Respuesta :
Answer:
a)σ₁ = 265.2 MPa
b)σ₂ = -172.8 MPa
c)[tex]Stress\ ratio =-0.65[/tex]
d)Range = 438 MPa
Explanation:
Given that
Mean stress ,σm= 46.2 MPa
Stress amplitude ,σa= 219 MPa
Lets take
Maximum stress level = σ₁
Minimum stress level =σ₂
The mean stress given as
[tex]\sigma_m=\dfrac{\sigma_1+\sigma_2}{2}[/tex]
[tex]2\sigma_m={\sigma_1+\sigma_2}[/tex]
2 x 46.2 = σ₁ + σ₂
σ₁ + σ₂ = 92.4 MPa --------1
The amplitude stress given as
[tex]\sigma_a=\dfrac{\sigma_1-\sigma_2}{2}[/tex]
[tex]2\sigma_a={\sigma_1-\sigma_2}[/tex]
2 x 219 = σ₁ - σ₂
σ₁ - σ₂ = 438 MPa --------2
By adding the above equation
2 σ₁ = 530.4
σ₁ = 265.2 MPa
-σ₂ = 438 -265.2 MPa
σ₂ = -172.8 MPa
Stress ratio
[tex]Stress\ ratio =\dfrac{\sigma_{min}}{\sigma_{max}}[/tex]
[tex]Stress\ ratio =\dfrac{-172.8}{265.2}[/tex]
[tex]Stress\ ratio =-0.65[/tex]
Range = 265.2 MPa - ( -172.8 MPa)
Range = 438 MPa
