Question

A 225 MPa conducted in which the mean stress was 50 MPa and the stress amplitude was (a) Compute the maximum and (b) Compute the stress ratio. (c) Compute the magnitude of the stress range. minimum stress levels.

Answer 1

Answer:

Explanation:

Given data in question

mean stress  = 50 MPa

amplitude stress  = 225 MPa

to find out

maximum stress, stress ratio, magnitude of the stress range.

solution

we will find first  maximum stress  and minimum stress

and stress will be sum of (maximum +minimum stress) / 2

so for stress 50 MPa and 225 MPa

$\sigma _{m}$ =  $\sigma _{maximum}$ + $\sigma _{minimum}$  / 2

50 =  $\sigma _{maximum}$ + $\sigma _{minimum}$  / 2    ...........1

and

225 =  $\sigma _{maximum}$ + $\sigma _{minimum}$  / 2      ...........2

from eqution 1 and 2 we get maximum and minimum stress

$\sigma _{maximum}$ = 275 MPa        ............3

and $\sigma _{minimum}$ = -175 MPa     ............4

In 2nd part we stress ratio is will compute by ratio of equation 3 and 4

we get ratio =  $\sigma _{minimum}$ / $\sigma _{maximum}$

ratio = -175 / 227

ratio = -0.64

now in 3rd part magnitude will calculate by subtracting maximum stress - minimum stress i.e.

magnitude = $\sigma _{maximum}$ - $\sigma _{minimum}$  

magnitude = 275 - (-175) = 450 MPa