This paper studies intensively the problems of ship-platform collision
. The ship and platform are treated as one structural system connected
with spring elements and then motion equation of the collision system
is established. A nonlinear force-displacement relationship is derive
d for the simulation of local dent in a hit member and the yield surfa
ce of a dented tubular section is developed to consider the reduction
of load carrying capacity of hit members. Large deformations, plastici
ty and strain-hardening of the beam-column element are taken into acco
unt by combining the elastic large displacement analysis theory with t
he plastic node method. The effect of the hydrodynamic forces acting o
n the platform, the rubber fender the property of the local dent and t
he buckling behavior of beam-column on collision are analyzed. The num
erical simulation of the nonlinear dynamic response is carried out by
Wilson theta method with updated Newton-Raphson iteration. And the num
erical example of the dynamic response of a offshore platform in ship-
platform collision is also present.