bluuebunny/crossref_metadata_2025 huggingface dataset:
Towards a Computational Framework for Energy Estimation: Needs, Requirements, and Its Generic Shell
Authors: Huang He , Ameta Gaurav
Published: March 2011

Excessive energy consumption has become a worldwide issue in today’s design and manufacturing industry. A framework for estimating energy consumption that could later be used to integrate with CAD/CAM systems is in demand. This paper initially presents needs and requirements for a computational framework to estimate energy consumption during a product life-cycle, i.e., from extraction of raw materials to recycling or disposal. Energy estimations allow for asset management, thereby reducing the negative impacts of the product to the environment. At the manufacturing stage, asset management can be based on energy efficient process planning and scheduling. As a first step, the research presented in this paper proposes a framework that represents a generic shell for computing energy.
Mobility Identification of a Group of Single Degree-of-Freedom Eight-Bar Linkages
Authors: Wang Jun , Ting Kwun-Lon
Published: March 2011

This paper presents the first complete and automated mobility identification method for a group of single-DOF planar eight-bar linkages and thus represents a breakthrough on the recognition and understanding of complex linkage mobility. The mobility identification in this paper refers to the configuration space, the range of motion, and configuration recognition. It is a troublesome problem encountered in any linkage analysis and synthesis. The problem becomes extremely confusing with complex multiloop linkages. The proposed approach is simple and straightforward. It recognizes that the loop equations are the mathematical fundamentals for the formation of branches, sub-branches, and other mobility issues of the entire linkage. The mobility information is then extracted through the discriminant method. The paper presents complete answers to all typical mobility issues, offers the mathematical insight as well as explanation on the effects of multiple loops via joint rotation space, and casts light for treating the mobility problems of other complex linkages. The merits of the discriminant method for mobility identification are clarified and examples are employed to showcase the proposed method. The computer-aided automated mobility analysis of eight-bar linkages is made possible for the first time.
Merging Machining and Measurement for Cognitive Manufacturing
Authors: Zhao Yaoyao F. , Proctor Frederick M. , Horst John A. , Xu Xun
Published: March 2011

Machining process planning and measurement process planning have long received research attention from industry and academia. Machining and measurement process automation is well established for mass production in today’s manufacturing systems. However, over the years manufacturing systems have evolved in response to many external drivers including the introduction of new manufacturing technologies and materials, the constant evolution of new products and the increased emphasis on quality as well as the escalating global competition and pressing need for responsiveness, agility and adaptability. These external drivers compel the realization of cognitive manufacturing, in which machining and measurement are merged together to form a more informed, more flexible, and more controlled manufacturing environment. In this way, when unforeseen changes or significant alternations happen, machining process planning systems can receive on-line measurement results, make decisions, and adjust machining operations accordingly in real-time. This paper presents a new paradigm of process planning research and outlines the way to reach cognitive manufacturing. An integrated machining and measurement process planning prototype system has been developed and tested with case studies.
Functional Similarity at Varying Levels of Abstraction
Authors: Caldwell Benjamin W. , Mocko Gregory M.
Published: March 2011

Function modeling is often used in the conceptual design phase as an approach to capture a form-independent purpose of a product. Current research efforts have focused on the formalization of functional models, development of function-based design repositories, and concept generation based on a quantitative functional similarity metric. In this paper, three levels of abstraction of function models are obtained by including supporting functions, excluding supporting functions, and applying abstraction rules to function models of 128 products in a design repository. The similarity of these products is computed using the Functional Basis controlled vocabulary and a matrix-based similarity metric. A matrix-based clustering algorithm is then applied to the similarity results to identify groups of similar products. A subset of these products is then studied to further compare the three levels of abstraction and to validate the results. Similarity between consumer products depends on the level of abstraction of the models, with higher levels of abstraction producing better results.
Kinematic-, Static- and Workspace Analysis of a 6-P-U-S Parallel Manipulator
Authors: Narayanan Madusudanan Sathia , Chakravarty Sourish , Shah Hrishi , Krovi Venkat N.
Published: March 2011

This paper examines the symbolic kinematic modeling of a general 6-P-U-S (prismatic-universal-spherical) parallel kinematic manipulator (PKM). The base location of actuators has been previously shown to lead to: (i) reduction of the (motor) weight carried by the legs; (ii) elimination of the actuation transmission requirement (through intermediary joints as in the case of the Stewart-Gough platform); and (iii) most-importantly absorption of reaction-forces by the ground. We focus on using the symbolic equations to derive the conditions for type I and II singularities of this class of parallel manipulators. Based on these conditions, this system of equations is specialized to a specific configuration of the platform that has superior structural design and comparatively minimal singularities within its workspace. A series of studies were conducted to investigate the quality of workspace as well as estimate the actuation requirements for a unit payload carried over their workspace using the symbolic Jacobian model for this specialized configuration.
Experimental Validation for an Extended-Stability Electrostatic Actuator
Authors: Towfighian S. , Seleim A. , Abdel-Rahman E. M. , Heppler G. R.
Published: March 2011

A voltage regulator is developed to extend the operation range of a electrostatic actuator using a displacement feedback. The feedback actuator system can be used for continuous position tracking of step, ramp, or harmonic voltage signals. The electrostatic actuator is composed of a micro-cantilever beam electrode above a fixed electrode. The voltage difference between the two electrodes is regulated by the controller to maintain the balance between mechanical and electrostatic forces at large beam deflections, thereby increasing the actuation range. Simulated closed loop system responses with experimentally identified parameters are presented and show the actuation can reach up to 85% of the gap in the static response with an input voltage of less than 12 V. Experimental results show that the controller properly functions and prevents the beam from experiencing pull-in. A close agreement is found between the simulated and measured closed loop model dynamic responses.
Understanding Innovation in Student Design Projects
Authors: Elizondo Luis A. , Kisselburgh Lorraine G. , Hirleman E. Daniel , Cipra Raymond J. , Ramani Karthik , Yang Maria , Carleton Tamara
Published: March 2011

Over the past few years, academic institutions have become aware of the importance of innovation in education, as well as its broader role in strengthening the economy. Creativity and innovative thinking are not easily taught in the classroom, but they can be developed through practice and experience. Evaluating innovation as part of product design courses has thus become very important to increase the probability of students becoming innovators in the real world. Innovation tournaments provide universities with an opportunity to develop innovative design thinking in students while they gain practical experience. Understanding design innovation at a deeper level in the context of student design projects is critical to develop realistic perspectives among students. Determining the appropriate dimensions for understanding and measuring innovation is the main objective of this paper. Toward that objective, we conducted initial experiments in conjunction with an innovation award to develop and assess innovation metrics. The results reveal several dimensions of innovation: differentiability, creativity, need satisfaction, and probability of commercial success emerged as key dimensions. This research also assesses the perception of innovation, contrasting the perceptions of judges from industry with the views of academically oriented judges.
A QFD Approach to the Delivery of an Online Degree
Authors: Cox Leroy R. , Loseke Stacy H.
Published: March 2011

Technology has profoundly changed the manner with which we perform our most basic functions. The innovation of the Internet and other communication media have allowed us to communicate, conduct business, and buy and sell without ever having to leave home. Education has been affected in the same way, as those that would seek to obtain a degree or certification can do so in the comfort of their own homes as opposed to having to commute to a college campus to do so. This paper will discuss how elements of Quality Function Deployment have been used to facilitate a partnership between a traditional university located in western Arkansas and various community colleges in the eastern Arkansas Delta Region. The students in this region are non-traditional, place-bound individuals without access to higher education opportunities, but at the same time, in need of these opportunities to advance in the workplace. This paper will discuss how a university some three hundred miles away is able to deliver a baccalaureate degree to individuals who will most likely never see the college campus. The impact of the initiative as well as particular hurdles and lessons learned thus far will be shared.
In-Service Information for Aeroengine Designers: A Survey
Authors: McSorley Grant , Huet Greg , Fortin Cle´ment
Published: March 2011

One of the primordial aspects of the integrated product service paradigm is efficient flow and sharing of information between the stakeholders during the entire life of a product. This paper presents an improved understanding of the nature of the product in-use information required by aircraft design engineers. The findings are based on a vast survey which expands on a previous qualitative study reported in the literature. The results presented here are therefore a much needed quantitative measure of the in-service information requirements at the aircraft design stage. The survey has helped the authors to depict a system of in-service information feedback to designers which can be qualified as informal in nature, producing inefficient or frustrating results. Indeed, the feedback process is established mainly through personal contacts and does not necessarily ensure that appropriate, complete information is systematically available in a timely manner for designers. On the bright side, the responses from the participants consolidate the belief that the required information does exist within heterogeneous databases and that designers recognize the importance of in-service information to their work. A formalized in-service information feedback process is therefore seen as one of the strategic mechanisms that needs to be implemented to ensure proper product development and service integration.
A Low Voltage Controller for a Chaotic Micro Resonator
Authors: Towfighian S. , Heppler G. R. , Abdel-Rahman E. M.
Published: March 2011

The performance of a chaotic micro resonator is improved by redesigning a quadratic controller reported in a previous study. The chaotic micro resonator is composed of an electrostatic actuator and a voltage regulator (controller). The actuator is made of cantilever beam electrode above a fixed electrode. The actuator voltage, and consequently the electrostatic force magnitude, is controlled to drive the cantilever beam oscillations into chaos by creating a bi-stable regime in the system response. The performance of the redesigned controller is improved such that the system input voltage is reduced. The voltage generated by the controller is halved and the controller gains are smaller, which reduces the power and gain demands on the analogue controller components. The static and dynamic responses of the chaotic oscillator are studied and the sizes of the basins of attraction are compared for the improved and the original quadratic controllers. The controller can be configured to create two potential wells. The excitation DC voltages can then be adjusted to control the size of the upper and lower wells and thereby the basins of attraction around the two stable equilibria. As a result, one can shape the chaotic attractor to meet desired criteria. The reported chaos is intermittent chaos located in the lower well and between the two potential wells. This study can be used to design a new generation of nonlinear oscillators targeting high resolution sensors.
Assessing the Quality of Ideas From Prolific, Early-Stage Product Ideation
Authors: Kudrowitz Barry Matthew , Wallace David R.
Published: March 2011

The goal of many idea generation techniques, such as brainstorming, is to generate a large quantity of ideas with the hopes of having a few outstanding novel ideas that are worth pursuing. The output of such sessions is a large number of rough concept sketches, which require a rapid means of screening to select a manageable set of promising ideas. In this study we develop and test metrics for evaluating large quantities of early-stage product idea sketches. In total, 1767 ideas for three different product themes were used as a test bed. With our findings, we suggest three independent qualities that fully describe an innovative product idea: creative (as a subjective judgment), useful (as defined as having practical applications), and feasible (as determined by experts). Reviewers’ subjective ratings of idea creativity had a strong correlation with ratings of idea novelty (r2 = .80), but negligible correlation with idea usefulness (r2 = .16). The clarity of sketch positively influenced ratings of idea creativity. Another interesting finding is that the quantity of ideas generated by the individual subjects had a strong correlation with that subject’s overall creativity scores (r2 = .82) and novelty scores (r2 = .85), but had weak correlations with that subject’s usefulness scores (r2 = .38).
Dynamics and Energetics of a String Vibrating Against an Obstacle Placed at One Boundary
Authors: AlSahlani Assaad , Mukherjee Ranjan
Published: March 2011

In this paper we investigate the vibration of a string with a rigid obstacle placed at one of its boundaries. During vibration, a portion of the string wraps and unwraps around the obstacle. The impact between the string and the obstacle during wrapping is assumed to be inelastic. The length of the string that wraps around the obstacle, is discretized into a finite number of segments for the purpose of analysis. These segments sequentially collide with the obstacle starting from when the string makes first contact with the obstacle till it comes to rest. During wrapping, the energy of the string is dissipated through impact but during unwrapping the energy is conserved. The geometry of the string at any instant of time is determined from the boundary conditions associated with wrapping and unwrapping of the string. A general solution for vibration against convex obstacles of arbitrary geometry was analysed and numerical simulation results are presented for elliptic- and circular-shaped obstacles with different orientations and for different modes of string vibration. The results show that an obstacle at the boundary can be used as a passive mechanism for vibration suppression. The energy dissipated is found to be greater for higher modes of vibration and for obstacle geometries that result in greater length of wrapping.
Expanded Workspaces of Manipulation Devices Using Friction and Dynamics
Authors: Ringold Tyson L. , Cipra Raymond J.
Published: March 2011

Dynamic or “nonprehensile” grasps that do not rely on a dedicated fixturing device, but instead use dynamic forces to maintain control of an object, reduce the necessary hardware complexity over traditional, “pick-and-place” robotic manipulation strategies. The full workspace of such a manipulator, however, is dependent on the history of the mechanism’s motions and can no longer be determined simply by the geometric constraints imposed by the physical dimensions and limits of the mechanism. As others have previously, we solve the dynamic equations with the imposed kinematic and force constraints, then visualize the extent of motion by observing the limiting trajectories on a phase plane. As opposed to incorporating all constraints initially, however, we examine constraints independent of others before combining. This unobscures how each constraint individually affects the total system ability and gives additional insight during the design phase of a mechanism, where a judicious choice of system parameters is needed. We then describe the utility of this constraint separation by analyzing a simple mechanism useful for lifting operations.
An Optimization Model for Parabolic-Trough Solar Power Generation Systems
Authors: Hamza Karim , Laberteaux Kenneth P. , Saitou Kazuhiro
Published: March 2011

This paper explores the design optimization of parabolic-trough solar power generation systems. In these systems, solar radiation is focused onto receiver tubes in which a thermal carrier fluid is circulated. The collected thermal energy is then used to generate steam that powers a steam turbine to drive an electric generator. An optimization model is constructed that aims to minimize the cost of electric energy produced. In this model, the optimization is concerned with decision variables that affect: i) the solar field and ii) thermal storage. The steam turbine and generator are not part of the optimization model, as they are assumed to use the same off-shelf components that are used in fossil-fuel based power plants. It is understood that decisions concerning the solar field both affect and are affected by the design of the solar collector assemblies (SCAs), which are the support structures that hold the focusing mirrors. Design of the SCAs is a structural optimization problem that aims to minimize the cost of the structure while satisfying dimensional and loading constraints. Genetic algorithm (GA) is used for the optimization of the parabolic trough system model. For every candidate design examined by GA for the solar field and thermal storage, the most suitable structural design of the SCAs is obtained from solving the sub-problem of structural optimization. This “nested” optimization model is made possible by pre-analyzing a large range of SCA designs and recording them as a lookup database. The developed optimization model of the parabolic trough systems allows for parametric studies on how certain incentives, government policies and key technological developments may affect the system design decisions.
A Product Lifecycle Management Framework to Support the Exchange of Prototyping and Testing Information
Authors: Toche Boris , Huet Greg , McSorley Grant , Fortin Cle´ment
Published: March 2011

The modern perspective on product life cycle and the rapid evolution of Information and Communication Technologies in general have opened a new era in product representation and product information sharing between participants, both inside and outside the enterprise and throughout the product life. In particular, the Product Development Process relies on cross-functional activities involving different domains of expertise that each have their own dedicated tools. This has generated new challenges in terms of collaboration and dissemination of information at large between companies or even within the same organization. Within this context, the work reported in this paper focuses on a specific stakeholder within product development activities — the testing department. Its business is typically related to the planning and building of prototypes in order to perform specific tests on the future product or one of its sub-assemblies. This research project aims at investigating how results from testing activities can efficiently interface with other departments, in particular to offer relevant information feedback to designers. As a first step, a study based on an open source initiative is described to show how two natively disparate PLM tools can dialogue to merge information in a central environment. The principles applied in the study are then transposed to introduce a framework where information from prototyping and testing activities could be mapped and merged with design activities to match needs in a cross-functional setting.
A New Approach to Generating Accurate NURBS Cutter Location Paths With Approximate Arc Length Parameter
Authors: Khan Maqsood A. , Chen Zezhong C.
Published: March 2011

For accurate tool trajectories with respect to predetermined NURBS cutter location paths (refer to reference paths) and good tool kinematics in NC machining, many NURBS interpolation algorithms are trying to compute appropriate cutter locations on the paths during machining. Due to the high non-linearity between each interpolating chord (connecting two adjacent cutter locations) and its corresponding path segment, the existing methods can only interpolate the reference path with approximation, resulting in actual cutter trajectory with error beyond the tolerance and large feed rate fluctuations. To address problems of the current interpolation methods in this work, a new type of tool path, NURBS cutter location path with the arc length parameter, is proposed and a new approach to generating accurate paths of this type is provided through re-parameterization of the reference paths with the arc length parameter. The main features of this approach include (1) sampling points and calculating their arc lengths by decomposing an input reference path into Bezier curve segments according to criteria, and (2) fitting a NURBS tool path with the arc length parameter to the sample points until the parameterization error is less than the tolerance. This approach is applied to a benchmark for a NURBS path with the arc length parameter, and this path is then compared with the results generated using three existing interpolation methods, in order to demonstrate the advantage of this new approach.
Laser-Powered Sub-mm Untethered Microrobots
Authors: Pac Muhammed R. , Popa Dan O.
Published: March 2011

The paper discusses the promises and challenges of using laser as a source of energy and means of control for untethered microdevices. Achieving the desired device operation with available controls in the laser signal is a challenge that requires redesign of current microactuators and invention of new ones. In addition, for multiple target spots on a device, the laser beam can be multiplexed or separate lasers can be used simultaneously. Shaping of the control signal based on such variables of the laser as output power, pulse width, and beam spot is a combined effort of accordingly designing the microdevice and selecting the device materials. The paper presents a parametric design evaluation of two versions of stick-and-slip microrobots actuated by commonly used thermal actuators. A detailed parametric analysis with varying actuator geometries predicts that actuation at speeds comparable with electrostatically and electromagnetically actuated microrobots is also possible with laser power. Initial experiments on regular chevron actuators show that pulsed laser can be effectively used to drive microdevices.
Application of Machine Vision Techniques for Fault Diagnostics and System Examination of Braid
Authors: Branscomb David J. , Beale David G. , Broughton Royall M.
Published: March 2011

Important factors of braid formation are yarn motion, yarn tension and intra-yarn frictional forces. In order to improve quality of braided structures the effects of yarn tension and resulting braid formation position must be understood and controlled. This paper reports the effect of yarn tension on braid formation (braid point) motion along with the radial and longitudinal motion of the braid point in the initial, transient, and final positions. Visual observations utilizing low cost webcams are also presented as well as a diagnostic tool which can recognize the onset of defects and provide some insight into what might be causing the fault. Optimal braid performance is observed which serves as the baseline for comparing the behavior of faults. Radial fluctuation of braid point position is a good indicator of mechanical faults of the tensioning mechanisms. The experiments performed will provide the foundation for further work with applications for improving braiding quality in ropes, tethers, and structural composites. Finally, this experimental study and dynamic characterization will be useful for assessing future passive and active control methods, along with sensing.
Amplitude Dependent Dispersion in Essentially Nonlinear Periodic Chains
Authors: Narisetti Raj K. , Ruzzene Massimo , Leamy Michael J.
Published: March 2011

Wave dispersion in one dimensional essentially nonlinear chains is investigated using generalized harmonic balance method. The general approach presented is applied to predict dispersion in nonlinear chains with Hertzian contact interaction [1]. A compressive load at the two ends of a chain determines the magnitude of the nonlinearity. The cut-off frequencies and band-gaps exhibited by mono-atomic and diatomic chains are shown to be amplitude dependent. Amplitude dependent dispersion predicted by harmonic balance method agrees with the trend predicted by perturbation analysis [2]. In contrast to other approximate methods which are limited to small amplitude waves, the main advantage of the harmonic balance method is the ability to examine the high amplitude effects on wave properties. This includes the generation of multi-harmonic frequencies and significant variation in band-structure which can be exploited to design tunable acoustic devices. Applying a numerical algorithm based on generalized harmonic balance framework, the present study depicts a significant variation in band-gap between low and high wave amplitudes in essentially nonlinear periodic chains.
Constraint-Based Synthesis of Shape-Morphing Structures in Virtual Reality
Authors: Vance Judy M. , Dorozhkin Denis
Published: March 2011

This manuscript outlines a novel approach to the design of compliant shape-morphing structures using constraint-based design method. Development of robust methods for designing shape-morphing structures is the focus of multiple current research projects, since the ability to modify geometric shapes of the individual system components, such as aircraft wings and antenna reflectors, provides the means to affect the performance of the corresponding mechanical systems. Of particular interest is the utilization of compliant mechanisms to achieve the desired adaptive shape change characteristics. Compliant mechanisms, as opposed to the traditional rigid link mechanisms, achieve motion guidance via the compliance and deformation of the mechanism’s members. The goal is to design a single-piece flexible structure capable of morphing a given curve or profile into a target curve or profile while utilizing the minimum number of actuators. The two primary methods prevalent in the design community at this time are the pseudo-rigid body method (PRBM) and the topological synthesis. Unfortunately these methods either tend to suffer from a poor ability to generate potential solutions (being more suitable for the analysis of existing structures) or are susceptible to overly-complex solutions. By utilizing the constraint-based design method (CBDM) we aim to address those shortcomings. The concept of CBDM has generally been confined to the Precision Engineering community and is based on the fundamental premise that all motions of a rigid body are determined by the position and orientation of the constraints (constraint topology) which are placed upon the body. Any mechanism motion path may then be defined by the proper combination of constraints. In order to apply the CBDM concepts to the design and analysis of shape-morphing compliant structures we propose a tiered design method that relies on kinematics, finite element analysis, and optimization. By discretizing the flexible element that comprises the active shape surface at multiple points in both the initial and the target configurations and treating the resulting individual elements as rigid bodies that undergo a planar or general spatial displacement we are able to apply the traditional kinematics theory to rapidly generate sets of potential solutions. The final design is then established via an FEA-augmented optimization sequence. Coupled with a virtual reality interface and a force-feedback device this approach provides the ability to quickly specify and evaluate multiple design problems in order to arrive at the desired solution.
Providing Real-World Mechanism Design Experience Through the Early Intervention and Mechanical Engineering (EIME) Project
Authors: Canfield Stephen L. , Smith Lindsay , Bryant Andrew
Published: March 2011

The Early Intervention and Mechanical Engineering (EIME) project provides real-world engineering design experience to undergraduate engineering students while significantly enhancing the services provided to children with special needs in the region surrounding Tennessee Technological University (Upper Cumberland region). These enhanced services are provided through a mutually beneficial collaboration between early intervention and engineering at Tennessee Tech. Engineering students engage in this project as part of a Design of Machinery Course. Student teams are matched with children with needs for novel applications of adaptive and assistive technology to facilitate transitioning of children from early intervention to preschool programs and inclusive environments. The projects are selected to emphasize motion control tasks. Examples include improved mobility, exercise, adaptations for feeding and everyday functioning, and interactive play. The project serves the engineering program by providing real-world design experiences as well as resources to develop and test projects. This paper will describe how the project is integrated into the design of machinery curriculum and present several examples of typical projects. Assessment of student outcomes relative to design and learning experience will be discussed. The paper will conclude with lessons learned and recommendations for future implementation of this project.
Assessing Creativity and Innovation at the Concept Generation Stage in Engineering Design: A Classroom Experiment
Authors: Oman Sarah K. , Tumer Irem Y.
Published: March 2011

This paper explores how to identify creativity factors in the early stages of engineering concept design and how to apply metrics to quantify that creativity. Prototype designs from a junior-level design course over two years are evaluated using design metrics that analyze a set of ideas based on novelty and quality. Further creativity analyses are included to statistically verify that the developed metrics are valid. Innovative products provide companies with a competitive advantage in the market to stimulate the economy. Creativity metrics will enable them to choose innovative designs in the early stages of concept design, reducing time and cost associated with uncreative design implementation. This paper will go into detail about the implementation of an “Innovation Equation” on a real-world set of designs generated by a junior-level mechanical engineering design class and statistical verification of the validity of the analysis results. Conclusions are drawn that detail the ideal procedures needed to create a successful creativity analysis using these methods.
Localized Material Properties Through Nonlinear Dynamics Based Atomic Force Microscopy
Authors: Huang Wei , Dick Andrew J.
Published: March 2011

Due to the intrinsic nonlinearity of the tip-sample interaction forces that are utilized in atomic force microscopy, nonlinear behavior can be observed even under the most ‘ideal’ conditions. While the standard operating modes of the atomic force microscope (AFM) have been developed to minimize this nonlinear behavior, the authors’ work focuses on utilizing a nonlinear response of the AFM probe associated with off-resonance excitation in order to measure local material properties of the sample. Previously, period-doubling bifurcations were identified and studied for an off-resonance excitation condition of two-and-a-half times the fundamental frequency. A relationship was identified between the characteristics of the qualitative response transition and the properties of the probe and sample. For a given probe, the critical separation distance where the period-doubling bifurcation occurs is influenced by the local modulus properties of the sample. This paper details the current effort studying this relationship with the goal of developing a new AFM operation mode for obtaining localized material properties by scanning the sample. The influence of different system parameters on this relationship is studied and preliminary simulation results are presented for a simple scanning process.
Tolerance Allocation of Assemblies Using Fuzzy Comprehensive Evaluation and Decision Support Processes
Authors: Kumar Abhishek , Goksel Lorens , Choi Seung-Kyum
Published: March 2011

Advancements in manufacturing technology significantly impact the design process. The ability to manufacture assembly components with specific tolerances has increased the need for tolerance allocation. This research proposes a framework that overcomes the drawbacks of the traditional tolerance control methods, and reduces subjectivity by using fuzzy set theory and decision support processes. The combination of fuzzy comprehensive evaluation and conjoint analysis facilitate the reduction of subjectivity in the tolerance control process. The application of the framework is demonstrated with two practical engineering problems. Tolerances are allocated for a clutch assembly and an O-ring seal in an accumulator.
Natural Frequencies and Mode Shapes of Slacked Carbon Nanotube NEMS Resonators
Authors: Ouakad Hassen M. , Younis Mohammed I.
Published: March 2011

Estimating accurately the natural frequencies of electrically actuated carbon nanotubes (CNTs) has been the center of research attention over the past few years. Despite this important topic, a robust knowledge is still missing to understand the role of various physical parameters that affect the natural frequencies, such as the stretching of doubly-clamped CNTs, the DC electrostatic force, and the curvature of CNTs with slacks. In this investigation, we use a 2D nonlinear curved beam model (arch) to simulate the coupled in-plane and the out-of-plane motions of a CNT with curvature (slack). We calculate the variation of its natural frequencies and mode-shapes with the level of slack and the DC electrostatic load. Toward this, we derive a reduced-order model using a multi-mode Galerkin procedure based on the mode shapes of the straight unactuated CNT. We calculate the natural frequencies of the slacked CNT for a given voltage by substituting the static solution into the Jacobian of the reduced-order-model and then finding the corresponding eigenvalues. We show various scenarios of mode crossing and mode veering as the levels of slack and DC load are varied.
Product-Service Systems Design Process Based on Activities and Functions
Authors: Kim Yong Se , Lee Sang Won , Maeng Joo Won , Cho Chang K.
Published: March 2011

As consumers demand diverse values reflecting their individual needs and wants from various viewpoints, including economical, ecological and experiential concerns, more comprehensive and more flexible ways to provide values to consumers are desired. Product-Service Systems (PSS) have been proposed as a solution to realize such diverse value provision. In this paper, a systematic methodology for designing PSS based on activities and functions is proposed, which is much different from the case of product design. The proposed PSS design process includes the following six steps: requirement identification and value proposition, stakeholder activity design, PSS functional modeling, function-activity mapping and PSS concept generation, PSS concept detailing and PSS concept prototyping. In the proposed PSS design process, the activities of stakeholders are defined and analyzed via service blueprint. The functions of PSS fulfilling target values are then defined and represented with the specification service providers and service receivers, and they are further decomposed into sub-functions. Then the relationship between stakeholder activities and functions are established by considering associated stakeholders, and the PSS concepts are generated by mapping product and service elements. Sample case studies are conducted to validate the proposed PSS design process.
A Comparison of Information Passing Strategies in System Level Modeling
Authors: Honda Tomonori , Ciucci Francesco , Lewis Kemper , Yang Maria C.
Published: March 2011

Frameworks for modeling the communication and coordination of subsystem stakeholders are valuable for the synthesis of large engineering systems. However, these frameworks can be resource intensive and challenging to implement. This paper compares three frameworks, Multidisciplinary Design Optimization (MDO), traditional Game Theory, and a Modified Game Theoretic approach on the form and flow of information passed between subsystems. This paper considers the impact of “complete” information sharing by determining the effect of merging subsystems. Comparisons are made of convergence time and robustness in a case study of the design of a satellite. Results comparing MDO in two- and three-player scenarios indicate that, when the information passed between subsystems is sufficiently linear, the two scenarios converge in statistically indifferent number of iterations, but additional “complete” information does reduce variability in the number of iterations. The Modified Game Theoretic approach converges to a smaller region of the Pareto set compared to MDO, but does so without a system facilitator. Finally, a traditional Game Theoretic approach converges to a limit cycle rather than a fixed point for the given initial design. There may also be a region of attraction for convergence for a traditional Game Theoretic approach.
Improving Multi-Response Metamodels With Upper/Lower Bound Information Using Multi-Stage, Non-Stationary Covariance Functions
Authors: Romero David A. , Amon Cristina H. , Finger Susan
Published: March 2011

Metamodels have been proposed in the literature to reduce the time and resources devoted to design space exploration, to learn about design trade-offs, and to find the best solution to the design problem in the context of simulation-based design and optimization. In previous work in engineering design based on multiple performance criteria, we have proposed the use of Multi-response Bayesian Surrogate Models (MR-BSM) to model several response variables simultaneously, instead of modeling them independently. By doing so, it is expected that the correlation among the response variables can be used to achieve better models with smaller data sets. In this work, we extend the capabilities of MR-BSM by developing a multistage formulation with non-stationary covariance functions. This formulation for multi-response metamodeling in successive stages of experimental design, data acquisition and model fitting, enables the integration of different sources of information about system responses, with different levels of accuracy, into a single, global model of the system. The feasibility of the proposed formulation is demonstrated with an example in which two test functions are jointly approximated in two stages. In addition, we demonstrate the potential of the methodology to take advantage of a priori information, expressed as upper and lower bounds on the responses, to improve the accuracy of the metamodels. Results show that the use of bound information can result in order-of-magnitude improvements in metamodel accuracy.
An Importance Decision Method of Customers’ Demands for Highly Public Service
Authors: Yamamoto Satoshi , Kimita Koji , Shimomura Yoshiki
Published: March 2011

General service designs focus on specific customers. However, because of the diversity of customer demands, it is difficult to design a public service that addresses the demands of all customers. To achieve maximum customer satisfaction, it is imperative to summarize the demands of various customers and design a service by considering customers belonging to different categories. This study aims at realizing a service design by considering different customer groups. In particular, we propose a method that enables service design by considering groups of various customers and minimizing customer dissatisfaction by adopting a group-decision-making approach [1–4].
A Method for Supporting Service Design Based on Multiple Domain Knowledge
Authors: Oki Kazuhiro , Watanabe Kentaro , Chiba Ryosuke , Shimomura Yoshiki
Published: March 2011

Recently, it has become increasingly important to provide customers with highly creative services to attain differentiation from competing firms. Fulfilling customer requirements with such creative service contents is an effective way to differentiate a firm’s services from those of its competitors. However, there have been few studies that directly support the creation of new service contents, e.g., service design support using information-processing technology for knowledge by the computer. It is valid for service providers to acquire creative service design solutions that fulfill customer requirements. In this paper, we propose a support method to fulfill customer requirements for a target service by using the functions of another type of service. This method supports the acquisition of new service design solutions on the basis of the similarity with the customer requirements or functions of different services. The proposed method is verified by applying it to an existing service case.
Stability Analysis of Electrostatically Actuated Resonators With Delayed Feedback Controller
Authors: Alsaleem Fadi , Younis Mohammad I.
Published: March 2011

In this work we investigate the stability of parallel-plate electrostatic MEMS resonators using a delayed feedback controller. Two case studies are investigated: a capacitive sensor made of cantilever beams with a proof mass at their tip and a clamped-clamped microbeam. Dover-cliff integrity curves and basin-of-attraction analysis are used for the stability assessment of the frequency response of the resonators for several scenarios of positive and negative gain in the controller. It is found that, in the case of a positive gain, a velocity or a displacement feedback controller can be used to effectively enhance the stability of the resonators. This is confirmed by an increase in the area of the safe basin of attraction and in shifting the Dover-cliff curve upward. On the other hand, it is shown that a negative gain can significantly weaken the stability of the resonators. This can be of useful use in MEMS for actuation applications, such as in the case of capacitive switches, to lower the activation voltage of these devices and to ensure their trigger under all initial conditions.
A Free Form Robotic Grinding System: A Mathematical Model and an Actual System
Authors: Wu Shuihua , Kazerounian Kazem , Gan Zhongxue , Sun Yunquan
Published: March 2011

This paper presents a robotic grinding system for work pieces with free-form geometries. A mathematical model representing the kinematics and dynamics of the system is built in the first part of the paper. Offline programming, calibration and a novel method for robotic error compensation are utilized to accurately generate the robotic grinding path. Models of the robot, the grinder and the grinding process are integrated to obtain the dynamics of the system. In the second part of the paper, an actual system is presented, with experiments done to verify the kinematic accuracy of the system. A controller based on the target tracking theory is designed to extend the system’s capability of material removal control, the effectiveness of which is shown by the simulation results. In the future, the target-tracking control strategy will be integrated with the actual system to develop a robotic grinding system capable of material removal control for free-form work pieces.
Nonlinear Modeling of a Rigid Rotor Supported on Rolling Element Bearings With Localized Defects
Authors: Kappaganthu Karthik , Nataraj C.
Published: March 2011

In this paper a nonlinear model for defects in rolling element bearings is developed. Detailed nonlinear models are useful to detect, estimate and predict failure in rotating machines. Also, accurate modeling of the defect provides parameters that can be estimated to determine the health of the machine. In this paper the rotor-bearing system is modeled as a rigid rotor and the defects are modeled as pits in the bearing race. Unlike the previous models, the motion of the rolling element thorough the defect is not modeled as a predetermined function; instead, it is dynamically determined since it depends on the clearance and the position of the shaft. Using this nonlinear model, the motion of the shaft is simulated and the effect of the rolling element passing through the defect is studied. The effect of shaft parameters and the defect parameters on the precision of the shaft and the overall performance of the system is studied. Finally, suitable measures for health monitoring and defect tracking are suggested.
Springless Vibration Energy Harvesters
Authors: Mahmoud Mohamed A. E. , Abdel-Rahman Eihab M. , Mansour Raafat R. , El-Saadany Ehab F.
Published: March 2011

A novel vibration energy harvester (VEH) architecture is developed to eliminate the need for restoring force elements (springs) in the VEH. The architecture can realize VEHs with arbitrarily low center frequency. Two prototypes were fabricated and tested to demonstrate the feasibility of this architecture. The center frequency of the first prototype was found to be 2 Hz demonstrating low frequency operation. The second prototype improve the performance by five times at much smaller footprint using thin film fabrication process and precision alignment.
Polymer MEMS for Measuring Single Cell Forces
Authors: Ferrell Nicholas , Woodard James , Gallego-Perez Daniel , Higuita-Castro Natalia , Hansford Derek
Published: March 2011

We have developed a polymer MEMS sensor for measuring mechanical forces generated by single adherent cells. Mechanical forces are known to play a role in cell regulation, and measuring these forces is an important step in understanding cellular mechanotransduction. The sensor consists of four polystyrene microcantilever beams with cell adhesion pads at each end. Finite element analysis was used to guide the design of a compound cantilever to allow measurement of forces in multiple directions. The device was evaluated by measuring forces generated by WS-1 human skin fibroblasts. A single cell was placed on the sensor using a custom micromanipulator. Forces were calculated by optically measuring the deflection of each probe during cell attachment and spreading. Measurements were performed on normal cells and those treated with cytochalasin D to disrupt the actin cytoskeleton. Cytochalasin D treated cells showed a significant decrease in force. This device can be used to evaluate the mechanical response of cells to a variety of chemical, mechanical, and other environmental stimuli.