying an external magnetic field to the parts to be magnetized. [Magnetization Ratio] and [Demagnetization Curve] define the behavior of incomplete magnetization.

Importing the User's Magnetization Material

After a magnetization analysis, the magnetization material that has been created is automatically added in the name of the study to the [User Magnetization] folder under [Permanent Magnet] in the material list. There is another method of doing this, however: A user magnetization material can also be added manually. Right-click [User Magnetization] and select the [Create New User Magnetized Material] to specify the calculated JCF file.
The calculated JCF file is then exported with the name "[input JCF file name] + _magnetized.jcf" to the folder where the magnetization analysis was run. If the magnetization analysis was run from JMAG-Designer, the [input JCF file name] is "Designer.jcf", so the calculated JCF file name is "Designer_magnetized.jcf". This JCF file is useful because it allows the same user magnetization material to be recreated in any computer.

Assigning Materials from the Material Database to an Analysis Model

To assign a material for a part, select the material from the material list and then drag-and-drop it to a target part. Although this is a simple operation, JMAG-Designer provides three ways to assign a material more efficiently.

Assigning to a Part in the Graphics Window

Select a material from the material list and then drag-and-drop it to the target part in the graphics window (Fig. 6).

Fig. 6 Assigning to a part in the graphics window
Fig. 6 Assigning to a part in the graphics window

Assigning to a Part in the Project Manager

You can also drag-and-drop the material to a part icon under [Study] > [Parts] in [Project Manager]. If an analysis model has complex geometry or many parts, it can be hard to assign to a target part in the graphics window. To avoid that trouble, this function can be used to assign a material directly to a target part while avoiding operations like rotating the model.

Assigning a Material in a Study to a Part

The materials added to the study (these are under [Study] > [Materials] in [Project Manager]) can be assigned to parts from the right-click menu: Select the part in the graphics window, right-click its material icon under [Study] > [Materials] in [Project Manager], and select [Apply to Selected] (Fig. 7).
This operation is useful when a material needs to be assigned to several parts. Select the parts that need to have the same material assigned to them in the graphics window, and then use this function.

Fig. 7 Assigning a material in a study to a part
Fig. 7 Assigning a material in a study to a part

Setting Part Properties for the Assigned Material

When a material is assigned to a part, a setting dialog box like [Material] or [Permanent Magnet] is displayed. The setting properties can be defined for each part in these dialog boxes. For example, this operation can be used for a part that needs to have a defined lamination direction that goes along with the magnetic properties of something like a laminated steel sheet. These properties can be used for precise material modeling in each analysis. JMAG-Designer provides highly precise and efficient material modeling by separating the properties that are material-specific from those that need to be defined for each part.

Soft Magnetic Material Properties

[Electric Properties], [Lamination] and [Magnetic Properties Correction] can be set for a soft magnetic material. [Loss Calculation] also can be set if a material has loss properties. Although an iron loss calculation can be performed in a separate loss study, it can also be performed in a magnetic study together with the magnetic field analysis. This requires that the [Iron loss Calculation] condition is set to the magnetic study and the loss calculation is assigned to the target material.

Permanent Magnet Properties

[Electric Properties], [Magnetization Pattern], [Magnetization Direction], [Skew], [Magnetic Properties Correction] and [Anisotropy Type] can be set for a permanent magnet.
[Transfer Table] can also be set if the material is one of the user's magnetization materials. [Transfer Table] is the mapping setting used when assigning a part in a different position from the magnet in a magnetization analysis. This function allows for general usage of the user's magnetization material.

Magnetization Properties

[Complete Magnetization] and [Material Type] need to be set first in the magnetization properties. There are three types of magnetization: Complete magnetization for isotropic magnetization material, incomplete magnetization for isotropic magnetization material, and incomplete magnetization for anisotropic magnetization material. In addition, the magnetization field and [Electric properties] can be set, as well. [Orientation] needs to be set for anisotropic magnetization material.

Useful Functions Using the Material Database

Although the material database is categorized by manufacturers and material types in the [Material] list, the large number of materials can make it time-consuming to find the material for each analysis. This is why JMAG-Designer provides convenient functions to help with using the material database.

Searching for Materials

The [Look For] text box can be used to filter a list of materials that are displayed by material name or manufacturer name. This makes it easier to find a material (Fig. 8).

Fig. 8 Searching for materials
Fig. 8 Searching for materials

Marking Functions

Frequently used materials can be selected quickly by using marking functions. There are two ways of marking:

  1. Adding to the bookmarks
    Adding frequently used materials to [Bookmarks] speeds up the search process because it makes them easier to find. To add a material to [Bookmarks], right-click the material and select [Add to Bookmarks].
  2. Adding to the study
    Materials can be added to a study without assigning them to a part. These materials under the study are saved in the project file, so custom materials can be used in computers other than your own.

These marking functions are closely linked to material parametric analysis because it is too hard to select a material if all of them are displayed. This is why JMAG-Designer only displays the materials under the study and [Bookmarks] when parametric analysis settings are involved (Fig. 9).

Fig.9 Marking functions in a material parametric analysis
Fig.9 Marking functions in a material parametric analysis

Temporary Folder

JMAG-Designer has a material database for each user account on a computer. How can a custom material be used on someone else's computer?
The JMAG-Designer project file (*.jproj files) also saves material properties under the study. Materials are saved by adding them to the study without assigning them to a part. When this project file is loaded by JMAG-Designer on another computer, the materials under the study will be added under [Temporary] in the material list. Right-click a material under [Temporary] and select [Move to custom] to move the material to [Custom Materials], and save it in the material database of that computer. Doing this makes it possible to share the custom material.

In Conclusion

In this issue, I took the opportunity to introduce JMAG-Designer's various material modeling functions. Were there some functions that you will be able to use to increase productivity or accuracy in your own work operations? By all means, take this opportunity to use them and get the maximum benefit from their application.
Next time I plan to introduce an A to Z for creating geometry. Be sure not to miss it.

(Masayuki Kawai)





Contents

Issue 11 Electric Field Analysis from A to Z
Issue 10 Structural Analysis from A to Z
Issue 9 Understanding Thermal from A to Z
Issue 8 Understanding Conditions from A to Z
Issue 7 Understanding Conditions from A to Z
Issue 6 Understanding Geometry Modeling from A to Z
Issue 6 Understanding Geometry Modeling from A to Z
Issue 4 Understanding Meshes from A to Z
Issue 3 Shortening Calculation Time from A to Z
Issue 2 Evaluating Results and Viewing Models from A to Z
Issue 1 Running Multiple Case Calculations from A to Z

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