Problem 1 A simple truss shown in Figure 1 consists of four identical members (AB, BC, CD, and DB). All members have the same length L and the same rectangular cross section with height h and width w (see the figure below). The four members are joined by pins at A, B, C, and D. Note that A and D are double shear connections, whereas B and C are single shear connections, respectively. 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 ot, in tension and oc. 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 Tha for all pins. (For pins A and D use the resultant of the reaction forces to calculate the minimum diameters, for pin B use the largest of the three forces exerted by the three members at B and for pin C, calculate the minimum pin diameter using the largest force among the external force P and the forces exerted by the three members connected at C) Take L=1m,w=8mm,h=5mm. Take of fai) = 250 MPa, 0 fai) = 200 MPa, Tfai| = 150 MPa. Use F.S. = 2 for normal stress and F.S. =3 for shear stress. Question 1 4.5 pts For part a, Find the maximum value of P allowed for member AB. (absolute value and answer in N) |