106
Case 1. For t. = 3.0 in., E = 100.0 ksi, 10.0 < E < 85.0 ksi,
i i 2
10.0 < E < 200.0 ksi, and with E. between 6.0 and 35.0 ksi,
4 3
-K
E = K (D D ) 2 Eqn. 4.11
3 14 10
K
1
"0.3562 9 0.7185
22.74(E ) + 3.503 x 10 (E )(E ) Eqn. 4.12
2 4 2
r 0 10183 V t )
K = [3.4455 + 0.00841(E )](E ) 2 Eqn. 4.13
2 2 4
The accuracy of the E3 prediction equation presented above appeared
good within the stipulated range of variables listed above. However, it
was not simplified enough to allow the development of a more comprehen
sive equation to include varying Ex and tx values. Multiple linear
regression analyses (39) were performed using various combinations of
variables and transformations in an attempt to develop a relatively
simple E3 prediction equation for t1 values of 3.0, 4.5, and 6.0 in.
The best results from these analyses produced a complex equation
containing 13 variables.
Case 2. For 3.0 < t < 6.0 in., 100.0 < E < 1000.0 ksi,
i l
10.0 < E < 85.0 ksi, and 0.35 < E < 200.0 ksi,
2 4