缝合工艺对复合材料面内力学性能影响实验研究

EXPERIMENTAL STUDY ON THE EFFECT OF STITCHING PROCESS ON THE MECHANICAL PROPERTIES OF COMPOSITES

研究了不同缝合密度和不同缝线粗细对碳纤维八枚五飞经面缎缝合复合材料面内力学性能的影响,并结合显微镜观察测量因缝线植入导致面内纤维弯曲,分析了面内纤维弯曲与力学性能的相关性。结果表明,缝合对层板面内性能有一定的影响,随着缝合密度变密和缝线变粗,面内力学性能整体呈下降趋势,且降低幅度均增大。显微镜分析表明,用纤维弯曲幅度和角度表征面内纤维弯曲,面内纤维是影响缝合层板力学性能的主要因素。在相同缝线下,随着缝合密度变密,面内纤维弯曲幅度几乎不变,而弯曲角度先增大后减小,力学性能整体呈降低趋势;在相同缝合密度下,随着缝线变粗,纤维弯曲幅度和角度均增大,强度降低趋势与面内纤维弯曲幅度和角度有很强的相关性,其二次函数相关系数在0.89~0.97之间。

The effects of different stitch densities and different stitch thread thickness on the in-plane mechanical properties of carbon fiber eight-five-face satin-stitched composite materials were studied. The in-plane fiber waviness due to stitch thread implantation was measured by microscope observation,and the correlation between mechanical properties and in-plane fibers waviness was analyzed. The results show that the stitch has certain influence on the in-plane properties. As the stitch density becomes larger and the stitch thread becomes thicker,the in-plane mechanical properties show a decreasing trend and the decreasing range increases. Microscopic analysis shows that in-plane fiber waviness is characterized by the waviness amplitude and waviness angle in-plane,and the main factors that affect the mechanical properties of stitched laminates is in-plane fiber. Under the same stitch thread thickness,as the stitch density becomes dense,the waviness amplitude of the in-plane fiber is almost unchanged,and the waviness angle of the in-plane fiber increases first and then decreases,and the in-plane mechanical properties decrease as a whole. At the same stitch density,the waviness amplitude and angle of the in-plane fiber increased with the stitch thread thickness,and the decreasing trend of the strength had a strong correlation with the waviness amplitude and angle of the in-plane fiber,where the quadratic function correlation coefficient ranged from 0. 89 to 0. 97.