# Anybody help with these questions?

1. Sep 15, 2010

### scw1

Anybody help with these questions???

1. The problem statement, all variables and given/known data

A spherical pressure vessel has been designed such that the tensile stresses in its walls should not exceed 150MPa. The ratio of the vessels radius to wall thickness is 100. Applying a thin-walled plane stress assumption, what is the maximum uniform internal pressure that the vessel is intended to contain???

2. Relevant equations

Thin walled pressure cylinder assumption P= sigma(s) x radius/2xt(s)

3. The attempt at a solution
i tried the answer 0.15MPa but not sure if its right can anyone help me??

2. Sep 15, 2010

### rock.freak667

Re: Anybody help with these questions???

3. Sep 16, 2010

### scw1

Re: Anybody help with these questions???

Hi how do you denote the radius to wall thickness, is it 100 to 1 or 10 to 0.1???
Many thanks
Stevo

4. Sep 16, 2010

### rock.freak667

Re: Anybody help with these questions???

since r is the radius and t is the wall thickness

radius to wall ratio = 100 OR r/t = 100.

5. Sep 16, 2010

### nvn

Good advice by rock.freak667, except the equation should be sigma = p*r/(2*t).

6. Sep 17, 2010

### rock.freak667

Re: Anybody help with these questions???

Yes it should, I was thinking about a thin-walled cylinder.