This study investigates the bending failure mechanisms of composite curved beams through experimental testing and numerical simulation. After a series of improvements to the ASTM standards, multi-angle laminate specimens with a stacking sequence of [45/0/-45/90] \(_\text {2s}\) were subjected to four-point bending loads, with strain distributions monitored using digital image correlation (DIC). Experimental observations revealed failure cracks propagating along interlaminar regions, exhibiting "delamination migration" behavior. DIC results highlighted a strong correlation between crack initiation and maximum shear strain concentration. A progressive damage model (PDM) incorporating the 3D-Hashin criterion was developed to simulate the failure process. The simulations identified matrix-fiber shear and interlaminar tensile failures as primary contributors, while delamination migration was attributed to matrix tensile failure within \(\pm \) \(45^\circ \) and \(90^\circ \) plies. This study establishes shear failure as a dominant failure mechanism, emphasizing the need for enhanced interlaminar shear resistance in the design of composite curved beams.
