Page 323 - Marine Structural Design

Chapter 14 qffshore Structures Under Impact Loads 299

possible procedure to account for the indentation effect is to reduce the plastic yield capacity
of the element nodes at the impact point using the procedure suggested by Yao et a1 (1986).
The numerical results are shown in Figures 14.6 (d-e). The effect of strain hardening in these
figures is indicated; when the strain hardening is included, the structure becomes stiffer and
more energy will be absorbed by the ship. Therefore, the deck displacement is smaller, and the
collision force and overturning moment increase.

bl
c- I
woracnonq rate
4285 7 MN m-' 20m

V.1. . 1
0 OS0 100 150 OW 250 100
Indentation (rn)

Figure 14.6 Response Caused by Collision between Supply Ship and
Unmanned Platform
a. Ship-platform collision
b. Local load-indentation relationship for the ship side
(Continued overleaf)