Journal articles: 'Expensive aerospace'

1

Shi, Renhe, Teng Long, Nianhui Ye, Yufei Wu, Zhao Wei, and Zhenyu Liu. "Metamodel-based multidisciplinary design optimization methods for aerospace system." Astrodynamics 5, no. 3 (September 2021): 185–215. http://dx.doi.org/10.1007/s42064-021-0109-x.

Full text

Abstract:

AbstractThe design of complex aerospace systems is a multidisciplinary design optimization (MDO) problem involving the interaction of multiple disciplines. However, because of the necessity of evaluating expensive black-box simulations, the enormous computational cost of solving MDO problems in aerospace systems has also become a problem in practice. To resolve this, metamodel-based design optimization techniques have been applied to MDO. With these methods, system models can be rapidly predicted using approximate metamodels to improve the optimization efficiency. This paper presents an overall survey of metamodel-based MDO for aerospace systems. From the perspective of aerospace system design, this paper introduces the fundamental methodology and technology of metamodel-based MDO, including aerospace system MDO problem formulation, metamodeling techniques, state-of-the-art metamodel-based multidisciplinary optimization strategies, and expensive black-box constraint-handling mechanisms. Moreover, various aerospace system examples are presented to illustrate the application of metamodel-based MDOs to practical engineering. The conclusions derived from this work are summarized in the final section of the paper. The survey results are expected to serve as guide and reference for designers involved in metamodel-based MDO in the field of aerospace engineering.

APA, Harvard, Vancouver, ISO, and other styles

2

Ong, Yew S., Prasanth B. Nair, and Andrew J. Keane. "Evolutionary Optimization of Computationally Expensive Problems via Surrogate Modeling." AIAA Journal 41, no. 4 (April 2003): 687–96. http://dx.doi.org/10.2514/2.1999.

Full text

APA, Harvard, Vancouver, ISO, and other styles

3

S, Nikkisha, Rohan S, Pragyan Pattanaik Pattanaik, Ankit Kumar Mishra, and Dheva Darshini. "Review Study on Mechanical and Thermal Properties of Ceramic Materials for Future Aerospace Applications." Materials and its Characterization 1, no. 2 (December 1, 2022): 107–13. http://dx.doi.org/10.46632/mc/1/2/7.

Full text

Abstract:

We are investigating the usage of ceramic materials in the aerospace sector. Ceramics are being used in a restricted number of aeronautical structural applications. Ceramics brittleness, lack of malleability, and expensive cost has been key deterrents to their widespread usage. We can determine the mechanical and thermal properties of this material by studying its mechanical and thermal properties such as strength, hardness, elasticity, grip and fracture, and thermal conductivity, diffusivity, thermal expansion, coefficient of expansion, and diffusivity. Some ceramic materials offer qualities that are important in aerospace applications, as well as the benefits and drawbacks of employing ceramic in the aerospace sector.

APA, Harvard, Vancouver, ISO, and other styles

4

Cai, Xiwen, Haobo Qiu, Liang Gao, Li Wei, and Xinyu Shao. "Adaptive Radial-Basis-Function-Based Multifidelity Metamodeling for Expensive Black-Box Problems." AIAA Journal 55, no. 7 (July 2017): 2424–36. http://dx.doi.org/10.2514/1.j055649.

Full text

APA, Harvard, Vancouver, ISO, and other styles

5

He, Youwei, Jinju Sun, Peng Song, and Xuesong Wang. "Dual Kriging assisted efficient global optimization of expensive problems with evaluation failures." Aerospace Science and Technology 105 (October 2020): 106006. http://dx.doi.org/10.1016/j.ast.2020.106006.

Full text

APA, Harvard, Vancouver, ISO, and other styles

6

Jiang, Ping, Ji Cheng, Qi Zhou, Leshi Shu, and Jiexiang Hu. "Variable-Fidelity Lower Confidence Bounding Approach for Engineering Optimization Problems with Expensive Simulations." AIAA Journal 57, no. 12 (December 2019): 5416–30. http://dx.doi.org/10.2514/1.j058283.

Full text

APA, Harvard, Vancouver, ISO, and other styles

7

Long, Teng, Zhao Wei, Renhe Shi, and Yufei Wu. "Parallel Adaptive Kriging Method with Constraint Aggregation for Expensive Black-Box Optimization Problems." AIAA Journal 59, no. 9 (September 2021): 3465–79. http://dx.doi.org/10.2514/1.j059915.

Full text

APA, Harvard, Vancouver, ISO, and other styles

8

Long, Teng, Xin Li, Renhe Shi, Jian Liu, Xiaosong Guo, and Li Liu. "Gradient-Free Trust-Region-Based Adaptive Response Surface Method for Expensive Aircraft Optimization." AIAA Journal 56, no. 2 (February 2018): 862–73. http://dx.doi.org/10.2514/1.j054779.

Full text

APA, Harvard, Vancouver, ISO, and other styles

9

Parkinson, R. C. "Why Space is Expensive—Operational/Economic Aspects of Space Transport." Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering 205, no. 1 (January 1991): 45–52. http://dx.doi.org/10.1243/pime_proc_1991_205_236_02.

Full text

APA, Harvard, Vancouver, ISO, and other styles

10

Roux, Maxime, Nicolas Eguémann, Clemens Dransfeld, Frédéric Thiébaud, and Dominique Perreux. "Thermoplastic carbon fibre-reinforced polymer recycling with electrodynamical fragmentation." Journal of Thermoplastic Composite Materials 30, no. 3 (August 4, 2016): 381–403. http://dx.doi.org/10.1177/0892705715599431.

Full text

Abstract:

The end of life of carbon fibre-reinforced polymer (CFRP) structures represents a major challenge to the aerospace industry, as new European regulations are demanding recycling solutions that can be complicated and expensive to apply. This study aims to address new practical ways to recycle CFRP materials. CFRP materials with a polyether ether ketone (PEEK) matrix were fragmented via electrodynamical fragmentation, which exhibits several benefits compared to mechanical shredding processes, especially for composites commonly found in the aerospace industry. The fragments are characterized and reused to produce new CFRP aerospace parts. Structural testing of recycled composite parts revealed a 17% decrease of the mechanical properties compared to the novel material. The combination of these manufacturing and recycling techniques closes the cradle to cradle loop of thermoplastic CFRP.

APA, Harvard, Vancouver, ISO, and other styles

11

Drikakis, Dimitris, Dochan Kwak, and Cetin C. Kiris. "Computational aerodynamics: Advances and challenges." Aeronautical Journal 120, no. 1223 (January 2016): 13–36. http://dx.doi.org/10.1017/aer.2015.2.

Full text

Abstract:

ABSTRACTComputational aerodynamics, which complement more expensive empirical approaches, are critical for developing aerospace vehicles. During the past three decades, computational aerodynamics capability has improved remarkably, following advances in computer hardware and algorithm development. However, most of the fundamental computational capability realised in recent applications is derived from earlier advances, where specific gaps in solution procedures have been addressed only incrementally. The present article presents our view of the state of the art in computational aerodynamics and assessment of the issues that drive future aerodynamics and aerospace vehicle development. Requisite capabilities for perceived future needs are discussed, and associated grand challenge problems are presented.

APA, Harvard, Vancouver, ISO, and other styles

12

Booth, Philip, and Geoffrey E. Wood. "Interest rates are low but are annuities expensive?" Economic Affairs 20, no. 3 (September 2000): 43–44. http://dx.doi.org/10.1111/1468-0270.00238.

Full text

APA, Harvard, Vancouver, ISO, and other styles

13

Šajbanová, Kristína, Jozef Čerňan, and Michal Janovec. "Possibilities of using 3D printing technology in production of aircraft components." AEROjournal 18, no. 2 (2021): 10–15. http://dx.doi.org/10.26552/aer.c.2021.2.2.

Full text

Abstract:

The article provides the reader with a brief overview of the technology of industrial 3D printing used in the manufacturing process of aerospace technology. It includes analyses of the position of 3D printing in the aerospace industry and the forecast of its future development based on the marketing analysis of strengths / weaknesses, opportunities and threats. Many airlines and AMOs (Approved Maintenance Organizations) rely on externally supplied spare parts delivered over long distances. The whole process is expensive and time consuming and means a lost profit for the company. The performed SWOT analysis can therefore ultimately help the AMO manager to re-evaluate their production process in the light of the current innovative and progressive technology of industrial 3D printing.The aim of this work is to point out the existence of innovative 3D printing technology in aerospace production and to emphasize its preferences compared to conventional manufacturing techniques and procedures, thus providing a final perspective on the future of the 3D printing industry and its long-term sustainability

APA, Harvard, Vancouver, ISO, and other styles

14

Kopecki, Grzegorz. "Flight tests and flight data analysis - teaching aerospace engineering students." Global Journal of Information Technology: Emerging Technologies 6, no. 2 (December 1, 2016): 136. http://dx.doi.org/10.18844/gjit.v6i2.939.

Full text

Abstract:

The ability to carry out in-flight tests and to analyse the flight data registered is, in the case of aerospace engineering students, a vital aspect of education. Since aircraft flight tests are very expensive, frequently the funds allocated to them in the process of education are insufficient. The aim of this article is to present a relatively low-cost method of training students to carry out flight tests and to analyse flight data. The method relies on three consecutive steps. At first, simulation tests relying on the mathematical model of an aircraft are carried out. During these simulations, students analyse aircraft behaviour. Next, flight data registered during previously held in-flight tests are analysed. Finally, flight tests are performed by students. As a result, having mastered the ability to analyse real flight data, the students trained will become high-class specialists being able to conduct flight tests and analyse flight data.

APA, Harvard, Vancouver, ISO, and other styles

15

Contreras, José M., Belen Levenfeld, and José M. Torralba. "Coarse and cheap may beat fine and expensive." Metal Powder Report 61, no. 6 (June 2006): 36–41. http://dx.doi.org/10.1016/s0026-0657(06)70657-9.

Full text

APA, Harvard, Vancouver, ISO, and other styles

16

Keane, A. J., and J. P. Scanlan. "Design search and optimization in aerospace engineering." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 365, no. 1859 (May 22, 2007): 2501–29. http://dx.doi.org/10.1098/rsta.2007.2019.

Full text

Abstract:

In this paper, we take a design-led perspective on the use of computational tools in the aerospace sector. We briefly review the current state-of-the-art in design search and optimization (DSO) as applied to problems from aerospace engineering, focusing on those problems that make heavy use of computational fluid dynamics (CFD). This ranges over issues of representation, optimization problem formulation and computational modelling. We then follow this with a multi-objective, multi-disciplinary example of DSO applied to civil aircraft wing design, an area where this kind of approach is becoming essential for companies to maintain their competitive edge. Our example considers the structure and weight of a transonic civil transport wing, its aerodynamic performance at cruise speed and its manufacturing costs. The goals are low drag and cost while holding weight and structural performance at acceptable levels. The constraints and performance metrics are modelled by a linked series of analysis codes, the most expensive of which is a CFD analysis of the aerodynamics using an Euler code with coupled boundary layer model. Structural strength and weight are assessed using semi-empirical schemes based on typical airframe company practice. Costing is carried out using a newly developed generative approach based on a hierarchical decomposition of the key structural elements of a typical machined and bolted wing-box assembly. To carry out the DSO process in the face of multiple competing goals, a recently developed multi-objective probability of improvement formulation is invoked along with stochastic process response surface models (Krigs). This approach both mitigates the significant run times involved in CFD computation and also provides an elegant way of balancing competing goals while still allowing the deployment of the whole range of single objective optimizers commonly available to design teams.

APA, Harvard, Vancouver, ISO, and other styles

17

He, Youwei, Jinju Sun, Peng Song, and Xuesong Wang. "Variable-fidelity expected improvement based efficient global optimization of expensive problems in presence of simulation failures and its parallelization." Aerospace Science and Technology 111 (April 2021): 106572. http://dx.doi.org/10.1016/j.ast.2021.106572.

Full text

APA, Harvard, Vancouver, ISO, and other styles

18

Alpert, Sofiia. "Satellite monitoring problems in the aerospace complex." Ukrainian journal of remote sensing, no. 27 (December 10, 2020): 26–30. http://dx.doi.org/10.36023/ujrs.2020.27.184.

Full text

Abstract:

Задачі підсуNowadays with the rapid development of information technologies, UAV-based Remote Sensing (drone remote sensing) gives a new opportunities for conducting scientific research in a much more detail way. UAVs (unmanned aerial vehicles) give the opportunity to acquire data at sufficiently low cost. They also provide remote data more rapidly than piloted aerial vehicles. Nowadays drones are often used, because application of piloted aerial vehicles can be dangerous, difficult and expensive for some territories. Application of low altitude UAVs give a possibility to achieve images with a very high resolution and sufficient precision. In this article structure and main details of drones were considered. It also was noted, that technologies of UAV-based Remote Sensing are used in different areas.Agricultural drones help to analyze crops, make decisions on how to use the crop information and take the necessary actions to correct the problems. These unmanned aerial vehicles let to see fields from the sky. Agricultural drones are used to help increase crop production and monitor crop growth. Drones and sensors give a detail picture of fields. They can survey the fields periodically. Agricultural drones can reveal many issues such as soil variation, pest infestations and changes in the crops over time. They also show differences between healthy and unhealthy plants. Drones are flied over the crops and help to make decisions on how to proceed given the crop information. Nowadays there is a large capacity for growth in the area of agricultural unmanned aerial vehicles. With technology constantly improving, imaging of the crops will need to improve as well.Drones are used for exploring for minerals and mapping deposit sites, they are used in the oil and gas industry for remote monitoring. Drones can provide information of nature disasters and give help to assess property damage. They help to conduct forest monitoring and to assess plant health. Unmanned aerial vehicles are also used in a military capacity and ecological monitoring. It also was noted, that there is a large capacity for development and improvement of unmanned aerial vehicles.путникового моніторингу в аерокосмічному комплексі

APA, Harvard, Vancouver, ISO, and other styles

19

Khosravani, Mohammad Reza. "Composite Materials Manufacturing Processes." Applied Mechanics and Materials 110-116 (October 2011): 1361–67. http://dx.doi.org/10.4028/www.scientific.net/amm.110-116.1361.

Full text

Abstract:

— Using Composite materials are growing more and more today and we have to use them in possible situation. One of the Composite materials applications is on the Airplane and aero space. Reduction of Airplane weight and more adaptability with nature are examples of benefit of using composite materials in aerospace industries. In this article process of manufacturing of composite materials and specially carbon fiber composite are explained. Advance composite materials are common today and are characterized by the use of expensive, high-performance resin systems and high-strength, high-stiffness fiber reinforcement. The aerospace industry, including military and commercial aircraft of all types, is the major customer for advanced composites. Product range now includes materials for low pressure and low temperature. Some using composite materials in aero space are as follow: Satellite Components, Thin Walled Tubing for Aircraft and Satellites, launch vehicle components and honeycomb structures.

APA, Harvard, Vancouver, ISO, and other styles

20

Hlinka, Jiri, Rostislav Kostial, and Michaela Horpatzka. "Application of enhanced methods for safety assessment of FADEC." Eksploatacja i Niezawodnosc - Maintenance and Reliability 23, no. 1 (January 2, 2021): 63–73. http://dx.doi.org/10.17531/ein.2021.1.7.

Full text

Abstract:

The paper deals with safety and reliability assessment as an integral part of the development process for modern aviation products with potentially critical functions. Focus is on digital engine control units, their development process and tools offering potential savings in otherwise time demanding and expensive safety assessment processes. The paper shows application of several approaches, which together form an innovative way for safety assessment of aerospace products (otherwise strictly limited by regulation procedures). It is focused on practical ways towards reduction of development costs during safety assessment, which do not compromise its comprehensiveness. Described approaches are based on experience from development of numerous aerospace products in last nearly 20 years. As an addition, possibility to further enhance the proposed innovative effect classification by application of FMECA was shown. Possible methods for quantitative assessment using Fuzzy logic and/or multiple-criteria decision analysis were discussed.

APA, Harvard, Vancouver, ISO, and other styles

21

Weston, Nicholas S., and Martin Jackson. "FAST-forge of Titanium Alloy Swarf: A Solid-State Closed-Loop Recycling Approach for Aerospace Machining Waste." Metals 10, no. 2 (February 24, 2020): 296. http://dx.doi.org/10.3390/met10020296.

Full text

Abstract:

Titanium alloys have excellent properties, but components are very expensive due to the high levels of processing required, such as vacuum melting, multi-stage forging, and machining. As a result, forged titanium alloy components are largely exclusive to the aerospace industry, where a high strength-to-weight ratio, corrosion resistance, and excellent fatigue resistance are essential. However, a typical buy-to-fly ratio for such components is approximately 9:1, as much of the forged billet is machined to swarf. The quantity of waste titanium alloy swarf generated is increasing as aircraft orders, and the titanium components contained within them, are increasing. In this paper, waste swarf material has been recycled using the two-step solid-state FAST-forge process, which utilizes field assisted sintering technology (FAST) followed by hot forging. Cleaned Ti-6Al-4V swarf was fully consolidated using the FAST process at sub-transus and super-transus temperatures, followed by hot forging at sub-transus temperatures at different strain rates. It was demonstrated that swarf-derived Ti-6Al-4V FAST billets have equivalent hot forging flow behaviour and resultant microstructures when directly compared to equivalently processed conventional expensive hydride–dehydride powder, and previously reported Kroll-derived melt-wrought material. This demonstrates that titanium swarf is a good quality feedstock for downstream processing. Additionally, FAST-forge is a viable processing route for the closed-loop recycling of machining waste for next-generation components in vehicles and non-aerospace applications, which is game changing for the economics of titanium alloy components.

APA, Harvard, Vancouver, ISO, and other styles

22

Xiao, Jun Min, and Chang Ming Zhao. "Key Technology of 5-Axis NC Programming and High-Speed Milling for Integral Impellers Based on the General Software UG." Advanced Materials Research 314-316 (August 2011): 1633–37. http://dx.doi.org/10.4028/www.scientific.net/amr.314-316.1633.

Full text

Abstract:

Integral impellers are very important parts in the fields of aerospace, shipping and locomotive, whose manufacturing accuracy directly affects performance of key equipments. In developed countries special NC programming software is widely used in order to manufacture integral impellers, the vast majority of enterprises have not special NC programming software of integral impellers owing to expensive cost in China. Key technology of 5-axis NC Programming for integral impellers was solved by using the general software UG and precision machining of integral impellers had been implemented in 5-axis high-speed machining centre.

APA, Harvard, Vancouver, ISO, and other styles

23

Choi, Jun Yong, Do Won Seo, and Jae Kyoo Lim. "Effects of Water Absorption Cycles on Fracture Toughness in Laminated CFRP Composites." Key Engineering Materials 297-300 (November 2005): 2727–32. http://dx.doi.org/10.4028/www.scientific.net/kem.297-300.2727.

Full text

Abstract:

Composite materials have drawn a lot of attention in recent years due to their being in expensive, lightweight and biodegradable. The polyetherimide has been successfully used as an effective toughening modifier for polyfuctional epoxy resins for aerospace use. The material used in this study was solvent-impregnated carbon-fiber fabric reinforced polyetherimide. In this study, effects of water absorption cycles on fracture toughness in carbon fiber reinforced composites (CFRP) have been investigated according to various absorption cycles. As a result, strength of CFRP composite was decreased according to increasing water absorption cycles.

APA, Harvard, Vancouver, ISO, and other styles

24

Fei, Chengwei, Jiongran Wen, Lei Han, Bo Huang, and Cheng Yan. "Optimizable Image Segmentation Method with Superpixels and Feature Migration for Aerospace Structures." Aerospace 9, no. 8 (August 21, 2022): 465. http://dx.doi.org/10.3390/aerospace9080465.

Full text

Abstract:

The lack of high-quality, highly specialized labeled images, and the expensive annotation cost are always critical issues in the image segmentation field. However, most of the present methods, such as deep learning, generally require plenty of train cost and high-quality datasets. Therefore, an optimizable image segmentation method (OISM) based on the simple linear iterative cluster (SLIC), feature migration model, and random forest (RF) classifier, is proposed for solving the small sample image segmentation problem. In the approach, the SLIC is used for extracting the image boundary by clustering, the Unet feature migration model is used to obtain multidimensional superpixels features, and the RF classifier is used for predicting and updating the image segmentation results. It is demonstrated that the proposed OISM has acceptable accuracy, and it retains better target boundary than improved Unet model. Furthermore, the OISM shows the potential for dealing with the fatigue image identification of turbine blades, which can also be a promising method for the effective image segmentation to reveal the microscopic damages and crack propagations of high-performance structures for aeroengine components.

APA, Harvard, Vancouver, ISO, and other styles

25

Tsushima, Natsuki, Kenichi Saitoh, Hitoshi Arizono, and Kazuyuki Nakakita. "Structural and Aeroelastic Studies of Wing Model with Metal Additive Manufacturing for Transonic Wind Tunnel Test by NACA 0008 Example." Aerospace 8, no. 8 (July 25, 2021): 200. http://dx.doi.org/10.3390/aerospace8080200.

Full text

Abstract:

Additive manufacturing (AM) technology has a potential to improve manufacturing costs and may help to achieve high-performance aerospace structures. One of the application candidates would be a wind tunnel wing model. A wing tunnel model requires sophisticated designs and precise fabrications for accurate experiments, which frequently increase manufacturing costs. A flutter wind tunnel testing, especially, requires a significant cost due to strict requirements in terms of structural and aeroelastic characteristics avoiding structural failures and producing a flutter within the wind tunnel test environment. The additive manufacturing technique may help to reduce the expensive testing cost and allows investigation of aeroelastic characteristics of new designs in aerospace structures as needed. In this paper, a metal wing model made with the additive manufacturing technique for a transonic flutter test is studied. Structural/aeroelastic characteristics of an additively manufactured wing model are evaluated numerically and experimentally. The transonic wind tunnel experiment demonstrated the feasibility of the metal AM-based wings in a transonic flutter wind tunnel testing showing the capability to provide reliable experimental data, which was consistent with numerical solutions.

APA, Harvard, Vancouver, ISO, and other styles

26

Santiago, Carolyn Carradero, Bharat Yelamanchi, Jose Angel Diosdado De la Peña, Jeffrey Lamb, Krzysztof Roguski, Filip Turzyński, Ron Faruqui, et al. "Thermoplastic Extrusion Additive Manufacturing of High-Performance Carbon Fiber PEEK Lattices." Crystals 11, no. 12 (November 25, 2021): 1453. http://dx.doi.org/10.3390/cryst11121453.

Full text

Abstract:

Polyetheretherketone (PEEK) has been the focus of substantial additive manufacturing research for two principal reasons: (a) the mechanical performance approaches that of aluminum at relatively high temperatures for thermoplastics and (b) the potential for qualification in both the aerospace and biomedical industries. Although PEEK provides outstanding strength and thermal stability, printing can be difficult due to the high melting point. Recently, high-temperature soluble support has enabled the printing of lattices and stochastic foams with overhanging features in these high-performance carbon fiber thermoplastics, in which density can be optimized to strike a balance between weight and strength to enhance performance in applications such as custom implants or aerospace structures. Although polymer powder bed fusion has long been capable of the combination of these geometries and materials, material extrusion with high-temperature sacrificial support is dramatically less expensive. This research provides a comprehensive mechanical analysis and CT-scan-based dimensional study of carbon fiber PEEK lattice structures enabled with high-temperature support and including model validation.

APA, Harvard, Vancouver, ISO, and other styles

27

Martinsson, Julian, Massimo Panarotto, Michael Kokkolaras, and Ola Isaksson. "EXPLORING THE POTENTIAL OF DIGITAL TWIN-DRIVEN DESIGN OF AERO-ENGINE STRUCTURES." Proceedings of the Design Society 1 (July 27, 2021): 1521–28. http://dx.doi.org/10.1017/pds.2021.413.

Full text

Abstract:

AbstractAs the diversity of customer needs increases within the aerospace industry, so does the need for improved design practices to reduce quality issues downstream. When designing new products, design engineers struggle with applying tolerances to features, which often leads to expensive late design iterations. To mitigate this, one aerospace company is looking to reuse tolerance deviation data yielded during manufacturing in design. In the long term these data could provide the basis for a Digital Twin that can be used for improved product development. This article explores how data from production are used today, what issues prevents such data from being exploited in the design phase, and how they potentially could be used for design purposes in the future. To understand the current situation and identify the untapped potential of production data in design, an interview study was conducted in conjunction with a literature review. In this paper the current situation and primary barriers are presented and a possible path for further research and development is suggested.

APA, Harvard, Vancouver, ISO, and other styles

28

Dasari, Siva Krishna, Abbas Cheddad, and Petter Andersson. "Predictive modelling to support sensitivity analysis for robust design in aerospace engineering." Structural and Multidisciplinary Optimization 61, no. 5 (January 3, 2020): 2177–92. http://dx.doi.org/10.1007/s00158-019-02467-5.

Full text

Abstract:

AbstractThe design of aircraft engines involves computationally expensive engineering simulations. One way to solve this problem is the use of response surface models to approximate the high-fidelity time-consuming simulations while reducing computational time. For a robust design, sensitivity analysis based on these models allows for the efficient study of uncertain variables’ effect on system performance. The aim of this study is to support sensitivity analysis for a robust design in aerospace engineering. For this, an approach is presented in which random forests (RF) and multivariate adaptive regression splines (MARS) are explored to handle linear and non-linear response types for response surface modelling. Quantitative experiments are conducted to evaluate the predictive performance of these methods with Turbine Rear Structure (a component of aircraft) case study datasets for response surface modelling. Furthermore, to test these models’ applicability to perform sensitivity analysis, experiments are conducted using mathematical test problems (linear and non-linear functions) and their results are presented. From the experimental investigations, it appears that RF fits better on non-linear functions compared with MARS, whereas MARS fits well on linear functions.

APA, Harvard, Vancouver, ISO, and other styles

29

Lemanski, S. L., P. M. Weaver, and G. F. J. Hill. "Design of composite helicopter rotor blades to meet given cross-sectional properties." Aeronautical Journal 109, no. 1100 (October 2005): 471–75. http://dx.doi.org/10.1017/s0001924000000889.

Full text

Abstract:

Abstract This paper examines the design of a composite helicopter rotor blade to meet given cross-sectional properties. As with many real-world problems, the choice of objective and design variables can lead to a problem with a non-linear and/or non-convex objective function, which would require the use of stochastic optimisation methods to find an optimum. Since the objective function is evaluated from the results of a finite element analysis of the cross section, the computational expense of using stochastic methods would be prohibitive. It is shown that by choosing appropriate simplified design variables, the problem becomes convex with respect to those design variables. This allows deterministic optimisation methods to be used, which is considerably more computationally efficient than stochastic methods. It is also shown that the design variables can be chosen such that the response of each individual cross-sectional property can be closely modelled by a linear approximation, even though the response of a single objective function to many design parameters is non-linear. The design problem may therefore be reformulated into a number of simultaneous linear equations that are easily solved by matrix methods, thus allowing an optimum to be located with the minimum number of computationally expensive finite element analyses.

APA, Harvard, Vancouver, ISO, and other styles

30

Desmarest, S. Godard, C. Johnston, and P. S. Grant. "Determination of the Creep Properties of Pb-free Solders for Harsh Environments Using Meso-scale Testing." Additional Conferences (Device Packaging, HiTEC, HiTEN, and CICMT) 2012, HITEC (January 1, 2012): 000117–27. http://dx.doi.org/10.4071/hitec-2012-tp23.

Full text

Abstract:

Solder joints in electronic packages are prone to failure due to the evolution of thermal expansion mismatch strains during thermal cycling. The comparatively wide operating temperature range and long lifetimes of aerospace electronics require high reliability solder joints. Since 2006, high reliability industries (aerospace and military amongst others) that are exempt from lead-free RoHS regulation on account of concerns over the reliability of Pb-free solders have found it increasingly difficult and expensive to continue using traditional Sn-Pb-based solders. Hence there is a pressing need to find a suitable alternative that can match the manufacturing and reliability performance of Sn-Pb. There remains a dearth of data for the constitutive behaviour of Pb-free solders under harsh environment scenarios. Unfortunately, conventional test approaches, particularly in the case of creep behaviour which is critical to solder lifetimes, are expensive and time-consuming. High temperature nanoindentation has been recently developed as a quick method for the determination of creep properties of solder alloys. This paper compares and contrasts nanoindentation creep results for bulk Pb-Sn and lead-free solders. However, there are limits to nanoindentation creep, in particular the load-dependence of the technique. A new meso-scale test approach that lies between nanoindentation and bulk creep testing has been developed. Real ball grid arrays using Pb-free solders have been creep tested in the temperature and stress ranges of operating solder joints. High temperature creep constitutive data has been obtained. The technique offers promising time and materials savings in obtaining important mechanical property data for subsequent use in life-prediction models.

APA, Harvard, Vancouver, ISO, and other styles

31

Zhu, Yubo, Jili Rong, Qianqiang Song, and Zhipei Wu. "Research on Reliability Evaluation Method of Aerospace Pyrotechnic Devices Based on Energy Measurement." Applied Sciences 10, no. 22 (November 19, 2020): 8200. http://dx.doi.org/10.3390/app10228200.

Full text

Abstract:

High reliability is the basic requirement of aerospace pyrotechnic devices. Traditional reliability evaluation methods require a lot of tests, which become too expensive; therefore, the small-sample evaluation method is needed to reduce the cost. Using energy as a performance parameter can better reflect the essence of the function of the pyrotechnic device compared to using force. Firstly, this article assumes that the strength obeys the normal distribution, and the stress is a constant; therefore, the reliability evaluation formula based on the t distribution is proposed. Then, taking the pin puller as the research object, four sets of energy measuring devices were developed so as to obtain its performance parameters. Finally, the evaluation results show that the pin puller has a high reliability of 0.9999999765 with a confidence level of 0.995. The reliability method proposed in this paper is a small-sample method for evaluating aerospace pyrotechnic devices, which can greatly reduce the cost of reliability evaluation. Moreover, the energy measuring devices developed in this paper can provide a new way of measuring performance parameters for piston-type pyrotechnic devices.

APA, Harvard, Vancouver, ISO, and other styles

32

Knight, Andrew. "Designing and Testing a Lighter, Simpler, Less-Expensive Liquid-Propellant Pump." Journal of Propulsion and Power 20, no. 1 (January 2004): 141–54. http://dx.doi.org/10.2514/1.9241.

Full text

APA, Harvard, Vancouver, ISO, and other styles

33

Gruszecki, Jan. "ELECTRO‐MECHANICAL ACTUATORS FOR GENERAL AVIATION FLY‐BY‐WIRE AIRCRAFT." Aviation 9, no. 1 (March 31, 2005): 19–25. http://dx.doi.org/10.3846/16487788.2005.9635892.

Full text

Abstract:

A long‐term goal for general aviation aircraft is to reduce or eliminate the use of fluid power systems such as hydraulics from the aircraft. Power‐By‐Wire (PBW) technology seems to be the next major step in the development of aircraft control. In this solution, control power comes directly from the aircraft electrical system to the Electro‐Mechanical Actuator (EMA), which includes the electric motor, controller and gearbox. EMAs have the potential to be more efficient, less complicated, less expensive, and more faults tolerant than actuators based on hydraulic systems.

APA, Harvard, Vancouver, ISO, and other styles

34

Molent, L., and R. Singh. "Using the lead crack framework to reduce durability test duration." Aeronautical Journal 124, no. 1276 (September 24, 2019): 814–20. http://dx.doi.org/10.1017/aer.2019.73.

Full text

Abstract:

ABSTRACTAircraft full-scale fatigue tests are expensive and time-consuming to conduct but are a critical item on the certification path of any aircraft design or modification. This paper outlines a proposal that trades cycling hours for increased detail in the teardown of a metallic test article. A method for determining the equivalent demonstrated crack size (and crack growth curve) at the mandated test life utilising the lead crack framework is demonstrated. It is considered that the test duration can be significantly reduced, whilst still achieving all the desired outcomes of a certification program.

APA, Harvard, Vancouver, ISO, and other styles

35

Srivastava, Ankur, and Andrew J. Meade. "Use of Active Learning to Design Wind Tunnel Runs for Unsteady Cavity Pressure Measurements." International Journal of Aerospace Engineering 2014 (2014): 1–11. http://dx.doi.org/10.1155/2014/218710.

Full text

Abstract:

Wind tunnel tests to measure unsteady cavity flow pressure measurements can be expensive, lengthy, and tedious. In this work, the feasibility of an active machine learning technique to design wind tunnel runs using proxy data is tested. The proposed active learning scheme used scattered data approximation in conjunction with uncertainty sampling (US). We applied the proposed intelligent sampling strategy in characterizing cavity flow classes at subsonic and transonic speeds and demonstrated that the scheme has better classification accuracies, using fewer training points, than a passive Latin Hypercube Sampling (LHS) strategy.

APA, Harvard, Vancouver, ISO, and other styles

36

Yang, M., Z. D. Chang, and J. Chen. "Investigation of flexible free incremental sheet forming (FFISF) process to form Ti6Al4V free-form surface panel at room temperature." IOP Conference Series: Materials Science and Engineering 1270, no. 1 (December 1, 2022): 012086. http://dx.doi.org/10.1088/1757-899x/1270/1/012086.

Full text

Abstract:

Titanium alloy sheet metal shows promising applicability in the aerospace industry with excellent mechanical properties, while its limited room-temperature formability is essential to be improved by thermal-assisted methods, with expensive equipment and much energy consumption. In this work, the flexible free incremental sheet forming process is adopted to manufacture Ti6Al4V free-form surface panel at room temperature. The strain evolution and thickness distribution during this new process are also analysed through finite element methods to reveal the deformation mechanism. Experimental and simulated results show that this process has potential advantages in rapidly fabricating low-ductility sheet metal with complex shapes at room temperature by improving strain and thickness distributions.

APA, Harvard, Vancouver, ISO, and other styles

37

Alabsi, Mohammed, and Travis Fields. "Flight controller learning based on real-time model estimation of a quadrotor aircraft." Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering 233, no. 9 (August 28, 2018): 3298–312. http://dx.doi.org/10.1177/0954410018795524.

Full text

Abstract:

Aircraft prototyping and modeling is usually associated with resource expensive techniques and significant post-flight analysis. The NASA Learn-To-Fly concept targets the replacement of the conventional ground-based aircraft development and prototyping approaches with an efficient real-time paradigm. The work presented herein describes a learning paradigm of a quadcopter unmanned aircraft that utilizes real-time flight data. Closed-loop parameter estimation of a highly collinear model terms such as those found on a quadrotor is challenging. Using phase optimized orthogonal multisine input maneuvers, collinearity of flight data decreases leading to fast and accurate convergence of the Fourier transform regression estimator. The generated models are utilized to reconfigure a nonlinear dynamic inversion controller in normal, failure, and learning testing conditions. Results show highly accurate model estimation in different testing scenarios. Additionally, the nonlinear dynamic inversion controller easily integrates the identified model parameters without any need for gain scheduling or computationally expensive methods. Overall, the proposed technique introduces an efficient integration between real-time modeling and control adaptation utilizing the limited computational power of the quadcopter’s microcomputer.

APA, Harvard, Vancouver, ISO, and other styles

38

Araujo, Eliane Silveira Romagnolli, Jamilson Oliveira Costa, Raphael Oliveira Pires de Lima, and Vinicius André Rodrigues Henriques. "Production of Ti-10V-2Fe-3Al for Aerospace Application from Ti-Al Pre-Alloyed Powder." Materials Science Forum 802 (December 2014): 323–28. http://dx.doi.org/10.4028/www.scientific.net/msf.802.323.

Full text

Abstract:

Titanium is found in its raw form in nature mainly in rutile, ilmenite, and anatase which appears in abundant quantities in the earth crust. However, its extraction through the conventional process is still very expensive. Powder metallurgy has been used as an alternative technique for production of titanium alloys parts due to its low cost compared with conventional melting techniques. The process involves the use of powders under high pressure and temperature. Using this technique, Ti-10V-2Fe-3Al samples were produced from Ti-Al pre-alloyed powder with additions of different contents of aluminum in order to study the influence of aluminum particles on the formation of residual porosity. After cold uniaxial and isostatic pressing and sintering at 1100°C and 1400oC, samples were characterized by SEM (Scanning Electron Microscopy), XRD (X-ray Diffraction), EDS (Energy Dispersive Spectrometry) and density analyses. Sintered samples presented homogeneous microstructure and increased densification due to increased content of Ti-Al pre-alloyed powder.

APA, Harvard, Vancouver, ISO, and other styles

39

Langley, R. S., and N. S. Bardell. "A review of current analysis capabilities applicable to the high frequency vibration prediction of aerospace structures." Aeronautical Journal 102, no. 1015 (May 1998): 287–97. http://dx.doi.org/10.1017/s0001924000065325.

Full text

Abstract:

AbstractMany situations arise in which aerospace structures are subjected to high frequency excitation, in the sense that the wavelength of the induced dynamic response is much shorter than the overall dimensions of the structure. The application of the conventional finite element method to this type of problem faces two difficulties: (i) the short wavelength of the structural deformation requires the use of many elements, which renders the method computationally expensive or even impracticable, and (ii) the response of the structure at high frequencies can be very sensitive to structural detail, and thus response predictions for an ‘ideal’ structure may differ significantly from the performance of the actual system. For a number of years research effort has been directed towards the development of alternative analysis methods for high frequency vibrations, and recent developments in this area are reviewed in the present paper. The methods considered are: (i) hierarchical versions of the finite element method, (ii) the dynamic stiffness method, (iii)periodic structure theory, (iv)statistical energy analysis and (v) wave intensity analysis.

APA, Harvard, Vancouver, ISO, and other styles

40

Laučys, Andrius, Saulius Rudys, Martynas Kinka, Paulius Ragulis, Jurgis Aleksandravičius, Džiugas Jablonskas, Domantas Bručas, Einius Daugėla, and Laurynas Mačiulis. "INVESTIGATION OF DETECTION POSSIBILITY OF UAVS USING LOW COST MARINE RADAR." Aviation 23, no. 2 (May 27, 2019): 48–53. http://dx.doi.org/10.3846/aviation.2019.10320.

Full text

Abstract:

The technologies of Unmanned Aerial Vehicles (UAVs) are fast emerging, but as any other technology, development of UAVs provides not only benefits but also the threats. UAV technologies are developing much faster than means of their control and detection. RADAR technology is one of the means of UAV’s detection. Usually, radars are expensive, and usage of high-power radiation is problematic in many cases. Today’s market provides low cost marine radar working on various principles of operation. Such radar are not optimal, but could be used for UAV detection. Detection possibility of UAVs by FMCW marine radar was investigated by using two types of small UAVs as targets.

APA, Harvard, Vancouver, ISO, and other styles

41

Hunt, D. L., M. Childs, and M. Maina. "QUACC, a novel method for predicting unsteady flows — including propellers and store release." Aeronautical Journal 105, no. 1050 (August 2001): 427–34. http://dx.doi.org/10.1017/s0001924000012409.

Full text

Abstract:

AbstractAerospace designers are increasingly interested in predicting unsteady flowfields such as those associated with store release, rotating propellers etc. However, the cost of performing fully unsteady calculations is usually prohibitively expensive. In order to address this problem for unsteady flows driven by a moving surface, a novel method is presented which calculates the time derivates as an analytic function of the instantaneous flowfield. This allows an accurate solution of the unsteady flow equations to be calculated using a quasi-unsteady approach. The validity of this approach is demonstrated for a store release and a propeller test case. Possible extensions to this method for more complex unsteady flows are presented.

APA, Harvard, Vancouver, ISO, and other styles

42

Liu, Yi, Jiang Chen, Jinxin Cheng, and Hang Xiang. "Aerodynamic Optimization of Transonic Rotor Using Radial Basis Function Based Deformation and Data-Driven Differential Evolution Optimizer." Aerospace 9, no. 9 (September 13, 2022): 508. http://dx.doi.org/10.3390/aerospace9090508.

Full text

Abstract:

The complicated flow conditions and massive design parameters bring two main difficulties to the aerodynamic optimization of axial compressors: expensive evaluations and numerous optimization variables. To address these challenges, this paper establishes a novel fast aerodynamic optimization platform for axial compressors, consisting of a radial basic function (RBF)-based blade parameterization method, a data-driven differential evolution optimizer, and a computational fluid dynamic (CFD) solver. As a versatile interpolation method, RBF is used as the shape parameterization and deformation technique to reduce optimization variables. Aiming to acquire competitive solutions in limited steps, a data-driven evolution optimizer is developed, named the pre-screen surrogate model assistant differential evolution (pre-SADE) optimizer. Different from most surrogate model-assisted evolutionary algorithms, surrogate models in pre-SADE are used to screen the samples, rather than directly estimate them, in each generation to reduce expensive evaluations. The polynomial regression model, Kriging model, and RBF model are integrated in the surrogate model to improve the accuracy. To further save optimization time, the optimizer also integrates parallel task management programs. The aerodynamic optimization of a transonic rotor (NASA Rotor 37) is performed as the validation of the platform. A differential evolution (DE) optimizer and another surrogate model-assisted algorithm, committee-based active learning for surrogate model assisted particle swarm optimization (CAL-SAPSO), are introduced for the comparison runs. After optimization, the adiabatic efficiency, total pressure ratio, and surge margin are, respectively, increased by 1.47%, 1.0%, and 0.79% compared to the initial rotor. In the same limited steps, pre-SADE gets a 0.57% and 0.51% higher rotor adiabatic efficiency than DE and CAL-SAPSO, respectively. With the help of parallel techniques, pre-SADE and DE save half the optimization time compared to CAL-SAPSO. The results verify the effectiveness and the rapidity of the fast aerodynamic optimization platform.

APA, Harvard, Vancouver, ISO, and other styles

43

Adams, Samuel, Chaitali Choudhary, Martine de Cock, Rafael Dowsley, David Melanson, Anderson Nascimento, Davis Railsback, and Jianwei Shen. "Privacy-preserving training of tree ensembles over continuous data." Proceedings on Privacy Enhancing Technologies 2022, no. 2 (March 3, 2022): 205–26. http://dx.doi.org/10.2478/popets-2022-0042.

Full text

Abstract:

Abstract Most existing Secure Multi-Party Computation (MPC) protocols for privacy-preserving training of decision trees over distributed data assume that the features are categorical. In real-life applications, features are often numerical. The standard “in the clear” algorithm to grow decision trees on data with continuous values requires sorting of training examples for each feature in the quest for an optimal cut-point in the range of feature values in each node. Sorting is an expensive operation in MPC, hence finding secure protocols that avoid such an expensive step is a relevant problem in privacy-preserving machine learning. In this paper we propose three more efficient alternatives for secure training of decision tree based models on data with continuous features, namely: (1) secure discretization of the data, followed by secure training of a decision tree over the discretized data; (2) secure discretization of the data, followed by secure training of a random forest over the discretized data; and (3) secure training of extremely randomized trees (“extra-trees”) on the original data. Approaches (2) and (3) both involve randomizing feature choices. In addition, in approach (3) cut-points are chosen randomly as well, thereby alleviating the need to sort or to discretize the data up front. We implemented all proposed solutions in the semi-honest setting with additive secret sharing based MPC. In addition to mathematically proving that all proposed approaches are correct and secure, we experimentally evaluated and compared them in terms of classification accuracy and runtime. We privately train tree ensembles over data sets with thousands of instances or features in a few minutes, with accuracies that are at par with those obtained in the clear. This makes our solution more efficient than the existing approaches, which are based on oblivious sorting.

APA, Harvard, Vancouver, ISO, and other styles

44

Liu, Xueshu, Junhao Chang, Yuxing Yang, Yiqi Wang, Yongjie Bao, and Hang Gao. "Evaluation of Assembly Gap from 3D Laser Measurements via FEA Simulation." International Journal of Aerospace Engineering 2018 (October 1, 2018): 1–7. http://dx.doi.org/10.1155/2018/4303105.

Full text

Abstract:

Due to the compliance and geometrical defects of composite parts, gaps exist between assembly components after the preassembly. Assembly requirements impose to fill these gaps to eliminate any unexpected internal stresses. Although it is identified as a problematic and expensive nonadded value stage, a gap measurement is still needed. This paper develops a numerical process for gap prediction before the assembly step. After the assembly components are scanned in a specified configuration, finite element meshes are created using the scanned data and the shape variations of each component caused by constraints and forces in different configurations are evaluated by finite element analysis. Assembly gaps are finally assessed by assembling the simulated preassembly shapes of all components. The feasibility of the proposed method is proved by an experiment.

APA, Harvard, Vancouver, ISO, and other styles

45

March, A., K. Willcox, and Q. Wang. "Gradient-based multifidelity optimisation for aircraft design using Bayesian model calibration." Aeronautical Journal 115, no. 1174 (December 2011): 729–38. http://dx.doi.org/10.1017/s0001924000006473.

Full text

Abstract:

Abstract Optimisation of complex systems frequently requires evaluating a computationally expensive high-fidelity function to estimate a system metric of interest. Although design sensitivities may be available through either direct or adjoint methods, the use of formal optimisation methods may remain too costly. Incorporating low-fidelity performance estimates can substantially reduce the cost of the high-fidelity optimisation. In this paper we present a provably convergent multifidelity optimisation method that uses Cokriging Bayesian model calibration and first-order consistent trust regions. The technique is compared with a single-fidelity sequential quadratic programming method and a conventional first-order trust-region method on both a two-dimensional structural optimisation and an aerofoil design problem. In both problems adjoint formulations are used to provide inexpensive sensitivity information.

APA, Harvard, Vancouver, ISO, and other styles

46

Goraj, Zdobyslaw Jan, Marek Malinowski, and Andrzej Frydrychewicz. "Design of novel aerial jet target." Aircraft Engineering and Aerospace Technology 89, no. 4 (July 3, 2017): 511–19. http://dx.doi.org/10.1108/aeat-10-2016-0174.

Full text

Abstract:

Purpose This paper aims to present and discuss the requirements for flying targets which sometimes are contradictory to each other and to perform a trade-off analysis before the design activity is started. It also aims to demonstrate conceptual and preliminary design processes using a practical example of PW-61 configuration and to show how results of experimental flight tests using a scaled flying target will be described and analyzed before manufacturing the full scale flying target. Design/methodology/approach An important part of the paper consists of the selection of tailplane configuration of the flying target UAV to protect some expensive on-board systems against serious damages and to obtain a sufficient dynamic stability, independently of the amount of the petrol in fuel tank. Inverted V-tail, U-tail and H-tail configurations were considered and compared both, theoretically and in-flight experiments. Findings Flight dynamics models and associated computational procedures were useful both in a preliminary design phase and during the final assessment of the configuration after flight tests. Selection of the tailplane configuration for the flying target UAV is very important to protect some expensive on-board systems against serious damages and to obtain a sufficient dynamic stability, independent of the amount of the petrol in fuel tank. Practical implications Flying targets should be speedy, maneuverable, cheap, easy in deployment and multi-recoverable (if not destroyed by live ammunition), must have relatively low take-off weight and an endurance of at least 1 h. This paper can be useful for proper selection of requirements and preliminary design parameters to make the design process more economically effective. Originality/value This paper presents very efficient methods of assessing the design parameters of flying targets, especially in an early stage of the design process. Stability computations are performed based on equations of motion and are supplemented by flight tests using the scaled flying models. It can be considered as an original, not typical, but very practical approach because it delivers lots of data in the early design stages at relatively low cost.

APA, Harvard, Vancouver, ISO, and other styles

47

Müller, Jakob R., Massimo Panarotto, and Ola Isaksson. "Connecting Functional and Geometrical Representations to Support the Evaluation of Design Alternatives for Aerospace Components." Proceedings of the Design Society: International Conference on Engineering Design 1, no. 1 (July 2019): 1423–32. http://dx.doi.org/10.1017/dsi.2019.148.

Full text

Abstract:

AbstractNovel product concepts are often down-selected in favour of the incremental development of available designs. This can be attributed to the fact that for the development of a new product, simulations and analysis based on high-fidelity CAD models are required, which are expensive to create. To solve this problem, the use of a function model (FM) as intermediate step between ideation and embodiment is suggested.The approach has been examined in a case study with an aerospace company for the development of a turbine rear assembly, using multiple workshops and interviews with practitioners from the company. A multitude of novel solutions, even extending the functionality of the legacy design, were captured. The FM approach proved to support the representation, analysis, and configuration of 102 different concepts. Although supported by the FM model, the embodiment still showed to be a bottle neck for further development. The subsequent interviews with practitioners showed that the benefits of the approach were seen, but experienced as too complex.Further work will concern a more systematic connection between the FM and CAD model, in order to automate of the embodiment process.

APA, Harvard, Vancouver, ISO, and other styles

48

Ge, Wenyi, Zhitao Wang, Guigui Wang, Shihan Tan, and Jianwei Zhang. "Remote Sensing Image Super-Resolution for the Visual System of a Flight Simulator: Dataset and Baseline." Aerospace 8, no. 3 (March 15, 2021): 76. http://dx.doi.org/10.3390/aerospace8030076.

Full text

Abstract:

High-resolution remote sensing images are the key data source for the visual system of a flight simulator for training a qualified pilot. However, due to hardware limitations, it is an expensive task to collect spectral and spatial images at very high resolutions. In this work, we try to tackle this issue with another perspective based on image super-resolution (SR) technology. First, we present a new ultra-high-resolution remote sensing image dataset named Airport80, which is captured from the airspace near various airports. Second, a deep learning baseline is proposed by applying the generative and adversarial mechanism, which is able to reconstruct a high-resolution image during a single image super-resolution. Experimental results for our benchmark demonstrate the effectiveness of the proposed network and show it has reached satisfactory performances.

APA, Harvard, Vancouver, ISO, and other styles

49

Bakunowicz, Jerzy, and Tomasz Kopecki. "GLOBAL ANALYSIS OF THE AIRCRAFT STRUCTURE AND ITS APPLICATION TO THE PRELIMINARY DESIGN STAGE." Aviation 9, no. 3 (September 30, 2005): 29–35. http://dx.doi.org/10.3846/16487788.2005.9635908.

Full text

Abstract:

Modern aircraft safety depends on sufficient strength and rigidity of the structure. This must sustain with lightest possible weight, because any excess mass has not only detrimental effect upon the performance but also is significant economic factor. The most rational way to achieve the proper structure seems to be global analysis commenced in the preliminary design stage already. The analysis outcomes provide base for local analysis of the details led parallel. Any revisions more or less relevant can be made in the numerical model with very expensive prototype changes avoiding. The paper illustrates efficiency of the airframe structure global analysis. As examples the aircrafts still in service but designed without computer application were chosen. The finite elements numerical model of each was created and some critical in-flight load cases were simulated.

APA, Harvard, Vancouver, ISO, and other styles

50

Miranda, Francisco. "Guidance Stabilization of Satellites Using the Geomagnetic Field." International Journal of Aerospace Engineering 2012 (2012): 1–9. http://dx.doi.org/10.1155/2012/231935.

Full text

Abstract:

In the last years the small satellites have played an important role in the technological development. The attractive short period of design and low cost of them and the capacity to solve problems that are usually considered as problems to big and expensive spacecrafts lead us to study the control problem of these satellites. Active three-axis magnetic attitude stabilization of a low Earth orbit satellite is considered in this work. The control is created by interaction between the magnetic moment generated by magnetorquers mounted on the satellite body and the geomagnetic field. This problem is quite complex and difficult to solve. To overcome this difficulty guidance control is considered, where we use ε-strategies introduced by Pontryagin in the frame of differential games theory. Qualitative analysis and results of numerical simulation are presented.

APA, Harvard, Vancouver, ISO, and other styles

Journal articles on the topic 'Expensive aerospace'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles