bluuebunny/crossref_metadata_2025 huggingface dataset:
Usage Coverage Model for Choice Modeling: Principles
Authors: Yannou Bernard , Wang Jiliang , Rianantsoa Ndrianarilala , Hoyle Chris , Drayer Mark , Chen Wei , Alizon Fabrice , Mathieu Jean-Pierre
Published: July 2010

Accurately capturing the future demand for a given product is a hard task in today’s new product development initiatives. As customers become more market-savvy and markets continue fragment, current demand models could greatly benefit from exploiting the rich contextual information that exists in customers’ product usage. As such, we propose a Usage Coverage Model (UCM) as a more thorough means to quantify and capture customer demand by utilizing factors of usage context in order to inform an integrated engineering design and choice modeling approach. We start by presenting the principles of the UCM model: terms, definitions, variable classes and relation classes so as to obtain a common usage language. The usage model exhibits the ability to differentiate between individuals’ product performance experiences. With Discrete Choice Analysis, individuals’ performance with a given product is compared against that of competitive products, capturing individual customers’ choice behavior and thereby creating an effective model of product demand. As a demonstration of our methods, we apply our model in a case study regarding the general task of cutting a wood board with a jigsaw tool. We conclude by presenting the scope of future work for the case study and the contribution of the entire current and future work to the field as a whole.
Direct Simulation Based Model-Predictive Control of Flow Maldistribution in Parallel Microchannels
Authors: Martin Mathieu , Patton Chris , Schmitt John , Apte Sourabh V.
Published: July 2010

The goal of this investigation is to develop a simulation-based control strategy to eliminate flow-maldistribution in parallel microchannels. An accurate simulation of fluid flow through parallel microchannels is achieved by utilizing a fictitious domain representation of immersed objects, such as microvalves and bubbles. System identification techniques are employed to produce a lower dimensional model that captures the essential dynamics of the full nonlinear flow, in terms of a relationship between the valve angles and the exit flow rate for each channel. The resulting linear model is incorporated into a model predictive control scheme to identify flow maldistribution from exit flow velocities and prescribe actuation of channel valves to effectively redistribute the flow. Flow simulations in a three parallel microchannel geometry including bubbles illustrates the effectiveness of the control design, which quickly and efficiently varies channel valves to remove the bubble and equalize the flow rates in each channel.
Incorporation of Passive Wing Folding in Flapping Wing Miniature Air Vehicles
Authors: Mueller Dominik , Gerdes John W. , Gupta Satyandra K.
Published: July 2010

Flapping wing motion produces positive lift in the down stroke and negative lift in the upstroke under zero forward velocity. Large birds frequently exhibit flight behavior where their wings are folded during the upstroke, thus lowering the air resistance as the wing is moved upwards. The result is reduced magnitude of negative lift produced during the upstroke, relative to the positive lift produced in the down stroke, where the wings are unfolded and the area is increased. We expect that by incorporating this style of upstroke wing folding into miniature air vehicle (MAV) platforms, beneficial flight properties would arise. Specifically, a portion of the wings’ overall lift will be generated by upstroke folding and downstroke unfolding, even at zero forward velocity. Such a capability will reduce the reliance on aerodynamic lift produced due to the forward motion of the MAV. This in turn would reduce the minimum flight-sustaining forward velocity and thus enhance MAV maneuverability by allowing for a reduced turning radius. Incorporating wing folding into a miniature air vehicle platform presents a unique challenge due to strict weight constraints present at small sizes. Using actuators to accomplish folding actively is not feasible due to the added weight of the actuators and the need for an on-board control system to synchronize the folding with the wing flapping motion. Therefore, the folding motion must be accomplished passively, since this is currently the only viable option in miniature MAVs. We have developed a passive, spatially distributed, one-way folding mechanism. This mechanism has been incorporated into a flying MAV testbed, and has successfully shown that the flapping wing MAV with folding wings is capable of flying at reduced forward velocity, while maintaining the payload carrying capacity.
Articulated Four Axis Microrobot
Authors: Murthy Rakesh , Das Aditya N.
Published: July 2010

The picture shows a unique MEMS robot. It is highly dextrous with our degrees of freedom (two in-plane and two out-of-plane) and has the largest work volume of 50μm × 50μm × 75 μm amongst MEMS based positioners. The robot incorporates novel cable based transmission systems to couple in-plane actuators with out of plane bi-directional flexure joints. Constructed out of Deep Reactive Ion Etching and microassembly, this robot is designed to transmit upto 200mN of force along all four axes, precise to ten’s of nanometers and configured to carry a variety of end-effectors such as Atomic Force Microscope probe tip arrays and microgrippers. The microrobot presents the dawn of next generation in top down manipulation systems.
Dynamic Modeling and Analysis of a Planetary Gear Involving Tooth Wedging and Bearing Clearance Nonlinearity
Authors: Guo Yi , Parker Robert G.
Published: July 2010

Tooth wedging occurs when a gear tooth comes into contact on the drive-side and back-side simultaneously. Tooth wedging risks bearing failures from elevated forces. This work studies the nonlinear tooth wedging behavior and its correlation with planet bearing forces by analyzing the dynamic response of an example planetary gear based on a real application of a wind turbine geartrain. The two-dimensional lumped-parameter model [1] is extended to include tooth separation, back-side contact, tooth wedging, and bearing clearances. The simulation results show significant impact of tooth wedging on planet bearing forces for a wide range of operating speeds. To develop a physical understanding of the tooth wedging mechanism, connections between planet bearing forces and tooth forces are studied by investigating physical forces and displacements acting throughout the planetary gear. A method to predict tooth wedging based on geometric interactions is developed and verified. The major causes of tooth wedging relate directly to translational vibrations caused by gravity forces and the presence of clearance-type nonlinearities in the form of backlash and bearing clearance.
Optimal Plug-in Hybrid Electric Vehicle Design and Allocation for Diverse Charging Patterns
Authors: Kaushal Nikhil , Shiau Ching-Shin Norman , Michalek Jeremy J.
Published: July 2010

Plug-in hybrid electric vehicle (PHEVs) technology has the potential to address economic, environmental, and national security concerns in the United States by reducing operating cost, greenhouse gas (GHG) emissions and petroleum consumption. However, the net implications of PHEVs depend critically on the distances they are driven between charges: Urban drivers with short commutes who can charge frequently may benefit economically from PHEVs while also reducing fuel consumption and GHG emissions, but drivers who cannot charge frequently are unlikely to make up the cost of large PHEV battery packs with future fuel cost savings. We construct an optimization model to determine the optimal PHEV design and optimal allocation of PHEVs, hybrid-electric vehicles (HEVs) and conventional vehicles (CVs) to drivers in order to minimize net cost, fuel consumption, and GHG emissions. We use data from the 2001 National Household Transportation Survey to estimate the distribution of distance driven per day across vehicles. We find that (1) minimum fuel consumption is achieved by assigning large capacity PHEVs to all drivers; (2) minimum cost is achieved by assigning small capacity PHEVs to all drivers; and (3) minimum greenhouse gas emissions is achieved by assigning medium-capacity PHEVs to drivers who can charge frequently and large-capacity PHEVs to drivers who charge less frequently.
The Effect of Shape and Distribution of Perforations on Squeeze-Film Damping in Parallel Plate Capacitors
Authors: Cui Weili , Miles Ronald N. , Homentcovsci Dorel
Published: July 2010

The effect of the shape and distribution of perforations in parallel plate capacitive MEMS devices on squeeze-film damping is presented. The squeeze film effect is the most important damping effect on the dynamic behavior of most MEMS devices that employ capacitive sensing and actuation, which typically employ narrow air gaps between planar moving surfaces [1, 2]. The stationary plate of a capacitive device is often perforated to reduce the damping and sensor noise and improve the frequency response. The formula for determining the total viscous damping in the gap contains a coefficient Cp that is associated with the geometry and distribution of the holes on the stationary plate. In this study, the coefficient Cp is determined using the finite element method using ANSYS by analogy with heat conduction in a solid with internal heat generation. Round, elliptical, rectangular, and oval holes that are distributed either aligned or offset are analyzed and compared. It is shown that the surface fraction occupied by the perforations is not the only factor that determines Cp. Both the shape and distribution strongly affect the damping coefficient [3, 4]. By using elongated perforations that are properly distributed, the squeeze film damping could be minimized with the minimum amount of perforation. The analysis performed in this work is quite general being applicable to a very large spectrum of frequencies and to various fluids in capacitive sensors. These results can facilitate the design of mechanical structures that utilize capacitive sensing and actuation, such as accelerometers, optical switches, micro-torsion mirrors, resonators, microphones, etc.
Life Cycle Cost Modeling of Hybrid Vehicles During Early Product Architecture Development
Authors: Gorbea Carlos , Fricke Ernst , Lindemann Udo
Published: July 2010

Understanding the factors that affect life cycle costs in the earliest stages of product development bring valuable insights for vehicle architecture decision making. This study presents a life cycle costing model used to compare hybrid electric vehicle architectures with varying levels of electrification to a reference conventional car. The work presented highlights the importance of considering total costs of ownership (COO) and operation alongside manufacturing costs in making strategic business decisions. Results from the life cycle cost model scenarios set for 2015–2024 show that car architectures with increased electric range capability allow for significant customer fuel cost savings. These savings can offset increased manufacturing costs within the first three years of ownership based on US Energy Information Agency (EIA) current fuel and electricity pricing forecasts. If fuel prices or annual vehicle use remain low, electrification becomes less attractive as payback periods are extended beyond 10 years time. Regardless of future energy pricing scenarios, the fixed costs of vehicle ownership remain the largest costs to the end user. Manufacturers can use this information to their advantage in creating new business models and designing cars that deliver increased value to the end customer. Because electrification significantly reduces CO2 tailpipe emissions, government incentives and taxing schemes are expected to play a positive roll in offsetting a large part of the additional manufacturing costs. Finally, optimization methods are used to determine sensitivities of variables that affect total cost of ownership. Of these variables the user’s city/highway driving profiles and the price of fuel/Electricity have the greatest sensitivity to cost of ownership.
Theoretical Modeling and Experimental Validation of Fluid-Loaded Micro Rectangular Plates
Authors: Wu Zhangming , Wright Mike T. , Ma Xianghong
Published: July 2010

This paper presents a theoretical model on the vibration analysis of micro scale fluid-loaded rectangular isotropic plates, based on the Lamb’s assumption of fluid-structure interaction and the Rayleigh-Ritz energy method. An analytical solution for this model is proposed, which can be applied to most cases of boundary conditions. The dynamical experimental data of a series of microfabricated silicon plates are obtained using a base-excitation dynamic testing facility. The natural frequencies and mode shapes in the experimental results are in good agreement with the theoretical simulations for the lower order modes. The presented theoretical and experimental investigations on the vibration characteristics of the micro scale plates are of particular interest in the design of microplate based biosensing devices.
A Study of the Mobility of a Family of 3-DOF Parallel Manipulators via Screw Theory
Authors: Rodriguez-Leal Ernesto , Dai Jian S. , Pennock Gordon R.
Published: July 2010

This paper investigates the mobility of a family of 3-DOF parallel manipulators using screw theory. Based on the 3-PSP, 3-PPS and 3-PCU manipulators and a new 3-CUP parallel manipulator, the paper obtains the branch motion-screws for these architectures and determines the sets of platform constraint-screws. The constraints are identified to be the forces acting on the S and U joints fixed in the platform and the couples acting about an axis perpendicular to the base. The mobility of a manipulator platform is thus obtained by determining the reciprocal screws to the platform constraint screw sets and the platforms are identified to have three instantaneous independent degrees of freedom which are: (i) a translation along an axis perpendicular to the base; and (ii) two rotations about two skew axes.
MEMS Nanoinjector for Injecting Foreign DNA Into Living Cells
Authors: Aten Quentin
Published: July 2010

The nanoinjector is a MEMS device that has been successfully used to inject foreign genetic material into fertilized mouse egg cells (zygotes). This scanning electron micrograph shows a nanoinjector grasping a 100 μm diameter latex sphere. The sphere is roughly the size of a mouse zygote, and it can withstand the harsh environment in the electron microscope better than a mouse zygote. The nanoinjector’s two constraining mechanisms (at left and top-right) and lance mechanism (bottom right) are fabricated from two planar layers of polysilicon through MEMSCAP’s polysilicon Multi-User MEMS Processes (polyMUMPs)
Facets and Fissures of a Fractured SOI Wafer
Authors: Aten Quentin
Published: July 2010

This scanning electron micrograph shows a cross section of a cleaved silicon-on-insulator (SOI) wafter. The wafer cleave passed through a partially released device that included the array of etch release holes visible in this image. The patterned monocrystalline silicon layer had a different crystalline orientation than the much thicker monocrystalline silicon substrate. When the wafer was cleaved, substrate silicon fractured along a single crystalline plane, leaving a flat, smooth surface. The patterned layer did not share this crystalline plane, and fractured in many directions resulting in an irregular, multi-faceted surface.
Closed Loop Estimator-Controller Synthesis for a Two-Zone Controlled Auto-Ignition Engine Model
Authors: Tandra Varun , Srivastava Nilabh
Published: July 2010

This paper outlines the controller development for a physics-based two-zone thermo kinetic model of HCCI/CAI engine presented in the previous work. The model accounted for both temperature and concentration inhomogeneities in the cylinder, which ultimately resulted in better prediction of the combustion parameters. The discrete nonlinear model is linearized about an operating point and the resulting linearized model is used to create an effective tracking controller. The model inputs include the variable valve timings needed to effectively control peak pressure, ignition timing and exhaust temperature. Since some of the model states cannot be monitored under transient conditions, an observer was developed to estimate the states. Two controller-observer models: controller-current observer and controller-predictor observer were designed and simulated using the same engine model. A significant difference was observed between the performances of these two models. Simulation results showed that linear controller can drastically enhance the control of combustion phasing, thereby making the control of HCCI engines practical.
Tensionability of an Arbitrary Two-Link Multibody
Authors: Rezazadeh Siavash , Behzadipour Saeed
Published: July 2010

The main problem in cable-driven mechanisms is their tensionability, i.e. maintaining positive tension in all cables against any external load. Since the advent of these mechanisms, it was known that with one redundant cable, one can guarantee the tensionability of a rigid body driven by cables. However, the problem of tensionability in multibody systems driven by cables has remained almost intact. In a previous work by the authors, some necessary conditions on the number of cables and their possible distributions for tensionability of a general multibody were found. However, unlike the rigid body case, the sufficiency of these conditions for the tensionability of a multibody cannot be easily guaranteed. In this paper, we find the necessary and sufficient conditions for the tensionability of an arbitrary two-link multibody. Our approach investigates the equilibrium of such systems first by assuming that the cables can apply force in both directions (pull and push). Then, unidirectional force characteristic of the cables is incorporated and the associated conditions on the cables and their distributions are found. The heart of the method is based on a matrix called dependency matrix which carries the equilibrium properties of the system in a more compact form. Also, it has relatively clear connections to the geometry of the system which makes it easy to use.
Entropic Method for Sequencing Discrete Design Decisions
Authors: Sen Chiradeep , Ameri Farhad , Summers Joshua D.
Published: July 2010

Early stages of engineering design processes are characterized by high levels of uncertainty due to incomplete knowledge. As the design progresses, additional information is externally added or internally generated within the design process. As a result, the design solution becomes increasingly well-defined and the uncertainty of the problem reduces, diminishing to zero at the end of the process when the design is fully defined. In this research a measure of uncertainty is proposed for a class of engineering design problems called discrete design problems. Previously, three components of complexity in engineering design, namely, size, coupling and solvability, were identified. In this research uncertainty is measured in terms of the number of design variables (size) and the dependency between the variables (coupling). The solvability of each variable is assumed to be uniform for the sake of simplicity. The dependency between two variables is measured as the effect of a decision made on one variable on the solution options available to the other variable. A measure of uncertainty is developed based on this premise, and applied to an example problem to monitor uncertainty reduction through the design process. Results are used to identify and compare three task-sequencing strategies in engineering design.
Varying Lifecycle Lengths Within a Portfolio for Product Take-Back
Authors: Zhao Yuan , Pandey Vijitashwa , Kim Harrison , Thurston Deborah
Published: July 2010

Product take back and reuse is sometimes at odds with the rapidly evolving desires of some customers. For other customers, the environmental benefits of reuse more than compensate for minor drawbacks. “Selling a service” (rather than a product) through leasing enables the manufacturer to control the timing and quality of product take-back, but current methods assume a fixed leasing period. What is needed is a method for fine-tuning the time span of the customer’s life cycle in order to provide each market segment the combination of features it most desires. This paper presents a new method for performing long range product planning so that the manufacturer can determine optimal take-back times, end-of-life design decisions, and number of lifecycles. The method first determines a Pareto optimal frontier over price, environmental impact and reliability using a genetic algorithm. Then, a multiattribute utility function is employed to maximize utility across different segments of the market, and also across different lifecycles within each segment. The proposed methodology is illustrated through an example involving personal computers.
Towards Individual Innovation Capability: The Assessment of Idea Generating Methods and Creativity in a Capstone Design Course
Authors: Berglund Anders , Ritze´n Sofia
Published: July 2010

Innovation is per se based not only on the individual problem solving, but the process from new ideas to commercialization of new products. However, in a time with rapid technology shifts and frequently altered customer requirements, creativity and more precisely the lack of useful new ideas surfacing is viewed as problematic by companies. Ways of involving creativity has been to apply idea generating (IG) methods for identification of creativity sources. This paper consists of a combined theoretical and empirical approach which aims at studying existing tests and proposing suitable creative methods to be used in higher engineering education. The authors work with an extensive capstone design course in Integrated Product Development that emphasizes systematic and parallel approaches to product development. In contrast to traditional modes and styles of teaching that make few attempts to encourage students to pursue a variety of IG methods the capstone design course in integrated product development puts a large part of the responsibility on the students. In all cases IG and use of creativity methods is a natural ingredient. Thus, students’ self-regulation and insights into how to work with methods and exercises is particularly interesting as this may have an affect on managing their creative skill. Overall possible improvements in students’ creative potential transcend interesting notions on capability to innovate. Thus, this paper’s purpose is to investigate whether creativity as an ingredient of a student’s innovation capability is influenced by using IG methods. And whether the selections made by project groups are aligned to best utilize students’ creative thinking.
Challenges in Incorporating Sustainability Into Product Development: An Exploratory Study
Authors: Athalye S. A. , Govindarajan S. K. , Lopez C. A. , Esterman Marcos , Rothenberg Sandra
Published: July 2010

Despite decades of disaggregated initiatives aimed at improving the well-being and quality of life of its employees, their families, communities and stakeholders, many high-technology firms are still struggling to develop an integrated approach to address the triple bottom line aspects of sustainability. In particular how sustainability is being integrated into the product development process, and the challenges that result, is of interest to this work. A literature review into the role of internal factors of how a firm implements a sustainability strategy revealed that it was too normative to guide the implementation of a corporate sustainability strategy at the level of the product development value chain. Therefore, to better understand how senior and mid-level managers actually implement such a strategy, a case study was conducted at two business divisions of two different large, multinational firms that are relatively early in their development of an integrated sustainability strategy. The findings provide insight into the role of internal factors at the level of a business division as it attempts to incorporate sustainability into its product development value chain.
Right Angle Tetrahedron Chain Externally-Actuated Testbed (RATChET): A Shape-Changing System
Authors: White Paul J. , Thorne Chris E. , Yim Mark
Published: July 2010

Modular robotic systems can form arbitrary shapes that best suit task requirements. Such a system comprised of microscale components could form reconfigurable microstructures or high resolution physical prototypes. This paper presents methods aimed at miniaturization of this programmable matter system towards the millimeter scale or smaller. The Right Angle Tetrahedron Chain Externally-actuated Testbed (RATChET) can be folded into arbitrary 3D shapes. The tetrahedron shaped modules are designed to have limited complexity and employ technologies which can be realized at the microscale. The tools developed to design the module’s compliant mechanism can be used to develop small scale modules in the future. Experiments with centimeter scale modules demonstrate that an external actuator can fold a chain of right angle tetrahedrons into 3D shapes. If given the fold pattern to make a shape, a simulator determines the motion sequence for the 2DOF external actuator to fold that pattern.
Design of Autonomous Foldable Docking Mechanism for Small Space Vehicles
Authors: Wiens Gloria J. , Umsrithong Anake , Miller Shawn , Koka Aneesh , Vitello Travis
Published: July 2010

Over the past decade, small satellites have gained the interest of the space industry as a new and cost effective approach for servicing space assets. To address the special constraints inherent to the component miniaturization required for these satellites, researchers in the Space, Automation and Manufacturing Mechanisms Laboratory (SAMM) are exploring foldable mechanisms and their effectiveness for providing autonomous rendezvous and docking capabilities for small space vehicles. This paper focuses particularly on the design of autonomous docking mechanisms for space vehicles within the small satellite class known as picosatellite (size and mass requirements: 1 kilogram mass within a 10×10×10 centimeter cube). The docking mechanisms deployment scenario is a dual satellite system comprised of two small satellites (a chaser and a target). The chaser has attitude and translational control capability, while the target is a passive satellite having only attitude stabilization capability. This paper will first present a review of the existing docking mechanism technology utilized in space. This is followed by details of a foldable mechanism approach for providing small satellites autonomous docking capabilities. This includes geometric and dynamic analysis conducted in ADAMS software simulations.
Adoption of NPD Process Improvement Concepts in Industry: Status Review of Automotive Suppliers in Turkey—2008
Authors: Yayla Yes¸im , Yildiz Aytac¸ , Okudan Gu¨l E.
Published: July 2010

In this paper, we present our findings of a survey exploring the adoption of the new product development process improvement concepts in the automotive suppliers sector in Turkey. With this investigation, we aim to uncover differences in the way suppliers are adopting new product development (NPD) process improvement concepts. Our results indicate that indeed the adoption of the concepts varies across suppliers, and two important factors explaining, in part, this result are: (1) supplier involvement in design, and (2) the potential branding impact of the part/modules supplied.
Benchmarking Product Development Performance of Manufacturing Companies Using Analytic Network Process: A Field Study
Authors: Akman Gu¨ls¸en , Okudan Gu¨l E.
Published: July 2010

Product development is important more than ever for manufacturing firms. A well-designed performance measurement system can assess the impact of product development on the whole company. Such a system can also be utilized for motivating employees, especially product development staff. Naturally, a set of suitable product development measures can provide valuable information for managing the activities and continuous improvement of the product development process. In this paper, via our literature review, we first establish that “a suitable set of performance measures” to assess product development performance is not readily available. Then, we identified performance criteria for assessing product development process effectiveness based on competitive priorities (cost, quality, flexibility, delivery and innovation) followed by ANP analysis. Finally, using a two tier survey setting, the validity and reliability of the criteria set were ascertained, and field data for its (performance measure set) usage as an assessment tool for product development is demonstrated. The field study was conducted by participation of a sample of manufacturing companies in Turkey.
Analysis of Hybrid Cable-Actuated Parallel Manipulators With a Constraining Leg for Lower-Degree-of-Freedom Operation
Authors: Hassan Mahir , Khajepour Amir
Published: July 2010

This paper presents a kinetostatic analysis of a class of hybrid cable-driven parallel manipulators consisting of cables and a rigid-link serial leg for lower-degree-of-freedom tasks. The serial leg provides the task constraints and the cables provide the required actuation to move the platform in the task space. Having a rigid-link serial leg providing the required constraints for the moving platform in lower-degree-of-freedom applications reduces the number of cables required to support the moving platform in the task space. As a result, the manipulator can be designed with fewer cables and actuators. In order for the manipulator to balance arbitrary applied wrenches, redundant actuation is required. This redundant actuation can be obtained from a redundant actuator mounted on one (or more) serial-leg joint(s). Conditions for analyzing the capability of the redundant actuation to generate cable tension are explained in the paper. A discussion is also given on the optimization of the cable layout and the redundant actuator forces to minimize the tension generated in the cables.
Adaptive-Sparse Polynomial Chaos Expansion for Reliability Analysis and Design of Complex Engineering Systems
Authors: Hu Chao , Youn Byeng D.
Published: July 2010

This paper presents an adaptive-sparse polynomial chaos expansion (adaptive-sparse PCE) method for performing engineering reliability analysis and design. The proposed method leverages three ideas: (i) an adaptive scheme to build sparse PCE with the minimum number of bivariate basis functions, (ii) a new projection method using dimension reduction techniques to effectively compute the expansion coefficients of system responses, and (iii) an integration of copula to handle nonlinear correlation of input random variables. The proposed method thus has three distinct features for reliability analysis and design: (a) no need of response sensitivities, (b) no extra cost to evaluate probabilistic sensitivity for design, and (c) capability to handle a nonlinear correlation. Besides, an error decomposition scheme of the proposed method is presented to help analyze error sources in probability analysis. Several engineering problems are used to demonstrate the effectiveness of the adaptive-sparse PCE method.
Reconciling Distance Metric Methods for Rigid Body Displacements
Authors: Purwar Anurag , Ge Qiaode Jeffrey
Published: July 2010

In the last twenty years, researchers have proposed a few different methods to establish a norm (or, metric) for both planar and spatial rigid body displacements. Desire to meaningfully quantify a displacement composed of rotation and translation stems from a requirement to ascertain “distance” between two given displacements in applications, such as motion approximation and interpolation, mechanism synthesis, collision avoidance, positioning, and robot calibration and control. In this paper, we show that the various seemingly different shape independent norm calculation methods based on approximating displacements with higher dimensional rotations via orthogonal matrices, or polar decomposition (PD) and singular value decomposition (SVD) can be reconciled and unified in the mathematically compact and elegant framework of biquaternions. In the process, we also propose an elegant and fast method for such norm calculations.
Application of Failure Modes and Effects Analysis to Support Product In-Use Information Feedback
Authors: McSorley Grant , Huet Greg , Culley Stephen J. , Fortin Clement
Published: July 2010

Due to their increasing responsibility for the total lifecycle costs associated with their products, manufacturers are investing increasingly more efforts in their reduction. One way in which this can be achieved is through the elimination at the design stage of possible in-service issues. This can be supported through the feedback of product in-use information obtained from testing, prototyping and in-service lifecycle stages towards the earlier stages of the development process. In order to facilitate the feedback of this information to design, the idea of complimentary product structures is introduced. The relationships between these structures provide a link between product information across the various lifecycle stages. The similarities between the product structure and the FMEA structure are also examined. As the FMEA organizes its information on a component basis, it is suggested that it provides an adequate basis for the organization of the product in-use information in order to facilitate its association with the product structure. Based on these ideas, a full framework for the feedback and reuse of product in-use information is described.
Configuration Based Improved Synthesis of Metamorphic Mechanisms
Authors: Li Duanling , Zhang Zhonghai , Dai Jian S. , McCarthy J. Michael
Published: July 2010

Metamorphic mechanisms are a class of mechanisms that change their mobility during motions. The deployable and retractable characteristics of these unique mechanisms generate much interest in further investigating their behaviors and potential applications. This paper investigates the resultant configuration variation based on adjacency matrix operation and an improved approach to mechanism synthesis is proposed by adopting elementary matrix operations on the configuration states so as to avoid some omissions caused by existing methods. The synthesis procedure begins with a final configuration of the mechanism, then enumerates possible combinations of different links and associates added links with the binary inverse operations in the matrix transformations of the configuration states, and finally obtains a synthesis result. An algorithm is presented and the topological symmetry of links is used to reduce the number of mechanisms in the synthesis. Some mechanisms of this kind are illustrated as examples.
Design of a Fuzzy Controller for Independent Control of Front Wheels Steering Angles
Authors: Goodarzi Avesta , Rahiminejad Davood , Esmailzadeh Ebrahim
Published: July 2010

In this study a novel control strategy for independent control of front wheels’ steering angles, using fuzzy logic control, has been developed. For this purpose at first the appropriate vehicle dynamic models have been introduced. A simplified two-degree-of-freedom model is considered as the reference model and then a comprehensive eight-degree-of-freedom model is developed as the simulation tool. In the next step, the comprehensive control system has been designed. The control system based on the yaw rate error of the actual vehicle comparing to the predefined reference model, the actual vehicle side slip angle and also lateral acceleration of the actual vehicle, calculates the correction steering angles of the front inner and outer wheels. Finally, a sophisticated precise numerical simulation is performed. In order to ponder the performance of the proposed controller, an optimal control system as an active steering control (ASC) has been used for comparison. The simulation results show considerable improvement in handling and stability of the vehicle compared to the conventional non-controlled system and also a vehicle equipped with an optimal controller ASC.
Heuristic Machining Process Planning of a Toleranced Handle Based on Graph Inference
Authors: Cheng Kuo-Ming , Tsai Jhy-Cherng
Published: July 2010

This paper investigates the methodology for fast machining process planning that satisfies part tolerancing specifications through the example of a handle. The method first maps each feature of a part into feasible finishing processes that are capable to achieve the specified tolerances and surface requirements associated with the feature. All possible process plans are then developed by expanding preceding processes of each finishing process. A directed graph, with processes as nodes and process sequence as links, is employed to represent the expanded machining processes. Process clusters with same specifications can be further merged and pruned to reduce the computational complexity of the graph. Each possible plan of the merged results is further integrated based on machining sequences. As there are often many feasible plans for machining a part, the qualified plan that satisfies design specifications is achieved by traversal through the graph. The procedure for machining process plan of the handle by such graph-based inference techniques is demonstrated in the paper. The merit of this method is to employ a unified graph model for representing and to reduce the complexity of the process plan efficiently based on inference on the graph.
A Modified Reliability Index Approach for Reliability-Based Design Optimization
Authors: Lin Po Ting , Gea Hae Chang , Jaluria Yogesh
Published: July 2010

RBDO problems have been intensively studied for many decades. Since Hasofer and Lind defined a measure of the second-moment reliability index, many RBDO methods utilizing the concept of reliability index have been introduced as the Reliability Index Approach (RIA). In the RIA, a reliability analysis problem is formulated to find the reliability index for each performance constraint and the solutions are used to evaluate the failure probability. However, the traditional RIA suffers from inefficiency and convergence problems. In this paper, we revisited the definition of the reliability index and revealed the convergence problem in the traditional RIA. Furthermore, a new definition of the reliability index is proposed to correct this problem and a modified Reliability Index Approach based on this definition is developed. Numerical examples using both the traditional RIA and the modified RIA are compared and discussed.
Branch Identification of Planar Two-DOF Seven-Bar Linkages
Authors: Wang Jun , Ting Kwun-Lon , Xue Changyu
Published: July 2010

Mobility identification mainly refers to the problems with the motion continuity and smoothness of a potential design or plan. In any linkage synthesis or robot navigation, it is highly desirable that the ability of any of the numerous design candidates to reach the desired positions in a favorable manner can be determined in a single decisive step automatically rather than through a blind trial or even a physical experiment. Mobility of complex linkages has been one of the most troublesome problems in linkage synthesis and programming and the problem is further complicated with multiple degrees-of-freedom. For multiloop parallel manipulators this paper may represent the first mobility analysis method that can not only decisively and unambiguously rectify motion continuity between discrete positions but also provide clear geometric insight or interpretation regarding the formation of discontinuity. The treatment is based on the principle that the mobility of a multiloop linkage is affected by the mobility of each individual loop as well as the interaction between loops. Since the N-bar rotatability laws govern the mobility of an individual loop, the main mobility issue for multiloop linkages is how the mobility of these loops affects each other. One may find that the concept of joint rotation space (JRS) offers simple and intuitive explanation on how the mobility is affected by the combination of loops. The treatment is very suitable for an automated computer-aided mobility analysis. Examples are employed to demonstrate the proposed method. Continuity is a pivotal issue in linkage mobility analysis. Once the continuity can be rectified, problems with smoothness or singularity, which are discussed in the companion paper [28], can be resolved.
A Generalized Constraint Model for Two-Dimensional Beam Flexures
Authors: Awtar Shorya , Sen Shiladitya
Published: July 2010

To utilize beam flexures in constraint-based flexure mechanism design, it is important to develop a qualitative and quantitative understanding of their constraint characteristics in terms of stiffness and error motions. This paper provides a highly generalized yet accurate closed-form load-displacement model for two-dimensional beam flexures, taking into account the nonlinearities arising from load equilibrium applied in the deformed configuration. In particular, stiffness and error motions are parametrically quantified in terms of elastic, load-stiffening, kinematic, and elastokinematic effects. The proposed beam constraint model incorporates any general loading conditions, boundary conditions, initial curvature, and beam shape. The accuracy and effectiveness of the proposed beam constraint model is verified extensively by non-linear Finite Elements Analysis.
Modeling of Vertically Aligned Carbon Nanotube Composites for Vibration Damping
Authors: Jia J. Y. , Liao W. H.
Published: July 2010

High density aligned multi-walled carbon nanotubes (CNTs) and the CNT/epoxy composite are fabricated. To predict the energy dissipation in composites with vertically aligned multi-walled CNTs, a structural damping model of composite unit cell composed of resin, sheath and nanotube is developed. In this paper, the resin is described as viscoelastic material using Maxwell model. The CNT/epoxy composite is modeled based on the “stick-slip” mechanism, to describe the load transfer behavior between the CNT and its sheath. In order to further study the damping mechanism of the CNT composite, key parameters, such as length, center-to-center distance and critical stress of CNTs that are expected to affect the composite damping performances are studied. The simulation results show that loss factor of the CNT composite with varying parameters is sensitive to the applied stress.
A Text Understanding Interface for Physical System Modeling and Simulation
Authors: Tarkesh Esfahani Ehsan , Sundararajan V.
Published: July 2010

This paper describes a method for using text description as a natural interface to construct models of mechanical systems. The goal is to convert the natural text description from the user to a system of equations that can be used to model and simulate the system. The algorithm of this process consists of three main stages: 1-Component Extraction, 2-Interaction detection and 3-Attribute detection. The description is first parsed to identify and instantiate components. The text is then scanned again to analyze the action verbs to identify component attributes and to detect connections between the components. Finally, numerical values and initial conditions are associated with the attributes. System equations are generated by detecting loops in the device description. The knowledge is gradually built up through progressive scanning and analysis of text. The paper describes the algorithms, presents a detailed example and identifies current assumptions and restrictions.
Two Dimensional Hydro Dynamic and Thermal Modeling of a Turbulent Two Phase Stratified Gas-Liquid Pipe Flow
Authors: Mansoori Z. , Yoosefabadi Z. Tayarani , Saffar-Avval M. , Behzad F. , Ahmadi G.
Published: July 2010

A numerical model for solving a fully developed, turbulent, smooth stratified two-phase gas-liquid flow in pipeline is developed. This model is capable to determine pressure drop and liquid height. In addition wall and interfacial shear stress, flow field and temperature field for both phases could be predicted successfully. The method solves the two dimensional momentum and energy equations for both phases and accounts for the effects of turbulence through the use of high Reynolds k – ε two-equation model of turbulence. The bipolar coordinate system is aided to fit the pipe wall and the interface. Also, grid refinement near the interface and near the pipe wall was used for accurate solution near the boundaries. The predicted data by this method is compared with some available Experimental data as well as one and two dimensional modeling results. It is concluded that a perfect agreement between this model and experimental results could be achieved and the ability of this model for prediction of data is more acceptable than one and some two dimensional models. In conclusion this model could have important application for optimization of transportation rates and estimation of corrosion in pipeline.
Study of Temperature and Velocity Distribution of Rarefied Gas Flow in Micro-Nano Channels
Authors: Ghezel Sofloo Hadi , Shams Alireza , Ebrahimi Reza
Published: July 2010

This paper deals with simulation of transport phenomena in micro and nano pores. The number of cavities and the cavity radius were estimated by using Henry’s law for adsorption of Argon onto ZSM-5 and NaX zeolites. This work showed both of zeolites have pores with average size less than 1 nm. Then with using micro-nano channel assumption instead of micro-nano pores, gas flow and heat transfer were investigated. Subsonic nonideal gas flow and heat transfer for different Knudsen number are investigated numerically using the Direct Simulation Monte Carlo method modified with a consistent Boltzamnn algorithm. The collision rate is also modified based on the Enskog theory for dense gas. It is shown that nonideal gas effect becomes significant when the gas becomes so dense that the ideal gas assumption breaks down. The results also show that the nonideal gas effect is dependent not only on the gas density, but also the channel size. A higher gas density and a smaller channel size lead to a more significant nonideal gas effect. The nonideal gas effect also causes lower skin friction coefficients and different heat transfer flux distributions at the wall surface.
The Practical Capabilities of User-Friendly Interpretations of Hydrodynamic Equations and/or Graphical Images
Authors: Yedidiah S.
Published: July 2010

This paper discusses the physical meanings of certain hydrodynamic expressions. It demonstrates that this knowledge is capable of assisting an engineer in solving even the most enigmatic problems. Also, it demonstrates how this knowledge is capable of helping the CFD-expert in executing more meaningful studies. This paper refers directly only to the design and operation of rotodynamic pumps. However, there exists strong evidence, that the arrived at conclusions may also be valid for other branches of fluids engineering.
Coupling Active and Passive Flow Control Strategies for Simplified Car Models
Authors: Bruneau Charles-Henri , Creuse´ Emmanuel , Depeyras Delphine , Gillie´ron Patrick , Mortazavi Iraj
Published: July 2010

The aim of this work is to control the flow around ground vehicles by active or/and passive strategies. The active control is achieved by steady, pulsed or closed-loop jets located at the back of the simplified car model. The passive control is performed using porous layers between the solid body and the fluid in order to modify the shear forces. Then, the two previous control methods are coupled to improve the drag reduction.