Study On The Dynamic Response Of Cylindrical Container Under Internal Explosive Load

Explosive container is a kind of special sealed pressure vessel,which is used to limit the hazards may caused by its internal explosive,has been widely used in the military,scientific research,production and processing,public safety,and other fields.The explosive containers can be divided into cylindrical containers and spherical containers according to their appearance,and the structure of cylindrical containers is composed of barrels and sealing head.To further understand the mechanical behaviors of the cylindrical container under the internal blast loading,numerical simulation is used in this paper to study the dynamic response of the cylindrical container under the "concentrated charge loading" and "triangular impulse loading",meanwhile,the effects of the charge shape on the internal flow field in a cylindrical container is also analyzed,and the main contents are as follows:(1)Numerical simulation is performed to study the influence of the cylindrical charge shape on the explosive flow field in the cylindrical container.The influence of the length-to-diameter ratio of the charges with a constant mass on the characteristic parameters of the explosive flow field is explored.The trend of the characteristic parameters of different locations on the inner wall of the vessel is analyzed,and the influence laws of the shape of the cylindrical charges on the inner wall’s peak overpressure,impulse and the overpressure time curves are obtained.The results show that when the cylindrical charge mass remains unchanged,the radial peak overpressure will decrease gradually as the axial length of the explosive increases,while the specific impulse value may gradually increase.The fundamental reason is that the charge shape has obvious influence on the reflected waves and subsequent pulse waves in the cylindrical container.(2)Numerical simulation is performed to study the elastic response of the cylindrical vessel under the action of “concentrated charge loading”.The differences in the mechanical behavior of cylindrical containers under different loads of charges with different mass are explored.The dynamic response of different locations of the vessel is analyzed,and the mechanics of strain growth phenomena and buckling phenomena in cylindrical vessels are explored further combined with mode analysis.From the above work,the differences in the mechanical behavior of cylindrical explosive containers under different loads,as well as differences in the response amplitude of the containers in different directions and at different positions are obtained,and the edge effect of the cylindrical explosive containers is presented.On the foundation of the traditional formulae for defining the strain growth factor,and based on the characteristics of the dynamic response of the vessel and the mode analysis results,proposing that the strain growth phenomenon of a cylindrical container should be analyzed in two stages,and the corresponding calculation formulae and analysis results are given.The results show that for the cylindrical vessel with a free boundary,the response of the vessel is a breathing-like mode under the small explosive loading.When the explosive loading becomes larger,the response of the vessel is a breathing-like mode in the early stage and a coupling of breathing-like mode and buckling response in the late stage.For different positions of cylindrical containers,there is an obvious response enhancement near the edge section of the container.(3)Numerical simulation is performed to study the dynamic response of the cylindrical vessel under the action of “triangular pulse loading”.The effect of the length of cylindrical container on the dynamic response of the cylindrical explosive container is investigated,as well as the dynamic response of different locations of the explosive container,and the effect of the length of container on the vibration mode of the cylindrical explosive container is further investigated combined with modal analysis.Through the above study,the differences in mechanical behavior of cylindrical containers with different lengths under the same triangular pulse and the influence law of the container length on the vibration mode of cylindrical vessels are obtained.The results show that the maximum strain value and the maximum deformation of the container gradually increase with the length of the vessel increase,and the fundamental cause of the bending response gradually increases with the length of the container.The fundamental reason is that the bending response gradually increase with the length of the vessel increase.