Fractographic relation between progressive failure and strain measurement techniques for recently developed configuration of carbon fiber/epoxy laminate

• DOI: 10.1016/j.polymertesting.2016.10.036
• Publication Date: 2016-11-19T07:01:45Z
• Authors: Jan Mayén; Arturo Abúndez; Enrique Alcudia; José Antonio Arel...; Jorge Colín; Isa Pereyra; Iván Puente-Lee
• Keywords: 02 engineering and technology; 0210 nano-technology

Abstract In this work, fracture mechanisms of a newly developed carbon fiber/epoxy laminate [+75/0/-75]s were assessed by scanning electron microscopy (SEM). The composite strain-stress curves were plotted with the displacement information simultaneously acquired from both a tensile testing machine crosshead and an extensometer. The strain-stress curve plotted with the displacement data from the machine test showed an average slope change from E1m = 22.783 GPa to E2m = 13.170 GPa on about 65% of the total strain before global failure, while strain-stress curves plotted with displacement data from the extensometer showed one single slope. While results reported in literature related to composite failure mechanisms, where some authors reported a slope change in strain-stress curves associated to progressive failure, experimental evidence in this work for strain-stress curves showed one single slope, indicating that such slope change is related to the strain measuring technique, and not to a progressive failure. The fracture surface was studied, and four main features were observed, which were related to failure mechanisms during the uniaxial test. The identified failure mechanisms occurred on a stage above 93% of the total strain before global failure.