The Motion Response Analysis Of A Truss Structure Lifting During Splash Zone Transit

In order to carry out offshore lifting engineering operations under severe sea condition in the deep sea numerical simulation rehearsal and safety assessment are essential for marine engineering operations.However,the simulation for the motion response of complex truss structures when entering through the splash zone has not been extensively studied,especially when it comes to the effect of the movement of the crane on the motion of the structure.To this end,the HYSY286 ship,which is the first multi-functional deep-water engineering ship of China with an operation depth of 3,000 meters,as well as the truss-type protection cover of deep-water equipment are chosen to carry out the theoretical study on the real-time simulation calculation of the marine lifting engineering operation in this paper.And the following work is done.Taking the HYSY286 ship and the truss-type protection cover of deep-water equipment for research,the motion and dynamic response of the structure when entering the water in the wave environment are simulated.Relevant knowledge about structure-entering-water theory is studied to establish the ship motion model and the dynamic positioning model.The slender bar model and the line model are introduced.The dynamic calculation on the line model is proposed to earry out motion and force analysis on the structure,and the dynamic calculation on complex truss structure when entering the water is converted to the dynamic calculation on simple slender bar model.The model test on the structure-entering-water process is designed and carried out.The structural model of the truss structure is made.According to the similarity criterion and the physical quantity conversion standard,the relevant conditions of multiple experiments including the single pendulum experiment,the underwater towing experiment,the hydrostatic water slamming experiment,the wave-hover experiment and the entering-water-in-wave experiment are designed.The structural motion of entering water is modeled in SIMA software.Based on this model,the structural motions of entering water with constant speed and various draft leviations are simulated.The tension responses of sling are given through the simulation,which is then compared with those measured results in the corresponding model tests.The calculated errors are all below ten percent,verifying the accuracy of the simulation model.On the base of that,the impacts of ship motion on structural motion response during the entering water process are analyzed deeply.It is found that the ship motion could amplify the structural motion responses and weaken the regularity between them.While tension responses of sling are more irrfluenced during the entering process than after that,which indicates the significance of ship motion to the research of structural motion response in the process of entering water.