湿热环境对T800S/M21碳纤维复合材料基体主导力学性能的影响研究

Research on the influence of hygro-thermal effects on matrix-dominated mechanical properties of T800S/M21 CFRP composites

以T800S/M21碳纤维复合材料为研究对象,在三种吸湿调控与两种试验温度的湿热环境组合下,开展90°拉伸、±45°拉伸以及Ⅰ型与Ⅱ型层间断裂等基体主导力学性能影响试验。研究了湿热环境对基体拉伸及面内剪切模量与强度的影响,获得了湿热环境对层间性能G_(Ⅰc)与G_(Ⅱc)的影响。基于±45°拉伸与裂纹观察试验,获得了剪切刚度退化与厚度面裂纹数量演化规律,并分析了吸湿调控对引起剪切刚度退化的损伤机理影响。结果表明:湿热环境对T800S/M21复合材料基体主导的拉伸与剪切性能产生显著的折减影响,也对层间性能产生退化影响。湿热环境对面内剪切非线性特征产生一定弱化影响,吸湿加速了宏观裂纹产生与剪切刚度退化进程,导致宏观裂纹产生了比微观裂纹更加显著的刚度折减贡献。

This work studies the hygro-thermal effects on matrix-dominated mechanical properties of T800S/M21 CFRP laminates.Experimental tests are performed on 90°and ±45° laminate test coupons to investigate the hygro-thermal effects on matrix dominated tension and shear mechanical behaviors.Laminate interface properties under fracture mode Ⅰ and mode Ⅱ considering different hygro-thermal conditions are evaluated by DCB and ENF tests.Based on ±45° tension test,crack density on specimen edge is measured to support the analysis of shear modulus degradation and crack density evolution under different moisture absorption conditions.In conclusion:Hygro-thermal conditions show significant effects on matrix dominated in-plane and interface properties.The nonlinear response of in-plane shear is strongly dependent on hygro-thermal conditions.Test results show that moisture absorption accelerates the crack density evolution and shear modulus degradation,and moisture content plays an important role in the contribution of crack density to the shear modulus reduction.