The maximum measured Young’s modulus for a carbon nanotube is 950 GPa.  How much stress would have to be applied to this nanotube to have the same strain as in the steel sample?

A 5-mm-thick rectangular alloy bar is subjected to ajtensile load P by pins at A and B, as shown in the figure. The width of the bar is w = 33 mm. Strain gages bonded to the specimen measure the following strains in the longitudinal (x) and transverse (y) directions: €, =710 με and ε,--255 με (a) Determine Poisson's ratio for this specimen. (b) If the measured strains were produced by an axial load of P = 24 kN, what is the modulus of elasticity for this specimen? Answers: (a) v= (b) E= GPa

A tensile stress is to be applied along the long axis of a cylindrical nickel rod that has a diameter of 11 mm. Determine the magnitude of the load required to produce 2.5 × 10−3mm change in diameter if the deformation is entirely elastic.

Given your understanding of what initiates and controls failure in materials, which of the following will increase the failure strength or lifetime of a test piece or component and why? a. Decreasing the difference between the maximum and minimum stress values, as this effects the stress concentration factor b. Decreasing the temperature below the brittle-ductile transition temperature, to make it harder C. Polishing to reduce surface defects Od. Increasing its volume, to give a larger cross sectional area Oe. Increasing the grain size so there are less grain boundaries to initiate failure