The elasto-plastic buckling and postbuckling of fiber metal laminates （FML） are studied in this research. Considering the geometric nonlinearity of the structure and the elasto- plastic deformation of the metal laye...The elasto-plastic buckling and postbuckling of fiber metal laminates （FML） are studied in this research. Considering the geometric nonlinearity of the structure and the elasto- plastic deformation of the metal layers, the incremental Von Karman geometric relation of the FML with initial deflection is established. Moreover, an incremental elasto-plastic constitutive relation adopting the mixed hardening rule is introduced to depict the stress-strain relationship of the metal layers. Subsequently, the incremental nonlinear governing equations of the FML subjected to in-plane compressive loads are derived, and the whole problem is solved by the iterative method according to the finite difference method. In numerical examples, the effects of the initial deflection, the loading state, and the geometric parameters on the elasto-plastic buckling and postbuckling of FML are investigated, respectively.展开更多
Through theoretical analysis and finite element simulation,the low-velocity impact of rectangular foam-filled fiber metal laminate(FML)tubes is studied in this paper.According to the rigid-plastic material approximati...Through theoretical analysis and finite element simulation,the low-velocity impact of rectangular foam-filled fiber metal laminate(FML)tubes is studied in this paper.According to the rigid-plastic material approximation with modifications,simple analytical solutions are obtained for the dynamic response of rectangular foam-filled FML tubes.The numerical calculations for low-velocity impact of rectangular foam-filled FML tubes are conducted.The accuracy of analytical solutions and numerical results is verified by each other.Finally,the effects of the metal volume fraction of FMLs,the number of the metal layers in FMLs,and the foam strength on the dynamic response of foam-filled tubes are discussed through the analytical model in details.It is shown that the force increases with the increase in the metal volume fraction in FMLs,the number of the metal layers in FML,and the foam strength for the given deflection.展开更多
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
The elasto-plastic postbuckling of fiber metal laminated beams with delamination and the energy release rate along the delamination front are discussed in this paper. Considering geometrical nonlinearity, thermal envi...The elasto-plastic postbuckling of fiber metal laminated beams with delamination and the energy release rate along the delamination front are discussed in this paper. Considering geometrical nonlinearity, thermal environment and geometrical initial imperfection, the incremental nonlinear equilibrium equations of delaminated fiber metal laminated beams are established, which are solved using the differential quadrature method and iterative method. Based on these, according to the J-integral theory, the elasto-plastic energy release rate is studied. The effects of some important parameters on the elasto-plastic postbuckling behavior and energy release rate of the aramid reinforced aluminum laminated beams are discussed in details.展开更多
It is known that fiber metal laminates （FML） as one of hybrid materials with thin metal sheets and fiber/epoxy layers have the characteristics of the excellent damage tolerance, fatigue and impact properties with a ...It is known that fiber metal laminates （FML） as one of hybrid materials with thin metal sheets and fiber/epoxy layers have the characteristics of the excellent damage tolerance, fatigue and impact properties with a relatively low density. Therefore, the mechanical components using FML can contribute the enhanced safety level of the sound construction toward the whole body. In this study, the impact performance of carbon reinforced aluminum laminates （CARAL） is investigated by experiments and numerical simulations. Drop weight tests are carried out with the weight of 4.7 kg at the speed of 1 and 2 m/s, respectively. Dynamic non-linear transient analyses are also accomplished using a finite element analysis software, ABAQUS. The experiment results and numerical results are compared with impact load-time histories. Also, energy-time histories are applied to investigate the impact performance of CARAL.展开更多
基金supported by the National Natural Science Foundation of China(No.11272117)
文摘The elasto-plastic buckling and postbuckling of fiber metal laminates （FML） are studied in this research. Considering the geometric nonlinearity of the structure and the elasto- plastic deformation of the metal layers, the incremental Von Karman geometric relation of the FML with initial deflection is established. Moreover, an incremental elasto-plastic constitutive relation adopting the mixed hardening rule is introduced to depict the stress-strain relationship of the metal layers. Subsequently, the incremental nonlinear governing equations of the FML subjected to in-plane compressive loads are derived, and the whole problem is solved by the iterative method according to the finite difference method. In numerical examples, the effects of the initial deflection, the loading state, and the geometric parameters on the elasto-plastic buckling and postbuckling of FML are investigated, respectively.
基金the National Natural Science Foundation of China(Nos.11872291 and11972281)the Jiangsu Key Laboratory of Engineering Mechanics,Southeast University+2 种基金the Fundamental Research Funds for the Central Universities(No.LEM21B01)the Key Laboratory of Impact and Safety Engineering(Ningbo University),Ministry of Education(No.cj202002)the Natural Science Basic Research Plan in Shaanxi Province of China(No.2020JM-034)。
文摘Through theoretical analysis and finite element simulation,the low-velocity impact of rectangular foam-filled fiber metal laminate(FML)tubes is studied in this paper.According to the rigid-plastic material approximation with modifications,simple analytical solutions are obtained for the dynamic response of rectangular foam-filled FML tubes.The numerical calculations for low-velocity impact of rectangular foam-filled FML tubes are conducted.The accuracy of analytical solutions and numerical results is verified by each other.Finally,the effects of the metal volume fraction of FMLs,the number of the metal layers in FMLs,and the foam strength on the dynamic response of foam-filled tubes are discussed through the analytical model in details.It is shown that the force increases with the increase in the metal volume fraction in FMLs,the number of the metal layers in FML,and the foam strength for the given deflection.
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Project supported by the National Natural Science Foundation of China(No.11272117)
文摘The elasto-plastic postbuckling of fiber metal laminated beams with delamination and the energy release rate along the delamination front are discussed in this paper. Considering geometrical nonlinearity, thermal environment and geometrical initial imperfection, the incremental nonlinear equilibrium equations of delaminated fiber metal laminated beams are established, which are solved using the differential quadrature method and iterative method. Based on these, according to the J-integral theory, the elasto-plastic energy release rate is studied. The effects of some important parameters on the elasto-plastic postbuckling behavior and energy release rate of the aramid reinforced aluminum laminated beams are discussed in details.
基金supported by a grant-in-aid for the Na-tional Core Research Center Program from the Ministry of Education Science & Technology and the Korea Science & Engineering Foundation (No. R15-2006-022-01001-0)support by the Korea Science and Engineering Foundation (KOSEF) NRL Program grant funded by the Korea government (MEST) (No. R0A-2008-000-20017-0)
文摘It is known that fiber metal laminates （FML） as one of hybrid materials with thin metal sheets and fiber/epoxy layers have the characteristics of the excellent damage tolerance, fatigue and impact properties with a relatively low density. Therefore, the mechanical components using FML can contribute the enhanced safety level of the sound construction toward the whole body. In this study, the impact performance of carbon reinforced aluminum laminates （CARAL） is investigated by experiments and numerical simulations. Drop weight tests are carried out with the weight of 4.7 kg at the speed of 1 and 2 m/s, respectively. Dynamic non-linear transient analyses are also accomplished using a finite element analysis software, ABAQUS. The experiment results and numerical results are compared with impact load-time histories. Also, energy-time histories are applied to investigate the impact performance of CARAL.
