6.1 Benchmark Problems
103
(a)
0
0.5
1
1.5
2
2.5
0
0.005
0.01
0.015
0.02
0.025
0.03
0.035
0.04
0.045
0.05
Load (lb/in
2
)
Transverse deflection (|w|/h)
+q, LRT56 (SH851URI)
+q, Reddy (1989)
+q, Basar (1993)
-q, LRT56 (SH851URI)
-q, Reddy (1989)
-q, Basar (1993)
Linear (SH851URI)
(b)
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
5
Transverse deflection (|w|/h)
Load (lb/in
2
)
+q, LRT56 (SH851URI)
+q, Reddy (1989)
+q, Basar (1993)
-q, LRT56 (SH851URI)
-q, Reddy (1989)
-q, Basar (1993)
Fig. 6.2 Load-displacement curves of hinged cross-ply plate under a uniform pressure: a small
pressure, b large pressure, reprinted from Ref. [5], copyright 2014, with permission from ELSEVIER
are under the assumption of small or moderate rotations. The LRT5 theory contains
all the nonlinear strain-displacement relations. Since moderate rotations are assumed
in the theory, the sixth parameter is neglected
1
v 3 = 0, that means no updating of the
rotations. Therefore, LRT5 theory cannot predict results more accurate than MRT5
theory.
Investigating on full integration and reduced integration elements, SH851FI and
SH851URI, there are big discrepancies between the results of LRT56 using the two
elements. The reason can be explained that the full integration converges to the
exact value slower than the uniformly reduced integration. The gap can be reduced