Shakedown analysis of a wind turbine gear considering strain-hardening and the initial residual stress

Haifeng He,Hua iju Liu,Caichao Zhu,Longhua Yuan 대한기계학회 2018 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.32 No.11

Under some heavy-duty conditions, the shakedown state may occur on gears such as those used in a megawatt wind turbine gearbox. The plastic deformation and the residual stress formed within the shakedown process further influence the contact behavior and the service life of the gear. The initial residual stress caused by the heat treatment of the case-hardening gear, together with the strain-hardening constitutive behavior of the material, have a combined effect on the shakedown state. A two-dimensional elastic-plastic contact numerical model was developed for a case-hardened wind turbine gear to study effects of the initial residual stress and the strain-hardening properties. Plastic strain and residual stress are calculated at each loading cycle without the consideration of the tooth friction. The initial yield limit and the hardening modulus of the material were obtained through a tension test on a universal tensile test machine. The initial residual stress distribution was measured with the X ray diffraction method and then embedded in the finite element model. The results show that strain-hardening behavior can significantly improve the shakedown performance, and the larger the hardening modulus is, the less the maximum plastic strain is at the final shakedown state. Initial residual compressive stress is helpful to improve the shakedown performance, while initial residual tensile stress has negative influence on the shakedown performance. As the normal load increases, the influence of the initial residual stress on the shakedown state becomes weakened.

Antiserum Preparation of Recombinant Sweet Potato Latent Virus-Lotus (SPLV-Lotus) Coat Protein and Application for Virus-Infected Lotus Plant Detection

Zhen He,Tingting Dong,Wen Chen,Tielin Wang,Haifeng Gan,LiangJun Li 한국식물병리학회 2020 Plant Pathology Journal Vol.36 No.6

Lotus is one of the most important aquatic vegetables in China. Previously, we detected sweet potato latent virus from lotus (SPLV-lotus) and found that it has highly significant sequence diversity with SPLV-sweet potato isolates (SPLV-sp). Here, we developed serological methods for the detection of SPLV-lotus in Chinese lotus cultivation areas. Based on the high sensitivity of SPLV-lotus coat protein antiserum, rapid, sensitive and large-scale diagnosis methods of enzyme-linked immunosorbent assay (ELISA) and dot blot in lotus planting area were developed. The established ELISA and dot blot diagnostic methods can be used to detect SPLVlotus from samples successfully. And our results also showed that the SPLV-lotus and sweet potato isolates appeared clearly distinction in serology. Our study provides a high-throughput, sensitive, and rapid diagnostic method based on serology that can detect SPLV on lotus, which is suggested to be included in viral disease management approach due to its good detection level.

Object-oriented Knowledge Modelling for Conceptual Design of Mechanisms

Bin He,Zhongqiang Deng,Haifeng Lv 보안공학연구지원센터 2013 International Journal of Database Theory and Appli Vol.6 No.5

Convenient and Robust Route to Photoswitchable Hierarchical Liquid Crystal Polymer Stripes via Flow-Enabled Self-Assembly

Li, Xiao,Li, Bo,He, Ming,Wang, Wei,Wang, Tianjie,Wang, Aurelia,Yu, Jiwoo,Wang, Zhonglin,Hong, Suck Won,Byun, Myunghwan,Lin, Shaoliang,Yu, Haifeng,Lin, Zhiqun American Chemical Society 2018 ACS APPLIED MATERIALS & INTERFACES Vol.10 No.5

<P>Hierarchically arranged stripes of photoswitchable liquid crystal polymers (LCPs) containing azobenzene moieties were conveniently crafted via a flow-enabled self-assembly (FESA). Interestingly, by subjecting a drop of LCP solution to dry in a restricted geometry comprising two nearly parallel plates with a stationary upper plate and a movable lower plate that programmably traveled in a 'stop -and-move' manner during the FESA process, photoswitchable LCP stripes were yielded, displaying two modes of deposition, namely, periodic primary stripes of large dimensions and regularly spaced secondary stripes of small dimensions situated between adjacent, primary stripes (i.e., forming hierarchical LCP stripes). Notably, these hierarchical azobenzene moieties-containing stripes demonstrated sequential photoinduced reversible phase transition (i.e., photoswitching) due to the thickness difference between primary and secondary stripes. A UV light-induced expansion effect. was observed on the LCP stripes. Clearly, such rapid creation of hierarchical stripes by FESA represents a robust means of organizing polymers, nanoparticles, colloids, DNA, etc. into complex yet ordered patterns over a large area in a simple and controllable manner for potential use in surface relief grating, photoactuators, photoswitchable devices, antifake labels, etc.</P>

CuO-doped Ce for catalytic wet peroxide oxidation degradation of quinoline wastewater under wide pH conditions

Zhaojie Jiao,Xianming Zhang,Haifeng Gong,Donglin He,Hong Yin,Yunqi Liu,Xu Gao 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.105 No.-

This study aimed to treat toxic and refractory organic wastewater, and to address the limitations ofFenton method in treating organic wastewater, that the active components are easy to lose and usuallyoperate at the pH value of 2 3. In the present study, CuCe oxide catalyst was produced through citricacid-assisted complexation. Besides, the structural stability and catalytic wet peroxide oxidation (CWPO)performance of the catalyst after 5 times of application were delved into by characterization. The effectsof catalyst dosage and pH on quinoline removal were ascertained, while the reusability of the catalystwas explored. Moreover, the variations of pH, hydroxyl radical concentration and UV–Vis spectra inthe reaction system were analyzed. The possible degradation pathway and the catalytic mechanism werealso discussed. As suggested from the results, the catalyst exhibited high catalytic activity, structural stabilityand pH adaptability; it also had high CWPO performance for quinoline at the pH from 3.8 to 10.5,and the pH value need not be regulated. Under optimal conditions, 98.1% of quinoline and 86.1% of totalorganic carbon (TOC) were removed. In the CWPO process of quinoline, the OH attacked the nitrogen ringand the benzene ring in sequence.

Dibenzothiophene hydrodesulfurization over MoP/SiO2 catalyst prepared with sol-gel method

Shuwen Gong,Lijun Liu,Haifeng He,Qingxin Cui 한국화학공학회 2010 Korean Journal of Chemical Engineering Vol.27 No.5

Silica-supported molybdenum phosphide, MoP/SiO2 catalysts with different Mo weight loadings were prepared by temperature programmed reduction of the oxidic catalyst precursors, which were prepared via sol-gel technique using ethyl silicate-40 as silica source. Samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), BET surface area measurements, and their catalytic activity in hydrodesulfurization (HDS)was tested with dibenzothiophene (DBT) as model compound. XRD analysis revealed the amorphous nature of the catalyst up to 10 wt% Mo loading and the formation of crystalline MoP phase on amorphous silica support with higher Mo loading. BET surface area showed high surface area for catalysts prepared by sol-gel technique with lower Mo content, and the surface area decreased with increasing in Mo loading. The HDS results showed that prepared MoP/SiO2 exhibited high HDS activity and stability toward the catalytic test. Among the series of catalysts prepared, MoP/SiO2 containing 20 wt% Mo was found to be the most active catalyst. And the effects of reaction temperature and hydrogen pressure on conversion and product selectivity were investigated.

Behaviors of box-shape steel reinforced concrete composite beam

Chun Yang,Jian Cai,Yi Wu,Jiangang He,Haifeng Chen 국제구조공학회 2006 Structural Engineering and Mechanics, An Int'l Jou Vol.22 No.4

Behaviors of box-shape steel reinforced concrete composite beam

Yang, Chun,Cai, Jian,Wu, Yi,He, Jiangang,Chen, Haifeng Techno-Press 2006 Structural Engineering and Mechanics, An Int'l Jou Vol.22 No.4

Experimental studies on the behaviors of box-shape steel reinforced concrete (SRC) composite beams were conducted. Seven 1:3 scale model composite beams were tested to failure. Each of the beams was simply supported at the ends and two concentrated loads were applied at the one-third span and two-thirds span respectively. Experimental results indicate that the flexural strength can be enhanced when the ratio of flexural reinforcements and flange thickness of the shape steel are increased; the shear strength is enhanced with increase of web thickness of the shape steel. Insignificant effects of concrete in the box-shape steel are found on improving the flexural strength and shear strength of the box-shape SRC composite beams, thus concrete inside the box-shape steel can be saved, and the weight of the SRC beams can be decreased. Shear studs can strengthen the connection and co-work effects between the shape steel and the concrete and enhance the shear strength, but stud design for the composite beams should be further improved. Formulas for flexural and shear strength of the composite beams are proposed, and the calculated results are in good agreement with the experimental results. In general, the box-shape SRC composite beam is a kind of ductile member, and suitable for extensive engineering application.

Integral Attacks on Some Lightweight Block Ciphers

( Shiqiang Zhu ),( Gaoli Wang ),( Yu He ),( Haifeng Qian ) 한국인터넷정보학회 2020 KSII Transactions on Internet and Information Syst Vol.14 No.11

At EUROCRYPT 2015, Todo proposed a new technique named division property, and it is a powerful technique to find integral distinguishers. The original division property is also named word-based division property. Later, Todo and Morii once again proposed a new technique named the bit-based division property at FSE 2016 and find more rounds integral distinguisher for SIMON-32. There are two basic approaches currently being adopted in researches under the bit-based division property. One is conventional bit-based division property (CBDP), the other is bit-based division property using three-subset (BDPT). Particularly, BDPT is more powerful than CBDP. In this paper, we use Boolean Satisfiability Problem (SAT)-aided cryptanalysis to search integral distinguishers. We conduct experiments on SIMON-32/-48/-64/-96, SIMON (102)-32/-48/-64, SIMECK-32/-48/-64, LBlock, GIFT and Khudra to prove the efficiency of our method. For SIMON (102)-32/-48/-64, we can determine some bits are odd, while these bits can only be determined as constant in the previous result. For GIFT, more balanced (zero-sum) bits can be found. For LBlock, we can find some other new integral distinguishers. For Khudra, we obtain two 9-round integral distinguishers. For other ciphers, we can find the same integral distinguishers as before.

Fatigue behavior of hybrid GFRP-concrete bridge decks under sagging moment

Haohui Xin,Yuqing Liu,Jun He,Haifeng Fan,Youyou Zhang 국제구조공학회 2015 Steel and Composite Structures, An International J Vol.18 No.4

This paper presents a new cost-effective hybrid GFRP-Concrete deck system that the GFRP panel serves as both tensile reinforcement and stay-in-place form. In order to understand the fatigue behavior of such hybrid deck, fatigue test on a full-scale specimen under sagging moment was conducted, and a series of static tests were also carried out after certain repeated loading cycles. The fatigue test results indicated that such hybrid deck has a good fatigue performance even after 3.1 million repeated loading cycles. A three-dimensional finite element model of the hybrid deck was established based on experimental work. The results from finite element analyses are in good agreement with those from the tests. In addition, flexural fatigue analysis considering the reduction in flexural stiffness and modulus under cyclic loading was carried out. The predicted flexural strength agreed well with the analytical strength from finite element simulation, and the calculated fatigue failure cycle was consistent with the result based on related S-N curve and finite element analyses. However, the flexural fatigue analytical results tended to be conservative compared to the tested results in safety side. The presented overall investigation may provide reference for the design and construction of such hybrid deck system.