A Multi-scale Investigations On The Bonding Performance Of Adhesively Bonded Structure Of Plain Weave Composites

Plain weave composite material is woven from warp and weft fibers.Compared with unidirectional layup fiber reinforced composite material,the spatial structure of the fiber is more complicated,the mechanical properties can be designed more,and the mechanical properties are more excellent.Therefore,it has been widely favored in the fields of aerospace and vehicles.In order to more effectively apply the advantages of plain weave composites,it is necessary to study their mechanical properties and damage.In order to explore the mechanical properties and damage characteristics of the adhesvely bonded structure of plain weave composite material,this paper analyzes the plain weave composite laminate from three levels of microscopic,microscopic and macroscopic.First,based on the homogenization method,the equivalent material performance parameters of the microfiber bundle and the mesoscopic representative volume element(RVE)sub-cells are determined respectively.Corresponding damage criteria are introduced to simulate the progressive damage failure process of micro-fiber bundle RVE and mesoscale RVE model.The simulation results show that when the microscopic fiber bundle RVE is subjected to longitudinal tensile and longitudinal compression loads,the fibers bear the main load,and both the fibers and the matrix fail.When subjected to transverse tensile and transverse compression loads,the matrix bears the main load,only the matrix fails,and the fibers do not fail.When the mesoscale RVE is subjected to longitudinal tensile and longitudinal compression loads,the longitudinal fiber bundles bear the main load,and the matrix damage occurs before the fiber damage.Longitudinal fiber bundles damage occurs at the bend of the fiber bundle and extends from the edge to the middle.On the basis of this strategy,the mesoscale RVE subcell was equivalent to unidirectional composite laminates,and the initiation and evolution of intralaminar damage was simulated based on Hashin damage criterion and continuum damage mechanics(CDM)model,and the cohesive zone model(CZM)was used to simulate the damage of interlamination and adhesive film.The results show that the numerical curve of plain weave composite laminates is in good agreement with the experimental curve.Verified the validity of the multi-scale model.Finally,based on the macro-scale model,the effect of the bonding parameters on the bonding performance of the plain weave composite laminates adhesvely bonded structure was studied.Based on genetic algorithm,single-object multi-parameter optimization is performed on the known bonding parameters.Research results show: with the increase of the lap length,the ultimate failure load of adhesively bonded single-lap and double-lap joints rises gradually,the lap shear strength of adhesvely bonded structure decreases gradually.The failure modes gradually transform from the shear failure within adhesive film to the delamination failure within laminates.Under the same cementing parameters,double-lap adhesvely bonded structure connection is better than single-lap adhesvely bonded structure.The optimal lap length,the optimal lap width and the optimal thickness of the single-lap adhesvely bonded structure are 25 mm,20.64 mm and 0.24 mm respectively.The optimal lap length,the optimal lap width and thickness of the double-lap adhesvely bonded structure are 25 mm,26.92 mm and 0.24 mm respectively..