Question

A specimen of 4340 Steel Tempered at 425 C is being tested using a single edge notched tension configuration. The estimated Y parameter for the SENT is 2.5. If the specimen is loaded to 60% of the yield strength, what length of starter crack (inches) will cause the specimen to fail by fracture

Answer 1

Answer:

length of starter crack = 1.056

Explanation:

given data

temperature = 425 C

yield strength = 60%

Y parameter = 2.5

solution  

we use here A 20 table so we get here value that is

Sy = 1360 MPa

Kic = 117.5 MPa $\sqrt{m}$

so length of starter crack  will be

a = $\frac{1}{\pi } (\frac{Kic}{Y\times \sigma max})^2$     .....................1

put here value and we will get

a =  $\frac{1}{\pi } (\frac{117.5}{2.5\times 0.6 \times 1360})^2$  

solve it we get

length of starter crack = 1.056