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# ISO20332 guidance

## ISO20332 guidance

(OP)
I'm seeking guidance on ISO20332, Specifically, parts relating to fatigue assessment. The parameter 'm' is related to the relationship between stress and load cycles. Clause 6.2.3 permits using m=3 for a simplified assessment, however, most of the example cases in Table D.1 are for m=5. It seems that m=5 is the more conservative approach, but it's too conservative in my case. What is the intended workflow for selecting and applying the value of 'm'?

EDIT: Furthermore, the formula: ΔσRd = Δσc/ (γmf x (sm)^(1/m)) (eq 39) yields a value HIGHER than the material yield stress for many (most?) value combinations (e.g. Δσc=160, γmf = 1.25, m=3 or 5, sm=0.032. Which doesn't makes sense in the case of non-reversing loads.

### RE: ISO20332 guidance

What is the application?
What is the material?
What are the regulatory requirements?

### RE: ISO20332 guidance

(OP)
I'm not quite sure how to answer that one. ISO20332 is fairly specific, so it's somewhat self-explanatory. In any case, the application is a crane application (in my case, a static winch), the material is mild carbon steel, and the regulatory requirement is to comply with ISO20332.

I hope that helps clarify my enquiry.

### RE: ISO20332 guidance

Ok, thanks. I’m not familiar with that ISO and am not going to purchase it.

Seems like selection of m would depend on the criticality / redundancy of the part and consequences of failure. Also would depend on whether there are other conservatisms in the fatigue loads calculation.

### RE: ISO20332 guidance

(OP)
Hi, thanks for taking the time to respond, but without a knowledge of the specific standard, any answer is a guess and isn't helpful.

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