Mohamed KHARRAT
,
Maher DAMMAK
,
Amine CHARFI
材料科学技术（英文）
Fibre-matrix interface is known to have contribution to the mechanical performance of fibre-reinforced composite by its potential for load transfer between the fibre and the matrix. Such load transfer is of great importance in dentistry when a post is used for fixing a ceramic crown on the tooth. In this study, a pull-out test was carried out to analyse the interfacial properties of a steel fibre embedded in a polyester and epoxy matrices. It was found that the fibre-matrix interface is debonded on the whole embedded length when the fibre stress reached the debonding stress. Then, the fibre stress fell down to the initial extraction stress required to pulling out the debonded fibre from the matrix. Both debonding stress and initial extraction stress initiated a linear increase with the implantation length after the debonding stress reached horizontal asymptotes. To analyse the fibre-matrix load transfer before debonding, an analytical shear-lag model was adopted to in this test conditions. Fitting the experimental results with the analytical model provided the interfacial shear strength. By considering the Coulomb friction at the fibre-matrix interface during the fibre extraction process, an analytical model which considers Poisson's effects on both fibre and matrix, was developed. In this model, knowledge of the initial extraction stress of the fibre provides the residual normal stress at the fibre-matrix interface.
关键词:
Fibre
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null
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null
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王伟
,
纪高宁
,
朱晓光
,
左小彪
,
孙福瑞
宇航材料工艺
doi:10.3969/j.issn.1007-2330.2016.05.015
采用改进设计的像框试验对Nomex蜂窝夹层结构的面内剪切性能进行了表征测试与研究.试验结果表明,在像框的持续性剪切载荷作用下,夹层结构首先发生了板-芯界面脱粘,继而蒙皮在竖直方向上形成了巨大的鼓包和皱褶.随着剪切载荷的增加,夹层结构最终发生了横向的断裂.多次试验结果所得的低于3％的离散率也预示出面内剪切像框试验的有效性和准确性.此外,试样和夹具之间的固定程度是影响面内剪切像框试验的关键因素.仅采用螺钉进行固定的试样测试时,螺钉受拉力的移动直接导致了夹层结构边缘破坏,然而样件本身所受像框的面内剪切载荷有限,试验无效.
关键词:
面内剪切
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像框试验
,
Nomex蜂窝夹层结构
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复合材料
,
脱粘
