Using Solid Edge to reverse engineering data points from Stress vs. Strain curve images

Often times, the supplier will have an image of curve, but no data points to how do you obtain the data points easily and somewhat accurately?

I've imported images into Solid Edge before, scaled them, and used them as profiles for my model (reverse engineering parts that had a lasered profile), so I figured why not use that technique to discretize the curve.

Step 1:  In a new part file, start a new sketch, and insert the image.

Step 2: You need to scale the image.  Since the Y axis has known values, I created a line that was 9000 inches long, then scaled the image to match.

Step 3: I then drew line segments to approximate the curve.

Step 4: Add coordinate dimensions to the endpoints of each line and you now have data points to use in your FEA software of choice.  Note, the X-axis dimensions in Figure 1 don't match my Solid Edge dimensions, which meant a scale factor must be used to calculate the respective strain value.

Step 5: I added these points into my nonlinear material in Femap.

Thanks for taking time to read this and let me know if you have any questions.

- David Haag


Tool for measuring rolling resistance

I saw these push/pull scales and thought of a use case...measure a Greenpower car's rolling resistance.

You could take an initial measurement to establish a baseline and then make changes, such as:

1. tweak the front wheel toe-in, and remeasure to see if rolling resistance was reduced.
2. evaluate the effect of having too much tension in the sprocket chain
3. evaluate different wheel bearings, wheel bearing grease, tire compounds/pressures, etc.

These are some examples of the frictional forces opposing the vehicles motion and if you can reduce or eliminate them, you have conserved energy (the battery), and can power the motor for a longer period of time!

push pull scales.PNG