Wyniki wyszukiwania - BazTech

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Non-destructive detection of high-strength wind turbine bolt looseness using digital image correlation

Xie Wei-Guo, Zhou Peng, Chen Li-Yun, Gu Guo-Qing, Wang Yong-Qing, Chen Yu-Tao

Metrology and Measurement Systems

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2023

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Vol. 30, nr 4

839--850

EN

Looseness of high-strength wind turbine bolts is one of the main types of mechanical failure that threaten the quality and safety of wind turbines, and how to non-destructively detect bolt loosening is essential to accurate assessment of operational reliability of wind turbine structures. Therefore, to address the issue of looseness detection of high-strength wind turbine bolts, this paper proposes a non-destructive detection method based on digital image correlation (DIC). Firstly, the mathematical relationships between the in-plane displacement component of the bolt’s nut surface, the bolt’s preload force loss and the bolt loosening angle are both deduced theoretically. Then, experimental measurements are respectively conducted with DIC with different small bolt loosening angles. The results show that the bolt loosening angle detection method based on DIC has a detection accuracy of over 95%, and the bolt’s preload force loss evaluated by the deduced relationship has a good agreement with the empirical value. Therefore, the proposed DIC-based bolt loosening angle detection method can meet the requirements of engineering inspection, and can achieve quantitative assessment of preload forces loss of wind turbine bolt.

2

Flexible-elastic deformation measurement of ZnS:Cu2+ mechanoluminescent film using visual inspection and digital image correlation

Gu Guo-Qing, Xu Gui-Zhong, Shen Feng, Zhou Peng, Sun Hou-Chao, Weng Jia-Xing

Metrology and Measurement Systems

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2023

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Vol. 30, nr 2

353--365

EN

ZnS-based mechanoluminescent film has been widely used in the fields of stress visualization and stress sensing, due to its high brightness and repeatable stable luminescent characteristics. To evaluate the flexible-elastic deformation performance of ZnS-based mechanoluminescent film, both visual inspection and digital image correlation (DIC) are, respectively, employed for measuring the ZnS-based mechanoluminescent film. ZnS:Cu2+ mechanoluminescent powders are first mixed with polydimethylsiloxane (PDMS) matrix to produce ZnS:Cu2+-PDMS mechanoluminescent film. Then, two measurement experiments are, respectively, conducted to investigate the mechanical response and the flexible-elastic deformation performance of the prepared ZnS:Cu2+-PDMS mechanoluminescent film. On one hand, the mechanical response performance of the ZnS:Cu2+-PDMS mechanoluminescent film is validated by visual monitoring of composite concrete fracture processes. On the other hand, the prepared ZnS:Cu2+-PDMS mechanoluminescent film is also measured by DIC to obtain its full-field deformations and strains information. The flexible-elastic deformation performance of the ZnS:Cu2+-PDMS mechanoluminescent film is well demonstrated by the DIC measured results.

3

Robust zeroing neural networks with two novel power-versatile activation functions for solving dynamic Sylvester equation

Zhou Peng, Tan Mingtao

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2022

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Vol. 70, nr 3

art. no. e141307

EN

In this work, two robust zeroing neural network (RZNN) models are presented for online fast solving of the dynamic Sylvester equation (DSE), by introducing two novel power-versatile activation functions (PVAF), respectively. Differing from most of the zeroing neural network (ZNN) models activated by recently reported activation functions (AF), both of the presented PVAF-based RZNN models can achieve predefined time convergence in noise and disturbance polluted environment. Compared with the exponential and finite-time convergent ZNN models, the most important improvement of the proposed RZNN models is their fixed-time convergence. Their effectiveness and stability are analyzed in theory and demonstrated through numerical and experimental examples.

4

Preparation of Insensitive RDX by Suspension Spray Technology and Its Characterization

Yan Xiang, Li Xiao Dong, Zhou Peng, Ji Wei, Shi Xiao Feng

Central European Journal of Energetic Materials

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2019

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Vol. 16, no. 2

216--227

EN

A new insensitive and high energy explosive based on RDX was prepared by suspension spray technology using Estane 5703 as a binder (e-RDX). Scanning electron microscopy was used to characterize the morphology and particle size of the samples. The composite was analyzed by differential scanning calorimetry and X-ray photoelectron spectroscopy. Its impact sensitivity and detonation velocity were determined. For comparison, raw RDX, refined RDX (r-RDX) and solution spray dried RDX/Estane 5703 (e1-RDX) were also tested using these five methods. The SEM results showed that the e-RDX size was 1-3 μm. e1-RDX exhibited a spherical shape with some defects on the surface. The XPS results indicated that Estane 5703 can be successfully coated onto the surface of e-RDX. Compared to raw RDX, the drop height of r-RDX, e1-RDX and e-RDX was increased, being 16.5 cm, 32.9 cm and 58.4 cm, respectively. The activation energy of e-RDX is lower than that of raw RDX, but a little higher than that of e1-RDX. Compared to raw RDX, the detonation velocity of r-RDX, e1-RDX, w-RDX and e-RDX had decreased, being 110 m·s–1, 710 m·s–1, 410 m·s–1 and 210 m·s–1, respectively.