Proceedings of the International Conference on Aerospace System Science and Engineering 2022

The design of glazing is one of the most important tasks in the design of the cockpit of an aircraft. Modern design technologies simplify and accelerate the process of creating and analyzing any products including the crew cabin.

Due to the numerous alarm entries and dense text on the interface of the onboard maintenance system (OMS), it is still challenging for current algorithm to achieve complete and accurate text recognition based on screen. This paper proposes a deep learning method that employs YOLOv3, CRNN and a post-processing module. This method first uses YOLOv3 to locate some text which we really concerned; then the feature map of the positioning area is aligned and fed to the CRNN text recognition module to obtain the text detection result, and finally the text matching module based on the minimum edit distance is used to solve some hard cases. During the experiment, we also discussed the limits of each module and made some improvements. The experimental results demonstrate that the approach we proposed has an accuracy of 99.95% and a recall of 95.74%, indicating that our algorithm can solve the problems of incomplete localization and inaccurate text recognition, and can meet practical application scenarios.

In order to evaluate different agile aircraft development solutions and select a reasonable solution from them, a comprehensive evaluation index system of agile aircraft development process is constructed in this paper. Taking into account the interaction among the evaluation indicators, the evaluation model is established by using the Delphi method and analytic network process, so as to determine the comprehensive weights of each indicator in the evaluation system of agile aircraft development process based on Delphi-ANP.

The software ANSYS was used to perform structural model analysis, cavity acoustic modal analysis, model analysis on acoustic-structure coupled system and harmonic response analysis of an aircraft-aileron-cabin model. The resonance frequencies of cavity with a gap versus the gap width was established based on Helmholtz resonance theory. The results are roughly in agreement with the numerical simulation results obtained with ANSYS in trend. The acoustic-structure coupling analysis show that there were two vibration modes when the natural frequency of cavity is approaching to that of the structure in the coupled system, and the magnitude of frequency resonance function on acoustic pressure and structural vibration are sensitive to the gap width. This study provides an effective method to analyze and design on the thin-walled cavity with gap in aircraft exposed to noise environment.

The tensile test of composite material sample is a traditional mean of obtaining its strength and stiffness. The standard for conducting this experiment is ASTM D3039, where the general requirements, tooling and parameters of loading are presented. In the meantime the standard provides several modes of sample’s failure, which are likely to be met in practice. By default, the failure location in the middle of specimen is the most desirable (denoted as LGM). Other modes of failure might be treated as unacceptable result of testing, for example splitting of the material parallel to loading direction (denoted as SGM). There are many studies researching the influence of different parameters on failure mode and depending on them, the different failure modes were obtained. In current paper the attained results intersect with a results produced previously by few of other studies. The simulation via finite elements method (FEM) can become helpful instrument in assessment of sensitivity of localization and nature of failure to different parameters, such as material system used, geometry of the sample and tooling.

During conceptual design of complex civil aircraft systems, it is indispensable for systems engineers to establish functional architectures, which serve as the basis for subsequent detailed design. Since document-based descriptions of functional architectures tend to result in ambiguities and inconsistencies, academia has been devoted to the formal representation of functional architectures, with the aid of Model-Based Systems Engineering. However, traditional functional modeling approaches generally focus on input-output transformations, rather than state (mode) transitions of systems, which hinders the engineers from representing explicitly the functional architectures involving state-transition logic (e.g., specific signals should trigger the state of landing gear systems to change from retracted to extended, or vice versa). Furthermore, lack of formal representation of the state transitions makes the engineers rely on manual analysis to verify the functional architectures, which can be time-consuming and error-prone. To address this issue, this paper develops a SysML-based approach for functional modeling of civil aircraft systems. First, a state-integrated functional model of components is proposed; thereafter, the integration of the component functional models is proposed; Finally, the landing gear systems is employed to demonstrate the proposed approach above, followed by an illustrative case of functional simulation.

Recently, ultralight UAVs (unmanned aerial vehicles) have been increasingly usedto solve the tasks of exploring territories, both in the military and in the civilian sphere. The main criterion for guaranteeing the fulfillment of the task is the accuracy of its positioning in space. As a rule, the main equipment for determining the location is a GLONASS/GPS receiver, which receives a signal from satellites with interference, delays, or may be missing. The article proposes a new method of orientation of an ultralight UAV by searching for previously defined terrain landmarks when processing data from an on-board photo recorder and movement from one such object to another. The paper describes an algorithm for generating data on terrain landmarks, UAV action scenarios, and an algorithm for optimizing the movement of UAVs when moving from one landmark to another.

In this article, the object of research is various layouts of unmanned aerial vehicles with a small turbojet engine using an ejector thrust magnifier. The author develops aerodynamic layouts of unmanned aerial vehicles taking into account the required size and operating speed range, determines the optimal aerodynamic scheme, performs a numerical calculation of the engine operation with an ejector thrust booster, optimizes design parameters in the XFLR5 and ANSYS software packages.

Currently, unmanned aerial vehicles of various tactical and technical parameters, sizes and masses are being developed. The engines will be improved increasing efficiency and improving the characteristics: thrust, efficiency and mass. The rapid development of unmanned aerial vehicles is due to the advantages they have, for example: the absence of crew members eliminates the risk of human losses, the ability to perform maneuvers with an overload exceeding the physical capabilities of pilots, as well as the absence of a crew fatigue factor. The cost of unmanned aerial vehicles has been reduced, and lower operating costs allow for the mass production of inexpensive but efficient aircraft.

The article presents graphs of changes in the aerodynamic characteristics of the considered layouts of unmanned aerial vehicles, the results of numerical calculation during the operation of the engine in flight with an ejector thrust booster, a comparison of the results obtained, as well as options for optimizing design parameters, which is the main purpose of the study in this work.

The paper compares the strength of fiber-reinforced composites with and without fabrication defects. The influence of the initial waviness of the fibers on the behavior of the material during longitudinal compression is revealed. The samples are modeled using Python and then imported into Simulia Abaqus. The analysis is carried out by means of computational micromechanics using representative volume element (RVE). A two-dimensional deformable RVE with a volumetric fiber content of 50% is modeled. There are no initial stresses in the material. The input data for modeling are the elastoplastic and strength properties of the components, the geometry and the size of the RVE. A mesh in the form of triangular elements was superimposed on the sample. Post-processing includes an assessment of the strength of micromechanical samples with straight and initially wavy fibers. The data obtained can be used in the preparation and implementation of a test program for composite materials and also in understanding of influence of fabrication defects on theirs strength properties.

At the outbreak of COVID-19, researchers worldwide are seeking approaches to containing this disease. It is necessary to monitor social distance in enclosed public areas, such as subways or shopping malls. Passive localization, such as surveillance cameras, is a natural candidate for this issue, which is meaningful for rapid response to finding the infected suspect. However, the latest surveillance camera system is rotatable, even movable. And it is impossible for professionals to regularly calibrate the extrinsic parameters in a large-scale application, like COVID-19 suspect monitoring. We propose an inertial-aided passive localization method using surveillance camera for social distance measurement without the necessity to obtain extrinsic parameters. Moreover, the hardware modification cost of the off-the-shelf commercial camera is low, which suits the immediate application. The method uses SGBM (Semi-Global Block Matching) for 3D reconstruction and combines YOLOv3 and Gaussian Mixture Model (GMM) clustering algorithm to extract pedestrian point clouds in real time. Combining the 2D DNN-based and model-based methods makes a better balance between the computational load and the detection accuracy than end-to-end 3D DNN-based method. The inertial sensor provides an extra observation for the coordinate transformation from the camera frame into the world ground frame. Results show we can get a decimeter-level social distancing accuracy under noisy background and foreground environments at a low cost, which is promising for urgent COVID-19 public area monitoring.

In order to reduce the computational cost of Large Eddy Simulation method at high Reynolds number, the hybrid LES/RANS model-Improved Delayed Detached Eddy Simulation (IDDES) method based on k-ω SST turbulence model is used to simulate a 2.84 Mach number flow of the 24° compression ramp. The effects of two kinds of inlet boundary conditions which includes fixed inlet and turbulent inlet were investigated. The numerical simulation reproduces the phenomena of boundary layer separation, shock separation and reattachment. The results show that the length of simulated separation region under the fixed boundary condition is significantly larger than the experimental result, and the length of the separation region under the turbulent inlet decreases with the increase of turbulent intensity, which is gradually close to the experimental results. The results show that the IDDES hybrid model is very dependent on the turbulence of the incoming flow.

To design and invent a new type of reliable inlet distortion screen facility plays an important part in the current flight compliance certification. In order to achieve the design as well as analyzing and verifying the outlet distortion flow field, this paper relied on the existing equipment of the Shanghai Jiao Tong University Aero Engine Research Institute, designed and processed a new inlet distortion screen facility. In the small wind tunnel, the facility was installed to achieve inlet distortion conditions, and 30 sets of basic meshes were selected to operate wind tunneling test under wind speed of different Mach number. Through the finishing of the test data, the experiment acquired the resistance coefficient and loss characteristics of the 30 sets of basic meshes, and summarized the test data according to its geometric parameters. Then the test selected distortion meshes from the former basic meshes, and operated followed-up wind tunneling test. The simulation achieved inlet distortion conditions. With analyzing of the data acquired by the pressure sensor, the test obtained the loss characteristic curve and the surface pressure distribution of the distortion screen facility. The results showed that the designed distortion screen facility was well simulated the flow field characteristics of different distortion angles under the Airworthiness requirements, which proves the feasibility of the method. The distortion device can also provide familiar flow field distortion assessment for the same type of aero engine.

Due to the large dispersion of composite materials, in order to obtain statistical value of the strength of composite laminates, the current method relies on a large number of experiments, which requires extremely high labor, time, and costs. This paper proposes a new parametric modeling method to cover the effects of random deviation variables (material properties, layup angle and laminates thickness) on strength of composite laminates. The Monte-Carlo method is used to generate a large number of laminates models with random variation of composite material properties. The model is established and revised by tensile and compression tests of 0° and 90° laminates. Then the method is validated by open-hole compression tests of composite laminates with four different layers. The errors of average and coefficient of variation between simulation and test results are compared. The modeling method with random deviation variables in this paper can be used to reduce the allowable value test of composite laminates.

Recently, system functional simulation mostly uses discrete functional logic models, and it is difficult to simulate the impact of continuous behavioral parameter changes on functional logic. To remedy the addressed issue, a functional simulation method integrating a discrete functional model and continuous behavior model is proposed to help engineers analyze the correctness of functional design efficiently. Firstly, a component functional modeling and a system functional architecture modeling method are established based on state machine; secondly, a model integration simulation method based on FMI is established to integrate discrete function models and continuous behavior models of components or systems; Finally, this paper takes the aircraft elevator system as an example to verify the application of functional modeling and simulation methods. The application results show that the functional modeling and the simulation method which integrates dynamic behavior can simulate the continuous behavior and the system function execution effectively. Thereby, the engineers can ensure the correctness of the system design with this method.

The test of the autoclave temperature field is very important for the quality control of the civil aircraft composite material manufacturing. The existing test methods mainly arrange thermocouples on the front and tail sections and geometric center of the autoclave for multi-point distributed measurement. However, the reason why temperature tests are mainly carried out on the front and tail sections, the detailed sensor arrangements, as well as the requirements for the local layout of the thermocouple measuring junctions are still unclear. A three-dimensional steady-state numerical simulation of the autoclave temperature field is performed in this article. The discrete distribution tests showed that the actual temperature distribution is consistent with the numerical simulation results with the effects of the front and rear rectifier plates considered. The low-temperature area was observed in the tank door and top, whereas the high-temperature area was distributed in the tank tail and bottom. The flow field near the rectifier plates on both sides was more complicated as compared with that in other regions. The microstructure did not significantly affect the overall temperature field in the tank, whereas it exerted a greater effect on the local temperature field. The temperature distribution of the entire autoclave can be represented by the typical measurement points. Additionally, local layout requirements of test sensors are proposed, which can provide a basis for determining the point for the autoclave temperature field test.