Matrix Structural Stiffness - Numerical Structural Analysis - page 203

For member 1, the deformations at joints 1 and 2 are used. Table 4.8 con-
tains the final member-end forces in the local system along with global
deformations used to find those end forces.

Table 4.8. Example 4.20 Global joint stiffness

P L

∆ G

0 ∆ x1 31.22 kips

0 ∆ y1 -0.92 kips

0 419.18 kip-in

q z1

0.3040 -31.22 kips

∆ x2

-0.0207 0.92 kips

∆ y2

-0.0034 q z2 -596.37 kip-in

For member 2, the deformations at joints 2 and 3 are used. Table 4.9 con-
tains the final member-end forces in the local system along with global
deformations used to find those end forces.

Table 4.9. Example 4.20 Global joint stiffness

P L

∆ G

0.3040 18.92 kips

∆ x2

-0.0207 -4.78 kips

∆ y2

-0.0034 -1131.63 kip-in

q z2

0.2852 -18.92 kips

∆ x3

-0.0270 4.78 kips

∆ y3

0.0010 -245.46 kip-in

q z3

For member 3, the deformations at joints 4 and 3 are used. Table 4.10
contains the final member-end forces in the local system along with global
deformations used to find those end forces.

Table 4.10. Example 4.20 Global joint stiffness

P L

D G

0 40.78 kips

∆ x4

0 18.92 kips

∆ y4

0 1659.74 kip-in

q z4

0.2852 -40.78 kips

∆ x3

-0.0270 -18.92 kips

∆ y3

0.0010 1973.46 kip-in

q z3