56 research outputs found

    Modeling and control of smart structures embedded with magnetorheological devices

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    University of Technology Sydney. Faculty of Engineering and Information Technology.Engineering structures are the essence of supporting the development of society. However, quite often do they suffer from hostile dynamic loadings or external disturbances that may affect structural health or function. Modeling and control techniques can be applied to resiliently preserve structural health and function with a low energy cost, which is the main theme of the thesis. Smart structures embedded with semi-active control devices offer a promising solution to the problem, such as the magnetorheological (MR) damper (MRD), pin joint (MRP), and elastomer base isolator (MRE). This study first aims at exploring the solutions to the present problem in system modeling and controller design of MR based systems to effectively damp out unwanted vibrations as well as control the embodied energy level. Multi-variable hysteresis models for these structural members are developed, capable of effectively working in a wide scale of loading amplitude and frequency. The modeling objective is to illustrate the intrinsic nonlinearity with traceable relationships between model parameters and control signals in order to realize the field-controlled method for MR structure systems. Experimental data are obtained from a long-stroke MRD, a recent prototype of MRP and an MRE under different loading conditions for model identification and performance assessment. To achieve robustness, a second-order sliding mode controller is designed and applied to the MRE to provide a real-time feedback control of structures. The performance of the proposed technique is evaluated in the simulation of a seismically excited three-storey benchmark building model. To exploit the frequency domain advantage, this study also focuses on the cyclic dissipation of vibration-induced energy in the smart devices under a controlled magnetic field to analyze the energy relationships of the smart devices in the structures. A frequency-shaped second-order sliding mode controller (FS2SMC) is designed along with a low-pass filter to implement the desired dynamic sliding surface. The proposed controller can shape the frequency characteristics of the equivalent dynamics for the MR structure against induced vibrations, and hence, dissipate the mechanical energy flow within the devices to prevent structural damage. The energy spectra of a 10-floor building subject to four benchmark earthquakes are analyzed in terms of kinetic, damping, strain, and input energies to illustrate the capability of an energy-efficient embedded structure. The merits of FS2SMC in engineering structures can also be verified in a half-car model for reducing the roll angle while adjusting the spectrum to prevent natural modes of the structure under external excitations

    Using MapReduce Streaming for Distributed Life Simulation on the Cloud

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    Distributed software simulations are indispensable in the study of large-scale life models but often require the use of technically complex lower-level distributed computing frameworks, such as MPI. We propose to overcome the complexity challenge by applying the emerging MapReduce (MR) model to distributed life simulations and by running such simulations on the cloud. Technically, we design optimized MR streaming algorithms for discrete and continuous versions of Conway’s life according to a general MR streaming pattern. We chose life because it is simple enough as a testbed for MR’s applicability to a-life simulations and general enough to make our results applicable to various lattice-based a-life models. We implement and empirically evaluate our algorithms’ performance on Amazon’s Elastic MR cloud. Our experiments demonstrate that a single MR optimization technique called strip partitioning can reduce the execution time of continuous life simulations by 64%. To the best of our knowledge, we are the first to propose and evaluate MR streaming algorithms for lattice-based simulations. Our algorithms can serve as prototypes in the development of novel MR simulation algorithms for large-scale lattice-based a-life models.https://digitalcommons.chapman.edu/scs_books/1014/thumbnail.jp

    Advanced Knowledge Application in Practice

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    The integration and interdependency of the world economy leads towards the creation of a global market that offers more opportunities, but is also more complex and competitive than ever before. Therefore widespread research activity is necessary if one is to remain successful on the market. This book is the result of research and development activities from a number of researchers worldwide, covering concrete fields of research

    Applications of MATLAB in Science and Engineering

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    The book consists of 24 chapters illustrating a wide range of areas where MATLAB tools are applied. These areas include mathematics, physics, chemistry and chemical engineering, mechanical engineering, biological (molecular biology) and medical sciences, communication and control systems, digital signal, image and video processing, system modeling and simulation. Many interesting problems have been included throughout the book, and its contents will be beneficial for students and professionals in wide areas of interest

    Advanced Sensors for Real-Time Monitoring Applications

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    It is impossible to imagine the modern world without sensors, or without real-time information about almost everything—from local temperature to material composition and health parameters. We sense, measure, and process data and act accordingly all the time. In fact, real-time monitoring and information is key to a successful business, an assistant in life-saving decisions that healthcare professionals make, and a tool in research that could revolutionize the future. To ensure that sensors address the rapidly developing needs of various areas of our lives and activities, scientists, researchers, manufacturers, and end-users have established an efficient dialogue so that the newest technological achievements in all aspects of real-time sensing can be implemented for the benefit of the wider community. This book documents some of the results of such a dialogue and reports on advances in sensors and sensor systems for existing and emerging real-time monitoring applications

    Intelligent Circuits and Systems

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    ICICS-2020 is the third conference initiated by the School of Electronics and Electrical Engineering at Lovely Professional University that explored recent innovations of researchers working for the development of smart and green technologies in the fields of Energy, Electronics, Communications, Computers, and Control. ICICS provides innovators to identify new opportunities for the social and economic benefits of society.  This conference bridges the gap between academics and R&D institutions, social visionaries, and experts from all strata of society to present their ongoing research activities and foster research relations between them. It provides opportunities for the exchange of new ideas, applications, and experiences in the field of smart technologies and finding global partners for future collaboration. The ICICS-2020 was conducted in two broad categories, Intelligent Circuits & Intelligent Systems and Emerging Technologies in Electrical Engineering

    Novel Approaches for Structural Health Monitoring

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    The thirty-plus years of progress in the field of structural health monitoring (SHM) have left a paramount impact on our everyday lives. Be it for the monitoring of fixed- and rotary-wing aircrafts, for the preservation of the cultural and architectural heritage, or for the predictive maintenance of long-span bridges or wind farms, SHM has shaped the framework of many engineering fields. Given the current state of quantitative and principled methodologies, it is nowadays possible to rapidly and consistently evaluate the structural safety of industrial machines, modern concrete buildings, historical masonry complexes, etc., to test their capability and to serve their intended purpose. However, old unsolved problematics as well as new challenges exist. Furthermore, unprecedented conditions, such as stricter safety requirements and ageing civil infrastructure, pose new challenges for confrontation. Therefore, this Special Issue gathers the main contributions of academics and practitioners in civil, aerospace, and mechanical engineering to provide a common ground for structural health monitoring in dealing with old and new aspects of this ever-growing research field
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