This work aims to research the effects on the early responses of the air-backed plate subjected to the loading generated by the underwater explosion with aluminized explosives.The loading characteristics of underwater...This work aims to research the effects on the early responses of the air-backed plate subjected to the loading generated by the underwater explosion with aluminized explosives.The loading characteristics of underwater explosion for ideal explosive(TNT),aluminized explosives(RS211 and RBUL) are obtained experimentally.The tested aluminized explosives have different energy output compared with TNT.Based on the Taylor plate theory,the early responses of the air-backed steel plate affected by the measured loading is analyzed.The analytical results indicate that the pressure curve of the shock wave within 1 time decay constant is the main factor affecting the kick-off velocity of the plate when cavitation occurring.The velocity responses of the plate produced by the loading of RS211 and RBUL are obviously different with that of an equivalent TNT charge,which also indicates validity and suitability should be noticed in the case of substituting TNT for aluminized explosives.Moreover,the uncertainties in the responses of the plate produced by RS211 and RBUL are much larger than TNT.展开更多
In this study, we focused on the effect of the underwater explosion parameters of multi-point array explosion. The shock wave and bubble parameters of aggregate charge, two charges, and four charges were measured thro...In this study, we focused on the effect of the underwater explosion parameters of multi-point array explosion. The shock wave and bubble parameters of aggregate charge, two charges, and four charges were measured through an underwater explosion test, and their influence on the explosion power field of charge quantity and array distance was analyzed. Results show that the multi-shock wave collision of array explosion can be approximated to a linear superposition, and the interaction of delayed shock wave can be deemed as the increase of the shock wave baseline. Shock wave focusing and delayed superposition increase the shock wave peak pressure. Compared with the aggregate charge, the greater the number of array explosion points is, the higher the impulse and the gain of the bubble peak pressure are. At the same array distance, the smaller the charge quantity is, the higher the bubble impulse will be. At the same charge quantity, the smaller the array distance is, the higher the bubble impulse will be. The bubble period decreases gradually with the increase of the charge quantity, but the test orientation has little effect on the bubble period.展开更多
Reinforced concrete(RC) columns are widely used as supporting structures for high-piled wharfs.The study of damage model of a RC column due to underwater explosion is a critical issue to assess the wharfs antiknock se...Reinforced concrete(RC) columns are widely used as supporting structures for high-piled wharfs.The study of damage model of a RC column due to underwater explosion is a critical issue to assess the wharfs antiknock security.In this study,the dynamic response and damage model of circular RC columns subjected to underwater explosions were investigated by means of scaled-down experiment models.Experiments were carried out in a 10.0 m diameter tank with the water depth of 2.25 m,under different explosive quantities(0.025 kg-1.6 kg),stand-off distances(0.0 m-7.0 m),and detonation depths(0.25 m-2.0 m).The shock wave load and dynamic response of experiment models were measured by configuring sensors of pressure,acceleration,strain,and displacement.Then,the load distribution characteristics,time history of test data,and damage models related to present conditions were obtained and discussed.Three damage models,including bending failure,bending-shear failure and punching failure,were identified.In addition,the experie nce model of shock wave loads on the surface of a RC column was proposed for engineering application.展开更多
Nowadays, the mitigation of damage to a ship caused by the underwater explosion attracts more and more attention from the modern ship designers. In this study, two kinds of scale tests were conducted to investigate th...Nowadays, the mitigation of damage to a ship caused by the underwater explosion attracts more and more attention from the modern ship designers. In this study, two kinds of scale tests were conducted to investigate the effects of polyurea coatings on the blast resistance of hulls subjected to underwater explosion. Firstly, small-scale model tests with different polyurea coatings were carried out. Results indicate that polyurea has a better blast resistance performance when coated on the front face, which can effectively reduce the maximum deflection of the steel plate by more than 20% and reduce the deformation energy by 35.7%-45.4%. Next, a full-scale ship(approximately 50 m × 9 m) under loadings produced by the detonation of 33 kg of spherical TNT charges was tested, where a part of the ship was coated with polyurea on the front face(8 mm + 24 mm) and not on the contrast area. Damage characteristics on the bottom were statistically analyzed based on a 3D scanning technology, indicating that polyurea contributes to enhancing the blast protection of the ship. However, damage results of this test were different from those of the small-scale tests. Moreover, the deformation area of the bottom with polyurea was greatly increased by 40.1% to disperse explosion energy, a conclusion that cannot be drown from the small-scale tests.展开更多
In this study,hydrogen-storage glass microballoons were introduced into emulsion explosives to improve the detonation performance of the explosives.The effect of hydrogen-storage pressure on the detonation characteris...In this study,hydrogen-storage glass microballoons were introduced into emulsion explosives to improve the detonation performance of the explosives.The effect of hydrogen-storage pressure on the detonation characteristics of emulsion explosives was systematically investigated.Detonation velocity experiments shows that the change of sensitizing gas and the increase of hydrogen pressure have different effects on the detonation velocity.The experimental parameters of underwater explosion increase first and then decreases with the increase of hydrogen pressure.The decrease of these parameters indicates that the strength of glass microballoons is the limiting factor to improve the detonation performance of hydrogen-storage emulsion explosives.Compared with the traditional emulsion explosives,the maximum peak pressure of shock wave of hydrogen-storage emulsion explosives increases by 10.6%at 1.0 m and 10.2%at 1.2 m,the maximum values of shock impulse increase by 5.7%at 1.0 m and 19.4%at 1.2 m.The stored hydrogen has dual effects of sensitizers and energetic additives,which can improve the energy output of emulsion explosives.展开更多
Reinforced concrete(RC)structures are common in engineering,and usually exposed to air or water,may be subjected to various blast scenarios.This paper aims to investigate the blast resistance of an airbacked RC slab a...Reinforced concrete(RC)structures are common in engineering,and usually exposed to air or water,may be subjected to various blast scenarios.This paper aims to investigate the blast resistance of an airbacked RC slab against underwater contact explosions(UWCEs).A detailed numerical model based on CLE method considering explosive,water,air,and RC slab is developed to examine the structural behavior of the air-backed RC slab due to UWCEs.At first,the reliability of the numerical method is validated by comparing the numerical results of an UWCE test with experimental data.Then,the difference in dynamic behavior of air-backed and water-backed RC slabs due to UWCEs is explored with the calibrated model.The results indicate that the blast response of the air-backed slab induced by UWCE is fiercer than that of water-backed slab with equal charge mass.In addition,parametric studies are also conducted to explore the effects of the charge mass,standoff distance,reinforcement spacing,concrete compression strength,and boundary condition on the blast performance of the air-backed RC slab.展开更多
Over the past century,the safety of dams has gradually attracted attention from all parties.Research on the dynamic response and damage evolution of dams under extreme loads is the basis of dam safety issues.In recent...Over the past century,the safety of dams has gradually attracted attention from all parties.Research on the dynamic response and damage evolution of dams under extreme loads is the basis of dam safety issues.In recent decades,scholars have studied the responses of dams under earthquake loads,but there is still much room for improvement in experimental and theoretical research on small probability loads such as explosions.In this paper,a 50-m-high concrete gravity dam is used as a prototype dam,and a water explosion model test of a 2.5-m-high concrete gravity dam is designed.The water pressure and the acceleration response of the dam body in the test are analysed.The pressure characteristics and dynamic response of the dam body are assessed.Taking the dam damage test as an example,a numerical model of concrete gravity dam damage is established,and the damage evolution of the dam body is analysed.By combining experiments and numerical simulations,the damage characteristics of the dam body under the action of different charge water explosions are clarified.The integrity of the dam body is well maintained under the action of a small-quantity water explosion,and the dynamic response of the dam body is mainly caused by the shock wave.Both the shock wave and the bubble pulsation cause the dam body to accelerate,and the peak acceleration of the dam body under the action of the bubble pulsation is only one percent of the peak acceleration of the dam body under the action of the shock wave.When subjected to explosions in large quantities of water,the dam body is seriously damaged.Under the action of a shock wave,the dam body produces a secondary acceleration response,which is generated by an internal interaction after the dam body is damaged.The damage evolution process of the dam body under the action of a large-scale water explosion is analysed,and it is found that the shock wave pressure of the water explosion causes local damage to the dam body facing the explosion.After the peak value of the shock wave,the impulse continues to act on the dam body,causing cumulative damage and damage inside the dam body.展开更多
基金This paper is supported by the project of State Key Laboratory of Explosion Science and Technology(Beijing Institute of Technology).The project number is NO.QNKT19-04.
文摘This work aims to research the effects on the early responses of the air-backed plate subjected to the loading generated by the underwater explosion with aluminized explosives.The loading characteristics of underwater explosion for ideal explosive(TNT),aluminized explosives(RS211 and RBUL) are obtained experimentally.The tested aluminized explosives have different energy output compared with TNT.Based on the Taylor plate theory,the early responses of the air-backed steel plate affected by the measured loading is analyzed.The analytical results indicate that the pressure curve of the shock wave within 1 time decay constant is the main factor affecting the kick-off velocity of the plate when cavitation occurring.The velocity responses of the plate produced by the loading of RS211 and RBUL are obviously different with that of an equivalent TNT charge,which also indicates validity and suitability should be noticed in the case of substituting TNT for aluminized explosives.Moreover,the uncertainties in the responses of the plate produced by RS211 and RBUL are much larger than TNT.
文摘In this study, we focused on the effect of the underwater explosion parameters of multi-point array explosion. The shock wave and bubble parameters of aggregate charge, two charges, and four charges were measured through an underwater explosion test, and their influence on the explosion power field of charge quantity and array distance was analyzed. Results show that the multi-shock wave collision of array explosion can be approximated to a linear superposition, and the interaction of delayed shock wave can be deemed as the increase of the shock wave baseline. Shock wave focusing and delayed superposition increase the shock wave peak pressure. Compared with the aggregate charge, the greater the number of array explosion points is, the higher the impulse and the gain of the bubble peak pressure are. At the same array distance, the smaller the charge quantity is, the higher the bubble impulse will be. At the same charge quantity, the smaller the array distance is, the higher the bubble impulse will be. The bubble period decreases gradually with the increase of the charge quantity, but the test orientation has little effect on the bubble period.
基金funded by the National Natural Science Foundation of China(Grant Nos.51578543)。
文摘Reinforced concrete(RC) columns are widely used as supporting structures for high-piled wharfs.The study of damage model of a RC column due to underwater explosion is a critical issue to assess the wharfs antiknock security.In this study,the dynamic response and damage model of circular RC columns subjected to underwater explosions were investigated by means of scaled-down experiment models.Experiments were carried out in a 10.0 m diameter tank with the water depth of 2.25 m,under different explosive quantities(0.025 kg-1.6 kg),stand-off distances(0.0 m-7.0 m),and detonation depths(0.25 m-2.0 m).The shock wave load and dynamic response of experiment models were measured by configuring sensors of pressure,acceleration,strain,and displacement.Then,the load distribution characteristics,time history of test data,and damage models related to present conditions were obtained and discussed.Three damage models,including bending failure,bending-shear failure and punching failure,were identified.In addition,the experie nce model of shock wave loads on the surface of a RC column was proposed for engineering application.
基金the project of State Key Laboratory of Explosion Science and Technology(Beijing Institute of Technology).The project number is NO.QNKT19-04.
文摘Nowadays, the mitigation of damage to a ship caused by the underwater explosion attracts more and more attention from the modern ship designers. In this study, two kinds of scale tests were conducted to investigate the effects of polyurea coatings on the blast resistance of hulls subjected to underwater explosion. Firstly, small-scale model tests with different polyurea coatings were carried out. Results indicate that polyurea has a better blast resistance performance when coated on the front face, which can effectively reduce the maximum deflection of the steel plate by more than 20% and reduce the deformation energy by 35.7%-45.4%. Next, a full-scale ship(approximately 50 m × 9 m) under loadings produced by the detonation of 33 kg of spherical TNT charges was tested, where a part of the ship was coated with polyurea on the front face(8 mm + 24 mm) and not on the contrast area. Damage characteristics on the bottom were statistically analyzed based on a 3D scanning technology, indicating that polyurea contributes to enhancing the blast protection of the ship. However, damage results of this test were different from those of the small-scale tests. Moreover, the deformation area of the bottom with polyurea was greatly increased by 40.1% to disperse explosion energy, a conclusion that cannot be drown from the small-scale tests.
基金financially supported by the National Natural Science Foundation of China under Project NO. 51874267 and NO. 51674229
文摘In this study,hydrogen-storage glass microballoons were introduced into emulsion explosives to improve the detonation performance of the explosives.The effect of hydrogen-storage pressure on the detonation characteristics of emulsion explosives was systematically investigated.Detonation velocity experiments shows that the change of sensitizing gas and the increase of hydrogen pressure have different effects on the detonation velocity.The experimental parameters of underwater explosion increase first and then decreases with the increase of hydrogen pressure.The decrease of these parameters indicates that the strength of glass microballoons is the limiting factor to improve the detonation performance of hydrogen-storage emulsion explosives.Compared with the traditional emulsion explosives,the maximum peak pressure of shock wave of hydrogen-storage emulsion explosives increases by 10.6%at 1.0 m and 10.2%at 1.2 m,the maximum values of shock impulse increase by 5.7%at 1.0 m and 19.4%at 1.2 m.The stored hydrogen has dual effects of sensitizers and energetic additives,which can improve the energy output of emulsion explosives.
基金The supports from the Natural Science Research of Jiangsu Higher Education Institutions of China(21KJB580001)the National Natural Science Foundation of China(Grant No.52209162,51979152)+2 种基金Educational Commission of Hubei Province of China(T2020005)Young Top-notch Talent Cultivation Program of Hubei ProvinceJiangxi Provincial Natural Science Foundation(20212BAB214044)。
文摘Reinforced concrete(RC)structures are common in engineering,and usually exposed to air or water,may be subjected to various blast scenarios.This paper aims to investigate the blast resistance of an airbacked RC slab against underwater contact explosions(UWCEs).A detailed numerical model based on CLE method considering explosive,water,air,and RC slab is developed to examine the structural behavior of the air-backed RC slab due to UWCEs.At first,the reliability of the numerical method is validated by comparing the numerical results of an UWCE test with experimental data.Then,the difference in dynamic behavior of air-backed and water-backed RC slabs due to UWCEs is explored with the calibrated model.The results indicate that the blast response of the air-backed slab induced by UWCE is fiercer than that of water-backed slab with equal charge mass.In addition,parametric studies are also conducted to explore the effects of the charge mass,standoff distance,reinforcement spacing,concrete compression strength,and boundary condition on the blast performance of the air-backed RC slab.
文摘Over the past century,the safety of dams has gradually attracted attention from all parties.Research on the dynamic response and damage evolution of dams under extreme loads is the basis of dam safety issues.In recent decades,scholars have studied the responses of dams under earthquake loads,but there is still much room for improvement in experimental and theoretical research on small probability loads such as explosions.In this paper,a 50-m-high concrete gravity dam is used as a prototype dam,and a water explosion model test of a 2.5-m-high concrete gravity dam is designed.The water pressure and the acceleration response of the dam body in the test are analysed.The pressure characteristics and dynamic response of the dam body are assessed.Taking the dam damage test as an example,a numerical model of concrete gravity dam damage is established,and the damage evolution of the dam body is analysed.By combining experiments and numerical simulations,the damage characteristics of the dam body under the action of different charge water explosions are clarified.The integrity of the dam body is well maintained under the action of a small-quantity water explosion,and the dynamic response of the dam body is mainly caused by the shock wave.Both the shock wave and the bubble pulsation cause the dam body to accelerate,and the peak acceleration of the dam body under the action of the bubble pulsation is only one percent of the peak acceleration of the dam body under the action of the shock wave.When subjected to explosions in large quantities of water,the dam body is seriously damaged.Under the action of a shock wave,the dam body produces a secondary acceleration response,which is generated by an internal interaction after the dam body is damaged.The damage evolution process of the dam body under the action of a large-scale water explosion is analysed,and it is found that the shock wave pressure of the water explosion causes local damage to the dam body facing the explosion.After the peak value of the shock wave,the impulse continues to act on the dam body,causing cumulative damage and damage inside the dam body.
