Calculation of shaft acc. to ASME BTH-1 3

[Nicolas03]

Currently, I'm calculating combined stress (bending + shear) of shaft for lifting beam based on ASME BTH-1-2017. However, according to the equation (4-10): Sc = √(S^2 + 3*T^2) ≤ Su/5, it results that Sc is too higher than Su/5 because the factor is = 5. While if I use von mises stress equation in EN1993-1-8 standard with safety factor = 2, it'll be ok. So, I'm thinking about solutions:
1. Increase diameter of shaft to satisfy equation (4-10) in ASME BTH-1-2017
2. Keep the current diameter of shaft and use nominal design factor = 2 as mentioned in section 3-1.3 in ASME BTH-1 to calculate the shaft.
3. As I knew, ASME B106.1-1985 is also used for transmission shafting and found that it use safety factor is 2. So, can I use this ASME B106.1-1985 or must follow shaft formula in ASME BTH-1.

Please advise me about this matter.

Thank you,

Nicolas

 

[NRP99]

ASME - ANSI B106.1M - Design of Transmission Shafting was used for shaft design earlier but is now withdrawn. But you can anyway use for reference purpose for 'transmission shafts' only.

ASME BTH and B106.1 are totally two different standards addressing totally different components.

For lifting component design, factor of 5 is normal. You need to increase the diameter if it's not sasfying the allowable stress criteria.
.

 

[MintJulep]

It's hard to imagine any single component that could simultaneously be:

1. In the load path of a Below the Hook lifting device and thus needing to comply with BTH-1

2. A power transmission shaft needing to comply with ASME B106.1

3. A structural joint subject to predominantly static loading that should be designed to EN 1993-1-8.

Perhaps you could draw us a sketch showing your whatever.

Engineering is not a buffet where you just take whatever looks good from different tables and hope that it all tastes good together.