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Li G.-Y.,Shanghai JiaoTong University | Li G.-Y.,Shanghai Aircraft Customer Service Co. | Li X.-P.,Shanghai JiaoTong University | Li X.-P.,Shanghai Aircraft Customer Service Co. | And 4 more authors.
Microelectronic Engineering | Year: 2012

The superhydrophobic behavior has attracted many researchers' attention. The conventional method of obtaining superhydrophobicity involves the combination of the coating of low-surface-energy material and constructing roughness on smooth surface. According to Cassie-Baxter law, this paper proposes a method that the superhydrophobicity could be obtained on structured hydrophilic surface without any coating of low-surface-energy material. Based on the surface micromachining technology, the superhydrophobic behavior has been achieved by the fabrication of micro-nickel cylinder array. It has been proved by the experiments that the micro-cylinder arrays exhibit superhydrophobic behavior; the maximum contact angle (CA) between the array and the water droplet can be up to 155°, while the intrinsic CA of smooth nickel surface is 82°. By controlling the parameters of cylinders (diameter/height/spacing), we investigated the relationship between the hydrophobicity and the above parameters. It proved that the spacing height ratio contributed to the transition from Cassie's model to Wenzel's, which was the main cause of disappearance of superhydrophobicity. © 2012 Elsevier B.V. All rights reserved.


Xu J.,Beihang University | Xu J.,Shanghai Aircraft Customer Service Co. | Bi C.-X.,Beihang University
19th International Conference on Industrial Engineering and Engineering Management: Assistive Technology of Industrial Engineering | Year: 2013

Customer service ability is one of the key competitiveness in market competition for civil aircraft manufacturers who participate. To establish the mature reliable civil aircraft customer service system based on the service strategy is an important aspect to reflect the customer service skills. Based on the idea of system dynamics, this paper constructed a system dynamics model (SD model) of the customer service system of COMAC, and through the simulation of the system, analyzed the key factors which affect the running of the customer service system, to provide the basis for decision-making and measures. © 2013 Springer-Verlag Berlin Heidelberg.


Yan Q.,Shanghai Aircraft Customer Service Co. | Xiong J.-J.,Beihang University | Qiu T.,Shenyang Aircraft Design Institute
Beijing Keji Daxue Xuebao/Journal of University of Science and Technology Beijing | Year: 2011

The concept of safety factor with two-indexes of reliability and confidence levels was presented by introducing the confidence level index. Based on the reliability theory, new formulae of safety factor with two-indexes of reliability and confidence levels were derived to take the sample size of experimental data into account and to determine the safety factor value from small sample test data for structural reliability design. The new safety factor was applied to two sets of experimental results, demonstrating the practical and convenient use of the proposed technique. It is shown from these examples that the safe factor can be obtained realistically according to small sample test data using the new formulae.


Qin Y.,Beihang University | Qin Y.,Shanghai Aircraft Customer Service Co. | Gao Y.-T.,Beihang University | Shen Y.-J.,Beihang University | And 3 more authors.
Physica Scripta | Year: 2013

In fluids, Korteweg-de Vries-type equations are used to describe certain nonlinear phenomena. Studied in this paper is a variable-coefficient (2 + 1)-dimensional generalized breaking soliton equation, which models the interactions of Riemann waves with long waves. By virtue of the Bell-polynomial approach, bilinear forms of such an equation are obtained. N-soliton solutions are constructed in terms of the exponential functions and Wronskian determinant, respectively. Solitonic propagation and interaction are discussed with the following conclusions: (i) the appearance of characteristic lines such as the periodic and parabolic shapes depends on the form of the variable coefficients; and (ii) interactions of two solitons and three solitons are shown to be elastic. © 2013 The Royal Swedish Academy of Sciences.


Chuan Z.,Nanjing University of Aeronautics and Astronautics | Chuan Z.,Shanghai Aircraft Customer Service Co. | Chen Y.,Shanghai Maritime University | Yao W.,Nanjing University of Aeronautics and Astronautics
International Journal of Fatigue | Year: 2014

The method of using fractal dimension of corroded surface to predict residual lives of pre-corroded specimens is illustrated in this paper. A new technique to calculate 3D fractal dimension was proposed. The relationship between residual lives of pre-corroded smooth and notch specimens and 3D fractal dimensions of corroded surfaces were discussed. The new methods based on 3D fractal dimension of corroded surface to calculate pre-corroded residual lives of smooth and notch specimens and their probability distribution were proposed. The results indicated that 3D fractal dimensions of corroded surfaces can be used to calculate residual life of pre-corroded specimens and their probability distribution accurately. © 2013 Elsevier Ltd. All rights reserved.


Liu Z.-H.,Nanjing University of Science and Technology | Liu Z.-H.,Shanghai Aircraft Customer Service Company Ltd | Yin X.-C.,Nanjing University of Science and Technology
Gongcheng Lixue/Engineering Mechanics | Year: 2010

The impact problem of a simply supported beam with variable cross-section struck horizontally by a round-nosed rigid mass is investigated by considering the local deformation behavior of multiple elastic-plastic contacts induced by multiple impacts and multiple separations. A local elastic-plastic contact deformation model is applied and extended for multiple elastic-plastic impact problems. The finite difference method is used to solve dynamic equations. The numerical simulations show that such a horizontal strike is indeed a complicated process of multiple elastic-plastic impacts. There are usually more than two impact zones in which each of them consists of complicated multiple sub-impacts. It is found that the other impact zones might occupy a considerable impact impulse totally comparing to the first impact zone. Hence, the other impact zones have a significant influence on the dynamic response of the beam. It is found as well that the other impacts might make the mass loss considerable kinetic energy totally comparing to the first impact. It implies that the multiple impacts are of an important role upon the impact physical behavior of the beam. In addition, the numerical results show that the variations of the beam's cross-section will make the impact zones contract or stretch and make the second impact zone take place late or early.


Yang J.,Nanjing University of Science and Technology | Yin X.,Nanjing University of Science and Technology | Liu Z.,Shanghai Aircraft Customer Service Company Ltd | Qian P.,Nanjing University of Science and Technology
Jixie Gongcheng Xuebao/Journal of Mechanical Engineering | Year: 2012

By employing the overstress model, the effect of strain rate on local elastic viscoplastic contact deformation and free-free beam dynamics is considered. A local elastic viscoplastic uniaxial compression deformation model is presented to take into account the multiple impact-contact deformations. By the use of the finite difference method and the impact and separation conditions, the sub-impact phenomenon of a free-free beam horizontally stuck by a rigid mass is investigated. It is found that the horizontal impact is indeed a complicated process including elastic viscoplastic sub-impacts. The effect of strain rate of the beam has a significant role in local contact deformation and beam dynamics. It results in the obvious variations of impact force, elastic deformation and viscoplastic deformation of the beam. The present numerical simulations are compared with those solved by the three-dimensional dynamic finite element method. The comparisons illustrate that the present method is reasonable. ©2012 Journal of Mechanical Engineering.


Chen X.,RMIT University | Ren H.,RMIT University | Ren H.,Shanghai Aircraft Customer Service Co. | Bil C.,RMIT University | Cai J.,Nanjing University of Aeronautics and Astronautics
Journal of Aircraft | Year: 2014

During operational service, composite structures in aircraft are inspected at predetermined intervals. If damage is detected, engineers refer to the structural repair manual to determine appropriate repair procedures, which ensures safety. But there is little information on that whether the existed repair policy is the most cost effective. In this paper, a concept called repair tolerance is proposed by defining two critical thresholds, when to repair and when to replace, to address both safety and economic issues. A simulation procedure was developed to model the operational lifecycle of the structural strength considering impact damage. A probabilistic approach was applied to optimize the two thresholds in repair tolerance by assessing the probability of failure as well as minimizing the total maintenance cost. This method can be used by aircraft manufacturers and operators to support their decision-making for an optimized repair policy. Copyright © 2013 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.


Chen X.,RMIT University | Ren H.,RMIT University | Liu J.,Shanghai Aircraft Customer Service Company
Journal of Aircraft | Year: 2013

The existing structural rating system in the maintenance steering group-3 is facing difficulties with developing new aircraft. There is always a lack of available data to help make proper inspection intervals. By taking advantage of the powerful learning ability and data fusion capability of the backpropagation network, this paper aims to develop a new decision support system for the determination of scheduled maintenance inspection intervals for aircraft structures susceptible to accidental damage. As long as various data are available, regardless of engineering experience, experimental values, and in-service reliability data feedback, the backpropagation network has been proven able to make acceptable predictions after training, making accidental damage rating a dynamic and flexible procedure. © 2012 by Ernesto Benini.


Wang W.,Northwestern University | Dai Y.,Shanghai Aircraft Customer Service Co. | Zhang C.,Northwestern University | Gao X.,University of Akron | Zhao M.,Northwestern University
Materials | Year: 2016

Modeling the random fiber distribution of a fiber-reinforced composite is of great importance for studying the progressive failure behavior of the material on the micro scale. In this paper, we develop a new algorithm for generating random representative volume elements (RVEs) with statistical equivalent fiber distribution against the actual material microstructure. The realistic statistical data is utilized as inputs of the new method, which is archived through implementation of the probability equations. Extensive statistical analysis is conducted to examine the capability of the proposed method and to compare it with existing methods. It is found that the proposed method presents a good match with experimental results in all aspects including the nearest neighbor distance, nearest neighbor orientation, Ripley"s K function, and the radial distribution function. Finite element analysis is presented to predict the effective elastic properties of a carbon/epoxy composite, to validate the generated random representative volume elements, and to provide insights of the effect of fiber distribution on the elastic properties. The present algorithm is shown to be highly accurate and can be used to generate statistically equivalent RVEs for not only fiber-reinforced composites but also other materials such as foam materials and particle-reinforced composites. © 2016 by the authors; licensee MDPI, Basel, Switzerland.

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