Photoelastic study of the mechanic behaviour of orthotropic composite plates subjected to impact

The objectives of the work presented in this paper are to establish an experimental method for the investigation of the impact behaviour of composites and to study the mechanical response of orthotropic composite plates subjected to transverse impact loadings below the damage threshold. The experimental method is based on the photoelastic stress coating technique. The experimental set-up incorporates a pneumatic impact test device and an optical set-up distinguished by ultrashort-term light sources to achieve a high temporal resolution. The investigations of various carbon-fibre/epoxy laminate plates give a comprehensive insight into the mechanical events, due to impact loadings, in unmodified plates and plates with a local increase and a local decrease in stiffness due to structural elements, i.e., stiffeners and openings