bluuebunny/crossref_metadata_2025 huggingface dataset:
Parametric Instability in Metallic Bellows Due to Internal Fluid Pressure Variation During Earthquake
Authors: Kobayashi Nobuyuki , Nagai Takanori , Watanabe Masahiro
Published: May 2009

This paper deals with the parametric instability of the metallic bellows filled with fluid and subjected to the earthquake excitation. The axial stiffness of the metallic bellows varies due to the internal fluid pressure variation, and this stiffness variation excites the parametric resonance in the metallic bellows. Finite element model about the metallic bellows that connected to the pipe is developed to examine that parametric resonance is excited in the metallic bellows by earthquake motion or not. Numerical simulations are carried out using past recorded earthquake motions. As the results, parametric resonance may be excited in the bellows when the pipe is close to resonance with the predominant frequency component of the earthquake though earthquake is not the harmonic motion.
Analysis of Granular Damping Using Hilbert Transform Based Technique
Authors: Fang X. , Luo H. , Tang J.
Published: May 2009

Granular damping results from a combination of energy dissipation mechanisms including the impact and the friction between the vibrating structure and granules and among the granules. Although simple in concept, granular damping is very complicated and its performance depends on a number of factors, such as vibration level, granular material properties, and packing ratio, etc. In this study, free vibration tests are conducted on a cantilevered beam incorporated with granular damping. A signal analysis approach based on the Hilbert transform (HT) is then employed to identify the nonlinear damping characteristics from the acquired responses, such as the dependency of the natural frequency and damping ratio on vibration level. This HT based analysis can produce an accurate temporal-frequency amplitude/energy analysis which provides us with physical insights of the nonlinear transient response. A direct comparison between the granular damping and the impact damping (with single impactor to dissipate vibratory energy) is performed to highlight the difference between these two as well as the advantages of granular damping. Finally, validity of the proposed approach is also examined by the successful prediction of vibration response using the extracted granular damping characteristics.
Modeling Nonlinear Flexible Tire Belt in the Study of In-Plane Tire Dynamics
Authors: Sugiyama Hiroyuki , Suda Yoshihiro
Published: May 2009

In this investigation, a modeling procedure for a tire with flexible belt is developed. The elastic deformation of the belt is modeled using the finite element absolute nodal coordinate formulation which allows for describing large rotational motion and the nonlinear inertia effects; the curved structure of the flexible belt; and moving boundary resulting from tread/road interaction. Using a concept of elastic ring tire models, the sidewall flexibility of tires is modeled using circumferential/radial springs and dampers between the belt and rim, while the tangential tread/road contact force is modeled using friction elements defined at contact nodes within the curved belt elements. Numerical examples are presented in order to demonstrate the use of the flexible tire model developed in this investigation. Good agreements in the tire vibration characteristics obtained using the experiments and the proposed model are demonstrated. It is also shown that the proposed tire model can be used for assessing dynamic characteristics of tires in high frequency ranges resulting from the interaction to uneven roads.
Thermal Effect of Design Parameters on the Deflection of a Disk Brake
Authors: Huang Yuan Mao , Chen Shi-Han
Published: May 2009

The deflection of a disk brake is affected by its configuration and boundary conditions. The three-dimensional finite element software ANSYS is used to analyze deflection of the disk in this study. The calculated maximum deflection occurs at the outside diameter of the disk inner board. The disk bends in the direction from the inner board toward the outer board, and the deflection coning angle of the disk is 0.4°. The calculated deflections and the coning angles of the disk are comparable with the existing data. Deflections of various disks are compared. If the thickness of the disk support region increases 1 mm, the maximum deflection decreases 0.001 mm that is about 0.2% only and it is insignificant. If the fillet radius of the support portion changes from 1 mm to 3 mm, the maximum deflection decreases 0.076 mm that it is about 15.3%. Therefore, the effect of changing the fillet radius on the deflection is more significant than that of changing the thickness of the disk support region. The mathematical model and the calculated results can be used for designing disk brakes, and a modified disk brake is recommended.
Experimental Routes to Chaos in Ball Bearings
Authors: Mevel B. , Guyader J. L.
Published: May 2009

In a previous paper [1], the theoretical prediction of a ball bearing motion was studied and different routes to chaos described. The aim of this paper is to study experimentally routes to chaos in a ball bearing and to observe whether theoretical predictions of the phenomena are realistic. An experimental test bench was built and a technique to observe Poincare´ maps is proposed. The experience clearly shows the appearance of instability in the bearing motion, and two different routes to chaos are described as expected in theory. The first route is related to the first resonant frequency of the bearing. It is a sub-harmonic route. The second route, related to the second resonant frequency, is a quasi-periodic route.
Assessing Position Order in Rigid Body Guidance: An Intuitive Approach to Fixed Pivot Selection
Authors: Myszka David H. , Murray Andrew P. , Schmiedeler James P.
Published: May 2009

This paper presents a new method for determining whether an RR dyad will pass through a set of finitely separated positions in order. Several established solution methods have been previously documented for this problem. This method utilizes only the displacement poles in the fixed frame to assess in an intuitive fashion whether a selected fixed pivot location will result in an ordered dyad solution. A line passing through the selected fixed pivot is rotated one-half revolution about the fixed pivot, in a manner similar to a propeller with infinitely long blades, to sweep the entire plane. Order is established by tracking the sequence of the displacement poles intersected by the rotating line. With four or five positions, fixed pivot locations corresponding to dyads having any specified order are readily found. Five-position problems can be directly evaluated to determine if any ordered solutions exist, and degenerate cases of four positions for which the set of fixed pivots corresponding to ordered dyads collapses to a single point on the center point curve can be identified.
Mobility and Overconstraint in Kinematic Chains and Assemblies
Authors: Rico Jose´ M. , Cervantes Sanchez J. Jesu´s , Rocha Juan , Pe´rez Gerardo I. , Tadeo Alejandro , Diez Cesar Real
Published: May 2009

This contribution presents a review of some problems concerning with the analyses of mobility and overconstraint in kinematic chains: single-loop, parallel platforms and multi-loop kinematic chains with general topology. These analyses can be easily extended to assemblies. This review shows that some ideas accepted in the literature are either incorrect or in need of clarification.
New Approaches for Better Security and Privacy in RFID Communications
Authors: Chavan Kaushik , Zeid Abe , Kamarthi Sagar
Published: May 2009

RFID is likely to emerge as a very important tool in electronically documenting the physical world to generate powerful information. In order to label millions of objects with RFID tags economically, the cost of a single tag has to be very competitive. However an inexpensive tag costing just a few cents would not have the necessary infrastructure to secure the data it stores and transmits. RFID has been drawing attention from privacy advocates and skeptics for the loopholes it can create in the information security infrastructure and consumer privacy. This article presents an overview of the security and privacy concern vis-a`-vis RFID. It surveys the research trying to ensure credible security and privacy in future low-cost RFID systems. The main purpose of this article is to hypothesize new ways of addressing concerns of security and privacy in low-cost RFID systems. Efforts are underway in the RFID Lab at Northeastern University to develop these ideas further and test their practical viability.
Vibration Confinement by Minimum Modal Energy Eigenstructure Assignment
Authors: Rastgaar Aagaah Mohammad , Ahmadian Mehdi , Southward Steve C.
Published: May 2009

A novel Eigenstructure Assignment (ESA) method for vibration confinement of flexible structures has been developed. This method is an output feedback control and determines the closed-loop systems that their eigenvectors are orthogonalized to the open-loop eigenvectors. This method is a numerical method and used Singular Value Decomposition (SVD) to find the null space of the closed-loop eigenvectors. The matrix that spans the null space can be used to regenerate the open-loop system as well as the systems that have orthogonal eigenvectors to the regenerated open-loop system. As a result the isolation of vibration is independent of the type of the disturbance. Also in this method, the energy of the closed-loop system is minimized. As an important outcome, the proposed method needs neither to specify the closed-loop eigenvalues nor to define a desired set of eigenvectors.
Design of Piezoelectric Actuator With In-Plane Motion Using Topology Optimization
Authors: Zheng Bin , Chang Ching-Jui , Gea Hae Chang
Published: May 2009

In this paper, topology optimization is used to study the design of piezoelectric actuator with in-plane motion. Two case studies are reported, the maximization of the in-plane motion toward a pre-defined direction and the maximization of the output force. In addition to volume density as design variable used in the conventional topology optimization, a new design variable, electrode density, is introduced to model the electrode topology on the piezoelectric plate surface. Based on the electrode potential model, the relation between the nodal potential and the electrode density is established. Sensitivity analyses of objective function with respect to volume density and electrode density are derived from the adjoint method. Examples of optimized piezoelectric actuators from the proposed method are presented and discussed.
Optimal Control of an Assisted Passive Snake-Like Robot Using Feedback Linearization
Authors: Mohammadi Saman , Heidari Zoya , Pendar Hojjat , Alasty Aria , Vossoughi Gholamreza
Published: May 2009

In this paper we follow two approaches in optimal nonlinear control of a snake-like robot. After deriving the dynamic equations of motion using Gibbs-Appell method, reducing these equations, and some assumptions, feedbacklinearization method was used to linearize the nonlinear system. The obtained controller is used in simulations to control robot to track a desired line, with minimum required torques. Two goals are desired. First the robot’s head is expected to track a distinct line with a given speed. And next, tracking the serpenoid curve is desired. The simulation results prove the controller efficiency. The robustness of the designed controller is shown by comparing the torques with the required torques using a PD controller. Additionally, although we had model mismatches and unmodeled dynamics in controller part, we achieved the desired goals.
Classification and Enumeration of Topological Structures of Robotic Mechanisms: Generation of Robotic Mechanisms With Unconventional Topological Structures
Authors: Arikawa Keisuke
Published: May 2009

This paper discusses the classification and enumeration of topological structures of robotic mechanisms, aiming to develop practical robotic mechanisms with unconventional topological structures. First, we consider the features of topological structures of conventional robotic mechanisms and we point out that almost all of these can be constructed by using only one simple basic unit and two simple connection rules. Then, we present an efficient way to enumerate the topological structures which cannot be constructed from the basic unit and the connection rules, or unconventional topological structures. Then, we discuss the sequence required to construct robotic mechanisms from the enumerated unconventional topological structures. In the discussion, some effective tools, “graph division”, “graph management tool” and “DOF setting based on Kuzbach criterion”, which help designers construct a variety of mechanisms from the same topological structure are introduced. Finally, some examples of the sequences allowing the generation of robotic mechanisms with unconventional topological structures are shown.
Modeling Method for Elastic Multibody Systems With Arbitary Boundary Conditions by Using Extended Reduced Order Physical Model and Its Application to a Two-Link Flexible Robot Arm
Authors: Aki Masahiko , Watanabe Toru , Seto Kazuto
Published: May 2009

This paper deals with the effectiveness of Extended Reduced Order Physical Model (EROPM) for elastic multibody systems with arbitrary boundary conditions. A novel formulation is applied to the modeling of a two-link flexible robot arm. Flexible links are modeled by using the proposed modeling method. The two-link flexible robot arm model is derived by connecting these flexible links. LQI control theory is applied for the control of the two-link flexible robot arm. The effectiveness of “EROPM with arbitrary boundary condition” is shown through simulation and experimental results.
On Constrained Systems Within Caputo Derivatives
Authors: Baleanu Dumitru
Published: May 2009

The constraints systems play a very important role in physics and engineering. The fractional variational principles were successfully applied to control problems as well as to construct the phase space of a fractional dynamical system. In this paper the fractional dynamics of discrete constrained systems is presented and the notion of the reduced phase-space is analyzed. One system possessing two primary first class constraints is analyzed in detail.
Research on Superimposed Effect of Root Stresses and Teeth Compliance Considering Multi-Teeth Meshing
Authors: Zhou Changjiang , Tang Jinyuan , Zhong Zhihua
Published: May 2009

Based on gear engagement principle, the exact curve of tooth profile is produced. By the method for compositing and modeling with MATLAB and APDL, the precise FEM model of gear is built, considering major factors of effecting root stresses and teeth compliance. Comprehensive stiffness including bending and contact stiffness is calculated during one meshing cycle. The load sharing ratio of an appointed tooth is reached, the equations of load-hist along line of action are deduced. Considering superimposed effect of engaging force in multi-teeth meshing zone, regularities of distribution of root stresses and teeth compliance in a normal meshing cycle are get. The results show that stress superimposed effect caused by adjacent meshing tooth influences compression side of the tooth is more than tension one, and makes the maximum deflection of the appointed tooth bigger. Finally, the results developed by authors show reliable, in comparison with the ones given according to authoritative methods.
Integration of PDM System and Web-Based CAE Supporting System for Small and Medium Enterprises
Authors: Bang Je-Sung , Lee Jai-Kyung , Han Seung-Ho , Park Seong-Whan , Choi Jun-Ho , Lee Tae-Hee , Kwon Tae-Woo
Published: May 2009

A web-based Computer-Aided Engineering (CAE) supporting system is integrated with a Product Data Management (PDM) system for Small and Medium Enterprises (SMEs) suffering from the lack of building hardware, software and related experts. An analysis of current business models and worksite requirements provides an improved process model and data to be shared between the PDM system and the CAE supporting system. Since all engineering tasks such as geometric modeling, mesh generation, static stress and vibration analysis, and fatigue durability analysis are automated in the CAE supporting system, the user in charge of the CAE have only to configure the concerned values of design variables and result data through the web page. The existing Change Management module of the PDM system is modified for seamless data exchange, i.e. sending the Engineering Change Order (ECO) data to the CAE supporting system and receiving the CAE result data back. The bi-directional data transfers between the PDM system and the CAE supporting system is made possible by adaptors based on the Simple Object Access Protocol (SOAP). The current approach will be very helpful for SMEs that only have the PDM system and have no adequate infrastructure for CAE.
An Analytic Model of Subminiature Auditory Sensation System for Sound Source Localization
Authors: Wang Qingsheng , Ta Na , Rao Zhushi
Published: May 2009

It is reported that some types of insects have a remarkable ability to detect the direction of an incident sound even though its acoustic sensory organs are in very close proximity to each other. The ears are maybe jointed by a cuticular structure with which the separated motions can be coupled mechanically and thus be magnified. In this paper, a detailed model is setup to describe the principle of this type of localization used a mechanical coupled structure. The transfer functions and the responses of the model in terms of time and frequency are analyzed to describe the mechanism of its ability of directional hearing. This analytical model provides a method to design the experimental model for the predetermined incident sound pressure, and the analysis of this model shows that this structure have the ability to determine the direction of the incident stimulus.
The Exploitation of Variability and Noise in Micro Devices
Authors: Nishiyama Kiyohisa , Ward M. C. L.
Published: May 2009

The strength of Micro Systems Technology (MST) is the ability to fabricate a large number of small devices economically. However such devices tend to have errors caused by the variations of fabrication and inherent noise signals such as Brownian motion or Johnson noise. This paper develops the understanding of Micro Switch Group Sensors (MSGS), which works by exploiting this random noise. In the experimental work reported here, an MSGS comprising of 20 switches has been built using electronic circuits and tested to verify the performance. The output of the device is simply the number of switches turned on, this is then transformed into the expected mean value of the input signal using standard statistical theory. The performance of the devices was shown to be in good agreement with the theoretical prediction. The linearity and the standard deviation of the output signal of MSGS are investigated and it is concluded that an MSGS may be successfully applied as a measurement tool.
Stability and Controllability Analysis of a Motorcycle
Authors: Nishimura Hidekazu , Iwamatsu Shunsuke , Zhu Shaopeng , Tajima Hiroshi
Published: May 2009

In this paper, we present a linearized system of a motorcycle and its stability and controllability analysis is done. The equation of motion for the motorcycle have been obtained using the multi-body dynamics analysis assuming that the motorcycle consists of four rigid parts with nine degrees of freedom. In this model the cross-sectional shape of the tire was described as a half circle and its deformation has been taken into account. By carrying out simulations it has been verified that the responses to the front-steering impulsive torque are in good agreement with those of a marketed dynamics analysis software. Two inputs of the steering torque and the driving torque of the rear wheel are taken into consideration. By using the balanced realization method the gramians of the linearized system are obtained to examine the reduced-order model with the frequency responses and the impulsive responses.
Experimental Investigation of Spur Gear Efficiency
Authors: Petry-Johnson T. T. , Kahraman A. , Anderson N. E. , Chase D. R.
Published: May 2009

In this study, a test methodology was developed for measurement of spur gear efficiency under high-speed and variable torque conditions. A power-circulating test machine was designed to operate at speeds to 10,000 rpm and transmitted power levels to 700 kW. A precision torque measurement system was implemented and its accuracy and repeatability in measuring torque loss in the power loop was demonstrated. Tests were conducted on gears with two values of module, and two surface roughness levels, operating in a dry sump jet-lubrication environment with three different gear lubricants. These tests were used to quantify the influence of these parameters on load-dependent (mechanical), load-independent (spin), and total power loss. Trends in mechanical gear mesh efficiency and total gearbox efficiency were discussed in terms of rotational speed and transmitted torque. Finally, recommendations were made for the design of spur gear pairs, surface roughness, and lubricant selection for improved efficiency.
Internal Gear Strains and Load Sharing in Planetary Transmissions: Model and Experiments
Authors: Singh Avinash , Kahraman Ahmet , Ligata Haris
Published: May 2009

This paper presents results of a comprehensive experimental and theoretical study to determine the influence of certain key factors in planetary transmissions on gear stresses and planetary load sharing. A series of tests are conducted on a family of planetary gear sets, and strains are recorded at various locations on the outer diameter and gear tooth fillet of the ring gear. Pinion position errors are introduced as a representative key manufacturing tolerance, and the resultant changes in the planetary behavior are observed. The experimental data is compared to the predictions of a state-of-the-art multi-body contact analysis model — ‘Gear System Analysis Modules’ (GSAM). This model is capable of including the influences of a number of system-level variables and quantifying their impact on gear strains. The model predictions are shown to compare well with the measured strain at the ring gear outer diameter and tooth fillet. GSAM predictions of planet load sharing are then used to quantify the influence of pin hole position errors on the 3, 4, 5, and 6 planet test gear sets. These predictions also agree well with the planet load sharing experiments presented in a companion paper [20].
Knowledge Composition for Efficient Analysis Problem Formulation: Part 1 — Motivation and Requirements
Authors: Bajaj Manas , Peak Russell S. , Paredis Christiaan J. J.
Published: May 2009

In simulation-based design a key challenge is to formulate and solve analysis problems efficiently to evaluate a variety of design alternatives. Numerically solving analysis problems has benefited from advancements in commercial off-the-shelf mathematical solvers and computational capabilities. However, the formulation of analysis problems for a given set of design alternatives is still typically a laborious and costly process. In the scope of design alternatives with variable topology multi-body (VTMB) characteristics, these papers (Part 1 and Part 2) present research that addresses the following primary question: How can we improve the efficiency of the analysis problem formulation process for VTMB design alternatives? The objective of this paper (Part 1) is to identify requirements for a methodology that answers this. The methodology is formulates analysis problems for VTMB design alternatives based on decisions taken by analysts and independent of the solution method (such as finite element analysis) and the solver. This paper presents a gap analysis using an example VTMB problem and identifies key inadequacies in existing approaches for analysis problem formulation. Based on the gap analysis and technical background, we present five main requirements relating to (a) key drivers for efficiently creating analysis models; (b) abstracting and formalizing analysis knowledge for composing analysis models; and (c) automatically creating, reconfiguring and verifying analysis models.
Knowledge Composition for Efficient Analysis Problem Formulation: Part 2 — Approach and Analysis Meta-Model
Authors: Bajaj Manas , Peak Russell S. , Paredis Christiaan J. J.
Published: May 2009

In Part 1 we presented technical background and a gap analysis leading to the identification of five requirements for a methodology for efficient formulation of analysis problems for VTMB design alternatives. These requirements are founded on (a) abstraction of analysis knowledge as modular, reusable, computer-interpretable, analyst-intelligible building blocks, and (b) automated creation, reconfiguration, and verification of analysis models. In this paper (Part 2), we present an example scenario to overview the Knowledge Composition Methodology (KCM) that is aimed at satisfying these requirements. The methodology is founded on analysis knowledge building blocks and a model transformation process based on graph transformations. With KCM an analyst may automatically compose an analysis model from a design model and these building blocks. In this paper, we focus on the analysis knowledge component of this methodology (illustrated for structural and thermal disciplines), and describe four dimensions of analysis knowledge. Using these dimensions, we develop a decision template for analysts to create specifications for analysis models. Analysis models can be automatically created from a given specification using model transformation techniques (not described in this paper). We leverage the notion of choices and decisions to (a) define primitive and complex building blocks of analysis knowledge, and (b) formalize an analysis meta-model that represents the structure of analysis models. We also relate this analysis meta-model to the NIST Core Product Model (CPM2). The envisioned methodology impact is a formal and systems-oriented foundational approach for analysis problem formulation that is time- and cost-effective.
An Approach Toward Estimating Cost of a New System in the Conceptual Design Stage Using Knowledge-Base
Authors: Takai Shun
Published: May 2009

To estimate profitability of a new system in the conceptual design stage, engineers need to estimate the cost of concept (the cost of the final system developed from each system concept). If engineers have abundant experiences developing similar systems, they can construct a knowledge-base consisting of historical cost data and use it to estimate the cost of concept. However, if the firm is entering a new market, engineers do not have historical cost data to accurately estimate the cost of concept. In this case, engineers need to benchmark similar systems in the marketplace and construct a knowledge-base with the benchmarked information. This paper proposes an approach toward developing a distribution (belief) about the cost of concept using a knowledge-base. The proposed approach retrieves a subset of information from the knowledge-base relevant to estimating the cost of concept, constructs a histogram about the cost of concept, and develops a distribution of the cost of concept. This paper demonstrates the proposed approach by using printers as an illustrative example.
An Approach Toward Target Warranty Costing in the Conceptual Design Stage
Authors: Takai Shun
Published: May 2009

The importance of system quality has been increasingly emphasized in the past several decades. In 1987, Malcolm Baldrige National Quality Award (MBNQA) was established to promote quality awareness. Since then, more than 1,100 organizations have applied to the award. One way to measure system quality is by warranty cost. In the automobile industry, for example, warranty costs account for 3–4% of revenue. This paper proposes a framework for managing the warranty cost by setting a target warranty cost for the system and then allocating it to system modules in the conceptual design stage. In the proposed framework, engineers begin by constructing a knowledge-base of past warranty costs. Then regression analysis is used to set the target warranty cost of the new system, and Quality Function Deployment to allocate the target warranty cost to system modules. If detailed design becomes available, engineers can then compare estimated warranty cost with the target and decide whether to further improve reliability or reduce risk of system failure. This paper demonstrates the proposed methodology by using printers as an illustrative example.
A Robotics-Based Testbed for Verifying a Systematic Method of Identifying Contact-Dynamics Model Parameters
Authors: Ma Ou , Kim Jong H.
Published: May 2009

Contact-dynamics simulations are increasingly being used in industry for enhancing product design and operation. Simulation accuracy depends not only on the simulation tools (i.e., formulation, algorithms, and computer codes) but also on the model parameters used in the simulation. Determination of contact-dynamics model parameters for a complex dynamic system is challenging. It is desirable to have a systematic method which can identify multiple model parameters directly from the physical test of the involved contact hardware. This paper describes a robotics-based experimental testbed which is specially designed for study and verification of a systematic method of identifying key parameters of multiple-point contact-dynamics models. The identification method can identify the stiffness, damping, and friction parameters all together from system-level hardware tests. The basic requirements of the testbed and how they are met by the design of the testbed are described. Some results of the preliminary test of the testbed obtained so far are also included.
Control Lie Algebras of Semi-Discretizations of the Schroedinger Equation
Authors: Kime Katherine A.
Published: May 2009

We consider control of the one-dimensional Schroedinger equation via a time-dependent rectangular potential. We discretize the equation in the space variable, obtaining a system of ODEs in which the control is bilinear. We find Control Lie Algebras for several cases, including single point and full width potentials. We use full discretizations, in space and time, to examine the effect of the number of inputs.
Influence of Pedaling Rate on Muscle Mechanical Energy in Low Power Recumbent Pedaling Using Forward Dynamic Simulations
Authors: Hakansson Nils A. , Hull Maury L.
Published: May 2009

An understanding of the muscle power contributions to the crank and limb segments in recumbent pedaling would be useful in the development of rehabilitative pedaling exercises. The objectives of this work were to (i) develop a forward dynamic model to simulate low-power pedaling in the recumbent position, (ii) use the model to quantify the power contributions of the muscles to driving the crank and limb segments, and (iii) determine whether there were differences in the muscle power contributions required to simulate recumbent pedaling at three different pedaling rates. A forward dynamic model was used to determine the individual muscle excitation amplitude and timing to drive simulations that best replicated experimental kinematics and kinetics of recumbent pedaling. The segment kinematics, pedal reaction forces, and electromyograms (EMG) of 10 muscles of the right leg were recorded from 16 subjects as they pedaled a recumbent ergometer at 40, 50, and 60 rpm and a constant 50 W workrate. Intersegmental joint moments were computed using inverse dynamics and the muscle excitation onset and offset timing were determined from the EMG data. All quantities were averaged across ten cycles for each subject and averaged across subjects. The model-generated kinematic and kinetic quantities tracked almost always within 1 SD of the experimental data for all three pedaling rates. The uniarticular hip and knee extensors generated 65 percent of the total mechanical work in recumbent pedaling. The triceps surae muscles transferred power from the limb segments to the crank and the bi-articular muscles that crossed the hip and knee delivered power to the crank during the leg transitions between flexion and extension. The functions of the individual muscles did not change with pedaling rate, but the mechanical energy generated by the knee extensors and hip flexors decreased as pedaling rate increased. By varying the pedaling rate, it is possible to manipulate the individual muscle power contributions to the crank and limb segments in recumbent pedaling and thereby design rehabilitative pedaling exercises to meet specific objectives.
Rational Motion Interpolation Under Kinematic Constraints of Planar 6R Closed Chain
Authors: Jin Zhe , Ge Q. J.
Published: May 2009

This paper deals with the problem of synthesizing planar rational motions under the kinematic constraints of planar 6R closed chain. It follows our previous work on the synthesis of rational motions under the kinematic constraints of planar open chains. Planar quaternions are used to represent planar displacements. In this way, the problem of rational motion interpolation is transformed into that of rational curve interpolation, and the kinematic constraints of a planar 6R closed chain are transformed into geometric constraints for the rational interpolation. An algorithm for the constrained motion interpolation is developed that detects an extreme position on the rational motion that violates the kinematic constraints. This position is then modified so that it is in compliance with the kinematic constraints and is added to the list of positions to be interpolated. By restricting the kinematic constraints to 5R and 4R closed chains, the algorithm is also applicable to the problem of synthesizing planar rational motions for 5R and 4R closed chains.
Active Stabilization of Repulsive Magnetic Bearing by Using Independent Motion Control of Permanent Magnets
Authors: Eirich Max , Ishino Yuji , Takasaki Masaya , Mizuno Takeshi
Published: May 2009

This paper investigates the control system design of magnetic forces using independent motion control of permanent magnets. In the permanent magnet bearing system, the radial motions of the rotor are passively supported by repulsive forces between ring-shape permanent magnets. The experimental results demonstrate that non contact levitation is achieved by independently PD controlled axial motion of permanent magnets driven by voice coil motors (VCM).
A Computational Study of Turbulent Flow and Heat Transfer Through RC/D =3.357 U-Bend Cooling Passage of Gas Turbine Blade
Authors: Guntur Krishna S. , Martinez Lucci Jose , Amano R. S.
Published: May 2009

It has been a common practice that serpentine cooling passages are used in gas turbine blade to enhance the cooling performance. Insufficient cooled blades are subject to oxidation, to cause creep rupture, and even to cause melting of the material. To control and improve temperature of blade, we have to have a better understanding of flow behavior and heat transfer inside strongly curved U-bends. The interactions between secondary flows and separation lead to very complex flow patterns. To accurately simulate these flows and heat transfer, both refined turbulence models and higher-order numerical schemes are indispensable for turbine designers to improve the cooling performance. Previous studies have shown that the flow and heat transfer features through curved bends, even with moderate curvature, cannot be accurately simulated. It is the conventional belief and practice that the usage of a proper turbulence model and a reliable numerical method for achieving accurate computations. The three-dimensional turbulent flows and heat transfer inside a sharp U-bend are numerically studied by using a non-linear low-Reynolds number (low-Re) k-ω model in which the cubic terms are included to represent the effects of extra strain-rates such as streamline curvature and three-dimensionality on both turbulence normal and shear stresses. The finite volume difference method incorporated with the higher-order bounded interpolation scheme has been employed in the present study. For the purpose of comparison, the predictions with the linear low-Reynolds number k-ω model were also performed. The success of the present prediction indicates that the model can be applied to the flow and heat transfer through a coolant passage in an actual gas turbine blade.
Resolving the Sequence-Dependent Stiffness of DNA Using Cyclization Experiments and a Computational Rod Model
Authors: Goyal Sachin , Perkins Noel C. , Meiners Jens-Christian
Published: May 2009

Structural deformations of DNA play a central role in many biological processes including gene expression. The structural deformations are sensitive to the material properties of the molecule and these, in turn, vary along the molecule’s length according to its base-pair sequence. Example ‘sequence-dependent’ material properties include the stress-free curvature and the stiffness for bending and torsion. Separating and quantifying these sequence-dependent properties from experimental data remains a significant challenge as they often work in unison in nature. In this paper, we offer a method for resolving and quantifying the sequence-dependent stiffness of DNA from cyclization (loop closure) experiments using a computational rod model of the molecule.
RFID Location Tracking System for Enhancing Police Services
Authors: Ayoade John , Anand Preetika , Rao Varunesh
Published: May 2009

The responsibility of every police officer is to protect his or her fellow citizens in times of emergency. However, it can be very difficult for police officers in headquarters to know the specific location in which their dispatched officers are when they receive an emergency call citizen. Sometimes, when the officers in headquarters receive an emergency phone call, they might not have enough officers to deploy to that particular location. Other times, some officers may be very close to a particular location, which might not be known to the officers in headquarters because of the limitation of the technologies they are using for communication. We are proposing an RFID system to help overcome this limitation. The RFID (Radio Frequency IDentification) is a technology that can be used to track an object even when it is not in the line of sight. This research work designed a ubiquitous system for the Police force to enhance the performance level of police functions. This system provides police officers in their headquarters with real time information about where their dispatched officers are located. This will help police performance and efficiency in the following ways: first and foremost, response times in attending to emergency calls will decline significantly and secondly, the resources wasted by the police force in dealing with false alarm calls will be reduced. The aim of tracking officers’ locations is to minimise the response time of police in times of emergency.
Experimental Identification of Nonlinear Continuous Vibratory Systems Using Nonlinear Principal Component Analysis: Application to Structural Modification
Authors: Kamiya Keisuke , Mizuno Yuichi
Published: May 2009

In identifying machines and structures, one sometimes encounters cases in which the system should be regarded as a nonlinear continuous system. The governing equations of motion of a nonlinear continuous system are described by a set of nonlinear partial differential equations and boundary conditions. Determining both of them simultaneously is a quite difficult task. Thus, one has to discretize the governing equations of motion, and reduce the order of the equations as much as possible. In analysis of nonlinear vibratory systems, it is known that one can reduce the order of the system by using the nonlinear normal modes while preserving the effect of the nonlinearity accurately. The nonlinear normal modes are description of motion by nonlinear functions of the coordinates for analysis. In identification it is expected that an accurate mathematical model with minimum degree of freedom can be determined if one can express the response as nonlinear functions of the coordinates for identification. Based on this idea, in a previous report the authors proposed an identification technique which uses nonlinear principal component analysis by a neural network. In this report, procedure to apply the identified result to structural modification is presented. It is shown via numerical example that when the structural modification is not so large, response prediction of the modified system with enough accuracy is possible.
Surface Reconstruction From Triple Dexel Model for Virtual Sculpting
Authors: Zhang Weihan , Leu Ming C.
Published: May 2009

This paper presents a novel method for surface reconstruction from triple dexel data for virtual sculpting. A triple dexel based virtual sculpting system is developed to provide the capability of interactive solid modeling with haptic interface. A solid model is converted to triple dexel data, which depicts the intersections of the solid with rays cast in three orthogonal directions, and modified during the virtual sculpting process. The boundary of the tool swept volume is computed based on the Sweep Differential Equation method. Contour generation and combination algorithms convert the triple dexel data to three sets of orthogonal slices of contours. A tiling algorithm then generates the solid’s boundary surface in triangular facets from these contours. Examples are given to demonstrate the ability of the developed method and software to realistically simulate the physical sculpting process and to allow viewing the sculpted models in any directions.
Procedural Design of Imprint Rolls for Fluid Pathway Fabrication
Authors: Vijayaraghavan Athulan , Dornfeld David A.
Published: May 2009

This paper discusses a novel method for designing imprint rolls for the fabrication of fluid pathways. Roller imprint processes have applications in diverse areas including fuel cell manufacturing and microfluidic device fabrication. Robust design methods are required for developing imprint rolls with optimal features. In the method discussed in this paper, the rolls are designed procedurally with the fluid pathway design given as input. The pathways are decomposed into repeating features (or tiles), and the rolls are designed by first modeling a small set of unique tiles and then combining them to model the entire roll. The tiling strategy decreases the complexity of the model, and reduces the time taken for designing the rolls. The modular nature of the tiles also improves the efficiency of post-processing operations like feature identification and optimization, and the generation of toolpaths for machining the roll.
A Fuzzy Emotion Model and Its Application in Facial Expression Recognition
Authors: Esau Natascha , Kleinjohann Lisa , Kleinjohann Bernd , Wetzel Evgenija
Published: May 2009

This paper presents a fuzzy emotion model and its use by a fuzzy emotion recognition system that allows to analyze facial expressions in video sequences. In order to process images in real-time a tracking mechanism is used for face localization. The fuzzy classification itself works on single images. It analyzes the deformation of a face using a size-invariant, feature based representation by a set of typical angles. Automatic adaptation to the characteristics of individual human faces is achieved by a short training phase that can be done before the emotion recognition starts. In contrast to most existing approaches, also blended emotions with varying intensities as proposed by many psychologists can be recognized and represented by the fuzzy emotion model. This model is generally applicable also for other emotion recognition solutions.
The Effect of Various Physical Phenomena on Wave Propagations in the Human Aorta
Authors: Mookerjee Ashis , Al-Jumaily Ahmed , Lowe Andrew
Published: May 2009

A physiologically-correct mathematical model of blood flow in the human aorta is developed from previously reported experimental data. The blood is assumed as a viscous fluid flowing through a compliant tube. This phenomenon is modeled by combining the Navier-Stokes’ equations and Laplace Law. The model is validated using experimental data collected at a leading specialist catheterisation laboratory. The mathematical model is then manipulated to derive a pressure transfer function between the aortic pressure and the pressure at the iliac bifurcation. The results of a comprehensive senstivity analysis carried out on this transfer function are discussed in this article. This study indicates that Coriolis and viscous effects insignificantly affect the wave propagation characteristics. The effect of arterial tapering on the transfer function is also recorded as insignificant. Changing the stiffness of the tube causes the pressure wave to travel faster through the system. The system natural frequency also increases when the tube wall is stiffened.
Evaluation of Tire and Suspension Characteristics With 6-DOF Motion Platform
Authors: Shiiba Taichi , Yamato Koichiro , Kobayashi Kensuke , Okada Tsuyoshi , Morita Keisuke
Published: May 2009

An accurate description of the tire characteristics is very important for vehicle dynamic analysis. However, the characteristics of a tire are very complex, and it is not easy to develop the analytical model of tire force. It is also well known that the actual tire force is greatly affected by the suspension properties. The geometry of suspension arms determines the wheel alignment specifications such as toe and camber angle, and the stiffness and damping characteristics of suspension elements influences the vertical load of each wheel. In order to investigate the suspension properties upon the tire force characteristics, the authors have developed an original tire and suspension testing machine with 6-DOF motion platform. This system is equipped with a tire, a suspension system of a passenger car, a roller conveyer, and a 6-DOF motion platform. The developed system can evaluate the relationship between the suspension system and the tire, whereas the conventional tire testing machine measures the individual characteristics of a tire. In this paper, we report some test results with developed testing system. First, the lateral force characteristics of a tire in steady-state cornering condition were evaluated with this system, and the compliance steer characteristics of a suspension caused by the lateral force were also investigated at the same time. Next, the tire force characteristics were evaluated under the varying load condition. The random vertical displacement generated by the 6-DOF motion platform was applied to the tire, and the vertical and lateral force were observed. It was shown that the developed system can realize the evaluation of tire and suspension characteristics under various conditions.
Tailoring of Two-Dimensional Band-Gap Materials for Broadband Frequency Isolation
Authors: Hussein Mahmoud I. , Hamza Karim , Hulbert Gregory M. , Saitou Kazuhiro
Published: May 2009

The spatial distribution of material phases within a periodic composite can be engineered to produce band gaps in its frequency spectrum. Applications for such composite materials include vibration and sound isolation. Previous research focused on utilizing topology optimization techniques to design two-dimensional periodic materials with a maximized band gap around a particular frequency or between two particular dispersion branches. While sizable band gaps can be realized, the possibility remains that the frequency bandwidth of the load that is to be isolated might significantly exceed the size of the band gap. In this paper, genetic algorithms are used to design squared bi-material unit cells with a maximized sum of relative band-gap widths over a prescribed frequency range of interest. The optimized unit cells therefore exhibit broadband frequency isolation characteristics. The effects of the ratios of contrasting material properties are also studied. The designed cells are subsequently used, with varying levels of material damping, to form a finite vibration isolation structure, which is subjected to broadband loading conditions. Excellent isolation properties of the synthesized material are demonstrated for this structure.