ORCID Profile
0000-0003-0391-3027
Current Organisation
Curtin University
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Publisher: Elsevier BV
Date: 07-2022
Publisher: MDPI AG
Date: 14-05-2021
DOI: 10.3390/MA14102568
Abstract: This paper adopts the method of steel tube wall thickness and strength reduction to simulate corrosion damage. The numerical model of the square concrete-filled steel tube long column (SCFST-LC) under eccentric compression after acid rain corrosion is established in the finite element software, ABAQUS. The reliability and accuracy of the model are verified by comparing it with published relevant experimental results. The failure mode, load-deformation curve, and ultimate compressive load were analysed. Following that, the impacts of section size, yield strength of the steel tube, axial compressive strength of concrete, steel ratio, slenderness ratio, and load eccentricity on its ultimate compressive load are comprehensively investigated. The results demonstrate that the ultimate compressive load of the SCFST-LC decreases significantly with the increase in corrosion rate. The corrosion rate increases from 10 to 40%, and the ultimate bearing capacity decreases by 37.6%. Its ultimate bearing capacity can be enhanced due to the increase in section size, material strength, and steel ratio. In contrast, the ascending slenderness ratio and load eccentricity has harmful effects on the ultimate compressive load of the specimens. Finally, a simplified formula for the axial compressive load of the SCFST-LC under eccentric compression after acid rain corrosion is proposed. The calculation accuracy is high and the deviation of the results is basically within 15%, which is in good agreement with the numerical simulation results.
Publisher: Elsevier BV
Date: 11-2021
Publisher: World Scientific Pub Co Pte Lt
Date: 09-2020
DOI: 10.1142/S021945542042002X
Abstract: Wood utility poles are widely applied in power transmission and telecommunication systems in Australia. Because of a variety of external influence factors, such as fungi, termite and environmental conditions, failure of poles due to the wood degradation with time is of common occurrence with high degree uncertainty. The pole failure may result in serious consequences including both economic and public safety. Therefore, accurately and timely identifying the health condition of the utility poles is of great significance for economic and safe operation of electricity and communication networks. In this paper, a novel non-destructive evaluation (NDE) framework with advanced signal processing and artificial intelligence (AI) techniques is developed to diagnose the condition of utility pole in field. To begin with, the guided waves (GWs) generated within the pole is measured using multi-sensing technique, avoiding difficult interpretation of various wave modes which cannot be detected by only one sensor. Then, empirical mode decomposition (EMD) and principal component analysis (PCA) are employed to extract and select damage-sensitive features from the captured GW signals. Additionally, the up-to-date machine learning (ML) techniques are adopted to diagnose the health condition of the pole based on selected signal patterns. Eventually, the performance of the developed NDE framework is evaluated using the field testing data from 15 new and 24 decommissioned utility poles at the pole yard in Sydney.
Publisher: Hindawi Limited
Date: 16-06-2021
DOI: 10.1002/STC.2810
Publisher: IOP Publishing
Date: 09-10-2020
Abstract: Magneto-rheological (MR) materials and their devices are being rapidly developed and have drawn surge of interest for the potential application in vibration control. Among them, a novel shear-mode rotational MR d er (SM-RMRD) with adaptive variable stiffness and d ing was developed for adaptive structural control in real-time against different types of earthquakes. To make use of this innovative device perfectly, a robust and reliable model should be developed to simulate the nonlinear and hysteretic behaviours for the application in adaptive control. Accordingly, this research initially presents a new phenomenological model to describe the force response of the SM-RMRD. Then, model parameters are estimated based on experimental data of force, displacement and velocity, which were directly or indirectly obtained from the device under different loading protocols. The field dependence of each model parameter is also investigated so that a general model with current-related parameters is acquired for designing the control strategy. Using the current-dependent model of SM-RMRD, a semi-active controller is developed and implemented to the SM-RMRD to produce the feedback control for the structures in real-time. Finally, the effectiveness of proposed control method is appraised by a numerical study, in which an SM-RMRDs-incorporated three-storey building model with different control strategies are subjected to various scaled benchmark earthquakes. The comparison result verifies the excellent capacity of the proposed controller based on the developed phenomenological model in terms of reducing the storey acceleration and inter-storey drift.
Publisher: MDPI AG
Date: 30-06-2019
DOI: 10.3390/IJMS20133216
Abstract: Magnetorheological elastomer (MRE) is a type of magnetic soft material consisting of ferromagnetic particles embedded in a polymeric matrix. MRE-based devices have characteristics of adjustable stiffness and d ing properties, and highly nonlinear and hysteretic force–displacement responses that are dependent on external excitations and applied magnetic fields. To effectively implement the devices in mitigating the hazard vibrations of structures, numerically traceable and computationally efficient models should be firstly developed to accurately present the unique behaviors of MREs, including the typical Payne effect and strain stiffening of rubbers etc. In this study, the up-to-date phenomenological models for describing hysteresis response of MRE devices are experimentally investigated. A prototype of MRE isolator is dynamically tested using a shaking table in the laboratory, and the tests are conducted based on displacement control using harmonic inputs with various loading frequencies, litudes and applied current levels. Then, the test results are used to identify the parameters of different phenomenological models for model performance evaluation. The procedure of model identification can be considered as solving a global minimization optimization problem, in which the fitness function is the root mean square error between the experimental data and the model prediction. The genetic algorithm (GA) is employed to solve the optimization problem for optimal model parameters due to its advantages of easy coding and fast convergence. Finally, several evaluation indices are adopted to compare the performances of different models, and the result shows that the improved LuGre friction model outperforms other models and has optimal accuracy in predicting the hysteresis response of the MRE device.
Publisher: Informa UK Limited
Date: 28-09-2021
Publisher: World Scientific Pub Co Pte Lt
Date: 05-04-2021
DOI: 10.1142/S0219455421501078
Abstract: Adaptive negative stiffness device is one of the promising seismic protection devices since it can generate seismic isolation effect through negative stiffness when it is mostly needed and achieve similar vibration mitigation as a semi-active control device. However, the adaptive negative stiffness device generally combined with linear viscous d ing underpins the drawback of degrading the vibration isolation effect during the high-frequency region. In this paper, a modified adaptive negative stiffness device (MANSD) with the ability to provide both lateral negative stiffness and nonlinear d ing by configuring linear springs and linear viscous d ers is proposed to address the above issue. The negative stiffness and nonlinear d ing are realised through a linkage mechanism. The fundamentals and dynamic characteristics of a SDOF system with such a device are analyzed and formulated using the Harmonic Balance Method, with a special focus on the litude–frequency response and transmissibility of the system. The system with d ing nonlinearity as a function of displacement and velocity has been proven to have attractive advantages over linear d ing in reducing the transmissibility in the resonance region without increasing that in the high-frequency region. The effect of nonlinear d ing on suppressing displacement and acceleration responses is numerically verified under different sinusoidal excitations and earthquakes with different intensities. Compared with linear d ing, the MANSD with nonlinear d ing could achieve additional reductions on displacement and acceleration under scaled earthquakes, especially intensive earthquakes.
Publisher: SAGE Publications
Date: 20-01-2020
Abstract: In recent years, negative stiffness vibration isolation device with nonlinear characteristic has become an emerging research area and attracted a significant amount of attentions in the community due to the promising potentials it brought into the field. Its high-static-low-dynamic stiffness property endows the capacity to realize effective vibration isolation and in the meantime to maintain the system stability. This article presents a comprehensive review of the recent research and developments on negative stiffness vibration isolation device. It begins with an introduction on the concept of negative stiffness and then provides a summary and discussion regarding the realization and characteristics of negative stiffness vibration isolation device. The article places its special interest on the principles, structure design, and device characterisation of different types of negative stiffness vibration isolation devices, including spring type, pre-bucked beam type, magnetism type, geometrically nonlinear structural type, and composite structural type. Besides, the applications of negative stiffness vibration isolation device, as well as negative stiffness d er, are summarized and discussed based on the current state-of-the-art. Finally, the conclusions and further discussion provide highlights of the investigation.
No related grants have been discovered for Huan Li.