bluuebunny/crossref_metadata_2025_split huggingface dataset:
Tall building vibration control using a TM‐MR damper assembly: Experimental results and implementation
Authors: Zemp Rene , de la Llera Juan C. , Roschke Paul 
Published: August 2010

AbstractThis paper summarizes the relevant results of the design, construction, testing, and implementation of a nominal 120 kN magnetorheological damper developed to control a free‐plan tall building in Santiago, Chile, equipped with two 160‐ton tuned masses. Cyclic as well as hybrid simulation tests were performed on the prototype damper. Global building responses using measured MR properties showed good correlation with analytical estimations. Also, a proposed physical controller for the MR damper was validated through hybrid and building pull‐back tests. Its performance is essentially equivalent to that of an LQR controller, but the information needed in its implementation is considerably less. Pull‐back tests of 10 cm amplitude were performed on one mass along the flexible edge of the building and its response controlled using the passive and controlled modes of the MR damper. The MR damper was capable of controlling the TM displacements very effectively, as well as the simulated building response for different ground motions and harmonic excitation. Copyright © 2010 John Wiley & Sons, Ltd.
Simulation of floor response spectra in shake table experiments
Authors: Maddaloni G. , Ryu K. P. , Reinhorn A. M. 
Published: August 2010

AbstractAmong several different experimental techniques, used to test the response of structures and to verify their seismic performance, the shake table testing allows to reproduce the conditions of true effects of earthquake ground motions in order to challenge complex model structures and systems. However, the reproduction of dynamic signals, due to the dynamics of the shake table and of the specimen, is usually imperfect even though closed‐loop control in a shake table system is used to reduce these errors and obtain the best fidelity reproduction. Furthermore, because of the dynamic amplifications in the specimen, the signal recorded at desired locations could be completely different from the expected effect of shake table motion. This paper focuses on the development of practical shake table simulations using additional ‘open loop’ feedforward compensation in form of inverse transfer functions (i.e. the ratio of the output structural response to an input base motion in the frequency domain) in order to obtain an acceptable reproduction of desired acceleration histories at specific locations in the specimen. As the first step, a well‐known global feedforward procedure is reformulated for the compensation of the table motion distortions due to the servo‐hydraulic system. Subsequently, the same concept is extended to the table‐structure system to adjust the shake table input in order to achieve a desired response spectrum at any floor of the specimen. Implementations show how such a method can be used in any experimental facility. Copyright © 2010 John Wiley & Sons, Ltd.
Shaking table test and analysis method on ultimate behavior of slender base‐isolated structure supported by laminated rubber bearings
Authors: Takaoka Eiji , Takenaka Yasuo , Nimura Arinori 
Published: August 2010

AbstractThis paper describes the results of shaking table tests to ascertain the ultimate behavior of slender base‐isolated buildings and proposes a time history response analysis method, which can predict the ultimate behavior of base‐isolated buildings caused by buckling fracture in laminated rubber bearings. In the tests, a base‐isolated structure model weighing 192 kN supported by four lead rubber bearings is used. The experimental parameters are the aspect ratio of height‐to‐distance between the bearings and the shape of and the axial stress on the bearings. The test results indicate that the motion types of the superstructure at large input levels can be classified into three types: the sinking type; the uplift type; and the mixed type. These behaviors depend on the relationship between the static ultimate lateral uplifting force on the superstructure and the lateral restoring characteristics of the base‐isolated story. In the analysis method, bearing characteristics are represented by a macroscopic mechanical model that is expanded by adding an axial spring to an existing model. Nonlinear spring characteristics are used for its rotational, shear, and axial spring. The central difference method is applied to solve the equation of motion. To verify the validity of the method, simulation analysis of the shaking table tests are carried out. The results of the analysis agree well with the test results. The proposed model can express the buckling behavior of bearings in the large deformation range. Copyright © 2010 John Wiley & Sons, Ltd.
An equivalent SDOF system model for estimating the response of R/C building structures with proportional hysteretic dampers subjected to earthquake motions
Authors: Oviedo A. Juan Andrés , Midorikawa Mitsumasa , Asari Tetsuhiro 
Published: August 2010

AbstractFor the purpose of estimating the earthquake response, particularly the story drift demand, of reinforced concrete (R/C) buildings with proportional hysteretic dampers, an equivalent single‐degree‐of‐freedom (SDOF) system model is proposed. Especially in the inelastic range, the hysteretic behavior of an R/C main frame strongly differs from that of hysteretic dampers due to strength and stiffness degradation in R/C members. Thus, the proposed model, unlike commonly used single‐spring SDOF system models, differentiates the restoring force characteristics of R/C main frame and hysteretic dampers to explicitly take into account the hysteretic behavior of dampers. To confirm the validity of the proposed model, earthquake responses of a series of frame models and their corresponding equivalent SDOF system models were compared. 5‐ and 10‐story frame models were studied as representative of low‐ and mid‐rise building structures, and different mechanical properties of dampers—yield strength and yield deformation—were included to observe their influence on the effectiveness of the proposed model. The results of the analyses demonstrated a good correspondence between estimated story drift demands using the proposed SDOF system model and those of frame models. Moreover, the proposed model: (i) led to better estimates than those given by a single‐spring SDOF system model, (ii) was capable of estimating the input energy demand and (iii) was capable of estimating the total hysteretic energy and the participation of dampers into the total hysteretic energy dissipation, in most cases. Results, therefore, suggest that the proposed model can be useful in structural design practice. Copyright © 2010 John Wiley & Sons, Ltd.
Performance‐based seismic assessment method for Taiwanese historic Dieh‐Dou timber structures
Authors: Tsai Pin‐Hui , D'Ayala Dina 
Published: August 2010

AbstractLateral force, response spectrum and step‐by‐step pushover analyses are performed and compared with the post‐earthquake survey of two Dieh‐Dou buildings seriously affected in the 1999 Chi‐Chi earthquake in Taiwan. The results show that the proposed FE model with finite translational and rotational stiffness can successfully be employed to assess the vulnerability of the frames. The fundamental period of Dieh‐Dou structures is about 1.0 s higher than that calculated by the simplified approach of the codes for regular frames; a modal analysis is, therefore, essential for this typology of structure. The elastic analysis, either lateral force or response spectrum, is shown to be reliable to assess Dieh‐Dou frames when quick results are desired. However, a non‐linear step‐by‐step pushover analysis has the advantage of greater accuracy, as it allows mapping the failure trend and indicating the critical elements. The lateral drifts are compared with the actual observed damage pattern and when the damage level is related to the peak ground acceleration on a vulnerability curve plot, it is shown that the joint failure combined with the lateral drift gives an indication of the global structural behaviour of this historic construction typology. Owing to the unique construction features of the Dieh‐Dou, the joint failure represents also a critical criterion in terms of maximum retention for conservation. Based on a damage level approach, an assessment methodology is suggested that would allow optimizing a strengthening strategy, for protection of these precious structures from future earthquakes while avoiding unnecessary interventions. Copyright © 2010 John Wiley & Sons, Ltd.
System identification and damage evaluation of degrading hysteresis of reinforced concrete frames
Authors: Loh Chin‐Hsiung , Mao Chien‐Hong , Huang Jhih‐Ren , Pan Tso‐Chien 
Published: August 2010

AbstractIn this study, signal processing approaches and nonlinear identification are used to measure seismic responses of reinforced concrete (RC) structures using the shaking table test. To analyze structural nonlinearity, an equivalent linear system with time‐varying model parameters, singular spectrum analysis to elucidate residual deformation, and wavelet packet transformation analysis to yield the energy distribution among components are adopted to detect the nonlinearity. Then, damage feature extraction is conducted using both the Holder exponent and the Level‐1 detail of the discrete wavelet component. Finally, the modified Bouc‐Wen hysteretic model and the system identification process are employed to the shaking table test data to evaluate the physical parameters, including the stiffness degradation, the strength deterioration and the pinching hysteresis. Finally, the identified stiffness and strength degradation functions from the test data of RC frames in relation to the degree of ground shaking, damage index and the identified nonlinear features are discussed. Based on the proposed method, both signal‐based and model‐based identifications, the relationship between the damage occurrence and severity of structural damage can be identified. Copyright © 2010 John Wiley & Sons, Ltd.
Evaluating the impact of soil redistribution on the in situ mineralization of soil organic carbon
Authors: Van Hemelryck Hendrik , Govers Gerard , Van Oost Kristof , Merckx Roel 
Published: August 2010

AbstractSoil erosion, transport and deposition by water drastically affect the distribution of soil organic carbon (SOC) within a landscape. Moreover, soil redistribution may have a large impact on the exchange of carbon (C) between the pedosphere and the atmosphere. One of the large information gaps within this research domain, concerns the fate of SOC after erosion by water. According to different (mainly laboratory) studies, soil redistribution leads to aggregate breakdown, thereby exposing the contained SOC to mineralization.Our study aims to quantify the extent to which such increased mineralization occurs in a real field situation. Carbon dioxide (CO2)‐efflux was measured in the field after an important erosion event for a continuous period of 112 days. The specific situation on the field ensured that almost none of eroded SOC was exported from the field. Measurements of CO2‐efflux were done in areas with sediment deposition, as well as in comparable areas without sedimentation. Comparison of these measurements allowed the net effect of soil deposition on CO2‐efflux to be assessed. Field data were complemented by measurements on incubated, undisturbed soil core samples, in order to disentangle the contribution of environmental factors (moisture, temperature) from any erosional effect on CO2‐efflux.Results of these measurements on the field showed that CO2‐efflux was regulated by a complex interplay of different factors (mostly soil porosity, soil moisture and soil temperature).In combination with the incubation measurements, it could be concluded that the processes of erosion and transport indeed led to an increased mineralization of SOC, as a result of aggregate breakdown and exposure of previously encapsulated SOC. This effect was, however, much smaller than observed in previous laboratory studies. Moreover, it was only important in the first weeks, immediately after the erosion event. The calculated net erosional effect on CO2‐efflux represented a mere 1·6% of total SOC, originally present in the soil. Copyright © 2010 John Wiley & Sons, Ltd.
A new method for simulating rigid body motion in incompressible two‐phase flow
Authors: Sanders Jessica , Dolbow John E. , Mucha Peter J. , Laursen Tod A. 
Published: August 2010

AbstractComputational treatment of immersed rigid bodies, especially in the presence of free surfaces and/or breaking waves, poses several modeling challenges. A motivating example where these systems are of interest is found in offshore wave energy harvesting systems, where a floating structure converts mechanical oscillations to electrical energy. In this study, we take the first step in developing a robust computational strategy for treating rigid bodies with possible internal dynamics, such that they may be fully coupled to a fluid environment with free surfaces and arbitrarily large fluid motion.Many schemes for fluid–solid interaction involve formulating and solving all of the equations of motion on a structured cartesian finite difference grid, but with overlaying Lagrangian representation of the solid that is used to track its position. Ultimately, most of these techniques, which include methods for deformable solids as well, solve the equations of motion completely on the Eulerian grid (see, for example, (J. Comput. Phys. 2005; 205:439–457) and (J. Comput. Phys. 2008; 227:3114–3140)). By contrast, we solve Lagrangian‐type rigid body equations coupled with the Eulerian formulation of the Navier Stokes equations for an immersed solid. This departure from the standard method facilitates the addition of the internal dynamics characteristic of power conversion systems. The study is based on a finite difference and level set description of a free surface between two immiscible fluids (for example water and air) for incompressible flow by Summan (J. Comput. Phys. 1994; 114:146–159). Copyright © 2010 John Wiley & Sons, Ltd.
Coupled fluid–solid interaction under shock wave loading
Authors: Tipton D. Gregory , Christon Mark A. , Ingber Marc S. 
Published: August 2010

AbstractThis paper considers the treatment of fluid–solid interaction problems under shock wave loading, where the solid experiences large bulk Lagrangian displacements. This work addresses the issues associated with using a level set as a generalized interface for fluid–solid coupling where the fluid–solid interface is embedded in an unstructured fluid grid. We outline the formulation used for the edge‐based unstructured‐grid Euler solver. The identification of the fluid–solid interface on the unstructured fluid mesh uses a super‐sampled ℒ︁2 projection technique, which in conjunction with a Lagrangian interface position, permits fast identification of the interface and the concomitant imposition of boundary conditions. The use of a narrow‐band approach for the identification of the wetted interface is presented with the details of the construction of interface conditions. A series of two and three‐dimensional shock‐body computations are presented to demonstrate the validity of the current approach on problems with static and dynamic interfaces, including projectile/shock interaction simulations. Copyright © 2010 John Wiley & Sons, Ltd.
Central WENO scheme for the integral form of contravariant shallow‐water equations
Authors: Gallerano F. , Cannata G. 
Published: August 2010

AbstractA new Central Weighted Essentially Non‐Oscillatory scheme for the solution of the shallow‐water equations expressed in contravariant formulation is presented. One of the most efficient methodologies belonging to Central WENO family involves: reconstructions of cell‐averaged values of flow variables, reconstruction of point‐values of flow variables, advancing from time level tn to time level tn+1 of the cell‐averaged values. The extension of the above‐mentioned methodology into the contravariant environment implies that the contravariant shallow‐water equations must be expressed in an integral form. An element of novelty presented in this paper regards the definition of a formal integral expression of the shallow‐water equations in a contravariant formulation, in which the Christoffel symbols are avoided. The WENO reconstructions are performed by a two‐dimensional interpolating procedure taking into account the curved coordinate lines. The proposed scheme ensures the satisfaction of the exact C‐property. Several two‐dimensional test cases are used to verify the good resolution for smooth and discontinuous solutions. Copyright © 2010 John Wiley & Sons, Ltd.
The Runge–Kutta control volume discontinuous finite element method for systems of hyperbolic conservation laws
Authors: Chen Dawei , Yu Xijun , Chen Zhangxin 
Published: August 2010

AbstractIn this paper, a new high‐order and high‐resolution method called the Runge–Kutta control volume discontinuous finite element method (RKCVDFEM) was proposed to solve 1D and 2D systems of hyperbolic conservation laws. Its main advantage lies in the local conservation, and it is simpler than the Runge–Kutta discontinuous Galerkin finite element method (RKDGM). The theoretical analysis showed that the RKCVDFEM has formally an optimal convergence order for 1D systems. Based on logically rectangular grids of irregular quadrilaterals, a scheme for 2D systems was constructed. Some classical problems were simulated and the validity of the method was presented. Copyright © 2010 John Wiley & Sons, Ltd.
Arbitrary Lagrangian–Eulerian 3D ideal MHD algorithms
Authors: Robinson A. C. , Niederhaus J. H. J. , Weirs V. G. , Love E. 
Published: August 2010

AbstractWe discuss algorithmic approaches and verification results associated with the Lagrangian–Eulerian algorithms for ideal magnetohydrodynamics as implemented in the ALEGRA arbitrary Lagrangian–Eulerian code. We discuss the form of the Lagrangian step discretization including the forces and the time step control. We also discuss our constrained transport approach for remap of the magnetic flux density and a deBar‐type approach for total energy conservation which permits the capturing of shocks. We demonstrate the benefit of a predictor–corrector methodology for time discretization. Directions for further research are indicated. Copyright © 2010 John Wiley & Sons, Ltd.
Numerical models for vehicle exhaust dispersion in complex urban areas
Authors: Liu Weiming 
Published: August 2010

AbstractTwo numerical models are presented for predicting vehicle exhaust dispersion in complex urban areas with or without the wind field. The models not only reflect the effect of building and street canyon configuration on the pollutant propagation, but also are able to predict the turbulent energy produced by moving vehicles on the road. In particular, in the discrete model, turbulent energy and pollutant concentration produced by each vehicle are dynamically described in the Lagrangian method. The pollutant propagation is calculated with the advection–diffusion equation. The Reynolds averaged Navier–Stokes equations are numerically solved for the wind flows. The movement and heat release rate of the vehicles are treated as sources of the turbulent energy equation for the computation of turbulent energy produced by the moving vehicles. This paper reports the detailed implementation of the models. Four typical numerical tests were carried out to represent the performance of the proposed numerical models. Copyright © 2010 John Wiley & Sons, Ltd.
An unstructured finite volume model for dam‐break floods with wet/dry fronts over complex topography
Authors: Song Lixiang , Zhou Jianzhong , Li Qingqing , Yang Xiaoling , Zhang Yongchuan 
Published: August 2010

AbstractA robust, well‐balanced, unstructured, Godunov‐type finite volume model has been developed in order to simulate two‐dimensional dam‐break floods over complex topography with wetting and drying. The model is based on the nonlinear shallow water equations in hyperbolic conservation form. The inviscid fluxes are calculated using the HLLC approximate Riemann solver and a second‐order spatial accuracy is achieved by implementing the MUSCL reconstruction technique. To prevent numerical oscillations near shocks, slope‐limiting techniques are used for controlling the total variation of the reconstructed field. The model utilizes an explicit two‐stage Runge–Kutta method for time stepping, whereas implicit treatments for friction source terms. The novelties of the model include the flux correction terms and the water depth reconstruction method both for partially and fully submerged cells, and the wet/dry front treatments. The proposed flux correction terms combined with the water depth reconstruction method are necessary to balance the bed slope terms and flux gradient in the hydrostatical steady flow condition. Especially, this well‐balanced property is also preserved in partially submerged cells. It is found that the developed wet/dry front treatments and implicit scheme for friction source terms are stable. The model is tested against benchmark problems, laboratory experimental data, and realistic application related to dam‐break flood wave propagation over arbitrary topography. Numerical results show that the model performs satisfactorily with respect to its effectiveness and robustness and thus has bright application prospects. Copyright © 2010 John Wiley & Sons, Ltd.
Sensitivity of the 1D shallow water equations with source terms: Solution method for discontinuous flows
Authors: Delenne C. , Finaud‐Guyot P. , Guinot V. , Cappelaere B. 
Published: August 2010

AbstractA finite volume‐based numerical technique is presented concerning the sensitivity of the solution of the one‐dimensional Shallow Water Equations with scalar transport. An approximate Riemann solver is proposed for direct sensitivity calculation even in the presence of discontinuous solutions. The Shallow Water Sensitivity Equations are first derived as well as the expressions of the sensitivity source terms, initial and boundary conditions. The numerical technique is then detailed and application examples are provided to assess the method's efficiency in estimating the sensitivity to different parameters (friction coefficient and initial and boundary conditions). The application of the dam‐break problem to a trapezoidal channel is also provided. The comparison with the analytical solution and the classical empirical approach illustrates the usefulness of the direct sensitivity calculation. Copyright © 2010 John Wiley & Sons, Ltd.
3D simulation of wind turbine rotors at full scale. Part I: Geometry modeling and aerodynamics
Authors: Bazilevs Y. , Hsu M.‐C. , Akkerman I. , Wright S. , Takizawa K. , Henicke B. , Spielman T. , Tezduyar T. E. 
Published: August 2010

AbstractIn this two‐part paper we present a collection of numerical methods combined into a single framework, which has the potential for a successful application to wind turbine rotor modeling and simulation. In Part 1 of this paper we focus on: 1. The basics of geometry modeling and analysis‐suitable geometry construction for wind turbine rotors; 2. The fluid mechanics formulation and its suitability and accuracy for rotating turbulent flows; 3. The coupling of air flow and a rotating rigid body. In Part 2 we focus on the structural discretization for wind turbine blades and the details of the fluid–structure interaction computational procedures. The methods developed are applied to the simulation of the NREL 5MW offshore baseline wind turbine rotor. The simulations are performed at realistic wind velocity and rotor speed conditions and at full spatial scale. Validation against published data is presented and possibilities of the newly developed computational framework are illustrated on several examples. Copyright © 2010 John Wiley & Sons, Ltd.