To strengthen Specific Energy-Absorption (SEA) behavior of Sandwich Composite Structure (SCS),a kind of light-weight vertical stiffener is proposed for the corrugated core.The vertical stiffener,embedded in the corrugated core,can not only absorb part of energy but also simultaneously enhance Energy-Absorption (EA) of other components.The Hashin damage model considering the shear stress and ductile damage model is adopted to predict the failure of carbon fiber face-sheets and aluminum-core,respectively.The perfect bonding is modeled for interfaces between the face-sheet and core due to little realistic debonding.The finite element model is verified by available data of conventional SCS.To obtain more design ideas,several stiffeners with different thicknesses,numbers,and positions are investigated.From the predicted results,both the flexural load and deformation of SCS correlate well with experimental results.It is highlighted that the SCSs with different vertical stiffeners exhibit 9.74％ 58.48％ higher SEA than the SCS without stiffener.The complex reinforcement mechanisms are extensively revealed by underlying coupling EA and deformation mechanisms.Structural parameter analysis shows that the thickness and number have significant effects on the flexural behavior and SEA of reinforced SCS.