Bo Liu

To support vehicle crash simulation in lightweight automotive design, this study develops high-precision constitutive and fracture models for a giga casting Mg-7Al-1.5La-1Zn magnesium alloy. Through mechanical testing and microstructural analysis, the plastic hardening, strain-rate strengthening, and ductile fracture behaviors are systematically investigated. A weighted mixed hardening model combining the saturation-type Hockett–Sherby and unsaturated Swift models is established. To overcome the limitations of the classical Johnson–Cook (J-C) model in capturing strain rate–plastic strain coupling, a modified dynamic increase factor incorporating equivalent plastic strain is proposed. Comparative fitting with the Cowper–Symonds model confirms that the modified J-C model better captures the twinning deformation mechanism under high strain rates and achieves higher accuracy. Among three fracture models Johnson–Cook (J-C), Modified Mohr-Coulomb(MMC), and Damage Initiation and Evolution Model (DIEM), the MMC model, which incorporates both stress triaxiality and Lode angle, shows the best predictive performance, with an average accuracy of 86.46% for fracture displacement across the full stress range. Microstructural characterization reveals grain refinement and dispersed Al₁₁La₃ precipitates that improve grain boundary properties. The established parameter set and calibration methods provide a reliable reference for material card calibration in crash simulation of giga casting magnesium alloy body structures.

The low-altitude economy represents an important facet of emerging productive forces, and flying cars serve as key vehicles driving its development. This paper proposes an aerodynamic design for the aerial vehicle module of split-type flying cars, which meets the functional requirements for vertical takeoff, climb, and cruising, and provides a reference solution for urban air mobility. A multidisciplinary constraint-based approach was employed to define the design requirements of the aerial vehicle module, ensuring its capability to operate in various complex environments. Through theoretical analysis and Computer-Aided Design (CAD) methods, key geometric, aerodynamic, and stability parameters were developed and evaluated. After finalizing the design concept of the aerial vehicle module, aerodynamic analysis was conducted, and aerodynamic coefficients were assessed using Computational Fluid Dynamics (CFD) simulations across angles of attack ranging from −5° to 20°. The results indicated that the aerial vehicle module achieved a maximum lift-to-drag ratio of 13.40 at an angle of attack of 2°, and entered a stall condition at 13°. The aerodynamic design enhances the module’s stability under various operating conditions, thereby improving handling performance. Overall, the aerial vehicle module demonstrates favorable aerodynamic characteristics during low-altitude flight and low-speed cruising, satisfying the design requirements and constraints.