Current Issue : October-December Volume : 2026 Issue Number : 4 Articles : 5 Articles
Blade tip clearance (BTC) is a critical parameter for the thrust, fuel consumption, and operational safety of aero-engines, and its accurate monitorinfg is of significant engineering importance. Traditional eddy current sensors (ECS) in BTC measurement often employ wound coil structures, which suffer from issues such as poor consistency and limited geometric shapes, restricting further optimization of electromagnetic performance. This paper proposes a novel ECS based on ceramic-integrated printed coils. The ECS uses screen printing technology to directly print metal coils onto ceramic substrates and integrate them into a single unit, allowing the coils to be designed with high precision into any topology structure, with high consistency, structural stability, and high temperature tolerance. Performance studies indicate that the sensor can be manufactured with an accuracy of 0.2 mm or better, and the sensor with a line width and spacing of 0.2 mm performed the best in the test. Not only does it exhibit the best electromagnetic performance at room temperature, but it also shows an electromagnetic performance variation of less than 1% after a 24 h aging test at 800 ◦C. Additionally, it provides stable peak-to-peak and periodic responses to changes in BTC within the range of 0 to 600 rpm for the fan motor. This study provides a promising method for accurate and stable BTC measurement at high temperatures....
Sustained cislunar logistics operations, including recurring support of the Lunar Gateway at EML1 and EML2, impose demanding propulsion requirements, including high ΔV budgets, restart capability, and long-duration propellant storage, which conventional propulsion approaches struggle to meet efficiently at scale. This study presents a novel cislunar mission architecture based on nuclear thermal propulsion (NTP), operating at a specific impulse of 900 s with liquid hydrogen as propellant and a hydrazine Reaction Control System (RCS) for proximity and docking maneuvers. The architecture is evaluated analytically through sequential application of the Tsiolkovsky rocket equation across two mission scenarios: a direct logistics transfer to EML1 (Scenario A) and a two-burn Gateway staging transfer from EML1 to EML2 (Scenario B), using a launch mass of 9000 kg, a 5% ΔV margin, and deterministic ΔV values of 3164 m/s for LEO→EML1, 160 m/s for EML1→EML2, and 37.36 m/s for RCS operations. The proposed architecture achieves a total propellant mass below 3044 kg and a total delivered mass between 5956 kg and 6071 kg across both scenarios. These results establish NTP as a technically credible foundation for scalable and sustainable cislunar transportation, with broad implications for the development of a permanent lunar economy....
The radome of high-speed aircraft could suffer harsh thermal load during service, which affects the electromagnetic transmission performance of the radome. In this work, the influence mechanism and dominant factors governing the electromagnetic performance of the radome under a thermal environment are analyzed by combining the finite element method and multilevel fast multipole method. The finite element method is adopted to obtain the deformation of the radome. The multilevel fast multipole method is used to analyze the electromagnetic transmission performance of the deformed radome. The radome sample was fabricated, and the applicability of the analysis method was verified from both simulation and experimental perspectives. Furthermore, the electromagnetic performance of a streamlined radome under multiple operational conditions is analyzed. Results indicate that the deformation caused by thermal expansion has little influence on electromagnetic transmission performance. In contrast, temperature-dependent material possesses a huge effect on the electromagnetic transmission performance of the radome. To be more specific, electromagnetic transmission declines with increasing temperature because the permeability and permittivity parameters rise with the growth of temperature, and this rise means a more serious impedance imbalance and more thermal loss during the electromagnetic wave propagation process. Therefore, the influence of thermal loads on the electromagnetic transmission performance is nonignorable....
High- performance amorphous thermoplastics such as polyetherimide (PEI) are widely used in aerospace applications; however, thick- walled sections are prone to internal void formation due to volumetric shrinkage and premature gate solidification. In this work, the influence of processing variables on void mitigation in thick- walled PEI components was investigated using an industrially constrained experimental design. Analysis of variance showed that thermal parameters dominated defect variation, with cooling time and mold temperature contributing 50.4% and 30.15%, respectively. Linear regression identified gate freeze time (GFT) as a practical process indicator of pressure- transmission efficiency, exhibiting a strong negative correlation with the maximum void diameter (r = −0.964, R2 = 0.930). A regression- derived threshold of 5.61 s corresponded to the aerospace specification limit of 0.75 mm, and a conservative production target of 6.5 s was recommended based on the 95% prediction interval analysis. Under optimized conditions (160°C mold temperature, 40 s cooling time), the process achieved a GFT of 8.0 s and produced no ultrasonically detectable voids (maximum void diameter < 0.1 mm). Scrap rates decreased from 18.7% to 1.1%, reducing manufacturing cost per accepted part. These findings establish GFT as a practical mechanistic indicator for process- window development in thick- walled high- performance thermoplastics....
High-velocity fragment impact on aircraft thin-walled aluminum alloy structures typically induces severe debris cloud generation, which causes widespread secondary damage to internal equipment and greatly impairs structural survivability and post-damage repairability. Polyurea, as a lightweight hyper-elastomeric protective material, shows great potential in mitigating impact-induced damage, while its inhibitory effect and underlying mechanism on post-target debris cloud effects remain to be fully elucidated. In this study, we designed and fabricated polyurea-coated aluminum plate specimens with different coating configurations (rear-face single-sided coating and double-sided sandwich coating) and conducted systematic ballistic impact tests under 1300–1400 m/s fragment impact using a 14.5mm ballistic gun system. The optimized test setup enabled direct and quantitative observation of the regulation effect of polyurea coatings on post-target debris cloud evolution. Experimental results show that polyurea coatings can effectively suppress debris cloud diffusion and reduce secondary damage, and the rear-face coated configuration (Type A) exhibits optimal post-target effect mitigation performance: the debris cloud dispersion angle is reduced from 67.5°1.2° (uncoated plate) to 58.2°1.1°, and the maximum distribution radius of secondary impact craters on the witness plate is reduced by 46.7% compared with the uncoated specimen. Furthermore, a finite element model coupled with the adaptive FEM-SPH method was established and validated against experimental data to reveal the physical mechanism of polyurea’s protective effect. The results demonstrate that the excellent hyperelasticity, high fracture strain, and energy absorption capacity of polyurea are the core factors for debris suppression: the polyurea coating achieves debris entrapment through large deformation and contraction, dissipates impact energy via viscoelastic dissipation, and modulates stress wave propagation to reduce aluminum substrate spalling and debris generation. This study clarifies the inhibitory mechanism of polyurea coatings on post-target secondary effects under highvelocity impact and provides valuable experimental and theoretical guidance for the lightweight protective design of aircraft thinwalled structures using polyurea materials....
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