bluuebunny/crossref_metadata_2025_split huggingface dataset:
Vibration Control With Neural Network Dynamic Compensator
Authors: Shiotsuka Toshinari , Yoshida Kazuo , Nagamatsu Akio 
Published: March 2021

Abstract
An approach is presented on designing the dynamic compensator-type controller, using two kinds of neural networks. One is used for identification of system dynamic characteristics of the control object. A time history of response under sine-sweep input is used as the teaching signal of this neural network.
The other is used as the neural network controller. The control input is determined with this neural network in order that a performance index concerning the state variable and the input force takes the minimum value.
These two neural networks are combined reciprocally in a cascade type in designing the controller. Validity and usefulness of the presented approach are verified by both an computer simulation and an experiment with an active suspension model.
Nonstationary Robust Positioning Control of Flexible Structures
Authors: Hara Susumu , Yoshida Kazuo 
Published: March 2021

Abstract
For positioning control of such vibrating system as flexible structures, it is important to reduce vibration. In the problem, influences of such uncertainties as variations of parameters of controllers possess nonstationary characteristics. This paper presents an integrated synthesis method of both motion and vibration controller maintaining the robustness of the control by using a time-varying criterion function. In this method, a smooth change from H2 positioning control to H vibration control is realized by solving time-varying Riccati equations in stead of time-invariant Riccati equations. This method is applied to a positioning problem of flexible tower-like structure. In comparison with the former methods proposed by the authors, the usefulness of the method is verified theoretically and experimentally.
An Optimal Design Method for Rubber Dynamic Vibration Absorber
Authors: Satoh Yoshihiro , Misawa Hiroshi 
Published: March 2021

Abstract
A dynamic vibration absorber can be used for suppression of excessive amplitude of structures at the resonance. This paper deals with an optimal design method for the dynamic vibration absorber which consists of a mass and a carbon-black filled rubber vulcanizate. First, a system which consists of a main system and the dynamic vibration absorber was analyzed, considering nonlinear dynamic properties possessed by the rubber vulcanizate. Frequency response functions of the system were derived in the form including the rubber geometry and a mass ratio as design parameters. Next, an objective function was composed of the frequency response functions. Minimizing the objective function with respect to the parameters of the rubber geometry for given mass ratio, the optimal values were determined. From the consideration of the results, a new convenient method to determine the optimal values was derived. This method was examined by the experiments. As a result, the validity of the analysis method was verified, and the availability of the present design method for the suppression of vibration was confirmed.
Contact Impedance Sensors: Applicability for the Evaluation of Flexible Structures
Authors: Daugela Antanas , Fujii Hiroshi , Misaki Akitsugu 
Published: March 2021

Abstract
The Mechanical Contact Impedance Evaluation (MCIE) method has not been throughly explored in order to test elastic polymers. In this paper the applicability of MCIE for defining the mechanical properties of elastic materials and structures is discussed in detail. The analytical solution of the resonance state equation shows that the MCIE method is effective in the case of piezo active flexural vibrators which excite the surface of the specimen in the normal direction. The results received from the FEM modal and harmonic analysis, where longitudinal, flexural and torsion vibrators were simulated, support the conclusion above. Experimental results received from the analysis of flexural vibrator show that the MCIE can be successfully used in a comparator to evaluate elastic polymers when quick and nondestructive testing is required.
Sensorless Active Suppression of Transverse Vibration of Flexible Plate
Authors: Matsuda Ken-ichi , Okada Yohji 
Published: March 2021

Abstract
In rolling processes, flexible steel sheet is supported by rollers and is bound to produce structural vibration. This vibration can cause severe problem to surface finish and affect the quality of the product. To overcome this problem, active vibration control has been proposed. This usually requires both sensors and actuators. The location of sensors and actuators play a very important role in active vibration control. Moreover, a reliable sensor can be very expensive. This paper proposes a self-sensing vibration control using a push-pull type electromagnet to control the transverse vibration of the steel plate. The construction of the electromagnet has two types of coils, namely the bias coil and the control coil. Vibration displacement is estimated by using the mutual inductance change between the bias and the control coils. The estimated signal is proportional to the gap displacement. The proportional and derivative signal of which is fedback to the control coil to control the transverse vibration of the steel sheet. The proposed method is applied to a simple test rig to confirm the capability of the device. The results obtained are showing high possibility for reducing the sheet steel vibration.
Active and Regenerative Control of Electrodynamic Vibration Damper
Authors: Okada Yohji , Harada Hideyuki 
Published: March 2021

Abstract
A new method of regenerating electric power from the vibration energy is presented. An electro-dynamic actuator is controlled by a relay controller to regenerate electric power during the highspeed motion of the actuator. For the lowspeed motion, an active control algorithm is applied to the same actuator to achieve good damping performance. This idea can be applied to a vehicle suspension system which is composed of electrodynamic actuator and spring. The system is simulated on a computer to evaluate the vibration damping property and energy regenerative capability. A simple experimental apparatus is made to confirm its capability.
Response of Piezoelectric Solids to Unitary Impulsive Loads: A Computational Approach
Authors: Khutoryansky Naum , Sosa Horacio 
Published: March 2021

Abstract
Fundamental solutions for transient dynamic piezo-electricity are derived through the plane wave decomposition and represented in three alternative manners, namely over the unit sphere, over the material’s slowness surface and over a line of the latter. The computational virtues of the uni-dimensional integral representation are exposed through a numerical example concerning a transversely isotropic piezoelectric ceramic subjected to unitary impulsive applied forces.
Piezoelectric Actuation of von Karman Circular Plates With Thermal Deformation and Nonlinear Oscillation
Authors: Tzou H. S. , Zhou Y.-H. 
Published: March 2021

Abstract
Linear dynamics and distributed control of piezoelectric laminated continua have been intensively studied in recent years. In this study, dynamics, electromechanical couplings, and control of thermal buckling of a piezoelectric laminated circular plate with an initial nonlinear large deformation are investigated. It is assumed that the von Karman type geometrically nonlinear deformation is considered. In addition, the piezoelectric layers are uniformly distributed on the top and bottom surfaces of the circular plate. Accordingly, control effect is introduced via an equivalent control moment on the circumference. Dynamic equations and boundary conditions including elastic and piezoelectric couplings are formulated, and solutions are derived. Active control of plate’s nonlinear deflections, thermal buckling, and natural frequencies using high control voltages are studied, and their nonlinear effects are evaluated.
Simultaneous Use of Piezoelectric Ceramics As Sensor and Actuator for Through-Plate Sound Transmission Control
Authors: Akishita Sadao , Aoyama Satoru , Yokoi Kenji , Ma Chris C. H. 
Published: March 2021

Abstract
Externally applied electric field in piezoelectric material causes mechanical stress in addition to electric charge displacement. This effect is bidirectional in that mechanical strain can in turn cause electric charge displacement. The bidirectionality suggests that a piezoelectric element can be used simultaneously as both a sensor and an actuator for bending vibration control of a thin plate. To do this, the key problem that needs to be solved is to separate the two kinds of electric charge displacement generated in the piezoeoectric element due to the mechanical strain and the electric control signal. By introducing a dummy piezo-electric element to provide a reference on the effect due to the electric control signal only, successful separation of the two kinds of charge displacement signals has been accomplished. The effectiveness of the simultaneous use for the control system is demonstrated in substantial reductions of the sound pressure transmitted and the bending vibration in the plate.
Identification of a Significantly Non-Proportionally Damped Structure Using Force Appropriation
Authors: Holmes P. S. , Wright J. R. , Cooper J. E. 
Published: March 2021

Abstract
Dynamic tests were carried out on an aluminium plate with significant non-proportional damping applied via two oil filled dampers. Normal mode force appropriation (phase resonance) methods were used to measure the undamped normal modes of the plate and the results compared with corresponding complex modes obtained using a standard curve fitting (phase separation) approach.
It is demonstrated that, as long as suitable excitation positions are chosen, high quality undamped normal modes can be identified while the curve fitted modes are highly complex. A Finite Element analysis of the plate was used to show how the results of normal mode force appropriation are directly comparable, particularly when damping is non-proportional.
The Frequencies and Damping of a Cantilever Composite Plate With a Viscoelastic Layer
Authors: Cupiał P. , Nizioł J. 
Published: March 2021

Abstract
In the paper the natural frequencies and modal loss factors of a three-layered rectangular cantilever plate with high-modulus composite face layers and a viscoelastic mid-layer are discussed. Two analysis approaches are considered, the Ritz method and the finite element method. The Ritz analysis is based on an appropriate 2-D plate model. Algebraic polynomials are used which satisfy the necessary geometric boundary conditions. The discretized eigenvalue problem is then solved for complex eigenvalues, from which damped frequencies and modal loss factors are extracted. Both frequencies and loss factors are shown to converge with an increasing number of the polynomials used. Apart from the Ritz method, frequencies and modal loss factors are calculated by the finite element method based on the so-called strain energy method. Comparison between the two approaches is then given.
The Method of Trajectories for Finding Eigenfrequencies of Damped Structures
Authors: Pesterev Alexander V. , Tavrizov Grigorii A. 
Published: March 2021

Abstract
The method of finding complex eigenfrequencies of distributed parameter structures with finite number of lumped dampers is presented. The approach used is based upon the structural analysis method in the context of which the problem of investigation of a system degenerates into investigation of some complex characteristic matrix. Multiplication of all damping coefficients by a real scalar parameter α results in consideration of a family of α-parametrized intermediate systems. When α varies eigenfrequencies of the intermediate systems describe trajectories in the complex plane. The differential equation governing the trajectories is established. Given the eigenfrequencies of the conservative system those of the damped structure can be obtained by integrating the differential equation.
Transient and Steady-State Response of Constrained Translating Strings
Authors: Zhu W. D. , Mote C. D. 
Published: March 2021

Abstract
The exact expression describing the constraint force in a constrained translating string is derived using the Green’s function formulation. Discontinuity of the initial velocity at a boundary of the string due to a disturbance causes discontinuity in the constraint force history for any constraint that is not modeled by a single spring element. The discontinuities in the constraint force occur at instants when those propagating wave-fronts in the string with non-vanishing slope interact with the constraint. A model of a magnetic tape-recording head system is analyzed. Tape-head contact loss is predicted, depending on the amplitude and frequency of the disturbance, the head location and the preload of the tape against the head. The transient response to a harmonic end excitation is compared at the steady state to the closed-form prediction of a steady forced analysis.
Applications of Electrical Impedance Tomography to Nondestructive Evaluation
Authors: Santosa Fadil 
Published: March 2021

Abstract
Electrical impedance tomography is a technique for imaging the interior of a region using DC current and voltage measurements collected on the boundary of the region. The image obtained corresponds to the conductivity of the material in the region. This tomographic method has its origins in geophysical exploration and in biomedical imaging.
In this paper, we describe two applications of this technique for NDE. In the first application, we devise a method for determining the length and the location of a straight-line crack in a circular domain. The second application concerns the use of electrical impedance tomography for imaging corrosion in plates.
Stability and Resolution in Thermal Imaging
Authors: Bryan Kurt , Caudill Lester F. 
Published: March 2021

Abstract
This paper examines an inverse problem which arises in thermal imaging. We investigate the problem of detecting and imaging corrosion in a material sample by applying a heat flux and measuring the induced temperature on the sample’s exterior boundary. The goal is to identify the profile of some inaccessible portion of the boundary. We study the case in which one has data at every point on the boundary of the region, as well as the case in which only finitely many measurements are available. An inversion procedure is developed and used to study the stability of the inverse problem for various experimental configurations.
Estimating the Interaction Kernel in a Mathematical Model for a Beam With Internal Damping Mechanism
Authors: Lin Tao , Russell David L. 
Published: March 2021

Abstract
Beams formed by long fiber composite materials have certain internal damping torque. A mathematical model for the displacement of this type of beams in cantilever configuration is the following initial-boundary value problem of an integro-differential equation [1, 14]:
(1) ρ ( x ) w t t ( x , t ) − 2 ( ∫ 0 L h ( x , y ) [ w t x ( x , t ) − w t x ( y , t ) ] d y ) x + ( E I w x x ( x , t ) ) x x = f ( x , t ) ,
(2) w ( 0 , t ) = 0 , w x ( 0 , t ) = 0 ,
(3) w x x ( L , t ) = b l 1 ( t ) ,
(4) − ( E I w x x ( x , t ) ) x | x = L + 2 ∫ 0 L h ( L , y ) [ w t x ( L , t ) − w t x ( y , t ) ] d y = b l 2 ( t ) ,
(5) w ( x , 0 ) = w 0 ( x ) , w t ( x , 0 ) = w 1 ( x ) ,
where L is length of the beam, w(x, t) is the transverse displacement of the beam at time t and position x, ρ(x) is the mass density, EI is the stiffness parameter. The interaction integral kernel h(x, ξ) is introduced in this model by considering a restoring torque which comes from spatially variable bending of the beam. This kernel h(x, ξ) depends on the material properties of the beam. Choosing a different material (different h(x, ξ)) can realize a different damping effect for the beam.
Identification of Vehicle-Bridge Interactive Forces From Measured Bridge Responses: Theoretical Studies
Authors: Law S. S. , Chan Tommy H. T. , Zeng Q. H. 
Published: March 2021

Abstract
Information of the vehicle-bridge interaction force is an important parameter in the design and evaluation of highway bridges. However it is difficult to directly measure or accurately calculate the force which is a moving force. The objective of this paper is to explore the theory of force identification based on the response of the structure to acquire a time history of the moving force. The force will be identified in time domain using a modal superposition method. A moving force on a simply supported beam is simulated, and the computational results show that the method is noise sensitive, and yet acceptable results can be obtained by combining the use of vibration data of the bending moment and acceleration measurements.
Model Verification and Validation in Engineering: Updating of Mathematical Models by the Use of Test Data
Authors: Natke H. Günther 
Published: March 2021

Abstract
Mathematical models are uncertain. Therefore they have to be verified and validated in order to obtain usable models.
Models are maps of systems. Thus, one first has to define the expressions, and secondly, one has to give the relations between them.
The best available information about the system stems from the existing system: measurements. Consequently, system identification methods are used for model verification and validation.
The uncertainties of the prior model and of the measurements have to be modelled. This is done probabilistically. The resulting updating methods are discussed, including the problems arising, and procedures for overcoming them.
Parameterisation of Joints and Constraints for Finite Element Model Updating
Authors: Friswell Michael I. , Mottershead John E. , Ng Gary H. T. , Smart Mark G. 
Published: March 2021

Abstract
The sensitivity method is applied to update finite element models of welded and bolted joints, and the boundary condition of a cantilever plate. Careful parameterisation is found to be critical in updating the joints and boundary conditions. Updating geometric parameters has considerable potential in updating. The use of nodal offset dimensions results in an updated model of the welded joint with physical interpretation. Similarly the ‘rigid’ boundary in a cantilever plate is successfully updated using the effective length of the elements closest to the joint. In all cases an improvement on the analytical natural frequencies is demonstrated.
Structural Fault Localization Using Direct Stiffness Update Methods
Authors: Verçosa Carlson Antonio M. , Arruda José Roberto F. 
Published: March 2021

Abstract
The problems caused by experimental data incompleteness when using optimal-matrix update methods are well known. Since the advent of laser-based vibration measurements, the number of measured degrees-of-freedom may be very large, even larger than the number of degrees-of-freedom in a finite element model. Considering that the incompleteness problem may now be partly solved, this paper revisits some well-established direct stiffness update methods, as well as a method recently proposed by the authors, for use in structural fault localization applications. The methods are appraised using a simulation example consisting of a clamped-free beam. The force cancellation between adjacent finite elements, which is known to create an impossible situation for Kabe’s method, is solved by introducing the concept of pseudo sparsity. The effects of modal truncation, expansion, and additive noise are investigated.
Updating a Non-Conservative Finite Element Model: Two Modal Methods
Authors: Moine Pascal , Billet Laurent , Aubry Denis 
Published: March 2021

Abstract
Two updating methods using modal data are proposed to update damped F.E. models. The first one is based on a sensitivity approach whereas the second one minimises some energy error. It is possible to derive from the second method a density error function which allows to localise erroneous structural parameters. Numerical tests are presented in order to evaluate the performances of the two methods.
Error Localization Methods With Static Modes and Thermographic Data
Authors: Thouverez F. , Humbert L. , Jezequel L. 
Published: March 2021

Abstract
The goal of updating methods in dynamic is to improve the finite element models by means of experimental tests. In fact, we try to estimate a better value of the mass (M) and stiffness (K) matrices. Several ways are possible to complete the updating of M and K :
- Global techniques which consist to correct the entire matrices without keeping a physical meaning of the M and K modifications. This approach transforms the finite element “knowledge” models into “representation” models which are more accurate in the measured frequency range but don’t represent the actual structure. This kind of method has been developed first by Baruch (1978) and Berman (1979) and improved by lots of researchers (Kabe, 1985 and Wei, 1990).
- Local techniques try to compute the best values of the physical parameters defined on each element of the modelling. This method is a very stiff one since the optimization of the numerical modes is required over a very large number of parameters. To be able to use this approach we must select only the elements which must be modified to reduce the size of the optimization problem. To do so, we will apply the localization methods. In this paper we will present two ways to locate the modelling errors as well as a new approach based on thermographic, data. Each localization methods will be tested and we will show the influence of the expansion technique and the improvement due to the use of the static modes. The thermographic measurements give us a large number of data but partial because the information gathered by the camera concernes only the sum of the principal strains (Olivier et al, 1988 and Ryall et al, 1992). But the advantages of this method are the number of points which is important and the nature of the data which is a strain information (very sensitive to the local defaults of modelling).
The Laser Torsional Vibrometer: Successful Operation During Lateral Vibrations
Authors: Miles Toby J. , Lucas Margaret , Rothberg Steven J. 
Published: March 2021

Abstract
Torsional vibration of rotating shafts can contribute significantly to machinery noise and vibration levels. The Laser Torsional Vibrometer has been developed for accurate non-contact measurement of the torsional oscillation of rotating components, with advantages over conventional techniques. Its optical geometry offers inherent immunity to lateral shaft vibration in most cases but the instrument is sensitive to specific types of lateral shaft vibration under certain circumstances. Theory is presented to illustrate this effect on the Vibrometer measurements and close agreement with experimental results is found. The significance of this cross-sensitivity is discussed and illustrated with experimental results from two different engine applications, allowing the specification of optimum configurations to ensure effective immunity to all lateral vibration.