I had a local wheel manufacturer in the bay area test the rear wheel that was a damaged one donated to me, and they put 2,000 pounds on the end of a 6 foot pole and mounted it to the wheel, and cycled it 100,000 times, to look for cracking, and there was no cracking. But I still decided to only have it on my car because of potential liability problems. I did not want my manufacturing company to go up in smoke from making 100 sets of wheels, and possibly making $50,000 in profit only to see it disappear, when one lawsuit for millions would wipe me out. You see all of the crashes talked about on this site, and if one happens, and they can not figure out why, and then they see the wheels were modified from OEM, and they decide to blame them, even thought that was not the reason, well you get my drift. So I stuck to machining valve covers, and third brake light covers, and jewelry and trivets for the women. Not much liability there???
It's an interesting result Dennis. I ran a quick analysis tonight (took about 10 minutes to complete with a coarse mesh) on stress on both designs, general aluminum material, well over 1500 lbs of a lateral load around the rim (noting the tire patch contact moment is applied on the tire diameter), but for a rudimentary test.. here are the 3D graphical stress mapped results.
The original wheel has very rigid spokes, so the wheel does not flex around the spokes, therefore flexing mostly around the hub section, the region in red is exposed to the most stress.
In your cutout design, the spokes are now more flexible, soaking up more of the stress from the hub section, and the peak stresses are in the corners of the dog bone cutouts. This material stress is much higher than the stock wheel, compare the values. I predict this is where the rim would crack. Don't compare the colors by color quantity, compare the values associated to the colors and distribution of the stress. Peak stress is 4.65 on the stock wheel and 7.88 on the modified wheel, which is almost double. Therefore, the immediate conclusion is that this cutout wheel is much weaker regarding this dirty analysis. Obviously yield strength of material is unknown, but these values are going way beyond typical yield strength of typical untreated forged aluminum material.
For others not familiar with design / engineering.. the goal is to
distribute stress throughout the part. The solution is not always to stiffen a region that is under high stress, the solution may be to remove material in other areas to help relieve stress in weaker areas. Stress is internal / surface material pressure / compression or tension. Yet, in this case, removing material is this location of the spokes has negative effects.
I would definitely not recommend cutting your wheels. This is just a quick illustrated analysis on a random CAD model that does not represent the real part or material properties & thickness, the stress is very high and may crack, and there are many other tests and dynamic situations (i.e. turning while hitting a *** hole) required to determine & validate strength of a part.
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Here's some results on the previous quick designs.. as you can see the peak concentrated stress is 6.80 for the Y multi spoke, 6.45 for the 6 spoke and 6.25 for the 12 spoke wheel, so they all still need some work to be as strong as the stock 2000 wheel design that had a low stress value of 4.65
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