Aiming at addressing the issues of unclear dynamic response mechanisms and insufficient quantification of temperature coupling effects in building structures under long-duration blast loads,this study investigates typ...Aiming at addressing the issues of unclear dynamic response mechanisms and insufficient quantification of temperature coupling effects in building structures under long-duration blast loads,this study investigates typical composite beam-slab structures through integrated blast shock tube experiments and multiscale numerical simulations using Voronoi-coupled Finite-Discrete Element Method(VoroFDEM).The research systematically reveals the dynamic response mechanisms and damage evolution patterns of composite beam-slab structures subjected to prolonged blast loading.An environmenttemperature-coupled P-I curve damage assessment system is established,and a rapid evaluation method based on image crack characteristics is proposed,achieving innovative transition from traditional mechanical indicators to intelligent recognition paradigms.Results demonstrate that composite beam-slab structures exhibit three-phase failure modes:elastic vibration,plastic hinge formation,and global collapse.Numerical simulations identify the brittle-to-ductile transition temperature threshold at-10℃,and establish a temperature-dependent piecewise function-based P-I curve prediction model,whose overpressure asymptote displays nonlinear temperature sensitivity within-50-30℃.A novel dual-mode evaluation methodology integrating Voro-FDEM numerical simulations with image-based damage feature recognition is developed,enabling quantitative mapping between crack area and destruction levels.These findings provide theoretical foundations and technical pathways for rapid blast damage assessment and protective engineering design.展开更多
Calculating the parameters of the ground shock induced by an underground explosion is a complex energy coupling problem.It is difficult to establish a unified ground shock coupling law from limited test data.This pape...Calculating the parameters of the ground shock induced by an underground explosion is a complex energy coupling problem.It is difficult to establish a unified ground shock coupling law from limited test data.This paper summarizes the research results obtained at home and abroad and systematically analyzes the coupling mechanism of craters formed by an underground explosion and the ground shock.The differences between the concepts of"closed-explosion critical depth"and"equivalent closed-explosion critical depth"are clearly explained.The spreading of the ground shock energy is attributed to the explosive expansion of the air cavity,revealing a linear relationship between the volume of the cavity region(or the volume of the crack region)and the ground shock energy associated with the underground explosion.The proportionality factor is related to the mechanical properties of the medium and is independent of the magnitude of the explosion equivalent.Based on this,a theoretical calculation formula and conversion method for the ground shock coupling coefficient were established.Explosion tests were conducted in clay and Plexiglass under varying burial depths.The test results were consistent with the theoretically calculated results.Our study provides a theoretical basis for the design of explosion-resistant structures in underground engineering.展开更多
基金supported by Open Research Fund of State Key Laboratory of Target Vulnerability Assessment,Defense Engineering Institute,AMS,PLA(Grant No.YSX2024KFPG002)。
文摘Aiming at addressing the issues of unclear dynamic response mechanisms and insufficient quantification of temperature coupling effects in building structures under long-duration blast loads,this study investigates typical composite beam-slab structures through integrated blast shock tube experiments and multiscale numerical simulations using Voronoi-coupled Finite-Discrete Element Method(VoroFDEM).The research systematically reveals the dynamic response mechanisms and damage evolution patterns of composite beam-slab structures subjected to prolonged blast loading.An environmenttemperature-coupled P-I curve damage assessment system is established,and a rapid evaluation method based on image crack characteristics is proposed,achieving innovative transition from traditional mechanical indicators to intelligent recognition paradigms.Results demonstrate that composite beam-slab structures exhibit three-phase failure modes:elastic vibration,plastic hinge formation,and global collapse.Numerical simulations identify the brittle-to-ductile transition temperature threshold at-10℃,and establish a temperature-dependent piecewise function-based P-I curve prediction model,whose overpressure asymptote displays nonlinear temperature sensitivity within-50-30℃.A novel dual-mode evaluation methodology integrating Voro-FDEM numerical simulations with image-based damage feature recognition is developed,enabling quantitative mapping between crack area and destruction levels.These findings provide theoretical foundations and technical pathways for rapid blast damage assessment and protective engineering design.
基金funded by the National Natural Science Foundation of China(Grant No.52279120).
文摘Calculating the parameters of the ground shock induced by an underground explosion is a complex energy coupling problem.It is difficult to establish a unified ground shock coupling law from limited test data.This paper summarizes the research results obtained at home and abroad and systematically analyzes the coupling mechanism of craters formed by an underground explosion and the ground shock.The differences between the concepts of"closed-explosion critical depth"and"equivalent closed-explosion critical depth"are clearly explained.The spreading of the ground shock energy is attributed to the explosive expansion of the air cavity,revealing a linear relationship between the volume of the cavity region(or the volume of the crack region)and the ground shock energy associated with the underground explosion.The proportionality factor is related to the mechanical properties of the medium and is independent of the magnitude of the explosion equivalent.Based on this,a theoretical calculation formula and conversion method for the ground shock coupling coefficient were established.Explosion tests were conducted in clay and Plexiglass under varying burial depths.The test results were consistent with the theoretically calculated results.Our study provides a theoretical basis for the design of explosion-resistant structures in underground engineering.
