Research And Application On Model Test Technology Of Jack-up Platform Collision

Jack-up platform is one of the major components for offshore exploitation, for it is the main operating base for exploring, drilling and mining offshore oil and gas. However, ship collision has been one of the main factors threatening the platform, for the collision can cause serious damage to platform structures. It is known that real scale collision tests are the most reliable method to evaluate collision resistance of structures. The fact is that it is too expensive for collision tests of offshore platforms to carry out. Therefore, the scale model tests are necessary and significant to provide basis for validating the analytical method and finite element method. It is very important to do the crashworthiness design for offshore platforms and study the platform deformation mechanism during collision scenario.First, the static and dynamic mechanical tests of typical marine steel have been conducted in this thesis. It has studied and confirmed the parameters of material nonlinear input in finite element simulation analysis.Then, dynamic similar rates of collision between ship and jack-up platform have been derivated by the method of dimensional analysis. The method for scale correction of collision structures has been researched. Based on them, the testing outline has been compiled and tubular and tubular joints drop tests have been carried out. Based on the finite element software ABAQUS, experimental simulation analysis has been developed and modeling technology of collision problem has been perfected. Finally, the collision model test project of whole offshore platform has been designed. The main research work and conclusions are as follows:(1) Quasi static and high speed tensile tests of marine mild steel have been conducted. Based on experimental results, considering the material hardening, failure strain in different grids and strain rate sensitivity, material nonlinear simulation inputs have been researched. The material mechanical performance parameters used in software have been acquired. Then the drop test of stiffened plate model has been conducted. The processe of structural dynamic response under impact loads has been analysised. C ompared with test data and results from simulation calculations, the accuracy of simulation technology has been verified.(2) Based on the method of dimensional analysis, dynamic similar rates of collision between ship and jack-up platform have been derivated. Combined with the finite element simulation technology, simplied collision models have been executed in different scales to verify the validity of similarity criterions. Considering the influences of strain rate sensitivity to structural scale in collision problems, the method for modifng scale errors by changing impact mass has been acquired. Taking scale of pipe collision model for an example, the reliability of correction method has been verified.(3) The drop test project of tubular and tubular joints has been designed and the correlative experiments have been conducted. The impact force, impact process and deformation conditions acquired from experiments have been analysised and discussed. The rules showing the influence of structural forms and impact height on structural dynamic response have been acquired.(4) Based on drop tests of pipe and tube joints, correlative simulation analysis has been developed. Compared with calculation results and experimental data, numerical simulation analysis technology has been improved and comfirmed. Based on the results form numerical calculations, the structural deformation mechanism in typical moments has ben analysised. The influences of impact velocity and impact mass on collision responses of tube structures have been discussed.(5) The process of simplifying collision test model of whole offshore platform has been researched. This paper has identified simplification method that replaces the whole offshore platform model with single leg model. The test model of whole platform and its tools has been preliminarily designed. The test plan has been numerically calculated, lying foundations for the preparation for and development of the following test.