; Oh+'0HP
$TU Delft Repository search results0TU Delft Repository search results (max. 1000)TU Delft LibraryTU Delft Library@x[d@x[d՜.+,0HPX`hp
x
WorksheetFeuilles de calcul
B=%r8X"1Calibri1Calibri1Calibri1
Calibri 83ffff̙̙3f3fff3f3f33333f33333.~TU Delft Repositoryg $uuidrepository linktitleauthorcontributorpublication yearabstract
subject topiclanguagepublication type publisherisbnissnpatent
patent statusbibliographic noteaccess restrictionembargo datefaculty
departmentresearch group programmeprojectcoordinates)uuid:79ff3197213440578e6cc3239e2f2a7bDhttp://resolver.tudelft.nl/uuid:79ff3197213440578e6cc3239e2f2a7bkIncremental nonlinear control of hydraulic parallel robots: An application to the SIMONA research simulator)Huang, Y. (TU Delft Control & Simulation)Mulder, Max (promotor); Chu, Q. P. (promotor); Pool, D.M. (copromotor); Delft University of Technology (degree granting institution)NIn advanced robotic applications such as robotic locomotion, vehicle and flight simulators, and material test devices, there are higher requirements on stiffness, robustness and power ability for the mechanical structure and the actuator. Hence, it is common for such applications to use parallel manipulators and hydraulic actuators, due to their advantages in these aspects over their counterparts of serialmanipulators and electrical actuators. When highprecision motion control is required for such systems, advanced modelbased controllers, including feedback linearization and adaptive control, have been proposed in stateoftheart studies for both hydraulic and parallel mechanical systems. However, the high complexity, nonlinearity and model uncertainty of these systems raise significant challenges for their motion control accuracy.Parallel Robots; Motion Control; Hydraulic Robots; Force Control; Nonlinear Systems; Model Uncertainty; Robustness; Incremental Nonlinear Dynamic Inversionendoctoral thesis9789402814194)uuid:f3248d26ad5243c2b607049b17550e56Dhttp://resolver.tudelft.nl/uuid:f3248d26ad5243c2b607049b17550e56SMotion equations and attitude control in the vertical flight of a VTOL birotor UAVGarciaNieto, Sergio (Universitat Politcnica de Valncia); VelascoCarrau, Jesus (Universitat Politcnica de Valncia); Paredes Valles, F. (TU Delft Control & Simulation); Salcedo, Jose Vicente (Universitat Politcnica de Valncia); Simarro, Raul (Universitat Politcnica de Valncia)This paper gathers the design and implementation of the control system that allows an unmanned Flyingwing to perform a Vertical TakeOff and Landing (VTOL) maneuver using two tilting rotors (BiRotor). Unmanned Aerial Vehicles (UAVs) operating in this configuration are also categorized as Hybrid UAVs due to their ability of having a dual flight envelope: hovering like a multirotor and cruising like a traditional fixedwing, providing the opportunity of facing complex missions in which these two different dynamics are required. This work exhibits the BiRotor nonlinear dynamics, the attitude tracking controller design and also, the results obtained through HardwareIntheLoop (HIL) simulation and experimental studies that ensure the controller s efficiency in hovering operation.THardwareintheloop; Nonlinear dynamics; Simulation; Tilt rotors; Vertical take offjournal article)uuid:9daf61efdbff4bb1977b0bc553da113dDhttp://resolver.tudelft.nl/uuid:9daf61efdbff4bb1977b0bc553da113drNonlinear dynamic identification of graphene's elastic modulus via reduced order modeling of atomistic simulationsSajadi, B. (TU Delft Dynamics of Micro and Nano Systems); Wahls, S. (TU Delft Numerics for Control & Identification); Hemert, Simon van (Student TU Delft); Belardinelli, P. (TU Delft Dynamics of Micro and Nano Systems); Steeneken, P.G. (TU Delft Dynamics of Micro and Nano Systems; TU Delft QN/Steeneken Lab; Kavli institute of nanoscience Delft); Alijani, F. (TU Delft Dynamics of Micro and Nano Systems)Despite numerous theoretical investigations on the mechanical properties of graphene, an accurate identification of its material behavior is still unattained. One hypothesis for this uncertainty is that modeling graphene as a static membrane cannot describe the strong coupling between mechanics and thermodynamics of this structure. Therefore, characterization methods built < upon static models could not capture these effects. In this paper, we propose a new method for building a reduced order model for the dynamics of thermalized graphene membranes. We apply the proper orthogonal decomposition algorithm on time responses obtained from molecular dynamics simulations. As a result, a set of orthogonal modes is obtained which are then employed to build a reduced order model. The proposed model can describe the motion of the suspended graphene membrane over the whole spatial domain accurately. Moreover, due to its computational efficiency, it is more versatile for exploring the nonlinear dynamics of the system. This model is then employed for studying the nonlinear dynamics of graphene membranes at large amplitudes to extract Young's modulus. The obtained Young's modulus incorporates the effects of nanoscaled thermally induced dynamic ripples and hence, is temperature and size dependent. Our proposed atomistic modal order reduction method provides a framework for studying the dynamics and extracting the mechanical properties of other nanostructures at the molecular level.Elasticity; Graphene; Idenification; Molecular dynamics; Nonlinear dynamics; Proper orthogonal decomposition; Reduced order modelingAccepted Author Manuscript
20200922)uuid:8cea302011214b8cb9564a7fe148f4a1Dhttp://resolver.tudelft.nl/uuid:8cea302011214b8cb9564a7fe148f4a1PHighfrequency stochastic switching of graphene resonators near room temperatureDolleman, R.J. (TU Delft QN/Steeneken Lab; Kavli institute of nanoscience Delft); Belardinelli, P. (TU Delft Dynamics of Micro and Nano Systems); Houri, S. (TU Delft QN/van der Zant Lab; Kavli institute of nanoscience Delft); van der Zant, H.S.J. (TU Delft QN/van der Zant Lab; Kavli institute of nanoscience Delft); Alijani, F. (TU Delft Dynamics of Micro and Nano Systems); Steeneken, P.G. (TU Delft Dynamics of Micro and Nano Systems; TU Delft QN/Steeneken Lab; Kavli institute of nanoscience Delft)(Stochastic switching between the two bistable states of a strongly driven mechanical resonator enables detection of weak signals based on probability distributions, in a manner that mimics biological systems. However, conventional silicon resonators at the microscale require a large amount of fluctuation power to achieve a switching rate in the order of a few hertz. Here, we employ graphene membrane resonators of atomic thickness to achieve a stochastic switching rate of 4.1 kHz, which is 100 times faster than current stateoftheart. The (effective) temperature of the fluctuations is approximately 400 K, which is 3000 times lower than the stateoftheart. This shows that these membranes are potentially useful to transduce weak signals in the audible frequency domain. Furthermore, we perform numerical simulations to understand the transition dynamics of the resonator and use analytical expressions to investigate the relevant scaling parameters that allow highfrequency, lowtemperature stochastic switching to be achieved in mechanical resonators.F2D materials; graphene; NEMS; nonlinear dynamics; Stochastic switching)uuid:61c21b75bda0460ab185dac7459020f4Dhttp://resolver.tudelft.nl/uuid:61c21b75bda0460ab185dac7459020f4fQuadrotor Fault Tolerant Incremental Sliding Mode Control driven by Sliding Mode Disturbance ObserversWang, X. (TU Delft Control & Simulation); Sun, S. (TU Delft Control & Simulation); van Kampen, E. (TU Delft Control & Simulation); Chu, Q. P. (TU Delft Control & Simulation)This paper proposes an Incremental Sliding Mode Control driven by Sliding Mode Disturbance Observers (INDISMC/SMDO), with application to a quadrotor fault tolerant control problem. By designing the SMC/SMDO based on the control structure of the sensorbased Incremental Nonlinear Dynamic Inversion (INDI), instead of the modelbased Nonlinear Dynamic Inversion (NDI) in the literature, the model dependency of the controller and the uncertainties in the closedloop system are simultaneously reduced. This allows INDISMC/SMDO to passively resist a wider variety of faults and external disturbance< s using continuous control inputs with lower control and observer gains. When applied to a quadrotor, both numerical simulations and realworld flight tests demonstrate that INDI based SMC/SMDO has better performance and robustness over NDI based SMC/SMDO, in the presence of model uncertainties, wind disturbances, and sudden actuator faults. Moreover, the implementation process is simplified because of the reduced model dependency and smaller uncertainty variations of INDISMC/SMDO. Therefore, the proposed control method can be easily implemented to improve the performance and survivability of quadrotors in real life.FaultTolerant Control; Incremental Nonlinear Dynamic Inversion; Quadrotor flight tests; Sliding Mode Control; Sliding Mode Disturbance Observer)uuid:118b4d3e2d064ce7b5a8bcc934f0468aDhttp://resolver.tudelft.nl/uuid:118b4d3e2d064ce7b5a8bcc934f0468a*Dynamics of interacting graphene membranes*Dolleman, R.J. (TU Delft QN/Steeneken Lab)ySteeneken, P.G. (promotor); van der Zant, H.S.J. (promotor); Delft University of Technology (degree granting institution)Micro and nanomechanical sensors are indispensable in modern consumer electronics, automotive and medical industries. Gas pressure sensors are currently the most widespread membranebased micromechanical sensors. By reducing their size, their unit costs and energy consumption drops, making them more attractive for integration in new applications. Reducing the size requires the membrane to be as thin as possible, but also very strong. Graphene is the perfect material for such a membrane since it is only one atom thick but also the strongest material ever measured. This dissertation investigates the dynamics of suspended graphene membranes for sensing applications. These sensing applications are not restricted to pressure sensors alone, but the dynamics of graphene can also be used as a sensor for other physical properties. Thus, the topic of this thesis goes into the broader subject of the dynamics of interacting graphene membranes.graphene; twodimensional materials; molybdenum disulfide; nanomechanics; pressure sensors; gas sensors; NEMS; nonlinear dynamics; FabryPerot interferometer; thermal characterization; parametric resonance; stochastic switching; squeezefilm effect; selective permeation; osmosis9789085933694(Casimir PhD Series, DelftLeiden 201839
20191119QN/Steeneken Lab)uuid:23c338a18b3440a689e9997adbdafd75Dhttp://resolver.tudelft.nl/uuid:23c338a18b3440a689e9997adbdafd750Incremental Control of Hybrid Micro Air VehiclesSmeur, E.J.J. (TU Delft Control & Simulation)xHoekstra, J.M. (promotor); de Croon, G.C.H.E. (copromotor); Delft University of Technology (degree granting institution)4Micro Air Vehicles (MAVs) can perform many useful tasks, such as mapping and delivery. For these tasks either rotorcraft are used, which can hover but are not very efficient, or fixed wing vehicles, which are efficient but can not hover. Hybrid MAVs combine the hovering of a rotorcraft with the efficiency of a fixed wing. The reason that these vehicles are not yet widely adopted is that they are very difficult to control.<br/><br/>This thesis addresses the use of Incremental Nonlinear Dynamic Inversion (INDI) for the control of the attitude and velocity of hybrid MAVs. This control method had not been applied in a real world application prior to this thesis, which is why the thesis encompasses the application to a quadrotor at first, which is easier to control than a hybrid MAV.<br/><br/>First, an INDI structure is proposed for the control of the angular accelerations of a quadrotor. I show that the delay that filtering of the angular acceleration produces should also be applied to the measurement of the actuator state. If this is done, the filtering does not appear in the transfer function from virtual control to angular acceleration, which turns out to be equal to the actuator dynamics. It is also shown that a disturbance, or unmodeled dynamics, is compensated with the transfer function of the actuator dynamics multiplied with the applied filter an< d a unit delay. Finally, it is shown how the effects of propeller inertia, which can be very significant in the yaw axis, can be dealt with and how the control effectiveness can be made adaptive. All these findings are validated with experiments on a Bebop quadrotor.<br/><br/>Second, this thesis includes a Weighted Least Squares (WLS) control allocation algorithm with priority management into the INDI controller. This means that for vehicles with coupled control effectors, certain control objectives can be given pri ority upon actuator saturation. This is very important for vehicles with controlled axes that are not very important for the stability of the vehicle, such as the yaw for a quadrotor. It is shown that for a quadrotor doing a 50 degree yaw change, the stability is greatly improved when the yaw axis is given very low priority.<br/><br/>Third, this thesis introduces the control of linear accelerations in all three axes with INDI. The controller does not need a complex model, but instead relies on a measurement of the acceleration. It is shown through a wind tunnel experiment, that the disturbance rejection properties, that were shown for the inner loop, carry over to the control of linear accelerations. It is also shown that the method can be applied outdoors with an offtheshelve GPS receiver. Finally, a nonlinear method of calculating the input increment is derived, which provides only a slight improvement in the tracking of aggressive acceleration commands.<br/><br/>These three things are combined for the INDI control of hybrid MAVs. The result is a single, continuous INDI controller for the attitude, and a single, continuous INDI controller for the velocity of the vehicle. This is achieved by incorporating partial derivatives of the lift vector in the control effectiveness of the pitch and roll angles. Though no transition maneuver is explicitly defined, the transition follows implicitly from the increments in attitude and thrust that are calculated from desired acceleration changes. Further, as the control effectiveness of a hybrid MAV changes dramatically over the flight envelope, the control effectiveness is scheduled as a function of airspeed. When the airspeed is too low to measure, the pitch angle is used for this purpose. To prevent sideslip, a sideslip controller is included, where an estimate of the sideslip angle is obtained from the accelerometer.<br/><br/>Test flights show that the INDI inner and outer loop controllers are indeed capa ble of controlling the attitude and the linear acceleration of the vehicle throughout the flight envelope, within the physical limitations of the vehicle. It is shown that the tracking of accelerations can make the vehicle naturally transition to forward flight and back, and fly in the stall region as necessary. Because of the abstraction that the INDI acceleration control provides, it is straightforward to follow a velocity vector field, for example one that guides the aircraft along a line.<br/><br/>The developed controller can be applied to different tailsitter MAVs with relative<br/>ease, as the model dependency is low. The algorithm may even be applied to<br/>different types of hybrid vehicles, such as quadplanes or tiltwing aircraft, with<br/>minor adjustments.<brbIncremental Nonlinear Dynamic Inversion; Hybrid micro air vehicles; Tailsitter; Control allocation9789461869739)uuid:45f8e12e5d80446d9a977cac403fe1b1Dhttp://resolver.tudelft.nl/uuid:45f8e12e5d80446d9a977cac403fe1b1ODeactivation kinetics of solid acid catalyst with laterally interacting protonsGSengar, A. (Eindhoven University of Technology); Van Santen, Rutger A. (Eindhoven University of Technology); SteurPostma, E. (TU Delft Hybrid, Adaptive and Nonlinear; Eindhoven University of Technology); Kuipers, J.A.M. (Eindhoven University of Technology); Padding, J.T. (TU Delft Intensified Reaction and Separation Systems)alkylation catalysis; solid acid catalysis; catalyst deactivation; laterally interacting protons; kinetics simulations; nonlinear dynamics; site percolationHybrid, Adaptive and Nonl< inear)uuid:dd63017ef3644107adadf5b62187812cDhttp://resolver.tudelft.nl/uuid:dd63017ef3644107adadf5b62187812cVOn the origin of amplitude reduction mechanism in tapping mode atomic force microscopyKeyvani Janbahan, A. (TU Delft Structural Optimization and Mechanics; TNO); Sadeghian, Hamed (TNO; Eindhoven University of Technology); Goosen, J.F.L. (TU Delft Structural Optimization and Mechanics); van Keulen, A. (TU Delft Structural Optimization and Mechanics)The origin of amplitude reduction in Tapping Mode Atomic Force Microscopy (TMAFM) is typically attributed to the shift in resonance frequency of the cantilever due to the nonlinear tipsample interactions. In this paper, we present a different insight into the same problem which, besides explaining the amplitude reduction mechanism, provides a simple reasoning for the relationship between tipsample interactions and operation parameters (amplitude and frequency). The proposed formulation, which attributes the amplitude reduction to an interference between the tipsample and dither force, only deals with the linear part of the system; however, it fully agrees with experimental results and numerical solutions of the full nonlinear model of TMAFM.Continuum mechanics; Intermolecular forces; Newtonian mechanics; Atomic force microscopy; Fourier analysis; Nanopatterning; Nonlinear dynamics
20190420%Structural Optimization and Mechanics)uuid:84f48e813aca466fac7629a65101a543Dhttp://resolver.tudelft.nl/uuid:84f48e813aca466fac7629a65101a543IMathematical modeling of endocrine regulation subject to circadian rhythmMedvedev, Alexander (Uppsala University); Proskurnikov, A.V. (TU Delft Networked CyberPhysical Systems; Russian Academy of Sciences); Zhusubaliyev, Zhanybai T. (Southwest State University)LThe 2017 Nobel Prize in Physiology or Medicine awarded for discoveries of molecular mechanisms controlling the circadian rhythm has called attention to the challenging area of nonlinear dynamics that deals with synchronization and entrainment of oscillations. Biological circadian clocks keep time in living organisms, orchestrating hormonal cycles and other periodic rhythms. The periodic oscillations of circadian pacemakers are selfsustained; at the same time, they are entrainable by external periodic signals that adjust characteristics of autonomous oscillations. Whereas modeling of biological oscillators is a wellestablished research topic, mathematical analysis of entrainment, i.e. the nonlinear phenomena imposed by periodic exogenous signals, remains an open problem. Along with sustained periodic rhythms, periodically forced oscillators can exhibit various irregular behaviors, such as quasiperiodic or chaotic trajectories. This paper presents an overview of the mathematical models of circadian rhythm with respect to endocrine regulation, as well as biological background. Dynamics of the human endocrine system, comprising numerous glands and hormones operating under neural control, are highly complex. Therefore, only endocrine subsystems (or axes) supporting certain biological functions are usually studied. Loworder dynamical models that capture the essential characteristics and interactions between a few hormones can than be derived. Goodwin's oscillator often serves as such a model and is widely regarded as a prototypical biological oscillator. A comparative analysis of forced dynamics arising in two versions of Goodwin's oscillator is provided in the present paper: the classical continuous oscillator and a more recent impulsive one, capturing e.g. pulsatile secretion of hormones due to neural regulation. The main finding of this study is that, while the continuous oscillator is always forced to a periodic solution by a sufficiently large exogenous signal amplitude, the impulsive one commonly exhibits a quasiperiodic or chaotic behavior due to nonsmooth dynamics in entrainment.eBiomedical systems; Entrainment; Hybrid systems; Impulse signals; Nonlinear dynamics; Synchronization Networked CyberPhysical Systems)uuid:e803a245b3074c018f52c3417e5d8ac7Dhttp://r< esolver.tudelft.nl/uuid:e803a245b3074c018f52c3417e5d8ac7RModeling the nonlinear cortical response in EEG evoked by wrist joint manipulationVlaar, M.P. (TU Delft Biomechatronics & HumanMachine Control); Birpoutsoukis, Georgios (Free University of Brussels); Lataire, John (Free University of Brussels); Schouten, A.C. (TU Delft Biomechatronics & HumanMachine Control; University of Twente; Northwestern University); Schoukens, Johan (Free University of Brussels); van der Helm, F.C.T. (TU Delft Biomechatronics & HumanMachine Control; Northwestern University)Joint manipulation elicits a response from the sensors in the periphery which, via the spinal cord, arrives in the cortex. The average evoked cortical response recorded using electroencephalography was shown to be highly nonlinear; a linear model can only explain 10% of the variance of the evoked response, and over 80% of the response is generated by nonlinear behavior. The goal of this study is to obtain a nonparametric nonlinear dynamic model, which can consistently explain the recorded cortical response requiring little a priori assumptions about model structure. Wrist joint manipulation was applied in ten healthy participants during which their cortical activity was recorded and modeled using a truncated Volterra series. The obtained models could explain 46% of the variance of the evoked cortical response, thereby demonstrating the relevance of nonlinear modeling. The high similarity of the obtained models across participants indicates that the models reveal common characteristics of the underlying system. The models show predominantly highpass behavior, which suggests that velocityrelated information originating from the muscle spindles governs the cortical response. In conclusion, the nonlinear modeling approach using a truncated Volterra series with regularization, provides a quantitative way of investigating the sensorimotor system, offering insight into the underlying physiology.uBrain modeling; Kernel; Electroencephalography; Robot sensing systems; Wrist; Estimation; Nonlinear dynamical systems)uuid:7ec081418ea94a7e923cb01d9a367b47Dhttp://resolver.tudelft.nl/uuid:7ec081418ea94a7e923cb01d9a367b47ROn the mechanics and stability of microplates in electrically loaded MEMS devices;Sajadi, B. (TU Delft Structural Optimization and Mechanics)tvan Keulen, A. (promotor); Goosen, J.F.L. (copromotor); Delft University of Technology (degree granting institution)In the last decades, MicroElectroMechanical Systems (MEMS) have drawn immense attention due to their potential use in a wide variety of modern applications, including micromechanical sensors and actuators. MEMS are devices combining mechanical and electrical components between 1 and 100 micrometers, all integrated into a single chip. The performance of these devices hinges on the deflection and movement of these micromechanical components and clearly, improvement and innovation of MEMS require a comprehensive knowledge and indepth understanding of the nonlinear mechanics of these components.<br/><br/>In spite of the simple geometry of common micromechanical components, modeling the mechanics of micromechanical sensors and actuators is rather complex. In particular, the mechanics of microplates in electrostatic MEMS is entangled with two influential sources of nonlinearity namely, geometrical nonlinearity and the nonlinearity due to the presence of the electric field. These sources of nonlinearity are often the origin of instability and failure in MEMS devices, but might also be exploited to achieve, for example, higher sensitivity in the device. In either way, such nonlinearities shall be incorporated in the modeling and design of these micromechanical components. <br/><br/>This thesis provides an investigation on nonlinear mechanics of microplates in electrostatic MEMS devices. Based on the proposed models, we are able to predict some phenomena in microplates that have not been noticed before and to study these aspects in a detailed level which was not possible previously. In particular, based on < total potential energy and a Lagrangian approach, the nonlinear mechanics and stability of a clamped circular microplate in interaction with an electrostatic field is studied. The effects of different loading conditions (i.e. static and dynamic electric potential, and with or without the presence of a differential pressure) on the stability of such a system are addressed. <br/><br/>The results of this study suggest that in presence of a differential pressure the steadystate motion of an electrically actuated microplate can be bistable or even multistable. In fact, a differential pressure can cause additional limit points and an unstable solution branch in the static or dynamic steady state solutions of the system. Saddlenode and period doubling bifurcations are repeatedly observed in the results and are recognized as main mechanisms of pullin. Furthermore, one newly observed critical point in static loading is shown to be highly sensitive to the applied differential pressure suggesting the possibility of employing this limit point for sensing applications.<br/><br/>In addition, this thesis provides a study on analyzing nanoplates within the framework of continuum mechanics. In this regard, the nonlinear vibrations of an electrically actuated graphene resonator is modeled and a methodology is proposed for characterization of its mechanical properties. In addition, the possibility of capturing the scaling effects in the mechanical behavior of nanoplates by employing a nonlocal continuum theory is addressed. As a result, two modification factors for the extensional and bending stiffness of nanoplates are presented to account for the effect of thickness in the nonlocal elasticity formulations. <br/><br/>Finally, the mechanical performance and instability of a microplate as a transducer in surface stress sensing is investigated and an optimized design for such a sensor is proposed. It is shown that using the proposed optimized design, the sensitivity and overall reliability of such capacitive surface stress sensors can be significantly improved. <br/><br/>The proposed techniques for modeling the mechanics of microplates in MEMS devices are simple and computationally efficient. They can provide indepth insight into MEMS behavior and can be useful for designing MEMS with platelike micromechanical components.jStability; MicroPlates; nonlinear dynamics; bifurcation; Electrostatic MEMS; Pullin; nonlinear mechanics9789462338449)uuid:77460fb9b68e4d5aa0c168ba2de710e4Dhttp://resolver.tudelft.nl/uuid:77460fb9b68e4d5aa0c168ba2de710e4tSeismic assessment of existing RC buildings under alternative ground motion ensembles compatible to EC8 and NTC 2008Tanganelli, Marco (University of Florence); Viti, Stefania (University of Florence); Mariani, V. (TU Delft Applied Mechanics); Pianigiani, Maria (University of Florence)OThis work investigates the effects of the choice of different ensembles of ground motions on the seismic assessment of existing RC buildings through nonlinear dynamic analysis. Nowadays indeed, all the main International Seismic Codes provide a soil classification which is based on the shear wave velocity, the soil morphology and the assumed distance from the fault source. Depending on the soil properties, a suitable elastic spectrum is provided as target, defined on the basis of average properties assumed for the soil. An ensemble of ground motions, compatible to the target one, must be selected to perform a nonlinear dynamic analysis. The ensemble can be made by artificial or natural ground motions, compatible with the Code spectrum for the assumed soiltype. Alternatively, the set of ground motions can be assumed as compatible with the bedrock Code spectrum and, subsequently, subjected to site response analysis, i.e. filtered through the specific stratigraphy of the site soil. In this work a comparison among these different approaches, all compatible to the European (Eurocode 8, EC8) and Italian (NTC 2008) Code provisions, has been made on a casestudy, i.e. a real RC Italian building. The seismic respon< se of the casestudy under the assumed seismic inputs, expressed in terms of chord rotation and shear force, has been found by performing a nonlinear dynamic analysis under the different assumed seismic excitations. The comparison has been made in terms of seismic performance, expressed as the ratio between the seismic response found for each structural element and the corresponding capacity. The comparison among the seismic performance found by the application of the different ground motion ensembles pointed out significant differences, which underline the importance of the seismic input choice in the seismic assessment of RC buildings.Ground motions selection; Nonlinear dynamic analysis; Seismic assessment; Seismic input; Seismic response analysis; Spectrum compatible ground motions
20180401Applied Mechanics)uuid:f23d3a7699624f16be8cdab3bdfdb884Dhttp://resolver.tudelft.nl/uuid:f23d3a7699624f16be8cdab3bdfdb884KSecurity Evaluation of the Cyber Networks under Advanced Persistent ThreatsYang, L. (TU Delft Network Architectures and Services); Li, Pengdeng (Chongqing University); Yang, Xiaofan (Chongqing University); Tang, Yuan Yan (University of Macau)Advanced persistent threats (APTs) pose a grave threat to cyberspace, because they deactivate all the conventional cyber defense mechanisms. This paper addresses the issue of evaluating the security of the cyber networks under APTs. For this purpose, a dynamic model capturing the APTbased cyberattackdefense processes is proposed. Theoretical analysis shows that this model admits a globally stable equilibrium. On this basis, a new security metric known as the equilibrium security is suggested. The impact of several factors on the equilibrium security is revealed through theoretical analysis or computer simulation. These findings contribute to the development of feasible security solutions against APTs.ICyberspace; measurement; nonlinear dynamical systems; security; stability"Network Architectures and Services)uuid:adf56cdb84be4f38b8fcfad3e04acad9Dhttp://resolver.tudelft.nl/uuid:adf56cdb84be4f38b8fcfad3e04acad9KNonlinear dynamics for estimating the tip radius in atomic force microscopyRull Trinidad, E. (TU Delft Micro and Nano Engineering); Gribnau, T.W.; Belardinelli, P. (TU Delft Dynamics of Micro and Nano Systems); Staufer, U. (TU Delft Micro and Nano Engineering); Alijani, F. (TU Delft Dynamics of Micro and Nano Systems)The accuracy of measurements in Amplitude Modulation Atomic Force Microscopy (AFM) is directly related to the geometry of the tip. The AFM tip is characterized by its radius of curvature, which could suffer from alterations due to repetitive mechanical contact with the surface. An estimation of the tip change would allow the user to assess the quality during imaging. In this work, we introduce a method for tip radius evaluation based on the nonlinear dynamic response of the AFM cantilever. A nonlinear fitting procedure is used to match several curves with softening nonlinearity in the noncontact regime. By performing measurements in this regime, we are able to maximize the influence of the tip radius on the AFM probe response, and this can be exploited to estimate with good accuracy the AFM tip radius.qAtomic force microscopy; Nonlinear dynamics; Intermolecular forces; Van der Waals forces; Equipment and apparatus
20180921Micro and Nano Engineering)uuid:47632dfc4c6a48608a7bd803d5bc6395Dhttp://resolver.tudelft.nl/uuid:47632dfc4c6a48608a7bd803d5bc6395^Combined optical sizing and acoustical characterization of single freelyfloating microbubblesGLuan, Ying (Erasmus Medical Center); Renaud, Guillaume (Erasmus Medical Center; UPMCSorbonne Universits & CNRS); Raymond, Jason L. (Erasmus Medical Center); Segers, Tim (University of Twente); Lajoinie, Guillaume (University of Twente); Beurskens, Robert (Erasmus Medical Center); Mastik, Frits (Erasmus Medical Center); Kokhuis, Tom J A (Erasmus Medical Center); van der Steen, A.F.W. (TU Delft ImPhys/Acoustical Wavefield Imaging; Erasmus Medical Center); Versluis, Michel (University of < Twente); de Jong, N. (TU Delft ImPhys/Acoustical Wavefield Imaging; Erasmus Medical Center)In this study we present a combined optical sizing and acoustical characterization technique for the study of the dynamics of single freelyfloating ultrasound contrast agent microbubbles exposed to long burst ultrasound excitations up to the milliseconds range. A coaxial flow device was used to position individual microbubbles on a streamline within the confocal region of three ultrasound transducers and a highresolution microscope objective. Brightfield images of microbubbles passing through the confocal region were captured using a highspeed camera synchronized to the acoustical data acquisition to assess the microbubble response to a 1MHz ultrasound burst. Nonlinear bubble vibrations were identified at a driving pressure as low as 50 kPa. The results demonstrate good agreement with numerical simulations based on the shellbuckling model proposed by Marmottant et al. [J. Acoust. Soc. Am. 118, 34993505 (2005)]. The system demonstrates the potential for a highthroughput in vitro characterization of individual microbubbles.PUltranonography; Bubble dynamics; Nonlinear dynamics; Vibration testing; Cameras
20171207#ImPhys/Acoustical Wavefield Imaging)uuid:391303cb1e7141cb98e10d077668a492Dhttp://resolver.tudelft.nl/uuid:391303cb1e7141cb98e10d077668a492oA generalized coherence framework for detecting and characterizing nonlinear interactions in the nervous systemYang, Y. (TU Delft Biomechatronics & HumanMachine Control); Solis Escalante, T. (TU Delft Biomechatronics & HumanMachine Control); van der Helm, F.C.T. (TU Delft Biomechatronics & HumanMachine Control); Schouten, A.C. (TU Delft Biomechatronics & HumanMachine Control)5Objective: This paper introduces a generalized coherence framework for detecting and characterizing nonlinear interactions in the nervous system, namely crossspectral coherence (CSC). CSC can detect different types of nonlinear interactions including harmonic and intermodulation coupling as present in static nonlinearities and also subharmonic coupling, which only occurs with dynamic nonlinearities. Methods: We verified the performance of CSC in model simulations with both static and dynamic nonlinear systems. We applied CSC to investigate nonlinear stimulus response interactions in the human proprioceptive system. A periodic movement perturbation was imposed to the wrist when the subjects performed an isotonic wrist flexion. CSC analysis was performed between the perturbation and brain responses (electroencephalogram, EEG). Results: Both the simulation and the application demonstrated that CSC successfully detected different types of nonlinear interactions. Highorder nonlinearities were revealed in the proprioceptive system, shown in harmonic and intermodulation coupling between the perturbation and EEG for all subjects. Subharmonic coupling was found in some subjects but not all. Conclusion: This paper provides a general tool to detect and characterize nonlinear nature and dynamics of the nervous system. The application of CSC on the experimental dataset indicates a complex nonlinear dynamics in the proprioceptive system. Significance: This novel framework 1) unveils the nonlinear neural dynamics in a more complete way than the existing coherence measures, and 2) is more suitable for estimating the input output relation regarding both phase and amplitude compared to phase synchrony measures (which only consider phase coupling). Subharmonic coupling is reported in human proprioceptive system for the first time.nonlinear dynamics; coherence; crossfrequency coupling; electroencephalogram (EEG); Frequencydomain analysis; Nervous system; Biomedical measurement'Biomechatronics & HumanMachine Control)uuid:6a67595f598343258df9b1f628d4877fDhttp://resolver.tudelft.nl/uuid:6a67595f598343258df9b1f628d4877fNonlinear beam mechanicsWestra, H.J.R.Van der Zant, H.S.J. (promotor)In this Thesis, nonlinear dynamics and nonlinear interactions are studied from a micromechanical point of view. Single an< d doubly clamped beams are used as model systems where nonlinearity plays an important role. The nonlinearity also gives rise to rich dynamic behavior with phenomena like bifurcations, stochastic switching and amplitudedependent resonance frequencies. The theoretical background of micromechanical systems involving the relevant nonlinearities for beams clamped on one (cantilever) or two sides (clampedclamped beam) are discussed in chapter 2. First, the linear response of a mechanical resonator is discussed. Then, the linear equations are extended with nonlinear terms accounting for geometric and inertial effects. Specifically, the origin of the Duffing nonlinearity in the equation of motion of a clampedclamped beam is shown. It is shown that the nonlinearity couples the flexural vibration modes of a beam. Microcantilevers are widely used in mass sensing and force microscopy. At small resonance amplitudes, cantilever motion is described by a harmonic oscillator model, while at high amplitudes, the motions is limited by nonlinearities. In chapter 3, the intrinsic mechanical nonlinearity in microcantilevers is studied. It is shown that although the origin is different, the nonlinearity resembles a Duffing nonlinearity resulting in hysteresis and bistable amplitudes. This bistability is then used to implement a mechanical memory. The bistability of microcantilevers can also be used to study the switching characteristics when noise is applied. Chapter 4 shows the experimental implementation of this stochastic switching of microcantilever motion. It is shown that upon increasing the noise intensity, the switching rate rises exponentially as expected from Kramer's law. However, at higher noise intensities, the switching rate saturates and eventually even decreases, which suggests that the noise influences the dynamical parameters of the system. In chapter 5, we investigate in detail the coupling between the flexural vibration modes of a clampedclamped beam. The coupling arises from the displacementinduced tension. A theoretical model based on the nonlinearity is developed, which is experimentally verified by driving two modes of the beam at high amplitudes and reading out their motion at the two frequencies. The experiments show that the resonance frequency of one flexural mode depends on the amplitude of another flexural mode and the theory is in excellent agreement with the experiments. The nonlinearity not only couples the flexural modes in a clampedclamped beam, but we show in chapter 6 that also the cantilever modes are coupled. Here, the mechanism causing the nonlinearity is different, as there is no displacementinduced tension. The microcantilever is driven using a piezo actuator and its motion is read out using an optical setup. At high vibration amplitudes, the resonance frequency of one mode depends on the amplitude of the other modes. The torsional modes also show nonlinear behavior as evidenced by a frequency stiffening of the response. The modal interactions in a microcantilever can also be used in a allmechanical analogue of a cavityoptomechanics, where one mode is used as a cavity mode, which influences the probe mode. In chapter 7, we show that by exciting at the sum and difference frequencies of the two modes, the $Q$ factor of the probe mode could be suppressed over a wide range. In chapter 8, the interaction between a directly and parametericallydriven resonance mode is studied. Parametric driving means that the spring constant of the beams is modulated at twice the resonance frequency. Clampedclamped beams with an integrated piezoactuator on top, designed for applications as gas sensors, are used in the experiments. First, the parametric amplification and oscillation of the beam is studied, then the motion of a parametricallydriven mode is detected by a change in resonance frequency of the directlydriven mode. There is a linear dependence of the oscillation frequency of the parametricallydriven mode and the resonance frequency of the directlydriven mode. A potential application as a linear frequency convert< er is suggested.,nonlinear dynamics; MEMS; modal interactions
20121107Applied Sciences$Kavli Institute of Nanoscience Delft)uuid:dfaae28fc2dd4bdc82d6a1c1aa98fa26Dhttp://resolver.tudelft.nl/uuid:dfaae28fc2dd4bdc82d6a1c1aa98fa26XPredicting Storm Surges: Chaos, Computational Intelligence, Data Assimilation, EnsemblesSiek, M.B.L.A.Solomatine, D.P. (promotor)Accurate predictions of storm surge are of importance in many coastal areas. This book focuses on datadriven modelling using methods of nonlinear dynamics and chaos theory for predicting storm surges. A number of new enhancements are presented: phase space dimensionality reduction, incomplete time series, phase error correction, finding true neighbours, optimization of chaotic model, data assimilation and multimodel ensembles. These were tested on the case studies in the North Sea and Caribbean Sea. Chaotic models appear to be are accurate and reliable short and midterm predictors of storm surges aimed at supporting decisionmakers for flood prediction and ship navigation. ocean wave prediction; nonlinear dynamics and chaos theory; neural networks; optimization; dimensionality reduction; phase error correction; incomplete time series; multimodel ensemble prediction; datadriven modelling; computational intelligence; hydroinformaticsCRC Press/Balkema!Civil Engineering and GeosciencesWater Management)uuid:cf9119d38bbf489bb734f25c4cd1402aDhttp://resolver.tudelft.nl/uuid:cf9119d38bbf489bb734f25c4cd1402agRobust flight control using incremental nonlinear dynamic inversion and angular acceleration prediction'Sieberling, S.; Chu, Q.P.; Mulder, J.A.This paper presents a flight control strategy based on nonlinear dynamic inversion. The approach presented, called incremental nonlinear dynamic inversion, uses properties of general mechanical systems and nonlinear dynamic inversion by feeding back angular accelerations. Theoretically, feedback of angular accelerations eliminates sensitivity to model mismatch, greatly increasing the robust performance of the system compared with conventional nonlinear dynamic inversion. However, angular accelerations are not readily available. Furthermore, it is shown that angular acceleration feedback is sensitive to sensor measurement time delays. Therefore, a linear predictive filter is proposed that predicts the angular accelerations, solving the time delay and angular acceleration availability problem. The predictive filter uses only references and measurements of angular rates. Hence, the proposed control method makes incremental nonlinear dynamic inversion practically available using conventional inertial measurement units.dynamic inversion; nonlinear dynamic inversion; incremental nonlinear dynamic inversion; NDI; INDI; feedback linearization; robust flight control; angular acceleration predictionAIAAAerospace EngineeringControl and Simulation Division)uuid:5dcb113a162a4b49877fe3e36adb3eabDhttp://resolver.tudelft.nl/uuid:5dcb113a162a4b49877fe3e36adb3eabKMechanical stiffening, bistability, and bit operations in a microcantilever3Venstra, W.J.; Westra, H.J.R.; Van der Zant, H.S.J.We investigate the nonlinear dynamics of microcantilevers. We demonstrate mechanical stiffening of the frequency response at large amplitudes, originating from the geometric nonlinearity. At strong driving the cantilever amplitude is bistable. We map the bistable regime as a function of drive frequency and amplitude, and suggest several applications for the bistable microcantilever, of which a mechanical memory is demonstrated.jcantilevers; elastic constants; mechanical stability; micromechanical devices; nonlinear dynamical systemsAmerican Institute of PhysicsQN/Quantum Nanoscience)uuid:3a9cc83b4e034a4ba83277f0b6eebfd1Dhttp://resolver.tudelft.nl/uuid:3a9cc83b4e034a4ba83277f0b6eebfd1ADesign and control of integrated styrene aniline production plant>Partenie, O.; Van der Last, V.; Sorin Bildea, C.; Altimari, P.gThis paper illustrates the operational difficulties arising from simultaneously performing exothermic and en<dothermic reactions, and demonstrates that a plant can be built and safely operated by integrating the design and plantwide control issues. The behaviour of reactor separation recycle systems carrying the coupled reactions A ?P + Q (endo) and B + Q ? R (exo) is investigated. Irrespective of the control structure, state multiplicity cannot be removed if the intermediate component Q is recycled. Therefore, the chemical reactor should be designed such that the recycle of Q can be avoided without economic penalty. The theoretical findings are applied to the design and control of a plant coupling ethylbenzene dehydrogenation and nitrobenzene hydrogenation for simultaneous production of styrene and aniline. After plant design, a rigorous dynamic model is developed using AspenDynamics. A plantwide control structure is implemented and shown to be able to achieve stable operation. Production rate changes of reasonable magnitude can be achieved by changing the reactorinlet flow rates or bedinlet temperature.Kreaction coupling, design and control, nonlinear dynamics, styrene, aniline
De GruyterDelft University of Technology)uuid:67af3eb2bc2444eebed47701e8698b4dDhttp://resolver.tudelft.nl/uuid:67af3eb2bc2444eebed47701e8698b4dbStructural system reliability analysis of jackup platforms under extreme environmental conditionsDaghigh, M.9Hengst, S. (promotor); Vrouwenvelder, A.C.W.M. (promotor)5extreme loads; system reliability; nonlinear dynamics)uuid:db23e7ceee0c4cb0875503dfdc965d9bDhttp://resolver.tudelft.nl/uuid:db23e7ceee0c4cb0875503dfdc965d9bBLumped impulses, discrete displacements and a moving load analysisKok, A.W.M."Finite element models are usually presented as relations between lumped forces and discrete displacements. Mostly finite element models are found by the elaboration of the method of the virtual work  which is a special case of the Galerkin's variational principle . By application of Galerkin's variational principle to time dependent problems, considering elements bordered by ge()metry and time b()undaries, we obtain relations between lumped impulses and discrete displacements. The analogy with respect to static models which formulates relati()ns between lumped forces and discrete displacements is striking. Models are formulated using linear and quadratic displacement fields with respect to time. Free model parameters are used to manipulate numerical stability, accuracy and numerical damping. These numerical tools are used for the numerical simulation ()f a m()ving vehicle at a rail track structure. The analysis sh()ws the natural way ()f m()delling a moving structure (the train) with respect to a fixed supporting structure (the rail track).vdirect integration methods; finite element models; impulses; nonlinear dynamics,; rail wheel interaction; moving loads)uuid:0ad003efaa3746f382156f37c83af5daDhttp://resolver.tudelft.nl/uuid:0ad003efaa3746f382156f37c83af5daYLumped Pulses and Discrete Displacements: A Physical Way to Understand Numerical DynamicsBlaauwendraad, J. (promotor)=nonlinear dynamics; pavement engineering; earthquake analysisDelft University Press
*+&ffffff?'ffffff?(?)?"dXX333333?333333?U}}}}}}}}}} }
}}}
}}}}}}}}}}}}
@
!
"
#
$
%@
&
'
(
)
*
+
,@

.
(
/
0
1
2
3
4@
5
6
(
7
8
9
:@
;
<
(
/
=
>
?
@
A@
B
C
D
E
F
G
H
I
J
K
L@
M
N
O
P
Q
R
S@
T
(
U
V
W
X
Y @
Z
[
(
\
]
^
_
`
a
@
b
c
(
0
d
e
f
g
h@
i
j
(
/
k
l
m
n
o@
p
q
r
]
s
t
u
v
@
w
x
(
y
z
{

}
~@
(
@
(
@
(
@
(
/
p@
l@
h@
(
h@
(
d@
(
4@
4@
(
,@
!"#$%&'()*+,./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcdefghijklmnopqrstuvwxyz{}~
!"#$%&'()*+,./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcdefghijklmnopqrstuvwxyz{}~
!"#$%&'()*+,./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcdefghijklmnopqrstuvwxyz{}~
!"#$%&'()*+,./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcdefghijklmnopqrstuvwxyz{}~
!"#$%&'()*+,./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcdefghijklmnopqrstuvwxyz{}~
!"#$%&'()*+,./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcdefghijklmnopqrstuvwxyz{}~
!"#$%&'()*+,./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcdefghijklmnopqrstuvwxyz{}~
!"#$%&'()*+,./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcdefghijklmnopqrstuvwxyz{}~>@ddyKyKhttp://resolver.tudelft.nl/uuid:79ff3197213440578e6cc3239e2f2a7byKyKhttp://resolver.tudelft.nl/uuid:f3248d26ad5243c2b607049b17550e56yKyKhttp://resolver.tudelft.nl/uuid:9daf61efdbff4bb1977b0bc553da113dyKyKhttp://resolver.tudelft.nl/uuid:8cea302011214b8cb9564a7fe148f4a1yKyKhttp://resolver.tudelft.nl/uuid:61c21b75bda0460ab185dac7459020f4yKyKhttp://resolver.tudelft.nl/uuid:118b4d3e2d064ce7b5a8bcc934f0468ayKyKhttp://resolver.tudelft.nl/uuid:23c338a18b3440a689e9997adbdafd75yKyKhttp://resolver.tudelft.nl/uuid:45f8e12e5d80446d9a977cac403fe1b1 yKyKhttp://resolver.tudelft.nl/uuid:dd63017ef3644107adadf5b62187812c
yKyKhttp://resolver.tudelft.nl/uuid:84f48e813aca466fac7629a65101a543yKyKhttp://resolver.tudelft.nl/uuid:e803a245b3074c018f52c3417e5d8ac7yKyKhttp://resolver.tudelft.nl/uuid:7ec081418ea94a7e923cb01d9a367b47
yKyKhttp://resolver.tudelft.nl/uuid:77460fb9b68e4d5aa0c168ba2de710e4yKyKhttp://resolver.tudelft.nl/uuid:f23d3a7699624f16be8cdab3bdfdb884yKyKhttp://resolver.tudelft.nl/uuid:adf56cdb84be4f38b8fcfad3e04acad9yKyKhttp://resolver.tudelft.nl/uuid:47632dfc4c6a48608a7bd803d5bc6395yKyKhttp://resolver.tudelft.nl/uuid:391303cb1e7141cb98e10d077668a492yKyKhttp://resolver.tudelft.nl/uuid:6a67595f598343258df9b1f628d4877fyKyKhttp://resolver.tudelft.nl/uuid:dfaae28fc2dd4bdc82d6a1c1aa98fa26yKyKhttp://resolver.tudelft.nl/uuid:cf9119d38bbf489bb734f25c4cd1402ayKyKhttp://resolver.tudelft.nl/uuid:5dcb113a162a4b49877fe3e36adb3eabyKyKhttp://resolver.tudelft.nl/uuid:3a9cc83b4e034a4ba83277f0b6eebfd1yKyKhttp://resolver.tudelft.nl/uuid:67af3eb2bc2444eebed47701e8698b4dyKyKhttp://resolver.tudelft.nl/uuid:db23e7ceee0c4cb0875503dfdc965d9byKyKhttp://resolver.tudelft.nl/uuid:0ad003efaa3746f382156f37c83af5dagg
Root Entry Fx[dx[d@SummaryInformation( F<Workbook FDocumentSummaryInformation8 F
!"#$%&'()*+,./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcdefghijklmnopqrstuvwxyz{}~