Mechanical Simulation for Electronic Products Mike Kuron
High Fidelity PCB Analysis
Printed Circuit Boards are geometrically complex — — —
Many layers with complex traces and vias Spatially varying material properties Challenging to accurately analyze!
Increasing power density demands require a more rigorous analysis approach
New Mechanical capability allows PCB trace and via geometry to be mapped onto structural and thermal meshes —
Trace import from ECAD file in Mechanical
Analogous to existing Icepak capabilities
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PCB Analysis Workflow
Streamlined workflow for PCB analysis —
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SpaceClaim can now import ECAD files to define board geometry External data is used to specify trace and via files Local material properties are determined based on the percentage of copper within a given element
ECAD geometry •Ansoft ANF •Cadence BRD/MCM/SIP •ODB++ TGZ
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Import ECAD into ANSYS SpaceClaim
Map trace metal onto Mechanical model
•Create solid/shell geometry •Capture layer information
•Choose mapping resolution •Map onto any mesh
Run analysis in Mechanical •Thermal-Stress •Random vibration •Drop test etc.
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High Fidelity PCB Analysis
Trace mapping facilitates more accurate PCB models in less time —
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Thermal-stress Vibration Fatigue
PCB Geometry with defined layers in ANSYS SpaceClaim
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Plot of PCB strain, accurate trace mapping means detailed results
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v17 Workbench and Mechanical Features Pat Cunningham
Model Assembly
Model assembly (drag and drop of multiple Mechanical models) has been enhanced to include: — — — —
Remote Points Springs Beam Connections Point and Distributed masses
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External Model Utility
Material data is now transferred through the External Model utility. —
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ANSYS cdb, ABAQUS inp, and NASTRAN bdf file supported. Supports most material models that have a template in the Engineering Data window. • Temperature dependent isotropic and orthotropic data is transferred. • MISO and MKIN is not used in WB and therefore not supported (use TB, PLAS instead).
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Material Colors in Engineering Data
Engineering Data includes a new column to display the material color and allows user to assign new colors User can modify the color by clicking the drop-down icon, a color wheel window pops up for color selection
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External Model Utility
The following items have been added at v17: —
BEAM and PIPE elements: • ANSYS BEAM188, BEAM189, PIPE288, PIPE289 • NASTRAN CBAR and CBEAM • ABAQUS *BEAM SECTION, *FRAME SECTION, and *BEAM GENERAL SECTION
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Nodal and Element Components Coordinate systems
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External Model: Vertex Insertion Angle
External Model property ‘Vertex Insertion Angle’ allows users to insert a vertex if two free edges of the mesh make an angle greater than the specified value. Defaults to 60 degrees.
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Upcoord Capabilities in WB
Deformed mesh results can be updated and used as initial geometry for subsequent analyses. This is accomplished by dragging the Solution row of the deformed system onto the Model row of the receiving system.
New stress free geometry www.caeai.com
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Upcoord Capabilities in WB
The result to be used for the updated geometry is specified in the Solution properties of the original. Mode numbers (buckling and modal), result times, and scale factors are available.
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Reset Views on Geometry Refresh
Ever notice that Mechanical resets your graphics whenever you update geometry? Good news! You can shut that off in the Mechanical Tools > Options menu.
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Grouping in Mechanical
Grouping (folders) are now available throughout the Tree Outline. In case you missed it, CAE Associates’ recent eLearning seminar “Top 10 Cool Features in Mechanical” demonstrated many uses for object grouping. Shameless plug: Check it out on our website or YouTube channel!
https://caeai.com/resources/top-ten-cool-features-mechanical-ansys-e-learning https://www.youtube.com/watch?v=VS5LN1yG5oI
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Geometry Export from Mechanical
There are two geometry export options in Mechanical that can be used for reverse engineering: 1.
Geometry can be exported to a Part Manager Database (.pmdb) file. This file can be loaded into DesignModeler for editing.
file.pmdb
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Geometry Export from Mechanical
Geometry export options (continued) 2.
STL Export is now available for the Mesh view and any solved result (with deformed shape). STL files can be loaded into ANSYS SpaceClaim Design Modeler and reverse engineered. Undeformed mesh or Deformed result from Mechanical
STL import in SCDM
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Redesign in SCDM
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Named Selections
Named Selection Worksheet Summary Page has been added.
Named Selection criteria have added: — — —
body name surface body thickness “Convert To” can select upward (vertices to edges and edges to surfaces, e.g. “lslk” and “asll” in MAPDL).
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Contact Generation
Cylindrical faces can included, omitted, or used only in automatic contact generation. Useful for situations where contact between the body of a fastener and a hole could be controlled.
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Mesh Size Functions
Global Mesh Sizing defaults: —
Previous setting of Off is now called Adaptive
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Size Function defaults to Curvature for shell models, otherwise Adaptive.
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Mechanical Nonlinear Physics Preference
New physics preference for Non-Linear Mechanical Analysis: —
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Tightens defaults for meshing parameters. Introduced new shape checking criteria, “Nonlinear Mechanical”. Results in higher quality mesh compared to other shape checking criteria. Shape checking
Standard Mechanical
Non-Linear Mechanical
Minimum Jacobian
-100
1
Maximum Jacobian
457
8.3
Maximum Skewness
0.99988
0.992
# Elements
4,417
19,538
# Nodes
7,596
33,942
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Standard
Non-Linear
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Physics Preference Defaults
The default settings for the Mechanical and Nonlinear Mechanical Physics Preferences can be found in the Meshing User’s Guide.
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Mesh Connections
Can enable parallel meshing in situations where shared topology (“Formed Part”) would normally be used. — —
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In place of a Formed Part bodies with contact regions are meshed in parallel. The contact regions are converted to mesh connections after the meshing process is complete. Contact elements are not generated. Limited to tetrahedral meshes in 3D.
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Mesh Display By Body Connection
Useful display tool for checking shared topology mesh and merged mesh connections. Default mesh display Turning wireframe mode on
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Non-Linear Diagnostics
A new Solution Information object enables you to identify and view elements on your model that have failed to meet certain solver criteria. Named Selection objects will be created after a solution for the elements that violate the following criteria: — — — —
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Large distortion (HDST) Nodes with near zero pivots (PIVT) Large plastic/creep increment Mixed u-P constraints are not satisfied Hyperelastic element (EPHY), cohesive zone material (EPCZ), or damage strain (EPDM) not converged
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Solution Statistics in Mechanical
Contact Trackers are “Enhanced” by default meaning that they can be inserted and modified while the solution is on-going.
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Solution Statistics in Mechanical
The following quantities have been added to the Solution folder details: —
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MAPDL Elapsed Time MAPDL Memory Used MAPDL Result Size
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Mesh Nonlinear Adaptivity
What is Nonlinear Adaptivity?
A tool for solving highly nonlinear problems that would otherwise fail to converge due to element distortion. Automatically remeshes regions where elements have become highly distorted.
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What is Nonlinear Adaptivity?
Nonlinear Adaptivity is available in both Mechanical and MAPDL. It is limited to the following lower order elements: — —
PLANE182 (2D 4-node quad) SOLID285 (3D 4-node tet)
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What is Nonlinear Adaptivity?
To activate a “Nonlinear Adaptive Region” object is added to the analysis folder. The control can be defined on a per load step basis.
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What is Nonlinear Adaptivity?
The Mechanical options include: —
— —
Energy (update the mesh based on an energy coefficient) Box (update the mesh in the region specified) Mesh (update based on a maximum allowable corner angle)
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What is Nonlinear Adaptivity?
Remesh points are displayed in the force convergence plot. The result items include a column indicating where the adaptive refinement occurred.
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What is Nonlinear Adaptivity?
Remesh points are also visible when the result is animated.
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What is Nonlinear Adaptivity?
Details for Mechanical and MAPDL can be found in the help documentation:
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