Fiber metal laminates (FMLs) are hybrid materials consisting of metals and fiber-reinforced composite materials. The characteristics of interfaces between metal layers and layers of composites directly determine the damage tolerance and impact resistance of FMLs. In this study, the effects of surface pre-treatment and adhesive quantity on the interface of FMLs were investigated. Aluminum substrates were treated with sandpaper and anodizing. The treated surface structure and joint shear strength were evaluated to analyze the bonding interface quality. The results show that the surface roughness, structure and thickness of the anodized films affect the interface characteristics and adhesion strength. A porous oxide layer was formed on the substrate surface after anodization, resulting in a better wetting surface than that of sanded. Moreover, statistical analysis of the surface structures reveals that the shear strength of phosphoric acid anodizing treatment was higher than other anodizing. With the increase in adhesive layers, the lap shear strength was markedly improved at the beginning but slowly increased thereafter. From the results, the surface pre-treatment and adhesive quantity could be optimized to improve the manufacturing process of FMLs.

Due to their mechanical load-bearing and functional wave transmission, adhesively bonded joints of carbon fiber–quartz fiber composites have been widely used in the new generation of stealth aviation equipment. However, the curing defects, caused by deviations between the process environment and the setting parameters, directly affect the service performance of the joint during the curing cycle. Therefore, the thermophysical parameter evolution of adhesive films was analyzed via dynamic DSC (differential scanning calorimeter), isothermal DSC and TGA (thermal gravimetric analyzer) tests. The various prefabricating defects within the adhesive layer were used to systematically simulate the impacts of void defects on the tensile properties, and orthogonal tests were designed to clarify the effects of the curing process parameters on the joints’ bonding performance. The results demonstrate that the J-116 B adhesive film starts to cure at a temperature of 160 °C and gradually forms a three-dimensional mesh-bearing structure. Furthermore, a bonding interface between the J-116 B adhesive film and the components to be connected is generated. When the curing temperature exceeds 200 °C, both the adhesive film and the resin matrix thermally degrade the molecular structure. The adhesive strength weakens with an increasing defect area ratio and number, remaining more sensitive to triangle, edge and penetration defects. By affecting the molecular structure of the adhesive film, the curing temperature has a significant impact on the bonding properties; when the curing degree is ensured, the curing pressure directly impacts the adhesive’s performance by influencing the morphology, number and distribution of voids. Conversely, the heating rate and heat preservation time have minimal effects on the bonding performance.

Fiber metal laminate (FML) is a kind of lightweight material that has garnered much attention in recent years due to its excellent properties under tensile, flexure, and impact conditions. However, little attention has been paid to the evolution of aluminum alloy during the FML forming process. In this paper, the effects of specimen thickness and the non-isothermal process on creep behavior of AA2024 aluminum alloy, which is generally used in FMLs, were systematically studied in terms of creep strain, mechanical properties, and microstructure. The results show that the microstructure and mechanical properties of the aluminum alloy layer are greatly affected by the creep age during the FML forming process, but the specimen thickness has little effect on the creep behavior under experimental conditions. During the non-isothermal process, the creep strain generated during the heating stage is about 40% of total strain. Compared with the isothermal process, the creep strain of the non-isothermal process increases by 20–40%, and the apparent activation energy Q_c is larger. According to the creep behavior of AA2024 aluminum alloy during the non-isothermal process, a creep constitutive model was established to accurately simulate the deformation of FMLs.

Carbon fiber-reinforced polymer (CFRP) composites are widely used in aerospace due to their excellent strength-to-weight ratio and tailorable properties. However, these properties critically depend on the CFRP curing cycle. The commonly adopted manufacturer-recommended curing cycle (MRCC), designed to accommodate the most conservative conditions, involves prolonged curing times and high energy consumption. To overcome these limitations, this study proposes an efficient and adaptable method to determine the optimal curing cycle. The effects of varying heating rates on resin dynamic and isothermal–exothermic behavior were characterized via reaction kinetics analysis using differential scanning calorimetry (DSC) and rheological measurements. The activation energy of the reaction system was substituted into the modified Sun–Gang model, and the parameters were estimated using a particle swarm optimization algorithm. Based on the curing kinetic behavior of the resin, CFRP compression molding process orthogonal experiments were conducted. A weighted scoring system incorporating strength, energy consumption, and cycle time enabled multidimensional evaluation of optimized solutions. Applying this curing cycle optimization method to a commercial epoxy resin increased efficiency by 247.22% and reduced energy consumption by 35.7% while meeting general product performance requirements. These results confirm the method’s reliability and its significance for improving production efficiency.

The epoxy-bonded joint between carbon-fiber-reinforced bismaleimide (CF-BMI) and quartz-fiber-reinforced bismaleimide (QF-BMI) composites can meet the structure–function integration requirements of next-generation aviation equipment, and the structural design of their bonding zones directly affects their service performance. Hence, in this study, the carbon-fiber-reinforced bismaleimide composite ZT7H/5429, the woven quartz-fiber-reinforced bismaleimide composite QW280/5429, and epoxy adhesive film J-116 were used as research materials to investigate the influence of the bonding area size on the mechanical properties, and this study proposes a novel design methodology combining radial basis function (RBF) neuron machine learning with the NSGA-II algorithm to enhance the mechanical properties of the bonded components. First, a finite element simulation model considering 3D hashin criteria and cohesion was established, and its accuracy was verified with experiments. Second, the RBF neuron model was trained using the finite element tensile strength and shear strength data from various adhesive layer parameter combinations. Then, the multi-objective parameter optimization of the surrogate model was accomplished through the NSGA-II algorithm. The research results demonstrate a high consistency between the finite element simulation results and experimental outcomes for the epoxy-bonded CF/QF-BMI composite joint. The stress distribution of the adhesive layers is similar under the different structural parameters of adhesive films, though the varying structural dimensions of the adhesive layers lead to distinct failure modes. The trained RBF neuron model controls the prediction error within 2.21%, accurately reflecting the service performance under various adhesive layer parameters. The optimized epoxy-bonded CF/QF-BMI composite joint exhibits 16.1% and 11.2% increases in the tensile strength and shear strength, respectively.