Paper Graphic for Goodman

A steel tensile link, with a machined finish, and considered a "precision member", has the following properties: S, = 140 ksi, and S, = 110 ksi. The axial load "T" fluctuates between 1,000 lb and 7,000 lb, at a temperature of 805 F. A safety factor (S.F.) of 3 is specified. A. Roughly sketch a graph of load vs time, with time on the horizontal axis. Assume that the load varies from 1,000 lb to 7,000 Ib as a sine wave. Calculate the mean load and the alternating load from the max and min load values. Show the mean load on the sketch with a dashed line on the graph. Indicate with an arrow the alternating stress on the graph. B. Calculate the peak alternating stress S, at 10 cycles and the endurance limit S, at 10 cycles. Assume a reliability of 95%. C. Roughly sketch the S-N fatigue diagram as it would appear in log-log paper. Specify the peak alternating stress S, at 10 cycles and the endurance limit S, at 10 cycles. Extend the diagram to at least 10' cycles in your sketch. Clearly specify the title of both the horizontal and vertical axes. Indicate the values used in both axes. D. Determine the fatigue stress concentration factor K, for this case. To find K,, assume D/d = 1.05, and r/d = 0.10. Assume a notch radius r = 0.02 in to find the notch sensitivity factor, q. %3D E. Calculate the alternating stress og and the mean stresses om- For a uniaxial load, by definition: o = Then, establish the ratio of m = which will give you the slope of the "load line" that you Om will plot in the Goodman diagram (in part F). F. Draw the Goodman diagram in graph paper. Use a ruler or straight edge. Clearly specify the title of both the horizontal and vertical axes. Indicate the axis values on both axes. Then, plot the "load line" with the slope calculated in the previous step (E). Read the design value for Sat and write it on the graph. G. Calculate the required diameter "d" of the round link for infinite fatigue life using the value for Sat 1 that you read from the Goodman diagram. The failure theory is (6.)alt = Salt Er where o, is the "equivalent" Von Mises alternating stress (maximum distortion energy theory). Remember that the area of a circle is A