Experimental investigation of the fiber bundle shielding effect on the dynamic matrix crack using optical caustic method

The fiber bundle shielding effect on the dynamic matrix cracking in fiber reinforced composite under dynamic loading was investigated using an optical caustics method. First, edge cracked epoxy beams, with a symmetrically positioned fiber bundle ahead of the crack tip, were preformed to simulate matrix crack shielding by the fiber bundle in fiber reinforced composites. Then, the effect of fiber bundle width on the dynamic matrix crack propagation behavior was analyzed using the caustics method, where the caustic spot shape, the dynamic stress intensity factor and crack propagation velocity were obtained to characterize the shielding effect of the fiber bundle. Finally, the shielding effect of a tilted fiber bundle with an angle of 30°on the dynamic matrix crack was analyzed using the optical caustics method, where the different fiber bundle width would cause different failure modes and failure mechanisms.