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Article
Publication date: 14 March 2023

Jiahao Zhu, Guohua Xu and Yongjie Shi

This paper aims to develop a new method of fuselage drag optimization that can obtain results faster than the conventional methods based on full computational fluid dynamics (CFD…

120

Abstract

Purpose

This paper aims to develop a new method of fuselage drag optimization that can obtain results faster than the conventional methods based on full computational fluid dynamics (CFD) calculations and can be used to improve the efficiency of preliminary design.

Design/methodology/approach

An efficient method for helicopter fuselage shape optimization based on surrogate-based optimization is presented. Two numerical simulation methods are applied in different stages of optimization according to their relative advantages. The fast panel method is used to calculate the sample data to save calculation time for a large number of sample points. The initial solution is obtained by combining the Kriging surrogate model and the multi-island genetic algorithm. Then, the accuracy of the solution is determined by using the infill criteria based on CFD corrections. A parametric model of the fuselage is established by several characteristic sections and guiding curves.

Findings

It is demonstrated that this method can greatly reduce the calculation time while ensuring a high accuracy in the XH-59A helicopter example. The drag coefficient of the optimized fuselage is reduced by 13.3%. Because of the use of different calculation methods for samples, this novel method reduces the total calculation time by almost fourfold compared with full CFD calculations.

Originality/value

To the best of the authors’ knowledge, this is the first study to provide a novel method of fuselage drag optimization by combining different numerical simulation methods. Some suggestions on fuselage shape optimization are given for the XH-59A example.

Details

Aircraft Engineering and Aerospace Technology, vol. 95 no. 7
Type: Research Article
ISSN: 1748-8842

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Article
Publication date: 31 July 2021

Niu Zijie, Zhang Peng, Yongjie Cui and Zhang Jun

Omnidirectional mobile platforms are still plagued by the problem of heading deviation. In four-Mecanum-wheel systems, this problem arises from the phenomena of dynamic imbalance…

308

Abstract

Purpose

Omnidirectional mobile platforms are still plagued by the problem of heading deviation. In four-Mecanum-wheel systems, this problem arises from the phenomena of dynamic imbalance and slip of the Mecanum wheels while driving. The purpose of this paper is to analyze the mechanism of omnidirectional motion using Mecanum wheels, with the aim of enhancing the heading precision. A proportional-integral-derivative (PID) setting control algorithm based on a radial basis function (RBF) neural network model is introduced.

Design/methodology/approach

In this study, the mechanism of omnidirectional motion using Mecanum wheels is analyzed, with the aim of enhancing the heading precision. A PID setting control algorithm based on an RBF neural network model is introduced. The algorithm is based on a kinematics model for an omnidirectional mobile platform and corrects the driving heading in real time. In this algorithm, the neural network RBF NN2 is used for identifying the state of the system, calculating the Jacobian information of the system and transmitting information to the neural network RBF NN1.

Findings

The network RBF NN1 calculates the deviations ?Kp, ?Ki and ?Kd to regulate the three coefficients Kp, Ki and Kd of the heading angle PID controller. This corrects the driving heading in real time, resolving the problems of low heading precision and unstable driving. The experimental data indicate that, for a externally imposed deviation in the heading angle of between 34º and ∼38°, the correction time for an omnidirectional mobile platform applying the algorithm during longitudinal driving is reduced by 1.4 s compared with the traditional PID control algorithm, while the overshoot angle is reduced by 7.4°; for lateral driving, the correction time is reduced by 1.4 s and the overshoot angle is reduced by 4.2°.

Originality/value

In this study, the mechanism of omnidirectional motion using Mecanum wheels is analyzed, with the aim of enhancing the heading precision. A PID setting control algorithm based on an RBF neural network model is introduced. The algorithm is based on a kinematics model for an omnidirectional mobile platform and corrects the driving heading in real time. In this algorithm, the neural network RBF NN2 is used for identifying the state of the system, calculating the Jacobian information of the system and transmitting information to the neural network RBF NN1. The method is innovative.

Details

Industrial Robot: the international journal of robotics research and application, vol. 49 no. 1
Type: Research Article
ISSN: 0143-991X

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Article
Publication date: 1 September 2016

Ren Hong, Du Yongjie, Cai Weiguang, Ma Xianrui, Wang Peng, Qin Beibei and Chen Mingman

With high-speed urbanization and strict requirements on energy conservation and environmental protection, eco-city has become the priority of urban development in China…

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Abstract

With high-speed urbanization and strict requirements on energy conservation and environmental protection, eco-city has become the priority of urban development in China. Governments of all levels promote various eco-city planning schemes within a short term, but most schemes are characterized by randomness and subjectivity. To solve the lack of scientific pre-implementation evaluation for eco-city planning and improve eco-city construction quality, a systematic analysis is conducted in this study from three dimensions, namely, eco-city planning scheme, operating mechanism, and guarantee measures. A 3D evaluation model for eco-city planning is constructed through index selection. Schemes are ranked comprehensively with the distance measure method, and projection analysis is performed with the four-grid evaluation screen. Finally, the 3D evaluation model is applied to evaluate eco-city planning for Shenzhen, Chongqing, and Weifang. Results show that the model can be used to evaluate eco-city planning schemes effectively and comprehensively and offers targeted optimization suggestions in accordance with the evaluation results. Construction of the 3D evaluation model of eco-city planning based on the distance measure to determine the reasonability of eco-city planning reduces the institutional and social costs of eco-city planning practices.

Details

Open House International, vol. 41 no. 3
Type: Research Article
ISSN: 0168-2601

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Article
Publication date: 29 January 2021

Hai Tan, Yanbao Guo, Junqiang Wang, Deguo Wang and Yongjie Cui

The purpose of this study is to investigate the influence of additive particle size on the anti-corrosion behaviors of polyurethane (PU) coating.

157

Abstract

Purpose

The purpose of this study is to investigate the influence of additive particle size on the anti-corrosion behaviors of polyurethane (PU) coating.

Design/methodology/approach

The graphite (Gr) and poly-graphite (PGr) were used as large size additive and small size additive, respectively. The immersion test and electrochemical test were used to study the corrosion behaviors.

Findings

In the immersion test, the surface of the bare steel sample was corroded uniformly. However, for the steel samples with coatings, the surfaces were corroded locally. This phenomenon showed that the coating can isolate artificial sea-water and samples and then decreased the corrosion rate. Furthermore, the most severe corrosion was observed on the sample with the Gr/PU coating compared with other anti-corrosion coatings. The results of the electrochemical measurements indicated that the corrosion rate of the sample with PGr/PU coating was approximately two times lower than that of the sample with the Gr/PU coating and the sample with PGr/PU coating was hardest to be corroded.

Originality/value

To have a more objective and direct recognition of the particle size effect on the coating quality.

Details

Anti-Corrosion Methods and Materials, vol. 68 no. 1
Type: Research Article
ISSN: 0003-5599

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Article
Publication date: 8 April 2024

Fukang Yang, Wenjun Wang, Yongjie Yan and YuBing Dong

Polyethylene terephthalate (PET) as a fiber molding polymer is widely used in aerospace, electrical and electronic, clothing and other fields. The purpose of this study is to…

129

Abstract

Purpose

Polyethylene terephthalate (PET) as a fiber molding polymer is widely used in aerospace, electrical and electronic, clothing and other fields. The purpose of this study is to improve the thermal insulation performance of polyethylene terephthalate (PET), the SiO2 aerogel/PET composites slices and fibers were prepared, and the effects of the SiO2 aerogel on the morphology, structure, crystallization property and thermal conductivity of the SiO2 aerogel/PET composites slices and their fibers were systematically investigated.

Design/methodology/approach

The mass ratio of purified terephthalic acid and ethylene glycol was selected as 1:1.5, which was premixed with Sb2O3 and the corresponding mass of SiO2 aerogel, and SiO2 aerogel/PET composites were prepared by direct esterification and in-situ polymerization. The SiO2 aerogel/PET composite fibers were prepared by melt-spinning method.

Findings

The results showed that the SiO2 aerogel was uniformly dispersed in the PET matrix. The thermal insulation coefficient of PET was significantly reduced by the addition of SiO2 aerogel, and the thermal conductivity of the 1.0 Wt.% SiO2 aerogel/PET composites was reduced by 75.74 mW/(m · K) compared to the pure PET. The thermal conductivity of the 0.8 Wt.% SiO2 aerogel/PET composite fiber was reduced by 46.06% compared to the pure PET fiber. The crystallinity and flame-retardant coefficient of the SiO2 aerogel/PET composite fibers showed an increasing trend with the addition of SiO2 aerogel.

Research limitations/implications

The SiO2 aerogel/PET composite slices and their fibers have good thermal insulation properties and exhibit good potential for application in the field of thermal insulation, such as warm clothes. In today’s society where the energy crisis is becoming increasingly serious, improving the thermal insulation performance of PET to reduce energy loss will be of great significance to alleviate the energy crisis.

Originality/value

In this study, SiO2 aerogel/PET composite slices and their fibers were prepared by an in situ polymerization process, which solved the problem of difficult dispersion of nanoparticles in the matrix and the thermal conductivity of PET significantly reduced.

Details

Pigment & Resin Technology, vol. 54 no. 2
Type: Research Article
ISSN: 0369-9420

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Article
Publication date: 3 October 2024

Gang Wei, Zhiyuan Mu, Weihao Feng, Yongjie Qi and Binglai Guo

The aim of this study is to investigate the horizontal displacement effects of foundation pit excavation on adjacent metro stations and shield tunnel composite structures. It…

54

Abstract

Purpose

The aim of this study is to investigate the horizontal displacement effects of foundation pit excavation on adjacent metro stations and shield tunnel composite structures. It seeks to develop a theoretical calculation method capable of accurately assessing these engineering impacts, aiming to provide practical assistance for engineering applications.

Design/methodology/approach

This study introduces a model for shield tunnel segments incorporating rotation and misalignment, considering the constraints of metro stations. It establishes a displacement model for tunnel-station combinations during foundation pit excavation, deriving a formula for calculating station-proximal tunnel horizontal displacements. The method's accuracy is validated against field data from three engineering cases. The research also explores variations in tunnel displacement, inter-ring shear force, misalignment and rotation angle under different spatial relationships between pits, tunnels and stations.

Findings

This study models uneven deformation between stations and tunnels due to bending stiffness and shear constraints. It enhances the misalignment model with station-induced shear effects and introduces coefficients for their mutual interaction. Results show varied responses based on pit-station-tunnel positioning: minimal displacement near pit edges (coefficients around 0.1) and significant effects near pit centers (coefficients from 0.4 to 0.5). “Whip effect” from station constraints affects tunnel displacement, shear force, misalignment and rotation, with fluctuations decreasing with distance from excavation areas.

Originality/value

This study demonstrates significant originality and value. It introduces a novel displacement model for tunnel-station combinations considering station constraints, addressing theoretical calculations of horizontal displacement effects from foundation pit excavation on metro stations and shield tunnel structures. Through validation with field data and parameter studies, the concept of influence coefficients is proposed, offering insights into variations in structural responses under different spatial relationships. This research provides crucial technical support and decision-making guidance for optimizing designs and facilitating practical construction in similar engineering projects.

Details

Engineering Computations, vol. 41 no. 10
Type: Research Article
ISSN: 0264-4401

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