Graphical Design

• This guide will explain how to use the i-ROM Sketcher.

• Open the project

  • Click on "Open Project" and navigate to the "Accelerometer_SingleSideClamped" folder.
  • Select "Accelerometer.iromproj" to open the file.
  • A window will open asking if you want to build the 3D model. Press "Yes".

• To avoid losing the original data, save the project as a new file.

  • Click on "Save Project" and "Save as".
  • Choose a new projectfile and modelfile name (e.g. "Accelerometer_test") and click "Save".

• Click on the "Sketcher" button to open the window.

Inside the Sketcher window⚓︎

• With the left mouse button pressed, drag across all the objects to select them.

• Then press "Delete" on your keyboard to create a blank canvas to work on.

• Draw the first shape.

  • Click on "Rectangle" and with the left mouse button pressed draw a rectangular shape.
  • Deselect the Rectangle tool by clicking on the button again or by pressing "Escape" on your keyboard.
  • Click on the created shape to select it.
  • In the "Properties" window change the Body Number to 0.
  • The size and position of the shapes can also be changed here by entering the corresponding numbers.

• Now, create a second rectangle inside the first one by repeating the steps above.
  • The size should be slightly smaller.
  • Change the Material Number to 2.

• Create a square next to the other shapes by repeating the steps above.
  • Leave some space in between. In the next steps, springs will be added there.
  • The x- and y-size should be the same.
  • Change the Body Number to 1.
  • Change the Material Number to 1.

• Add a spring connecting the shapes.
  • Inside the "Properties" panel, expand "Spring Settings" by double-clicking on it.
  • Change the Default Widthto 10.
  • Select "Springs", click on the right edge of the first shape and then on the left edge of the square.
  • Deselect the Springs tool by clicking on the button again or pressing "Escape" on your keyboard.

• Add a second spring composed of multiple parts.
  • Select the "Springs" tool again.
  • Click on the right edge of the first shape, below the first spring.
  • Recreate the shape shown in the figure below by clicking on the positions where you want to create a corner.
  • For the curved part, select "Arc" in the top right corner. Then set the center point of the curved spring on the spot marked with a red circle in the figure below.
  • After placing the curved part of the spring, select "Line" again to create the last part.
  • Deselect the Springs tool by clicking on the button again or pressing "Escape" on your keyboard.

• Add a comb area.
  • Click on "Comb" and select "AREAinnerf".
  • Click in the middle of the top edge of the square to place the comb.
  • Select the comb by clicking on it and change Orientation Angle to 90.
  • Adjust the other settings to your liking.

• Add a second comb by flipping the first one.
  • With the comb selected, click on "Mirror" and then select "Horizontal axis".
  • Place the mirroring axis in the middle of the square by clicking on the x-axis.
  • Press "Create" to generate the mirrored comb area.

• Add a perforation pattern.
  • Click on "Perforation" and select "Cartesian pattern of rectangles".
  • Then click inside the square shape.
  • Select the perforation pattern by right-clicking on it.
  • Adjust the position, size and amount of perforations in the "Properties" panel.

• Click on "Compile Model" to save and build the created model.

Sensor sketch and the real sensor model⚓︎

• Click on "Process Data" to open the Process Data Settings window.
  • Change Activate Corner Filletto False.
  • Change Activate Mask Etchingto False.
  • Change Activate Side Etchingto False.
  • Click on "Save".

• Click on "Build Solids" to generate the new model.
  • Scroll the mouse wheel to zoom in on the details.
  • Here you can see that there are sharp edges and corners.
  • This is how the shapes are created in the Sketcher.

• Click on "Build ROM", choose "Finite Element Model" and in "System components to compute" only select the first option.

• Go to the "Basis" tab above the "Model Tree" and have a look at the frequencies in the "Mode Selection" panel on the right. Table 1 lists those frequencies in the second column.

• Go back into the Process Data Settings window to undo the changes

  • Change Activate Corner Filletto True.
  • Change Activate Mask Etchingto True.
  • Change Activate Side Etchingto True.
  • Click on "Save".

• Click on "Build Solids" to generate the new model.

  • Now you can see that the edges and corners are rounded.
  • This represents the real sensor model.

• Click on "Build ROM" again and use the same settings as mentioned above.
• Then, in the "Basis" tab, look at the frequencies on the right again and compare them to the ones generated earlier. In Table 1 these are listed in the third column.