Aerodynamic robust optimization of flying wing aircraft based on interval method

2017 ◽  
Vol 89 (3) ◽  
pp. 491-497 ◽  
Author(s):  
Yalin Pan ◽  
Jun Huang ◽  
Feng Li ◽  
Chuxiong Yan

Purpose The purpose of this paper is to propose a robust optimization strategy to deal with the aerodynamic optimization issue, which does not need a large sum of information on the uncertainty of input parameters. Design/methodology/approach Interval numbers were adopted to describe the uncertain input, which only requires bounds and does not necessarily need probability distributions. Based on the method, model outputs were also regarded as intervals. To identify a better solution, an order relation was used to rank interval numbers. Findings Based on intervals analysis method, the uncertain optimization problem was transformed into nested optimization. The outer optimization was used to optimize the design vector, and inner optimization was used to compute the interval of model outputs. A flying wing aircraft was used as a basis for uncertainty optimization through the suggested optimization strategy, and optimization results demonstrated the validity of the method. Originality/value In aircraft conceptual design, the uncertain information of design parameters are often insufficient. Interval number programming method used for uncertainty analysis is effective for aerodynamic robust optimization for aircraft conceptual design.

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Ramazan Özkan ◽  
Mustafa Serdar Genç

Purpose Wind turbines are one of the best candidates to solve the problem of increasing energy demand in the world. The aim of this paper is to apply a multi-objective structural optimization study to a Phase II wind turbine blade produced by the National Renewable Energy Laboratory to obtain a more efficient small-scale wind turbine. Design/methodology/approach To solve this structural optimization problem, a new Non-Dominated Sorting Genetic Algorithm (NSGA-II) was performed. In the optimization study, the objective function was on minimization of mass and cost of the blade, and design parameters were composite material type and spar cap layer number. Design constraints were deformation, strain, stress, natural frequency and failure criteria. ANSYS Composite PrepPost (ACP) module was used to model the composite materials of the blade. Moreover, fluid–structure interaction (FSI) model in ANSYS was used to carry out flow and structural analysis on the blade. Findings As a result, a new original blade was designed using the multi-objective structural optimization study which has been adapted for aerodynamic optimization, the NSGA-II algorithm and FSI. The mass of three selected optimized blades using carbon composite decreased as much as 6.6%, 11.9% and 14.3%, respectively, while their costs increased by 23.1%, 29.9% and 38.3%. This multi-objective structural optimization-based study indicates that the composite configuration of the blade could be altered to reach the desired weight and cost for production. Originality/value ACP module is a novel and advanced composite modeling technique. This study is a novel study to present the NSGA-II algorithm, which has been adapted for aerodynamic optimization, together with the FSI. Unlike other studies, complex composite layup, fiber directions and layer orientations were defined by using the ACP module, and the composite blade analyzed both aerodynamic pressure and structural design using ACP and FSI modules together.


2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Amir Moslemi ◽  
Mahmood Shafiee

PurposeIn a multistage process, the final quality in the last stage not only depends on the quality of the task performed in that stage but is also dependent on the quality of the products and services in intermediate stages as well as the design parameters in each stage. One of the most efficient statistical approaches used to model the multistage problems is the response surface method (RSM). However, it is necessary to optimize each response in all stages so to achieve the best solution for the whole problem. Robust optimization can produce very accurate solutions in this case.Design/methodology/approachIn order to model a multistage problem, the RSM is often used by the researchers. A classical approach to estimate response surfaces is the ordinary least squares (OLS) method. However, this method is very sensitive to outliers. To overcome this drawback, some robust estimation methods have been presented in the literature. In optimization phase, the global criterion (GC) method is used to optimize the response surfaces estimated by the robust approach in a multistage problem.FindingsThe results of a numerical study show that our proposed robust optimization approach, considering both the sum of square error (SSE) index in model estimation and also GC index in optimization phase, will perform better than the classical full information maximum likelihood (FIML) estimation method.Originality/valueTo the best of the authors’ knowledge, there are few papers focusing on quality-oriented designs in the multistage problem by means of RSM. Development of robust approaches for the response surface estimation and also optimization of the estimated response surfaces are the main novelties in this study. The proposed approach will produce more robust and accurate solutions for multistage problems rather than classical approaches.


2018 ◽  
Vol 90 (7) ◽  
pp. 1128-1135 ◽  
Author(s):  
Raghu Chaitanya Munjulury ◽  
Ingo Staack ◽  
Adrián Sabaté López ◽  
Petter Krus

Purpose This paper aims to present a knowledge-based fuel system, implementation and application, oriented towards its use in aircraft conceptual design. Design/methodology/approach Methodology and software tools oriented to knowledge-based engineering applications (MOKA) is used as a foundation for the implementation and integration of fuel systems. Findings Including fuel systems earlier in the design process creates an opportunity to optimize it and obtain better solutions by allocating suitable locations in an aircraft, thereby reflecting on the centre of gravity of the aircraft. Research limitations/implications All geometries are symbolic, representing a space allocation inside the aircraft for the fuel system. A realistic representation of the real components could be realized in detail design. Practical implications Fuel weight is a significant part of take-off weight and decisive in aircraft sizing and range estimations. The three-dimensional geometry provides a better estimation of the volume that is available to allocate the necessary entities. It also provides fast measures for weight and balance, fuel capacity, relative tank positions and a first estimation of piping length. Originality/value Fuel systems appear early in the design process, as they are involved in several first estimations. By using a knowledge-based engineering approach, several alternatives can be visualized and estimated in the conceptual design process. Furthermore, using the weights and centre of gravity at different angles of pitch and roll of each fuel tank, the aircraft could be optimized for handling qualities by using automatically generated system simulation models.


Author(s):  
Aleksandr Alekseevich Gorbunov ◽  
Aleksei Dmitrievich Pripadchev ◽  
Valeriy Vladimirovich Elagin ◽  
Aleksandr Gennadievich Magdin ◽  
Elena Mihailovna Ezerskaya

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Hasim Kafali ◽  
Göksel Keskin

Purpose The purpose of this paper is to create a conceptual design a bird-inspired unmanned aerial vehicle (UAV) that can stay in the air for a long time while this design influences the species near the airport with predator appearance. To achieve that goal, reverse engineering methods took into account to find out optimal parameter, and effective bird species were examined to be taken as an example. Design/methodology/approach Design parameters were determined according to the behaviour of bird species in the region and their natural enemies. Dalaman airport where is located near the fresh water supplies and sea, was chosen as the area to run. To keep such birds away from the airport and to prevent potential incidents, information from animal behaviour studies is enormously important. According to Tinbergen, chicken and gees reacted to all short-necked birds because they thought they were predators. The entire method is based on information from these data, along with reverse engineering principles. Findings UAV can remain in the air for more than 5 min when the engine stops at an altitude of 200 m. Also, when the UAV loses altitude of 100 m, it can cover a distance of about 2 m with the 19.8-glide ratio. Moreover, 380 KV brushless electric motor can provide 5.2 kg thrust force with 17 × 8-inch folding propeller which means 1.3 thrust to weight ratio (T/W). This engine and propeller combination work up to 12 min at maximum power with 7000 mAh lipo-battery. The UAV can climb more than 40 min at 0.2 T/W ratio. Research limitations/implications While bird-inspired UAV trials have just begun, general ornithopter studies have taken smaller birds as their source because this is the limit of the flapping wing, one of the largest birds modelled in this study. Thus, it is inevitable the UAV influences other birds in the area. In addition, this bird’s inherent flight behaviour, such as soaring, ridge lifting and gliding, will increase its credibility. Owing to size similarity with UAV systems, reverse engineering methods worked well in the design. Practical implications Some of the specialist try to fly trained falcon in airport as an alternative method. This study focussed on the design of a bird-inspired UAV by optimizing the glide performance, both for scare the other birds around the airport and for the observation of birds in the vicinity and for the identification of bird species. Social implications As this type of work has been proven to reduce the risk of bird strikes, the sense of flight safety on society will increase. Originality/value Researchers and companies generally work on flapping wing models for related subjects. However, these products are kind of model of the Falconiformes species which don’t have too much influence on big birds. For this reason, the authors took account of Imperial eagle’s specifications. These birds perform long soaring flights while seeking for prey like the glider design. So, the authors think it is a new approach for designing UAV for preventing bird-strike.


2019 ◽  
Vol 30 (9) ◽  
pp. 4219-4239
Author(s):  
Grégory Millot ◽  
Olivier Scholz ◽  
Saïd Ouhamou ◽  
Mathieu Becquet ◽  
Sébastien Magnabal

PurposeThe paper deals with research activities to develop optimization workflows implying computational fluid dynamics (CFD) modelling. The purpose of this paper is to present an industrial and fully-automated optimal design tool, able to handle objectives, constraints, multi-parameters and multi-points optimization on a given CATIA CAD. The work is realized on Rapid And CostEffective Rotorcraft compound rotorcraft in the framework of the Fast RotorCraft Innovative Aircraft Demonstrator Platform (IADP) within the Clean Sky 2 programme.Design/methodology/approachThe proposed solution relies on an automated CAD-CFD workflow called through the optimization process based on surrogate-based optimization (SBO) techniques. The SBO workflow has been specifically developed.FindingsThe methodology is validated on a simple configuration (bended pipe with two parameters). Then, the process is applied on a full compound rotorcraft to minimize the flow distortion at the engine entry. The design of the experiment and the optimization loop act on seven design parameters of the air inlet and for each individual the evaluation is performed on two operation points, namely, cruise flight and hover case. Finally, the best design is analyzed and aerodynamic performances are compared with the initial design.Originality/valueThe adding value of the developed process is to deal with geometric integration conflicts addressed through a specific CAD module and the implementation of a penalty function method to manage the unsuccessful evaluation of any individual.


2021 ◽  
Vol 1 ◽  
pp. 731-740
Author(s):  
Giovanni Formentini ◽  
Claudio Favi ◽  
Claude Cuiller ◽  
Pierre-Eric Dereux ◽  
Francois Bouissiere ◽  
...  

AbstractOne of the most challenging activity in the engineering design process is the definition of a framework (model and parameters) for the characterization of specific processes such as installation and assembly. Aircraft system architectures are complex structures used to understand relation among elements (modules) inside an aircraft and its evaluation is one of the first activity since the conceptual design. The assessment of aircraft architectures, from the assembly perspective, requires parameter identification as well as the definition of the overall analysis framework (i.e., mathematical models, equations).The paper aims at the analysis of a mathematical framework (structure, equations and parameters) developed to assess the fit for assembly performances of aircraft system architectures by the mean of sensitivity analysis (One-Factor-At-Time method). The sensitivity analysis was performed on a complex engineering framework, i.e. the Conceptual Design for Assembly (CDfA) methodology, which is characterized by level, domains and attributes (parameters). A commercial aircraft cabin system was used as a case study to understand the use of different mathematical operators as well as the way to cluster attributes.


2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Chun-Teck Lye ◽  
Tuan-Hock Ng ◽  
Kwee-Pheng Lim ◽  
Chin-Yee Gan

PurposeThis study uses the unique setting of unusual market activity (UMA) replies to examine the market reaction and the effects of disclosure and investor protection amid information uncertainty.Design/methodology/approachA total of 1527 hand-collected UMA replies from the interlinked stock exchanges of Indonesia, Malaysia, Thailand and Singapore for the period of 2015–2017 were analysed using event study and Heckman two-step methods with market and matched control firm benchmarks.FindingsThe overall results support the uncertain information hypothesis. The UMA replies with new information were also found to reduce information uncertainty, but not information asymmetry, and they are complementary to investor protection in enhancing abnormal returns. The overall finding suggests that the UMA public query system can be an effective market intervention mechanism in improving information certainty and efficiency.Research limitations/implicationsThis study provides insight on the effects of news replies and investor protection on abnormal returns, and support for the uncertain information hypothesis. The finding is useful to policymakers and stock exchanges as they seek to understand how to alleviate investors' anxiety and to create an informationally efficient market. Nevertheless, this study is limited by the extensiveness of the hand-collected UMA replies and also the potential issue of simultaneity-induced endogeneity.Originality/valueThis study uses UMA replies and cross-country data taking into account the effects of market surroundings such as information uncertainty and the level of investor protection on market reaction.


Sign in / Sign up

Export Citation Format

Share Document