Maximum stress as percentage of Yield Strength

[Shell343]

Homework Statement

Hi guys,

I have a question here, which asks me to express the maximum stress from my simply supported beam, which I worked out to be 1.165MPa, to be expressed as a percentage of the Yield strength 95MN/m^2.

I also have a follow on from that which asked me how much the cross-sectional wall thickness must be increased by so that the max stress is 40% of the yield strength.

Could someone else explain how to work this out to me please?

Homework Equations

The Attempt at a Solution

 

[PhanthomJay]

You will first have to show how you calculated the max stress. Your numbers show that max stress is only about 1% of yield stress, so wall thickness would decrease to get max stress of 40% yield. Please show your work.