The cavity characteristics in liquid-filled containers caused by high-velocity impacts represent an important area of research in hydrodynamic ram phenomena.The dynamic expansion of the cavity induces liquid pressure ...The cavity characteristics in liquid-filled containers caused by high-velocity impacts represent an important area of research in hydrodynamic ram phenomena.The dynamic expansion of the cavity induces liquid pressure variations,potentially causing catastrophic damage to the container.Current studies mainly focus on non-deforming projectiles,such as fragments,with limited exploration of shaped charge jets.In this paper,a uniquely experimental system was designed to record cavity profiles in behind-armor liquid-filled containers subjected to shaped charge jet impacts.The impact process was then numerically reproduced using the explicit simulation program ANSYS LS-DYNA with the Structured Arbitrary Lagrangian-Eulerian(S-ALE)solver.The formation mechanism,along with the dimensional and shape evolution of the cavity was investigated.Additionally,the influence of the impact kinetic energy of the jet on the cavity characteristics was analyzed.The findings reveal that the cavity profile exhibits a conical shape,primarily driven by direct jet impact and inertial effects.The expansion rates of both cavity length and maximum radius increase with jet impact kinetic energy.When the impact kinetic energy is reduced to 28.2 kJ or below,the length-to-diameter ratio of the cavity ultimately stabilizes at approximately 7.展开更多
The impact of high-velocity penetrators into liquid-filled containers can generate hydrodynamic ram effects,potentially causing catastrophic structural damage to the container.Previous studies have primarily focused o...The impact of high-velocity penetrators into liquid-filled containers can generate hydrodynamic ram effects,potentially causing catastrophic structural damage to the container.Previous studies have primarily focused on undeformed penetrators,such as fragments or bullets,with limited attention directed toward shaped charge jets.This study investigates the penetration characteristics of shaped charge jets impacting behind-armor liquid-filled containers,with particular emphasis on jet-liquid interactions.A theoretical penetration model incorporating material compressibility and jet stretching was developed based on the virtual origin theory.A high-speed imaging experimental system was designed to capture the jet motion within the container.The impact process was numerically reproduced using ANSYS/LSDYNA,and the effects of standoff and overmatch on jet penetration were analyzed.The results reveal that jet stretching induced by increased standoff enhances the penetration velocity of the jet.A proportional relationship between the stretching factor(λ)and the overmatch parameter(I)was identified,withλranging from approximately 1.22 to 1.38 times I across the studied standoff range(80-220 mm).The findings offer a basis for future studies on the pressure distribution in the liquid and the structural response of containers.展开更多
Aggressive behavior among piglets is considered a harmful social contact.Monitoring weaned piglets with intense aggressive behaviors is paramount for pig breeding management.This study introduced a novel hybrid model,...Aggressive behavior among piglets is considered a harmful social contact.Monitoring weaned piglets with intense aggressive behaviors is paramount for pig breeding management.This study introduced a novel hybrid model,PAB-Mamba-YOLO,integrating the principles of Mamba and YOLO for efficient visual detection of weaned piglets'aggressive behaviors,including climbing body,nose hitting,biting tail and biting ear.Within the proposed model,a novel CSPVSS module,which integrated the Cross Stage Partial(CSP)structure with the Visual State Space Model(VSSM),has been developed.This module was adeptly integrated into the Neck part of the network,where it harnessed convolutional capabilities for local feature extraction and leveraged the visual state space to reveal long-distance dependencies.The model exhibited sound performance in detecting aggressive behaviors,with an average precision(AP)of 0.976 for climbing body,0.994 for nose hitting,0.977 for biting tail and 0.994 for biting ear.The mean average precision(mAP)of 0.985 reflected the model's overall effectiveness in detecting all classes of aggressive behaviors.The model achieved a detection speed FPS of 69 f/s,with model complexity measured by 7.2 G floating-point operations(GFLOPs)and parameters(Params)of 2.63 million.Comparative experiments with existing prevailing models confirmed the superiority of the proposed model.This work is expected to contribute a glimmer of fresh ideas and inspiration to the research field of precision breeding and behavioral analysis of animals.展开更多
基金financial support from the National Natural Science Foundation of China(Grant No.11572159).
文摘The cavity characteristics in liquid-filled containers caused by high-velocity impacts represent an important area of research in hydrodynamic ram phenomena.The dynamic expansion of the cavity induces liquid pressure variations,potentially causing catastrophic damage to the container.Current studies mainly focus on non-deforming projectiles,such as fragments,with limited exploration of shaped charge jets.In this paper,a uniquely experimental system was designed to record cavity profiles in behind-armor liquid-filled containers subjected to shaped charge jet impacts.The impact process was then numerically reproduced using the explicit simulation program ANSYS LS-DYNA with the Structured Arbitrary Lagrangian-Eulerian(S-ALE)solver.The formation mechanism,along with the dimensional and shape evolution of the cavity was investigated.Additionally,the influence of the impact kinetic energy of the jet on the cavity characteristics was analyzed.The findings reveal that the cavity profile exhibits a conical shape,primarily driven by direct jet impact and inertial effects.The expansion rates of both cavity length and maximum radius increase with jet impact kinetic energy.When the impact kinetic energy is reduced to 28.2 kJ or below,the length-to-diameter ratio of the cavity ultimately stabilizes at approximately 7.
基金the financial support from the National Natural Science Foundation of China(Grant No.11572159)。
文摘The impact of high-velocity penetrators into liquid-filled containers can generate hydrodynamic ram effects,potentially causing catastrophic structural damage to the container.Previous studies have primarily focused on undeformed penetrators,such as fragments or bullets,with limited attention directed toward shaped charge jets.This study investigates the penetration characteristics of shaped charge jets impacting behind-armor liquid-filled containers,with particular emphasis on jet-liquid interactions.A theoretical penetration model incorporating material compressibility and jet stretching was developed based on the virtual origin theory.A high-speed imaging experimental system was designed to capture the jet motion within the container.The impact process was numerically reproduced using ANSYS/LSDYNA,and the effects of standoff and overmatch on jet penetration were analyzed.The results reveal that jet stretching induced by increased standoff enhances the penetration velocity of the jet.A proportional relationship between the stretching factor(λ)and the overmatch parameter(I)was identified,withλranging from approximately 1.22 to 1.38 times I across the studied standoff range(80-220 mm).The findings offer a basis for future studies on the pressure distribution in the liquid and the structural response of containers.
基金supported by the National Science and Technology Major Project(No.2022ZD0115702)the Beijing Smart Agriculture Innovation Consortium Project(No.BAIC10-2024)+1 种基金the Innovation Program of Chinese Academy of Agricultural Sciences(No.CAASASTIP-2024-AII)the Central Public-interest Scientific Institution Basal Research Fund(No.JBYW-AII-2023-04).
文摘Aggressive behavior among piglets is considered a harmful social contact.Monitoring weaned piglets with intense aggressive behaviors is paramount for pig breeding management.This study introduced a novel hybrid model,PAB-Mamba-YOLO,integrating the principles of Mamba and YOLO for efficient visual detection of weaned piglets'aggressive behaviors,including climbing body,nose hitting,biting tail and biting ear.Within the proposed model,a novel CSPVSS module,which integrated the Cross Stage Partial(CSP)structure with the Visual State Space Model(VSSM),has been developed.This module was adeptly integrated into the Neck part of the network,where it harnessed convolutional capabilities for local feature extraction and leveraged the visual state space to reveal long-distance dependencies.The model exhibited sound performance in detecting aggressive behaviors,with an average precision(AP)of 0.976 for climbing body,0.994 for nose hitting,0.977 for biting tail and 0.994 for biting ear.The mean average precision(mAP)of 0.985 reflected the model's overall effectiveness in detecting all classes of aggressive behaviors.The model achieved a detection speed FPS of 69 f/s,with model complexity measured by 7.2 G floating-point operations(GFLOPs)and parameters(Params)of 2.63 million.Comparative experiments with existing prevailing models confirmed the superiority of the proposed model.This work is expected to contribute a glimmer of fresh ideas and inspiration to the research field of precision breeding and behavioral analysis of animals.
