Abstract
The measurement method on deformation and strain distribution at different length scales ranging from nm to few mm was investigated by in-situ FE-SEM observation. The composite material used was ultrahigh strength PAN-based (IM600) and ultrahigh modulus pitch-based (K13D) hybrid carbon fiber reinforced epoxy matrix composites. The multiscale pattern was fabricated onto the polished specimen surface by combining photolithography and electron beam lithography techniques. Digital images correlation method was applied to measure the multiscale deformation taking note of some interfaces such as the fiber/matrix interface and the laminates interface before and after loading. The localized plastic strain clearly formed around the interfaces at different length scales. In the present study, the results clearly demonstrated that the development of a multi-scale pattern is significant for measuring multi-scale deformation and strain localization to identify damage initiation and evolution at different scale lengths.
