Electrical resistance change of unidirectional CFRP due to applied load
Electrical resistance change of unidirectional CFRP due to applied load
复制标题
DOI：
10.1299/jsmea.47.357
复制
发表时间：
2004-07-01
期刊：
影响因子：
--
通讯作者：
Yoshida, J
中科院分区：
文献类型：
--
作者：
Todoroki, A;Yoshida, J
碳纤维增强塑料（CFRP）是由导电碳纤维和电绝缘树脂组成。利用单向碳纤维增强复合材料（CFRP）在纤维断裂和外加应变作用下的电阻变化，提出了一种自监测系统。压阻率是电阻随外加应变而变化。许多研究者已经报道了单向CFRP的压阻效应。然而，有很大的差异，在测得的压阻率，甚至在纤维方向在拉伸载荷：无论是正压阻率（电阻增加）和负压阻率（电阻减少）在拉伸试验期间报告。据报道，由于电接触不良导致的电极处的电阻变化是这种大差异的主要原因。因此，在本研究中，压阻的基本性能进行了测量与标本制成的单层和多层层压板使用四证明方法。在拉伸加载过程中，测量了纤维方向横向上的电阻变化的许多情况。还使用剪切试验研究了剪切载荷的影响。为了研究电极处不良电接触的影响，在不抛光样品表面的情况下制备电极，并进行拉伸试验，测量压阻率。试验结束后，对试样表面进行抛光。并使用相同的试样再次进行拉伸试验。结果表明，单层和多层试样的压阻系数均为正值，而负压阻系数的产生是由于电极间的电接触不良所致。
Carbon Fiber Reinforced Plastic (CFRP) is composed of electric conductive carbon fibers and electric insulator resin. Self-monitoring system has been reported utilizing electric resistance change of unidirectional CFRP due to fiber breakages and to applied strain. Piezoresistivity is electric resistance change with applied strain. Many researchers have already reported the piezoresistivity of unidirectional CFRP. There is, however, large discrepancy in the measured piezoresistivity even in the fiber direction during tensile loading: both positive piezoresistivity (electric resistance increase) and negative piezoresistivity (electric resistance decrease) are reported during tensile tests. Electric resistance change at electrodes due to poor electric contacts are reported to be a main cause of this large discrepancy. In the present study, therefore, basic properties of piezoresistivity were measured with specimens made from single-ply and multi-ply laminates using a four-prove method. Many cases of electric resistance changes in the fiber direction transverse direction were measured during tensile loading. Effect of shear loading was also investigated using a shear test. To investigate the effect of poor electric contact at the electrodes, electrodes were made without polishing specimen surface and a tensile test was performed with measuring piezoresistivity. After the test, the specimen surface was polished,. and a tensile test was performed again using the identical specimen. As a result, positive piezoresistivity was obtained for both single-ply and multi-ply specimens and negative piezoresistivity is confirmed that it was caused by the poor electric contact at electrodes.