The document describes Maxwell's diagram, a graphical method for analyzing trusses. It involves drawing force polygons to scale for each joint to determine member forces. The process includes solving for support reactions, drawing a force polygon around the entire truss clockwise, then drawing individual force polygons for each joint with two unknown forces to measure member forces from the diagram. As an example, it provides a sample problem to determine stresses in a Fink truss using this graphical method.

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