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RISS 인기검색어
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- 저자 : Yanfei Guo (검색결과 5 건)
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Yanfei Guo,ZhouSuo Zhang,Wenzhan Yang,Jianbin Cao,Teng Gong 대한기계학회 2021 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.35 No.3
A novel method for early looseness state identification of bolted joint beams is proposed in this paper based on generalized variational mode decomposition (GVMD) and a similarity index. In the proposed method vibration signals are decomposed by GVMD, which has the property of the multiscale and fixed-frequency decomposition. To effectively extract the desired modes, the frequency band allocation is designed through flexibly defining scale parameters and prior center frequencies according to the characteristics of the signal itself and real needs. A new similarity index is formed based on the centroid frequency ratio of sensitive vibration modes to reliably identify early looseness state. The effectiveness of the proposed method is verified by impulse experiments of bolted joint transverse beam and bolted joint vertical beam. The results indicate that compared with other methods, the proposed method can effectively identify the early looseness state of the bolted joint beams, and has a good repeatability.
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Zhenzhen Zhi,Jian Huang,Yanfei Guo,Siwen Lu,Baoguo Ma 대한토목학회 2017 KSCE JOURNAL OF CIVIL ENGINEERING Vol.21 No.5
Phosphorus Gypsum (PG) based Self-Leveling mortar (GSL) is a green and efficient material for floor construction. Its hydration kinetics, rheology property and their effect on mechanical strength of hydrated GSL were crucial to its final application. This study analyzed the effect on setting time of three retarders, namely Protein Salt (PS), Citric Acid (CA), and Sodium Tripolyphosphate (STPP). The fluidity of GSL was investigated individually using three different types of superplasticizer, namely naphthalene (FDN), polycarboxylate (PCE) and melamine (MSF). Finally, the effect of these chemical admixtures on mechanical properties of GSL hardened was examined. Results showed that the optimal contents of PS were 0.1%-0.15% by weight. With 0.1% PS, setting time of GSL retarded to 80min. To reach a maximum fluidity of GSL to 350mm, the optimal contents of PCE, MSF and FDN were 0.2%, 0.6% and 1.0% respectively and corresponding compressive strength of GSL were 54.25MPa, 53MPa and 52.25MPa. Suggesting PCE is the most effective dispersant in PG based GSL system.
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Inhomogeneous bonding state modeling for vibration analysis of explosive clad pipe
Jianbin Cao,Zhousuo Zhang,Yanfei Guo,Teng Gong 국제구조공학회 2019 Steel and Composite Structures, An International J Vol.31 No.3
Early detection of damage bonding state such as insufficient bonding strength and interface partial contact defect for the explosive clad pipe is crucial in order to avoid sudden failure and even catastrophic accidents. A generalized and efficient model of the explosive clad pipe can reveal the relationship between bonding state and vibration characteristics, and provide foundations and priory knowledge for bonding state detection by signal processing technique. In this paper, the slender explosive clad pipe is regarded as two parallel elastic beams continuously joined by an elastic layer, and the elastic layer is capable to describe the non-uniform bonding state. By taking the characteristic beam modal functions as the admissible functions, the Rayleigh-Ritz method is employed to derive the dynamic model which enables one to consider inhomogeneous system and any boundary conditions. Then, the proposed model is validated by both numerical results and experiment. Parametric studies are carried out to investigate the effects of bonding strength and the length of partial contact defect on the natural frequency and forced response of the explosive clad pipe. A potential method for identifying the bonding quality of the explosive clad pipe is also discussed in this paper.
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Non uniform virtual material modeling on contact interface of assembly structure with bolted joints
Jianbin Cao,Zhousuo Zhang,Wenzhan Yang,Yanfei Guo 국제구조공학회 2019 Structural Engineering and Mechanics, An Int'l Jou Vol.72 No.5
Accurate modeling of contact interface in bolted joints is crucial in predicting the dynamic behavior for bolted assemblies under external load. This paper presents a contact pressure distribution based non-uniform virtual material method to describe the joint interface of assembly structure, which is connected by sparsely distributed multi-bolts. Firstly, the contact pressure distribution of bolted joints is obtained by the nonlinear static analysis in the finite element software ANSYS. The contact surface around bolt hole is divided into several sub-layers, and contact pressure in each sub-layer is thought to be evenly. Then, considering multi-asperity contact at the micro perspective, the relationship between contact pressure and interfacial virtual material parameters for each sub-layer is established by using the fractal contact theory. Finally, an experimental platform for the dynamic characteristics testing of a beam lap structure with double-bolted joint is constructed to validate the efficiency of proposed method. It is found that the theoretical results are in good agreement with experimental results by impact response in both time- and frequency-domain, and the relative errors of the first four natural frequencies are less than 1%. Furthermore, the presented model is used to examine the effect of rough contact surface on dynamic characteristics of bolted joint.
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Teng Gong,ZhouSuo Zhang,Xin Luo,Jianbin Cao,Yanfei Guo 대한기계학회 2020 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.34 No.1
In this study, sparsity maximization nonlinear blind deconvolution (NBD) is proposed to identify the vibration sources of satellite systems from mixed vibration signals. The proposed algorithm decomposes NBD into two independent stages, namely, nonlinear compensation and blind deconvolution. Since nonlinear distortion weakens the sparsity of the observed signals, sparsity maximization is introduced to the nonlinear compensation stage. In the blind deconvolution stage, the blind deconvolution algorithm with reference is used to separate the source signals. The proposed algorithm can improve the accuracy of source signal extraction from nonlinear mixed signals of complex mechanical systems. The effectiveness of the proposed method is verified through simulations. An experimental system of aluminum cabin structure is built based on the satellite’s cabin structure. Results show that the proposed algorithm can successfully realize the identification of source signals.
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