This study focuses on investigating the behavior of a thermoplastic matrix composite (Carbon Fiber-LMPAEK) under a bearing strength determination test. The specimens were subjected to a double-shear-bolted joint configuration tensile test, and the propagation of damage was monitored using extensometers. The research employs a technique that involves inelastic modelling and considers discrepancies in layer interfaces to better understand bearing damage propagation. In this context, cohesive modelling was utilized in all composite layers, and the Hashin damage propagation law was applied. The double-shear-bolted joint configuration chosen for the test revealed critical insights into the bearing strength determination of the Carbon Fiber-LMPAEK thermoplastic matrix composite. This comprehensive approach, combining inelastic modelling and considerations for layer interfaces, provided a nuanced understanding of the material’s response to bearing forces. The results of the study demonstrated that all specimens exhibited the desired type of bearing failure, characterized by severe delamination around the hole. Interestingly, the thermoplastic matrix composite showcased enhanced bearing properties compared to traditional thermoset materials. This observation underscores the potential advantages of thermoplastic composites in applications requiring robust bearing strength. One noteworthy aspect highlighted by the study is the inadequacy of current aerospace standards in prescribing the accumulation of bearing damage in thermoplastic composites. The research underscores the need for a more strategic modelling approach, particularly in cohesive modelling, to accurately capture the behavior of thermoplastic matrix composites under bearing forces. In summary, this investigation not only provides valuable insights into the bearing strength of Carbon Fiber-LMPAEK thermoplastic matrix composites, but also emphasizes the necessity for refining aerospace standards to address the specific characteristics and failure modes of these advanced materials.

This paper presents the end-to-end multidisciplinary development and flight-test assessment of a Class I fixed-wing mini unmanned aerial vehicle (UAV) designed for surveillance and reconnaissance missions. The development process progresses from mission and system-level requirements through conceptual, preliminary, and detailed design, followed by prototype fabrication and experimental flight testing. Conceptual design establishes aircraft mass, wing and power loading, aerodynamic configuration, wing geometry, airfoil selection, mass distribution, and initial stability characteristics. The preliminary and detailed stages progressively increase analysis fidelity through assessments of aerodynamics, structures, aeroelasticity, propulsion, stability and control, performance, and thermal management. High-fidelity Computational Fluid Dynamics (CFD) is employed for aerodynamic char-acterization and load prediction, while Finite-Element (FE) and aeroelastic models are used to assess strength, stiffness, static and dynamic aeroelastic behavior. The aircraft configuration incorporates a V-tail, electric pusher propulsion, composite structural components, integrated control surfaces, wingtip devices, and dedicated cooling arrangements. A representative 3D-printed flight-test article retaining the principal aerodynamic architecture was subsequently evaluated in climb, straight-and-level flight, sustained turns, and low-speed operation. The vehicle exhibited stable and predictable handling throughout the tested envelope. Flight-derived aerodynamic characteristics showed close agreement with the detailed-design CFD database, with drag-coefficient deviations remaining below approximately 3% in straight-and-level flight and within approximately 1.5% during climb. Larger discrepancies, reaching approximately 16%, were observed during sustained turns, highlighting the increased uncertainty associated with maneuvering flight and with drag values inferred using the propulsion model. Overall, the study demonstrates a traceable progressive-fidelity methodology for advancing a mini-UAV from requirements and conceptual sizing to multidisciplinary verification and prototype-level flight assessment.