Experimental study on the strain self-sensing properties of nano carbon black modified resin based CFRP bars

In order to explore the influence of nano carbon black content on the piezoresistive effect of resin based CFRP bars, 2%, 4%, 6%, 8%, 10% nano carbon black modified resin were used as matrix, and the roller extrusion process was adopted to prepare CFRP bars. The initial resistivity, the response of resistance change and the relationship between sensitivity change and strain under static tensile test were compared and analyzed. The results show that the strain sensitivity of CFRP bars can be significantly improved, and the discreteness of test data can be reduced by adding uniformly dispersed carbon black into the resin matrix. The optimum content of carbon black is 6%, the sensitivity is 25.4 in the strain range of 0 ∼ 1.2%, and the linear relationship between resistance change rate and strain is satisfied, and the determinable coefficient is 0.985. When the content of carbon black is more than 6%, the effect of modification on the sensing properties of CFRP bars is not obvious.