Layout Optimization for Blended Wing Body Aircraft Structure

Wensheng Zhu,Xiongqing Yu,Yu Wang 한국항공우주학회 2019 International Journal of Aeronautical and Space Sc Vol.20 No.4

Structural layout design of blended wing body (BWB) aircraft in the preliminary design phase is a challenging optimization problem due to large numbers of design variables and various constraints. A two-loop optimization strategy is proposed to solve the BWB aircraft structural layout design problem considering constraints of the displacement, stress, strain, and buckling. The two-loop optimization consists of an inner loop and an outer loop. The inner loop is to optimize each stiffened panel of the BWB aircraft structure, and outer loop is to find the best layout design. To improve computational efficiency, an equivalent finite element model is applied to BWB aircraft structure analysis, and an analytical method is used for buckling and static analysis of the stiffened panels. The proposed method can efficiently solve the structural layout optimization problem of a notional BWB aircraft with acceptable computational burden. The result indicates the mass of main load-carrying structure of the BWB aircraft is reduced by 9.28% compared to that of the initial structural layout.

A Hybrid CBPWM Scheme for Single-Phase Three-Level Converters

Wang, Shunliang,Song, Wensheng,Feng, Xiaoyun,Ding, Rongjun The Korean Institute of Power Electronics 2016 JOURNAL OF POWER ELECTRONICS Vol.16 No.2

A novel hybrid carrier-based pulse width modulation (CBPWM) scheme that combines unipolar and dipolar modulations is proposed for single-phase three-level rectifiers, which are widely applied in railway traction drive systems. The proposed CBPWM method can satisfy the volt-second balancing principle in the complete modulation index region through overmodulation compensation. The modulation scheme features two modulation modes: unipolar and dipolar. The operation range limits of these modulation modes can be modified by changing the separation coefficient. In comparison with the traditional unipolar CBPWM, the proposed hybrid CBPWM scheme can provide advantageous features, such as lower high-order harmonic distortion of the line current and better utilization of switching frequency. The separation coefficient value is optimized to achieve the maximum utilization of these advantages. The experimental results verify the feasibility and effectiveness of the proposed hybrid CBPWM scheme.

Research on facility layout optimization algorithm of deep-water semi-submersible drilling platform

Hongyan Wang,Wensheng Xiao,Lei Wu,Keke Wei,Congcong Xu,Chao Hou,Junguo Cui,Jie Li 대한기계학회 2019 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.33 No.2

We aimed to create a facility layout design of semi-submersible drilling platform (DSDP) with performance constraints. The Boltzmann survival mechanism of simulated annealing algorithm was introduced into the replacement strategy of genetic algorithm to form an improved genetic algorithm called genetic and simulated annealing algorithm (GASA). The new algorithm alleviates the “combination explosion” and premature convergence of the traditional genetic algorithm. The layout problem of DSDP is efficiently solved by using this new algorithm. When the number of layout objects increases, GASA’s performance is better than that of the genetic algorithm.

Growth of Ag3Sn and Sn Nanoparticles Based on the Variation of Reaction Conditions

Yao Wang,Wensheng Liu,Yunzhu Ma,Siwei Tang,Yufeng Huang 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2018 NANO Vol.13 No.7

Tin and tin-based nanoalloys especially Sn-3.5Ag (wt.%) eutectic alloys have been prepared by numerous methods as the promising alternative solder in electronic packaging application. However, issues of agglomeration and oxidation emerged owing to shrinking size of nanoparticles. In this study, the Sn/Ag3Sn nanoparticles as small as 10 nm have been synthesized successfully through chemical reduction method. Concentration of precursor and reducing agent have been studied so as to control the reaction rate, thus achieving the optimized conditions avoiding agglomeration. A centralized size distribution has been achieved by separating nucleation and growth periods. It has been revealed that the obtained nanoparticles are composed of β-Sn and Ag3Sn which represent a successful co-reduction. β-Sn and Ag3Sn NPs have various average size for their distinct critical nucleation radius and disparate mole ratio of Sn and Ag. The β-Sn surface has almost 4-nm thick amorphous tin oxide layer but Ag3Sn surface has not, because the lattice distortion caused by the replacement of silver by tin hinders the diffusion of oxygen, improving oxidation resistance and dispersing performance.

A Hybrid CBPWM Scheme for Single-Phase Three-Level Converters

Shunliang Wang,Wensheng Song,Xiaoyun Feng,Rongjun Ding 전력전자학회 2016 JOURNAL OF POWER ELECTRONICS Vol.16 No.2

A novel hybrid carrier-based pulse width modulation (CBPWM) scheme that combines unipolar and dipolar modulations is proposed for single-phase three-level rectifiers, which are widely applied in railway traction drive systems. The proposed CBPWM method can satisfy the volt-second balancing principle in the complete modulation index region through overmodulation compensation. The modulation scheme features two modulation modes: unipolar and dipolar. The operation range limits of these modulation modes can be modified by changing the separation coefficient. In comparison with the traditional unipolar CBPWM, the proposed hybrid CBPWM scheme can provide advantageous features, such as lower high-order harmonic distortion of the line current and better utilization of switching frequency. The separation coefficient value is optimized to achieve the maximum utilization of these advantages. The experimental results verify the feasibility and effectiveness of the proposed hybrid CBPWM scheme.

Pricing options with credit risk in a reduced form model

Xiaonan Su,Wensheng Wang 한국통계학회 2012 Journal of the Korean Statistical Society Vol.41 No.4

This article investigates the valuation of European option with credit risk in a reduced form model. We assume that the interest rate follows the Vasicek model and the intensity of default is driven by a jump diffusion process. We obtain the closed form formula for the price of the option and provide some numerical illustrations of the results obtained.

Pricing options with credit risk in a reduced form model

Su, Xiaonan,Wang, Wensheng 한국통계학회 2012 Journal of the Korean Statistical Society Vol.41 No.4

This article investigates the valuation of European option with credit risk in a reduced form model. We assume that the interest rate follows the Vasicek model and the intensity of default is driven by a jump diffusion process. We obtain the closed form formula for the price of the option and provide some numerical illustrations of the results obtained.

Effect of temperature and spring-mass systems on modal properties of Timoshenko concrete beam

Liu, Hanbing,Wang, Hua,Tan, Guojin,Wang, Wensheng,Liu, Ziyu Techno-Press 2018 Structural Engineering and Mechanics, An Int'l Jou Vol.65 No.4

An exact solution for the title problem was obtained in closed-form fashion considering general boundary conditions. The expressions of moment, shear and shear coefficient (or shear factor) of cross section under the effect of arbitrary temperature distribution were first derived. In view of these relationships, the differential equations of Timoshenko beam under the effect of temperature were obtained and solved. Second, the characteristic equations of Timoshenko beam carrying several spring-mass systems under the effect of temperature were derived based on the continuity and force equilibrium conditions at attaching points. Then, the correctness of proposed method was demonstrated by a Timoshenko laboratory beam and several finite element models. Finally, the influence law of different temperature distribution modes and parameters of spring-mass system on the modal characteristics of Timoshenko beam had been studied, respectively.

Electrospun Li2MnO3-Modified Li1.2NixCo0.1Mn0.9-xO2 Nanofibers: Synthesis and Enhanced Electrochemical Performance for Lithium-Ion Batteries

Jing Yao,Xinlu Wang,Xinru Zhao,Jinxian Wang,Hongbo Zhang,Wensheng Yu,Guixia Liu,Xiangting Dong 대한금속·재료학회 2016 ELECTRONIC MATERIALS LETTERS Vol.12 No.6

The Li2MnO3-modified Li1.2NixCo0.1Mn0.9-xO2 (x = 0.2, 0.45, 0.7)as cathode materials for lithium-ion batteries have beensuccessfully synthesized by a simple electrospinning process. Thestructure, morphology and electrochemical performances of theresulting products are studied systematically. The as-preparedLi2MnO3-modified Li1.2NixCo0.1Mn0.9-xO2 (x = 0.2, 0.45, 0.7) with adiameter of 200-300 nm has an initial discharge capacity of168.740 mAh·g−1, coulombic efficiency of 99.6% and a reversiblecapacity as high as 139.016 mAh·g−1 after 200 cycles at a currentrate of 0.2 C. The excellent electrochemical performances ofwhich are attributed to the stabilization of Li2MnO3 structure, therole of Li2MnO3 is contribute extra lithium to the reversiblecapacity and to facilitate Li+ transport through the structure.

In situ synthesis of “brick and mortar”-type lignin-derived carbon/TiO2 composite with a remarkable photocatalytic performance

Binpeng Zhang,Dongjie Yang,Wensheng Lin,Huan Wang,Yong Qian,Xueqing Qiu 한국공업화학회 2021 Journal of Industrial and Engineering Chemistry Vol.97 No.-

Alkali lignin (AL), an industrial waste from pulping black liquor, is mainly applied as a low-gradecombustible energy source. Design and preparation of high value-added materials with AL is still achallenge. In this work, wefirstly introduced ammonium group into AL and prepared quaternized alkalilignin (QAL) for improving the solubility in acidic aqueous solution. Then a facile sol–gel andcarbonization process was developed to fabricate lignin-derived carbon/TiO2 (LC/TiO2) compositephotocatalyst using QAL as the carbon precursor. The microstructural characteristics and optical propertyof the LC/TiO2 composite were systematically characterized. Composite exhibited a “brick (TiO2nanoparticles) and mortar (LC)”-type construction, and TiO2 nanoparticles were coated with LC. Theintroduction of LC endowed TiO2 with extended photoabsorption region and enhanced separation ofphoto-generated charge carriers. LC/TiO2 obtained at a carbonization temperature of 650 C presentedthe highest photocatalytic activity for the degradation of organic dye, which was about 3.4 times that ofbare TiO2. Moreover, LC/TiO2 also presented good recyclability. This facile strategy not only offers greatopportunities for the high value-added application of industrial lignin, but also promotes the practicalapplication of TiO2 photocatalyst.