# Bending stress + bending moment

## Homework Statement

A steel strip of breadth 50 mm and depth 3 mm needs to be bent around a drum of diameter 4 m. What bending moment is required and what will be the maximum stress produced? The modulus of elasticity of the steel is 210 GPa

## Homework Equations

$$\frac{M}{I} = \frac{\sigma _b}{y} = \frac{E}{R}$$

## The Attempt at a Solution

I'm able to find the bending moment by finding the second moment of area...

1.05 x1011 x 1.125 x10-10 = 11.8 Nm

however i'm stuck on how to then go on and find the maximum stress

PhanthomJay
Science Advisor
Homework Helper
Gold Member

## Homework Statement

A steel strip of breadth 50 mm and depth 3 mm needs to be bent around a drum of diameter 4 m. What bending moment is required and what will be the maximum stress produced? The modulus of elasticity of the steel is 210 GPa

## Homework Equations

$$\frac{M}{I} = \frac{\sigma _b}{y} = \frac{E}{R}$$

## The Attempt at a Solution

I'm able to find the bending moment by finding the second moment of area...

1.05 x1011 x 1.125 x10-10 = 11.8 Nm

however i'm stuck on how to then go on and find the maximum stress
You have already noted the formula that bending stress = My/I.......you just need to identify the value for 'y' where the bending stress is at its maximum.