| With the global industrialisation process and the promotion of green and low-carbon concepts,new energy vehicles are becoming increasingly demanding in terms of light weight.Carbon fibre composites(CFRP)-aluminium alloy materials combine the advantages of both CFRP and aluminium alloy to meet the lightweight requirements,but due to the different nature of the two materials,the connection is difficult.In order to achieve a high-strength connection between CFRP and aluminium alloy,this paper adopts co-curing to connect CFRP and aluminium alloy,studies the influence of aluminium alloy on the interface performance under different surface treatment methods,optimises the surface treatment process parameters and CFRP-aluminium alloy composite connection structure,establishes a reliable composite connection structure and ABAQUS simulation model of the main structure of the box under the new energy vehicle battery,and verifies the accuracy of the simulation model through experiments.The accuracy of the simulation model was verified through experiments.The main contents and results are as follows:(1)Optimisation of aluminium alloy surface treatment process parameters.The effects of laser treatment frequency,rate and line spacing parameters and plasma treatment time,distance and gas flow rate parameters on the roller peel strength of CFRP-aluminium alloy cocured joint samples were investigated respectively.When the aluminium alloy was treated with laser parameters of 10.763 k Hz,102.719 mm/s,0.115 mm and plasma parameters of 173.132 s,5.821 mm,597.383 L/h,the surface of the aluminium alloy was treated with both the reticulated crater shape of laser treatment and the ablation shape and surface activation effect of plasma treatment,which improved the surface roughness and surface energy,resulting in the highest peel strength of 113.02(N·mm)/mm,a 15.12-fold increase over the untreated sample of the aluminium alloy.(2)Ageing resistance of CFRP-aluminium alloy lap shear joints under different surface treatments.Based on the optimum parameters of the different surface treatments,lap shear joints were fabricated for ageing resistance studies.Under the experimental conditions of cold and thermal shock aging for 30 days,temperature-humidity coupling aging for 30 days and salt spray corrosion aging for 72 h,the failure strength of the joints decreased by 15.60%,16.35% and 21.83%,respectively,with the best ageing resistance.(3)The influence of CFRP-aluminium alloy composite joint structure and surface treatment on the performance of the main structure of the under-battery box.The composite joint structure was optimised based on the bending and tensile tests of the CFRP-aluminium alloy joints.Using ABAQUS software,a reliable model of the lower box body structure was established for compression simulation analysis based on the model parameters of the composite joint structure.The maximum compression load of the composite joint lower box body structure under optimised surface treatment using the vacuum bagging method was77.010 k N,with an error of 3.34% from the simulation results,representing a 73.98% increase in maximum load and a 71.83% increase in mass to strength over the welded lower box body structure. |
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