Wheel loading for underhung crane as per CMAA 74 1

[bsmet95]

I'm in the engineering department of a crane manufacturer. CMAA 74 (2010) section 4.7.2 has spec's. for crane wheels. Table 4.7.2.3-1 gives allowable loads based on wheel dia., wheel tread type, etc., all based on wheel hardness of Brinell 200. A "simple formula" is mentioned on which the table is based, but the formula is not given. I have an application for 4" dia. wheels of copper alloy C86200, Brinell 180. I checked an old Whiting Crane Handbook but couldn't find any formula including wheel hardness. Can anyone direct me to a formula?

 

[dhengr]

Bsmet95:

It’s basically a Hertz bearing stress problem. Look in any good Advanced Strength of Materials or Theory of Elasticity text to get started. The bearing stresses are a function of the diameter, tread shape, Fy, and hardness of the wheel; and the same properties for the rail or beam flg. mat’l. Then there is also a whole bunch of history and experience factored in there too.