Question

Please answer all 7 parts

lExaminatio The following information applies to questions 1 to 7 -below. You have a circular aluminum bar: 1 in diameter and 10" long. It is Type 2024-14 aluminum. It has the following properties: Tensile strength of: Yield Strength of: Modulus Of Elasticity of: Density of about: Coefficient of Thermal Expansion of: 12.9x10* in./in./ 68,000 #/square inch 47,000 #/square inch 10,600,000 #/square inch 0.1 lb/cubic inch 1) What are the 5 types of stress that you can subject the above bar to ? a) c) d) e) 2) For the above bar: if you load it in tension to 40,000# how much (inches) will it stretch? 3) If you increase its temprature by 100°F, will it shrink or grow in length ? 4) By how much ? (inches) 5) If you put a 5000 # load on it in the following manner, what kind of stresses are at points A, B and C? 5000 # LC C) 6) How much does it weigh ? (pounds) 7) A traditional tensile tester can perform all of the following mechanical property tests except: a. Hardness b. Shear strength C. Impact strength d. Bending modulus e. Yield strength f. Compressive yield strength Page 8 of 8

Answer 1

(1) (a) The bar can be subjected to normal stress due to normal force as shown below Compressive/ Normal stress = P/A {A = Area of cross - section (c) Bending tensile and (c) bending compressive stresses (c) shear stress rightarrow due to forsion (2) change in length, delta L = PL/AE delta L = (40, 000) times (10)/(pi/4 times 1)^2 times (10600000) = 0.048 inches (3) Increasing temperature mereases length because due to it the molecules try to slide and move away and hence expand the material. So it grows in length (4) change in length, delta L = L proportional T. = delta L = (10) times (12.9 times 10^-4) times (100) - = 1.29 in (5) when load 5000# is put it is case (c) in (1) as shown above, the upper sinres above centre and to compressive, so they are subjected of compressive stress and below centre that is c is subjected to tensile stress because it