Experimental And Numerical Simulation Study Of The Failure On The Bolted Flange Connection Structure Between Stages Of Rockets(Missiles)

The bolted flange connection structure is an important part of the rockets(missiles)structure as the familiar connecting method between stages.The geometric continuity of the rockets(missiles)body is destroyed for the strong nonlinear characteristics of the structure,and some problem such as excessive local deformation and stress concentration are easy to occur in the course of loading.Thus,the connection structure is a weak component that is prone to fail,and the load bearing capacity of the whole structure is weakened.In the course of launching,efflux,assembly,and erecting,the rocket or missile may be subjected to the abnormal loads with the extremely unstable amplitude and location,and the failure of the connection structure between stages may be happened.Therefore,it is of great engineering and theoretical significance to investigate the failure mechanism of the connection structure under transient impact and quasi-static load.Several principal experimental specimens has been simplified and manufactured based on the characteristic of the actual connection structure between stages in order to analyze the failure mechanism of the connection structure.By means of experimental measurement and the finite element method,the research is carried out as blow:1.The failure experiments of the connection structure is designed and carried out under quasi-static load.The corresponding loading and data acquisition experimental system has been designed and constructed for the background of the transverse quasi-static load which may be applied to the connection structure between stages in the engineering.And the sequential failure results under transverse quasi-static load of the structure has been achieved in the course of the experiments.The key data such as the force response of the bolts,the loading force and slotted displacement has been collected.The failure mechanism of the connection structure has been investigated in this research,and the data support was provided for the load bearing design and the finite element model.2.The failure experiments of the connection structure is designed and carried out under transient impact load.The failure experiments of drop hammer under axial and transverse two loading conditions has been designed and carried out for the transient abnormal loads with the extremely unstable amplitude and location which may applied to the connection structure between stages in the process of launching and efflux,the key data such as the force response of the bolts,the impact force,the strain response of the key points on the column segment has been collected and the failure mechanism has been analyzed,the data support was provided for the loading capacity design and the finite element model of the structure.3.The finite element method of the failure on the connection structure is studied.The finite element model has been established corresponding to the failure experiments under quasi-static and transient impact load.The “ABAQUS/Explicit” solver was used to simulate the failure process of the connection structure.By comparison of the simulation results and the measured data,it revealed that the results of the finite element model has a good precision,and it can be considered that the conclusion taken by the simulation model was reliable.