Search Results (79)

As one of the busiest airports in East China, effective bird-strike prevention is of paramount importance for Hangzhou Xiaoshan International Airport. Ground-dwelling insects in airport grasslands serve as a critical food source for insectivorous birds, making the study of insect communities essential for understanding bird activity patterns and mitigating bird-strike risks from a food chain perspective. This study investigates the communities of insects, birds, and vegetation in the flight zone and clear zone of Hangzhou Xiaoshan International Airport. Based on monthly surveys conducted from January to December 2024, we analyzed insect community composition and diversity, assessed bird-strike risks, and examined correlations between insect and bird communities. The results recorded a total of 7744 birds belonging to 107 species, 43 families, and 15 orders in the flight zone and clear zone. Passeriformes was the most species-rich order, and resident birds dominated the avian community. Bird species richness and abundance peaked in spring and autumn. In the flight zone, 18 bird species (e.g., Hirundo rustica) were classified as highly hazardous (R ≥ 15, where R is the calculated risk index) or above. The vegetation survey identified Cynodon dactylon as the dominant plant species in the flight zone. Importantly, positive trends were observed between insectivorous birds and insect abundance, though correlations did not reach statistical significance. To reduce food availability for birds, we recommend stringent management of the grassland habitat in the flight zone, including targeted insect control measures. Given the airport’s location along the East Asian-Australasian Flyway, enhanced bird dispersal efforts should be implemented during peak migration seasons. This study provides a crucial ecological foundation for developing an integrated “vegetation–insect–bird” management strategy for bird-strike prevention at Hangzhou Xiaoshan International Airport and similar aviation hubs. Full article

Thin wall composite fan blades in aircraft engines demand designs that ensure structural integrity under operational loads while resisting foreign object damage and bird strikes. This study presents a finite element investigation of thin wall composite blades with metal leading edge caps, modeled through parametric coupon analyses under static flexure loading using ANSYS APDL. Three metallic leading edge caps, Ti-6Al-4V, Inconel 718, and 15-5 PH stainless steel, were combined with IM7/8551-7 carbon fiber composites. Parametric variations included changes in metal cap material, geometric designs of the joint, and other things. Performance was evaluated in terms of failure stress, interlaminar shear strains, interface integrity, and failure margins. Results reveal that cap design and cap material critically govern structural response, with distinct interchanges between strength-to-weight efficiency, interface stresses, and interlaminar shear strain. Optimal designs reduced interlaminar shear strain levels in thin wall composite blades, while retaining adequate stiffness and strength. The results underscore the importance of interface design for effective load transfer and provide design guidelines for lightweight, damage-tolerant thin wall composite fan blade structures. Full article

Urban Air Mobility (UAM) promises to reduce ground traffic and journey times by using electric vertical take-off and landing (eVTOL) aircraft for short, low-altitude flights, especially in urban environments. However, low-flying aircraft are at particularly high risk of collisions with wildlife, such as birds. This study builds on previous research into UAM collision avoidance systems (UAM-CAS) by implementing one such system in the BlueSky open-source air traffic simulator and evaluating its efficacy in reducing bird strikes. Several modifications were made to the original UAM-CAS framework to improve performance. Realistic UAM flight plans were developed and combined with real-world bird movement datasets representing typical birds in sustained flight from all seasons, recorded by an avian radar at Leeuwarden Air Base. Fast-time simulations were conducted in the BlueSky Open Air Traffic Simulator using the UAM flight plan, the bird datasets, and the UAM-CAS algorithm. Results demonstrated that, under modelling assumptions, the UAM-CAS reduced bird strikes by 62%, with an average delay per flight of 15 s, whereas 27% of the remaining strikes occurred with birds outside the system’s design scope. A small number of flights faced substantially longer delays, indicating some operational impacts. Based on the findings, specific avenues for future research to improve UAM-CAS performance are suggested. Full article

Community-sourced biodiversity imagery has expanded rapidly in the past decade, facilitating analyses of ecology on unprecedented spatial scales. Proliferation of these databases has also helped to reveal understudied or previously overlooked aspects of many species’ basic biology. The Evening Grosbeak (Hesperiphona vespertina) is considered to be a species of conservation concern, and many aspects of its diet have yet to be investigated, including how its diet varies seasonally and across its large North American range. The Evening Grosbeak’s striking plumage, frequent occurrences at bird feeders, and nomadic behavior all make them popular targets of bird photographers and a prime species for study using large community-sourced archives. We reviewed more than 50,000 photographs of Evening Grosbeaks archived in the Macaulay Library, a large public database, to gain a more detailed understanding of the diet of this species. While most Evening Grosbeak images found in the Macaulay Library depicted birds foraging at bird feeders, 1075 images were found to be of birds consuming natural (non-feeder) food items. We mapped the location of these natural dietary items to four distinct regions within the Evening Grosbeak’s geographical range and found a diet consisting of at least 96 species of plants from 25 families, 1 species of insect, and 2 species of lichen from 1 family. Despite the high diversity of dietary items we identified, richness estimators suggest even greater diversity of dietary foods exists, especially in the Pacific Northwest. Using these data and published literature on the Evening Grosbeak’s diet, we discuss the characteristics of preferred Evening Grosbeak dietary items, as well as the advantages and limitations of using community-science data for such analyses. To our knowledge, this is the first range-wide, descriptive study of a songbird species’ diet using photographs made publicly available in a community-sourced archive. Full article

The characterization of material behavior under intermediate deformation rates remains a major challenge, since conventional testing devices are mainly developed for either quasi-static or high strain-rate conditions. Nonetheless, understanding material response in this regime is essential in several applications, such as crashworthiness, bird strike resistance, or metal forming, as well as for the development of reliable constitutive models. In this work, the design and validation of a novel electromechanical apparatus for intermediate strain-rate testing (∼1–10² s⁻¹) of various materials is presented. One of the novelties of the proposed system is the integration of high-performance electromechanical actuators capable of reaching velocities up to 3 m/s, with 16,000 m/s² acceleration, and impact forces up to 24 kN. During testing, one specimen end is impacted by a striker while the other is in contact with a 14.5 m transmitter bar. Upon impact, the sample deforms, and a compressive stress wave propagates in the transmitter bar. Strain gauges are employed to measure its deformation and, therefore, the force transmitted to the sample. The velocity and displacement of the impact head are instead recorded with high temporal resolution and accuracy by integrating Photon Doppler Velocimetry (PDV) into the system. Validation tests performed on polycarbonate confirmed the accuracy, repeatability, and overall effectiveness of the apparatus. Full article

Composite materials are widely used in aircraft due to their high specific strength and stiffness, superior impact resistance, and excellent fatigue performance. Bird strikes can inflict severe damage to critical aircraft components such as the fuselage, engines, and wings, thereby compromising flight safety. Aircraft certification regulations require that all components demonstrate a specified level of bird strike resistance before aircraft installation. Given these requirements, this study focused on the use of carbon fiber composite laminates in aircraft components. By varying impact velocity, impact angle, and ply orientation, the study investigated the resulting patterns of bird-strike impact behavior in composite materials. The derived patterns provide a theoretical reference for further research into the impact mechanics of composite materials subjected to bird strikes. Full article

Accurate assessment of avian community structure and bird-strike risk within airport ecosystems is vital for balancing aviation safety with biodiversity conservation. From October 2019 to July 2020, we conducted systematic bird surveys at Lincang Boshang Airport (Yunnan, China) and its surrounding area. By integrating taxonomic, functional, and phylogenetic diversity analyses, we examined spatial–temporal patterns of bird diversity and characterized bird-strike risk. In total, 4859 individuals of 148 species were recorded, representing 51 families and 15 orders. The avifauna was dominated by broadly distributed Oriental–Palearctic species, reflecting the pronounced biogeographic transition of southwestern Yunnan. Functional diversity (FD) and phylogenetic diversity (PD) differed significantly among habitats: wetlands exhibited the highest FD and PD, indicating strong functional and lineage overdispersion driven by high environmental heterogeneity, whereas farmland showed the lowest FD and PD, consistent with stronger environmental filtering. Seasonal dynamics also shaped community structure, with the highest individual abundance in winter and the lowest species richness in spring. Standardized effect sizes (SES) revealed an overall tendency toward functional and phylogenetic clustering (SES < 0), most pronounced in forest and urban communities, while wetland assemblages consistently showed greater overdispersion across seasons. Risk evaluation indicated that low-risk species comprised 76.35% of the fauna, whereas high and very-high risk species accounted for only 3.38%, mainly large raptors (Accipitriformes) and pelicans/herons (Pelecaniformes). Integrating community patterns with risk distribution, we propose zone-specific management: remove standing water and tall grass in wetlands and farmland; optimize vegetation structure along forest–urban edges; and adopt acoustic/visual deterrents and dynamic management within core airport areas to reduce strike risk. Our findings provide a comprehensive baseline of airport bird diversity and bird-strike risk in southwestern China, offering evidence-based guidance for airport ecological safety management and regional biodiversity conservation. Full article

Vertebrate pollination is widespread in Musaceae, with birds and bats serving as the main pollen vectors across the family. While these systems are typically well defined, the Golden Lotus (Musella lasiocarpa) has long been regarded as an exception, presumed to rely on insect, particularly bee, pollination. In this study, we challenge that assumption by providing the first comprehensive evidence of bird visitation and putative pollination in M. lasiocarpa. Through field surveys complemented by citizen science observations, we documented an unexpectedly rich assemblage of avian visitors: twelve bird species from five families regularly foraged at flowers and likely acted as pollinators. This represents a striking expansion of the known potential pollinator spectrum for the species and highlights a previously overlooked dimension of its reproductive ecology. The floral traits of M. lasiocarpa, including vivid bracts, accessible nectar, and extended flowering, align closely with adaptations to bird pollination. Beyond clarifying the natural history of the Golden Lotus, our findings reveal broader insights into the ecological and cultural significance of bird pollination in the Chinese flora, with implications for both biodiversity conservation and horticultural practices. Full article

We propose MTC-BEV, a novel multi-modal 3D object detection framework for autonomous driving that achieves robust and efficient perception by combining spatial, temporal, and semantic cues. MTC-BEV integrates image and LiDAR features in the Bird’s-Eye View (BEV) space, where heterogeneous modalities are aligned and fused through the Bidirectional Cross-Modal Attention Fusion (BCAP) module with positional encodings. To model temporal consistency, the Temporal Fusion (TTFusion) module explicitly compensates for ego-motion and incorporates past BEV features. In addition, a segmentation-guided BEV enhancement projects 2D instance masks into BEV space, highlighting semantically informative regions. Experiments on the nuScenes dataset demonstrate that MTC-BEV achieves a nuScenes Detection Score (NDS) of 72.4% at 14.91 FPS, striking a favorable balance between accuracy and efficiency. These results confirm the effectiveness of the proposed design, highlighting the potential of semantic-guided cross-modal and temporal fusion for robust 3D object detection in autonomous driving. Full article

This research presents a novel methodology for lightweighting and cost reduction of components with high structural demands by integrating advanced design and manufacturing techniques. Specifically, it combines topology optimization (TO) with additive manufacturing (AM), also known as 3D printing. Unlike conventional approaches, the proposed method first determines the optimal geometry using an artificially stiff material, and only then evaluates real materials for structural and manufacturing feasibility. This design-first, material-second strategy enables broader material screening and maximizes weight reduction without compromising performance. The proposed workflow is applied to the design of a turbofan air intake—an aeronautical component operating under supersonic conditions—addressing both structural integrity and manufacturing feasibility. Three materials from distinct classes are assessed: two metallic alloys (aluminum alloy 6061 and titanium alloy, Ti6Al4V) and a high-performance polymer (polyetheretherketone, PEEK). This last option is preliminarily discarded after being analyzed for this specific application. Finite element (FE) simulations are used to evaluate the mechanical behavior of the optimized geometries, including bird-strike conditions. Among the evaluated manufacturing techniques, Selective Laser Melting (SLM) is identified as the most suitable for the metallic materials selected, providing an effective balance between performance, manufacturability, and aerospace compliance. This study illustrates the potential of TO–AM synergy as a sustainable and efficient design approach for next-generation aerospace components. Simulation results demonstrate a weight reduction of up to 71% while preserving critical functional regions and maintaining structural integrity in Al 6061 and Ti6Al4V cases, under the diverse loading conditions typical of real flight scenarios, while PEEK remains an attractive option for uses where mechanical demands are less stringent. Full article

Wildlife strikes in aviation are among the most reported safety incidents. As such, strikes have become the fundamental unit of understanding of the risk posed by wildlife. However, the management of wildlife risks to aviation has shifted to a hazard management philosophy. This literature review examines the argument that current wildlife strike reporting requirements are inadequate for modern wildlife hazard management techniques. This review utilised bibliometric analysis software to identify relevant academic research sourced from the Web of Science, as well as industry materials, to compile a final catalogue (n = 542). Further filtering revealed a limited set of relevant papers (n = 42) and even fewer papers that addressed the above question. Analysis of these papers and the wider catalogue noted limitations in current reporting requirements as they relate to hazard and risk management concepts. This analysis was supplemented with a review of international standards and relevant national requirements, concluding that while academics and industry have adopted systematic safety and hazard management techniques, and international guidance material has kept pace, international standards, the foundation for many national reporting systems, remain decades behind. This paper proposes the use of robust consensus-building methodologies, such as the Delphi technique, in the industry as a means of streamlining and supporting international standards development. Full article

A turboprop aircraft is exposed to the risk of bird strikes during flight, which may have a serious impact on flight safety once the bird is sucked into the engine. In this study, the aerodynamic and bird exclusion characteristics of a branched turboprop inlet were tested on a branched turboprop inlet–bird striking experiment system under ground suction conditions. The ingestion processes of the bird were captured by a high-speed camera system. The static pressure at the inner wall of the inlet during the ingestion process was measured. The results indicate that when a low-speed bird at a large incident angle impacts on the wall of the inlet near the lower lip under ground suction conditions, the bird is easily sucked into the core duct. Conversely, it is more likely to be excluded by the bypass duct. Moreover, when the bird moves into the inlet, the static pressure on the wall of the area where it passes through increases significantly. Full article

The wind turbine blade is subject to multi-source impacts, such as bird strikes, lightning strikes, and hail, throughout its extended service. Accurate localization of those impact sources is a key technical link in structural health monitoring of the wind turbine blade. In this paper, a single-sensor impact source localization method is proposed. Capitalizing on deep learning frameworks, this method innovatively transforms the impact source localization problem into a classification task, thereby eliminating the need for anisotropy compensation and correction required by conventional localization algorithms. Furthermore, it leverages the inherent coding effects of the blade’s material and geometric anisotropy on impact sources originating from different positions, enabling localization using only a single sensor. Experimental results show that the method has a high localization accuracy of 96.9% under single-sensor conditions, which significantly reduces the cost compared to the traditional multi-sensor array scheme. This study provides a cost-effective solution for real-time detection of wind turbine blade impact events. Full article

The use of composite materials in aerospace structures has led to significant weight reductions and improved performance. However, their behavior under low-energy impact remains a critical concern due to the potential initiation of barely visible damage. This study investigates the crack initiation mechanisms in composite airfoil profiles subjected to low-energy impact, simulating real-world scenarios such as hail or bird strikes. Two types of airfoil profiles were fabricated using bidirectional carbon fiber reinforced polymer (CFRP) with epoxy resin and tested under ASTM D7136 impact conditions. Tensile tests following ASTM D3039 were conducted to assess post-impact mechanical behavior. The damage patterns were analyzed using high-resolution microscopy and non-destructive inspection techniques. Results revealed that damage severity and propagation depend on impact energy levels and airfoil geometry, with SC(2)-0714 exhibiting better impact resistance than GOE777-IL. Microscopic analysis confirmed that delamination initiated at 45° fiber orientations, expanding along interlaminar regions, while airfoil curvature influenced the impact energy dissipation. Full article

Bird strikes pose a significant threat to aviation safety, particularly affecting the wing structures of aircraft. This research aims to design and analyze the impact of bird strikes on wing structures using response surface method and metaheuristics (MHs), which are used to explore various risk minimization and damage mitigation techniques. The optimization problem is the minimization of the maximum von Mises stress of aircraft wing structure against bird strike that is subject to displacement and stress constraints. The design variables include skin and rib thickness, as well as sweep angle. Difficulty due to embedded bird strike simulation and optimization design can be alleviated using a response surface method (RSM). The regression technique in the RSM of the data can reach our goal of model fitting with a higher R² until 0.9951 and 0.9919 are obtained for the displacement and von Mises stress model, respectively. The response surface function of the displacement and von Mises stress are related to skin thickness, while sweep angles rather than rib thickness have a greater impact on both design variables. The optimized design of the design variables is performed using MHs, which are TLBO, JADE, and PBIL. The comparative result of MHs can conclude that the PBIL outperformed others in all descriptive statistics. The optimized design results revealed that the optimum solution can release better energy due to bird strike with the highest limit of skin thickness, moderate rib thickness, and less than half of the sweep angle. The results are in accordance with the response surface function analysis. In conclusion, the optimized design of the aircraft wing structure against bird strike can be accomplished with our proposed technique. Full article