Low-velocity drop-weight impact experiments on individual and multiple Cyclotetramethylene tetranitramine (HMX) energetic particles were performed using a modified drop-weight machine equipped with high-speed photogra...Low-velocity drop-weight impact experiments on individual and multiple Cyclotetramethylene tetranitramine (HMX) energetic particles were performed using a modified drop-weight machine equipped with high-speed photography components. Multiple particles experienced more severe burning reactions than an individual particle. Comparisons between impacted salt and HMX particle show that jetting in HMX is mainly due to the motion of fragmented particles driven by gaseous reaction products. Velocity of jetting, flame propagation, and area expansion were measured via image processing, making it possible to quantify the chemical reaction or mechanical deformation violence at different stages.展开更多
The advancement of rail transportation necessitates energy absorption structures that not only ensure safety but also optimize space utilization,a critical yet often overlooked aspect in existing designs.This study pr...The advancement of rail transportation necessitates energy absorption structures that not only ensure safety but also optimize space utilization,a critical yet often overlooked aspect in existing designs.This study presents a compact energy absorption structure(CE)that integrates the advantages of cutting rings and thin-walled tube modules,offering a solution with the high space utilization and the superior crashworthiness.Through theoretical modeling and experimental validation using a drop-weight test system,we analyzed the dynamic response and energy absorption characteristics of the CE.Comparative analysis with existing structures,namely the cutting shear rings(CSR)energy absorption structure and thin-walled tube structure(TW),revealed that the CE significantly improves specific energy absorption(SEA)by 102.76%and 61.54%,respectively,and optimizes crush force efficiency(CFE)by increasing 8.23%and 5.49%compared to CSR and TW.The innovative design of the CE,featuring deformation gradient and delay response strategies,showcases its potential for practical application in engineering,advancing the field of crashworthiness engineering.展开更多
The mechanical behaviour of Titanium-based Fiber Metal Laminates(FMLs)reinforced with Kevlar,Jute and the novel woven(Kevlar+Jute)fiber mat were evaluated through tensile,flexural,Charpy impact,and drop-weight tests.T...The mechanical behaviour of Titanium-based Fiber Metal Laminates(FMLs)reinforced with Kevlar,Jute and the novel woven(Kevlar+Jute)fiber mat were evaluated through tensile,flexural,Charpy impact,and drop-weight tests.The FMLs were fabricated with various stacking configurations(2/1,3/2,4/3,and 5/4)to examine their influence on mechanical properties.Kevlar-reinforced laminates consistently demonstrated superior tensile and flexural strengths,with the highest tensile strength of 772 MPa observed in the 3/2 configuration,attributed to Kevlar's excellent load-bearing capacity.Jute-reinforced laminates exhibited lower performance due to poor bonding and early delamination,while the FMLs reinforced with woven(Kevlar+Jute)fiber mat achieved a balance between mechanical strength and cost-effectiveness by attaining a tensile strength of 718 MPa in the 3/2 configuration.Impact energy absorption results revealed that Kevlar-reinforced FMLs provided the highest energy absorption under Charpy tests,reaching 13.5 J in the 3/2 configuration.The 4/3 configu ration exhibited superior resistance under drop-weight impacts,absorbing 104.7 J of energy.Failure analysis using SEM revealed key mechanisms such as fiber debonding,delamination,and fiber pull-out,with increased severity observed in laminates with a higher number of fiber-epoxy layers,especially in the 5/4 configuration.This study highlights the potential of Kevlar-Jute hybrid fiber-reinforced FMLs for applications requiring high mechanical performance and impact resistance.Future research should explore advanced surface treatments and the environmental durability of these laminates for aerospace and automotive applications.展开更多
基金supported by the National Natural Science Foundation of China (Grants 11572045 and 11472051)the Defense Industrial Technology Development Program (Grant B1520132004)the General Project of the CAEP Safety and Ammunition Center (Grant RMC2015B03)
文摘Low-velocity drop-weight impact experiments on individual and multiple Cyclotetramethylene tetranitramine (HMX) energetic particles were performed using a modified drop-weight machine equipped with high-speed photography components. Multiple particles experienced more severe burning reactions than an individual particle. Comparisons between impacted salt and HMX particle show that jetting in HMX is mainly due to the motion of fragmented particles driven by gaseous reaction products. Velocity of jetting, flame propagation, and area expansion were measured via image processing, making it possible to quantify the chemical reaction or mechanical deformation violence at different stages.
基金Project(12272414)supported by the National Natural Science Foundation of ChinaProject(2023RC3045)supported by the Science and Technology Innovation Plan of Hunan Province,China。
文摘The advancement of rail transportation necessitates energy absorption structures that not only ensure safety but also optimize space utilization,a critical yet often overlooked aspect in existing designs.This study presents a compact energy absorption structure(CE)that integrates the advantages of cutting rings and thin-walled tube modules,offering a solution with the high space utilization and the superior crashworthiness.Through theoretical modeling and experimental validation using a drop-weight test system,we analyzed the dynamic response and energy absorption characteristics of the CE.Comparative analysis with existing structures,namely the cutting shear rings(CSR)energy absorption structure and thin-walled tube structure(TW),revealed that the CE significantly improves specific energy absorption(SEA)by 102.76%and 61.54%,respectively,and optimizes crush force efficiency(CFE)by increasing 8.23%and 5.49%compared to CSR and TW.The innovative design of the CE,featuring deformation gradient and delay response strategies,showcases its potential for practical application in engineering,advancing the field of crashworthiness engineering.
基金the aid of Research and Development Fund-Seed Money provided by Vel Tech Rangarajan Dr.Sagunthala R&D Institute of Science and Technology。
文摘The mechanical behaviour of Titanium-based Fiber Metal Laminates(FMLs)reinforced with Kevlar,Jute and the novel woven(Kevlar+Jute)fiber mat were evaluated through tensile,flexural,Charpy impact,and drop-weight tests.The FMLs were fabricated with various stacking configurations(2/1,3/2,4/3,and 5/4)to examine their influence on mechanical properties.Kevlar-reinforced laminates consistently demonstrated superior tensile and flexural strengths,with the highest tensile strength of 772 MPa observed in the 3/2 configuration,attributed to Kevlar's excellent load-bearing capacity.Jute-reinforced laminates exhibited lower performance due to poor bonding and early delamination,while the FMLs reinforced with woven(Kevlar+Jute)fiber mat achieved a balance between mechanical strength and cost-effectiveness by attaining a tensile strength of 718 MPa in the 3/2 configuration.Impact energy absorption results revealed that Kevlar-reinforced FMLs provided the highest energy absorption under Charpy tests,reaching 13.5 J in the 3/2 configuration.The 4/3 configu ration exhibited superior resistance under drop-weight impacts,absorbing 104.7 J of energy.Failure analysis using SEM revealed key mechanisms such as fiber debonding,delamination,and fiber pull-out,with increased severity observed in laminates with a higher number of fiber-epoxy layers,especially in the 5/4 configuration.This study highlights the potential of Kevlar-Jute hybrid fiber-reinforced FMLs for applications requiring high mechanical performance and impact resistance.Future research should explore advanced surface treatments and the environmental durability of these laminates for aerospace and automotive applications.
