层间短纤维增韧复合材料层板横向裂纹扩展的试验研究

TEST STUDY ON TRANSVERSE MATRIX CRACK GROWTH OF COMPOSITE LAMINATES WITH INTERLAMINAR SHORT FIBERS

对于Zylon短纤维层间增韧层板和普通碳纤维树脂复合材料层板,利用自制小型弯曲试验器和90o铺层缺口试件进行四点弯曲和三点弯曲试验,研究和比较两种层板中基体横向裂纹的发生与扩展规律。结果表明,两种层板基体横向开裂应力基本相同,而裂纹扩展有明显差别。普通层板基体裂纹贯穿90o铺层、不稳定扩展,平均速度约为17.7m/s;而层间增韧层板发生短纤维桥联,使基体横向裂纹的不稳定扩展停止,因而层间短纤维可显著提高基体横向裂纹扩展阻力。试验应用表明,小型弯曲试验器是有效的,尤其便于在光学显微镜下进行实时细观观测。

Using a purpose-made small bonding test set, four and three point bonding tests were conducted for two kinds of notch specimens of 90° layup carboon-fibor/resin composite laminates, with and without interlaminar short Zylon fibers, to investigate and compare their matrix cracking behavior. The experimental results show that in the two cases the transverse matrix cracking initiates under an almost same stress, but the crack growth is quite different. The matrix crack growth of the plain laminates is unstable and ran through the whole thickness of specimens in the average speed of 17.7 m/s. However, in the specimens with interlaminar short fibers, the fiber bridging makes the initially tmstable growth of the matrix crack stopped and obviously increases the resistance to matrix cracking. The mini-type test set is efficient and, in particular, convenient to real-time micro-observation under optical microscope.