Based on the biaxial experiment data of the membrane material under hot and cold conditions, the mechanical properties calculation model of envelope material was established with consideration of the effects of varying stress ratios, stress magnitudes and temperatures on the mechanical properties of near-space airship material. Using the heat source model, Computational Fluid Dynamics (CFD) simulation, User-Defined Function (UDF), structural finite element analysis software and the user subroutine of an airship to define the behaviour of fabric material, the fluid–structure–thermal coupling model of airship envelopes was established. In addition, a near-space airship was selected as the research subject to calculate the diurnal temperature differences during the summer solstice and analyse the diurnal temperature distribution of the envelope. Under controlled environmental conditions, the deformation law of the near-space airship under the influence of fluid–structure–thermal coupling was calculated and summarised. The present fluid–solid–thermal coupling model takes into account the anisotropy of materials, temperature, stress magnitude, stress ratio and other influencing factors, which can more accurately reflect and predict the stress–strain distribution and the deformation law of near-space airships.

This paper describes a shape exploration and multidisciplinary optimization method of unconventional semirigid nearing space airships. The approach includes several improved mutually interacting di...

Stratospheric airships have much potential in military and commercial applications. Design, analysis and optimization of stratospheric airships involves complex trade-off of different disciplines, and hence a multidisciplinary approach is essential. This paper describes a methodology coupling several disciplines and involving seven design variables to obtain the optimal design of a stratospheric airship powered by solar arrays. A numerical method is established to calculate the output power of the solar array in the optimization process. The optimal solutions are obtained using hybrid algorithms. The methodology can obtain the optimal envelope shape, solar array layout and other general configurations of subsystems. Results show that the methodology was able to achieve a solution with a 19.2% reduction in airship volume compared to the value being part of an arbitrary initial set of airship parameters. In addition, a comparative study is carried out to highlight the importance of considerations of solar array layouts and array circumferential location. Furthermore, detailed sensitivity analysis shows that operating parameters of latitudes, heading angles and average resisting wind speeds have significant effects on the airship design and solar array layouts.

A comprehensive simulation model is established to predict the trajectory of a high-altitude zero-pressure balloon flight system with no parachute that is required to carry the load floating at the designated altitude for several hours or less. A series of mathematical models, including thermal dynamic, atmospheric, earth, wind, geometry, and exhaust models, are developed to predict the trajectory of the balloon flight system. Based on these models, the uncertainties of the launch parameters and the corresponding flight performance are simulated. Combined with the control strategy, the entire flight trajectory is simulated and discussed in detail, including the ascending, floating, and descending phases. The results show that the vertical velocity takes on a W shape during the ascent process. Furthermore, the balloon begins to gradually descend with weakening solar radiation after noon. Moreover, the landing vertical speed of the balloon flight system can approach zero with the control strategy applied, whereas the lateral drift range is more limited relative to the uncontrolled flight mode. The results and conclusions presented herein contribute to the design and operation of a zero-pressure balloon flight system within limited airspace to improve the rapid recovery ability of the flight system.

An optimal calculation method for the mechanical properties of near-space capsule materials was proposed. First, biaxial tensile tests under low tensile ratios were carried out on the envelope materials of a near-space airship. The experimental results showed that the values of the elastic modulus and Poisson’s ratio, which are significantly affected by the warp and weft stresses, were not constant. Second, the elastic modulus and Poisson’s ratio of the near-space airship were obtained by using the traditional calculation method, and the limitations of this method were discussed. Third, an optimal calculation model for the elastic modulus and Poisson’s ratio of airship envelopes was proposed. The strain calculated by the proposed optimization model could be effectively correlated to the strain measured by the experiment. Then, through the user-defined subroutine of the finite element method and the elastic modulus and Poisson’s ratio calculated by the proposed optimization, the strain of the finite element simulation was obtained. The average error between the simulation results and the experimental values was approximately 8.21% (warp) and 8.41% (weft). The proposed method can consider the nonlinear changes of the elastic modulus and Poisson’s ratio of membrane material under different stress ratios and predict the force and deformation of the airship’s capsule more accurately, which is adaptable to engineering applications.

As the key mechanism of attitude control of micro/nano-satellites, the flywheel design is mostly based on empirical formulae that do not meet the requirements of lightweight and high-performance micro/nano-satellite platforms. In this paper, the structural shape of micro/nano-satellite flywheels is analysed, and a set of flywheel optimisation methods is proposed to realise the parametric optimisation analysis of the structural shape. First, the general principle of flywheel efficiency is introduced, the optimisation evaluation factor of flywheel design is proposed, and the parametric model of a flywheel structure is established by using the finite element secondary development technology, which can be used to quickly build a finite element model of different dimensions. Second, the optimisation model of flywheels is established while introducing the approximate model algorithm, greatly improving the optimisation efficiency. Considering the phenomenon that the genetic algorithm falls below local optimisation under a large parameter range, the method of initial optimisation is proposed to reduce the upper and lower limits of the optimisation parameters. Finally, the optimal shape of the flywheel is obtained by using the parametric optimisation model of the flywheel. The finite element analysis results show that the flywheel optimisation evaluation factor proposed in this work can effectively improve the comprehensive performance of the flywheel as the optimisation target, and the corresponding optimisation method can be well applied to the engineering application and design of micro/nano-satellite platforms. This can help guide the structural optimisation design of micro/nano-satellite platforms in the future.