Sandwich panels with carbon fiber fabric/epoxy resin face-sheet and aluminum foam core have a potential application value in the engineering field. To study the bending mechanical properties of the reinforced sandwich structure, three-point bending test was conducted by using WDW-T100 electronic universal tensile testing machine. The relation between load and displacement of the aluminum foam sandwich was obtained. Deformations and failure modes of the specimens were recorded. Scanning electron microscopy was used to observe the failure mechanism. Results showed that when aluminum foam was reinforced by carbon fiber fabric as face-sheet, its flexural load-carrying capacity and energy absorption ability improved significantly. Foam core density and number of carbon fiber plies had serious impacts on the peak load value and energy absorption value of the composite structure. It was suggested that aluminum foam core sandwich structure with low foam core density of 0.49 g/cm³and 5 plies of carbon fiber fabric had the highest energy absorption ability and medium load-carrying ability. Failure modes analysis showed that shear failure leaded to the final failure of sandwich panels with medium peak load and interface de-bonding leaded to the final failure of sandwich panels with high peak load.

The aluminum foam sandwich (AFS), which perfectly combines the excellent merits of an aluminum foam core and face sheet materials, has extensive and reliable applications in many fields, such as aerospace, military equipment, transportation, and so on. Adhesive bonding is one of the most widely used methods to produce AFS due to its general applicability, simple process, and low cost, however, the bonding interface is known as the weak link and may cause a serious accident. To overcome the shortcomings of a bonded AFS interface, short carbon fiber as a reinforcement phase was introduced to epoxy resin to reinforce the interface adhesion strength of AFS. Single lap shear tests and three-point bending tests were conducted to study the mechanical behavior of the reinforced interface and AFS, respectively. The failure mechanism was studied through a macro- and microanalysis. The result showed that after the reinforcement of carbon fiber, the tangential shear strength of the interface increased by 73.65%. The effective displacement of AFS prepared by the reinforced epoxy resin is 125.95% more than the AFS prepared by the unreinforced epoxy resin. The flexure behavior of the reinforced AFS can be compared with AFS made through a metallurgical method. Three categories of reinforcement mechanisms were discovered: (a) the pull off and pull mechanism: when the modified carbon fiber performed as the bridge, the bonding strength improved because of the pull off and pull out of fibers; (b) adhesion effect: the carbon fiber gathered in the hole edge resulted in epoxy resins being gathered in there too, which increased the effective bonding area of the interface; (c) mechanical self-locking effect: the carbon fiber enhanced the adhesive filling performance of aluminum foam holes, which improved the mechanical self-locking effect of the bonding interface.