Stress transfer of single fiber/microdroplet tensile test studied by micro-Raman spectroscopy

When a fiber/microdroplet tensile specimen solidifies, a spindle-like microdroplet would form naturally, due to the balance role of surface forces at the gas/liquid interface. The stress transfer at the interface between the single aramid fiber and the epoxy microdroplet was studied by micro-Raman spectroscopy under different strain levels. From the fiber entered end to the inner of microdroplet, the fiber axial stress as well as the interfacial shear stress decreases gradually, because the bulk volume of the microdroplet changes along the fiber. Moreover, there exists a larger fiber axial stress and a lesser interfacial shear stress along the fiber and lower stress transfer efficiency under a large strain. Maximum shear stress inside the microdroplet usually locates at 3.5–6.5 fiber radius distances from the interfacial edge.