Calculation of Residual strength of synthetic hawser rope 1

[jayakumaran]

I have calculated the hawser mooring rope’s residual strength (life prediction) and need confirmation on its accuracy. Please review my attached PDF. The OCIMF formula R=S−(S−A)(N/e^A(S−L))^B gave unrealistic results due to a very large exponent, so I used an alternative formula and took five example loads and cycles for the calculation in the pdf.

 

[Doug Hunter]

I recommend comparing your calculation results to known/trusted benchmarks. I'd be surprised if anyone here is going to check your calculations.

 

[3DDave]

Please stop asking the same question in multiple places here.

 

[TugboatEng]

What material? Is the rope wet or dry?

 

[jayakumaran]

I recommend comparing your calculation results to known/trusted benchmarks. I'd be surprised if anyone here is going to check your calculations.

ok thank you sir.

 

[jayakumaran]

Please stop asking the same question in multiple places here.

I apologize for that. Understood, sir.

 

[jayakumaran]

What material? Is the rope wet or dry?

My rope is made of HMPE and is used for offshore mooring operations, so it is typically wet due to marine conditions.

 

[GregLocock]

If I haven't misunderstood - Does it seem likely that in step 2 increasing load gives more cycles to failure? Not being a rope expert or anything...

 

[jayakumaran]

If I haven't misunderstood - Does it seem likely that in step 2 increasing load gives more cycles to failure? Not being a rope expert or anything...
View attachment 5168

That’s a great question. The number of cycles should actually decrease as the load increases. I followed the formula, but it seems to have led me in the wrong direction. I applied three formulas—Miner’s Rule, the cumulative damage hypothesis, and the S-N curve formula—but the specific calculation for the number of cycles to failure is not a standard one and was generated by ChatGPT.

If you have any alternative suggestions, I’d appreciate your insights. This predictive calculation is critical to ensuring the safety of the mooring line when the tanker is secured to the buoy.

Thanks for your valuable reply sir.

 

[LittleInch]

but the specific calculation for the number of cycles to failure is not a standard one and was generated by ChatGPT.

Oh dear.

Just goes to show that the I bit in AI doesn't really stand for Intelligence....

 

[GregLocock]

Having recently been led astray by 2 different AI chatbots (on the same problem) I have some sympathy. But only some.

 

[jayakumaran]

I understand, AI can be a bit unpredictable sometimes. Thank you for your patience LittleInch and GregLocock. I’ll ensure I provide correct information moving forward.