lecture

1. Graphical Method (Maxwell’s Diagram)
The graphical analysis was developed by force polygons drawn to scale for
each joint, and then the forces in each member were measured from one
of these force polygons.
In order to draw the Maxwell diagram directly, here are the simple
guidelines:
•Solve the reactions at the supports by solving the equations of
equilibrium for the entire truss,
•Move clockwise around the outside of the truss; draw the force polygon
to scale for the entire truss,
•Take each joint in turn (one-by-one), then draw a force polygon by
treating successively joints acted upon by only two unknown forces,
•Measure the magnitude of the force in each member from the diagram,
•Lastly, note that work proceed from one end of the truss to another, as
this use for checking of balance and connect to other end.

2. A
C
B
E
D
G F

3. A
C
B
E
D
G F

4. A
C
B
E
D
G F

5. A
C
B
E
D
G F

6. Member Diagram Name Length (cm) Stress ( KN ) Remarks

8. SAMPLE PROBLEM
Determine the stress graphically of the Fink truss shown below

9. Bow Notation
.

11. Member
Length Stress
Remarks
( unit CAD ) ( KN )
B -1 Compression
C - 2 Compression
D - 5 Compression
E - 6 Compression
F - 8 Compression
G - 9 Compression
H - 12 Compression
I - 13 Compression
1 - K Tension
3 - K Tension
7 - K Tension
11 - K Tension
13 - K Tension
1 - 2 Compression
2 - 3 Tension
3 - 4 Compression
4 - 5 Tension
4 - 7 Tension
5 - 6 Compression
6 - 7 Tension
7 - 8 Tension
7 - 10 Tension
8 - 9 Compression
9 - 10 Tension
10 - 11 Compression
11 - 12 Tension
12 - 13 Compression