Study On The Implosion Response And Dynamic Characteristics Of Complex Pressure Vessel

Pressure vessel container is an important tool for studying implosion.In the process of implosion,due to the multiple reflection of the shock wave and the complex wave system,the shock wave characteristics are very different from the free-field explosion.At the same time,the load and dynamic response of the structure during implosion are also very different from those during free-field explosion.This paper designs a pressure vessel for implosion experiments,obtains a model for researching,and then researches the shock wave load and dynamic response characteristics of the pressure vessel during implosion.The dynamics characteristics of its working process is also researched.Firstly,this paper designs the explosion-proof structure of pressure vessels according to the design requirements,experiments,national standards and empirical formulas.According to the mechanical principle and mechanical design manual,the container openings and sealing structures including cable channels,pressure control devices,and inlet and drain channels,as well as various supporting structures,experimental auxiliary structures,and quick-opening upper head structures are designed.Pressure vessel model for subsequent implosion research is obtained from above.Then,according to the obtained design results,the multi-layer structure pressure vessel model including superelastic sandwich is divided into an integrated simplified model and a quick-open upper head model including all assembly relationships.Based on the simplified model,a finite element model including the support structure and the base is established.The finite element method is used to research the distribution and the reflection characteristics of shock wave loads during implosion and their relationship with superelastic interlayers.The Quasi-static pressure characteristics of the gas portion of the container under different water depth environments during explosion are also researched.The shock wave’s reflection law on ellipsoidal head,internal quasi-static pressure and their relationship with superelastic interlayer are obtained.Next,each metal part of the pressure vessel is equivalent to a rigid body,the base shock absorber and the super-elastic sandwich are equivalent to a linear shock absorber and a non-linear shock absorber,respectively.The equivalent rigid body motion of pressure vessels with elastic bottoms of different stiffness was researched.Then,according to the simplified model,the finite element method is established to research the distribution characteristics of stress loads,dynamic responses,and impact environments on the pressure vessel as well as the propagation characteristics in different structural layers.The distribution of dynamic responses and impact environments on pressure vessel with different superelastic sandwiches,especially on the location of the installation equipment is also studied.The distribution law of the dynamic response and the impact environment on the pressure vessel are obtained,as well as the danger degree of the equipment are judged according to the impact environment.Finally,based on the design results,a fast opening upper-head finite element model is established.The pressure curve obtained by simulation is is added to the model as the load and the rigid body displacement curve of the outer wall is added to the model as a boundary condition to research the dynamic response and contact force characteristics of the sealing structure and the quick-open door dynamic structure during implosion.Then through the simulation of the hydraulic circuit,the pressure curve at both sidess of the piston rod of the hydraulic cylinder is obtained and added to the model to research the dynamic characteristics during the upper head’s opening process.The dynamic response of the quick-opening door structure during implosion and the dynamic characteristics during its opening process are obtained.