Finding a Variable through iterating. This one is killing me! 1

[maloneb]

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.

 

[Occupant]

I've blown this thing up including a marker at zero around the region of interest. There really is only one solution of 5.5mm as indicated before.

 

[jghrist]

I think if you'll blow the thing up even more closer to zero, and include a little negative thickness, you'll see the other solutions. The workbook I attached to my post yesterday was your workbook with the new E and sigma values and using Minerr. Your graph showed the two sides of the equation separately and the way I blew it up, they definitely cross in three places.

 

[Spiry]

here is the change you have some mistake with the units of there