# Failure criteria to predict failure in design components

Q.  To predict failure in design components which failure criteria is not assumed, when mean stress and stress amplitude are nonzero?
- Published on 14 Sep 15

a. Goodman criterion
b. Soderberg criteria
c. Gerber criteria
d. None of the above

#### Discussion

• Sravanthi   -Posted on 03 Nov 15
- Failure in design components can be predicted by assuming Goodman criteria, Soderberg criteria and Gerber criteria, when mean stress and stress amplitude are nonzero.

- Line joining Se on stress amplitude axis and Sut on mean stress axis is known as Goodman line. The equation for Goodman line is (σm / Sut) + (σa / Se) = 1 / Nf

- Line joining Syt (yield strength of the material) on mean stress axis and Se (endurance limit of the component) on stress amplitude axis is called as Soderberg line. The equation for Soderberg line is (σm / Syt) + (σa / Se) = 1 / Nf

- Se on stress amplitude axis and Sut on mean stress axis is joined by a parabolic curve according to Gerber criteria. The equation for Gerber line is (Sm / Sut) + (Sa / Se) = 1 / Nf

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