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225 results on '"Wei, Hongyu"'

25. Hot Deformation Behavior and Numerical Simulation of 40CrNiMo Steel for Wind Turbine Pulley Shafts.

Author

Wei, Hongyu, Liu, Wensheng, Zhang, Ke, Wei, Wei, Wu, Qun, Zhang, Mingya, Tao, Xiaoping, and Liu, Hongyan

Subjects
*STRAIN rate, *TEMPERATURE distribution, *WIND turbines, *ACTIVATION energy, *DEFORMATIONS (Mechanics)
Abstract

The hot deformation behavior (T = 800–1100 °C, ε˙$$ \dot{\epsilon } $$ = 0.01–10 s−1) of 40CrNiMo steel for wind turbine pulley shafts was studied by Gleeble‐3800 thermomechanical simulator. A constitutive equation and hot processing map are established based on the friction and temperature correction curves. The most available hot processing parameters are determined by combining microstructure analysis. The temperature fields and effective strain fields under different deformation conditions are simulated by Deform‐3D software. The results indicate that the effect of friction on the flow curves is greater than that of temperature rise, the activation energy Q of hot deformation for 40CrNiMo steel calculated based on the theoretical calculation is 368.292 kJ mol−1. The constitutive model based on strain compensation has high accuracy, with an average relative error of 6.65% and a correlation coefficient of 0.987. The optimum hot processing interval is at a deformation temperature of 950–1050 °C and a strain rate of 0.03–0.25 s−1, which has a high‐power dissipation value and avoids the instability region. Additionally, numerical simulation results show that the temperature field distribution is uniform in this deformation range, and the standard deviation of the effective strain is low, making it suitable for hot processing. [ABSTRACT FROM AUTHOR]

Published
2024
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35. Early Warning of Systemic Risk in Commodity Markets Based on Transfer Entropy Networks: Evidence from China.

Author

Zhao, Yiran, Gao, Xiangyun, Wei, Hongyu, Sun, Xiaotian, and An, Sufang

Subjects
COMMODITY exchanges, SYSTEMIC risk (Finance), RUSSIAN invasion of Ukraine, 2022-, PRECIOUS metal industries, ENTROPY
Abstract

This study aims to employ a causal network model based on transfer entropy for the early warning of systemic risk in commodity markets. We analyzed the dynamic causal relationships of prices for 25 commodities related to China (including futures and spot prices of energy, industrial metals, precious metals, and agricultural products), validating the effect of the causal network structure among commodity markets on systemic risk. Our research results identified commodities and categories playing significant roles, revealing that industry and precious metal markets possess stronger market information transmission capabilities, with price fluctuations impacting a broader range and with greater force on other commodity markets. Under the influence of different types of crisis events, such as economic crises and the Russia–Ukraine conflict, the causal network structure among commodity markets exhibited distinct characteristics. The results of the effect of external shocks to the causal network structure of commodity markets on the entropy of systemic risk suggest that network structure indicators can warn of systemic risk. This article can assist investors and policymakers in managing systemic risk to avoid unexpected losses. [ABSTRACT FROM AUTHOR]

Published
2024
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36. Mole‐Inspired Robot Burrowing with Forelimbs for Planetary Soil Exploration.

Author

Zhang, Tao, Wei, Hongyu, Zheng, Hongmin, Liang, Zhaofeng, Yang, Haotian, Zhang, Yinliang, Zhu, Haifei, Guan, Yisheng, Ding, Xilun, Wang, Kunyang, and Xu, Kun

Subjects
PLANETARY exploration, FORELIMB, LIFT (Aerodynamics), SOIL granularity, DISPLACEMENT (Psychology), ROBOTS
Abstract

The biological world serves as a vast reservoir of inspiration for human innovation, particularly in the realm of robotics designed to navigate intricate granular environments. Among these creatures adept at burrowing, the mole stands out due to its exceptional body structure and unparalleled efficiency, surpassing most engineering burrowing systems. Consequently, the mole serves as an ideal model for designing highly efficient burrowing robots. This study introduces a mole‐inspired robot burrowing with forelimbs, specifically designed for planetary soil exploration. By closely examining the distinctive body morphology of moles, a forelimb burrowing mechanism is devised through biomimetic mapping, and its kinematics is thoroughly analyzed. A robot prototype is developed and an experimental setup is constructed to evaluate its burrowing performance. A series of tests are conducted to assess the capabilities of the robot, including forelimb burrowing, robot crawling, and robot burrowing. The results demonstrate that the proposed mole‐inspired burrowing robot is capable of crawling and burrowing to a certain depth using its forelimbs. Although it exhibits some upward displacement, this issue can be mitigated by modifying the head configuration and adjusting the forelimb posture to effectively overcome the vertical stress and lift force exerted by granular soils due to intensity gradient. [ABSTRACT FROM AUTHOR]

Published
2024
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