<p>The paper studies the damage initiation and evolution of composite honeycomb sandwich structures with inserts subjected to pull-out and shear loadings by a combination of experimental and numerical methods. The mechanical responses, including load-displacement curves, were obtained through pull-out tests, and detailed damage analysis was conducted using 3D X-ray scanning technology. A damage model based on macro-failure theory and cohesive behavior was used to predict the mechanical behavior of the composite face sheets, and an equivalent thick orthotropic plate model based on sandwich panel theory was employed to model the honeycomb core. The experimental and numerical results show good agreement, demonstrating that the established refined finite element model of the honeycomb sandwich insert structure possesses high-precision damage prediction capability. Simulation results reveal that under pull-out loading, the damage in odd layers is primarily concentrated in the upper-right sector of the region, while even layers exhibit damage in the lower-left sector. Fsurthermore, the honeycomb core develops damage along a 45° direction driven by a buckling-shear-slip mechanism. Under shear loading, the strain concentration in the insert region leads to local bending of the honeycomb walls, and the damage expands from the region toward the free edges along the transverse direction until the final collapse.</p>