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7.16 A cylindrical specimen of some alloy 8 mm in diameter is stressed elastically

in tension. A force of 15,700 N produces a reduction in specimen diameter of 5 _ 10_3 mm. Compute Poisson’s ratio for this material if its modulus of elasticity is 140 GPa .

7.17 A cylindrical specimen of a hypothetical metal alloy is stressed in compression.

If its original and final diameters are 20.000 and 20.025 mm, respectively, and its final length is 74.96 mm, compute its original length if the deformation is totally elastic. The elastic and shear moduli for this alloy are 105 Gpa and 39.7 GPa, respectively.

7.19 A brass alloy is known to have a yield strength of 275 MPa, a tensile strength of

380 MPa, and an elastic modulus of 103 GPa . A cylindrical specimen of this alloy 12.7 mm in diameter and 250 mm long is stressed in tension and found to elongate 7.6 mm . On the basis of the information given, is it possible to

compute the magnitude of the load that is necessary to produce this change in length? If so, calculate the load. If not, explain why.

7.20 A cylindrical metal specimen 15.0mmin diameter and 150mm long is to be

subjected to a tensile stress of 50 Mpa; at this stress level the resulting deformation will be totally elastic.

(a) If the elongation must be less than 0.072mm,which of the metals in Tabla7.1 are suitable candidates? Why ?

(b) If, in addition, the maximum permissible diameter decrease is 2.3×10-3mm,which of the metals in Table 7.1may be used ? Why?

7.22 Cite the primary differences between elastic, anelastic, and plastic deformation

behaviors.

7.23 diameter of 10.0 mm is to be deformed using a tensile load of 27,500 N. It must

not experience either plastic deformation or a diameter reduction of more than

7.5×10-3 mm. Of the materials listed as follows, which are possible candidates? Justify your choice(s).

7.24 A cylindrical rod 380 mm long, having a diameter of 10.0 mm, is to be

subjected to a tensile load. If the rod is to experience neither plastic deformation