(b)The 0.002 strain offset line is constructed as shown in the inset its intersection with the stress-strain curve is at approximately 250 MPa, which is the yield strength of the brass (c) The maximum load is calculated by using Equation 7. 1, in which is taken to be the tensile strength, from Figure 7.12, 450 MPa Solving for F, the maximum load, yields (450×105Nm3/12.8×103m1)m=57900N(1300b) d)in Equation 7. 2, it is first necessary to determine the strain that is produced by a stress of 345 MPa. This is accomplished by locating the stress point on the stress-strain curve, point A, and reading the corresponding strain which is approximately 0.06 △l=∈lo=(0.06)(250mm)=15mm(0.6in)
(b) The 0.002 strain offset line is constructed as shown in the inset; its intersection with the stress–strain curve is at approximately 250 MPa, which is the yield strength of the brass. (c) The maximum load is calculated by using Equation 7.1, in which is taken to be the tensile strength, from Figure 7.12, 450 MPa. Solving for F, the maximum load, yields (d) in Equation 7.2, it is first necessary to determine the strain that is produced by a stress of 345 MPa. This is accomplished by locating the stress point on the stress–strain curve, point A, and reading the corresponding strain which is approximately 0.06
EXAMPLE PROBLEM 7.3 From the tensile stress-strain behavior for the brass specimen shown in figure 7.12, determine the following (a)The modulus of elasticity. (b The yield strength at a strain offset of 0.002. (c)The maximum load that can be sustained by a cylindrical specimen having an original diameter of 12.8 mm(0.505 in (d)The change in length of a specimen originally 250 mm(10 in )long that is subjected to a tensile stress of 345 MPa (50,000 psi) SOLUtioN E= slope ∈∈ 2 E=150-0)MPa=938cPa 0.0016-0
500 70 Tensile strength 450MPa(65000psi) 60 400 40 300 MPa 200 Yield strength 200 250Ma(36000530 20 100 20 10 00 0 0.005 0 0.10 0.20 0.30 0.40 Stra FIGURE 7. 12 The stress-strain behavior for the brass specimen discussed in Example Problem 7.3
(b)The 0.002 strain offset line is constructed as shown in the inset; its intersec tion with the stress-strain curve is at approximately 250 MPa (36,000 psi) which is the yield strength of the brass (c) The maximum load that can be sustained by the specimen is calculated by using Equation 7.1, in which o is taken to be the tensile strength, from Figure 7.12, 450 MPa(65,000 psi). Solving for F, the maximum load, yields F=0A0 T (450×10Mm2/128×103m 丌=57,900N 2 △/=∈b=0.06)(250mm)=15mm0.6in)
(d)