POSITIVE AND NEGATIVE PRESSURE SENSITIVITIES OF CARBON FIBER-REINFORCEDCEMENT-MATRIX COMPOSITES AND THEIR MECHANISM
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摘要: 对碳纤维水泥基复合材料的压敏特性进行了实验研究。结果发现, 在含水量不同的情况下, 碳纤维水泥基复合材料分别具有正、负两种压敏特性。含水量较高时, 碳纤维水泥基材料的电阻相对变化率随应力的增大而增大, 随应力的减小而减小, 表现出正压敏性。而含水量较低时, 电阻相对变化率随应力的增大而单调减小,随应力的减小而单调增大, 表现出负压敏性, 进而提出了一种双效应机理, 并对这一物理现象进行了合理解释。
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关键词:
- 碳纤维水泥基复合材料 /
- 压敏性 /
- 含水量 /
- 隧穿效应 /
- 电容效应
Abstract: The pressure sensitive behaviors of carbon fiber-reinforced cement-mat rix composites with differentmoisture content s were studied. The result s show that the relative change in resistanceΔR/ R0 varies with the moisture content of the composites. With higher moisture content , the relative change in resistanceΔR/ R0 increases withthe increase of compressive st ress , and decreases during unloading , demonst rating the positive pressure sensitivity.However , when the moisture content is reduced af ter specimens’being oven-dried , the relative change in resistanceΔR/ R0 decreases monotonically with the increase of compressive st ress , and increases monotonically during unloading , showing the negative pressure sensitivity. The mechanism for these phenomena is discussed. -
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