On the basis of the theories of mechanics of explosive and rock fracture mechanics, the mechanism of crack initiation and its expansion of directional fracture controlled blasting with shaped charges in rock were stud...On the basis of the theories of mechanics of explosive and rock fracture mechanics, the mechanism of crack initiation and its expansion of directional fracture controlled blasting with shaped charges in rock were studied, then the blasting parameters were designed and tested by a model test in laboratory and field experiment. The experimental and test results showed that the energy from blasting is directionally concentrated for the cumulative action. The directional expansion of cracks is satisfactory, the results of the model test and field test suggested that the orientation fracture blasting with shaped charge is a good means of excavating tunnels or cutting rock.展开更多
Penetration and internal blast behavior of reactive liner enhanced shaped charge against concrete space were investigated through experiments and simulations.The volume of the enclosed concrete space is about 15 m^(3)...Penetration and internal blast behavior of reactive liner enhanced shaped charge against concrete space were investigated through experiments and simulations.The volume of the enclosed concrete space is about 15 m^(3).The reactive liner enhanced shaped charge utilizes reactive copper double-layered liner,which is composed of an inner copper liner and an outer reactive liner,while the reactive material liner is fabricated by PTFE/Al(Polytetrafluoroethylene/Aluminum)powders through cold-pressing and sintering.Static explosion experiments show that,compared with the shaped charge which utilizes copper liner,the penetration cavity diameter and spalling area of concrete by the novel shaped charge were enlarged to 2 times and 4 times,respectively.Meanwhile,the following reactive material had blast effect and produced significant overpressure inside the concrete closed space.Theoretical analysis indicates concrete strength and detonation pressure of reactive material both affect the penetration cavity diameter.To the blast behavior of reactive material inside the concrete space,developing TNT equivalence model and simulated on AUTODYN-3 D for analysis.Simulation results reproduced propagation process of the shock wave in concrete space,and revealed multi-peaks phenomenon of overpressure-time curves.Furthermore,the empirical relationship between the peak overpressure and relative distance for the shock wave of reactive material was proposed.展开更多
Cost and safety are important considerations when designing the thickness of a protective reinforced concrete shelter.The blast perforation limit(BPL)is the minimum concrete shelter thickness that resists perforation ...Cost and safety are important considerations when designing the thickness of a protective reinforced concrete shelter.The blast perforation limit(BPL)is the minimum concrete shelter thickness that resists perforation under blast loading.To investigate the influence of the depth of embedment(DOE)and length-to-diameter ratio(L/D)of an explosive charge on the BPL,the results of an explosion test using a slender explosive partially embedded in a reinforced concrete slab were used to validate a refined finite element model.This model was then applied to conduct more than 300 simulations with strictly controlled variables,obtaining the BPLs for various concrete slabs subjected to charge DOEs ranging from0 to∞and L/D values ranging from 0.89 to 6.87.The numerical results were compared with the experimental results from published literature,further verifying the reliability of the simulation.The findings indicate that for the same explosive charge mass and L/D,the greater the DOE,the larger the critical residual thickness(Rc,defined as the difference between the BPL and DOE)up to a certain constant value;for the same explosive charge mass and DOE,the greater the L/D,the smaller the Rc.Thus,corresponding DOE and shape coefficients were introduced to derive a new equation for the BPL,providing a theoretical approach to the design and safety assessment of protective structures.展开更多
Based on the action mechanism of linear shaped charge(LSC), penetration performance of LSC on rock was studied. The optimal standoff and the vertex angle of LSC wese studied and determined by lab experiments. Through ...Based on the action mechanism of linear shaped charge(LSC), penetration performance of LSC on rock was studied. The optimal standoff and the vertex angle of LSC wese studied and determined by lab experiments. Through cutting sand-cement grout samples, the spacing interval of boreholes can approach 17.5 times of the bore-hole’s diameter, and the result of the directional expansion of crack is satisfactory. The result of field experiment indicates cutting effect is very good, the ruggedness in fracture plane is less than 50 mm, the rate of half-hole marks is nearly 100 %, and the crack inspection shows that there is no damage in the internal of the cutting part. All these suggest that the orientation fracture blasting with LSC is a good means in directional fracture controlled blasting and is worth popularizing widely.展开更多
Blasting and shaped charges are the main forms of underwater weapons,and their near-field underwater explosions(UNDEX)can severely damage structures.Therefore,it is of great importance to study underwater explosive lo...Blasting and shaped charges are the main forms of underwater weapons,and their near-field underwater explosions(UNDEX)can severely damage structures.Therefore,it is of great importance to study underwater explosive load characteristics of different forms of charges.The full physical process of a typical underwater explosion of a sphere/column blasting charge and a shaped charge was simulated using the Eulerian method.The loading characteristics of the underwater blast shock wave and bubble,as well as the projectile,were studied.The results show that the shock wave loads of spherical,cylindrical,and polygonal charges propagate outward in spherical,ellipsoidal–spherical and ellipsoidal–spherical wavefronts,respectively.When the shock wave reaches 16 times the distance-to-diameter ratio,its surface is approximately spherical.In addition,in the shaped charge underwater explosion,the shaped charge liner cover absorbs 30°–90°of the shock wave energy and some of the bubble energy to form a high-speed shaped penetrator.Spherical,ellipsoidal,and ellipsoidal bubbles are generated by underwater explosions of spherical,cylindrical,and shaped charges,respectively.The obtained results provide a reference for evaluating the power of underwater weapons.展开更多
LS-PrePost是一款功能强大、操作便捷的爆炸仿真软件。*INITIAL_VOLUME_FRACTION_GEOMETRY和*LOAD_BLAST是LS-PrePost中的关键字卡片,而SPH是一种光滑粒子流体动力学方法,都可以用来施加爆炸载荷。为研究球形装药爆炸仿真建模方法,使用...LS-PrePost是一款功能强大、操作便捷的爆炸仿真软件。*INITIAL_VOLUME_FRACTION_GEOMETRY和*LOAD_BLAST是LS-PrePost中的关键字卡片,而SPH是一种光滑粒子流体动力学方法,都可以用来施加爆炸载荷。为研究球形装药爆炸仿真建模方法,使用以上方法进行建模,分析不同建模方法的优缺点及适用场景。选择最优建模方法研究1 kg TNT炸药不同形状装药爆炸产生空气冲击波的不同。本文在研究爆炸仿真建模现状的基础上,查阅文献资料,选择最优建模方法。在经过验证的有限元模型上进行爆炸仿真,模拟实验仅改变装药形状参数,对球形、柱形、方形装药的有限元爆炸模型进行求解,得到不同比例距离下的超压峰值,制作图表比较各组超压峰值数据的差异。结果表明,在比例距离小于等于1.0 m·kg^(-1/3)时,柱形装药的超压峰值与球形装药更接近,而方形装药超压峰值与球形装药差异更大;随着比例距离的增加,柱形装药的峰值超压与球形装药的比值变化不大,而方形装药的峰值超压与球形装药的比值逐渐增加,变化较大。不同装药形状对于爆炸产生的冲击波超压的影响是不容忽视的,在研究实际爆炸案件的装药及其爆炸破坏作用时,应尽可能采用最接近实际情况的装药形状。在通过爆炸仿真方法研究问题时,也要选择合适的建模方法和装药条件,才能保证分析结果的准确可靠。展开更多
文摘On the basis of the theories of mechanics of explosive and rock fracture mechanics, the mechanism of crack initiation and its expansion of directional fracture controlled blasting with shaped charges in rock were studied, then the blasting parameters were designed and tested by a model test in laboratory and field experiment. The experimental and test results showed that the energy from blasting is directionally concentrated for the cumulative action. The directional expansion of cracks is satisfactory, the results of the model test and field test suggested that the orientation fracture blasting with shaped charge is a good means of excavating tunnels or cutting rock.
基金supported by National Natural Science Foundation of china[grant number:U1730112]。
文摘Penetration and internal blast behavior of reactive liner enhanced shaped charge against concrete space were investigated through experiments and simulations.The volume of the enclosed concrete space is about 15 m^(3).The reactive liner enhanced shaped charge utilizes reactive copper double-layered liner,which is composed of an inner copper liner and an outer reactive liner,while the reactive material liner is fabricated by PTFE/Al(Polytetrafluoroethylene/Aluminum)powders through cold-pressing and sintering.Static explosion experiments show that,compared with the shaped charge which utilizes copper liner,the penetration cavity diameter and spalling area of concrete by the novel shaped charge were enlarged to 2 times and 4 times,respectively.Meanwhile,the following reactive material had blast effect and produced significant overpressure inside the concrete closed space.Theoretical analysis indicates concrete strength and detonation pressure of reactive material both affect the penetration cavity diameter.To the blast behavior of reactive material inside the concrete space,developing TNT equivalence model and simulated on AUTODYN-3 D for analysis.Simulation results reproduced propagation process of the shock wave in concrete space,and revealed multi-peaks phenomenon of overpressure-time curves.Furthermore,the empirical relationship between the peak overpressure and relative distance for the shock wave of reactive material was proposed.
基金supported by the National Natural Science Foundation of China(Grant No.51978166)。
文摘Cost and safety are important considerations when designing the thickness of a protective reinforced concrete shelter.The blast perforation limit(BPL)is the minimum concrete shelter thickness that resists perforation under blast loading.To investigate the influence of the depth of embedment(DOE)and length-to-diameter ratio(L/D)of an explosive charge on the BPL,the results of an explosion test using a slender explosive partially embedded in a reinforced concrete slab were used to validate a refined finite element model.This model was then applied to conduct more than 300 simulations with strictly controlled variables,obtaining the BPLs for various concrete slabs subjected to charge DOEs ranging from0 to∞and L/D values ranging from 0.89 to 6.87.The numerical results were compared with the experimental results from published literature,further verifying the reliability of the simulation.The findings indicate that for the same explosive charge mass and L/D,the greater the DOE,the larger the critical residual thickness(Rc,defined as the difference between the BPL and DOE)up to a certain constant value;for the same explosive charge mass and DOE,the greater the L/D,the smaller the Rc.Thus,corresponding DOE and shape coefficients were introduced to derive a new equation for the BPL,providing a theoretical approach to the design and safety assessment of protective structures.
文摘Based on the action mechanism of linear shaped charge(LSC), penetration performance of LSC on rock was studied. The optimal standoff and the vertex angle of LSC wese studied and determined by lab experiments. Through cutting sand-cement grout samples, the spacing interval of boreholes can approach 17.5 times of the bore-hole’s diameter, and the result of the directional expansion of crack is satisfactory. The result of field experiment indicates cutting effect is very good, the ruggedness in fracture plane is less than 50 mm, the rate of half-hole marks is nearly 100 %, and the crack inspection shows that there is no damage in the internal of the cutting part. All these suggest that the orientation fracture blasting with LSC is a good means in directional fracture controlled blasting and is worth popularizing widely.
基金supported by the National Natural Science Foundation of China(Grant Nos.52271307,52061135107,52192692 and 11802025)the Liaoning Excellent Youth Fund Program(Grant No.2023JH3/10200012)+2 种基金the Opening Project of State Key Laboratory of Explosion Science and Technology(Grant No.KFJJ21-09M)the Liaoning Revitalization Talents Program(Grant No.XLYC1908027)the Fundamental Research Funds for the Central Universities(Grant Nos.DUT20RC(3)025,DUT20TD108,DUT20LAB308).
文摘Blasting and shaped charges are the main forms of underwater weapons,and their near-field underwater explosions(UNDEX)can severely damage structures.Therefore,it is of great importance to study underwater explosive load characteristics of different forms of charges.The full physical process of a typical underwater explosion of a sphere/column blasting charge and a shaped charge was simulated using the Eulerian method.The loading characteristics of the underwater blast shock wave and bubble,as well as the projectile,were studied.The results show that the shock wave loads of spherical,cylindrical,and polygonal charges propagate outward in spherical,ellipsoidal–spherical and ellipsoidal–spherical wavefronts,respectively.When the shock wave reaches 16 times the distance-to-diameter ratio,its surface is approximately spherical.In addition,in the shaped charge underwater explosion,the shaped charge liner cover absorbs 30°–90°of the shock wave energy and some of the bubble energy to form a high-speed shaped penetrator.Spherical,ellipsoidal,and ellipsoidal bubbles are generated by underwater explosions of spherical,cylindrical,and shaped charges,respectively.The obtained results provide a reference for evaluating the power of underwater weapons.
文摘LS-PrePost是一款功能强大、操作便捷的爆炸仿真软件。*INITIAL_VOLUME_FRACTION_GEOMETRY和*LOAD_BLAST是LS-PrePost中的关键字卡片,而SPH是一种光滑粒子流体动力学方法,都可以用来施加爆炸载荷。为研究球形装药爆炸仿真建模方法,使用以上方法进行建模,分析不同建模方法的优缺点及适用场景。选择最优建模方法研究1 kg TNT炸药不同形状装药爆炸产生空气冲击波的不同。本文在研究爆炸仿真建模现状的基础上,查阅文献资料,选择最优建模方法。在经过验证的有限元模型上进行爆炸仿真,模拟实验仅改变装药形状参数,对球形、柱形、方形装药的有限元爆炸模型进行求解,得到不同比例距离下的超压峰值,制作图表比较各组超压峰值数据的差异。结果表明,在比例距离小于等于1.0 m·kg^(-1/3)时,柱形装药的超压峰值与球形装药更接近,而方形装药超压峰值与球形装药差异更大;随着比例距离的增加,柱形装药的峰值超压与球形装药的比值变化不大,而方形装药的峰值超压与球形装药的比值逐渐增加,变化较大。不同装药形状对于爆炸产生的冲击波超压的影响是不容忽视的,在研究实际爆炸案件的装药及其爆炸破坏作用时,应尽可能采用最接近实际情况的装药形状。在通过爆炸仿真方法研究问题时,也要选择合适的建模方法和装药条件,才能保证分析结果的准确可靠。
