Deformation mechanism investigation for epoxy by insitu eletrical and mechanics coupling measurement

The carbon nanotube modified composite is fabricated and experimentally measured by the electrical resistance of specimen during compressive loading to obtain the composite resistivity-strain curve, in the hope of probing into the deformation mechanism at peak stress. The deformation mechanism would change at the peak stress due to the sharp increase of specimen volume resistivity, which is also further confirmed by a series of specifically-designed experiments. Then the mechanism is proposed that while loading to peak stress, some cross-linked sites start to break, then induces the abrupt increase of material resistivity. And then the molecular chain units freed from the broken sites can form the molecular chain segments which facilitate to initiate the strain-softening deformation. The mechanism is also further confirmed by analysis on the gap stress, peak strain and CNT conductive mechanism. Such a mechanism bridges and modifies the previous consensus regarding the natures of below and post peak stress deformation of epoxy.