This paper focuses on the interface failure in metal/GFRP laminates on account of the high-velocity impact phenomenon by a hemispherical projectile.The study considers three laminates in which the failure inside the 8...This paper focuses on the interface failure in metal/GFRP laminates on account of the high-velocity impact phenomenon by a hemispherical projectile.The study considers three laminates in which the failure inside the 8-layer 0/90 GFRP laminate is compared with the other two laminates that include metal layers in their layup configuration.The metal layers were placed on the top and bottom on one type of laminates while in the other additional metal layers are placed symmetrically inside the layup as well.They were subjected to high-velocity impact by a hemispherical projectile at different energy levels and the idea is not to perforate the laminate configuration instead to account for the damage incurred in these laminates and the role of metal layers in providing resistance to damage within these laminates.The study utilizes experimental findings and proposes a rate-dependent Finite Element(FE)model consisting of the Hashin-Puck failure scheme for composite and the Johnson-Cook damage model for metal layers.The results of the model satisfactorily agree with their experimental counterparts and provide valuable insight into the damage resistance inside the laminates.It has been observed that the 8-layer GFRP laminate was good in terms of elastic recovery and prevention of propagation of damage inside the laminates only,till the impact energy was lower.For higher impact energy,they show poor damage resistance as the fiber failure is triggered in them.However,laminates with metal layers are shown to protect the laminate by dissipating energy in the delamination of metal/GFRP interface,shear failure of the metal layer,and on account of metal plasticity.The study further shows that the throughthickness compressive stresses were responsible for the failure of laminates and also triggering the delamination in them.A damage energy study was performed to investigate the amount of energy dissipating in various failure modes like delamination,matrix cracking,fiber failure,etc。展开更多
The aim of the research work was to numerically investigate the residual stresses induced between the layers of fiber metal laminate (FML) cylinder (glass/epoxy reinforced aluminum laminates) under buckling hydrostati...The aim of the research work was to numerically investigate the residual stresses induced between the layers of fiber metal laminate (FML) cylinder (glass/epoxy reinforced aluminum laminates) under buckling hydrostatic loading. For the analysis of buckling behavior of FML cylinders, various fiber orientations such as 0/90°, 60/30°, ±45° and ±55° and different FRP thickness of 1, 2, and 3 mm were considered. The aluminum cylinder of inner diameter 80 mm, length 800 mm and wall thickness 1 mm was modeled with SHELL281 element type and a total of 1033 elements were used for computing the induced residual stresses between the layers. The results show that magnitude of residual stresses between the layers decreased along the thickness from outer layer towards the inner layer in sine wave form. The maximum residual Von-Mises stress was at inner aluminum layer while the maximum residual radial stress was at the outermost layer of FML cylinder due to the inward pressure. Among all types of FML cylinder 0/90° fiber oriented FML cylinder exhibited the least radial stress and a maximum Von-Mises stress along the FRP thickness.展开更多
纤维金属层板(Fiber metal laminates,FMLs)具有优异的综合力学性能,被广泛应用于航空航天和轨道交通等领域。FMLs在应用过程中会受到不同程度的冲击,相对于高速冲击而言,低速冲击产生的损伤大多肉眼不易觉察,但仍会造成裂纹、分层等不...纤维金属层板(Fiber metal laminates,FMLs)具有优异的综合力学性能,被广泛应用于航空航天和轨道交通等领域。FMLs在应用过程中会受到不同程度的冲击,相对于高速冲击而言,低速冲击产生的损伤大多肉眼不易觉察,但仍会造成裂纹、分层等不可逆的损伤,带来安全隐患。因此,对于FMLs低速冲击损伤的研究不容忽视。本文探讨分析了FMLs的低速冲击损伤机制、影响因素及提高抗低速冲击性能的方法,总结论述了低速冲击性能的评价方法、损伤检测技术及从数值模拟研究现状,最后提出了未来FMLs低速冲击的研究热点及发展方向。展开更多
Fiber Metal Laminates(FMLs),as high-performance composite materials,demonstrate exceptional potential in a wide range of applications,such as aeronautical and astronautical industries.However,the traditional cured FML...Fiber Metal Laminates(FMLs),as high-performance composite materials,demonstrate exceptional potential in a wide range of applications,such as aeronautical and astronautical industries.However,the traditional cured FMLs possess complex interlayer stresses and low forming limits,restricting further promotion and application of FMLs.Low-constraint FMLs exhibit a lower forming resistance and better formability due to no curing during the forming process;however,the formation mechanism and response are not clear.This paper presents the Forming Limit Diagram(FLD)of low-constraint GLARE(glass fiber reinforced aluminum laminates)based on the forming limit test,and compares it with the conventionally cured laminates to evaluate the differences in the forming limit.In addition,combined with the analysis of failure mechanism and micro-deformation mechanism of specimens,the influence of different temperatures(20–80℃)and forming states(width)on the deformation performance of laminates is further explored.The results reveal that the forming limit curve of low-constraint laminates shifts up with the increase of temperature,the forming limit initially increases with the increase of width,then followed by a gradual decrease,and the maximum principal strain of low-constraint laminates is increased by 29% at 80℃ compared to 20℃.The cured laminate has a principal strain range of 0–0.02,while the low-constraint laminates have a principal strain range of 0.03–0.14.Compared with cured laminates,low-constraint laminates possess a higher forming limit due to the improvement in deformable degree between layers by resin flow and fiber slippage,which enhances their formability.This study is expected to serve as a reference for establishing forming limit criteria and optimizing forming schemes for low-constraint laminates.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
文摘This paper focuses on the interface failure in metal/GFRP laminates on account of the high-velocity impact phenomenon by a hemispherical projectile.The study considers three laminates in which the failure inside the 8-layer 0/90 GFRP laminate is compared with the other two laminates that include metal layers in their layup configuration.The metal layers were placed on the top and bottom on one type of laminates while in the other additional metal layers are placed symmetrically inside the layup as well.They were subjected to high-velocity impact by a hemispherical projectile at different energy levels and the idea is not to perforate the laminate configuration instead to account for the damage incurred in these laminates and the role of metal layers in providing resistance to damage within these laminates.The study utilizes experimental findings and proposes a rate-dependent Finite Element(FE)model consisting of the Hashin-Puck failure scheme for composite and the Johnson-Cook damage model for metal layers.The results of the model satisfactorily agree with their experimental counterparts and provide valuable insight into the damage resistance inside the laminates.It has been observed that the 8-layer GFRP laminate was good in terms of elastic recovery and prevention of propagation of damage inside the laminates only,till the impact energy was lower.For higher impact energy,they show poor damage resistance as the fiber failure is triggered in them.However,laminates with metal layers are shown to protect the laminate by dissipating energy in the delamination of metal/GFRP interface,shear failure of the metal layer,and on account of metal plasticity.The study further shows that the throughthickness compressive stresses were responsible for the failure of laminates and also triggering the delamination in them.A damage energy study was performed to investigate the amount of energy dissipating in various failure modes like delamination,matrix cracking,fiber failure,etc。
文摘The aim of the research work was to numerically investigate the residual stresses induced between the layers of fiber metal laminate (FML) cylinder (glass/epoxy reinforced aluminum laminates) under buckling hydrostatic loading. For the analysis of buckling behavior of FML cylinders, various fiber orientations such as 0/90°, 60/30°, ±45° and ±55° and different FRP thickness of 1, 2, and 3 mm were considered. The aluminum cylinder of inner diameter 80 mm, length 800 mm and wall thickness 1 mm was modeled with SHELL281 element type and a total of 1033 elements were used for computing the induced residual stresses between the layers. The results show that magnitude of residual stresses between the layers decreased along the thickness from outer layer towards the inner layer in sine wave form. The maximum residual Von-Mises stress was at inner aluminum layer while the maximum residual radial stress was at the outermost layer of FML cylinder due to the inward pressure. Among all types of FML cylinder 0/90° fiber oriented FML cylinder exhibited the least radial stress and a maximum Von-Mises stress along the FRP thickness.
文摘纤维金属层板(Fiber metal laminates,FMLs)具有优异的综合力学性能,被广泛应用于航空航天和轨道交通等领域。FMLs在应用过程中会受到不同程度的冲击,相对于高速冲击而言,低速冲击产生的损伤大多肉眼不易觉察,但仍会造成裂纹、分层等不可逆的损伤,带来安全隐患。因此,对于FMLs低速冲击损伤的研究不容忽视。本文探讨分析了FMLs的低速冲击损伤机制、影响因素及提高抗低速冲击性能的方法,总结论述了低速冲击性能的评价方法、损伤检测技术及从数值模拟研究现状,最后提出了未来FMLs低速冲击的研究热点及发展方向。
基金supported by the National Natural Science Fund of China(Nos.52005153,12227801,32300666,12072005,U23A2607)the Tianjin"Project+Team"Key Training Program,China(No.XC202052)+4 种基金the Key Program of Research and Development of Hebei Province,China(Nos.202030507040009,23311812D)the Natural Science Foundation of Hebei Province,China(No.E2023202183)the Project of High-Level Team Construction Introduction of Hebei Province,China(No.244A7620D)the Research Cooperation Project of Universities Stationed in Hebei Province and Shijiazhuang City,China(No.241080114A)Hebei Province Military-Civilian Integration Science and Technology Innovation Project,China(No.SJMYF2022X15)。
文摘Fiber Metal Laminates(FMLs),as high-performance composite materials,demonstrate exceptional potential in a wide range of applications,such as aeronautical and astronautical industries.However,the traditional cured FMLs possess complex interlayer stresses and low forming limits,restricting further promotion and application of FMLs.Low-constraint FMLs exhibit a lower forming resistance and better formability due to no curing during the forming process;however,the formation mechanism and response are not clear.This paper presents the Forming Limit Diagram(FLD)of low-constraint GLARE(glass fiber reinforced aluminum laminates)based on the forming limit test,and compares it with the conventionally cured laminates to evaluate the differences in the forming limit.In addition,combined with the analysis of failure mechanism and micro-deformation mechanism of specimens,the influence of different temperatures(20–80℃)and forming states(width)on the deformation performance of laminates is further explored.The results reveal that the forming limit curve of low-constraint laminates shifts up with the increase of temperature,the forming limit initially increases with the increase of width,then followed by a gradual decrease,and the maximum principal strain of low-constraint laminates is increased by 29% at 80℃ compared to 20℃.The cured laminate has a principal strain range of 0–0.02,while the low-constraint laminates have a principal strain range of 0.03–0.14.Compared with cured laminates,low-constraint laminates possess a higher forming limit due to the improvement in deformable degree between layers by resin flow and fiber slippage,which enhances their formability.This study is expected to serve as a reference for establishing forming limit criteria and optimizing forming schemes for low-constraint laminates.
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.
