[(-D]
http://www.sciencedirect.com/science/article/pii/S0951832007000117
I’m not worried - I just bought another bulk pack of I-M 33" wheels - It’s hard to develop problems when they are sitting in the box(tore down the layout). It will be maybe next year before the new layout is up and running. I can only take so many at a time down to the club for ‘exercise’…
Jim
Be thankful that engineers do these sorts of fatigue testing on the prototype. Otherwise, it would lead to way more more horrendous wrecks. Our “minute” scale replicas don’t even come close to the stress experienced on real-life trains.
Tom
A little math to consider:
Strength of materials DOES NOT SCALE. Alloy X (or whatever, from cheddar cheese to armor plate) has a shear strength of Y kg/cm2 no matter whether it’s formed into a straight pin or a battleship’s propeller shaft.
Effective strength of materials (and model surface area/footprint) is the square root of S, S being the ratio of model to full scale size.
Mass of material is the cube root of S.
Effectively, our HO wheels are 87.1 times stronger then 1:1 scale wheels of the same material. That’s why we can get away with brass alloy or soft plastic while the prototype has to use forged, machined and heat treated alloy steel wheels. Of course, since I model in HOj, my wheels are only 80 times stronger…
Chuck (Modeling Central Japan in September, 1964)
If I tried applying this to HO wheels I think I would need to have my head examined.
Gentlemen,
I have erred in my attempt at humor, I was interested in the data as a “how cool is that”. Thought it would be appreciated for the reasons you have pointed out. Just letting you all know I am not thinking my HO wheels need to be fretted over like this. [#oops]
KG Not to worry I got a good laugh out of it.
What I find funny is they’re reseaching something the railroads already knows…That’s why railroads inspect freight car wheels and have a operation known as a wheel shop.
It is funny. But, rubber traction tires do deform with time.
Did you know that all matter moves, even those steel wheels while sitting still. LOL.
Richard
Richard,
I know this is going to stray from topic, but all matter moves though standing still is true.
So, How fast is a tank tread running when the tank is going 40 mph?
Answer: zero mph.
You’re right. But, one time when I was a lot younger working a summer job operating a D8–I almost got it stuck. Those tracks made twin rooster tails of about 20’ high–lol
Richard
Partially correct.
The upper portion of the tread is moving at 80 MPH. Other portions all have varying horizontal vectors, depending on their angle in relation to the ground. Vector addition yields 40 MPH relative to the (presumably level) road.
HOWEVER, now you have to add rotational speed (varies with latitude,) orbital speed (varies slightly since Earth’s orbit is elliptical,) orbital speed of the entire Solar System around the black hole at the center of the Galaxy…
Bet you never ever dreamed a tank could travel that fast!
(Back on topic) The same thing applies to railroad wheels.
Chuck (Modeling Central Japan in September, 1964 - Writing about the free-spacer culture of 3625)