Problem $2$

The structure shown in Fig. $2\mathrm{.}1$ consists of steel members connected via pins. The diameters for

the pins at points $A,B$ and $D$ are $d_A,d_B$ and $d_D$ respectively. Both links BD have thickness of $t$

and width of $3$t$.$ It is known that the allowable shear stress for the pins is equal to ${}_{\text{a}\text{l}\text{l}\text{o}\text{w}},$ while the

allowable normal stress in the links is equal to ${}_{\text{a}\text{l}\text{l}\text{o}\text{w}}.$ Calculate the maximum allowable load P that

can be carried by the structure.

Side view

Figure $2\mathrm{.}1.$ Structure with steel members connected with pins.

Take $d_A=d,d_B=2d,d_D=2d.$

Take $d=4mm,t=4mm,$ and $a=110mm.$

Take ${}_{\text{a}\text{l}\text{l}\text{o}\text{w}}=150$MPa,${}_{\text{a}\text{l}\text{l}\text{o}\text{w}}=350$MPa.