Problem 1 Ou Experimental values for the properties of an alloy steel are: (See problem 8-14 worked out in class) = 215,

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Problem 1 Ou Experimental Values For The Properties Of An Alloy Steel Are See Problem 8 14 Worked Out In Class 215 1 (98.81 KiB) Viewed 33 times

Problem 1 Ou Experimental values for the properties of an alloy steel are: (See problem 8-14 worked out in class) = 215,000 psi Oyp = 200,000 psi k = 323,751 psi n' = 0.15 & 0.48 OF 290,000 psi b -0.091 -0.60 с A direct tension member made of this alloy has a single semicircular notch that results in a fatigue stress concentration factor of 1.6. The net cross sectional area at the root of the notch is 0.35 x1.43 =0.5 in?, and hence nominal stress is equal to S=P/0.5 = 2P. Find the Strain amplitude (Aɛ/2) and number of cycles to initiate a crack at the root notch (Ne) for the following loading conditions (use of MATLAB, Excel, Mathcad or other program recommended): A completely reversed nominal cyclic tensile load of P=97,500 lbf, that gradually reduces to 4,500 lbf, in steps of 2500 lbf. Present the following: a. For each load print out Aɛ/2, Aɛe/2, A£p/2, Nf and Sa. b. Plot Aɛ/2 and Sa Vs. 2Nf, on a log-log scale. c. Plot (log-log) the elastic and plastic portions of the strain Vs. 2N: (Strain-Life Curve). d. Plot (Aɛ/2) vs. (25/2). This is the cyclic stress-strain curve.