Experiment and Finite Element Analysis on the Ultimate Strength of Ring-Stiff ened Tube-Gusset Joints

Xiaolu Li,Xiaomin Xue,Ling Zhang,Xueming Wang,Huchang Wang 한국강구조학회 2019 International Journal of Steel Structures Vol.19 No.5

Adding ring-stiff eners is an eff ective strategy for strengthening CHS tubular joints. However, research on the capacity of ring-stiff ened CHS tube-gusset joints remains limited. In this study, we performed experimental and numerical analyses to derive static strength equations for this joint. For convenience, we simplifi ed the complex joint model into a ring plate to CHS joint, which consisted of a CHS tube and a ring-stiff ener. First, we tested fi ve specimens to obtain failure mode and ultimate strength. Second, a fi nite element model was established and validated by the experimental results. Then, we used the verifi ed numerical method to simulate the behavior of the ring plate to CHS joint. A wide range of geometric parameters was considered, and the relevant design guide was assessed. Finally, nonlinear analysis was performed, and a design formula was proposed. Good agreement was achieved between the proposed design formula and the results of experimental and numerical analyses.

Risk Assessment of Power System Security based on a Hybrid Optimization GP Method

Xiaobin Wu,Hui Li,Xiaolu Chen 보안공학연구지원센터 2015 International Journal of Security and Its Applicat Vol.9 No.12

In this paper, we propose a hybrid optimization algorithm based on Improved Differential Evolution (IDE) algorithm and Gaussian Process (GP). Firstly, the paper constructs the assessment index system using Fault Tree Analysis (FTA) based on the summary and classification of the factors that could affect the power system security. Secondly, establish the risk assessment model of power system security based on the hybrid optimization GP algorithm. Hyper-parameter of GP has a great influence on construction of evaluation model, while conjugate gradient method which is usually used has strong dependence on initial values and is easy to fall into local optimal solution. So the paper uses the IDE algorithm for the traditional Hyper-parameter optimization, then the optimal Hyper-parameter is used to construct evaluation model for power grid security risk assessment. In the process of improvement, this paper adds the local search (Bees accelerated evolution operation) and global search (Bees scout operation) thought of ABC algorithm into the DE algorithm to reduce the population size required by the algorithm. After that, do the risk assessment of power system by using the established assessment model. Finally, do the simulation experiments using the standard data IEEE-39 and IEEE-118 bus example, and besides compare the IDE-GP with other optimization model like ABC-GP, DE-GP, MA-GP, GA-GP, and the experimental results show that hybrid optimization algorithm has better performance in accuracy while the time-consuming difference is minor. The validity of the proposed method is also demonstrated.

Comparative experimental study of ethanol-air premixed laminar combustion characteristics by laser induced spark and electric spark ignition

Cangsu Xu,Yangyang Hu,Xiaolu Li,Xuan Zhou,Anhao Zhong 한국화학공학회 2017 Korean Journal of Chemical Engineering Vol.34 No.2

An experimental study of laminar combustion characteristics of ethanol-air premixed mixtures was conducted with different ignition methods, including laser induced spark ignition (LISI) and electric spark ignition (SI) at an initial condition of 358 K temperature and 0.1MPa pressure. Flame propagation with the two different ignition methods was analyzed and discussed. The laminar flame speed was extrapolated with a nonlinear extrapolation method. Results indicate that the laminar speed of ethanol-air mixtures with LISI is faster than that with SI at lean mixtures, but slower at stoichiometric and rich mixtures. The peak values of the laminar burning velocity for SI and LISI with nonlinear extrapolation are 50.1 cm/s and 47.6 cm/s at the equivalence ratio of 1.1, respectively. Laser-induced spark ignition is able to ignite leaner ethanol-air mixtures.

Content-Based Social Network User Interest Tag Extraction

Mei Yu,Xu Han,Xiaolu Gou,Jian Yu,Fang Lv,Jingyu Li 보안공학연구지원센터 2015 International Journal of Database Theory and Appli Vol.8 No.2

Loss and Efficiency Analysis of the Brushless Direct Current Motor with an Amorphous Stator Core

Lai Yifan,Hu Xiaolu,Shi Guibing,Yu Juntao,Wang Li,Gao Zhifeng 대한전기학회 2023 Journal of Electrical Engineering & Technology Vol.18 No.3

Due to the demand for energy conservation, the loss and efficiency of a brushless direct current (BLDC) motor is investigated. In order to improve the motor efficiency, we make efforts to reduce the loss by replacing the silicon steel (SS) stator with amorphous metal (AM) stator and improving the motor design. The motor performance is analyzed by simulations and experiments, and the processing influence on loss of AM material is also considered. It shows that the performance of the AM core deteriorates due to the stress introduced during the core processing, but the utilization of AM material and the optimization design can improve the motor efficiency by 4.76%. In addition, the weight of the motor is reduced by 11.36% than that of the initial motor. This research can provide a reference for the initial design and performance evaluation of AM BLDC motors.

Electroacupuncture-Modulated MiR106b-5p Expression Enhances Autophagy by Targeting Beclin-1 to Promote Motor Function Recovery After Spinal Cord Injury in Rats

Shuhui Guo,Jianmin Chen,Ye Yang,Xiaolu Li,Yun Tang,Yuchang Gui,Jianquan Chen,Jianwen Xu 대한척추신경외과학회 2023 Neurospine Vol.20 No.3

Objective: Electroacupuncture (EA) has a definite effect on the treatment of spinal cord injuries (SCIs), but its underlying molecular mechanism remains unclear. Meanwhile, MiR-106b-5p is an autophagy- and apoptosis-related microribonucleic acid, but whether it regulates the progression of autophagy and apoptosis in SCIs is yet undetermined. As such, this study aimed to elucidate the involvement of miR-106b-5p in the EA treatment of an SCI. Methods: The miR-106b-5p level was detected by quantitative real-time polymerase chain reaction. In vitro, SH-SY5Y cells were transfected with miR-106b-5p mimics or inhibitors to regulate the miR-106b-5p expression, while in vivo, SCI rats were treated with EA for 7 days at the bilateral Zusanli (ST36) and Jiaji (EX-B2) acupoints. The motor function was evaluated using the Basso-Beattie-Bresnahan (BBB) criteria. Further, autophagic vacuoles, pathological damage, and neuronal cell morphology were observed by transmission electron microscopy, as well as by hematoxylin and eosin and Nissl staining, respectively. Results: The miR-106b-5p level, which can interact directly with Beclin-1 by influencing its expression, as well as the expressions of P62, Caspase-3, and Bax, was upregulated after an SCI, but it decreased after EA. Moreover, the ratio of LC3-II to LC3-I was upregulated after EA. EA can enhance autophagy, reduce neuronal apoptosis, and minimize motor dysfunction and histopathological deficits after an SCI. More importantly, however, all the above effects induced by EA can be reversed after an injection of miR-106-5p agomir to produce an overexpression of miR-106b-5p. Conclusion: EA treatment could downregulate miR-106b-5p to alleviate SCI-mediated injuries by promoting autophagy and inhibiting apoptosis.

Prediction of initiation time of corrosion in RC using meshless methods

Ling Yao,Lingling Zhang,Ling Zhang,Xiaolu Li 사단법인 한국계산역학회 2015 Computers and Concrete, An International Journal Vol.16 No.5

Degradation of reinforced concrete (RC) structures due to chloride penetration followed by reinforcement corrosion has been a serious problem in civil engineering for many years. The numerical simulation methods at present are mainly finite element method (FEM) and finite difference method (FDM), which are based on mesh. Mesh generation in engineering takes a long time. In the present article, the numerical solution of chloride transport in concrete is analyzed using radial point interpolation method (RPIM) and element-free Galerkin (EFG). They are all meshless methods. RPIM utilizes radial polynomial basis, whereas EFG uses the moving least-square approximation. A Galerkin weak form on global is used to attain the discrete equation, and four different numerical examples are presented. MQ function and appropriate parameters have been proposed in RPIM. Numerical simulation results are compared with those obtained from the finite element method (FEM) and analytical solutions. Two case of chloride transport in full saturated and unsaturated concrete are analyzed to test the practical applicability and performance of the RPIM and EFG. A good agreement is obtained among RPIM, EFG, and the experimental data. It indicates that RPIM and EFG are reliable meshless methods for prediction of chloride concentration in concrete structures.

A downhole multi-parameter monitoring system for electrical submersible pump

Miaoxin Jin,Pengmiao Zhang,Gang Li,Qiang Gao,Xiaolu Li,Dianguo Xu 전력전자학회 2015 ICPE(ISPE)논문집 Vol.2015 No.6

In order to achieve online monitoring the downhole information related to ESP working state, an ESP downhole parameters monitoring system based on current loop data transmission method was developed. Compared with other methods, the current loop data transmission method was relatively insensitive to interference in harsh environment. By means of ESP motor’s winding and symmetrical reactance located on the ground, the loop for current transmission could be built. The principle of current loop transmission and involved circuit were introduced. An experiment simulating the hostile downhole environment was conducted to test the transmission effect, by which the reliability and accuracy of current loop data transmission was demonstrated.