A new strategy for preparing web‐reinforced foam sandwich composites with excellent mechanical properties

Abstract Web‐reinforced foam sandwich composite structures have garnered significant attention for their ability to improve Z‐direction strength (strength along thickness) and interfacial mechanical properties. However, the complexity of their manufacturing process has hindered large‐scale applications. The thermal expansion molding process (TEMP) addresses these engineering challenges by generating expansion pressure from the inside out, enabling the formation of intricate web‐reinforced sandwich composite structures. In this study, a thermal expansion epoxy foam expanded 2–10 times under 110–150°C conditions. By coordinating the foam and Carbon fiber reinforced polymer (CFRP) prepreg system, we successfully established the match among expansion pressure, time, temperature, and viscosity for the composites prepared using TEMP. Based on the mechanical properties and microstructure of the composite materials, we selected an expandable foam that expanded four times at 135°C, resulting in various specifications of corrugated plate‐reinforced foam sandwich composite structures. When comparing the newly designed structures to pure foam sandwich structures, we observed a significant improvement in mechanical performance: the compression strength increased from 4.81 to 10.59 MPa, while the specific energy absorption rose from 2285.63 to 3864.63 J/kg with a corrugated plate width of 20 mm. This study establishes a foundation for integrating the TEMP to create complex reinforced sandwich composite structures, paving the way for future applications in engineering. Highlights A coordinated regulation method of TEMP technology was proposed. The match of parameters was obtained to control TEMP technology. The TEMP technology has more advantages in forming sandwich composites. The compression properties of corrugated plate were improved.