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Unformatted text preview: Home Introduction Policies Resources Requirements & Grading Syllabus Assignments Handouts Discussion Web Links Distance Learners Contact MSE 200 Test 2 Equations: σ =F/Ao, σ =F/A, σ / ε =E, KI= σ f ( [π c) 1/2 , ε '= ε o exp(Q/kT), RSS= σ a cos φ cos λ σ y= σ o+K/d 1/2 , BHN=2P/ [π D{D(D 2d 2 ) 1/2 }] A.B=A B cos θ Q1. A landing gear must be capable of supporting onethird of an airplane that weighs 200 tons (1 ton=2000 pounds). Just to be safe, we wish that the landing gear to be able to support twice the maximum load. Determine the minimum crosssectional area of the landing gear if it is made of heat treated steel having a yield strength of 125 ksi and a tensile strength of 132.5 ksi. Answer the following questions, and each carries 2 points. 1. Weight in tons that the landing gear should support including the factor of safety is a. 200 b. 133.33 c. 66.66 (b ) 2. The landing gear is subjected to a. tension b. compression c. shear (b ) 3. Stress in the landing gear should not exceed a. 125 ksi b. 132.5 ksi c. 62.5 (a ) 4. Stress in ksi in the landing gear with crosssectional area A in sq.inch is a. 400/A b. 266.66/A c. 266.66 (A) (b ) 5. Area of crosssection A in square inches of the landing gear should be a. 2.13 b. 2.01 c. 0.50 (a ) Q2. We would like to produce by rolling a copper plate of final thickness 0.25 inches when it is removed from the rolls. Assume the plastic deformation to be very small. The yield strength of copper is 35 ksi and tensile strength is 55 ksi. The modulus of elasticity is 18 Mpsi. Calculate the separation between the rolls that we should use, assuming that the surface of the rolls are very stiff and do not relax. Answer the following questions and each carries 2 points. 1. Copper plate when rolled in the rolls undergoes a. elastic tensile deformation b. plastic compressive deformation c. elastic and plastic compressive deformation (b ) Note when rolling is complete, elastic deformation is recovered and only plastic deformation remains. 2. After rolling, the change in the dimensions of the copper plate arise from a. elastic deformation b.plastic deformation c. elastic and plastic deformation ( a) 3. To calculate the strain in the plate after it is removed, we should use the stress value of a. yield strength b. modulus of elasticity c. tensile strength (a ) 4. Upon removal from the rolls, the dimension (thickness) of the copper plate a. increases b. decreases c. does not change (a ) 5. Strain in the copper plate after removal from the rolls if the separation between the rolls is t can be written as a. (t0.25)/t b. (0.25t)/0.25 c. t/0.25 (a ) 6. Magnitude of stress in Mpsi the copper plate for the above strain is a. 18(t0.25)/t b. (t0.25)/18t c. 35(0.25t)/t (a )a....
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This note was uploaded on 10/11/2009 for the course MSE 200 taught by Professor Wholedepartment during the Spring '08 term at N.C. State.
 Spring '08
 wholedepartment

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