## Finding a Variable through iterating. This one is killing me!

## Finding a Variable through iterating. This one is killing me!

(OP)

Hey guys, I'm relatively new to mathcad and have hit a wall. All the data needed is attached to this message.

The formulae are lifted straight out of DNV-OS-F101 for the Local Buckling - Collapse of off shore Pipelines.

The Problem is that the data provided must be used to find a value of t_nom by setting the value of P_c = P_coll.

In Excel, the program runs with an estimated value of t_nom and iterates until the value of P_c > P_coll, therefore giving a suitable value of t_nom.

Is there any way of doing this in mathcad?

Thanks guys, I'm really stuck here.

The formulae are lifted straight out of DNV-OS-F101 for the Local Buckling - Collapse of off shore Pipelines.

The Problem is that the data provided must be used to find a value of t_nom by setting the value of P_c = P_coll.

In Excel, the program runs with an estimated value of t_nom and iterates until the value of P_c > P_coll, therefore giving a suitable value of t_nom.

Is there any way of doing this in mathcad?

Thanks guys, I'm really stuck here.

## RE: Finding a Variable through iterating. This one is killing me!

## RE: Finding a Variable through iterating. This one is killing me!

## RE: Finding a Variable through iterating. This one is killing me!

http://f

TTFN

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## RE: Finding a Variable through iterating. This one is killing me!

In the document you've presented, t_nom is still undefined earlier in the equation, and Find(t_nom) is also undefined, how do I solve this?

I really am a complete newbie with mathcad, I'm talking baby steps...

## RE: Finding a Variable through iterating. This one is killing me!

## RE: Finding a Variable through iterating. This one is killing me!

## RE: Finding a Variable through iterating. This one is killing me!

As a general rule, one should graph the expressions to see whether they behave as expected, and whether a solution is plausibly achievable. The equations, as written have graphical solution ~0.5183226, which seems absurdly small. There also is an anomalous D.0/t.nom expression, where all the other instances are t.nom/D.0. However, changing that one instance makes little difference to the problem as a whole.

http://f

TTFN

FAQ731-376: Eng-Tips.com Forum Policies

Chinese prisoner wins Nobel Peace Prize

## RE: Finding a Variable through iterating. This one is killing me!

## RE: Finding a Variable through iterating. This one is killing me!

TTFN

FAQ731-376: Eng-Tips.com Forum Policies

Chinese prisoner wins Nobel Peace Prize

## RE: Finding a Variable through iterating. This one is killing me!

TTFN

FAQ731-376: Eng-Tips.com Forum Policies

Chinese prisoner wins Nobel Peace Prize

## RE: Finding a Variable through iterating. This one is killing me!

## RE: Finding a Variable through iterating. This one is killing me!

TTFN

FAQ731-376: Eng-Tips.com Forum Policies

Chinese prisoner wins Nobel Peace Prize

## RE: Finding a Variable through iterating. This one is killing me!

## RE: Finding a Variable through iterating. This one is killing me!

## RE: Finding a Variable through iterating. This one is killing me!

5.16mm is extremely close to the desired answer, a hell of a lot closer than I had been getting.

Just to clarify, is Minerr a pre-built in function to Mathcad?

Thanks for all the help guys

## RE: Finding a Variable through iterating. This one is killing me!

## RE: Finding a Variable through iterating. This one is killing me!

Do you have the file you have used? Could you post it please?

## RE: Finding a Variable through iterating. This one is killing me!

## RE: Finding a Variable through iterating. This one is killing me!

## RE: Finding a Variable through iterating. This one is killing me!

## RE: Finding a Variable through iterating. This one is killing me!

## RE: Finding a Variable through iterating. This one is killing me!