Mechanical Behavior And Failure Predictions Of Bismaleimide Resin Matrix Composite Laminates

Carbon fiber reinforced Bismaleimide(CF/BMI)resin matrix composites have excellent properties such as high strength,high stiffness,corrosion resistance,and good fatigue resistance,and are widely used in fields such as aerospace,rail transportation,shipbuilding,and sports equipment.In the actual production,use,and maintenance process of composites,they often experience external loads,so the prediction of damage to composite laminates and the repair technology after damage are important for extending the service life of composites and maintaining the strength of composite structures.This thesis proposes a Carbon fiber reinforced resin matrix composites damage prediction model that integrates the 3D Hashin damage criteria within layers,the B-K interlayer fracture energy evolution criteria,and the stiffness degradation model.The accuracy of the proposed damage prediction model is verified through a combined analysis method of finite element software ABAQUS simulation and experimental verification.Based on the proposed composites damage prediction model,research on the hole-cutting and patching technology for composite laminates is conducted.The main research work and conclusions are as follows:(1)According to GB/T 3354-2014 Oriented Polymer Matrix Composites Tensile Property Test Method,single-directional laminates with 0° and 90° orientations were designed and tested for longitudinal and transverse tensile strength and tensile modulus of the composite laminates used in this study:XT=1602.4MPa,E11=159.9GPa,YT=39.99MPa,E22=32.39GPa。(2)Multi-directional laminates with holes were analyzed by ABAQUS finite element simulation software for unidirectional tensile simulation,and a unidirectional tensile test of multi-directional laminates with holes was designed to verify the simulation.It was found that the simulation and experimental results were basically consistent.The main failure mode of the 0° laminate was carbon fiber tensile failure,while the main failure mode of the 45°,-45°,and 90° laminates was matrix tensile failure.The data error obtained from the simulation and experiment was within the allowable range,which verifies the accuracy of the proposed composites material damage prediction model.(3)Based on the proposed composites material damage prediction model,research on hole-cutting and patching of composite laminates was conducted from two perspectives:exploring the effect of different patch types and different strength adhesives on the repair rate.It was concluded that patch with additional laminates can effectively improve the repair rate of laminates,and using stronger adhesives to bond the base plate and patch can significantly improve the repair rate of laminates.