bluuebunny/crossref_metadata_2025 huggingface dataset:
A New Method for Dynamic Analysis of Pelton Runners Using CFD/FEM Interaction
Authors: Sanvito Massimiliano , Coscarelli Luisa , Pesatori Emanuel , Turozzi Giorgio , Pennacchi Paolo
Published: July 2010

The description of the dynamic behavior of a Pelton runner during normal operation is getting more and more of interest in the design of such kind of turbines. In fact, the aim to increase the performance imposes runner designs that can become critical from a structural point of view. Each bucket is subjected to a certain number of impulses per revolution corresponding to the number of nozzles. This high frequency load could lead to a great dynamic response of the runner if some kind of resonance takes place. For these reasons, a complex harmonic analysis is to be performed during the runner project, in order to avoid any crack arising during operation. This paper describes a new method to obtain the dynamic response due to the impulse load. A Pelton runner was modeled and simulated by using a FEM code (ANSYS) and a CFD (CFX) code in order to obtain its complete dynamic behavior. By using the CFD code the complete pressure profile was derived at any point of the bucket and at any time. Whilst by using the FEM code a complex harmonic analysis was computed. Combining the information of these two simulations the behavior of the stress versus time can be derived, theoretically at any point of the runner. The results of these analysis were compared with some experimental data giving a pretty good matching.
Fabrication of Eyeball-Like Spherical Micro-Lens Array for Optical Fiber Coupling
Authors: Shen S. C. , Pan C. T. , Shyu R. F. , Chao C. H. , Huang J. C. , Yeh C. Y.
Published: July 2010

Batch-fabrication of eyeball-like spherical micro-lens not only reduces micro assembly cost, but also replaces conventional ball-lenses or costly GRINs (Gradient Reflective Index) without sacrificing performance. Compared to the conventional micro-lenses made in a half-spherical geometry, the eyeball-like micro-lens is a sphere, which allows focusing light in all directions on the substrate surface, thus providing application flexibility for optical applications. The current eyeball-like spherical micro-lens is made using photoresist SU-8. This work develops a batch process at low temperature by spin-coating SU-8 on a surface of silicon wafer. The SU-8 thick film is patterned by UV lithography to form an array of holes for holding eyeball-like spherical micro-lens. The fabrication process employs bulk micromachining to fabricate an array of nozzles on the silicon wafer. Next, this process pours viscous SU-8 into the cavity of silicon wafer and presses it through the nozzle before reflow. The eyeball-like spherical micro-balls form by balancing between surface tension and cohesion. Varying the amount of SU-8 pressed through the nozzle controls the diameter of the balls. This paper designs a pattern with a 3 × 3 lens-array with a numerical aperture of about 0.38. Diameters range from 60 to 500 um. Optical measurements indicate a diameter fluctuation within 3% and an optical insertion loss is below 2.5dB with a wavelength of 635nm in a single-mode fiber (SMF). Therefore the eyeball-like spherical micro-lens is capable of increasing coupling efficiency.
Automatic Generation of UML Diagrams From Product Requirements Described by Natural Language
Authors: Chen Lei , Zeng Yong
Published: July 2010

In this paper, a novel approach is proposed to transform a requirement text described by natural language into two UML diagrams — use case and class diagrams. The transformation consists of two steps: from natural language to an intermediate graphic language called recursive object model (ROM) and from ROM to UML. The ROM diagram corresponding to a text includes the main semantic information implied in the text by modeling the relations between words in a text. Based on the semantics in the ROM diagram, a set of generation rules are proposed to generate UML diagrams from a ROM diagram. A software prototype R2U is presented as a proof of concept for this approach. A case study shows that the proposed approach is feasible. The proposed approach can be applied to requirements modeling in various engineering fields such as software engineering, automotive engineering, and aerospace engineering. The future work is pointed out at the end of this paper.
Knowledge-Based Configuration of Integrated Product and Process Platforms
Authors: Edholm P. , Wahl A. , Johannesson H. , So¨derberg R.
Published: July 2010

The definition of the content of a product platform highly affects the possibility to engineer and produce unique and optimized products to suit customer needs. In this paper, generic configurable autonomous subsystems, Configurable Components (CCs), are used to define platforms that can be used to configure and instantiate product as well as process structures and to optimize instantiated part solutions. To simulate a realistic industrial environment, a configuration demonstrator has been developed and used to perform case studies in order to test the CC concept. The test cases are focused on geometrical interfaces between components. Communication functionality between the demonstrator and a CAT (Computer Aided Tolerancing) tool has been developed to enable automatic optimization of interface concepts during configuration. In summary, the paper shows that, given variant-specific input data, a knowledge-based platform definition with high design bandwidth can be used to configure, engineer and manufacture an instanced product variant.
Three-Dimensional Kernel Development With Parasolid for Integral Sheet Metal Design With Higher Order Bifurcations
Authors: Rollmann Thomas , Schu¨le Anselm , Anderl Reiner , Chahadi Youssef
Published: July 2010

The technology of linear flow splitting to produce bifurcated sheet metal structures is researched by the collaborative research center 666 since 2005. So far the product design process is supported by 3D-CAD models on the basis of User-Defined-Features in standard 3D-CAD systems. This paper now presents a new approach for generating 3D-models of integral sheet metal design products with higher order bifurcations based on a low-level 3D-kernel. The emphasis is placed on two aspects, namely the processing of the model’s topology and geometry as well as the software implementation. First, a methodology for the generation and manipulation of the geometry and topology of the Boundary Representation (B-Rep) structure is proposed. This methodology is integrated into an algorithm-based product design approach, which enables engineers to plan and design their complete draft for bifurcated sheet metal parts in an automated, computer aided way. Further functionalities to support the subsequent manufacturing process are developed and integrated. The idea is then implemented by developing a 3D-CAD application using the B-Rep CAD-kernel Parasolid. The programming framework. NET has been chosen for the development of the software on a Windows NT platform using the object-oriented C++ and C# programming languages. The work presented here has significant implications on the quality, accurateness and efficiency of the product generation process of sheet metal products with higher order bifurcations.
An Investigations on Local and Global Behavior of a (SMA) Oscillator of 3-DOF Driven by a Limited Power Supply
Authors: Piccirillo Vini´cius , Goes Luiz Carlos Sandoval , Balthazar Jose´ Manoel
Published: July 2010

SMART material systems offer great possibilities in terms of providing novel and economical solutions to engineering problems. The technological advantages of these materials over traditional ones are due to their unique microstructure and molecular properties. Smart materials such as shape memory alloys (SMA), has been used in such diverse areas of engineering science, nowadays. In this paper, we present a numerical investigation of the dynamics interaction of a nonideal structure (NIS). We analyze the phenomenon of the passage through resonance region in the steady state processes. We remarked that this kind of problem can lead to the so-called Sommerfeld effect: steady state frequencies of the DC motor will usually increase as more power (voltage) is given to it in a step-by-step fashion. When a resonance condition with the structure it is reached, the better part of this energy it is consumed to generate large amplitude vibrations of the foundation without sensible change of the motor frequency as before. The results obtained by using numerical simulations are discussed in details.
A Cosimulation T-T Procedure Gluing Subsystems in Multibody Dynamics Simulations
Authors: Rustin Ce´dric , Verlinden Olivier , Bombled Quentin
Published: July 2010

In the case of models with numerous and eventually multidisciplinary components, cosimulation technique can be employed to link independently developed submodels. A T-T gluing algorithm is presented and validated for rigid multi-body systems. The coupling of the different submodels, resulting from exploding the all-in-one model at its mechanical joints, consists in imposing holonomic constraints for each joint separating two submodels. At each simulation step, kinematic quantities are computed and sent from the submodels to the central part of the algorithm. There a global Newton-Raphson iterative procedure permits, by means of a so-called gluing matrix, to upgrade the interface efforts which are then returned to the submodels. Two concrete examples are “cosimulated” with minimal coordinates and by considering the constraints at velocity level. The illustrated results and errors demonstrate the accuracy of the method. The algorithm can be generalized for the other kinematic approaches and for finite element and computational fluid dynamics codes.
A Modeler-Friendly API for ABM Partitioning
Authors: Gulya´s La´szlo´ , Szemes Ga´bor , Kampis George , de Back Walter
Published: July 2010

Agent Based Modeling (ABM) is a popular technique for dealing with complex systems. An ABM usually consists of many autonomous, interacting agents, and modelers are interested in the system-level, emergent behavior of these agents. In developing an ABM, scalability is one of most critical factors for validation. Looking for an acceptable solution, parallelization often comes into play. However, writing a parallel version of an ABM simulation is at least as hard as developing the original model, and usually takes an expert of the area. This paper demonstrates our ongoing developments based on the idea that ABMs can be classified on the basis of their interior communication topology. We have developed six reusable parallel simulation schemas that can be instantiated with simulation-specific code using the Java language. Our aim was to give general, domain independent support for ABM modelers, where the parallel piece of code is completely transparent. The hope is that ABM modelers can treat their parallel system in almost the same way as they do the original. The paper details our approach as well as the implementation and, towards the end, shows performance results and how one of the templates works in a GRID system.
The Development of Neural Network Cepstrum Method for Bearing Fault Detection
Authors: Hwang Yean-Ren , Jen Kuo-Kuang
Published: July 2010

A bearing diagnosis system that combines cepstrum coefficient method for feature extraction from bearing vibration signals and artificial neural network (ANN) models for the classification is proposed in this paper. We first segment the vibration signal and obtain the corresponding cepstrum coefficients, then classify the motor systems through ANN models. Utilizing the proposed method, one can identify the characteristics hiding inside the vibration signal and then diagnose the abnormalities. To evaluate this method, several experiments for the normal and abnormal conditions have been performed in the laboratory and the results are used to verify the method. It is shown that the proposed method had effectively distinguished the difference between the normal and abnormal cases and classified correctly the corresponding feature conditions.
Short Comments on an Energy Pumping Levels in a “MEMS” Gyroscope Vibrating Problem, by Using of an Global and Local Optimal Linear Control Design
Authors: Chavarette Fa´bio Roberto , Balthazar Jose´ Manoel , Rafikov Marat
Published: July 2010

This paper deals with an energy pumping that occurs in a (MEMS) Gyroscope nonlinear dynamical system, modeled with a proof mass constrained to move in a plane with two resonant modes, which are nominally orthogonal. The two modes are ideally coupled only by the rotation of the gyro about the plane’s normal vector. We also developed a linear optimal control design for reducing the oscillatory movement of the nonlinear systems to a stable point.
An Efficient Diagnosis Technique for Variations of Shaft-Bow and Unbalance
Authors: Yang Tachung , Hsu Ming-Wei
Published: July 2010

This paper focuses on the diagnosis of two types of faults, unbalance and shaft-bow, which are the common faults occurring in rotating machines. An efficient fault diagnostic method is proposed to identify the locations and amounts of faults based on the vibration responses of the rotor without prior knowledge of the numbers and locations of the faults. The proposed method achieves fast diagnosis by orderly searching the possible locations of faults, avoiding exploring all possible combinations of faults, and fully utilizing previous search results. Based on the unique search strategy, the proposed method is suitable for on-line monitoring and diagnosis of the gradual variations of shaft-bow and unbalance of large rotating machinery of fixedly rotating speeds, like steam turbine-generators of power plants.
Simultaneous Resonances of Geometric Nonlinear Nonuniform Beams
Authors: Caruntu Dumitru I.
Published: July 2010

Simultaneous resonances, superharmonic and subharmonic, of two-term excitation nonlinear bending vibrations in the case of moderately large curvature of nonuniform cantilever beams are reported. Cantilevers of constant width and parabolic thickness variation are considered in this research. The method of multiple scales is directly applied to the governing partial-differential equation of motion and boundary conditions. Two problems, zero- and first-order, result. Using factorization method, the linear modes of the zero-order problem are obtained in terms of hypergeometric functions. The first-order problem provides the amplitude-phase evolution relationship and consequently the simultaneous resonances response.
Rotating Machinery Fault Detection Using EEMD and Bispectrum
Authors: Lei Yaguo , Zuo Ming J. , Hoseini Mohammad
Published: July 2010

Ensemble empirical mode decomposition (EEMD) was developed to alleviate the mode-mixing problem in empirical mode decomposition (EMD). With EEMD, the components with physical meaning can be extracted from the signal. The bispectrum, a third-order statistic, helps identify phase-coupling effects, which are useful for detecting faults in rotating machinery. Combining the advantages of EEMD and bispectrum, this paper proposes a new method for detecting such faults. First, the original vibration signals collected from rotating machinery are decomposed by EEMD and a set of intrinsic mode functions (IMFs) is produced. Then, the IMFs are reconstructed into new signals using the weighted reconstruction algorithm developed in this paper. Finally, the reconstructed signals are analyzed via the bispectrum to detect faults. Both simulation examples and gearbox experiments demonstrate that the proposed method can detect gear faults more clearly than can directly performing bispectrum analysis on the original vibration signals.
Fluid Added Mass Effect in the Modal Response of a Pump-Turbine Impeller
Authors: Egusquiza Eduard , Valero Carme , Liang Quanwei , Coussirat Miguel , Seidel Ulrich
Published: July 2010

In this paper, the reduction in the natural frequencies of a pump-turbine impeller prototype when submerged in water has been investigated. The impeller, with a diameter of 2.870m belongs to a pump-turbine unit with a power of around 100MW. To analyze the influence of the added mass, both experimental tests and numerical simulations have been carried out. The experiment has been performed in air and in water. From the frequency response functions the modal characteristics such as natural frequencies and mode shapes have been obtained. A numerical simulation using FEM (Finite Elements Model) was done using the same boundary conditions as in the experiment (impeller in air and surrounded by a mass of water). The modal behaviour has also been calculated. The numerical results were compared with the available experimental results. The comparison shows a good agreement in the natural frequency values both in air and in water. The reduction in frequency due to the added mass effect of surrounding fluid has been calculated. The physics of this phenomenon due to the fluid structure interaction has been investigated from the analysis of the mode-shapes.
Energy Harvesting From Vibrations With a Nonlinear Oscillator
Authors: Barton David A. W. , Burrow Stephen G. , Clare Lindsay R.
Published: July 2010

In this paper we present a nonlinear electromagnetic energy harvesting device that has a broadly resonant response. The nonlinearity is generated by a particular arrangement of magnets in conjunction with an iron-cored stator. We show the resonant response of the system to both pure-tone excitation and narrow-band random excitation. In addition to the primary resonance, the super-harmonic resonances of the harvester are also investigated and we show that the corresponding mechanical up-conversion of the excitation frequency may be useful for energy harvesting. The harvester is modeled using a Duffing-type equation and the results compared to the experimental data.
Influence of Thermal Effects During Blade-Casing Contact Experiments
Authors: Millecamps Antoine , Brunel Jean-Franc¸ois , Dufre´noy Philippe , Garcin Franc¸ois , Nucci Marco
Published: July 2010

In rotating machinery, notably in modern high efficiency compressors, a critical requirement for optimal performance consists in minimizing radial clearances between the rotating bladed disk and the casing. This solution significantly increases the risks of contact between rotating bladed disk and casing and may lead in specific conditions to catastrophic behavior (component failure, etc.). The physical phenomena and mechanisms involved in blade-casing contact interaction situations are still misunderstood. In order to highlight these mechanisms, specific experiments have been performed on an experimental multi-stage compressor of a turbojet with dedicated dynamic and thermal instrumentations. For all configurations tested, major damages are noticed: blades had cracks and the abradable coating of the casing was heavily machined. Results show that the blade failure refers to fatigue limit with first natural mode excitation of the blade. The paper is focused on the analysis of the successive stages of blade dynamic response before the failure. It is shown that this response is influenced by the variations of the blade-casing contact conditions. These conditions are linked to the thermomechanical behavior and wear of coating, illustrated by high thermal levels and non uniform wear profile. Coupling between thermomechanics, wear and dynamic has to be considered to highlight the transient mechanisms leading to the cases of blade failure.
Transfer Function Modeling of Distributed Piezoelectric Vibration Energy Harvesters
Authors: Tan Chin An , Lai Heather L.
Published: July 2010

Extensive research has been conducted on vibration energy harvesting utilizing a distributed piezoelectric beam structure. A fundamental issue in the design of these harvesters is the understanding of the response of the beam to arbitrary external excitations (boundary excitations in most models). The modal analysis method has been the primary tool for evaluating the system response. However, a change in the model boundary conditions requires a reevaluation of the eigenfunctions in the series and information of higher-order dynamics may be lost in the truncation. In this paper, a frequency domain modeling approach based in the system transfer functions is proposed. The transfer function of a distributed parameter system contains all of the information required to predict the system spectrum, the system response under any initial and external disturbances, and the stability of the system response. The methodology proposed in this paper is valid for both self-adjoint and non-self-adjoint systems, and is useful for numerical computer coding and energy harvester design investigations. Examples will be discussed to demonstrate the effectiveness of this approach for designs of vibration energy harvesters.
Numerical Studies on the Frequency Response of Vibration of Damped Axially Moving Wire
Authors: Chung Chunhui , Kao Imin
Published: July 2010

The vibration response of damped axially moving wire is studied numerically in this paper for the purpose of wiresaw application. Vibration of a moving wire with damping in a slurry wiresaw system is of great interests because of its impact on the quality of the surface finish of sliced wafers and the accompanying kerf loss. The results of eigenvalues, eigenvectors, and free vibration response agree with the closed-form solution presented before. In addition, the frequency response of the system was investigated by applying point harmonic external excitation, similar to the situation with a moving wire immersed in slurry with abrasive grits. The simulation results show that the damping factor will reduce the magnitude of the response, as expected. However, the speed of the axially moving wire will shift the peak of the frequency response, which agree with the effect of apparent damping provided by the analytical solution of the system frequencies. In addition, the relationship between the nodal points of modes and the position of point excitation are also presented.
A Computational Workbench for Remote Full Field 2D Displacement and Strain Measurements
Authors: Michopoulos J. G. , Iliopoulos A. P.
Published: July 2010

The present paper reports on the progress towards the development of a computational workbench infrastructure that implements the Mesh Free Random Grid Method (MFRGM) for the remote (non contact) measurement of displacement and strain fields. The method is applicable to structures bounded by flat surfaces that deform under various mechanical and generalized loading conditions. A brief description of MFRGM is followed by the description of the current prototype of a software workbench developed for the computational implementation of the algorithms involved with the analysis display and export of the experimental results associated with any specific applications of the method. Displacement validation as well as two examples of its usage are also presented.
Modeling and Simulation of Educational Linear Motion Module
Authors: Chen Dian-sheng , Chen Yu-xin , Wang Tian-miao
Published: July 2010

In order to let the student understand the linear motion module’ principles and know how to improve the dynamic performance and control accuracy, a mathematical model is established based on the analysis of the composition and working principle of linear motion module. On the load and unload conditions, we simulate and analyze the system respectively. In the load case, PID parameters are obtained after the PID regulation. The correction of establishing the mathematical model and simulating the system are verified so that the linear motion model’ precision is effectively enhanced.
Matrix Approach to Discretization of Ordinary and Partial Differential Equations of Arbitrary Real Order: The Matlab Toolbox
Authors: Podlubny Igor , Skovranek Tomas , Vinagre Jara Blas M.
Published: July 2010

The method developed recently by Podlubny et al. (I. Podlubny, Fractional Calculus and Applied Analysis, vol. 3, no. 4, 2000, pp. 359–386; I. Podlubny et al., Journal of Computational Physics, vol. 228, no. 8, 1 May 2009, pp. 3137–3153) makes it possible to immediately obtain the discretization of ordinary and partial differential equations by replacing the derivatives with their discrete analogs in the form of triangular strip matrices. This article presents a Matlab toolbox that implements the matrix approach and allows easy and convenient discretization of ordinary and partial differential equations of arbitrary real order. The basic use of the functions implementing the matrix approach to discretization of derivatives of arbitrary real order (so-called fractional derivatives, or fractional-order derivatives), and to solution of ordinary and partial fractional differential equations, is illustrated by examples with explanations.
Quantitative Validation of Dynamic Stiffening Represented by Absolute Nodal Coordinate Formulation
Authors: Sugawara Yoshiki , Shinohara Ken , Kobayashi Nobuyuki
Published: July 2010

In recent years, various flexible structures which undergo large deformations are often applied to deployment mechanisms of space applications due to the requirements for a large structure. It is necessary to grasp their complex behaviors before the launch to escape failures as much as possible. The dynamics due to the large deformations and the overall motions are especially quite important. To overcome the difficulties of ground check about their dynamics, a powerful numerical analysis method is required strongly. In the past decade Absolute Nodal Coordinate Formulation (ANCF) method has been developed for the flexible multibody systems with large deformation and various applications have been applied to ANCF for practical use. However, there are not enough researches which validate the method by the comparison with experimental data. Especially, there are few study which conducts a quantitative validation of ANCF about overall motion with large deformation. In this paper, dynamic stiffening is focused on as one of the important overall motion. A mathematical model of two dimensional simple flexible beam is constructed based on ANCF. To simulate the dynamic stiffening by the derived model, the flexible beam is rotated horizontally in a certain angular velocity and the time history of the deformation is analyzed. Then, the results of the numerical analysis are compared with the data of corresponding experiments quantitatively.
Some Observations on Human Control of a Bicycle
Authors: Kooijman J. D. G. , Schwab A. L. , Moore Jason K.
Published: July 2010

The purpose of this study is to identify human control actions in normal bicycling. The task under study is the stabilization of the mostly unstable lateral motion of the bicycle-rider system. This is done by visual observation of the rider and measuring the vehicle motions. The observations show that very little upper-body lean occurs and that stabilization is done by steering control actions only. However, at very low forward speed a second control is introduced to the system: knee movement. Moreover, all control actions are performed at the pedaling frequency, whilst the amplitude of the steering motion increases rapidly with decreasing forward speed.
Multivariable Identification of Continuous-Time Fractional System
Authors: Thomassin Magalie , Malti Rachid
Published: July 2010

This paper presents two subspace-based methods, from the MOESP (MIMO output-error state space) family, for state-space identification of continuous-time fractional commensurate models from sampled input-output data. The methodology used in this paper involves a continuous-time fractional operator allowing to reformulate the problem so that the state-space matrices can be estimated with conventional discrete-time subspace techniques based on QR and singular value decompositions. The first method is a deterministic one whereas the second approach takes place in a stochastic context. The performance of both methods is demonstrated using Monte Carlo simulations at various signal-to-noise ratios. The deterministic method leads, as expected, to biased estimates. This bias is removed in the stochastic method by the use of an instrumental variable. As compared to rational systems, the commensurate differentiation order must be estimated besides the state-space matrices which is done using nonlinear programming. This is the first work developed for multi-input multi-output system identification using fractional models.
A Unified Optimization Design Model Under Uncertainty
Authors: Wang Zhonglai , Huang Hong-Zhong , Xu Huanwei , Zhang Xiaoling
Published: July 2010

It is necessary to combine reliability-based design and robust design in the practical engineering. In this paper, a unified framework for integrated reliability-based design and robust design is proposed. In the proposed framework, traditional multi-objective optimization problem is converted to a single objective optimization problem to integrate reliability-based design and robust design without weight factors. The conversion from probabilistic objective function to deterministic objective function is achieved by inverse reliability strategy under the consideration of the probabilistic characteristic of the objective function. After that, an improved sequential optimization and reliability assessment (SORA) method is proposed to deal with the unified framework. Overall, two examples are implemented to illustrate the benefits of the proposed methods.
Response of Electrostatically Actuated Flexible MEMS Structures to the Onset of Low-Velocity Contact
Authors: Wilcox Bryan , Dankowicz Harry , Lacarbonara Walter
Published: July 2010

Near-grazing, low-velocity contact in vibro-impacting systems has been shown to result in dramatic changes in steady-state system response following rapid transient growth of deviations away from the pre-grazing steady-state response. In low-dimensional example systems such transitions are often associated with large jumps in response amplitude. Coupled with the rapidity of the transient dynamics, this phenomenology supports the design of limit-switch sensors that trigger at the onset of grazing contact. A particularly exciting area of application of such sensors, and one in which their implementation might offer particular advantages, is in the context of microelectromechanical structures. Here, desirable scaling effects, such as increased system frequencies, low damping, batch fabrication, and decreased packaging size, can be leveraged. Fabricating simple beam structures at the microscale is relatively easier than fabricating proof-mass-based lumped-parameter systems with elaborate suspension structures. Consequently, it often becomes necessary to account for the flexibility of participating mechanical members, for example doubly-clamped, silicon-based beam elements. Physical contact further poses modeling challenges, as the flexibility of the beam elements and that of the contact region necessitate a compliant, but very stiff model description. The present work investigates a sequence of reduced-order models for such a doubly-clamped beam, subject to capacitive electrostatic actuation and a low-compliance physical constraint localized at a point along the span of the beam. The objective is to determine whether grazing-induced transitions, characteristic of lumped-mass models, are retained in the flexible structure. Specifically, numerical simulations are employed to quantify the variations in the response amplitude following the onset of contact and to contrast these to a spreading of system energy across mechanical modes.
A Survey of Health Management User Objectives Related to Diagnostic and Prognostic Metrics
Authors: Wheeler Kevin R. , Kurtoglu Tolga , Poll Scott D.
Published: July 2010

One of the most prominent technical challenges to effective deployment of health management systems is the vast difference in user objectives with respect to engineering development. In this paper, a detailed survey on the objectives of different users of health management systems is presented. These user objectives are then mapped to the metrics typically encountered in the development and testing of two main systems health management functions: diagnosis and prognosis. Using this mapping, the gaps between user goals and the metrics associated with diagnostics and prognostics are identified and presented with a collection of lessons learned from previous studies that include both industrial and military aerospace applications.
User-Oriented Simulation Models of Piezo-Bar Actuators: Part II—Integration of Nonlinearities
Authors: Boukari Abdou-Fadel , Moraru George , Carmona Jean-Claude , Malburet Francois
Published: July 2010

In [1] we proposed an approach of formalizing piezo-bar actuator dynamics models in the engineer languages. The proposed models were based on a first approximation considering that the piezo-material is linear. However, as soon as the solicitations increase one will realize that this assumption is no longer valid because non-linearities are observed. And these phenomena can seriously affect the device performances. That is why several works are conducted in order to well understand the phenomena and eventually propose means of controlling them. So, above of all we shall give in this paper an overview of existing approaches. As said in [2], all these non-linearities in piezoelectric materials are well analyzed but mostly in the framework of the fundamental physics of crystals and thermodynamics and these descriptions are extremely difficult to handle. Therefore is important to make a bridge between the fundamental studies of piezoelectric materials and classical engineering field. It is actually the purpose of this paper. We will see that due to the complexity of the phenomena and especially numerical and algebraic troubles, some simplifications could be necessary.
Service Oriented and Orchestrated Framework for Supply Chain Integration
Authors: Cheng Jack C. P. , Law Kincho H. , Jones Albert , Sriram Ram
Published: July 2010

Supply chain management integrates key business processes and facilities, involving end users and suppliers that provide products, services, and information. Supply chain integration can potentially add value to the stakeholders along product development and manufacturing life cycle as well as the customers in terms of cost, time, service level, quality, and risk. In the manufacturing industry, there are many attempts to develop methodologies, standards, and technologies to integrate various applications for product design and manufacturing. However, studies on integrating and aligning product design and manufacturing with other operations in supply chains are relatively lacking. In an integrated supply chain, information, applications, and services are shared and become available among supply chain members within and across organizational boundaries. Existing technologies and tools such as Electronic Data Interchange (EDI) infrastructures and Enterprise Resource Planning (ERP) systems do not provide a flexible and reusable solution to information sharing and application integration. This paper presents a prototype service oriented web-based system, SC Collaborator (Supply Chain Collaborator), which leverages web services, web portal, and open source technologies to provide a flexible, customizable, and economical tool for supply chain integration. The prototype system implements a service oriented portal-based framework and allows service orchestration according to processes. This paper presents the service oriented portal-based framework, the system architecture of SC Collaborator, and the schematic representation and implementation of process models with the system. The paper also illustrates the use of the SC Collaborator system to facilitate cross-functional, cross-departmental, and cross-organizational collaborations using a bus manufacturing scenario.
Accuracy of Inverse Composite Laminate Characterization via the Mesh Free Random Grid Method
Authors: Michopoulos J. G. , Iliopoulos A. P. , Furukawa T.
Published: July 2010

The present paper reports on the progress towards the evaluation of the Mesh Free Random Grid Method (MFRGM) for the inverse constitutive characterization of composite materials. The method provides the capability for the remote (non contact) measurement of displacement and strain fields of structures bounded by flat surfaces that deform under various mechanical and generalized loading conditions. The known forward solution of an anisotropic plate with an open hole, loaded at infinity, is used to generate synthetic images MFRG. The inverse problem for determining the constitutive parameters formulated directly on the generalized constitutive law. Performance of the technique is evaluated by the usage of just one frame corresponding to one set of strain state for various amounts of noise. The evaluation is repeated by utilizing frames corresponding to different rotations of the laminate relative to the loading direction. Finally the exceedingly accurate behavior of the methodology is discussed.
Sustainable Material Selection of Toxic Chemicals in Design and Manufacturing From Human Health Impact Perspective
Authors: Yuan Chris Y. , Dornfeld David A.
Published: July 2010

Toxic chemicals used in product design and manufacturing are grave concerns due to their significant impact on human health. Sustainable material selections are needed by industry to reduce the overall impact of toxic chemicals in both design and manufacturing. In this paper, we integrate the human health impact assessment into standard material selection process for developing a sustainable material selection metric for decision support in design and manufacturing. A schematic method is presented for characterizing and benchmarking the human health impact of toxic chemicals. A case study is performed on six toxic chemicals used as solvents in semiconductor manufacturing. Reliability of the schematic benchmarking results is checked and validated by comparing the results with that of conventional Human Toxicity Potential (HTP) method.
A Vehicle Motion Simulator for Testing a Mobile Surveillance Robot
Authors: Kim Sung-Soo , Kwon Jeong Joo , Park Sung ho , Park Sang Woong
Published: July 2010

A stewart platform type motion simulator[1] has been developed, in order to generate the HMMWV (High Mobility Multipurpose Wheeled Vehicle) motion. The purpose of this simulator is to test the stabilization system of the mobile surveillance robot that is mounted on the HMMWV. For developing this motion simulator, the multibody dynamics model of the motion simulator has been created using the general purpose dynamic analysis program ADAMS to validate the design of the motion simulator. Dynamics and control co-simulation model for the motion simulator has been also established for control performance analyses using ADAMS and MATLAB/Simulink. Actual hardware of the motion simulator has been fabricated. Hardware test of the motion simulator has been tried to validate the design.
Lyapunov Stability Theory for Non-Smooth Non-Autonomous Mechanical Systems Applied to the Bouncing Ball Problem
Authors: Heimsch Thomas F. , Leine Remco I.
Published: July 2010

Global attractive stability conditions for the equilibrium of the bouncing ball system have been proven in this paper using an extension of Lyapunov’s direct method to non-autonomous systems. The bouncing ball system is a non-smooth nonautonomous system with a unilateral frictionless constraint and has been extensively studied in the literature as a standard example of chaotic dynamics. The system consists of a point mass in a constant gravitational field, which bounces inelastically on a flat vibrating table. Furthermore, it is proven that the attractivity of the equilibrium is symptotic, i.e. there exists a finite time for which the solution has converged exactly to the equilibrium. For this attraction time, an upper bound is given in this paper.
Generalized GL Fractional Derivative and Its Laplace and Fourier Transform
Authors: Ortigueira Manuel D. , Trujillo Juan J.
Published: July 2010

It is well known the difficulties that the Riesz fractional derivative present, as the spatial fractional derivative involved in many models of the dynamics of anomalous processes. The generalized Gru¨nwal-Letnikov fractional derivative is analysed in this paper. Its Laplace and Fourier Transforms are computed and some current results criticized. It is shown that only the forward derivative of a sinusoid exists. This result is used to define the frequency response of a fractional linear system.
On Observability of Fractional Order Systems
Authors: Sabatier Jocelyn , Merveillaut Mathieu , Fenetau Ludovic , Oustaloup Alain
Published: July 2010

In this paper, fractional order system observability is discussed. A representation of these systems that involves a classical linear integer system and a system described by a parabolic equation is used to define the system real state and to conclude that the system state cannot be observed. However, it is also shown that the state space like representation usually encountered in the literature for fractional systems, can be used to design Luenberger like observers that permit an estimation of important variables in the system.
Design Automation of Modular Industrial Robots
Authors: Tarkian Mehdi , O¨lvander Johan , Feng Xiaolong , Petterson Marcus
Published: July 2010

This paper presents a novel approach for designing modular robots. There are two main components in this approach namely the modeling methodology of the robot and a framework for simulation of the models and execution of an optimization process. To illustrate the presented methodology an integrated analysis tool for an industrial robot is developed combining dynamic and geometric models in a parametric design approach. An optimization case is conducted to visualize the automation capabilities of the proposed framework, and enhance the design for modular industrial robots.
Development and Implementation of Shape Comparison of 3D CAD Models
Authors: Chowdhury Sagar , Siddique Zahed
Published: July 2010

With the advancements of 3D modeling software, the use of CAD in design has become a standard practice. In recent years development in computer hardware and improvements in user friendliness of the CAD software has allowed designers to quickly and easily modify the CAD models. This modification capability allows CAD to be an integral part of the design process. Due to the increase in global competition, companies have become increasingly interested in fast and efficient design processes. One way to achieve improved efficiency is through better collaboration among designers working in common or similar projects and disciplines. A large design problem often requires specialized knowledge from several fields. Collaboration among the designers from these fields will ensure efficient design. Interaction among the designers can prevent redesign of similar components/subsystems, which requires the ability to share their designs. With the increase of collaboration, designers can now get access to large databases of 3D CAD models. But the challenge lies in search capabilities to identify common models from a large database. These considerations suggest that in the near future a challenge in 3D CAD industry will be how to find models of similar components and products. This paper presents an approach and its implementation to measure the similarity among a number of CAD models. The approach is based on the extraction and organization of information from the CAD models, which is followed by the suitable selection of commonality index and calculation of the commonality among a set of CAD models. A set of Vacuum cleaners are modeled and then compared to demonstrate the application of the approach.
Close to Reality Simulation of Bulk Solids Using a Kind of 3D Cellular Automaton
Authors: Rossmann Juergen , Schluse Michael , Jung Thomas Josef , Rast Malte
Published: July 2010

The development of algorithms providing a close to reality simulation of dynamic virtual worlds made substantial technological progresses during the last decade — contrary to the close to reality simulation of bulk solids. Standard simulation methods like particle or rigid-body simulation are not applicable to this simulation problem because a large number of elements is needed for convincing simulation results which cannot be handled in real-time. In this paper we present a kind of 3-dimensional cellular automaton which can handle a large number of elements at the cost of a spatial discretization. This approach is combined with state of the art rigid body simulation techniques resulting in a close to reality simulation of bulk solids in real-time applications.
Damping Material Characterization and Modeling: An Industrial Case-Study
Authors: Poncelet Fabien , Bernay Bruno , Kerschen Gaetan , Golinval Jean-Claude
Published: July 2010

Turbojet engines contain potential nonlinearity sources such as geometric nonlinearities due to the slenderness and the length of modern blades, contacts between the blades and the shrouds, friction in the connections, and material nonlinearities. This paper focuses on the damping material which can be found in some stator stages of low-pressure compression parts. This material makes the shroud and all the blades of the stage interdependent, providing damping and fluid vein airtightness. The objective is to propose a characterization and a numerical modeling methodology that could easily be integrated within an industrial process. Nonlinearity characterization tests, based on the Restoring Force Surface method, are presented as well as viscoelastic characterization. Finally the proposed viscoelastic modeling, based on the Modal Strain Energy method, is validated against experimental data.
Instantaneous Frequency Estimation in Rotating Machinery Using a Harmonic Signal Decomposition (HARD) Parametric Method
Authors: Yiakopoulos Christos , Gryllias Konstantinos , Antoniadis Ioannis
Published: July 2010

A Harmonic Signal Decomposition (HARD) parametric method is proposed for the estimation of the instantaneous speed of rotating machinery, which makes use of vibration signals measured on a machine submitted to relative large speed variations, such as those occurring during start up or run down. The HARD method belongs typically to the class of eigenvalue based harmonic signal detection methods. The major advantage of the method over other proposed approaches is the accuracy offered by the eigenvalue decomposition methods and the computational efficiency, which may lead even to an on-line implementation of the method. The way to select the critical parameters of the method, i.e the sampling frequency and the signal length, are discussed. The performance of the method is evaluated in sinusoidal and chirp simulated signals under various noise environments, as well as to vibration measurements during the start-up and run-down of an industrial pump. As shown, the method is relatively simple to implement, has a simple computational implementation and can track efficiently the speed variations of rotating machinery.