Static And Dynamic Axial Crushing Of Aluminum Foam Filled Circular Aluminum Alloy Tube

In recent years,terrorist attacks and natural disasters have occurred frequently.In order to improve the safety performance of building structures under extreme accidental loads such as explosions and impacts,the impact protection of building structures has become a current research hotspot.Among them,the composite material member formed by the combination of the metal pipe and the foam material has superior energy consumption performance,and has been widely used in the fields of aerospace,automobile and the like.Based on the above background,this paper proposed to combine aluminum foam with the 6082-T6 circular aluminum alloy tube to form composite components.Its response characteristics,failure mechanism and energy dissipation performance under axial compression and axial impact load are tested and numerically simulated.The main research work includes the following parts:(1)Study on constitutive model and failure criteria of 6082-T6 aluminum alloy15 uniaxial tensile tests of 6082-T6 aluminum alloy were carried out to obtain material parameters such as elastic modulus,elongation and tensile strength of aluminum alloys with different wall thicknesses.It was found that the stress-strain curve of aluminum alloy was in good agreement with jackson-Cook model.The CockcroftLatham ductile fracture criterion was selected as the method to determine the material failure,and the critical failure plastic strain energy Wcr of aluminum alloys with different wall thicknesses was obtained by the material tensile tests and finite element simulation results.The results show that Cockcroft-Latham ductile fracture criterion can simulate the failure behavior of 6082-T6 aluminum alloy at room temperature.(2)Study on axial crushing performance of aluminum foam filled circular aluminum alloy tube20 aluminum alloy hollow tube and aluminum foam filled circular aluminum alloy tubes were designed and fabricated,and the axial compression tests were carried out to obtain the deformation and load-displacement curves of the specimens during the entire axial compression process.The deformation process,failure mode and energy dissipation characteristics of different specimens under axial load are compared and analyzed.The three failure modes of the specimens under axial load were summarized and the causes were analyzed.Using the ANSYS/LS-DYNA finite element platform,a refined finite element model of aluminum foam filled circular aluminum alloy tube under axial compression load was established.The model considered factors such as failure judgment basis of aluminum alloy materials,mesh size and contact settings.The accuracy of the finite element model was verified by comparing load-displacement curve and deformation mode of the test and finite element simulation results.Through the axial compression numerical model,the expanded parameter analysis under axial compression load was carried out,and the influence of the pipe diameter,wall thickness and height on the failure mode and energy dissipation capacity of the component was obtained.(3)Study on axial impact performance of aluminum foam filled circular aluminum alloy tubeBased on the ANSYS/LS-DYNA finite element platform,a refined finite element model of aluminum foam filled circular aluminum alloy tube under axial impact load was established,and the strain rate effect of 6082-T6 aluminum alloy was considered.The hammer head and counterweight were reasonably simplified,and the model was set up with reasonable contact.By comparing with the load-displacement curve and deformation mode of the axial impact test of polyurethane foam-filled round steel tubes in the existing literature,the applicability of the finite element model is verified.The failure modes and energy dissipation properties of aluminum foam filled circular aluminum alloy tube under axial impact load were studied,and the response characteristics,failure modes and energy dissipation properties of aluminum alloy hollow tube and aluminum foam filled circular aluminum alloy tube were compared and analyzed under axial compression load and axial impact load.Based on the finite element model,the expanded parameter analysis under the axial impact load was carried out,and the influence law of pipe diameter,wall thickness,height,mass of impingement and impact velocity of the specimen on the impact failure mode and energy dissipation property was obtained.(4)Multi-objective optimization of energy dissipation performance of aluminum foam filled circular aluminum alloy tubeBased on the Pareto method,a multi-objective optimization design was carried out for a total of 4 working conditions of aluminum alloy empty pipe members and aluminum foam filled members under axial load and axial impact load.The three parameters of outer diameter D,wall thickness T and height H were selected as design variables,the first peak compression force PCL and the first average compression force MCL in the folding unit were selected as the optimization goals.The test design points were selected for the four working conditions through the test design method ULH.The corresponding specimens of the test design points were subjected to finite element simulation to obtain the peak compression force PCL and the average compression force MCL.The neural network method of the PCL and MCL under four working conditions was obtained through the Python platform using neural network methods.Finally,the non-dominated sorting genetic algorithm NSGA-II was used to solve the multi-objective optimization problem,and the parameter combination of the components under different working conditions was obtained.The optimal solution set provided a reference for the application of components in actual engineering.