bluuebunny/crossref_metadata_2025 huggingface dataset:
The Fractional Meta-Trigonometry Based on the R-Function: Part II—Parity Function Graphics, Laplace Transforms, Fractional Derivatives, Meta-Properties
Authors: Lorenzo Carl F.
Published: July 2010

The current fractional trigonometries and hyperboletry are based on three forms of the fractional exponential R-function, Rq,v(a,t), Rq,v(ai,t), and Rq,v(a,it). The fractional meta-trigonometry extends this to an infinite number of bases using the form Rq,v(aiα,iβt). Meta-definitions, meta-Laplace transforms, and meta-identities are developed for these generalized fractional trigonometric functions. Graphic results are presented. Extensions of the fractional trigonometries to the negative time domain and complementary fractional trigonometries are considered. Part II continues from the definition set and graphics given in Part I. It provides a minimal set of graphic results for the parity meta-fractional trigonometry and develops the meta-properties described above.
Analysis of Acoustic Wave Due to Gas Leakage in Buried Gas Pipe
Authors: Kim Eui Youl , Kim Min Soo , Lee Sang Kwon
Published: July 2010

A time frequency technique for locating leaks in buried gas distribution pipes involves the use of the cross-correlation on two measured acoustic signals on either side of a leak. This technique can be problematic for locating leaks in steel pipes, as the acoustic signals in these pipes are generally narrowband and low frequency. The effectiveness of the time-frequency technique for detecting leaks in steel pipes was investigated experimentally in an earlier study. The object of this paper is to identify the characteristics of this dispersive acoustic wave through analysis of the cut-off frequency by using the time-frequency method experimentally and BEM (boundary element method) theoretically for the development of an experimental tool to analyze the leak signals in steel pipe. The tool is based on experimental work and theoretical formulation of wave propagation in a fluid-filled pipe. This tool uses the time-frequency method to explain some of the features of wave propagation measurements made in gas pipes. Leak noise signals are generally passed through a time-frequency filter for detection of impulse signal related leakage.
Service-Oriented Architecture Based Dockside Container Crane CAD/CAE Integration System
Authors: Li Hua , Wang Chonghua , Rong Yiming
Published: July 2010

Dockside container cranes are well-known for their complex structure and thus many factors to be considered in their development. A service-oriented architecture based CAD/CAE system for dockside container crane is proposed in this paper. First, customers provide specifications of the cranes to designers through Browser/Server (B/S) based user requirement input interfaces. Second, designers parametrically model the cranes through 3D CAD platform, and CAE analysts conduct explicit dynamic Finite Element Analysis (FEA) on the designed crane structure. CAD and CAE function modules are accomplished through Client/Server (C/S) architecture. Next, based on the high-level web service and lower-level socket communication, a Design-Analysis-Integration (DAI) module is developed to maintain a model consistence between CAD module and CAE module. Then, the design results are displayed to the customers through B/S mechanism. Last, the SQL-Server based crane product database used to support the whole design and analysis processes is discussed. Since all the operations are conducted through internet/intranet and service-oriented architecture, customers, designers and analysts are able to participate in the product development processes at different geographical locations.
First-Principles-Based Modeling of Elastomeric Dampers for Multibody Systems
Authors: Bauchau Olivier A. , Ju Changkuan
Published: July 2010

Elastomeric materials have found increasing use in many vehicles, from cars and trucks to helicopters. In helicopters, the need to stabilize the very lightly damped lead-lag motions of rotor blades has necessitated the use of external dampers. Older helicopters use hydraulic dampers, which provide high levels of damping but are also associated with high maintenance costs due to the presence of seals, lubricants and numerous moving parts, all operating in a rotating frame. The motivation to reduce maintenance costs prompted the industry to switch to elastomeric lead-lag dampers that feature simpler mechanical design, lower part count, and result in “dry” rotors. This discussion clearly indicates the need for more accurate, first principle based models of elastomeric dampers. The first objective of this paper is to develop a finite element based tool for modeling the response of complex components made of elastomeric materials. Next, this tool will be integrated with a finite element based, multibody dynamics analysis code to accurately simulate the dynamic response of vehicles using elastomeric components, such as cars, trucks or rotorcraft.
A Recursive Hybrid Time-Stepping Scheme for Intermittent Contact in Multi-Rigid-Body Dynamics
Authors: Bhalerao Kishor D. , Anderson Kurt S. , Trinkle Jeffery C.
Published: July 2010

This paper describes a novel method for the modeling of intermittent contact in multi-rigid-body problems. We use a complementarity based time-stepping scheme in Featherstone’s Divide and Conquer framework to efficiently model the unilateral and bilateral constraints in the system. The time-stepping scheme relies on impulse-based equations and does not require explicit collision detection. A set of complementarity conditions is used to model the interpenetration constraint and a linearized friction cone is used to yield a linear complementarity problem. The Divide and Conquer framework ensures that the size of the resulting mixed linear complementarity problem is independent of the number of bilateral constraints in the system. This makes the proposed method especially efficient for systems where the number of bilateral constraints are much greater than the number of unilateral constraints. The method is demonstrated by applying it to a falling 3D double pendulum.
Software Archeology: A Case Study in Software Quality Assurance and Design
Authors: Turner Cameron J. , MacDonald John M. , Lloyd Jane A.
Published: July 2010

Ideally, quality is designed into software, just as quality is designed into hardware. However, when dealing with legacy systems, demonstrating that the software meets required quality standards may be difficult to achieve. Evolving customer needs, expressed by new operational requirements, resulted in the need to develop a legacy software quality assurance program at Los Alamos National Laboratory (LANL). This need led to the development of a reverse engineering approach referred to as software archaeology. This paper documents the software archaeology approaches used at LANL to demonstrate the software quality in legacy software systems. A case study for the Robotic Integrated Packaging System (RIPS) software is included to describe our approach.
A New CRONE Suspension: More Compact and More Efficient: Part 1—Problematics and Specifications
Authors: Rizzo Audrey , Moreau Xavier , Oustaloup Alain , Hernette Vincent
Published: July 2010

This paper presents, in 2 parts, a new CRONE suspension approach. The first part defines the problematics in suspension and gives the different conditions to overcome it. Then in the second paper a new CRONE suspension system is synthesized based on the conclusion of this paper. So, here, is presented how the variations of mass act on the classical suspension and how tools can be set up to simulate the influence of this variation without to choose the technological structure. Then a criterion on the level of wheel holding is established.
A New CRONE Suspension: More Compact and More Efficient: Part 2—Synthesis and Achievement
Authors: Rizzo Audrey , Moreau Xavier , Oustaloup Alain , Hernette Vincent
Published: July 2010

In a vibration isolation context, fractional derivative can be used to design suspensions which allow to obtain similar performances in spite of parameters uncertainties. This paper presents the synthesis and the achievement of a new Hydractive CRONE suspension system. After the study of the different constraint in suspension in the first paper, the ideal transfer function of the hydractive CRONE suspension is created and simulated in different case. Then a method to determine the technological parameters is proposed. A parallel arrangement of dissipative and capacitive components and a gamma arrangement are compared. They lead to the same unusual performances: the stability degree robustness and the rapidity robustness.
Towards a Function-Based Collective Innovation Framework
Authors: Messer Matthias , Grotepaß Ju¨rgen , Frenzel Ulrich K. , Panchal Jitesh H.
Published: July 2010

In this paper, we present a work-in-progress web-based framework to enable collective innovation via a combination of top-down structural and bottom-up self-organized processes in global enterprises. Problem: In current organizations, expertise is usually locked in discipline-specific project teams or departments based on existing product portfolios which restricts collective innovation through distributed networks of peers translating into increased innovation. Innovation projects are managed in stage gate processes using tools (such as proprietary project workspaces or product data management) that limit access to solutions on various levels of maturity/abstraction throughout the enterprise. Approach: Our approach to facilitate collective innovation in the early stages of product development involves identification and implementation of the following collective innovation mechanisms a) collective concept creation, b) collective concept selection, and c) collective information management. These innovation mechanisms are being instantiated in a web-enabled COllective INnovation (COIN) framework to synthesize collaborative bottom-up and structured top-down approaches fostering innovation. The COIN framework is thus based on self-organized collective innovation as well as function-based systematic conceptual design approaches thereby embodying both collaborative bottom-up and structured top-down structured aspects. From the proposed approach to collective innovation through innovation mechanisms and web enabled tools for implementing collaborative bottom-up and structured top-down structured aspects, global enterprises can benefit from the COIN-framework in fostering synergetic R&D-collaborations, know-how transfer and technology scouting during the early stages of product development. The value to global enterprises can further be significantly increased through application-tailored subspaces consisting of a collection of entities, loosely related by user-defined information links (e.g., tags), as exemplified for a sealing subspace and corkscrew design example in this paper.
Modeling the Effect of Product Architecture on Mass Collaborative Processes: An Agent-Based Approach
Authors: Le Qize , Panchal Jitesh H.
Published: July 2010

Traditional product development efforts are based on well-structured and hierarchical product development teams. The products are systematically decomposed into subsystems that are designed by dedicated teams with well-defined information flows. Recently, a new product development approach called Mass Collaborative Product Development (MCPD) has emerged. The fundamental difference between a traditional product development process and a MCPD process is that the former is based on top-down decomposition while the latter is based on evolution and self-organization. The paradigm of MCPD has resulted in highly successful products such as Wikipedia, Linux and Apache. Despite the success of various projects using MCPD, it is not well understood how the product architecture affects the evolution of products developed using such processes. To address this gap, an agent-based model to study MCPD processes is presented in this paper. Through this model, the effect of product architectures on the product evolution is studied. The model is executed for different architectures ranging from slot architecture to bus architecture and the rates of product evolution are determined. The simulation-based approach allows us to study how the degree of modularity of products affects the evolution time of products and different modules in the MCPD processes. The methodology is demonstrated using an illustrative example of mobile phones. This approach provides a simple and intuitive way to study the effects of product architecture on the MCPD processes. It is helpful in determining the best strategies for product decomposition and identifying the product architectures that are suitable for the MCPD processes.
Nonlinear Dynamics Characteristic of Rotor-Bearing System by a Finite Element Model
Authors: Li Chaofeng , Ren Zhaohui , Li Xiaopeng , Wen Bangchun
Published: July 2010

The nonlinear dynamic behavior of a rotor-bearing system is analyzed with its continuum model based on the analysis of the discrete model, with considering some other important influencing factors besides the nonlinear factors of the bearing, such as, the effect of inertia distribution and shear, transverse-torsion, structural geometric parameters of the system, which make the description of the system more embodiment and avoid the casualness of selection of system parameters. The dynamic responses of the continuum system and discrete system in the same unbalance condition are approached by the Runge-Kutta method and Newmark-β method. With the comparison of the results, significant difference about the dynamic characteristics is found with the addition of the considered factors. It is suggested that the substitution of discrete model by the continuum ones can get more accurate and abundant results. Furthermore, these results can provide more accurate verification and reference for the experiment and nonlinear dynamic design of the more complicated rotor system.
Dynamics of a Cleaning Blade Based on a 2DOF Link Model
Authors: Inagaki Yoshinori , Nohara Tsuyoshi , Kono Go , Kasama Minoru , Yoshizawa Masatsugu
Published: July 2010

To analyze the dynamics of a cleaning blade in a laser printer, observation of the vibration of the cleaning blade and analysis of a 2DOF model have been carried out. First, from the observation of the vibration of the actual cleaning blade, the stationary self-excited vibration has been confirmed. Next, a 2DOF model has been presented and its governing equations have been derived. The bottom of the model is assumed to always contact a floor surface, and the friction coefficient is constant and not dependent on the floor velocity. Third, by solving the equations governing the motion of the 2DOF model, five patterns of static equilibrium states have been obtained. Moreover it has been clarified from linear stability analysis that one of five patterns corresponds to the shape of the cleaning blade and is unstable for a small disturbance in a narrow region. This unstable vibration is a bifurcation classified as Hamiltonian-Hopf bifurcation. Fourth, by keeping up to the 3rd order terms, the nonlinear complex amplitude equation has been obtained, and the steady amplitude can be decided. As a result, the steady amplitude has been determined as the products of the 2nd order terms. Furthermore it has been clarified that such a self-excited vibration is classified as the supercritical bifurcation.
Exact Analytical Solution of Fractional Relaxation-Oscillation Equation by Adomian Decomposition and He’s Variational Technique
Authors: Basak K. C. , Ray P. C. , Bera R. K.
Published: July 2010

Exact solution of linear fractional relaxation-oscillation equation is obtained by the decomposition method of Adomian and also by He’s variational method for fractional order α, for 1 < α ≤ 2. Surface plots of the above solution are drawn for different values of fractional order α and time t. Amplitude of the oscillation increases with α but it decreases as time increases.
Coupling Methods for a Flexible Adaptive Finite Element Modeling
Authors: Barthel Corinna , Gabbert Ulrich
Published: July 2010

The qualified application of the finite element method as an important tool in the virtual engineering design process requires extensive methodological skills, competence and experience of the design engineer. There is no relevant support provided by commercial software tools. In the recent past several ideas have been proposed and tested in order to implement error controlled dimensional and model adaptivity techniques in combination with h- or p-refinement strategies. For deriving a finite element model with less degrees of freedom for time domain simulation the model adaptivity as well as the dimension adaptivity can be utilized. The application of such error controlled modeling techniques leads to finite element models consisting of domains with different local meshes and a combination of different model dimensions, such as beams, plates, shells and 3D continua. These domains have to be coupled to gain a holistic finite element model for the simulation of the local as well as the global behaviour of a system. There are different coupling methods available, each resulting in more or less additional errors, which have to be taken into account. In the paper several methods for coupling of different domains of a complex structural system are presented. They are tested with regard to their quality and their suitability in an error controlled model adaptation procedure.
Differential-Geometric Characteristics of Optimized Generalized Coordinates Partitioned Vectors for Holonomic and Non-Holonomic Multibody Systems
Authors: Terze Zdravko , Matijasˇevic´ Dubravko , Vrdoljak Milan , Koroman Vladimir
Published: July 2010

Differential-geometric characteristics and structure of optimized generalized coordinates partitioned vectors for generally constrained multibody systems are discussed. Generalized coordinates partitioning is well-known procedure that can be applied in the framework of numerical integration of DAE systems. However, although the procedure proves to be a very useful tool, it is known that an optimization algorithm for coordinates partitioning is needed to obtain the best performance. After short presentation of differential-geometric background of optimized coordinates partitioning, the structure of optimally partitioned vectors is discussed on the basis of gradient analysis of separate constraint submanifolds at configuration and velocity level when holonomic and non-holonomic constraints are present in the system. While, in the case of holonomic systems, the vectors of optimally partitioned coordinates have the same structure for generalized positions and velocities, when non-holonomic constraints are present in the system, the optimally partitioned coordinates generally differ at configuration and velocity level and separate partitioned procedure has to be applied. The conclusions of the paper are illustrated within the framework of the presented numerical example.
Damping Performance of a Particle Damper in Two Dimensions
Authors: Bhatti Riaz A. , Wang Yanrong
Published: July 2010

Particle damping is a technique of achieving high structural damping with small metallic particles embedded within a cavity that is attached to the vibrating structure at the location of high vibration amplitudes. In this work, a simple yet detailed analytical model that takes into account normal as well as oblique impacts is presented to study particle damping in two dimensions under transient vibrations. The focus of the research presented here is to determine the role of major energy dissipation mechanisms such as friction and impact phenomena involved in particle damping in context of varying two dimensional cavity sizes. Particle damping is measured experimentally for an L-shaped beam in a fixed free configuration with a cavity attached at the top free end to investigate the effect of cavity size on its performance. It is observed that the peak value of the damping is mainly influenced by the cavity size in vertical direction, but the increase in cavity size in horizontal direction, makes this peak even bigger and shifts it slightly towards lower dimensionless acceleration amplitudes values. It has been found that normal impact phenomenon remains dominant in energy dissipation but the role of impact friction becomes very important and effective in the vicinity of peak specific damping capacity value with the increase in the size of the cavity. The model predictions regarding the effect of particles to structure mass ratio on the performance of particle damper are also in agreement with the reported data in the literature.
PHM and Reflective Maintenance for the Creative Customer
Authors: Fukuda Shuichi
Published: July 2010

If we could change our maintenance to be more creative so as to satisfy our customers’ expectations, our hardware products would adapt better and work better or would be “customized better” to their own needs and to their own tastes in their present environments and situations. Then, we could create life time value for our hardware systems and could bring more profit in the long run than by trying to sell more by adding a wider variety of and higher functions to our systems in order to increasing one time value.
Robustness Analysis of the Estimators for Noisy Long-Range Dependent Time Series
Authors: Sheng Hu , Chen YangQuan
Published: July 2010

Processes with long-range correlations or called long-range dependent (LRD) processes are all around us in nature. The presence and nature of LRD is characterized by the Hurst parameter (0 < H < 1). The aim of this paper is to make a practical analysis of the robustness of the Hurst parameter estimators. A simple model of exactly self-similar process-Fractional Gaussian noise (FGN) with parameter H ∈ (0, 1) is applied to evaluate Hurst parameter estimators. The white Gaussian noise or the Symmetric α-stable (SαS) noise is superimposed in order to evaluate the reliability and the robustness of different estimators. In this paper, six statistic analysis methods, R/S statistic, Aggregated Variance method, Absolute Value method, Residuals of Regression method, Periodogram method, and Whittle method are analyzed. It follows from the comparison that the Variance of Residuals method is almost unbiased for non-noise LRD processes. And the Whittle method has best robustness to Symmetric α-stable (SαS) noisy LRD processes. The robustness analysis has practical value for analyzing noisy LRD time series, especially for the economic data, under water signal, biomedical signal and the communication signal which are corrupted by impulsive noise.
On Measures of Coupling Between the Artifact and Controller Optimal Design Problems
Authors: Peters Diane L. , Papalambros Panos Y. , Ulsoy A. Galip
Published: July 2010

Optimization of smart products requires optimizing both the artifact design and its controller. The presence of coupling between the design and control problems is an important consideration in choosing the system optimization method. Several measures of coupling have been proposed based on different viewpoints of the system. In this paper, two measures of coupling, a vector based on optimality conditions and a matrix derived from an extension of the global sensitivity equations, are shown to be related under certain conditions and to be consistent in their coupling determination. The measures’ physical interpretation and relative ease of use are discussed using the example of a positioning gantry. A further relation is derived between one measure and a modified sequential formulation that would give results sufficiently close to the true solutions.
A New Test Bench for Friction Measurements and the Evolution of the Lugre Model to the Frozen Model
Authors: Dion J. L. , Chevallier G. , Penas O. , Peyret N.
Published: July 2010

After a description of existing experimental methods and models built on the dynamic behavior of friction forces between two solids, this paper presents an original new test bench and specific measurement techniques used to better define the accuracy of measurements. This test bench has been designed for a large range of tests in terms of static strain, dynamic excitation, frequency and kinds of surfaces. The second part describes the choice of the model which is a development of the Lugre model we have called “Frozen” Model. Methods for parametric identification are proposed and comparisons between experiments and simulations are presented. In the third part a critical analysis is carried out on the test bench and its applications. (This paper is a part of a study on the prediction of vibration level of space launchers - Ariane V program). A parametrical analysis was conducted to lead and conclude a study on the robustness of the chosen model.
Nonlinear Responses of Dual Pendulum Dynamic Absorbers
Authors: Ikeda Takashi
Published: July 2010

The nonlinear responses of a single-degree-of-freedom (SDOF) system with two pendulum tuned mass dampers (TMDs) under horizontal sinusoidal excitation are investigated. In the theoretical analysis, van der Pol’s method is applied to determine the expressions for the frequency response curves. In the numerical results, the differences between single- and dual-pendulum systems are shown. Pitchfork bifurcations occur followed by mode localization where both identical pendulums vibrate but at different amplitudes. Hopf bifurcations occur and then amplitude modulated motions including chaotic vibrations appear in the identical dual-pendulum system. The Lyapunov exponents are calculated to prove the occurrence of chaotic vibrations. In a non identical dual-pendulum system, perturbed pitchfork bifurcations occur and saddle-node bifurcation points appear instead of pitchfork bifurcation points. Hopf bifurcations and amplitude modulated motions also appear. The deviation of the tuning condition is also investigated by showing the frequency response curves and bifurcation sets. The numerical simulations are shown to be in good agreement with the theoretical results. In experiments, the imperfections of the two pendulums were taken into consideration and the validity of the theoretical analysis was confirmed.
Stabilizing the Dynamics of Electrostatic MEMS Resonators Using Delayed Feedback Controller
Authors: Alsaleem Fadi M. , Younis Mohammad I.
Published: July 2010

We study the effect of delayed feedback controller on the dynamic stability of a MEMS resonator actuated with DC and AC voltages. We show that the delayed feedback controller, with a careful selection of its parameters, can be used to stabilize an originally unstable resonator operating in the escape (dynamic pull-in) frequency band. Also, the controller is shown to enhance the stability of the resonator near pull-in, where it experiences a strong fractal behavior. In both cases, the controller shows superior performance in rejecting disturbances. Experimental and theoretical results are presented to demonstrate the capability of the feedback controller to stabilize the performance of the capacitive resonator. A good agreement between simulation and experiment was achieved.
A Case Study of Mechatronic System Simulation: Forklift Electric Control
Authors: Yun D. J. , Choi J. H. , Lee S. G. , Cheng Harry
Published: July 2010

It is very difficult to simulate the realistic nonlinear dynamics model with an electrical motor with suitable control system. Recently in vehicle system design area it becomes more important for greenhouse gas emissions in the real world. This difficulties mainly exists in the time synchronize during the simulation between the mechanical field and the electrical field which should be combined into only one time integrator. This study proposes the integration approach to simulate the nonlinear system of mechanical vehicle modeling and block/script modeling for electrical control system by using an example study of forklift electric vehicle. In the interdisciplinary framework of RecurDyn and CoLink simulation environment, both tools are simultaneously analyzed in the same integrator. For demonstration of the proposed approach, fifteen degree-of-freedom multi-body model electric forklift vehicle and a Permanent Magnet Synchronous Motor (PMSM) and controllers are represented.
Analytic Sensitivity of Dynamics of Anisotropic Flexible Four-Bar Mechanisms to Stacking Sequences
Authors: Pollayi Hemaraju , Harursampath Dineshkumar
Published: July 2010

This work intends to demonstrate the importance of a geometrically nonlinear cross-sectional analysis of certain composite beam-based four-bar mechanisms by using different stacking sequences in all component bars in predicting better and critical system dynamic characteristics. In the sensitivities evaluation of the design variable considered is the layer orientation in the lay-ups of the component bars to find the optimal lay-ups which are suitable for practical applications. The goal of this optimization process is to improve the system dynamic characteristics through searching for the optimal values for the fiber orientation of all component bars in the mechanism, which relies on efficient and accurate calculation of the system sensitivities. A numerical example is presented which illustrates not only the importance of 2-D cross-sectional nonlinearities on system dynamics but also shows the advantages of selecting the well-known stacking sequence of Winckler’s system through the behavior of the system as observed by using commercial software (I-DEAS + NASTRAN + ADAMS).
Fault Diagnosis of Ball Bearings Using Soft Computing
Authors: Bhavaraju Kalyan M. , Kankar P. K. , Sharma Satish C. , Harsha S. P.
Published: July 2010

This paper presents the condition monitoring and fault diagnosis of rolling element bearings using Support Vector Machines (SVM). The vibration response of healthy bearings and bearings with various component defects such as outer race, inner race, balls and their combination have been analyzed. From the obtained vibration spectrum, it is clearly seen that a discrete peak of excitation appeared for the specific defect of bearings. In this paper, various faults of the bearings has been simulated and classified. The process includes, data acquisition, feature extraction from time response and a knowledge based system to classify faults. Features defining feature vectors are formed using statistical techniques and are fed as input to the support vector machine (SVM) classifiers. Knowledge based system developed for classification can be used for automatic recognition of machinery faults based on feature vector.
Agent-Based Micro Machining System With Cusp-Height-Minimized Tool Sequence
Authors: Wie Kyung-Hoon , Kim Hyung-Jung , Hong Young-Sun , Ahn Sung-Hoon
Published: July 2010

Agent technology can provide a systematic way to design and implement efficiently distributed intelligent manufacturing systems. Multi-agent system has been recognized as a promising paradigm to integrate a number of agents with different functions. In micro machining field many researchers have been studied the machining characteristics since the influence of underlying mechanisms are fundamentally different from macro-scale machining. This paper presents an agent-based micro machining system. To cover the process planning step for micro machining, basic agents such as cutting tool selection, tool-path generation, and machining cost estimation were implemented. To build and integrate these distributed agents, Java Agent Development Framework (JADE) was used. Throughout this system the selection of optimal roughing tool for semi-finishing stage was implemented by providing automated process planner for micro machining to the engineers. Machining data bases were constructed to store the information of materials, tools, and capability of available machine tools. A designed part can be uploaded to the Micro Machining (MM) agent as a Stereo Lithography (STL) format. MM agent can provide process parameters for 3-axis micro milling and tool sequence for cost-optimal machining automatically. Machining Cost Estimation agent can calculate micro machining cost for the designed part. To test the multi-agent system, a surface of micro-surface feature was fabricated with micro end-mills.
Energy Consistent Time Integration of Non-Conservative Hybrid Multibody Systems
Authors: Uhlar Stefan , Betsch Peter
Published: July 2010

The contribution at hand deals with the energy-consistent time integration of hybrid multibody systems. The coupling of both rigid and flexible components is facilitated by the introduction of so called coupling constraints, leading to a set of differential algebraic equations governing the motion of the hybrid system. For the modeling of rigid components we rely on the so called rotationless formulation which makes possible the design of mechanical time integrators. In this connection modeling techniques such as the coordinate augmentation, nonholonomic constraints, control issues and modeling of joint friction will be addressed. This leads to a unified approach for the modeling of rigid and flexible bodies, rendering a hybrid-energy-momentum-consistent time stepping scheme. The performance will be demonstrated with the example of a spatial nonholonomic manipulator.
A Linear Haptic Interface for the Evaluation of Shapes
Authors: Bordegoni Monica , Ferrise Francesco , Covarrubias Mario , Antolini Michele
Published: July 2010

The paper presents a haptic device that allows a user to explore a virtual object along a continuous line. In particular the device is developed with the aim of supporting designers during the evaluation of the aesthetic quality of a virtual product. This is generally done by means of the global and local analysis of the shape in terms of curvature characteristics, presence of inflections points and discontinuities. In order to evaluate such features, designers are used to work on physical prototypes, relying on their skilled sense of touch. It is known that physical prototypes are expensive in terms of cost and time for their realization, and a modification on a physical prototype implies a reverse engineering process for appling such modifications on the virtual model. A linear haptic interface, that adapts its shape reproducing a generic curve on a surface, has been developed to replicate the behavior of a physical strip. This is the way to replace real prototypes with virtual ones without changing the evaluation paradigms that designers are used to. The physical limitations encountered in representing discontinuities in position, tangency and curvature, not renderable by bending and deforming a physical strip, have been overcome thanks to the application of some principles of the theory of haptic illusions by means of sonification of some curve characteristics. The paper describes the linear haptic interface developed and the solution based on haptic illusion that has been implemented to overcome the strip limitations.
Stabilizing Periodic Orbits of Chaotic Systems Using Adaptive Critic-Based Neurofuzzy Controller
Authors: Honarvar Mohammad , Vatankhah Ramin , Salarieh Hasan , Boroushaki Mehrdad , Alasty Aria
Published: July 2010

In this paper design and evaluation of an adaptive critic-based neurofuzzy controller for the stabilizing periodic orbits of chaotic systems has been presented in detail. The main superiority of the proposed controller over previous analogous fuzzy logic controller design approaches, e.g., genetic fuzzy logic controller, is its online tuning characteristic and remarkable reduced amount of computations used for parameter adaptation, which makes it desirable for real time applications. Considering the simplicity of this controller and its independence from the system model, this control method has the advantage of online learning and control, and can be applied to a large variety of systems. The proposed adaptive scheme is used for stabilizing the 2-π and 4-π periodic orbits of a Duffing system to investigate numerically the effectiveness of the method. Also the robustness of the proposed controller was examined using input noise and parameter uncertainty in the system model. Simulation results show that the proposed algorithm can be successfully used for chaos suppression when there is not any crisp mathematical model of the dynamical system.
An Agent-Based Approach to Modeling Integrated Product Teams Undertaking a Design Activity
Authors: Sim Yee-Wai , Crowder Richard , Robinson Mark , Hughes Helen
Published: July 2010

The interactions between individual designers, within integrated product teams, and the nature of design tasks, all have a significant impact upon how well a design task can be performed, and hence the quality of the resultant product and the time in which it can be delivered. In this paper we describe an ongoing research project which aims to model integrated product teams through the use of multi-agent systems. We first describe the background and rationale for our work, and then present our initial computational model and results from the simulation of an integrated product team. The paper concludes with a discussion of how the model will evolve to improve the accuracy of the simulation.
A Condensed Modal Functional for Identifying Equivalent Constitutive Properties of an Assembled Induction Motor
Authors: Mogenier Guillaume , Baranger Thouraya Nouri , Dufour Re´gis , Durantay Lionel , Barras Nicolas
Published: July 2010

In order to predict the lateral rotordynamics of a high speed induction motor, an optimization procedure is proposed for identifying the equivalent constitutive properties especially those of the magnetic core: an assembly of lamination stack, tie rods and short-circuit rods. Modal parameters predicted by a finite element (FE) branched model based mainly on beam elements, and measured on an induction motor are included in an original energy functional. The minimization of this functional by using the Levenberg-Marquardt algorithm permits extracting the equivalent constitutive properties of the lamination stack.
Effects of Anisotropy on the Performance Sensitivity of the Mesh-Free Random Grid Method for Whole Field Strain Measurement
Authors: Iliopoulos A. P. , Michopoulos J. G.
Published: July 2010

The recently developed mesh-free random grid method (MFRGM) has been exhibiting very promising characteristics of accuracy, adaptability, implementation flexibility and efficiency. These are essential features enabling material characterization methodologies that depend on the experimental measurement of displacement and strain fields. The aim of the present paper is to present a sensitivity analysis that aids into determining the effects of the material or loading orientation of an anisotropic medium with an open hole and critical computational parameters characterizing the MFRGM in terms of its accuracy performance. First a brief outline of the MFRGM is provided. A sensitivity analysis based on the effect of the orientation angle of an anisotropic medium with an open hole is presented for a realistic choice of experimental (optical) characteristics. Finally, the effects of the mean dot size and dot distance (that are essential experimental parameters of the method) on the strain fields, are presented.
Investigating Knowledge Transfer Mechanisms for Oil Rigs
Authors: Vianello Giovanna , Ahmed Saeema
Published: July 2010

It is widely recognized, both in industry and academia, that clear strategies in knowledge transfer positively influence the success of a firm. A firm should support the transfer of knowledge by standardizing communication channels within and across departments, based upon personalization, codification or a combination of these two strategies. The characteristics of the business influence the choice of communication channels used for knowledge transfer. This paper presents a case study exploring the transfer of knowledge within and across projects, specifically the transfer of service knowledge in the case of complex machinery. The strategies used for knowledge transfer were analysed and compared with the expected transfer mechanisms, similarities and differences were investigated and are described. A family of four identical rigs for offshore drilling was the selected case. The transfer of experience across the rigs during the commissioning phase of the first and the second rigs of the series was explored through interviews with the operators and the project management team. Differences between the expected knowledge transfer strategy, focused upon the moving of rig personnel and reusing of lessons learnt from one rig to the next, and the actual situation emerged. Various approaches for transferring knowledge were elicited and analysed with regard to the types of knowledge that were transferred and the context in which they were used. This study indicates factors that should be considered whilst designing a knowledge management system to support the systematic reuse of service knowledge.
Synthesis Methods for Lightweight Lattice Structures
Authors: Graf Gregory C. , Chu Jane , Engelbrecht Sarah , Rosen David W.
Published: July 2010

Lattice structures are a type of cellular material (e.g., honeycombs, foams, trusses) that can achieve very high stiffness-to-weight and strength-to-weight ratios. When loaded, elements in lattice structures typically stretch and compress, rather than bend, enabling their advantageous performance characteristics. We desire efficient algorithms for searching the large, complex design spaces associated with lattice structure design. In this paper, we present a problem formulation for lattice structure design, using cross-section sizes as variables, and three proposed solution methods. The methods are Particle Swarm Optimization (PSO), Levenburg-Marquardt (LM) algorithm based on a least-squares minimization formulation, and a new non-iterative size matching and scaling method based on results of a finite-element analysis, which are evaluated for their capabilities in achieving light weight and high stiffness. Two-dimensional and 3-D examples are used to test the solution methods.
Possibility-Based Multidisciplinary Design Optimization in the Framework of Sequential Optimization and Reliability Assessment
Authors: Zhang Xudong , Huang Hong-Zhong , Zeng Shengkui , Wang Zhili
Published: July 2010

Reliability Based Multidisciplinary Design Optimization (RBMDO) has received increasing attention to reach high reliability and safety in complex and coupled systems. In early design of such systems, however, information is often not sufficient to construct the precise probabilistic distributions required by the RBMDO and consequently RBMDO can not be carried out effectively. The present work proposes a method of Possibility Based Multidisciplinary Design Optimization (PBMDO) within the framework of the Sequential Optimization and Reliability Assessment (PBMDO-SORA). The proposed method enables designers to solve MDO problems without sufficient information on the uncertainties associated with variables, and also to efficiently decrease the computational demand. The efficiency of the proposed method is illustrated with an engineering design.
Features of Early Cracks in a Gear Based on a 16DOF Nonlinear Time-Varying Stiffness Dynamic Model
Authors: Zhou Xiaojun , Shao Yimin , Zuo Ming J.
Published: July 2010

A 16DOF nonlinear time-varying stiffness dynamic model of a one-stage spur gear system is studied when there is a crack growth on the pinion; the energy method is then used for calculating the meshing stiffness of the gear pairs. A Hybrid Digital Filter is used to detect the feature signal which is induced by the tooth crack when the vibration signal contains heavy noise. The relationship between the indicators and the growth of the crack is given.
Fuzzy Reliability Prediction Method Based on FMECA for Diesel Engine
Authors: Zhang Han-Liang , Huang Hong-Zhong , Liu Yu
Published: July 2010

Diesel engine is a multi-disciplinary complex system with the harsh working environment and high reliability requirements. Its design for satisfying the basic reliability requirement is a high-demanding work. Correspondingly the reliability prediction is served as an important tool for reliability design. However, in the traditional reliability method, the analytical outcome obtained from the conventional FMECA was not always sufficient. This increases the workload of designers in charge of reliability, and reduces the working efficiency. Therefore, this paper conducts an in-depth research with the emphasis on the diesel engine’s reliability prediction, in which the failure mode and the information of criticality provided by FMECA will be made full use of to carry out the reliability prediction. Meanwhile, to make the prediction results more objective and reasonable, this paper introduces the weight of experts, and provides a prediction model, in which the fuzzy analytic hierarchy process and the fuzzy comprehensive evaluation are combined to analyze the criticality of FMECA.
Control-Based Continuation of Unstable Periodic Orbits
Authors: Sieber Jan , Krauskopf Bernd , Wagg David , Neild Simon , Gonzalez-Buelga Alicia
Published: July 2010

We present an experimental procedure to track periodic orbits through a fold (saddle-node) bifurcation, and demonstrate it with a parametrically excited pendulum experiment where the control parameter is the amplitude of the excitation. Specifically, we track the initially stable period-one rotation of the pendulum through its fold bifurcation and along the unstable branch. The fold bifurcation itself corresponds physically to the minimal amplitude that is able to support sustained rotation. Our scheme is based on a modification of time-delayed feedback in a continuation setting, and we show for an idealized model that it converges with the same efficiency as classical proportional-plus-derivative control.
ANN Based Fault Classification of High Speed Ball Bearings
Authors: Bhatnagar Aashish , Kankar P. K. , Sharma Satish C. , Harsha S. P.
Published: July 2010

In the rotating machines, maintenance of the high speed operated bearings is the major problem and is one of the key issues due to excessive vibrations. Hence, the vibration signatures can be used as a feature for the fault diagnosis. This paper presents the Artificial Neural Networks (ANN) based fault analysis, which is used to classify various known faults using the features extracted from the vibration signals. The vibration signals from the piezoelectric accelerometers are being measured for the following conditions — No defect (NOD), Outer race defect (ORD), Inner race defect (IRD), Ball fault (BF) and Combination of above (COMB). The features are extracted from the time domain using the statistical method. These features are filtered using wavelet filter & kernel filter and compiled as the input vectors. The multilayer neural network is trained by these input vectors. The training and testing results show that wavelet and kernel filter can be effective tool in the diagnosis of ball bearing faults using ANN. Results obtained from the ANN predict that the wavelet filter provides good accuracy with reduction in the training time.
Denavit-Hartenberg Parameters of Euler-Angle-Joints for Order (N) Recursive Forward Dynamics
Authors: Shah Suril , Saha Subir Kumar , Dutt Jatyanta Kumar
Published: July 2010

Euler angles are generally used for representing rigid body rotation in three dimensions. In this paper we introduce a concept of Euler-angle-joints (EAJs) which are nothing but three revolute joints so connected by imaginary links with zero length to represent particular Euler angle set. These EAJs can be represented using the well-known Denavit-Hartenberg (DH) parameters. The proposed EAJs are useful in representing a spherical joint present in any multibody system. One can then derive a corresponding decoupled natural orthogonal complement (DeNOC) matrices used in dynamic formulation to obtain the analytical expressions of the generalized inertia matrix elements in scalar form. These expressions are used to develop an O(n) — n being the number of degree-of-freedom of a serial chain — recursive forward dynamics algorithm. The methodology suggested is illustrated with a numerical example.