You have been given the S-N plot below for a test material: What is the Fatigue Limit for this test material and what would be its Fatigue Life at a stress of 130 MPa? (This question has only one correct answer) 450 400 350 300 250 200 150 100 50 104 105 106 107 10 10° Stress Amplitude (MPa)

1. For the stress-strain curve shown below, please estimate the properties indicated. (a) Fracture Strain Please do your work on a separate sheet of paper, and put your answers in the boxes on the right. Be sure to include the proper symbol and units. Stress Strain 70 60 50 Stress (ksi) 240 30 20 10 70 0 0.000 60 50 Stress (ksi) 40 20 10 KULL 0 0.000 0.010 0.050 0.100 Strain (in/in) Stress Strain 0.020 0.030 Strain (in/in) 0.040 0.150 0.050 (b) Ultimate Tensile Stress (c) Fracture Stress (d) Proportional Limit (e) Elastic Modulus (1) Yield Stress (g) Tensile Toughness (Modulus of Toughness) (h) Modulus of Resilience

You have been given the following test sample data following mechanical testing of 15 test pieces of Silicon Nitride. What is the Weibull modulus of this material? Would you advise the use of a similar material with a Weibull Modulus of 16.3 and a mean failure stress of 485 MPa, if you anticipate that the peak stress on the material could be 430 MPa? Sample 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Select one or more: O a. No O b. 18.6 O C. 13.4 O d. Yes O e. 15.7 f. 17.1 Failure Stress (MPa) 423 459 496 432 447 467 473 499 485 479 505 530 526 490 510 <

The creep data have been taken on an ahuminum alloy at 400°C and constant stress of 25MPA are shown in below Table, Find the steady state or minimum creep rate. Time (min) strain Time (min) 16 strain 0.135 0.0 0.0 2 0.025 18 0.153 4 0.043 0.065 20 0.172 0.193 0.218 22 0.078 24 10 0.092 26 0.255 12 0.109 28 0.307 14 0.120 30 0.368

Question 2 Figure 2 shows the dependence of fatigue strength on testing cycles (S-N curve) of an acetal polymer. 60 50 40 30 20 10 104 105 106 107 108 Number of cycles to failure Figure 2 The S-N fatigue curve for an acetal polymer a. What is the fatigue strength, or maximum stress amplitude, at one million cycles of loading? b. An acetal polymer 30-cm-long bar with a diameter of 20 mm is designed to survive one million cycles of loading, what is the maximum allowable axial load that can be applied on one end of the bar? Magnitude of stress Reversal, MPa

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A cylindrical steel bar 8 mm in diameter is loaded 1000 cycles per day with a load of 15560 N.  How long until fatigue failure takes place?  Note: stress = force/area   Group of answer choices The bar should not fatigue. The bar will fail in one cycle. 100 days 1000 days