The penetration of shaped charge jets into targets at high velocities is significantly influenced by the compressibility effect,while at low velocities,the strength effect becomes predominant.In the latter regime,mate...The penetration of shaped charge jets into targets at high velocities is significantly influenced by the compressibility effect,while at low velocities,the strength effect becomes predominant.In the latter regime,material strength dictates the resistance to plastic deformation and flow,a contrast to the shockwave-dominated interactions where compressibility is key.This paper presents a self-consistent compressible penetration theory that considers both the axial penetration and radial crater growth of shaped charge jets into targets.An integrated approach where the axial and radial dynamics are coupled has been proposed,influencing each other through shared physical principles rather than being treated as separate,empirically linked phenomena.The presented theory is rooted in the compressible Bernoulli equation and the linear Rankine-Hugoniot relation.These foundational equations are employed to accurately model the high-pressure shock state and subsequent material flow at the jet-target interface,providing a robust physical basis for the penetration model.Notably,it considers the target material's compressibility,which elevates the pressure at the jet-target interface beyond that observed with incompressible materials.This pressure increase is directly proportional to the target's degree of compressibility.As such,this model of compressible penetration reorients the analytical approach:rather than merely estimating penetration resistance,it determines this value from the target material's specific compressibility and yield strength.This shift from empirical correlations to a physics-based derivation of penetration resistance enhances the model's predictive power,particularly for novel target materials or engagement conditions outside established experimental datasets.This investigation establishes a quantitative link between the material's yield strength and its penetration resistance.The accuracy of this penetration resistance value is paramount,as it significantly influences the predicted crater diameter;indeed,the crater diameter's sensitivity to this resistance underscores the necessity for its precise determination.Ultimately,by integrating the yield strength of the target material,this framework enables the prediction of both the penetration depth and the resultant crater diameter from a shaped charge jet.The theory's validation involved two experimental sets:the first focused on shaped charge jet penetration into 45#steel at varied stand-offs,while the second utilized targets of high-to ultrahigh-strength steel-fiber reactive powder concrete(RPC)with differing strength characteristics.These experimental campaigns were specifically chosen to test the theory against both ductile metallic alloys,where plastic flow is significant,and advanced quasi-brittle cementitious composites,presenting a broad spectrum of material responses and penetration challenges.Resulting hole profiles derived from theoretical calculations demonstrated a strong correspondence with empirical measurements for both material types.展开更多
By analyzing core data from an offshore Gulf of Mexico reservoir and developing analytical solutions,it can be demonstrated that laboratory measurements on pore-volume compressibility include artifacts,leading to a mi...By analyzing core data from an offshore Gulf of Mexico reservoir and developing analytical solutions,it can be demonstrated that laboratory measurements on pore-volume compressibility include artifacts,leading to a misinterpretation of porosity and permeability trends.A systematic evaluation of poro-elastic changes in pore volumes(and quantifying any consequent fluid expulsion during reservoir compaction)suggests that poro-elastic relaxation may enhance fluid production rates from deep reservoirs by up to 25%.This value may be inadvertently inflated if the core samples used for pore-volume compressibility measurements suffered from handling damage.Nonetheless,poro-elastic fluid expulsion from the pores in producing reservoirs can provide additional lift and thus may enhance the recovery factor.Therefore,the possible contribution to well performance from poro-elastic production drive mechanisms ought to be carefully evaluated in reserves estimation.Reversely,injection wells may encounter poro-elastic suppression of injectivity due to elastic resistance,which would adversely affect the storage coefficient.By integrating geomechanical reservoir response with traditional fluid production models,reservoir model predictions of production under pressure depletion and injection conditions will be more accurate.The new insights reported here are essential for optimizing well performance,improving reservoir management,and extending the economic life of geological reservoirs.However,caution is warranted regarding pore-volume compressibility measurements.To what degree laboratory measurements of pore-volume compressibility measure true values or mainly record handling damage could not be conclusively settled in the present study.展开更多
1.Introduction Compared with the widely used vapor-compression refrigeration,solid-state cooling based on phase transition offers higher ef-ficiency,environmental friendliness,and smaller volume[1,2].The phase transit...1.Introduction Compared with the widely used vapor-compression refrigeration,solid-state cooling based on phase transition offers higher ef-ficiency,environmental friendliness,and smaller volume[1,2].The phase transition of solid refrigerants can be triggered by external fields,i.e.,magnetic fields[3-5],electric fields[6,7].展开更多
Accurately modeling real network dynamics is a grand challenge in network science.The network dynamics arise from node interactions,which are shaped by network topology.Real networks tend to exhibit compact or highly ...Accurately modeling real network dynamics is a grand challenge in network science.The network dynamics arise from node interactions,which are shaped by network topology.Real networks tend to exhibit compact or highly optimized topologies.But the key problems arise:how to compress a network to best enhance its compactness,and what the compression limit of the network reflects?We abstract the topological compression of complex networks as a dynamic process of making them more compact and propose the local compression modulus that plays a key role in effective compression evolution of networks.Subsequently,we identify topological compressibility-a general property of complex networks that characterizes the extent to which a network can be compressed-and provide its approximate quantification.We anticipate that our findings and established theory will provide valuable insights into both dynamics and various applications of complex networks.展开更多
探究了不同碳纤维/玄武岩纤维(carbon fiber/basalt fiber,CF/BF)配比的混杂层合板在弹道冲击及冲击后压缩(compression after impact,CAI)性能方面的表现,结果表明,玄武岩纤维显著提升了混杂层合板的能量吸收能力。采用C扫描、电子显...探究了不同碳纤维/玄武岩纤维(carbon fiber/basalt fiber,CF/BF)配比的混杂层合板在弹道冲击及冲击后压缩(compression after impact,CAI)性能方面的表现,结果表明,玄武岩纤维显著提升了混杂层合板的能量吸收能力。采用C扫描、电子显微镜和扫描电镜分析了材料的损伤机制,揭示了材料性能提升的内在机理。另一方面,混杂层合板的初始压缩强度随玄武岩纤维含量的增加而下降。在混杂层合板的能量吸收能力增强与初始压缩强度下降的共同作用下,CAI测试中受损层合板的残余压缩强度呈局部波动趋势。研究结果可为轻量化、高抗冲击复合材料的结构设计提供指导。展开更多
In order to describe the compressibility of traffic flows and determine the compression factors, the Mach number of gas dynamics is introduced, and the concept and the formula of the compression factor are obtained. A...In order to describe the compressibility of traffic flows and determine the compression factors, the Mach number of gas dynamics is introduced, and the concept and the formula of the compression factor are obtained. According to the concept of the compression factor and its differential equation, a stop-wave model is built. The theoretical value and the observed one are obtained by the survey data in Changchun city. The relative error between the two values is 20. 3%. The accuracy is improved 39% compared with the result from the traditional stop-wave model. The results show that the traffic flow is compressible, and the methods of research on gas compressibility is also applicable to the traffic flow. The stop-wave model obtained by the compression factor can better describe the phenomenon of the stop wave at a signalized intersection when compared with the traditional stop-wave model.展开更多
基金the Fundamental Research Funds for the Central Universities of Nanjing University of Science and Technology(CN)under Grant No.30924010803。
文摘The penetration of shaped charge jets into targets at high velocities is significantly influenced by the compressibility effect,while at low velocities,the strength effect becomes predominant.In the latter regime,material strength dictates the resistance to plastic deformation and flow,a contrast to the shockwave-dominated interactions where compressibility is key.This paper presents a self-consistent compressible penetration theory that considers both the axial penetration and radial crater growth of shaped charge jets into targets.An integrated approach where the axial and radial dynamics are coupled has been proposed,influencing each other through shared physical principles rather than being treated as separate,empirically linked phenomena.The presented theory is rooted in the compressible Bernoulli equation and the linear Rankine-Hugoniot relation.These foundational equations are employed to accurately model the high-pressure shock state and subsequent material flow at the jet-target interface,providing a robust physical basis for the penetration model.Notably,it considers the target material's compressibility,which elevates the pressure at the jet-target interface beyond that observed with incompressible materials.This pressure increase is directly proportional to the target's degree of compressibility.As such,this model of compressible penetration reorients the analytical approach:rather than merely estimating penetration resistance,it determines this value from the target material's specific compressibility and yield strength.This shift from empirical correlations to a physics-based derivation of penetration resistance enhances the model's predictive power,particularly for novel target materials or engagement conditions outside established experimental datasets.This investigation establishes a quantitative link between the material's yield strength and its penetration resistance.The accuracy of this penetration resistance value is paramount,as it significantly influences the predicted crater diameter;indeed,the crater diameter's sensitivity to this resistance underscores the necessity for its precise determination.Ultimately,by integrating the yield strength of the target material,this framework enables the prediction of both the penetration depth and the resultant crater diameter from a shaped charge jet.The theory's validation involved two experimental sets:the first focused on shaped charge jet penetration into 45#steel at varied stand-offs,while the second utilized targets of high-to ultrahigh-strength steel-fiber reactive powder concrete(RPC)with differing strength characteristics.These experimental campaigns were specifically chosen to test the theory against both ductile metallic alloys,where plastic flow is significant,and advanced quasi-brittle cementitious composites,presenting a broad spectrum of material responses and penetration challenges.Resulting hole profiles derived from theoretical calculations demonstrated a strong correspondence with empirical measurements for both material types.
基金support provided by the College of Petroleum Engineering&Geosciences(CPG)at King Fahd University of Petroleum&Minerals(KFUPM).
文摘By analyzing core data from an offshore Gulf of Mexico reservoir and developing analytical solutions,it can be demonstrated that laboratory measurements on pore-volume compressibility include artifacts,leading to a misinterpretation of porosity and permeability trends.A systematic evaluation of poro-elastic changes in pore volumes(and quantifying any consequent fluid expulsion during reservoir compaction)suggests that poro-elastic relaxation may enhance fluid production rates from deep reservoirs by up to 25%.This value may be inadvertently inflated if the core samples used for pore-volume compressibility measurements suffered from handling damage.Nonetheless,poro-elastic fluid expulsion from the pores in producing reservoirs can provide additional lift and thus may enhance the recovery factor.Therefore,the possible contribution to well performance from poro-elastic production drive mechanisms ought to be carefully evaluated in reserves estimation.Reversely,injection wells may encounter poro-elastic suppression of injectivity due to elastic resistance,which would adversely affect the storage coefficient.By integrating geomechanical reservoir response with traditional fluid production models,reservoir model predictions of production under pressure depletion and injection conditions will be more accurate.The new insights reported here are essential for optimizing well performance,improving reservoir management,and extending the economic life of geological reservoirs.However,caution is warranted regarding pore-volume compressibility measurements.To what degree laboratory measurements of pore-volume compressibility measure true values or mainly record handling damage could not be conclusively settled in the present study.
基金supported by the National Natural Science Foundation of China(Nos.52371106,52371025,52171154,51871076,52071118,and 52301223)Interdisciplinary Research Foundation of HIT(No.IR2021201)+4 种基金the Natural Science Foundation of Ningbo City(No.2023J346)supported by Zhejiang Provincial Natural Science Foundation of China(No.LQ24E010004)supported by the National Science Foundation(NSF)-Earth Sciences(No.EAR-1634415)the Department of Energy(DOE)-GeoSciences(No.DE-FG02-94ER14466)supported by DOE-BES(No.DE-AC02-06CH11357).
文摘1.Introduction Compared with the widely used vapor-compression refrigeration,solid-state cooling based on phase transition offers higher ef-ficiency,environmental friendliness,and smaller volume[1,2].The phase transition of solid refrigerants can be triggered by external fields,i.e.,magnetic fields[3-5],electric fields[6,7].
基金supported inpart by the National Natural Science Foundation of China(Grant No. 12371088)the Innovative Research Group Project of Natural Science Foundation of Hunan Provinceof China (Grant No. 2024JJ1008)in part by the Australian Research Council (ARC) through the Discovery Projects scheme (Grant No. DP220100580)。
文摘Accurately modeling real network dynamics is a grand challenge in network science.The network dynamics arise from node interactions,which are shaped by network topology.Real networks tend to exhibit compact or highly optimized topologies.But the key problems arise:how to compress a network to best enhance its compactness,and what the compression limit of the network reflects?We abstract the topological compression of complex networks as a dynamic process of making them more compact and propose the local compression modulus that plays a key role in effective compression evolution of networks.Subsequently,we identify topological compressibility-a general property of complex networks that characterizes the extent to which a network can be compressed-and provide its approximate quantification.We anticipate that our findings and established theory will provide valuable insights into both dynamics and various applications of complex networks.
文摘探究了不同碳纤维/玄武岩纤维(carbon fiber/basalt fiber,CF/BF)配比的混杂层合板在弹道冲击及冲击后压缩(compression after impact,CAI)性能方面的表现,结果表明,玄武岩纤维显著提升了混杂层合板的能量吸收能力。采用C扫描、电子显微镜和扫描电镜分析了材料的损伤机制,揭示了材料性能提升的内在机理。另一方面,混杂层合板的初始压缩强度随玄武岩纤维含量的增加而下降。在混杂层合板的能量吸收能力增强与初始压缩强度下降的共同作用下,CAI测试中受损层合板的残余压缩强度呈局部波动趋势。研究结果可为轻量化、高抗冲击复合材料的结构设计提供指导。
基金The National Basic Research Program of China (973Pro-gram)(No.2006CB705505)
文摘In order to describe the compressibility of traffic flows and determine the compression factors, the Mach number of gas dynamics is introduced, and the concept and the formula of the compression factor are obtained. According to the concept of the compression factor and its differential equation, a stop-wave model is built. The theoretical value and the observed one are obtained by the survey data in Changchun city. The relative error between the two values is 20. 3%. The accuracy is improved 39% compared with the result from the traditional stop-wave model. The results show that the traffic flow is compressible, and the methods of research on gas compressibility is also applicable to the traffic flow. The stop-wave model obtained by the compression factor can better describe the phenomenon of the stop wave at a signalized intersection when compared with the traditional stop-wave model.
