碳纤维毡/环氧树脂复合材料的力阻效应∗

摘要

The piezoresistive responses of the composites fabricated by short-cut carbon fiber mat and epoxy res-in were studied by uniaxial tension tests.Positive piezoresistive effect of this composite was found in the test. The gauge factor for single-lamina carbon fiber mat/epoxy resin composite is as high as 13.9,but the resistance for this composite is observed to be decreased gradually.More stable piezoresistivity was attained in laminated composite and the gauge factors were observed to decrease with the increase of the number of the laminas.The gauge factor for 5-lamina carbon fiber mat/epoxy resin composite is 5.7.The improvement in stability and the decrease in gauge factor for the laminated composite are due to the solid conductive network of this composite. The laminated carbon fiber mat/epoxy resin composites were used as smart layers on the beam surfaces,and based on their piezoresistivities,the structural deformation monitoring upon cyclic load and the damage detec-ting upon monotonous load were conducted.%以短切碳纤维毡和环氧树脂为原材料制成复合材料,考察了该材料在单向拉伸载荷下的力阻响应.实验结果表明,该材料具有正力阻效应(拉应变引起材料的电阻增大).其中,单层碳纤维毡/环氧树脂复合材料的力阻灵敏度可达13．9,但在加载过程中其电阻表现出逐渐衰减趋势；多层碳纤维毡/环氧树脂复合材料的力阻性能更为稳定,但随着层数的增加灵敏度逐渐降低,5层复合材料的力阻灵敏度下降到5．7.多层复合材料的立体导电网络是其稳定性提升和灵敏度下降的主要原因.将碳纤维毡/环氧树脂多层复合材料敷设在梁结构表面形成智能表层,利用其力阻性能实现了梁结构在循环载荷下的变形监测以及在单调载荷作用下损伤监测.