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This paper presents a theoretical investigation into the potential use of structural power composites in regional aircraft passenger cabins and the corresponding challenges to widespread use, including fire-resistance, long-term cycling performance, and cost. This study focusses on adapting sandwich floor panels with structural power composite face sheets, designed to power the in-flight entertainment system. Using a simple mechanical model to define the structural requirements, based on state-of-the-art laminated structural power composites, a series of electrochemical energy storage performance targets were calculated: a specific energy > 144 Wh/kg, a specific power > 0.29 kW/kg, an in-plane elastic modulus > 28 GPa and in-plane tensile and compressive strengths > 219 MPa. Significantly, the use of a distributed energy storage system offered a significant range of other mass and cost savings, associated with a simplified power system, and the use of ground-generated electrical energy. For an Airbus A220-100, the analysis predicted potential mass and volume savings of approximately 260 kg and 510 land annual reductions in CO2and NOx emissions of approximately 280 tonnes and 1.2 tonnes respectively. This extended design analysis of a specific component highlights both the far-reaching implications of implementing structural power materials and the potential extensive systemic benefits.

This study investigates the viability of implementing multifunctional structural power composites in a four-seater air taxi, the CityAirbus. For a given specific energy of the power source, the cruise endurance can be approximately doubled by using structural power composites as opposed to conventional batteries. Replacing all the eligible composite mass and batteries with structural power composites can reduce the CityAirbus weight by 25%. To achieve the current design performance, the minimum required elastic modulus, strength, specific energy and power for the structural power composite are 54 GPa, 203 MPa, 74 Wh/kg and 376 W/kg, respectively: current state-of-the-art structural power composites are now approaching this level of performance. Hence, structural power composites are considered feasible for adoption in the urban air mobility sector and have the potential to improve endurance and facilitate commercialization. This paper also discusses several key challenges that must be addressed to realize the adoption of structural power composites in future electric air taxis.

The development of commercial aviation is being driven by the need to improve efficiency and thereby lower emissions. All-electric aircraft present a route to eliminating direct fuel burning emissions, but their development is stifled by the limitations of current battery energy and power densities. Multifunctional structural power composites, which combine load-bearing and energy-storing functions, offer an alternative to higher-energy-density batteries and will potentially enable lighter and safer electric aircraft. This study investigated the feasibility of integrating structural power composites into future electric aircraft and assessed the impact on emissions. Using the Airbus A320 as a platform, three different electric aircraft configurations were designed conceptually, incorporating structural power composites, slender wings and distributed propulsion. The specific energy and power required for the structural power composites were estimated by determining the aircraft mission performance requirements and weight. Compared to a conventional A320, a parallel hybrid-electric A320 with structural power composites &gt, 200 Wh/kg could potentially increase fuel efficiency by 15% for a 1500 km mission. For an all-electric A320, structural power composites &gt, 400 Wh/kg could halve the specific energy or mass of batteries needed to power a 1000 km flight.

To accurately predict the probabilities of impact damage to aircraft from runway debris, it is important to understand and quantify the aerodynamic forces that contribute to runway debris lofting. These lift and drag forces were therefore measured in experiments with various bodies spun over a range of angular velocities and Reynolds numbers. For a smooth sphere, the Magnus effect was observed for ratios of spin speed to flow speed between 0.3 and 0.4, but a negative Magnus force was observed at high Reynolds numbers as a transitional boundary layer region was approached. Similar relationships between lift and spin rate were found for both cube- and cylinder-shaped test objects, particularly with a ratio of spin speed to flow speed above 0.3, which suggested comparable separation patterns between rapidly spinning cubes and cylinders. A tumbling smooth ellipsoid had aerodynamic characteristics similar to that of a smooth sphere at a high spin rate. Surface roughness in the form of attached sandpaper increased the average lift on the cylinder by 24%, and approximately doubled the lift acting on the ellipsoid in both rolling and tumbling configurations.

In January 2020, we identified two SARS‐CoV‐2 infections in a familial cluster with one person coming from Wuhan, China. The complete genome sequences of two SARS‐CoV‐2 strains isolated from these patients were identical and 99.98% similar to strains isolated in Wuhan. This is genetically suggestive of human‐to‐human transmission of SARS‐CoV‐2 and indicates Wuhan as the most plausible origin of the early outbreak in Vietnam. The younger patient with a mild upper respiratory illness and a brief viral shedding, while the elderly with multi‐morbidity had pneumonia, prolonged viral shedding, and residual lung damage. Evidence of nonsynonymous substitutions in the ORF1ab region of the viral sequence warrants further studies. This article is protected by copyright. All rights reserved.

Large transport aircraft are particularly susceptible to impact damage from runway debris thrown up by the landing gear. A methodology was developed to predict the trajectories of stones lofted by the nose wheel and subjected to aerodynamic forces due to the wake behind the nose landing gear and beneath the aircraft. In conjunction with finite element modelling of the stone/ground/tyre contact mechanics, an analytical model was used to perform a stochastic prediction of the trajectories of runway stones to generate impact threat maps which showed the relative likelihood of stones impinging upon various areas on the underside of a C-130 Hercules. The impact envelopes for the C-130 extended three to eighteen metres behind the nose wheel and two metres either side of the centre of the aircraft. The impact threat maps were especially sensitive to the values of the coefficients of lift and drag acting on the stone during its flight.

DOI: 10.2514/1.C031306 This investigation aims to develop a closed-form analytical model to understand and predict runway stone lofting processes by considering the rigid-body interaction of a tire partially rolling over a stone. Any leading-edge aircraft structures impinging into the path of such stones could experience impacts at speeds up to the aircraft takeoff velocity, despite being some distance from the sides of the wheels. The results of the analytical model provide upperbound envelopes of the vertical loft speeds obtained in previous numerical simulations and modified drop-weight experiments. Parametric studies conclude that the vertical loft speeds rise with increasing stone–tire overlap, stone size, and aircraft speed and with deceasing tire diameter. The outcomes of this model form a basis for vehicle designers to assess the runway stone impact threat by better understanding the physics of lofting.

As part of an investigation to assess the impact threat posed to vehicles by tyre-lofted runway debris, it is important to gain a quantitative understanding of the interaction between inflated tyres and foreign objects. In this paper, experiments involving indentation of an inflated tyre to represent over-rolling of a foreign object were used to estimate the energy that could be transferred to the over-rolled object. The maximum kinetic energy that a 24-mm diameter spherical stone could potentially attain from such an indentation-related loft mechanism by a tyre inflated to 0.34 MPa (50 psi) was 20 J.

The influence of various factors affecting the severity of runway debris lofting mechanisms was investigated by performing numerical simulations and drop-weight impact experiments to assess the likelihood of a stone impact. Geometrical characterisation of stones collected from airfields led to a generic model of a tyre rolling over stones of various shape with different overlaps, orientations, and densities. In numerical simulations of a 0.4 m diameter aircraft tyre rolling at 70 m/s, a 10 mm diameter spherical stone was lofted at a maximum vertical speed of 35 m/s. For equivalent mass prolate spheroid stones, the loft speeds were 11–34% lower depending on the stone orientation. Objects with flat surfaces exhibited different lofting mechanisms and lower angular velocities. The conditions most conducive to stone lofting were very stiff, small diameter, sharp cornered tyres rolling on ground with a high friction coefficient over spherical stones such that just under half the stone diameter was covered by the tyre. The stone loft speed was approximately proportional to the square root of the tyre tread stiffness. Finally, tyre tread grooves could throw stones upwards at the tyre-ground separation speed, which was 17 m/s for the conditions mentioned earlier.

Numerical models used to simulate the lofting mechanisms of runway stones were developed to assess the threat to aircraft structures from runway debris impacts. An inflated aircraft tyre model, which was validated by comparison with experimental indentation tests, showed that over-rolling of stones under typical take-off conditions led to only modest vertical loft velocities of less than 5 m/s. Experiments using a drop weight impactor simulated a section of aircraft tyre descending upon stones. These tests demonstrated that lofting was achieved for impacts with low rubber thickness. However, for impacts with greater rubber thickness, lofting was suppressed. Using more realistic tyre geometries resulted in launches with backspin, but only horizontally along the ground in the direction of the tyre axis. The speed at which launches occurred was proportional to the rate of descent of the tyre section and would consequently determine the loft speeds due to potential asperity lofting.

Runway debris lofting by aircraft tires can lead to considerable damage to aircraft structures, yet there is limited understanding of the lofting mechanisms. The aim of this study is to develop accurate physically based models to understand and predict the stone lofting processes. The research entailed both experimental work and finite element modeling of a tire partially rolling over a stone. Parametric studies were conducted to characterize the influence of factors such as stone geometry and tire conditions in the lofting processes. To validate the finite element models, experimental studies were conducted using a modified drop weight impactor covered with rubber to simulate a tire vertically approaching aluminum balls and real stones. A high-speed video camera was used to observe the loft mechanisms and calculate the loft velocities, angles, and spin rates. A finite element model of the impactor demonstrated good agreement with the experimentally observed loft mechanisms.In general, lofting occurred either at high speed and low angles or vice versa, depending on the degree of interaction between the stone and the ground.

Multifunctional composites which can fulfil more than one role within a system have attracted considerable interest. This work focusses on structural supercapacitors which simultaneously carry mechanical load whilst storing/delivering electrical energy. Critical mechanical properties (in-plane shear and in-plane compression performance) of two monofunctional and four multifunctional materials were characterised, which gave an insight into the relationships between these properties, the microstructures and fracture processes. The reinforcements included baseline T300 fabric, which was then either grafted or sized with carbon nanotubes, whilst the baseline matrix was MTM57, which was blended with ionic liquid and lithium salt (two concentrations) to imbue multifunctionality. The resulting composites exhibited a high degree of matrix heterogeneity, with the ionic liquid phase preferentially forming at the fibres, resulting in poor matrix-dominated properties. However, fibre-dominated properties were not depressed. Thus, it was demonstrated that these materials can now offer weight savings over conventional monofunctional systems when under modest loading.

Numerical models used to simulate the lofting mechanisms of runway stones were developed to assess the threat to aircraft structures from runway debris impacts. An inflated aircraft tire model, which was validated by comparison with experimental indentation tests, showed that over-rolling of stones under typical takeoff conditions led to only modest vertical loft velocities of less than 5 m/s. Experiments using a drop weight impactor to simulate a section of aircraft tire descending upon stones, demonstrated that lofting was achieved with impacts with low rubber thicknesses, but with greater rubber thickness lofting was suppressed. Using more realistic tire geometries resulted in launches with backspin, but only horizontally along the ground in the direction of the tire axis. The speed at which launches occurred was proportional to the rate of descent of the tire section and would consequently determine the loft speeds due to potential asperity lofting.

Large transport aircraft are particularly susceptible to impact damage from runway debris thrown up by the landing gear. A methodology was developed to predict the trajectories of stones lofted by ...