Answer:
P=361.91 KN
Explanation:
given data:
brackets and head of the screw are made of material with T_fail=120 Mpa
safety factor is F.S=2.5
maximum value of force P=??
solution:
to find the shear stress
              T_allow=T_fail/F.S
                     =120 Mpa/2.5
                     =48 Mpa
we know that,
                V=P
Area for shear head:
               A(head)=π×d×t
                      =π×0.04×0.075
                      =0.003×πm^2
Area for plate:
                A(plate)=π×d×t Â
                      =π×0.08×0.03
                      =0.0024×πm^2
now we have to find shear stress for both head and plate
For head:
                  T_allow=V/A(head)
                  48 Mpa=P/0.003×π         ..(V=P)
                       P =48 Mpa×0.003×π
                        =452.16 KN
For plate:
                  T_allow=V/A(plate)
                  48 Mpa=P/0.0024×π         ..(V=P)
                       P =48 Mpa×0.0024×π
                        =361.91 KN
the boundary load is obtained as the minimum value of force P for all three cases. so the solution is
                        P=361.91 KN
note:
find the attached pic
