Read Advanced Techniques For Greater Accuracy, Capacity and Speed Using Maxwell v11 text version

Advanced Techniques for Greater Accuracy, Capacity, and Speed using Maxwell 11

Julius Saitz Ansoft Corporation

Overview

· · · · · · · Curved versus Faceted Surfaces Mesh Operations Data Link Advanced Field Plotting Techniques Scripting Magnetization modeling Useful hints

Curved vs. Faceted Surfaces

· The Maxwell 11 interface encourages the use of curved surfaces · Many CAD programs use curved surfaces · Curved surfaces do not directly translate into a better solution, due to the nature of the finite tetrahedral mesh elements ­ there is always some deviation from the curved surface and the meshed surface · Using faceted surfaces can be more robust in many cases · Faceted surfaces may converge in fewer iterations and may use fewer mesh elements ­ therefore, there is a possible large speed improvement!

Curved vs. Faceted Surfaces

Curved Faceted

Curved vs. Faceted Surfaces

· Calculate force until 1% force change and 1% Energy Error Curved Initial mesh (tets) Adaptive Passes Final mesh (tets) Simulation Time 3331 9 22020 03:53 min Faceted 1535 7 7484 01:08 min

Mesh Operations

· Mesh operations provide a tool of manually refining the mesh in/on selected objects · The mesh determines both the field solution as well as the consistency of the results ­ mesh operations can be used to assist both · The initial mesh is determined by the geometry only ­ mesh operations improve the mesh consistency and improve the solution process ­ this is especially important for transient simulations · Importing or linking a mesh is an advanced mesh technique that allows for efficient mesh use · To assign different mesh operation select an object or face and choose Maxwell > Mesh Operations > Assign

Mesh Operations ­ Surface Approximation

Mesh Operations ­ Surface Approximation

Initial Surface Normal Deviation ­ 5 deg (default 15 deg) Maximum Aspect Ratio ­ 3 (default 10) Both

Mesh Operations ­ Skin Depth Based

Mesh Operations ­ Skin Depth Based

Initial Top and bottom face Side face

Mesh Operations ­ Model Resolution

Small box subtracted from the cylinder

Mesh Operations ­ Model Resolution

· Select the object and specify the size of the small feature that needs to be ignored

Mesh Operations ­ Model Resolution

No model resolution Model resolution larger that the small box edge length

Data Link - Mesh

· For identical geometries Maxwell allows to reuse the existing mesh in another Design or Project through the Data Link · As an example consider a solenoid which we wish to solve at two different current levels for the same position of the armature: I1 = 1000 At I2 = 5000 At

Data Link - Mesh

1) Solve Design 1 (5000 At) using adaptive technology 2) Link mesh from Design 1 to Design 2 3) Solve Design 2 (1000 At)

Data Link - Mesh

Data Link - Mesh

2) Link losses (Joule and possibly core) from Maxwell to ePhysics) 1) Solve Eddy Current problem in Maxwell

3) Solve ePhysics problem for temperature distribution

Advanced Field Plotting Techniques

· Multiple windows can be opened and arranged to show geometry, field plots, 2D and 3D graphs and tables · Multiple field plots can be created, overlaid and displayed in flexible and general formats · Field plots can be animated and exported · Any quantity that can be derived from the solved quantities can be plotted using the functionality of the Fields Calculator

Multiple windows

Multiple plots

Fields Calculator

· Allows to define any arbitrary expression by manipulating computed field quantities and geometrical and mathematical functions · Example: radial component of B Brad = Bx*cos(phi) + By*sin(phi)

Plot on a line

· Any calculated quantity or expression defined in the Fields Calculator can be plotted on a line or surface

Multiple windows with multiple plots

Surface plot - tone

· Color varies continuously between isovalues

Surface plot - lines

· Lines are drawn along the isovalues

Surface plot ­ outlined fringe

· Color is constant between isovalues

Multiple surface plot

Animation of slice plots

Transient animation

Current density plot

Transient animation

Scripting

· Scripting is a powerful tool of automation · In Maxwell everything starting from preprocessing (geometry creation), materials and boundary assignment, through analysis setup, ending with post-processing and export of data can be scripted · VB Script used by default (Tools > Record/Run Script) · Matlab and Java Scripts can be used if desired

Scripting ­ VB Script

· Simple example: create a regular polyhedron

Scripting ­ Matlab

· Replace CreateObject command with actxserver():

Set oAnsoftApp = CreateObject("AnsoftMaxwell.MaxwellScriptInterface") iMaxwell = actxserver('AnsoftMaxwell.MaxwellScriptInterface');

· Remove Set from the Object definitions:

Set oDesktop = oAnsoftApp.GetAppDesktop() Desktop = iMaxwell.GetAppDesktop();

· Use Invoke to execute the command:

oEditor.CreateRegularPolyhedron invoke(Editor, 'CreateRegularPolyhedron', ...

Scripting ­ Matlab

· Replace all Arrays with the proper elements enclosed in { }:

Array("NAME:CylinderParameters,... {'NAME:CylinderParameters',...

· End Maxwell session with:

Delete(iMaxwell)

· For any strings replace " with `

Scripting ­ Matlab

· Simple example: create a regular polyhedron

User Defined Primitives

· Allow automated creation and parameterization of complicated geometrical structures

Radial Magnetization

Radial Magnetization

· Create 2 magnet materials ­ positive and negative direction of magnetization (R component + 1 and -1) · Choose Cylindrical material coordinate system type

Parallel Magnetization

Parallel Magnetization

Parallel Magnetization

Parallel Magnetization

· · · · Create 2 magnet materials ­ positive and negative direction of magnetization (X or Y component + 1 and -1) Choose Cartesian material coordinate system type Create as many rotated or face coordinate systems as many there are magnets in the design Associate each magnet with appropriate coordinate system

Arbitrary Magnetization - Script

· · · · Create as many magnet segments as desired (magnet discretization) Create as many different materials as many there are segments Each material will have a unique Coercive Field, Relative Permeability and Direction of Magnetization Assign appropriate material to each magnet segment

Arbitrary Magnetization - Script

Spin

· Observe the geometry or field plot on a self-rotating model · View > Spin

Select All Object Faces

· Objects may consist of many faces that need to be selected typically for boundary assignment · Edit > Select > All Object Faces

Visualize History of Objects

· Visualization is updated on subsequent history playback · Tools > Options > 3D Modeler Options > Display Tab

Point and Dialog Entry Modes

· Editing properties of new primitives: use F3 and F4 to switch between Point and Dialog entry modes

Dialog entry mode window

Maxwell Keyboard Shortcuts

General Shortcuts F1: Help Shift + F1: Context help CTRL: + F4: Close program CTRL + C: Copy CTRL + N: New project CTRL + O: Open... CTRL + S: Save CTRL + P: Print... CTRL + V: Paste CTRL + X: Cut CTRL + Y: Redo CTRL + Z: Undo CTRL + 0: Cascade windows CTRL + 1: Tile windows horizontally CTRL + 2: Tile windows vertically 3D Modeller Shortcuts B: Select face/object behind current selection F: Face select mode O: Object select mode CTRL + A: Select all visible objects CTRL + SHIFT + A: Deselect all objects CTRL + D: Fit view CTRL + E: Zoom in, screen center CTRL + F: Zoom out, screen center CTRL + Enter: Shifts the local coordinate system temporarily SHIFT + Left Mouse Button: Drag Alt + Left Mouse Button: Rotate model Alt + SHIFT + Left Mouse Button: Zoom in / out F3: Switch to point entry mode (i.e. draw objects by mouse) F4: Switch to dialogue entry mode (i.e. draw object solely by entry in command and attributes box.) F6: Render model wire frame F7: Render model smooth shaded Alt + Double Click Left Mouse Button at points on screen: Sets model projection to standard isometric projections (see diagram below). ALT + Right Mouse Button + Double Click Left Mouse Button at points on screen: give the nine opposite projections.

Predefined View Angles Top

Left

Right

Bottom

Summary

· · · Curved surfaces can be conveniently used in Maxwell 11, however, their usage may slow down the mesh generation and solution process Maxwell 11 comes with variety of different Mesh Operations that provide opportunities for user to control the mesh generation if desired Data Link technology in Maxwell 11 allows powerful data exchange between different projects and designs within Maxwell as well as between Maxwell and other Ansoft products (e.g. Maxwell ­ ePhysics) Any basic quantity along with any arbitrarily defined expression in Fields Calculator can be graphically displayed using range of Field Plotting Techniques available in Maxwell 11 Maxwell 11 is fully scripted which makes from this simulation software a powerful tool of design automation

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Advanced Techniques For Greater Accuracy, Capacity and Speed Using Maxwell v11

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