bluuebunny/crossref_metadata_2025 huggingface dataset:
Interval Reliability Analysis
Authors: Du Xiaoping
Published: May 2009

Traditional reliability analysis uses probability distributions to calculate reliability. In many engineering applications, some nondeterministic variables are known within intervals. When both random variables and interval variables are present, a single probability measure, namely, the probability of failure or reliability, is not available in general; but its lower and upper bounds exist. The mixture of distributions and intervals makes reliability analysis more difficult. Our goal is to investigate computational tools to quantify the effects of random and interval inputs on reliability associated with performance characteristics. The proposed reliability analysis framework consists of two components — direct reliability analysis and inverse reliability analysis. The algorithms are based on the First Order Reliability Method and many existing reliability analysis methods. The efficient and robust improved HL-RF method is further developed to accommodate interval variables. To deal with interval variables for black-box functions, nonlinear optimization is used to identify the extreme values of a performance characteristic. The direct reliability analysis provides bounds of a probability of failure; the inverse reliability analysis computes the bounds of the percentile value of a performance characteristic given reliability. One engineering example is provided.
Cable-Suspended Vehicle Simulation System Concept
Authors: Williams Robert L.
Published: May 2009

This paper presents a concept for virtual-reality-based vehicle simulation with whole-body haptics. The cable-suspended NIST RoboCrane is adapted to carry human operators in simulating a variety of vehicle motions. A realistic, immersive VR system is proposed with 3D graphics, haptic motion input devices, 3D surround-sound audio, articulating fans, and an olfactory generator. The real-world cockpit and input devices will be used to increase realism, suspended from nine active cables for motion simulation. The intent is to replace existing heavy, expensive, and dangerous Stewart-Platform-based flight simulators with a lighter, more economical, stiff, safe, high bandwidth, cable-suspended system. Many potential applications are proposed in addition to flight simulation. Our long-term goal is to create an economical, safe, realistic vehicle simulator with full-body motion for operator training, research & development, vehicle design, entertainment, rehabilitation, and therapy.
Application of a Product Platform Knowledge Management Methodology Using the Semantic Web Paradigm to a Playground System
Authors: Hart Kathleen M. , Shooter Steven B. , Simpson Timothy W.
Published: May 2009

Information management has been recognized as an essential ingredient for effective product family planning strategies through the utilization of product platforms. Product platforms utilize commonality of parts, modules, and processes during design and manufacture. This commonality must be well documented for its effective use, and ontologies are one way to organize this information to promote knowledge management. The following provides a case study to verify a proposed methodology for product platform knowledge management that uses the semantic web paradigm by applying it to a component from a major modular playground equipment producer. Our objective is to verify the developed methodology using a case study of a modular playground component and to evaluate the methodology’s user adoptability. It will be shown that the methodology is successful and valid to apply to other applications, with some improvements, in the future.
Contact Stress Reduction Mechanisms for the CAM-Based Infinitely Variable Transmission
Authors: Lahr Derek F. , Hong Dennis W.
Published: May 2009

The Cam-based Infinitely Variable Transmission (IVT) is a new type of ratcheting IVT based on a three dimensional cam and follower system which provides unique characteristics such as generating specific functional speed ratio outputs including dwells, for a constant velocity input. This paper presents several mechanisms and design approaches used to improve the torque and speed capacity of this unique transmission. A compact, lightweight, and capable differential mechanism based on a cord and pulley system is developed to double the number of followers in contact with the cam at any time, thereby reducing the contact stress between the followers and the cam surface considerably. A kinematic model governing the motion of this differential is developed and a few experimental results from the prototype are presented, showing an overall increase in performance including a smooth output, a wide gear range, and the ability to shift under load. Plans for future improvements to the design, including an inverted external cam mechanism, is also presented along with the expected performance gains.
Modeling and Simulation of Stochastic Lorenz Systems by Polynomial Chaos Approach
Authors: Li Lin , Sandu Corina
Published: May 2009

The Lorenz problem is one of the paradigms of the chaotic systems, which are sensitive to initial conditions and for which the performance is hard to predict. However, in many cases and dynamic systems, the initial conditions of a dynamic system and the system parameters can’t be measured accurately, and the response of the system must indeed be explored in advance. In this study, the polynomial chaos approach is used to handle uncertain initial conditions and system parameters of the Lorenz system. The method has been successfully applied by the authors and co-workers in multi-body dynamics and terrain profile and soil modeling. Other published studies illustrate the benefits of using the polynomial chaos, especially for problems involving large uncertainties and highly nonlinear problems in fluid mechanics, structural vibrations, and air quality studies. This study is an attempt to use the polynomial chaos approach to treat the Lorenz problem, and the results are compared with a classical Monte Carlo approach. Error bars are used to illustrate the standard deviation of the system response. Different meshing schemes are simulated, and the convergence of the method is analyzed.
Vibrations of a Flexible-Link Flexible-Base Robot Arm
Authors: Emam Samir E.
Published: May 2009

Dynamics and vibrations of flexible robot arms have received considerable attention in recent years. The flexibility of the arm affects the function of the robot and complicates its dynamics as well. Generally, the base of the robot arm has some elasticity, which also affects the precision of its function. We model the robot arm as a flexible beam moving in a vertical plane and resting on two springs: one is in the vertical direction and the other one is in the rotational direction. A lumped mass, which simulates the payload, is attached to the tip of the beam. The beam translates and rotates as a rigid body and moreover it deforms in the lateral direction. The extended Hamilton principle is used to derive the governing equations of motion and their corresponding boundary conditions. We obtained three coupled differential equations: two ordinary-differential equations governing the rigid-body motion of the arm and a partial differential equation governing its deformation. An exact solution for the natural frequencies and mode shapes of the vibrations of the arm about an equilibrium position is obtained. The significance of the effect of the flexibility of the link and the base and the ratio of the mass at the tip point to the mass of the beam on the natural frequencies and mode shapes is investigated.
Contact Stress Analysis of Gear of Crane Gearbox
Authors: Wang Zhonglai , Yang Bo , Huang Hong-Zhong , Miao Qiang , Ling Dan
Published: May 2009

Gears are widely used in many practical engineering to transmit torque. In the process of meshing, contact stress will be produced which causes pitting. Shock becomes more and more serious with the increase of pitting and the probability of failure of meshing gears increases. Contact stress analysis is necessary and important to increase the reliability of gear transmission. In this paper, a fuzzy Hertz approximate optimization method and finite element method are used to deal with a practical engineering problem.
Static Analysis of Crane Gearbox QJC-D900
Authors: Zhang Xiaoling , Miao Qiang , Huang Hong-Zhong , Ling Dan , Wang Zhonglai
Published: May 2009

In this paper the 3D model of the three stage helical gearbox was establish using UNIGEAPHICS (UG) firstly, and then the structure static analysis was realized by ANSYS. Accordingly the gear-box’ stress distribution, deformation can be obtained, so the strength and stiffness of the gear-box can be calculated based on the stress and the deformation results, which helps us to evaluate whether the design demand can be satisfied or not. The structure static analysis provides suggestions for the improvement of model design, and the finite element simulation to the large, heavy-duty gear-box reducer can provide technical assurance for the dependability of the production.
Parameter Estimation for Weibull Distribution Using Support Vector Regression
Authors: Ling Dan , Huang Hong-Zhong , Miao Qiang , Yang Bo
Published: May 2009

The Weibull distribution is widely used in life testing and reliability studies. Weibull analysis is the process of discovering the trends in product or system failure data, and using them to predict future failures in similar situations. Support Vector Regression is a machine learning method based on statistical learning theory, which has been applied successfully to solve forecasting problems in many fields. In this paper, support vector regression is used to build a parameter estimating model for Weibull distribution. Numerical examples are presented to show good performance of this method.
A Necessary and Sufficient Condition for the Genericity of Serial Manipulators
Authors: Mu¨ller Andreas
Published: May 2009

Transverse-regularity is a point-wise manipulator property, ensuring that the singular set Σ is locally a smooth manifold. A generic manipulator is one which is transverse-regular in any configuration. The contribution of this paper is a necessary and sufficient condition for transverse-regularity. The condition is based on the manipulator’s joint screws and their screw products. An expression for the tangent space to Σ at transverse-regular singularities is derived. It is shown that a manipulator is non-generic if it can attain a pose where the rank of the manipulator’s screw system together with the screw products is not the maximal rank of the Jacobian. A necessary and sufficient criterion for degree-one singularities is given in terms of the mechanism’ joint screws. In particular, any non-redundant manipulator is transverse-regular in a degree-one singularity.
A Product Platform Development Method Using QFD
Authors: Park Jaeil , Shin Dongmin
Published: May 2009

Quality Function Deployment (QFD) was initially developed to aid in designing a quality product by interconnecting customer needs in a market segment with technical requirements. Although it assists in improving product quality, it does not have a function to examine technical requirements across the major market segments serviced by a company’s product lines and to aid in developing product platform concepts. In this paper, we present a product platform development method using QFD that aids in developing platform concepts as well as improving the understanding of product family design. This method includes platform planning and platform concept exploration. Platform planning describes the extent to which a variety of products share common components, and platform concepts then are explored, which are the arrangement of common components. This paper uses an electric razor example to illustrate the proposed method.
Quantification Method of Diverse Kansei Quality for Emotional Design: Application of Product Sound Design
Authors: Yanagisawa Hideyoshi , Murakami Tamotsu , Noguchi Shogo , Ohtomi Koichi , Hosaka Rika
Published: May 2009

This paper proposes a quantification method of a product’s emotional quality, which we call kansei quality, with attention paid to its diversity to support the affective design. The customer’s sensitivity towards such a quality differs from person to person due to perception gaps and ambiguity. The proposed method helps the designer to grasp such diverse sensitivities of customers. In contrast to the conventional approach that aims to generalize human sensitivity using average results of sensory tests, the proposed method divides an emotional quality based on differences among the customers’ sensitivity. We apply the proposed method for designing a machine sound in which the designer deals with the sound quality as a kansei quality. We carry out an impression evaluation experiment on human subjects using existing product sounds. To demonstrate the effectiveness of the method, we compare the proposed method with the conventional approach using experimental results. The comparison results show the advantages of the method, such as the avoidance of meaningless average data caused by canceling out multiple different sensitivities. Based on the proposed method, we developed a prototype system that enables the designer to evaluate the kansei qualities of a created sound without conducting a sensory test.
Sensitivity of System Boundary Conditions on the Migration of Low Frequency Modes Controlling Longitudinal Vehicle Response
Authors: Pawar Jasjit , Biggs Sean , Jones R. P.
Published: May 2009

Vehicle driveability is increasingly used as a key measure in media evaluations, and is refined aggressively to differentiate and position the product within its market segment. This is a highly complex system level issue, and encompasses the non-linear interactions between the driveline, suspension and powerunit mounting hardware. The driveability character of the vehicle has typically been tuned through calibration in the later stages of development. Through the use of physical prototypes, such activities have typically been performed on the basis of subjective assessments, to achieve a balanced compromise with other vehicle attributes such as ride, handling and refinement. This paper introduces a model-based approach to facilitate design and detailed analysis early in the product development process, thereby reducing reliance on physical prototypes and the need to implement late design changes. A detailed non-linear mathematical model has therefore been developed in order to characterise the low frequency, longitudinal behaviour of a prototype, four-wheel drive vehicle both in the time and frequency domains. In conjunction with full vehicle test measurements, the analytical model has been validated and then used to investigate a low frequency, fore-aft vehicle oscillation issue that was identified specifically during part throttle pullaway events in cold climate testing.
Application of Interactive Deformation to Assembled Mesh Models for CAE Analysis
Authors: Masuda Hiroshi , Ogawa Kenta
Published: May 2009

Mesh deformation, which is sometimes referred to as mesh morphing in CAE, is useful for providing various shapes of meshes for CAE tools. This paper proposes a new framework for interactively and consistently deforming assembly models of sheet structure for mechanical parts. This framework is based on a surface-based deformation, which calculates the vertex positions so that the mean curvature normal is preserved at each vertex in a least squares sense. While existing surface-based deformation techniques cannot simultaneously deform assembly mesh models, our method allows us to smoothly deform disconnected meshes by propagating the rotations and translations through disconnected vertices. In addition, we extend our deformation technique to handle non-manifold conditions, because shell structure models may include non-manifold edges. We have applied our method to assembly mesh models of automobile parts. Our experimental results have shown that our method requires almost the same pre-processing time as existing methods and can deform practical assembly models interactively.
Active Damping of Vibrations of a Cantilever Beam by Axial Force Control
Authors: Pumho¨ssel Thomas , Ecker Horst
Published: May 2009

In several fields, e.g. aerospace applications, robotics or the bladings of turbomachinery, the active damping of vibrations of slender beams which are subject to free bending vibrations becomes more and more important. In this contribution a slender cantilever beam loaded with a controlled force at its tip, which always points to the clamping point of the beam, is treated. The equations of motion are obtained using the Bernoulli-Euler beam theory and d’Alemberts principle. To introduce artificial damping to the lateral vibrations of the beam, the force at the tip of the beam has to be controlled in a proper way. Two different methods are compared. One concept is the closed-loop control of the force. In this case a nonlinear feedback control law is used, based on axial velocity feedback of the tip of the beam and a state-dependent amplification. By contrast, the concept of open-loop parametric control works without any feedback of the actual vibrations of the mechanical structure. This approach applies the force as harmonic function of time with constant amplitude and frequency. Numerical results are carried out to compare and to demonstrate the effectiveness of both methods.
Nonlinear Normal Modes and Localization in Elastic Vibro-Impact Systems With Multiple Constraints
Authors: Wagg David
Published: May 2009

In this paper we consider the dynamics of compliant mechanical systems subject to combined vibration and impact forcing. Two specific systems are considered; a two degree of freedom impact oscillator and a clamped-clamped beam. Both systems are subject to multiple motion limiting constraints. A mathematical formulation for modelling such systems is developed using a modal approach including a modal form of the coefficient of restitution rule. The possible impact configurations for an N degree of freedom lumped mass system are considered. We then consider sticking motions which occur when a single mass in the system becomes stuck to an impact stop, which is a form of periodic localization. Then using the example of a two degree of freedom system with two constraints we describe exact modal solutions for the free flight and sticking motions which occur in this system. A numerical example of a sticking orbit for this system is shown and we discuss identifying a nonlinear normal modal basis for the system. This is achieved by extending the normal modal basis to include localized modes. Finally preliminary experimental results from a clamped-clamped vibroimpacting beam are considered and a simplified model discussed which uses an extended modal basis including localized modes.
The Effect of Form on Attributing Meanings to Materials
Authors: Karana Elvin , van Weelderen Wikke , van Woerden Ernst-Jan
Published: May 2009

Materials in product design used to be selected based especially on manufacturability concerns and technical aspects such as strength, conductivity, elasticity, etc. Nowadays, the increasing recognition for more intangible issues like meaning attribution or creating emotions in product design made designers shift their focus towards the intangible aspects in their materials selection activity as well. In this research, we aim to concentrate particularly on attributing meanings to materials. It is crucial to realize that several aspects (function, use, context, user, etc.) can be effective in attributing meanings to materials and they should be taken into consideration during the selection process. In this paper, we focus intensively on one of these aspects: the effect of form on attributing meanings to materials. The paper consists of four related studies exploring how people associate some forms with some particular materials and weather form can be effective in changing these ascribed meanings, or not.
Comparison of Modal Parameter Estimation Techniques for Electromechanical Rotordynamics of Cage Induction Motors
Authors: Holopainen Timo P. , Aatola Seppo A. , Cloud C. Hunter , Li Guoxin
Published: May 2009

Electromagnetic fields in the air gap of an electric motor produce electromagnetic forces between the rotor and stator. These forces couple the electromagnetic system to the mechanical one. This electromechanical interaction changes the vibration behaviour of the machine, and it may decrease the critical speeds, induce additional damping or cause rotordynamic instability. The experimental validation of theoretical models of these effects requires modal parameter estimation techniques which are reliable and robust. The main aim of this paper is to compare available techniques for the modal parameter estimation. The studied methods were: a) peak picking, b) prediction error, c) polyreference least-squares complex frequency-domain, d) multiple output backward autoregression, and e) polyreference least-squares complex exponential. Experimental data for the comparison was obtained using a standard six-pole 18 kW induction motor equipped with a long flexible shaft. In addition, the theoretical values using a simple electromechanical rotor model were calculated for the test cases. Comparison showed the short-comings of traditional frequency domain techniques and some advantages of the modern frequency- and time-domain techniques.
Evaluation of a Low-Noise Formate Spiral-Bevel Gear Set
Authors: Lewicki David G. , Woods Ron L. , Litvin Faydor L. , Fuentes Alfonso
Published: May 2009

Studies to evaluate low-noise Formate spiral-bevel gears were performed. Experimental tests were performed on the OH-58D helicopter main-rotor transmission in the NASA Glenn 500-hp Helicopter Transmission Test Stand. Low-noise Formate spiral-bevel gears were compared to the baseline OH-58D spiral-bevel gear design, a high-strength design, and previously tested low-noise designs (including an original low-noise design and an improved-bearing-contact low-noise design). Noise, vibration, and tooth strain tests were performed. The Formate design showed a decrease in noise and vibration compared to the baseline OH-58D design, and was similar to that of the previously tested improved-bearing contact low-noise design. The pinion tooth stresses for the Formate design significantly decreased in comparison to the baseline OH-58D design. Also similar to that of the improved bearing-contact low-noise design, the maximum stresses of the Formate design shifted toward the heel, compared to the center of the face width for the baseline, high-strength, and previously tested low-noise designs.
Using Maximum Likelihood Estimation to Estimate Kriging Model Parameters
Authors: Martin Jay D.
Published: May 2009

A kriging model can be used as a surrogate to a more computationally expensive model or simulation. It is capable of providing a continuous mathematical relationship that can interpolate a set of observations. One of the major issues with using kriging models is the potentially computationally expensive process of estimating the best model parameters. One of the most common methods used to estimate model parameters is Maximum Likelihood Estimation (MLE). MLE of kriging model parameters requires the use of numerical optimization of a continuous but possibly multi-modal log-likelihood function. This paper presents some enhancements to gradient-based methods to make them more computationally efficient and compares the potential reduction in computational burden. These enhancements include the development of the analytic gradient and Hessian for the log-likelihood equation of a kriging model that uses a Gaussian spatial correlation function. The suggested algorithm is very similar to the Scoring algorithm traditionally used in statistics, a Newton-Raphson gradient-based optimization method.
Knowledge Based Design of 3D Electronic Circuit Carriers
Authors: Kaiser Ingo A. , Frank Ursula , Gausemeier Juergen
Published: May 2009

Miniaturization, high reliability and low manufacturing costs require close spatial integration of mechanics and electronics. New production technologies such as MID (Molded Interconnect Device), which enables to manufacture three-dimensional circuit carriers and replace conventional PCBs, open up interesting perspectives in this context. These production technologies cause strong interdependencies between product design and manufacturing; they usually determine the product concept. These interdependencies are often not known to the designers. The design of systems with technologies like MID thus needs a design-supporting knowledge base to overcome this lack of information. This paper describes a knowledge base for the design of three-dimensional electronic circuit carriers in MID. The knowledge base provides the developer with adapted procedural models for the specific design task, which show the mentioned interdependencies, as well as appropriate guidelines and standards during the different design phases. Thus the necessary information is available to the designer at all times. The application of the knowledge base is shown by the example of the housing of an autonomous miniature robot. The miniature robot is manufactured in large numbers. It serves as a test bed for swarm intelligence and multi-agents applications in computer science as well as for the employment of the Technology MID.
Discrete Spectral Modelling of Continuous Structures With Fractional Derivative Viscoelastic Behaviour
Authors: Catania Giuseppe , Sorrentino Silvio
Published: May 2009

Fractional derivative rheological models were recognised to be very effective in describing the viscoelastic behaviour of materials, especially of polymers, and when applied to dynamic problems the resulting equations of motion, after a fractional state-space expansion, can still be studied in terms of modal analysis. But the growth in matrix dimensions brought about by this expansion is in general so fast as to make the calculations too cumbersome. In this paper a discretization method for continuous structures is presented, based on the Rayleigh-Ritz method, aimed at reducing the computational effort. The solution of the equation of motion is approximated by a linear combination of shape-functions selected among the analytical eigenfunctions of standard known structures. The resulting condensed eigen-problem is then expanded in a low dimension fractional state-space. The Fractional Standard Linear Solid is the adopted rheological model, but the same methodology could be applied to problems involving different fractional derivative linear models. Examples regarding two different continuous structures are proposed and discussed in detail.
Numerical Prediction of Evaporation Processes in Porous Media Combustors
Authors: Periasamy C. , Saboonchi A. , Gollahalli S. R.
Published: May 2009

This paper presents a numerical study of evaporation characteristics of liquid fuel spray in porous media. A two-energy equation model was employed to predict solid and gas phase temperatures. Governing equations were solved on a two-dimensional axisymmetric computational domain of 2.15 × 20 cm. An air-blast atomizer model was used to inject kerosene fuel spray on to the porous medium. Combustion in porous media was simulated by using a uniform volumetric heat source in the porous region. Numerical results were obtained with a commercial code Fluent 6.0. For a heat feedback rate of 1% of average heat input, the porous medium attained a temperature of 465 K. This data agreed well with experimental data obtained by infrared imaging. With an increase in heat feedback rate, the porous medium temperature also increased. Surface temperature distribution in porous media for different heat feedback rates was predicted. Results indicate that the transverse distribution was uniform within 1.5% of the mean value. Droplet diameter was smaller in spray core upstream of porous medium and increased radially due to the swirling action imparted to the atomizing air. Transverse vapor concentration results downstream of porous medium show that the distribution was uniform within 5% of the mean value, which demonstrates that porous medium uniformly distributes the fuel vapor-air mixture. The spatially homogeneous reactant mixture is important to achieve good combustion, reduce pollutant formation, and minimize instabilities in practical combustors. Effects of equivalence ratio and flame temperature on transverse vapor concentration profiles were also numerically studied. Porous media combustors could be used in gas turbine and industrial burner applications to reduce pollutant emissions.
Reducing the Number of Variables in a Response Surface Approximation: Application to Thermal Design
Authors: Gogu Christian , Haftka Raphael T. , Bapanapalli Satish K. , Sankar Bhavani V.
Published: May 2009

Response surface approximations (RSA) are a common tool in engineering, often constructed based on finite element (FE) simulations. For some design problems, the FE models can involve a high number of parameters. However it is advantageous to construct the RSA as function of a small number of variables. The purpose of this paper is to demonstrate that a significant reduction in the number of variables needed for an RSA is possible through physical reasoning, dimensional analysis and global sensitivity analysis. This approach is demonstrated for a transient thermal problem, but it is applicable to any FE based surrogate model construction. The thermal problem considered is the design of an integrated thermal protection system (ITPS) for spacecraft reentry where an RSA of the maximum bottom face temperature was needed. The FE model used to evaluate the maximum temperature depended on 15 parameters of interest for the design: 9 thermal material properties and 6 geometric parameters of the ITPS panel. A small number of assumptions simplified the thermal equations allowing easy nondimensionalization, which together with a global sensitivity analysis showed that the maximum temperature mainly depends on only two nondimensional parameters. These were selected to be the design variables of the RSA for maximum temperature. The RSA was still fitted to the original non-simplified FE simulations. Having only two variables allowed a dense design of experiments thus providing a very good quality of fit. Consequently the major error remaining in the RSA is due to the fact that the two nondimensional variables account for only part (albeit the major part) of the dependence on the original 15 variables. This error was checked and good agreement was found. The two-dimensional nature of the RSA allowed graphical representation, which was used for material selection from among hundreds of possible materials for the design optimization of an ITPS panel.
Pre-Programmed Failure Behavior Using Biology-Inspired Structures
Authors: Bay Brian , Bailey Mike
Published: May 2009

Core (filler) materials are key components of the sandwich panel and box-beams that are used in the design of lightweight structures. They perform a variety of elastic-range functions such as transferring and supporting working stresses and energy and collapse management. There is an increasing demand, however, for post-yield performance characteristics such as buckling control, impact toughness, and maintenance of component strength after damage. Low density is also an important consideration, as overall component mass is critical in most applications. These cellular solids need to perform well under normal working stress conditions, yet still resist damage from simple and unavoidable low velocity impacts. A new design approach is suggested by biological systems that have evolved for toughness and damage tolerance (bones, trees, plants, corals, etc.). These systems share the relatively low density cellular arrangements of common synthetic core materials, but also exhibit variable density gradients within the core. (Figures 1 and 2) This paper describes engineering design methods that are inspired by such biology. The result is that a design’s failure modes can be more effectively “designed-in”, controlling locations and amounts of failure.
A Process Model and Data Mining to Support Designing Families of Services
Authors: Moon Seung Ki , Simpson Timothy W. , Kumara Soundar R. T.
Published: May 2009

Product family design is a cost-effective way to achieve mass customization by allowing highly differentiated products to be developed from a common platform while targeting individual products to distinct market segments. Recent trends seek to apply and extend principles from product family design to new service development. In this paper, we extend concepts from platform-based product family design to create a novel methodology for module-based service family design. The new methodology helps identify a service platform along with variant and unique modules in a service family by integrating service-based process analysis, ontologies, and data mining. A function-process matrix and a service process model are investigated to define the relationships between the service functions and the service processes offered as part of a service. An ontology is used to represent the relationships between functional hierarchies in a service. Fuzzy clustering is employed to partition service processes into subsets for identifying modules in a given service family. The clustering result identifies the platform and its modules using a platform level membership function. We apply the proposed methodology to determine a new platform using a case study involving a family of banking services.
Finding All Undercut-Free Parting Directions for Solids of Revolution
Authors: Chen Xiaorui , McMains Sara
Published: May 2009

For molding and casting processes, geometries that have undercut-free parting directions (UFPDs) are preferred for manufacturing. However, existing approaches either cannot identify all UFPDs or cannot run at interactive speeds (the best exhaustive algorithm, unimplemented, runs at O(n4) time theoretically). Our proposed feature-based approach avoids testing the whole Gaussian sphere of potential directions by first efficiently identify all UFPDs for individual features such as extruded and revolved features, thus significantly reducing test space and running time. In this paper, we describe a fast algorithm to find all UFPDs for solids of revolution. The algorithm is based on analyzing the constructing 2D generator profiles, building on our previous results for 2-moldability analysis of polygons. The running time is O(n), where n is the geometric complexity of the 2D generator profile. For parts containing multiple solids of revolution, the set of possible UFPDs can be significantly reduced based upon an analysis of each such feature, efficiently identifying many as non-2-moldable or reducing the search space for exhaustive algorithms that find all UFPDs.
Increasing in Reliability of Power Transmissions Bearings by Surface Modification and Coating
Authors: Tesker Efim , Tesker Sergey , Sirotin Victor , Salolykin Michael , Yakovlev Nicolay
Published: May 2009

The data of applied research aimed at new laser surface modification technologies development are presented in this paper. Both polymer and metal surface coatings formed on steel parts under laser radiation have been tested and their influence on the friction conditions, reliability, bearing capacity and durability of the drive item have been investigated. The relationships between laser treatment modes, coatings composition and various exploitation parameters have been obtained. It is shown that the worked out technologies, to be used in production, provide power transmissions bearings with increased reliability and operating properties.
Kinematics and Pose Estimation for Cable Actuated Parallel Manipulators
Authors: Theodorakatos Dimitris , Stump Ethan , Kumar Vijay
Published: May 2009

Parallel manipulators have many attractive features, such as a high strength to weight ratio, with great potential for applications in manufacturing and construction industry. Cable actuated parallel manipulators are a special case of parallel robots, where the limbs are replaced by cables, offering increased scalability of the structure. However, cable actuated manipulators have larger errors in positioning because of cable extensions and changes in the effective spool diameter. Also, the direct kinematics solution is no longer meaningful once the robot crosses the workspace boundary. Finally, it is necessary to start from a pre-calibrated home position where the cable lengths are known. In this work we address the pose estimation and control for a cable robot using visual and inertial measurements as well as information from the direct kinematics. We demonstrate the algorithm on a prototype with a working volume of 2m × 4.6m × 6m.
Towards Sensor Enhanced Virtual Reality Teleoperation in a Dynamic Environment
Authors: Kadavasal Muthukkumar S. , Oliver James H.
Published: May 2009

A teleoperation interface is introduced featuring an integrated virtual reality based simulation augmented by sensors and image processing capabilities on-board the remotely operated vehicle. The virtual reality system addresses the typical limitations of video-based teleoperation caused by signal lag and limited field of view, allowing the operator to navigate in a continuous fashion. The vehicle incorporates an on-board computer and a stereo vision system to facilitate obstacle detection. It also enables temporary autonomous operation of the vehicle for local navigation around obstacles and automatic re-establishment of the vehicle’s teleoperated state. Finally, the system provides real time update to the virtual environment based on anomalies encountered by the vehicle. System architecture and preliminary implementation results are discussed, and future work focused on incorporating dynamic moving objects in the environment is described.
Damage Assessment With Nonlinear Vibro-Acoustic Modulation Technique
Authors: Donskoy Dimitri , Zagrai Andrei , Chudnovsky Alexander , Golovin Eduard , Agarwala Vinod
Published: May 2009

Assessment of structural deterioration due to in-service and environmental loads is an essential element in ensuring safety, operability and long life of various structures and structural components. There is an increasing need for technologies that could allow for monitoring material degradation at the micro/meso scale before the onset of the macro-scale fracture. In this contribution, we report results of the real-time monitoring of the material micro/meso scale degradation using the nonlinear acoustic vibro-modulation technique. The technique explores nonlinear acoustic interaction of high frequency ultrasound and low frequency structural vibration at the site of the incipient damage. It is shown that micro/meso scale degradation increases the material nonlinearity leading to modulation of the high frequency ultrasonic signal by low frequency vibration, quantified by the nonlinear acoustic damage index (DI). The correlation of DI measured for hundreds of test coupons with material degradation was confirmed using traditional ultrasonic and SEM examinations.
Nonlinear Oscillations of an Autoparametrical System With Two Coupled Pendulums
Authors: Sado Danuta
Published: May 2009

The nonlinear dynamics of a three degree of freedom autoparametrical vibration system with two coupled pendulums in the neighborhood internal and external resonances is presented in this work. It was assumed that the main body is suspended by an element characterized by non-linear elasticity and non-linear damping force and is excited harmonicaly in the vertical direction. The two connected by spring pendulums characterized are mounted to the main body. It is assumed, that the motion of the pendulums are damped by nonlinear resistive forces. Solutions for the system response are presented for specific values of the uncoupled normal frequency ratios and the energy transfer between modes of vibrations is observed. Curves of internal resonances for free vibrations and external resonances for exciting force are shown. In this type system one mode of vibration may excite or damp another one, and except different kinds of periodic vibration there may also appear chaotic vibration. Various techniques, including chaos techniques such as bifurcation diagrams and: time histories, phase plane portraits, power spectral densities, Poincare` maps and exponents of Lyapunov, are used in the identification of the responses. These bifurcation diagrams show many sudden qualitative changes, that is, many bifurcations in the chaotic attractor as well as in the periodic orbits. The results show that the system can exhibit various types of motion, from periodic to quasi-periodic to chaotic, and is sensitive to small changes of the system parameters.
Sonar Map Construction for Ubiquitous Robotic System Using a Footprint Association Filter
Authors: Lee Yu-Cheol , Yu Wonpil , Lim Jong-Hwan , Chung Wan Kyun , Cho Dong-Woo
Published: May 2009

This paper presents a method for building a probability grid map for autonomous mobile robots with ultrasonic sensors using a footprint association filter (FAF). The method is based on evaluating the possibility that the acquired sonar data are all reflected by the same object. The FAF is able to associate data points with each other. Data affected by specular reflection are not likely to be associated with the same object, so they are excluded from the data cluster by the FAF, thereby improving the reliability of the data used for the probability grid map. Since the corrupted data are not used to update the probability map, it is possible to build a good quality grid map even in a specular environment. The FAF was applied to the Bayesian probability models, which are typical models used to build grid maps, to verify its effectiveness. Experimental results were also obtained using a mobile robot in a ubiquitous home environment.
An Optimal Design Method for Reducing Brake Squeal in Disc Brake Systems
Authors: Matsushima Toru , Nishiwaki Shinji , Yamasaki Shintarou , Izui Kazuhiro , Yoshimura Masataka
Published: May 2009

Minimizing brake squeal is one of the most important issues in the development of high performance braking systems. Recent advances in numerical analysis, such as finite element analysis, have enabled sophisticated analysis of brake squeal phenomena, but current design methods based on such numerical analyses still fall short in terms of providing concrete performance measures for minimizing brake squeal in high performance design drafts at the conceptual design phase. This paper proposes an optimal design method for disc brake systems that specifically aims to reduce brake squeal by appropriately modifying the shapes of the brake system components. First, the relationships between the occurrence of brake squeal and the geometry and characteristics of various components is clarified, using a simplified analysis model. Next, a new design performance measure is proposed for evaluating brake squeal performance and an optimization problem is then formulated using this performance measure as an objective function. The optimization problem is solved using Genetic Algorithms. Finally, a design example is presented to examine the features of the optimal solutions and confirm that the proposed method can yield useful design information for the development of high performance braking systems that minimize brake squeal.
The Dynamic Transmission Error and the Tooth Meshing Force Based on ANSYS/LS-DYNA
Authors: Chen Siyu , Tang Jinyuan , Liu Xin
Published: May 2009

Two dynamic models of meshing contact in gear transmission are established. The transient dynamic characteristics of the gear transmission along line of action were analyzed based on deformable-body model and discrete parameter model. The curves on the displacement, the speed and the meshing force of the gear tooth meshing node with the change of time were gotten. Dynamic transmission error curves and teeth loads were computed within a wide range of rotational speed for different torques and working conditions with and without friction force. The results of the dynamic transmission error and dynamic teeth loads are validated by comparing the calculating results with that of the former experimental data. The research provides basic data for analyzing the gear impact and predicting the fatigue life of gear tooth, and it is also beneficial for the optimum design of gear parameters and the understanding of the dynamic phenomenon of gear meshing impact.
Development of Nonlinear Coupled Mode Bushing Model Based on the Bouc-Wen Hysteretic Model
Authors: Ok Jin-Kyu , Sohn Jeong-Hyun , Yoo Wan-Suk
Published: May 2009

In this paper, a coupled bushing model for vehicle dynamics analysis based on the Bouc-Wen hysteretic model is proposed. Bushing components of a vehicle suspension system are tested to capture the nonlinear and behavior of the typical rubber bushing elements using MTS machine. Test results are used to define the parameters of the Bouc-Wen bushing model. The Bouc-Wen model is employed to represent the hysteretic characteristics of the bushing. A coupled relation for radial mode and torsional mode are suggested. Model parameters are obtained by using the genetic algorithm, and sensitivity indices of parameters are also extracted from the sensitivity analyses. ADAMS program is used for the identification process and VisualDOC program is employed to find the optimal parameters of the proposed model. A half-car simulation is carried out to validate the proposed bushing model.
The Research of Multiple Axes Chain Coupler Method for Automotive Engine Systems
Authors: Jung Enu-Kyo , Choi J. H. , Jang Kyung-Chun , Ryu Han-Sik , Yang Seong-Ho
Published: May 2009

In power transmission area, researchers have carried out multi-body systems analysis regarding timing belt train and timing chain train systems. And past several years there has been increasing interest in analysis of power transmission system related with nonlinear contact, small mass link segments and high speed problem. In these kinds of analysis, solving time is taken a lot to get numerical results according to complicate characteristics of the systems. Because the behavior of link segments is the one of most significant facts from getting accurate numerical results point of view in detail design. However, in earlier step of systemic design, one of the most important points is to extract a trend of systemic behavior in short time. In this study, multiple axes chain coupler is presented in order to apply to systemic design. The object of this approach is to help to get systemic trend in the early design step. In this approach, first, screw force is used to represent tension and torque acting on the system. Second, distance change between timing chain sprockets is applied to represent vibration of sprockets. Third, stiffness coefficient and damping coefficient are used to generate tension and torque. A timing chain system, which consists of chain sprockets, chain link segments and guide rails, is used for validation comparing with proposed method. As a result of these approaches, multiple axes chain coupler enables to get reasonable systemic trend comparing with multi-body system of timing chain in short time.
Dynamic Characteristics of a Mistuned Heat Exchanger in Cross-Flow
Authors: Huang Bo-Wun , Kung Huang-Kuang , Kuang Jao-Hwa
Published: May 2009

The dynamic behaviors of tubes of a heat exchanger are frequently affected by the existence of local flaw. These tubes are worn from the hot-cold fluid shock waves. This local defect may alter the tube dynamics and introduce mode localization in the periodically arranged tube array. The variation of the dynamic characteristics of a component cooling water heat exchanger with wear tubes in cross-flow is investigated in this study. Periodically coupled cooling tubes are used to approximate a heat exchanger. Each tube is considered to be coupled to adjacent tubes through the squeezed water film in the gaps. This work addresses the probability of mode localization is occurring in a heat exchanger in cross-flow. A dynamic model of the coupled tube bundle is proposed. The numerical results reveal that the local defect in a tube array may introduce the so-called mode localization phenomenon in a periodically coupled tube bundle.