P 6 In tensile test of steel, the following data obtained Lord (KN): 0 min. dia. (mm): 12.8 103 121 81.8 8.94 Determine (a)- The material constant (K) according to the behavior KÈn. (b)- what are the max. Stress in the weaked cross-section? @

3) An bronze rod is rigidly attached between a aluminum rod and a steel rod as shown. Axial loads are applied at the positions indicated. Find the maximum allowable value of P that will not exceed a stress in steel of 140MPA, in aluminum of 90MPA or in bronze of 100MPа. Aluminum A = 500mm? Bronze A = 200mm? Steel A = 150mm2 2P ЗР L st = 1.2m L br = 2m Lal = 3.5m

1.4-7 The data shown in the table below were obtained from a tensile test of high-strength steel. The test specimen had a diameter of 13 mm and a gage length of 50 mm (see figure for Prob. 1.4-3). At fracture, the elongation between the gage marks was 3.0 mm and the minimum diameter was 10.7 mm. Plot the conventional stress-strain curve for the steefor the steel and determine the proportional limit, modulus of elastics of elastic- ity (i.e., the slope of the initial part of the stress-strain,tress-strain curve), yield stress at 0.1% offset, ultimate stress, percent, elongation in 50 mm, and percent reduction in area. 'ess, percent area. TENSILE-TEST DATA FOR PROB. 1.4-7 Elongation (mm) 0.005 0.015 0.048 Load (kN) 5 10 30 50 0.084 60 0.099 64.5 0.109 67.0 0.119 68.0 0.137 69.0 0.160 70.0 0.229 72.0 0.259 76.0 0.330 84.0 0.584 92.0 0.853 100.0 1.288 112.0 2.814 113.0 Fracture

The state of plane stress shown occurs at a critical point of a steel machine component. As a result of several tensile tests, it has been found that the tensile yield strength is o, = 250 MPa for the grade of steel used. Determine the factor of safety with respect to yield using (a) the maximum shearing stress criterion, and (b) the maximum distortion energy criterion. ↑y 40 40 MPa 80 MPa 25 MPa ➜X