Value range optimization of ply parameter for composite wind turbine blades based on sensitivity analysis

Pengwen Sun,Yin Zhang,Lanting Zhang,Weifei Hu 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.3

Blade ply parameters are important design factors that influence the performances of wind turbine blades. This paper proposes a sensitivity analysis method of the blade ply parameters that fuses the relative sensitivity analysis of multi-parameters and the interval sensitivity analysis of single-parameters. A method for identifying the stability region of the sensitive parameters is presented. Coupled mathematical models of the blade static strength and the blade stiffness as a function of the blade ply parameters are established by incorporating experimental design, finite element analysis, and multiple nonlinear regression. The moment independent sensitivity analysis method based on the cumulative distribution function is used to analyze the multi-parameter relative sensitivity, and the direct derivative method was used to analyze single-parameter interval sensitivity. The sensitive and insensitive ply parameters are identified, and the initial stability and instability regions of the ply parameters are determined. A case study of a 1.5 MW blade shows that the ply angle and the ply thickness are sensitive parameters, and the ply stacking sequence is an insensitive parameter. The optimal and stability value ranges of the ply angle and the ±x° ply thickness ratio are [44°, 45°] and [44 %, 48 %], respectively. Hence, the validity and reliability of the proposed method is verified.

Magnetic and optical properties of Gd-Tl substituted M-type barium hexaferrites synthesized by co-precipitation technique

Ghulam Abbas Ashraf,Lanting Zhang,Waseem Abbas,Ghulam Murtaza 한국물리학회 2019 Current Applied Physics Vol.19 No.4

The substitution of numerous cations into hexagonal ferrite has been extensively used to endow novel properties and functionalities for various applications. In the present work Gd-Tl substituted barium hexaferrites prepared by co-precipitation process, having the composition Ba0.75Cu0.25(GdxTl0.5-x)Fe11.5O19 (x=0.0, 0.25 and 0.50). The hexaferrite formation during calcination of sample x=0.25 was confirmed by TGA/DSC which was processed at 1000 °C for 3 h. The analysis of X-ray diffraction depicts the existence of magneto-plumbite structure with the formation of a minor secondary α–Fe2O3 phase x≤0.0 and BaFe2O4 phase x≤0.50. UV–Vis spectra reveal the dropping down behavior in the optical energy band gap from 2.47 eV to 1.74 eV. The grains with hexagonal platelet-like shape having size of 0.415–0.446 μm of magnetic powder nanoparticles (MPs) are observed by SEM images. The energy dispersive spectrometer (EDS) analysis was employed for presence of ferrite elements within a single particle. Hysteresis loops signifies the magnetization (Ms) and remnant magnetization (Mr) first increases up to x=0.25 then reduces with the substitution (x) increment; contrarily, the coercivity (Hc) exhibited initially decreased with maximum content of Tl at x=0.0 then increases at x=0.25 after that it decreases at x=0.50. Maximum values such as Ms (51.727 emu/g), Mr (28.061 emu/g), and Hc (4.057 kOe) are attained for x=0.25 at room temperature. The synthesized magnetic nanoparticles are found to be suitable for microwave absorbing materials, permanent magnets, catalyst, high density recording media and optoelectronic devices.

Factors Associated with Macular Staphyloma Area on Ultra-widefield Fundus Images

Xinmei Zhang,Emmanuel Eric Pazo,Aoqi Zhang,Lanting Yang,Guangzheng Dai,Xianwei Wu,Yang Xia,Amit Meshi,Wei He,Tiezhu Lin 대한안과학회 2022 Korean Journal of Ophthalmology Vol.36 No.3

Effect of δ-Ferrite Evolution and High-Temperature Annealing on Mechanical Properties of 11Cr3W3Co Ferritic/Martensitic Steel

Zhongxia Shang,Yinzhong Shen,Bo Ji,Lanting Zhang 대한금속·재료학회 2016 METALS AND MATERIALS International Vol.22 No.2

An 11Cr3W3Co ferritic/martensitic steel was annealed at 1100 °C for different time to gradually dissolve δ-ferrite, and then conducted tensile, hardness, and short-term creep tests in combination with microstructural characterization to study the effect of δ-ferrite on the mechanical properties of high-Cr ferritic/martensitic steels. The amount of δ-ferrite gradually decreased to a minimum value with increasing annealing time up to 10 h, and then tended to an ascending tendency when annealed for 15 and 20 h. Accordingly the tensile strength at 300 and 650 °C, and Vickers hardness of the steel had an increase and a decrease tendency when δ-ferrite amount decreased down to its minimum value and increased again, respectively. The short-term creep property at 210 MPa at 650 °C of the steel exhibited a serious degradation as annealing time gradually increased to 15 h. The morphology and orientation of δ-ferrite grains seriously affected the short-term creep property of the steel. δ-ferrite with a continuously bamboo-like shape parallel to loading direction effectively improved the short-term creep property of the steel at high temperature, while δ-ferrite with a granular or block shape seriously damaged the short-term creep property of the steel. These findings have also been discussed.

중국 농민전문합작사 발전 역사의 소고

김용훈 ( Longxun Jin ),장뢰 ( Lei Zhang ),조란정 ( Lanting Zhao ),김성철 ( Chengzhe Jin ) 농협대학교 협동조합경영연구소 2014 협동조합경영연구 Vol.41 No.-

본 논문은 문헌자료를 활용하여 중국 농민전문합작사의 발전에 대해 계통 적으로 분석하였다. 중국 농민전문합작사의 발전은 인위적인 추동으로부터 점차적으로 자발형성의 발전을 이루었으며, 또한 정부의 지도 지원과정을 통해 이루어 졌다. 본문은 1915년 서구 사상과 이론이 유입된 때로부터 1920년대 연수(晏殊)등이 거행한 농촌운동, 건국 전 국공양당합작사업의 발전 및 건국 후 합작화운동의 굴곡있는 전체적인 전개과정에 대해 논술하였다. 농민전문합작사의 역사적 의미는 개혁개방 이래 농촌발전과 시장경제 진행 속에서 농민들의 시장 거래 지위 변화를 촉진하고 중국 경제의 지속적인 발전에 기여하는 등 중국의 신농촌건설에 큰 역할을 하였다는 것이다. This paper uses Law of literature, systematically analyzes the development of farmer``s professional cooperative. The development of farmer``s professional joint-venture company in China has experienced from artificial drive toward spontaneous and the process of government leading, independent development. This article expounds the introduction of western thought in 1915, rural campaign held in 20``s, the Nationalist Party and the Communist Party``s cooperation before establishing the People``s Republic of China as well as the tortuous road of cooperative movement after establishing the People``s Republic of China. The true sense of the farmer``s professional cooperative is in the process of rural development of market economy since the reform and opening up, the farmers in order to change market trading status, had promoted the sustainable economic development in our country.

A discrete material optimization method with a patch strategy based on stiffness matrix interpolation

Pengwen Sun,Jie Zhang,Penghui Wu,Jiandong Li,Lanting Zhang,Weifei Hu 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.2

A discrete material optimization method with a patch strategy based on the stiffness matrix interpolation is proposed, and a comprehensive technical process of patch discrete material optimization using existing finite element software was developed. This method employs the stiffness matrix instead of the constitutive matrix for material interpolation, which facilitates the optimization process integrated with the existing finite element software. The element stiffness matrix can be derived directly from the finite element analysis, which can not only ensure the correctness of the data, but also reduce the programming work of solving the numerical integration of the composite constitutive matrix. The mathematical model of the patch discrete material optimization is established, which takes the artificial density as the design variable, the minimum compliance as the objective function, and the sequential quadratic programming (SQP) algorithm as the optimization solver. Numerical examples show that by seeking a balance between the number of regions and practical production, the performance of the composite could be further improved using the discrete material optimization method with a patch strategy. Besides, the convergence rate of the optimization is increased by introducing the sum constraints of the design variables and the value functions. The effectiveness and the feasibility of the method were verified.

Direct Fermentation of Potato Starch in Wastewater to Lactic Acid by Rhizopus oryzae

Li Ping Huang,Bo Jin,Xianliang Qiao,Jingwen Chen,Paul Lant,Wence Sun 한국생물공학회 2004 Biotechnology and Bioprocess Engineering Vol.9 No.4

The fungal species of Rhizopus oryzae 2062 has the capacity to carry out a single stage fermentation process for lactic acid production from potato starch wastewater. Starch hydrolysis, reducing sugar accumulation, biomass formation, and lactic acid production were affected with variations in pH, temperature, and starch source and concentration. A growth condition with starch concentration approximately 20 g/L at pH 6.0 and 30oC was favourable for starch fermentation, resulting in a lactic acid yield of 78.3%85.5% associated with 1.52.0 g/L fungal biomass produced in 36 h of fermentation.

Study on Spheroidizing Technology of Spherical Cast Tungsten Carbide

Li Yuxi,Zhou Yonggui,Li Weiqin,Pan Deng,Zhang Lanting 한국분말야금학회 2006 한국분말야금학회 학술대회논문집 Vol.2006 No.1

This paper introduces a special spheroidizing technology at ultra-high temperature. The conventional cast tungsten carbide (YZ) is melted at high temperature, rapidly cooled and spheroidized on a new ultra-high temperature spheroidizing equipment to prepare various grades WSC powders.