76 research outputs found
The evaluation system of green mining based on quantum immune algorithm and neural network
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No full text Lishuang Gong, Baoquan Jin, Hongjuan Zhang, Yan Gao, DongWang and Yu Wang, Anti-disturbance proportional integral attitude control and stabilization of rolling hydraulic position system. Proc IMechE Part I: J Systems and Control Engineering 2017, Vol. 231(2) 117–130. DOI: 10.1177/0959651816687862. SAGE regrets that the ‘Funding’ section of this paper (p. 129) contains errors. The correct funding statement is follows: Funding The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This project was supported by National Natural Science Foundation of China (grant no. 51375327) and Natural Science Foundation of Shanxi Province (grant no. 201601D102026) and Natural Science Foundation of Shanxi Province (grant no. 2013011023-3). </jats:p
Seismic Damage Detection of Moment Resisting Frame Structures Using Time-Frequency Features
No full textTo detect seismic damage of moment resisting frame (MRF) structures, a data-driven method using the fractal dimension (FD) of time-frequency feature (TFF) of structural seismic dynamic responses at measured stories is extended and refined. The TFF is defined as the real part of Gabor wavelet transform of translational interstory displacement, and FD is used to give a quantitative value to describe the calculated TFF. Static condensation method is first used to reduce the degrees-of-freedom (DOFs) of MRF and to express the rotational displacements using translational displacements. For linear MRF, the FDs of TFFs at all stories are the same using the definition of TFF and modal superposition principle. For damaged MRF with plastic hinges at the ends of beams and columns, the force analogy method is implemented to establish transformation matrix from plastic hinge rotations to translational interstory inelastic displacements. Due to the sparseness of the transformation matrix, plastic hinges only generate interstory inelastic displacements, which are low-frequency contents, in the vicinity of plastic hinges. Correspondingly, the FDs of TFFs of interstory displacements with inelastic component are different from the FDs of TFFs of the interstory displacements that do not contain inelastic component. A numerical simulation on a 16-story MRF was conducted. The simulation included 10 cases such as no damage or linear structure, plastic hinges in single-story beams, plastic hinges in single-story columns, plastic hinges in single-story beams and columns, and plastic hinges in multiple story beams and columns. The robustness to measurement noise was also investigated. The seismic damage detection results demonstrated that the proposed method was capable of locating the stories where the plastic hinges occurred
Decentralized identification of nonlinear structure under strong ground motion using the extended Kalman filter and unscented Kalman filter
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life prediction of relay based on wavelet packet transform and RBF neural network
No full textThe performance parameters sequential values of relay is non-stationary time series,In order to predict the working life of relay accurately, this paper improves the wavelet packet transform theory and using the improved wavelet packet transform theory to decompose relay overtravel time runoff of non-stationary characteristics, so that the smooth item and random item separation, for the smooth item,using traditional AR model to predict; for random item, the RBF (radial basis function) neural network prediction model which is based on phase space reconstruction is established to predict. Finally, the results of two predict models were reconstructed through the wavelet packet reconstruction method to predict the original non-stationary runoff series. Through an example verified that this method has higher accuracy and it is an feasible method.</p
Monitoring the Dynamic Response of a Buried Polyethylene Pipe to a Blast Wave: An Experimental Study
No full textAlthough the use of polyethylene (PE) pipelines has become increasingly widespread in recent years, few studies have addressed their seismic design and ability to withstand blast waves. In order to establish their seismic capacity, the dynamic response of buried pipelines subjected to blast waves must be explored in depth. Here, we studied the dynamic response of PE pipes situated near an explosive source. Time histories of dynamic strains were measured by conventional strain gauges after simple waterproof treatment, and pipe and ground vibration velocity curves were obtained. Based on the experimental data, the attenuation law of the peak strains under the conditions of different charge masses and blast center distances was analyzed, and the spectrum characteristics of strain, velocity of the pipe, and ground velocity were studied. The results revealed that a large hoop strain on the PE pipes was produced due to the local impact near the explosive source. We found that peak hoop strain (PHS) or peak axial strain (PAS) had a power attenuation relationship with the scaled distance, and this relationship could also be derived by dimensional analysis. The average frequency of strains had the same attenuation form as the charge mass, which was between 10 Hz and 50 Hz. Additionally, the vibration of the pipe showed a low frequency. We also determined that the attenuation of the average frequency of pipe and ground vibration velocity was closely related to the charge mass and the scaled distance. Pipe peak vibration velocity (PPVV), ground peak particle velocity (GPPV), and the peak dynamic strain of pipe were highly positively correlated, which verifies the feasibility of using GPPV to characterize pipeline vibration and strain level. Thus, a blasting criterion of 10% minimum request strength (MRS) for PE pipe was proposed, which means that the additional PHS or PAS of the dangerous point must be less than 10% MRS, and we also propose limiting the safety distance–charge mass for blasts near buried PE pipelines by the criterion. Some results in this paper can serve as the basis for future in-depth theoretical research
A Simple, but Highly Sensitive, Graphene-based Voltammetric Sensor for Salvianic Acid A Sodium
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