The image above represents Goodman’s law.
To compute for goodman’s law, three essential parameters are needed and these parameters are Fatique Limit (τe), New Fatique Limit (τm) and Tensile Strength of Alloy of Spring (TS).
The formula for calculating Goodman’s law:
τ = τe(1 – τm/0.67TS)
Where:
τ = Goodman’s Law (τ)
τe = Fatique Limit
τm = New Fatique Limit
TS = Tensile Strength of Alloy of Spring
Let’s solve an example;
Find the goodman’s law when the fatique limit is 4, the new fatique limit is 10 and the tensile strength of alloy of spring is 12.
This implies that;
τe = Fatique Limit = 4
τm = New Fatique Limit = 10
TS = Tensile Strength of Alloy of Spring = 12
τ = τe(1 – τm/0.67TS)
τ = 4(1 – 10/0.67(12))
τ = 4(1 – 10/8.040)
τ = 4(1 – 1.24)
τ = 4(-0.24)
τ = -0.975
Therefore, the goodman’s law is -0.975.