Question

Problems 14, 15 & 16 A truss composed of 2 inch diameter bronze rods is subjected to the loading shown. 2 in. B y bronze = 50 ksi Efronxe = 15,000 ksi A 3 ft. A 4 ft. Problem 14 Determine the load P that will result in initial yielding of any of the three members. a) 307 kips b) 40r kips c) 50 kips d) 1207 kips e) 200x kips Problem 15 If P= 8 kips determine the strain in member AC. a) 0.00017 in/in b) 0.000042 in/in c) 0.000212 in/in d) 0 e) None of the above Problem 16 If P= 40 kips determine the length of AB under loading. a) 60.051 in b) 59.049 in. c) 60.064 in d) 60.038 in. e) 60.000 in

Answer 1

Grield 50 ksi Force (Yiela) Yielding force from 67 Force exield) = 50 For Member AB 7 FAB = 1.25P 500 = 1.25P P = 407 for AB member For Member Вс 50T = 0.75 P P C 66.6667 T for Bc member Select lesser value Q.14 Answer P = 40 1 kips option by

Page Q. 157 Strain, EAC = stress strain Strain Stress E FAC/ Area E Ans. :- 12 option d Zero TO AB : Under Tension Q. 167 .. Elongation Final length = original + EL length LE - Lo + OL Lo = 5 Ft 5X12 60 in strain - change in length, oh ܘܬ = = (5x12) X X FAB E cls Area

Answer - option dL = 60 x 1 15000 2 X 1.25x40 T (2) 2 4 dh 0.064 in LE Go to.064 IE = 60.064 in С