Company wants to use a 100 m long steel cable to pull an airplane glider. If the glider has a mass of 1000 kg, and assuming the load is given by F=mg = 9800 N, and if the Young’s modulus of steel is 200 GPa (200,000,000,000 Pa), and Poisson’s ratio is 0.3:
a) If you want the stress on the wire to equal half the yield stress (yield stress is 200 MPa= 200,000,000 Pa), what is the diameter of the wire you would choose (assume the wire has a circular cross-section)?
b) What is the resulting strain of the wire when it is used?
c) What is the change in length?
d) How much does the diameter change?
e) In a few words, explain the deformation mechanism that primarily occurs at small elastic tensile strains.
f) What is the largest allowable size surface crack/notch/scratch on the cable? Assume the highest stress occurs during takeoff when the force is due to the weight of the plane (9800 N), assume Y=1, and K1c of this alloy is 60 Mpa – m0.5