Vibration Mitigation Systems in Structural Engineering

In all times of history, engineers and architects have searched for opportunities to develop adaptive structures, buildings and building parts, which are equipped for adjusting to ever-changing requirements and conditions. The reasons behind this interest relate to the growing need for functional/ spatial flexibility, sustainability and extended capabilities of structural performance. Recent advancements in construction technology, robotics, architectural computing and material science have increased the interest for these structures/ systems; and allowed us to develop examples that are more advanced. This paper aims to introduce the state of art contemporary adaptive systems in architecture and structural engineering; and presents a future perspective for these systems and their potential applications in the construction industry.

A review study of how adaptive ‘reuse’ and ‘reduce’ will help to bring the sustainable environmental conditions for the current and future generation from the civil engineering—stability and safety point of view, is attempted in this paper. Further using both these different approaches, the knowledge of carbon footprint, embodied energy of the material that forms the core of the structure are understood and judiciously used for its design. The type of methods which are attempted to bring this adaptive reuse and reduce principles of sustainability in the real-life situation through the case study are reviewed. The structural health monitoring system is used to ascertain the standards and procedures that can also help to achieve sustainability to a substantial level is identified. The various types of the structural monitoring system and the various types of algorithms followed to bring the necessary study data for analysis are understood from various papers written already. The use of structural monitoring systems can also facilitate in averting the structural adversity in the infrastructure and buildings. It is understood that the future of civil engineering will have the guidelines and procedures in integrating SHM into the mainstream practice, thereby achieving the requisite sustainable principles for a promising future.KeywordsAdaptive reuseReduceLife cycle analysisStructural monitoringSustainability

Object oriented paradigms for integrated structural engineering

Structural health monitoring and intelligent vibration control of cable-supported bridges: Research and application

The optimal location of renewable distributed generations (DGs) into a radial distribution system (RDS) has attracted major concerns from power system researchers in the present years. The main target of DG integration is to improve the overall system performance by minimizing power losses and improving the voltage profile. Hence, this paper proposed a hybrid approach between an analytical and metaheuristic optimization technique for the optimal allocation of DG in RDS, considering different types of load. A simple analytical technique was developed in order to determine the sizes of different and multiple DGs, and a new efficient metaheuristic technique known as the Salp Swarm Algorithm (SSA) was suggested in order to choose the best buses in the system, proportionate to the sizes determined by the analytical technique, in order to obtain the minimum losses and the best voltage profile. To verify the power of the proposed hybrid technique on the incorporation of the DGs in RDS, it was applied to different types of static loads; constant power (CP), constant impedance (CZ), and constant current (CI). The performance of the proposed algorithm was validated using two standards RDSs—IEEE 33-bus and IEEE 69-bus systems—and was compared with other optimization techniques.

This introductory book presents procedures for the analysis of signals and the characterization of systems in civil engineering. The two main topics of this book are at the core of several fast-growing areas in civil engineering today, including: non-destructive testing, system identification, image processing, local or remote monitoring, smart structures, dynamic loading, and feedback control systems in transportation and structural engineering. The authors have provided the readers with a Web site dedicated to this book which includes readily downloadable algorithms for numerical examples, other examples and applications, and errata. Complete with end-of-chapter exercises, this book is appropriate as an upper undergraduate/graduate level textbook or as a reference source for the research or practicing engineer.

The relationship of stress and strength gradients must be considered simultaneously in analysis of a particular type of fracture. This chapter discusses the principal elastic stress distribution in members of various shapes under different types of pure loads. A basic understanding of both the stress and strength gradients of metal parts with and without stress concentrations and under different types of loading is provided. The chapter also describes the effect of service conditions on applied stresses.

Two types of software that make the handling of huge quantities of data easier are described and compared. The first is an expert system which processes extensive and complicated knowledge. It works interactively with the user when it acquires information which is being compared with the facts and relations contained in the knowledge base. The second type of software is a database system which is a record-keeping system that organizes and maintains information and makes it available on demand. Examples of expert systems and database systems in civil and structural engineering are given.

Buckling analysis of laminated composite plates: Crouzet-Pascal, J. Fibre Science and Technology Vol 11 No 6 (November 1978) pp 413–446

In Memoriam: Dr. Clive L. Dym (1942–2016)

Advances in Engineering Materials, Structures and Systems: Innovations, Mechanics and Applications comprises 411 papers that were presented at SEMC 2019, the Seventh International Conference on Structural Engineering, Mechanics and Computation, held in Cape Town, South Africa, from 2 to 4 September 2019. The subject matter reflects the broad scope of SEMC conferences, and covers a wide variety of engineering materials (both traditional and innovative) and many types of structures. The many topics featured in these Proceedings can be classified into six broad categories that deal with: (i) the mechanics of materials and fluids (elasticity, plasticity, flow through porous media, fluid dynamics, fracture, fatigue, damage, delamination, corrosion, bond, creep, shrinkage, etc); (ii) the mechanics of structures and systems (structural dynamics, vibration, seismic response, soil-structure interaction, fluid-structure interaction, response to blast and impact, response to fire, structural stability, buckling, collapse behaviour); (iii) the numerical modelling and experimental testing of materials and structures (numerical methods, simulation techniques, multi-scale modelling, computational modelling, laboratory testing, field testing, experimental measurements); (iv) innovations and special structures (nanostructures, adaptive structures, smart structures, composite structures, bio-inspired structures, shell structures, membranes, space structures, lightweight structures, long-span structures, tall buildings, wind turbines, etc); (v) design in traditional engineering materials (steel, concrete, steel-concrete composite, aluminium, masonry, timber, glass); (vi) the process of structural engineering (conceptualisation, planning, analysis, design, optimization, construction, assembly, manufacture, testing, maintenance, monitoring, assessment, repair, strengthening, retrofitting, decommissioning). The SEMC 2019 Proceedings will be of interest to civil, structural, mechanical, marine and aerospace engineers. Researchers, developers, practitioners and academics in these disciplines will find them useful. Two versions of the papers are available. Short versions, intended to be concise but self-contained summaries of the full papers, are in this printed book.

This paper shows the variation of different power system parameters for a grid-tied Distributed Generation system during the situation of islanding under different types of load conditions. Parameters that have been taken into account here are RMS voltage, RMS current, Active Power, Reactive Power, Apparent Power, Impedance and Frequency at the Point of Common Coupling (PCC). A fundamental assumption considered here is that the load remains fixed for all the load cases discussed in the result section. The simulation results show the variations in the above parameters for different values and types of loads when islanding occurs in the grid-tied DG power system.

The synthesis of structural health monitoring and vibration control is important in order to provide facilities for constructing smart structures. In recent years, some techniques have been developed to integrate structural identification and optimal vibration control. However, it is still challenging to integrate the identification and vibration control of time-varying structures subject to unknown earthquake excitation. The main difficulties are that structural dynamic responses collected by a simple harmonic motion system are absolute responses under unknown earthquake ground motion while previous identification approaches for unknown external excitation are not applicable for this situation and the need of an efficient algorithm to accurately track the various scenarios of time-varying structures with inexpensive computation to ensure the real-time performance requested by structural vibration control. In this paper, a novel algorithm is presented, in which structural time-varying parameters are treated as ‘virtual unknown inputs’ to the underlying time-invariant structure, a generalized Kalman filter with unknown inputs is proposed for joint identification of joint structural state, unknown earthquake excitation and ‘virtual unknown inputs’ with only partially measured structural absolute responses, and the identification results are integrated in real-time with the instantaneous optimal control scheme to reach the goal of optimal semi-active control provided by magneto-rheological dampers. Some numerical examples of integrated identification and vibration control of various time-varying structures subject to unknown earthquake excitation are used to demonstrate the performances of the proposed algorithm.

In this paper, an innovative hamburger-shaped eddy current damper (HSECD) is presented to mitigate the responses of civil structures subjected to wind excitations. The damper’s capacity to dissipate energy is significantly enhanced through a two-phase configuration of permanent magnets (PMs) and two transmission devices: a ball-screw assembly and a bevel gear group. The improved eddy current damper (ECD) solves the problem that the low damping density of traditional ECDs hinders their application to the field of vibration control for civil structures. First, the construction details of this novel HSECD are elaborated, and its principle is discussed through theoretical analysis and numerical simulation. Subsequently, a prototype of the HSECD was fabricated, and cyclic tensile–compressive tests were conducted to investigate its mechanical performance. Furthermore, the temperature effect on the damper’s maximum output force was analyzed, and more than 10% performance degradation was detected in tests with a continuous loading of 1,250 s, while the damper performance quickly reached a steady state after a certain decline. A theoretical model of the HSECD was then established to simulate its hysteretic characteristics, and the accuracy was verified by comparing it with the test data, where their energy error was only 1.9%. Finally, the application of the HSECD to both a single-degree-of-freedom (SDOF) simplified system and a jacking engineering system demonstrates its excellent control performance because the reduction ratios of their peak displacement were as high as 31.1% and 40.9%, respectively. These results highlight the significant practical value of the HSECD in mitigating the wind-induced vibrations for engineering structures.

Considerable achievements in developing structural regulators as an important method for vibration control have been made over the last few decades. The use of large quantities of cables in traditional wired control systems to connect sensors, controllers, and actuators makes the structural regulators complicated and expensive. A wireless decentralized control experimental platform based on Wi-Fi unit is designed and implemented in this study. Centralized and decentralized control strategies as sample controllers are employed in this control system. An optimal control algorithm based on Kalman estimator is embedded in the dSPACE controller and the DSP controller. To examine the performance of this control scheme, a three-story steel structure is developed with active mass dampers installed on each floor as the wireless communication platform. Experimental results show that the wireless decentralized control exhibits good control performance and has various potential applications in industrial control systems. The proposed experimental system may become a benchmark platform for the validation of the corresponding wireless control algorithm.