O The following engineering stress-strain data were obtained for a 0.2% C plain-carbon steel. (i) Plot the engineering stress-strain curve. (ii) Determine the ultimate tensile strength of the alloy. (iii) Determine the percent elongation at fracture. Engineering Engineering Engineering Engineering Stress Strain Stress Strain (ksi) (in./in.) (ksi) (in./in.) 76 0.08 30 0.001 75 0.10 55 0.002 73 0.12 60 0.005 69 0.14 68 72 0.010 65 0.16 0.020 56 0.18 74 0.040 51 0.19 75 0.060 (Fracture)

An aircraft component is fabricated from an aluminum alloy that has a plane strain fracture toughness of 31 MPa/m. It has been determined that fracture results at a stress of 227 MPa when the maximum (or critical) internal crack length is 2.47 mm. a) Determine the value of Yo√a for this same component and alloy at a stress level of 340 MPa when the maximum internal crack length is 1.24 mm. i MPa √//m b) Under these circumstances will the component fail? No Yes Unable to Determine 3

Q1. (i) Initial strain Please enter your supplied question data Q1. (ii) Eo B (hr¹Pa-¹) n IVICUITO Fracture 0.003 Please enter your answers here Your Q1. (i) Answers: 4.60E-34 Q1. (ii) 3.2 Q2. o (Pa) σo (Pa) 780,000,000 Q3. t (hr) Q2. A component is made from a metal that is known to be viscoelastic and behaves according to a secondary creep rate equation with constants of B and n provided as your input values. If the component is subjected to a constant force that results in the initial strain of E provided to you, determine the design stress for a secondary creep life of 1,000 hrs before attaining a limiting strain, &, of 0.01. Q3. If the same component is subjected to a constant displacement that results in the value of initial stress, o, provided to you, calculate the time for the stress to reduce to 200MPa. Young's modulus of the bolt is E = 200GPa.

Question 5: Following is tabulated data that were gathered from a series of Charpy impact tests on a tempered 4140 steel alloy. Temperature (°C) 100 75 50 25 0 -25 -50 -65 -75 -85 -100 -125 -150 -175 Impact Energy (J) 89.3 88.6 87.6 85.4 82.9 78.9 73.1 66.0 59.3 47.9 34.3 29.3 27.1 25.0 (a) Plot the data as impact energy versus temperature. (you can use Excel or other software). (b) Determine a ductile-to-brittle transition temperature as that temperature corresponding to the average of the maximum and minimum impact energies. (c) Determine a ductile-to-brittle transition temperature as that temperature at which the impact energy is 70 J.