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Diagnostics and elimination of airflow separation effects draw essential attention of researchers in the areas of energy generation, civil engineering, and aerospace due to unwanted and harmful interaction of separated airflow with different structures. In aviation, distortion of the intake airflows of an aircraft engine, known as intake separation, not only reduces the efficiency of the engine due

When operating a wind turbine, damage of rotor blades is a serious problem. Undetected damages are likely to increase overtime, and therefore, the safety risks and economical burdens also increase. A monitoring system, which detects reliably defects in early stages, gives scope for action and is therefore a key element to avoid damage increase and to optimize the efficiency of wind turbines. One promising

An effective and reliable approach to updating finite element (FE) models of real structures is to utilize a sensitivity‐based strategy. A challenging issue concerning the sensitivity‐based finite element model updating (FEMU) is to create a well‐established framework for updating the inherent structural properties of FE models under incomplete noisy modal data. When noise contaminates the measured

The aim of this paper is to identify, both through microtremor analysis and visual inspection, the collapse mechanisms of the Nepalese wood‐masonry monuments damaged by the 2015 seismic event that struck Kathmandu and its valley. The research analyses two case studies as the “Radha Krishna” temple located in Teku, a district in Kathmandu, and the “Pancha Deval complex” in Pashupati area. More specifically

Sliding bearings of a bridge are important sliding elements that accommodate the bridge movement caused by temperature action and vehicle/wind load. The sliding life of sliding bearings is determined by the wear of the sliding materials in the bearing. However, the wear of sliding bearings primarily results from a large amount of cumulative sliding displacement experienced by the sliding bearing, even

Nonlinear ultrasonic experiments typically require digital pass‐band filters and advanced signal processing tools to highlight low‐amplitude nonlinear elastic effects such as harmonics, subharmonics, and sidebands, which are used as signatures for the presence of damage. However, current signal processing techniques cannot be used with dual periodic excitation without reducing signal frequency resolution

During strong earthquakes, structural pounding may occur between structures (buildings, bridges, strategic facilities, critical equipment, etc.) and the surrounding moat wall because of the limited separation distance and the deformations of the isolator. An arrangement that favors the solution of this problem is the interposition of shock absorbers. Thus, the influence of geometrical and mechanical

An innovative semiactive device, named the spindle adaptive tuned vibration absorber (SATVA), is proposed herein, having the potential of attenuating unfavorable vibrations of the host systems. The proposed device includes a preferably spindle‐shaped body of mass, whose mass moment of inertia can be altered simply by moving a pair of rotating supports. Therefore, the natural frequency of the device

In this study, a method of predicting the seismic responses of building structures based on a convolutional neural network (CNN) is proposed. In the method, the time histories of acceleration responses previously measured in a building during earthquakes are used in the CNN input layer, with the corresponding time histories of the displacement responses being used in the CNN output layer. The correlations

Expansion joints of bridges are vulnerable to damage due to the thermal expansion and contraction, vehicle traffic, and so forth. Currently, the temperature–displacement relationship model may be the only qualitative method for condition evaluation of bridge expansion joints using the field monitoring data. The quantitative assessment based on the finite element model updating techniques is heavy computational

The accuracy of structural damage identification is affected by the uncertainties in the vibration measurements and the finite element modeling. This paper proposes a novel approach based on sparse deep belief network (DBN) for structural damage identification with uncertain and limited data. Vibration characteristics, that is, natural frequencies and mode shapes, are extracted as the input to the

Interactions among an inerter, spring, and energy dissipation element (EDE) in an inerter system can result in a higher energy dissipation efficiency compared to a single identical EDE, which is referred to as the damping enhancement effect. Previous studies have mainly concentrated on the vibration mitigation effect of the inerter system without an explicit consideration or utilization of the damping

Time series models have been popularly used in structural damage identification because the model coefficients and residual errors are sensitive to structural damages. As the direct relationship between the time series model coefficients (or residual errors) and damage severity is hard to be established, these methods provide limited information about the location or severity of damage. This study

Research on the process and its mechanism of dam failure is a long‐term focus in dam engineering field. The reasonable analysis and prediction of dam failure are of great significance to improve the level of dam emergency management and reduce the risk of dam break. A cellular automata (CA)‐based approach is introduced to implement the simulation analysis for the process of piping failure and its induced

This study investigates multimode damping effects of a long cable attached with a viscous‐shear damper (VSD). A typical VSD comprises a casing box containing viscous medium and shearing plates with parts submerged in the medium. It dissipates vibration energy through shear deformation of the viscous medium. The VSD is low‐cost and invulnerable to leakage or increasing joint play and hence requires

In this paper, a new sensitivity‐based model updating method is presented based on the changes of principal components (PCs) of frequency response function (FRF). Structural damage estimation, identification of damage location and severity, is conducted by an innovative sensitivity relation. The sensitivity relation is derived by incorporating PC analysis (PCA) data obtained from the incomplete measured

Periodic road crack monitoring is an essential procedure for effective pavement management. Highly efficient and accurate crack measurements are key research topics in both academia and industry. Automatic methods gradually replaced traditional manual surveys for more reliable evaluation outputs and better efficiency, whereas the devices are not available to all functional classes of pavements and

This paper develops a disc spring (DS) device to improve the self‐centering capability of a conventional reinforced concrete (RC) shear wall. In particular, the DS devices are installed at the foot of the RC shear wall, thus forming a self‐centering RC shear wall (SCSW) system. The DS devices used in the SCSW system are expected to protect the RC wall from damage and provide restoring force for the

Precast buildings have been becoming popular in China in these 5 years since they have many merits such as effectiveness, safety, high quality, and environmental friendliness. In some cities of China, it is required to make the proportion of precast buildings account for 30% in newly built construction areas. Following the rapid development, their vibration behaviors are attracting more attention since

The long‐term safety and health monitoring of large dams has attracted increasing attention. In this paper, coupling prediction models based on long short‐term memory (LSTM) network are proposed for the long‐term deformation of arch dams. Principal component analysis (PCA) and moving average (MA) method, adopted to make dimension reduction for the input variables, are respectively combined with the

This paper introduces a new and unique full‐scale testbed site for structural health monitoring and soil–structure system identification studies being developed in southwest China. The site is a 48‐story skyscraper with an extended four‐level basement, supported by piles, located in Kunming, the capital of Yunnan Province. Located in the diffused zone of collision of the Indian and Eurasian tectonic

An important issue in impedance‐based damage monitoring is to deploy sensors in proper positions in which damage‐sensitive impedance responses can be captured effectively. In this study, a full‐scale multi‐strand anchorage is analyzed to determine optimal locations of piezoelectric sensors for impedance‐based monitoring of locally damaged strands. First, stress variations of the multi‐strand anchorage

Model updating is used to reduce error between measured structural responses and corresponding finite element (FE) model outputs, which allows accurate prediction of structural behavior in future analyses. In this work, reduced‐order parametrizations of an underlying FE model are developed from singular value decomposition (SVD) of the sensitivity matrix, thereby improving efficiency and posedness

This paper describes a structural health monitoring strategy to detect and classify structural changes in structures that can be equipped with sensors. The proposed approach is based on the ‐distributed stochastic neighbor embedding ( ‐SNE), a nonlinear technique that can represent the local structure of high‐dimensional data collected from multiple sensors in a plane or spatial representation. We

Towards a complete and accurate seismic assessment of a super high‐rise building under bidirectional long‐period ground motions, this study proposes an optimal multi‐type sensor placement framework for the best reconstruction of structural responses and ground motions based on a full‐scale 3D finite element (FE) model of the building. The selected locations and types of sensors are capable of not only

Active vibration control techniques using inertial‐mass actuators have gained some level of acceptance in civil structures. Recent research indicates the effectiveness of this technique in mitigation of human‐induced excitation in pedestrian structures such as floors and footbridges. However, there are some drawbacks associated with the use of inertial‐mass actuators which needs to be dealt with. One

For the swing motion/vibration control of the suspended structural system, the tuned rotary inertia damper (TRID) has been proposed and investigated by the author previously. However it exhibits inherent robustness defect and limited applicability prospect due to its nature of being a passive tuning control system. In this paper, through the integration of active control philosophy with the rotary

The bridge influence line can reflect the structural behavior under moving vehicle loads, which is becoming a proposing tool to study the bridge behavior during service life. A high‐speed vehicle will induce dynamic effect on the bridge, which will significantly change the shape of response curve. It is essential to consider the dynamic response for the accurate identification of the bridge influence

This paper presents a novel structural dynamic nonlinear model and parameter identification method based on the stiffness and damping marginal curves. The stiffness and damping marginal curves are first extracted from the structural dynamic responses. Then, nine nonlinear feature indices (NFIs) are defined based on the marginal curves to describe the characteristics of various nonlinear models. To

The transmission line in a power network is similar to a blood vessel. Any disconnection ultimately affects the transmission of electrical energy, and broken strands and detachment of the fittings are early signs of disconnection. Because aeolian vibration occurs on almost all conductors, an aeolian vibration‐based structural health‐monitoring technology for transmission lines is proposed. First, the

This paper presents a recursive system identification method for MDoF structures with tuned mass dampers (TMDs) considering abrupt stiffness changes in case of sudden events, such as earthquakes. Due to supplementary nonclassical damping of the TMDs, the system identification of MDoF + TMD systems disposes a challenge, in particular, in case of sudden events. These identification methods may be helpful

This paper investigates the use of tuned liquid column dampers (TLCDs) for vibration control of spar‐type floating offshore wind turbines (FOWTs). A 17‐degree‐of‐freedom (17‐DOF) aero‐hydro‐servo‐elastic model for the FOWT is first established using multi‐body‐based formulation and the Euler–Lagrangian equation, taking into consideration the full coupling of the blade‐drivetrain‐tower‐spar vibrations

This paper proposes a data‐driven damage detection method based on fixed moving principal component analysis (FMPCA) to analyze structural dynamic responses and monitor the bridge operational condition and the damage occurrence. The damage indices based on principal components (PCs) and eigenvalues can be calculated continuously by applying a fixed moving window. The length of the moving window is

Icing on the surface of wind turbine blades is one of the most critical problems for wind turbines installed at sites in cold climate. It can significantly affect the performance of the entire wind turbine. A number of deicing methods and techniques have been developed to address this problem. However, first of all, timely icing detection and estimation can provide the necessary information, such as

This article presents the dynamic reliability prediction method of the existing steel box girder considering the time‐variant nonlinear correlations among the performance functions for the failure modes at the multiple control monitoring points. Firstly, the multivariate Bayesian dynamic linear model (MBDLM) considering the nonlinear correlations among the multiple variables is built to predict the

Inerter‐based dampers (IBDs) have been proposed to enhance the efficiency of conventional tuned mass dampers (TMDs) in controlling wind‐induced vibration of civil structures recently. In this paper, four different IBDs, with each featuring a specific combination of dashpot–spring elements in series or in parallel with the inerter device, are applied to control the vortex‐induced vibration (VIV) of

Acoustic emission (AE) technology is extensively acknowledged as a promising structural health monitoring (SHM) approach; meanwhile, AE monitoring has long been criticised for a lack of quantitative results. This work revealed a strong correlation between the shear stress distribution and the resulting AE distribution, enabling accurate and real‐time quantification of the shear stress states in concrete

An innovative subsystem with the incorporation of eddy current (EC) damping and magnetic negative stiffness spring (MNSS) is proposed to develop feasible strategies for performance improvement of existing base isolation techniques. The concept of integrating the eddy current damping mechanism and the nonlinear negative stiffness spring is firstly introduced for better energy transition behavior under

When damaged, it is not unusual to observe nonlinear responses in previously linear structures. Specifically, in rotating machinery context, unbalance, misalignment, bearing, and shaft damage occur during operation, and their responses arise as a combination of multiple modes and harmonics. These vibration effects are undesirable and, besides compromising the system performance, can propagate or generate

Damage in the precast concrete piles occurs mostly during installation. The wave propagation‐based nondestructive testing (NDT) is commonly used to estimate the effective length of the pile after installation and to detect pile damage. However, information extracted from this type of diagnosis is limited and subjective. Whereas, the vibration‐based NDT could provide a comprehensive automatic pile health

Structural health monitoring systems for the localisation of acoustic emission (AE) events have been developed in the past few years for aircraft components. However, these systems still require complex and heavy electrical wiring for each sensing device and sophisticated algorithms for the localisation of AE signals, which inevitably increases both weight and costs. This paper reports the creation

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The safe operation of bridges in service is a worldwide problem; thus, it is significant to ensure the health and stability of bridge structures. For large bridges, considerable progresses have been made in theoretical research and monitoring system. Since the inherent characteristics of medium–small span bridges, such as low cost and minute deformation, the methods applied to large bridges are not

Pipeline blockage can result in the reduction of system carrying capacity, energy and resource wastage, and potential increase in the probability of occurrence of environmental and health problems. The primary purpose of this paper is to demonstrate a methodology to simulate acoustic wave propagation (AWP) in partially blocked fluid‐filled pipes with flow under different flow velocities. This was achieved

Glass facades and enclosures are highly attractive structures with increasing popularity between architects and engineers. These structures show very specific design requirements so as to guarantee an efficient interaction with the other building components. This is especially true in the case of “adaptive” glass systems, with continuously changing configurations according to a given design criteria

The KDamper is a novel passive vibration absorption concept based essentially on the optimal combination of appropriate stiffness elements, one of which has a negative value. In this paper, the implementation of the KDamper as a seismic Absorption Base (KDAB) is considered. The performance of the KDAB is assessed in three characteristic test cases, namely, a rigid body and two flexible buildings with

The present study focuses on estimating material nonlinearity and consequently remaining useful life of fatigued specimens using the amplitude‐ and physics‐based material nonlinearity parameters evaluated for Lamb wave motion in plate specimens. The amplitude‐based nonlinearity parameter depends on amplitudes of the Lamb wave harmonics generated due to material nonlinearity. Here, it is employed to

This study presents a new approach for designing optimal sensors layout based on accuracy of defect mapping. It is obtained from combination of the reference‐free damage detection technique and the probability‐based diagnostic imaging method. Considering damage indices based on continuous wavelet transform of sensors signals, the core of this study involves with development of a database of continuous

When an earthquake strikes an area, unless the local infrastructure has a structural health monitoring system, it is difficult to obtain its health condition due to a lack of data. A smartphone could be competently used for many monitoring tasks to gather large amounts of data at a low cost. In this study, a smartphone is used as a sensor to obtain the interstory drift of buildings by recording a video

The purpose of this paper is to estimate the stiffness and strength of damaged rectangular reinforced concrete shear walls after an earthquake using surface crack patterns. Assessing the damage severity of buildings after an earthquake is an important part of the emergency inspection operation of buildings. Expert inspectors tag buildings into two categories of safe or unsafe that are usually affected

This study examines two basic substructuring schemes for shake table tests where the dynamics of the table is significantly affected by a specimen. The hybrid simulation (HS) scheme, commonly adopted in substructuring experiments, directly uses the output of a numerical substructure as an input signal to a physical substructure. The dynamical substructuring system (DSS) scheme, developed long after

Identifying structural damage can usually be modeled as a problem with the use of linear equations. Due to measurement noise and spatial incompleteness of the measured mode shapes, these linear equations are usually ill conditioned, which will significantly reduce the accuracy of subsequent damage assessment. This study develops an iterative total least squares (TLS) based estimation method, which

Identification of nonlinear hysteretic systems has practical significance for the prediction of structural response. This paper develops a novel parameter identification method for nonlinear hysteretic systems. The Bouc–Wen model and its improved models are used to parametrically characterize the structural systems. Model parameters are identified using a given load‐displacement trajectory. The proposed

A scalable optimal control method for structural vibration mitigation is studied. The method relies on a structure's partitioning that leads to a set of dynamically interconnected subsystems. Each subsystem is operated with an individual subcontroller that collects the local state information and collaborates with the neighboring subcontrollers to estimate a short time prediction of the interconnecting

Due to their low inherent damping and high lateral flexibility, stay cables are prone to large amplitude vibrations governed by either a single or multiple cable modes. Among the practical measures, the installation of transverse passive dampers near the cable‐deck anchorage is a popular choice. Compared to conventional positive stiffness and zero stiffness dampers, negative stiffness damper (NSD)

Cracks that develop in railway infrastructural components such as tunnel linings and track systems are not easy to detect on high‐speed rail routes, since inspection time is limited during the daytime and visibility is very poor at night. Meanwhile, cracks to structures such as those above mentioned are strictly monitored and treated to prevent possible malfunction or accident. In this regard, a track

Delamination is a serious form of deterioration in concrete bridge decks. Infrared thermography (IRT) is an advance non‐destructive testing method for concrete bridge deck delamination detection by capturing the absolute thermal contrast (ΔT) on the concrete surface caused by the disruption in heat flow due to subsurface defects. However, as the ambient environmental conditions (e.g. wind velocity

Timely assessment of damages induced to buildings due to an earthquake is critical for ensuring life safety, mitigating financial losses, and expediting the rehabilitation process as well as enhancing the structural resilience where resilience is measured by an infrastructure's capacity to restore full functionality post extreme events. Since manual inspection is expensive, time consuming and risky