Research On Internal Explosive Loadings And Blast Resistant Characteristics Of Discrete Multi-Layered Explosion Containment Vessels

Explosion containment vessels(ECVs) are used to fully contain the effects of high explosions.They can restrict damage range of explosion shock waves and products,effectively protect personnel and experimental equipment,make observing and testing explosion experiments convenient and safe,and enable recycle of test products to prevent environmental contamination.So it is widely utilized in national defense,military field,explosive processing and scientific research.Nowadays,ECVs have larger volume,heavier weight and thicker wall due to requirements of military application,scientific research and industry production.As they have much larger size, disadvantages of monobloc thick-walled ECVs widely applied now appear.It is difficult and costly to bend,roll and weld very thick steel plates,and to detect and eliminate deep weld seams,and it is hard to ensure the quality of very thick steel plates.Therefore,it is necessary to take research on discrete multi-layered explosion containment vessels(DMECVs) which is convenient and economic in manufacture and can overcome the disadvantages met by large-sized monobloc thick-walled ECVs.Supported by National Natural Science Foundation project "Research on dynamic response and life prediction of confined multi-layered cylindrical shells under intensive dynamic loading"(Project No.10372091) and "Research on design method for multi-layered cylindrical explosion containment vessels"(Project No.50675195), internal explosive loadings and blast resistant characteristics of DMECVs were studied by experiments and numerical simulation in this thesis.The main research work and conclusions are summarized as follows:(1) Study on internal explosive loadings on DMECVs.First,a decoupled numerical model was established to computer internal explosive loadings on DMECVs from the detonation of TNT charges set at their centers.Second,the numerical model was verified by experimental results,which shows that the blast loadings computed are in good agreement with the corresponding experimental results. Then,the similarity of the internal explosive loadings was numerically validated by using this model,which represents that the explosive loadings on a large ECV can be obtained by computing the ones on a scaled model.Finally,characteristics and distribution of the explosive loadings on the same DMECV from a cylindrical charge and from a spherical charge with the same weight,respectively,was investigated.The numerical results show that charge shapes have great effects on the explosive loadings, and the cylindrical charges can not be equally replaced by the spherical ones with the same weight.So it is suggested that the effects of charge shapes shoube be taken into consideration when design and operate ECVs.(2) Research on applicability of decoupled analyses on design of cylindrical ECVs.The maximum effects of small shell deformation and effects of large elastic-plastic shell deformation on the blast loadings on the inner walls of cylindrical ECVs were studied by using the decoupled numerical model and another fluid-structure coupled numerical model,respectively.The results show that the decoupled analysis method will not be too conservative by either to design multiple-time-used ECVs,or to design one-time-used ECV whose allowable plastic deformation is limited to 17.8%.(3) Experimental investigation on blast resistant characteristics of DMECVs. Eight DMECVs,nine discrete multi-layered cylinders and two monobloc cylindrical ECVs were fabricated and tested under internal explosive loadings induced by TNT set at their centers,and some blast resistant characteristics of the DMECVs were revealed.The experimental results show that damping ratios of DMECVs are much larger than those of monobloc cylindrical ECVs,so oscillation of dynamic strains on DMECVs decay much more quickly and there is no beating phenomenon;the DMECVs with a smaller ribbon winding angle has better resistant ability to withstand internal explosion;the DMECVs have three different failure modes:the inner shell broken,steel ribbons fractured,and the inner shell and steel ribbons both bursted;the steel ribbons are fractured both by tension and shear;DMECVs show no obvious scale effects.