Mechanical and Impact Response of Adhesively Bonded <scp>ASA</scp> / <scp>PA12</scp> Sandwich Structures Produced by Fused Filament Fabrication

ABSTRACT Multi‐material polymer sandwich structures produced by fused filament fabrication (FFF) have attracted increasing interest for applications requiring tailored stiffness, toughness, and impact resistance. Despite growing use of adhesive bonding in additively manufactured assemblies, the combined influence of material arrangement and adhesive compliance on the mechanical response of FFF‐fabricated polymer sandwiches remains insufficiently understood. The present study aims to clarify how adhesive type and layer stacking sequence interact to govern the tensile and impact behavior of multi‐material sandwich structures manufactured from acrylonitrile styrene acrylate (ASA) and polyamide 12 (PA12). Three‐ply layered specimens with different ASA—PA12 stacking configurations were fabricated by FFF and subsequently bonded using two distinct adhesive systems, namely a cyanoacrylate‐based adhesive and a polyurethane‐based adhesive. Tensile tests and drop‐tower impact experiments were conducted to evaluate mechanical performance, damage evolution, and energy absorption characteristics. Cyanoacrylate bonding resulted in the highest tensile strength and modulus for the ASA + ASA + ASA configuration, reaching 40.28 MPa (Standard Deviation, SD: 0.24) and 1180.42 MPa (SD: 4.64), respectively, whereas the polyurethane‐bonded PA + PA + PA specimen showed the highest failure strain of 10.27% (SD: 0.33). In contrast, the cyanoacrylate‐bonded PA + PA + PA configuration exhibited the lowest tensile strength and failure strain, with 23.32 MPa (SD: 2.59) and 3.47% (SD: 0.53), respectively. Under impact loading, monolithic PA12 exhibited the highest break energy of 1.27 J, while polyurethane‐bonded multilayer specimens showed consistently higher break energy values (1.01–1.15 J) than their cyanoacrylate‐bonded counterparts (0.29–0.77 J). In addition, the specific absorbed energy of the ASA + ASA + ASA configuration increased from 0.13 kJ/kg with cyanoacrylate to 0.20 kJ/kg with polyurethane. These findings highlight the importance of interfacial design in multi‐material additive manufacturing and provide practical guidance for tailoring the mechanical and impact performance of FFF‐fabricated polymer sandwich structures.