Research On Dynamic Response Of Fiberglass Composite Explosion Containment Vessels

Explosion containment vessel (ECV) is a special type of vessel that can effectively protect the personnel and equipment near from the explosion center by restricting shock wave and production of internal explosion. Therefore, it has been widely used in national defense, scientific research, fabrication using explosion process, public security and other fields. In recent years, because of public security problems such as terrorist attacks occurred frequently, the demand for transportable and lightweight ECVs became more heavily all over the world. Composite is preferred material for such ECVs due to its high specific strength, excellent corrosion resistance and outstanding design ability characteristic, thus the research on dynamic response of fiber reinforced composite explosion containment vessel has very important significance.Supported by the National Natural Science Foundation " The Dynamic Response Mechanism of Composite Explosion Containment Vessel based on the Microscopic Damage Mechanics"(No.51275455), the dynamic response of fiber reinforced composite explosion containment vessel was deeply studied in this thesis. The main researches are as follows:(1) Three types of epoxy-glass fiber reinforced composite explosion containment vessels with aluminum alloy liner have been developed and explosion experiments were conducted on them. A new auxiliary structure was designed to ensure the explosives were located at the center of the vessels during the experiments. According to the experiment results, the failure modes of composite ECVs with liner under different explosive charge were analyzed both by macro-observation and microstructure, besides the failure mechanism and its influencing factor were also studied. The results show that:multiple failure modes coexist on the composite ECVs under the internal blast loading, the delamination failure occurred even under very low explosive loading. Fiber break failure is brittle failure while the fracture of aluminum alloy liner is ductile when through crack occurred. The results also indicate that the failure of composite ECV is related to the winding pattern of the composite parts, a special axial delamination is observed when the winding pattern is all annular which leads to a circular through creak. None strain growth phenomenon occurs around the center of the vessel while it appears at the joint of cylinder and head after analyzing the strain data. In addition, the range of anti-explosion capacity of the three types composite ECVs is obtained according to the experimental results which are 1.67%-2.65%,1.99%-2.65% and 3.14%-3.67% respectively, all of them are higher than that of single layer metal ECVs from the literature.(2) Three-dimensional numerical model for calculating the dynamic response of composite ECVs under internal blast loading has been established based on Arbitrary Lagrangian-Eulerian method. Strain rate effect is considered in the finite element model and the delamination failure is successfully achieved using surface-to-surface tie-break contact with cohesive failure criterion. The numerical results are in good agreement with the experiment results when comparing the macroscopical failure and strain data. Based on the numerical model, the dynamic response of aluminum alloy liner under internal blast loading, the failure mechanism of delamination and its behavior evolution, the difference dynamic response of single metal ECV and composite ECV are studied deeply. The results show that:(a) The positon of through creak around the center of vessel under the blast loading of critical explosive charge has a certain randomness, the creak may also propagate in circular direction in addition to the axial direction when the explosive charge is much larger than critical value which lead to complete rupture of the liner; (b) Non_uniform dynamic response of each composite layer include inconsistent amplitude and phase is the main cause of delamination failure. Delamination is extended under each blast loading and new delamination will appear because of that which may lead to delamination fusing to a larger one; (c) Composite ECVs have better deformation resistant capability than the single layer metal ECV when the weight of vessel is same, and the response decreases much more rapidly.(3) The influence of metal liner on the dynamic response of composite ECVs is studied from three aspects:existence of liner, thickness of liner and material of liner. The results indicate that:(a) The decrease speed is higher when the metal liner is added and the anti-explosion capacity also increases because the plastic deformation of liner can absorb some explosion energy; (b) The deformation resistant capability of composite ECV increases with thicker metal liner, but the anti-explosion capacity is not necessarily increase; (c)When the weight of liner is negligible and the thickness are same, material with higher stiffness coefficient is preferred to manufacture liner.(4) The influence of winding pattern on the dynamic response of composite ECVs is also investigated. According to the results, for the whole spiral wingding composite ECVs, the circular load-bearing capacity enhances with the increase of spiral angle and meanwhile the axial load-bearing capacity weakens, the dynamic response also decreases more rapidly. The optimal winding pattern for the single-use composite ECV is also obtained based on the analysis which should be winded alternately with spiral and annular layers and the spiral angle should be around 40 degrees.