Prediction of Stress Intensity Magnifi cation Factors of a Weld Toe Crack in Load-Carrying Cruciform Fillet Welded Joints Under Axial Loading

Haisheng Zhao,Sengtjhen Lie,Yao Zhang 한국강구조학회 2019 International Journal of Steel Structures Vol.19 No.3

Load-carrying cruciform fi llet welded joint is commonly encountered in on-shore and off shore structures. In this study, the stress intensity magnifi cation factors ( M km ) of such confi guration containing a 3-D semi-elliptical surface crack at the weld toe are analysed using 3-D fi nite element analyses. Due to the non-penetrating fi llet welds at the intersection of the main plate and transverse stiff ener, the M km values are found to be much larger than the corresponding results of non-load-carrying cruciform welded joints. Therefore, a new set M km equations for load-carrying joints are built up using multiple regression analyses, and statistical analyses are carried out to validate the goodness of fi t of these equations. It is noted that the existing British Standard 7910 (BS 7910) assessment equation produces an over-conservative prediction on M km values as compared with the newly proposed M km equations, and the largest over-estimation percentage diff erence is as high as 257.8%.

Coverage Area Optimization Algorithm for Directed Sensing Network Based on Energy Aware

Li HaiSheng,Yang XiuZeng,Li ChunQing 보안공학연구지원센터 2016 International Journal of Grid and Distributed Comp Vol.9 No.7

Target area coverage is the most fundamental goal of WSN (Wireless Sensor Network) application, so the design of energy aware based algorithm for coverage time maximization becomes a core problem of a large network. For this reason, a DECAR (Distributed-energy and Coverage Aware Routing) protocol is proposed in this paper to realize the goal of network coverage maximization. Specifically, the rest energy and the coverage overlapping degree of the nodes are considered during CH (cluster head) selection process so as to provide more opportunities for the nodes with more rest energy or higher coverage overlapping degree to become CH; like this, the nodes with less rest energy will not be selected as CH, thus to avoid shortening the network lifetime due to early failure of these nodes and balance the network energy consumption. Meanwhile, the main data transmission line composed of CHs is constructed in the data transmission stage in order to improve data transmission efficiency. The simulation result shows: compared with CPCP-ea and EEUC protocols, the proposed DECAR protocol can obtain longer network lifetime and better data coverage ratio.

Study on Choice of Diversified R&D Investment Types

Chem Haisheng,Jiang Xueqin,Li Zhuotao,Wu Chendi 인하대학교 정석물류통상연구원 2009 인하대학교 정석물류통상연구원 학술대회 Vol.2009 No.10

Initially this paper introduces the trends of the diversified R&D investment types as well as the basic characteristics of the R&D investment. Then it proves by empirical test that businesses may have greater effects by adopting diversified investment types than single investment type. At the same time it also indicates that the difficulty of R&D investment has increased. In order to improve the efficiency of diversified investment choice, in this paper we detail factors such as market, enterprise, technology, which influence the types of R&D investment choice, and make a conclusion of each influencing factors as well.

Choice strategy of ownership structure on corporate performance decline after technology M&A in the role of constrainsts

Chen Haisheng,Zhou Wei,Liang Mingxia,Lan Hailin 인하대학교 정석물류통상연구원 2009 인하대학교 정석물류통상연구원 학술대회 Vol.2009 No.10

Whether a company"s ownership structure is good or not is often justified by corporate performance and technical efficiency. Statistics in this article finds that among listed companies after technology mergers and acquisitions (M&A), above half of them have short-term benefits decline significantly. Considering the Strong reliance of knowledge transfer on the environment, while taking the restraining level of benefit decline after technology M&A as a short-term evaluation standard for ownership structure choice, this paper researches the critical role of ownership structures in curbing the decrease of benefits after technology M&A. And the empirical data of listed companies indicates that in listed companies with high ownership concentration, the "supporting effect" of majority shareholders" behavior can exert more influence to curb the benefit decline after technology M&A than the "tunneling effect". Moreover, the ownership balance in large degree will confine the majority stockholders" will and behaviro, which therefore can weaken their "support effect"and aggravate the benefit edcline after technology M&A.

The Heuristic Algorithm of Wavelet Image Denoising Based on Rough Set

Song Lan,Lei Lixia,Li Haisheng,Hong Wang 보안공학연구지원센터(IJSIP) 2014 International Journal of Signal Processing, Image Vol.7 No.6

In this paper, we propose a novel approach to explore image denoising for patch based image process. The importance measurement model of Rough Entropy and the importance reduction method of wavelet coefficients are given. This paper combines the rough set theory with the denoising method of wavelet threshold, regarding the high-frequency information blocks in the transform domain as similar ones, and adopting importance Reduction Methods to contract the coefficients. The simulation results show that this method is effective.

Multiobjective reliability-based design optimization approach using the gray system and evidence theory

Jiwei Qiu,Haisheng Luo 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.4

Aimed at the subjectivity of selecting the weight of each objective function in the process of multiobjective reliability-based design optimization (MRBDO), this study proposed a multiobjective weight quantitative analysis method by combining the gray incidence analysis method and evidence theory. This method derived the weight of each objective function from the uncertainty information of design variables, and effectively avoided the subjectivity of weight selection. First, the ideal attribute interval number and the interval number matrix of uncertain design variables were defined based on the gray system theory. On the basis of the definition of the information structure sequence, the gray incidence coefficient (GIC) matrix of measures with ideal attribute deviations was derived. Second, the basic probability assignment of each objective function and model under uncertainty variables was derived based on the DempsterShafer evidence theory. The Dempster-Shafer evidence synthesis rule was used to fuse the multisource evidence information to obtain the weight of each objective function. Then, an MRBDO problem was converted into a single-objective reliability-based design optimization (SRBDO) problem, which is relatively easier to address. Third, the performance measurement analysis (PMA) method was used to transform the reliability constraint into an optimized iterative process, and the MRBDO solution was obtained based on the MATLAB Optimization Toolbox and Symbol Toolbox. Finally, the accuracy and efficiency of the proposed method were verified through a numerical example and a small aeroengine gear reduction system.

Cooperative Control of LQ-Feedback Linearization and Error Port-Hamiltonian System for PMSM with NDOB

Chen Youyuan,Yu Haisheng,Meng Xiangxiang,Ding Hao,Gao Xunkai 대한전기학회 2024 Journal of Electrical Engineering & Technology Vol.19 No.3

In this paper, a novel cooperative controller combining Linear Quadratic optimal control based on feedback linearization (LQ-FL) and state error port-Hamiltonian (EPH) with integral term is proposed for permanent magnet synchronous motor. Firstly, the LQ-FL is presented to ensure rapid dynamic performance, and the EPH method makes up for the shortcomings of the system in steady-state performance. The integral term is utilized to eliminate the position tracking steady-state error. Secondly, the Gaussian function is utilized to coordinate the two controllers and make them play their respective superiorities. Then, a nonlinear disturbance observer is used to resolve the total disturbance caused by parameter changes, modeling errors and external disturbance. Finally, the efectiveness and robustness of the proposed controller are verifed by simulation and experiments.

The Effects of Heating Conditions on the Spray Uniformity of the Mixing Nozzle

Xuran Dong,Yonghong Zhong,Haisheng Fang 한국전기전자재료학회 2020 Transactions on Electrical and Electronic Material Vol.21 No.2

Organic electronic devices such as organic thin-film transistors and organic light-emitting diodes have similar structures, which are composed of various layers with different functions. The thickness and uniformity of the deposited layer quite aff ect the performance of devices. Therefore, it is important to produce a deposited layer with high uniformity. Spray coating is the method which has a unique advantage for high-speed deposition over large areas, and the temperature has a greater infl uence on the uniformity. In order to study the effect of heating temperature on the uniformity, two types of nozzles including internal mixing and external mixing nozzles were studied. The position of the heating surface is set at the top, surrounding and bottom of the fluid zone. The results show that the spray uniformity can be effectively improved when it is heated, while the temperature with the highest uniformity is different.

Fuzzy Sliding Mode Adaptive Backstepping Control of Multiple Motors Winding System Based on Disturbance Observer

He Zhihao,Yu Haisheng 대한전기학회 2022 Journal of Electrical Engineering & Technology Vol.17 No.3

This paper studies multi-motor winding system with strong coupling and easily aff ected by parameters perturbation and load disturbance. First, a fuzzy non-singular fast terminal sliding mode controller and a fuzzy adaptive sliding mode controller are designed to control the speed loop and tension loop of the system respectively, which achieves system dynamic decoupling between speed and tension. Then, an adaptive backstepping controller is designed for the current loop of the system so that the parameters perturbation can be estimated by the adaptive law, which is applied to the feed-forward compensation. At the same time, a disturbance observer is used to estimate the total torque of the motor that includes load disturbance and tension torque. Finally, the simulation and some experimental results demonstrate the superiority of the proposed control algorithm.

Experimental and numerical simulation study on the hydrodynamic characteristics of spherical and irregular-shaped particles in a 3D liquid-fluidized bed

Jian Peng,Wei Sun,Haisheng Han,Le Xie,Yao Xiao 한국화학공학회 2022 Korean Journal of Chemical Engineering Vol.39 No.11

Recently, the fluidized bed has been shown to assist in improving the recovery of coarse minerals during flotation. In this study, the fluidization characteristics of spherical and irregular particles in a three-dimensional liquidsolid fluidized bed were studied by combining experimental and computational fluid dynamics (CFD) methods. Fluidization experiments were performed to investigate the effect of superficial velocity, particle shape, and particle size on solid holdup and bed expansion height. CFD model coupled different drag models for spherical and irregular particles were developed and validated by the experimental data of bed expansion ratio and pressure drop. Based on 3D CFD simulations, the axial and radial direction distributions of solid holdup, axial velocity, as well as granular temperature were obtained. Their distribution characteristics were analyzed and discussed in detail. The reported experimental data and simulation results can improve the understanding of irregular granular liquid-solid fluidized bed and provide a basis for further research on fluidized bed flotation.