Multibody Dynamics: A Solidworks FAQ

1. What is the significance of fps?

fps denote frames per second; let's explain this with a small calculation with the internal geneva mechanism.

Let’s assume you are giving motor input to the driver wheel at 10rpm and simulating for 6 seconds. If you give 60 fps, what does it mean?

Motor input=10rpm

Time of simulation= 6 seconds

So, during the simulation period, the driver wheel completes 1 rotation.

1-rotation=360 degrees

Thus the driver wheel rotates 360degrees for 6 seconds,

then for 1-second⇒ 60 degrees/sec

Since we use 60 fps, 60 fps/60degree/sec= 1 frame/degree.

This means for each and every degree of rotation, a frame is captured. This frame is nothing but a calculation interval.

Thus by increasing the fps-value, we can get a good result.

3. What is Precise Contact?

By enabling precise contact, the solid body contact between the two bodies will be more accurately computed. Thus, you get better results. But  Precise contact will increase the computational time, so depending on the application and time constraint, Precise Contact will be used.

4. Why export data to spreadsheets?

SolidWorks will give you only the output plots 

Ex: Angular Displacement of the driver wheel,

if you want the exact data points of the graph or to extract data from the plot, then you can export the plot data to a spreadsheet to use that data for further study, such as superimposing the graphs for the various cases.

5. How to export data to spreadsheets?

Right-click on the plot ⇒ Show Plot(plot will occur in the display)

Again right, click on the plot⇒ Export to Spreadsheet

6. How to Superimpose the plots in Excel?

Superimposing the plots means you should make a number of plots appear in a single plot. This is done to compare the data and also for a good presentation of the output obtained for various cases.

Note: It is recommended to use Google Spreadsheets or MS-Excel Sheets.

To plot the superimposed plot, first, you should prepare the data sheet in the following format.

Select the data⇒ insert⇒ chart⇒ Line chart

7. What is the Difference between coincident and concentric mate?

Let’s take an example of the Planetary gear challenge to attach the planetary gears with the pins of the carrier,  you can do it in two ways.

a) Coincident mate:

If the coincident mate is given between the inner circular edge of the planetary gear and the outer circular edge of the pin of the carrier, then the planetary gear will only rotate.

b) Concentric mate:

If the concentric mate is given between the inner circular edge of the planetary gear and the outer circular edge of the pin of the carrier, then the planetary gear will rotate as well as translate. To arrest the translation motion, again, a coincident mate has to be given with respect to any of the planes/faces.

8. How to save the animation?

Using the ‘save animation’ option, we can save the motion analysis animation as an AVI file.

9. How to save the imported file from the design library?

Right-click on the imported design library part

Using the ‘open part’  option, the part is opened as a separate part file.

Using the file⇒ save option, the imported part file from the library can be saved as a separate part file.

10. How to change the appearance of the parts?

 Using ‘edit appearance ’, the appearance of the part files can be changed.

The above are the different appearances that can be filled to the part.