Bidirectional Interface to SolidWorks Pacemaker Electrode Bidirectional Interface to SolidWorks

Capabilities of the Bidirectional Interface Associatively transfer geometry from the open active document, either part or assembly, in SolidWorks to COMSOL Multiphysics. Update geometry parameters in the open active document in SolidWorks. Set up an automatic parameter sweep for multiple geometry parameters. Take advantage of distributed memory systems, such as Windows and Linux clusters.

Model Definition The geometry represents a pacemaker electrode. Boundaries with applied positive potential. The geometry represents a pacemaker electrode. This model studies the heating effect of the current flowing through the surrounding tissue. Grounded boundaries. Cylinder representing the surrounding tissue.

Workflow Open the CAD file in SolidWorks. Transfer the geometry with the interface. Set up and solve the model in COMSOL Multiphysics Draw additional geometry Define integration variable to evaluate the resistive heat Assign material properties Define boundary settings Create a mesh Solve the model. Study the effect of geometry design parameters on the solution either by manual or automatic parametric sweep.

The bidirectional interface always transfers the geometry in the open active document in SolidWorks.

In the COMSOL Multiphysics Model Navigator select the Conductive Media DC application mode.

In the COMSOL Multiphysics GUI select File>SolidWorks Connection>Initialize to transfer the geometry and initialize the connection between COMSOL Multiphysics and SolidWorks.

When the transfer is ready the geometry appears in the COMSOL Multiphysics GUI.

Use the drawing tools in COMSOL Multiphysics to create the geometry for the surrounding tissue.

To evaluate the total resistive heat in the tissue define a variable in the Subdomain Integration Variables dialog box.

Set the material properties in the Subdomain Settings dialog box.

Define the electric potential and grounded boundaries in the Boundary Settings dialog box.

Click the Solve button to solve the model. Slice plot of the electric potential in the tissue surrounding the electrode.

Use the Plot Parameters dialog box to plot the resistive heating in the tissue.

Parametric Study Study the effect of design parameters on the resistive heating. Position of grounded region. Size of region where positive potential is applied.

Update of Geometry Parameters from the COMSOL Multiphysics GUI Define geometry parameters in SolidWorks and link to sketch dimensions. Define corresponding constants in COMSOL Multiphysics to which you can assign new values. Update the geometry from the COMSOL Multiphysics GUI. Geometry parameters and the geometry in SolidWorks document are updated and sent back to COMSOL Multiphysics Subdomain, boundary and mesh settings are associative and retained in the updated model. Solve the model again.

In the SolidWorks GUI select Equations from the Tools menu.

Click Add to enter a new equation.

Define the parameter, by giving it an appropriate value.

The parameter now appears in the list of equations. Also, the Equations folder appears in the tree indicating that the model contains equations. Use this folder to inspect and edit equations.

Add the second equation position=5

Click on a feature node to select it. Parameters belonging to the feature, including sketches, are displayed on the geometry.

Double click the dimension value to edit it.

Select the small arrow next to the value.

From the list that appears select Link Value.

From the Name list select the radius parameter.

A small symbol in front of the dimension shows that it is linked A small symbol in front of the dimension shows that it is linked. Notice that its name has also changed.

Perform similar steps to link the highlighted length dimension to the position parameter.

The SolidWorks geometry is now prepared for parameter update through the bidirectional interface.

In the COMSOL Multiphysics GUI select Constants from the Options menu.

Enter the constants radius and position and their new values 1 and 12, respectively. These correspond to the geometry parameters defined in SolidWorks. During update of the geometry these constants will be transfered to SolidWorks

Select File>SolidWorks Connection>Update to transfer the constants and to initiate an update of the geometry in SolidWorks.

When the transfer is ready the updated geometry appears in the COMSOL Multiphysics GUI.

In the SolidWorks GUI the parameters and the geometry have been updated.

Click the Solve button in the COMSOL Multiphyiscs GUI to obtain the new solution.

Parametric Sweep Automatically solve the model for a range of geometry parameters. Obtain a log-file containing design parameters and selected global variables evaluated for each solved model. Optionally save each solved model as an .mph file.

Select File>SolidWorks Connection>Geometric Parametric Sweep to set up and automatically solve the model for a range of geometry parameters.

Enter a name for the log file and list the variables to be evaluated. Enter a list of geometry parameters, and a range of values Click Solve to start the sweep. You can also select to save each solved model file separately.

Extra Slides – Equations in SolidWorks

Parameter Names For feature and sketch dimensions Solidworks automatically generates names of the format D1@Feature1, where D1 refers to a dimension of Feature1, and Feature stands for either Sketch or a feature name, such as Extrude, Revolve, Fillet, etc. You can use this information to create an equation of the form ”D1@Feature1”=”myparameter” to assign a user defined parameter to a feature parameter.

Assembly Documents Define a parameter “myparameter” in the assembly document. You can update the value of this parameter through the bidirectional interface. Link this parameter to any feature on the assembly level. To link this parameter to a feature or sketch parameter in a part define an equation in the part document of the form: “D1@Feature1”=“myparameter@myassembly.sldasm”