湿热环境对CCF800/环氧挖补板拉压性能的影响

As the aircrafts after scarf repair may experience hygrothermal environment during its service, the effect of hygrothermal environment on tensile and compressive properties of scarf-repaired laminates was studied in this paper. The tensile and compressive properties of composite CCF800/epoxy scarf-repaired laminates in four hygrothermal environments were firstly tested. Then, corresponding finite element models of hygrothermal stress were established to explore structural hygrothermal stress distribution in different environments. Finally, the tensile and compressive property analysis models of scarf-repaired laminates in the hygrothermal environment were established to explore the effect of the hygrothermal environment on the mechanical properties of the scarf-repaired laminates. The experimental results show that the hygrothermal environment reduces the compressive bearing capacity of scarf-repaired laminates, but improves their tensile bearing capacity, which is inconsistent with the common sense. Through experimental observation and mechanism analysis, it was found that the fiber misalignment in CCF800/epoxy laminates is the main reason that the tensile properties of the scarf-repaired laminates do not decrease but rise in hygrothermal environment. Therefore, with hygrothermal environment considered, the problem of fiber misalignment needs to be paid special attention to in the production of CCF800 fiber composite materials.