Forums: Climbing Information: The Lab: Re: [brunoschull] Check my force calculator Excel spreadsheet: Edit Log




jt512


Mar 5, 2011, 12:03 PM

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Registered: Apr 11, 2001
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Re: [brunoschull] Check my force calculator Excel spreadsheet
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brunoschull wrote:
Hi,

First, I have posted lately about force calculation stuff. I have received overwhelmingly helpful feedback, and detailed explanatory comments. Thanks! I really appreciate that. There seems to be a great depth of experience and knowledge in this area on the site. Cool.

I made a Excel spreadsheet to make these calculations easy to play with. Of course, they are approximations, but it's still interesting to learn about the possible forces in climbing situations.

If would be great if somebody felt like checking the equations, or seeing of the numbers generated are reasonable. It's easy to make a mistake.

Some notes:

-I attached two versions, new (.xlsx) and old (.xls) Excel. Don't know if they will both work.

-The main fields you can change are the mass, the distance fallen and length of rope deployed, and the K value.

-The K value table and equations are there for reference.

-The different forces for climber, protection, and belayer were from my best understanding of how these forces are mathematically related.

Comments welcome, and please feel free to modify/use/change/discard as wanted.

Safe climbing,

Bruno

You have successfully programmed the standard equation for impact force.* Your results agree with mine to within rounding error.

If you want to test your results further, you can check them using my online impact force calculator. In my calculator, the first column of results uses rgold's equations, so your results should agree with those. To make the results comparable, set the "friction factor" in my calculator to 0.4, and make sure you enter the other numbers in the units indicated.

*That said, you could use a little help with Excel programming. Instead of typing that whole megillah in cell B10, you could have just typed B8*.6, and in B9 you could have just entered B7+B10. For your table of "K values," try this: Type rgold's equation for converting rope impact force rating to rope modulus in cell E3. Don't type in 7.00 for the rope impact force; instead type D3. Then copy and paste that equation, without changing anything, to cell range E4 to E9, and watch the magic!

Jay


(This post was edited by jt512 on Mar 5, 2011, 12:07 PM)



Edit Log:
Post edited by jt512 () on Mar 5, 2011, 12:06 PM
Post edited by jt512 () on Mar 5, 2011, 12:07 PM


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