- #1

- 12

- 0

## Homework Statement

A steel pipe is 200mm internal diameter and 20mm thick. Calculate the safe internal pressure if the allowable stress is not to exceed 140Mpa.

## Homework Equations

σr = A-B/r^2[/B]

and

**σtheta = A+B/r^2**

## The Attempt at a Solution

**Right so, I've got two equations.....**

(eq1)140MPa =A+B/0.1^2

and

(eq2)0 = A-B/0.12^2

(eq1)140MPa =A+B/0.1^2

and

(eq2)0 = A-B/0.12^2

**I need help getting A and B. Answers (A=57.38)and (B=0.826)**

I know I need to use simultaneous equations. Could someone please give me a step by step solution as I'm stuck.

I have so far done -(eq2)+(eq1) to cancel out A.

and got

...140MPa = B/0.1^2 + B/0.12^2

I'm not sure what to do next to get B.