Fiber-metal laminates(FMLs)consist of three layers of aluminum alloy 2024-T3 and two layers of glass/epoxy prepreg,and it(it means FMLs)is laminated by Al alloy and fiber alternatively.Fatigue crack growth rates in no...Fiber-metal laminates(FMLs)consist of three layers of aluminum alloy 2024-T3 and two layers of glass/epoxy prepreg,and it(it means FMLs)is laminated by Al alloy and fiber alternatively.Fatigue crack growth rates in notched fiber-metal laminates under constant amplitude fatigue loading were studied experimentally and numerically and were compared with them in monolithic 2024-T3 Al alloy plates.It is shown that the fatigue life of FMLs is about 17 times longer than monolithic 2024-T3 Al alloy plate;and crack growth rates in FMLs panels remain constant mostly even when the crack is long,unlike in the monolithic 2024-T3 Al alloy plates.The formula to calculate bridge stress profiles of FMLs was derived based on the fracture theory.A program by Matlab was developed to calculate the distribution of bridge stress in FMLs,and then fatigue growth lives were obtained.Finite element models of FMLs were built and meshed finely to analyze the stress distributions.Both results were compared with the experimental results.They agree well with each other.展开更多
Structural impact tests were first presented to cover typical fibre metal laminates (FMLs) subjected a low velocity projectile impact,which produced the corresponding load-displacement traces and deformation/failure m...Structural impact tests were first presented to cover typical fibre metal laminates (FMLs) subjected a low velocity projectile impact,which produced the corresponding load-displacement traces and deformation/failure modes for the validation of numerical models.Finite element (FE) models were then developed to simulate the impact behaviour of FMLs tested.The aluminium (alloy grade 2024-0) layer was modelled as an isotropic elasto-plastic material up to the on-set of post failure stage,followed by shear failure and tensile failure to simulate its failure mechanisms.The glass fibre laminate (woven glass-fibre reinforced composite) layer was modelled as an orthotropic material up to its on-set of damage,followed by damage initiation and evolution using the Hashin criterion.The damage initiation was controlled by failure tensile and compressive stresses within the lamina plane which were primarily determined by tests.The damage evolution was controlled by tensile/compressive fracture energies combined with both fibre and matrix.The FE models developed for the 2/1,3/2 and 4/3 FMLs plates made with 4-ply and 8-ply glass fibre laminate cores were validated against the corresponding experimental results.Good correlation was obtained in terms of load-displacement traces,deformation and failure modes.The validated models were ready to be used to undertake parametric studies to cover FMLs plates made with various stack sequences and composite cores.展开更多
基金supported by Chengdu Aircraft Design&Research Institutethe National Natural Science Foundation of China(Grant No.11002111)the Scholarship of Study Abroad Council
文摘Fiber-metal laminates(FMLs)consist of three layers of aluminum alloy 2024-T3 and two layers of glass/epoxy prepreg,and it(it means FMLs)is laminated by Al alloy and fiber alternatively.Fatigue crack growth rates in notched fiber-metal laminates under constant amplitude fatigue loading were studied experimentally and numerically and were compared with them in monolithic 2024-T3 Al alloy plates.It is shown that the fatigue life of FMLs is about 17 times longer than monolithic 2024-T3 Al alloy plate;and crack growth rates in FMLs panels remain constant mostly even when the crack is long,unlike in the monolithic 2024-T3 Al alloy plates.The formula to calculate bridge stress profiles of FMLs was derived based on the fracture theory.A program by Matlab was developed to calculate the distribution of bridge stress in FMLs,and then fatigue growth lives were obtained.Finite element models of FMLs were built and meshed finely to analyze the stress distributions.Both results were compared with the experimental results.They agree well with each other.
基金supported by a PhD studentship of the University of Liverpoolsupported by the Engineering and Physical Sciences Research Council (EPSRC)
文摘Structural impact tests were first presented to cover typical fibre metal laminates (FMLs) subjected a low velocity projectile impact,which produced the corresponding load-displacement traces and deformation/failure modes for the validation of numerical models.Finite element (FE) models were then developed to simulate the impact behaviour of FMLs tested.The aluminium (alloy grade 2024-0) layer was modelled as an isotropic elasto-plastic material up to the on-set of post failure stage,followed by shear failure and tensile failure to simulate its failure mechanisms.The glass fibre laminate (woven glass-fibre reinforced composite) layer was modelled as an orthotropic material up to its on-set of damage,followed by damage initiation and evolution using the Hashin criterion.The damage initiation was controlled by failure tensile and compressive stresses within the lamina plane which were primarily determined by tests.The damage evolution was controlled by tensile/compressive fracture energies combined with both fibre and matrix.The FE models developed for the 2/1,3/2 and 4/3 FMLs plates made with 4-ply and 8-ply glass fibre laminate cores were validated against the corresponding experimental results.Good correlation was obtained in terms of load-displacement traces,deformation and failure modes.The validated models were ready to be used to undertake parametric studies to cover FMLs plates made with various stack sequences and composite cores.
