sol-as2-f09

# sol-as2-f09 - SOLUTION TO HOMEWORK NO. 2 Fall 2009 1. (8...

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SOLUTION TO HOMEWORK NO. 2 Fall 2009 1. (8 pts each. -2 pts for not showing units or wrong units. -4 pts for not showing work.) 0 2 4 6 8 10 12 14 16 18 20 STRAIN (10 -3 ) 50 40 30 20 10 0 STRESS (KSI) JAEL O y 39 38 37 (A) E = 30 ksi / 4 X 10 -3 = 7.5 X 10 3 ksi (B) JAEL = 30 ksi (C) Yield strength at 0.2% offset = 37.5 ksi (D) Modulus of resilience = 30 ksi (4 X 10 -3 ) / 2 = 60 X 10 -3 ksi = 60 psi (E) Using the unit of psi, area under the stress-strain plot up to failure can be calculated as: Modulus of toughness = 60 + (30 + 37)/2 X 2 + (37 + 38)/2 X 2 + (38 + 39)/2 X 10 = 587 psi 1 2. (A) From the S-N diagram, the cyclic stress for 100,000 cycles is 220 MPa. (5 pts.) (a) Soderberg: (b) Goodman: (320 – X) / 140 = 320 / 220 (360 – X ) / 140 = 360 / 220 (320 – X ) = 203 360 – X = 229 X = 116 MPa (5pts.) X = 131 MPa (5pts.) (5 pts. for showing the correct plots.) Cyclic Stress (MPa) 100 220 320 360 Steady Stress (MPa) Goodman Soderberg 140 X X = additional steady stress on top of the cyclic stress to cause failure.

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2. (B) From the SN diagram, the numbers of cycles to failure for the three stress levels are:
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## This note was uploaded on 08/03/2011 for the course CGN 3501 taught by Professor Mang during the Spring '10 term at University of Florida.

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sol-as2-f09 - SOLUTION TO HOMEWORK NO. 2 Fall 2009 1. (8...

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