Analysis of Truss in 3D 1 Draw a FBD of the whole truss 2 Nu

Analysis of Truss in 3D

1. Draw a FBD of the whole truss.

2. Number the joints (they are called NODES in Finite Element Analysis)

3. Find the coordinates of the nodes

4. Find the unit vectors along the links (or bars) (you can use matlab or excel to do this for you)

5. Write vectorial equations for each joint with the unknown link forces and joint forces on the LHS and the NEGATIVE of the known external forces on the RHS at each joint(equilibrium conditions)

6 . Assemble the equations into a matrix.

7 Compute the determinant of the matrix. If it is zero or very small, then either the force equations or assembly is incorrect or the truss is UNSTABLE.

8 If the determinant is non zero, solve for the unknown forces.

Please, can someone help with the truss?

I\'d really appreciate it. Thanks a lot.

C (38.9\", 91\", 0) B (0, 0, -35.5\") A (0, 0, 35.5\'\') 6 5.8 F (77.8\'\', 91\'\', o) 77 E (77.8\'\', 0, -35.5 5\'11\" D (77.8\",0, 35.5\")

Solution

if a truss is in euallibrium, then each of its joints must be in equalibrium

the method of joints consists of satisying the equllibrium equations for forcing acting on each joint

recall, that the line of action of a force acting on a joint is determined by the geometry of the truss member

the line of action is formed by connecting the twoo nds of each member with a straight line.

since direction of the force is known, the remaining unknown is the magnitude of the force