Homework $2$

A load line can be an aid in determining the design factor, $N,$ using the modified Mohr diagram. The assumption is made that stresses increase proportionally as loads increase. Apply the following steps for an example stress state, $A,$ for which $1A=120$MPa and $2A=-550$MPa. The material is Grade $40$A gray cast iron having sut $=276$MPA and suc $=-965$MPa.

Draw the modified Mohr diagram as shown in Figure $5\mathrm{.}9.$

Plot point $A(120,550).$

Draw the load line from the origin through point A until it intersects the failure line on the diagram at the point labeled Af$.$

Determine the distances $OA=?$ and OAf$=?$ by scaling the diagram.

Compute the design factor from $N=OA\frac{f}{A}=$