Topology optimization of unsymmetrical complex plate and shell structures bearing multicondition overload

Yangyang Zhang,Yixiao Qin,Jinpeng Gu,Qianqian Jiao,Feng Wang,Zhenshan Guo,Hao Zhang,Jianjun Wang,Chenghong Mi,Huaipeng Zheng 대한기계학회 2021 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.35 No.8

Unsymmetrical complex plate and shell structure is one of the common engineering structures. In practice, more redundant materials exist because of the irrationality of this kind of structure with heavy load and multiple working conditions, and the study of its topology optimization has become an engaging topic. Using the SIMP model, topological results show that one side of the main web is a hollow structure, and the other side of the auxiliary web is a truss structure. According to the topological results and considering manufacturable processing, a new structure is redesigned, the size and shape of the redesigned structure is secondary optimized, and the final structure is obtained. The method in this paper not only meets the performance requirements of the unsymmetrical complex plate and shell structures, but also realizes the topology and lightweight. The effectiveness scientific research value of the proposed method is verified by engineering examples.

Layout Optimization of Stiffeners in Heavy-Duty Thin-Plate Box Grider

Hao Zhang,Yixiao Qin,Jinpeng Gu,Haibiao Gao,Qianqian Jiao,Feng Wang,Zhenshan Guo,Yangyang Zhang,Chenghong Mi 대한토목학회 2021 KSCE Journal of Civil Engineering Vol.25 No.8

The optimization of layout and sizes of the stiffeners in heavy-duty box girder could make this kind of the structure more compact and reasonable, which has certain engineering values. In this study, on the basis of the establishment of parametric finite element model, the function approaching method and gradient search method are combined to form a high-precision optimization algorithm, which makes structural analysis be integrated into the optimization process. The optimization takes the type and location of longitudinal stiffening ribs and the thickness and hole position of transverse diaphragms as design variables, the box girder structural behaviors as constraint conditions, and the total volume as objective function. Finally, the weight is reduced by nearly 7%. More importantly, the new asymmetrical layout of the stiffeners is obtained, the distance between the longitudinal stiffening ribs on the main web and the neutral layer is longer than the distance between the longitudinal stiffening ribs on the secondary web and the neutral layer, and the hole position of transverse diaphragms is close to the secondary web. Compared with the current production of symmetrical layout structure, this layout provides a new idea for the design of stiffeners in the bias-rail box girder.

Photocatalytic removal of chromium(VI) and sulfite using transition metal (Cu, Fe, Zn) doped TiO2 driven by visible light: Feasibility, mechanism and kinetics

Jinghong Zhang,Dong Fu,Shu Qin Wang,Runlong Hao,Yixiao Xie 한국공업화학회 2019 Journal of Industrial and Engineering Chemistry Vol.80 No.-

To cooperatively oxidize sulfite and reduce Cr(VI), this paper proposed a visible-light drivenphotocatalytic method, with using the photocatalysts of transition metals (Cu, Fe and Zn) dopedTiO2. The photocatalysts were characterized by means of XRD, BET, SEM and UV–vis. 0.5Cu-TiO2 exhibitedthe best performance, and the existing forms of Ti and Cu were Ti4+/Cu+ and/or Cu-O-Ti. Cu-dopingintroduced an energy level of Cu 3d which was useful in decreasing the band gap and increasing thevisible light utilization. Cu-doping also made the TiO2 grains well dispersed, increased the amount ofhydroxyl group, decreased the grain size and increased the specific surface area, which facilitated theadsorption process. Hydrothermal method (8 h and 180 C) favored the formation of anatase crystal. FT-IRresults revealed that most of produced Cr(III) and sulfate were adsorbed onto the catalyst. Kinetics resultssuggested that the rate constant for Cr(VI) removal was 5.05 10 3 min 1. The photo-produced electrons(e ) and holes (h+) contributed to the reduction of Cr(VI) and oxidation of sulfite, respectively; thecontinual consumption of e and h+ enhanced the separation of the h+-e pairs.

Damage detection of bridge structures under unknown seismic excitations using support vector machine based on transmissibility function and wavelet packet energy

Lijun Liu,Jianan Mi,Yixiao Zhang,Ying Lei 국제구조공학회 2021 Smart Structures and Systems, An International Jou Vol.27 No.2

Since it may be hard to obtain the exact external load in practice, damage identification of bridge structures using only structural responses under unknown seismic excitations is an important but challenging task. Since structural responses are determined by both structural properties and seismic excitation, it is necessary to remove the effects of external excitation and only retain the structural information for structural damage identification. In this paper, a data-driven approach using structural responses only is proposed for structural damage alarming and localization of bridge structures. The transmissibility functions (TF) of structural responses are used to eliminate the influence of unknown seismic excitations. Moreover, the inverse Fourier transform of TFs and wavelet packet transform are used to reduce the influence of frequency bands and to extract the damagesensitive feature, respectively. Based on Support vector machines (SVM), structural responses under ambient excitations are used for training SVM. Then, structural responses under unknown seismic excitations are also processed accordingly and used for damage alarming and localization by the trained SMV. The numerical simulation examples of beam-type bridge and a cablestayed bridge under unknown seismic excitations are studied to illustrate the performance of the proposed approach.

Capacitor voltage change rate based fault localization strategy for modular multilevel converters

Jun Hang,Chengqiang Zhang,Yixiao Wang,Shichuan Ding,Jifeng Zhao 전력전자학회 2024 JOURNAL OF POWER ELECTRONICS Vol.24 No.3

With the widespread application of the modular multilevel converter (MMC) in the fields of electronic and electrical engineering, the open-circuit failure problem of the power devices in submodules (SMs) has become the main factor restricting its stable operation. Therefore, power device open-circuit fault diagnosis is widely studied as the main means to ensure the ongoing and stable operation of MMCs. The existing fault diagnosis approaches on the basis of voltage of capacitor change are only applicable to fault diagnosis under active power conditions. However, in reactive power scenarios, MMC systems have very important applications, such as power grid steady-state reactive power regulation and transient reactive power support. Therefore, an effective fault diagnosis method based on the capacitance voltage change rate is put forward for the diagnosis of faults under reactive conditions. This method diff erentiates the capacitor voltage and compares it with the threshold to diagnose faults under reactive power operation. The proposed method is simulated using PSCAD simulation software. Simulation results verify the practicability of the presented approach.

Comparisons and Correlations of Phenolic Profiles and Anti-oxidant Activities of Seventeen Varieties of Pineapple

Liqing Du,Guangming Sun,Xiumei Zhang,Yuge Liu,Witoon Prinyawiwatkul,Zhimin Xu,Yixiao Shen 한국식품과학회 2016 Food Science and Biotechnology Vol.25 No.2

Major phenolic, β-carotene, and ascorbic acid (AA) contents in 17 pineapple varieties were quantified and compared. Anti-oxidant activities were evaluated using 2,2-Diphenyl-l-picrylhydrazyl (DPPH), 2,2'-Azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS), ferric reducing anti-oxidant power (FRAP), and metal chelating capacity (MCC) assays. MD-2 exhibited the highest AA and total phenolic (TP) contents and DPPH and ABTS assay results, but was lower in β-carotene contents. Ripley had the highest total flavonoid (TF) content with a low AA content. Comte de Pairs exhibited the highest MCC and the lowest FRAP values. TP contents and both DPPH and ABTS activities, FRAP values and both AA contents and DPPH activities, and TF contents and ABTS activities were positively correlated. MD-2 exhibited the greatest diversity of phenolics and highest anti-oxidant activities in all assays. Information included herein can be useful for development of pineapple-based food products containing high levels of health promoting anti-oxidants.

Multidimensional nanomaterials for the control of stem cell fate

Chueng Sy-Tsong Dean,Yang Letao,Zhang Yixiao,Lee Ki-Bum 나노기술연구협의회 2016 Nano Convergence Vol.3 No.23

Current stem cell therapy suffers low efficiency in giving rise to differentiated cell lineages, which can replace the original damaged cells. Nanomaterials, on the other hand, provide unique physical size, surface chemistry, conductivity, and topographical microenvironment to regulate stem cell differentiation through multidimensional approaches to facilitate gene delivery, cell–cell, and cell–ECM interactions. In this review, nanomaterials are demonstrated to work both alone and synergistically to guide selective stem cell differentiation. From three different nanotechnology families, three approaches are shown: (1) soluble microenvironmental factors; (2) insoluble physical microenvironment; and (3) nano-topographical features. As regenerative medicine is heavily invested in effective stem cell therapy, this review is inspired to generate discussions in the potential clinical applications of multi-dimensional nanomaterials.