Study On Model Manufacture Of Three-dimensional Hydroelastic Submerged Floating Tunnel

Submerged floating tunnel is a complex constrained tubular structure floating below the water.Submerged floating tunnel is used for traffic across the deep water.There has not been a real built-up submerged floating tunnel or one under construction worldwide till now.But the concept and research of it has been in decades.The core of the research is hydrodynamic response of submerged floating tunnel.Hydrodynamic response of submerged floating tunnel is one of the core problems that must be solved in its engineering application.The hysteretic breakthrough in the research is because of the elasticity of the tunnel which is complex constrained and slender.The physical model research is limited to 2D model of rigid pipe section.Establish of 3D hydrodynamic mathematical model lacks sufficient key parameters.It is imperative to carry out research of 3D physical model test.The first task is similarity of hydroelastic model and manufacture of submerged floating tunnel.In this study,we designed the plan of hydroelastic model and manufacture according to gravity similarity criterion and elastic similarity criterion.We manufactured the model and tested its similarity:The center of the tunnel structure is A304 steel rod which is used to elasticity simulation.The length of 3D model is much larger than that of steel bar,so it should be fabricated and then assembled.A nut is designed between the steel bar with strength equal to steel bar.Geometric similarity is satisfied by wrapping non-permeable foam outside the center steel bar.Mass distribution similarity is satisfied by putting steel ring of specified mass into the foam at appropriate location.Similarity tests include geometric similarity,mass similarity,natural frequency in air similarity,deflection similarity,inherent frequency similarity,et al.,which is used for verifying the feasibility of gravity similarity and elastic similarity.Test results show that 3D hydroelastic submerged floating tunnel modelling meet the requirement of gravity similarity and elastic similarity,which can be applied to the test of hydroelastic response of submerged floating tunnel.The simulation method of hydroelastic structure can be generalized to similar research of hydrodynamic test of hydroelastic model.