Multifunctional behavior of composite beams incorporating hybridized carbon-based materials under cyclic loadings

Abstract The investigation was performed on the cyclic self-sensing behavior of reinforced composite beams produced with carbon fiber (CF) and carbon black (CB) in a hybridized form. Prior to the investigation, CFs and CBs were individually used in small-scale specimens at different ratios. The electrical properties were tailored by binary using of CFs and CBs for the improved self-sensing functionality. After evaluation of electrical and mechanical properties, self-sensing reinforced composite beams were produced with a span/effective depth ratio of 2.2. Repetitive loading and unloading cycles within elastic and plastic range were separately evaluated and applied for the developed composite beams. Beams were tested up to 30% and 70% of their ultimate flexural strength for the cyclic loadings within elastic and plastic range, respectively. Engineering properties and self-sensing assessments were simultaneously performed. Experimental findings revealed that developed composite beams provided a reversible piezoresistive behavior under plastic regime although it was partially possible under the elastic regime. Only beams coupled with hybrid carbon-based materials were able to repetitively self-sense damages between %30 and %70 of the total applied load. Carbon-based materials made a slight contribution to the engineering properties of beams as also validated by finite element analysis.