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Problem 5 [20%] The fatigue crack growth (FCG) behavior of additive manufactured (selective laser melting) 316L stainless steel is given in the figure below. The plane strain fracture toughness of the as- built samples is $K_{Ic} = 90 ext{ MPa } m^{1/2}$ (1) Mark in the figure the stages of FCG. Explain the significance of each stage. (2) An as-fabricated mechanical component by selective laser melting contains an initial edge crack with length $a = 0.2 ext{ mm}$. If the component is subjected to cyclic loading, where $R=0.1$ and $sigma_{max} =$ 500 MPa. What is the fatigue life of the component? (3) What should the maximum/minimum stresses ($sigma_{max}$ and $sigma_{min}$) be to ensure that the $Delta K$ is below the threshold stress intensity factor range ($Delta K_{th}$)?

          Problem 5 [20%] The fatigue crack growth (FCG) behavior of additive manufactured (selective laser
melting) 316L stainless steel is given in the figure below. The plane strain fracture toughness of the as-
built samples is $K_{Ic} = 90 	ext{ MPa } m^{1/2}$
(1) Mark in the figure the stages of FCG. Explain the significance of each stage.
(2) An as-fabricated mechanical component by selective laser melting contains an initial edge crack
with length $a = 0.2 	ext{ mm}$. If the component is subjected to cyclic loading, where $R=0.1$ and $sigma_{max} =$
500 MPa. What is the fatigue life of the component?
(3) What should the maximum/minimum stresses ($sigma_{max}$ and $sigma_{min}$) be to ensure that the $Delta K$ is below the
threshold stress intensity factor range ($Delta K_{th}$)?

$Problem 5 [20%] The fatigue crack growth (FCG) behavior of additive manufactured (selective laser melting) 316L stainless steel is given in the figure below. The plane strain fracture toughness of the as- built samples is KIc = 90 ext MPa m^1/2 (1) Mark in the figure the stages of FCG. Explain the significance of each stage. (2) An as-fabricated mechanical component by selective laser melting contains an initial edge crack with length a = 0.2 ext mm. If the component is subjected to cyclic loading, where R=0.1 and sigmamax = 500 MPa. What is the fatigue life of the component? (3) What should the maximum/minimum stresses (sigmamax and sigmamin) be to ensure that the Delta K is below the threshold stress intensity factor range (Delta Kth)?$

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