# Question: Among the decisions a designer must make is selection

Among the decisions a designer must make is selection of the failure criteria that is applicable to the material and its static loading. A 1020 hot-rolled steel has the following properties: Sy = 42 kpsi, Sut = 66.2 kpsi, and true strain at fracture εf = 0.90. Plot the failure locus and, for the static stress states at the critical locations listed below, plot the load line and estimate the factor of safety analytically and graphically.

(a) σx = 9 kpsi, σy = −5 kpsi.

(b) σx = 12 kpsi, τx y = 3 kpsi ccw.

(c) σx = −4 kpsi, σy = −9 kpsi, τx y = 5 kpsi cw.

(d) σx = 11 kpsi, σy = 4 kpsi, τx y = 1 kpsi cw.

(a) σx = 9 kpsi, σy = −5 kpsi.

(b) σx = 12 kpsi, τx y = 3 kpsi ccw.

(c) σx = −4 kpsi, σy = −9 kpsi, τx y = 5 kpsi cw.

(d) σx = 11 kpsi, σy = 4 kpsi, τx y = 1 kpsi cw.

## Answer to relevant Questions

A 4142 steel Q&T at 80◦F exhibits Syt = 235 kpsi, Syc = 275 kpsi, and εf = 0.06. Choose and plot the failure locus and, for the static stresses at the critical locations, which are 10 times those in Prob. 5–9, ...The network shown is a current-to-voltage converter or transresistance amplifier. Find VO/is for this network. Find the current Ix in the 4-ohm resistor in the circuit shown. This problem illustrates that the strength of a machine part can sometimes be measured in units other than those of force or moment. For example, the maximum speed that a flywheel can reach without yielding or fracturing is ...Repeat Prob. 5–27 using maximum shear stressPost your question