The demand of oil and natural gas globally increases, resource development area is moving in deep sea. Floating and flexible offshore structures such as Semi-submersible, Spar, and FPSO have been widely used. Core equipment of floating offshore structures is composed of a number of slender bodies. These flexible structures are possibly to receive damage by marine environment such as waves and current. Moreover, flexible risers are easily damaged by the exciting force due to the motion of the floating body. These structures move in three-dimensions, because inline and transverse responses occurred by various forces. Thus, research and many experiments for the dynamic behavior analysis of the slender body are being carried out.
Generally, risers used in the development of oil and gas resource are composed of a steel pipe. However, the OTEC risers are not possible to use a steel pipe, using a flexible material such as polyethylene. To conduct the optimal design of flexible offshore plant, there is a need for dynamic behavior analysis of the slender bodies those are manufactured by various materials. In this study, used the three-dimensional motion measurement device to analyze the displacement of riser models induced external force factors forced oscillation by riser linked to forced oscillation device in the current and regular wave condition.