Figure $1$: Truss with point load

a$)$ Determine the maximum vertical load $P($downward$)$ that can be applied at C considering

the failure normal stresses of $AB,BC,CD,$ and DB are ${}_{T,\text{f}\text{a}\text{i}\text{l}}$ in tension and ${}_{C,\text{f}\text{a}\text{i}\text{l}}$ in

compression.

b$)$ When the truss is under the maximum vertical load $P$ obtained in part a$),$ determine the

minimum diameters of pins at $A,B,C,$ and $D.$ Note that the failure shear stress is ${}_{\text{f}\text{a}\text{i}\text{l}}$ for

all pins.

Take $L=0\mathrm{.}9m,w=9mm,h=9mm.$

Take ${}_{T,\text{f}\text{a}\text{i}\text{l}}=380$MPa,${}_{C,\text{f}\text{a}\text{i}\text{l}}=260$MPa,${}_{\text{f}\text{a}\text{i}\text{l}}=180$MPa.

Use F$.$S$.=2$ for normal stress and F$.$S$.=3$ for shear stress.