bluuebunny/crossref_metadata_2025 huggingface dataset:
Augmented Books Applied to Engineering: An Attractive Tool for the Student and Useful for Learning
Authors: Marti´n-Gutie´rrez Jorge , Contero Manuel
Published: June 2012

Learning and teaching procedures need to evolve, regarding the high technological profile most students have. The Teacher might consider that in some cases, outdated teaching methods create barriers for students who are used to interaction with modern technological gadgets and computers. Augmented Reality technology emerges as a great potential tool in the teaching environment. Augmented reality (AR) is a cost-effective technology which has the ability to coexist with paper books supplying students with more attractive and didactic contents meaning rebirth of classic textbooks. In this work we present the developed didactic material supported by AR technology for learning sketching, designation and rules of standard mechanical elements. This book has been included in the curriculum of engineering graphics subject of the Mechanical Engineering Degree in a Spanish University for performing a pilot study seeking comparison of academic performance acquired and motivation for study between two groups of students. One group uses AR based material meanwhile the other uses traditional class notes.
Characterization of Five-Pad Tilting-Pad Journal Bearings Using an Original Test-Rig
Authors: Chatterton S. , Pennacchi P. , Vania A. , Tanzi E. , Ricci R.
Published: June 2012

Tilting-pad journal bearings are installed with increased frequency owing to their dynamic stability characteristics in several rotating machine applications, typically in high rotating speed cases. This usually happens for new installations in highspeed compressors or during revamping operations of steam and gas turbines for power generation. The selection from a catalogue, or the design of a new bearing, requires the knowledge of the bearing characteristics such as babbitt metal temperatures, fluid-film thickness, load capacity, stiffness and damping coefficients. Temperature and fluid-film thickness are essential for the safety of the bearing. Babbitt metal is subject to creep at high temperatures, as it happens at high speed operations. On the contrary, at low speed or with high loads, oil-film thickness could be too low, resulting in metal to metal contact. Oil-film dynamic coefficients are largely responsible of the dynamic behaviour and of the stability of the rotor-tilting-pad-bearing system. Therefore, the theoretical evaluation and/or the experimental estimation of these coefficients are mandatory in the design phase. The theoretical evaluation of these coefficients for tilting pad journal bearings is difficult due to their complex geometry, boundary and thermal conditions and turbulent flow, whereas an experimental characterization requires a suitable test rig. The paper describes the test rig designed to this purpose and its unusual configuration with respect to other test rigs available in literature. Some preliminary tests performed for the bearing characterization are also shown.
Improved Architecture Designs for a Low Cost Personal Remote Sensing Platform: Flight Control and Safety
Authors: Coopmans Calvin , Di Long , Jensen Austin , Dennis Aaron A. , Chen YangQuan
Published: June 2012

Remote sensing is a field traditionally dominated by expensive, large-scale operations. This paper presents our efforts to improve our unmanned aircraft (UA) platforms for low-cost personal remote sensing purposes. Safety concerns are first emphasized regarding the local airspace and multiple fail-safe features are shown in the current system. Then the AggieAir unmanned system architecture is briefly described including the Paparazzi UA autopilot, AggieAir JAUS implementation, AggieNav navigation unit and payload integration. Some preliminary flight test results and images acquired using an example thermal IR payload system are also shown. Finally Multi-UAV and heterogeneous platform capabilities are discussed with respect to their applications. Based on our approaches on the new architecture design, personal remote sensing on smaller-scale operations can be more beneficial and common.
The Development of a Facial-Affect Recognition System for Application in Human-Robot Interaction Scenarios
Authors: Schacter David , Wang Christopher , Nejat Goldie , Benhabib Beno
Published: June 2012

This paper presents a non-contact unique automated affect recognition system that identifies human facial expressions and classifies them using Support Vector Regression (SVR) into affective states based on a pleasure-arousal two-dimensional model of affect. By utilizing a continuous two-dimensional model, rather than a traditional discrete categorical model for affect, the proposed system captures complex and ambiguous emotions that are prevalent in real-world scenarios. Our aim is to incorporate the proposed recognition system in robots engaged in human-robot interaction (HRI) scenarios. Namely, the system can be utilized by a robot to recognize, in real-time, spontaneous natural facial expressions of a variety of individuals in response to environmental and interactive stimuli. Preliminary experiments demonstrate the system’s ability to recognize affect from a number of individuals displaying different facial expressions.
Experimental Validation and Updating of the Flexible Multibody Model of a Commercial 3R Planar Manipulator
Authors: Fiorati Stefano , Mucchi Emiliano , Di Gregorio Raffaele , Dalpiaz Giorgio
Published: June 2012

Serial planar manipulators are diffusely used either as stand-alone machines or as part of more complex cells, and many commercial planar manipulators are available on the market. These commercial machines are mainly destined to accomplish low-speed tasks, and they are designed by taking into account their flexibility at most in the joints. Unfortunately, there are particular installation conditions in which even low-speed tasks can generate low-frequency vibrations that highly interfere with the task. This aspect is highlighted here with reference to a commercial 3R planar manipulator, and how to manage this problem is explained. In this sight, a flexible multibody model is developed where the flexibility of the frame, the manipulator is fixed to, is modeled over the flexibility of the joints, that is introduced as lumped stiffness. In particular, the flexible frame is included in the model by using a Component Mode Synthesis methodology, in which only the natural modes of vibration and the static constrain modes are accounted. The model is validated through an experimental campaign. The experimental tests consist of several modal analyses, together with acceleration and laser Doppler measurements in operational conditions. This methodology allows to provide a model which takes into account the installation conditions, and gives a tool for studying ad-hoc solutions which prevent the occurrence of low-frequency vibrations.
Direct NC Path Generation: From Discrete Points to Continuous Spline Paths
Authors: Liu Yu , Xia Songtao , Qian Xiaoping
Published: June 2012

Spline paths in NC machining are advantageous over linear and circular paths due to their smoothness and compact representation, thus are highly desirable in high-speed machining where frequent change of tool position and orientation may lead to inefficient machining, tool wear and chatter. This paper presents an approach for calculating spline NC paths directly from discrete points with controlled accuracy. Part geometry is represented by discrete points via an implicit point set surface (PSS). Cutter location (CL) points are generated directly from implicit part surfaces and interpolated by B-spline curves. A computing procedure for calculating maximum scallop height is given. The procedure is general and suitable for part surfaces in various surface representations provided that the closest distance from a point to the part surface can be calculated. Our results affirm that the proposed approach can produce high-quality B-spline NC paths directly from discrete points. The resulting spline paths make it possible for directly importing discrete points into CNC machines for high-speed machining.
Fine-Tuning Geometrically Constrained Planar Motions
Authors: Zhao Ping , Ge Q. J. , Gao Feng , Su Hai-Jun
Published: June 2012

This paper presents a method for fine-tuning a geometrically constrained planar motion in the context of motion approximation. It builds on the recent work that seeks to identify and extract point trajectories of an explicitly given planar motion. Once two point trajectories are obtained, the remaining issue is to determine the length of the “coupler link” that connects the two point trajectories such that the resulting motion best approximates the original motion. In this paper, the concept of standard deviation in statistics and probability theory is used to define the “distance” between two planar motions. This distance definition is bi-invariant with respect to the choice of both moving and fixed reference frames. Furthermore, the concept of kinetic energy is also used for combining translation with rotation when calculating the distance between two planar displacements. A simple, direct search method for obtaining the optimum length of the coupler link is presented that minimizes the standard deviation of the motion error in terms of the kinetic energy based distance measure for planar displacements.
Eigenvalue Analysis of Multibody Models of Railroad Vehicles Including Track Flexibility
Authors: Escalona Jose´ L. , Chamorro Rosario , Recuero Antonio M.
Published: June 2012

The stability analysis of railroad vehicles using eigenvalue analysis can provide essential information about the stability of the motion, ride quality or passengers comfort. The system eigenvalues are not in general a vehicle property but a property of a vehicle travelling steadily on a periodic track. Therefore the eigenvalue analysis follows three steps: calculation of steady motion, linearization of the equations of motion and eigenvalue calculation. This paper deals with different numerical methods that can be used for the eigenvalue analysis of multibody models of railroad vehicles that can include deformable tracks. Depending on the degree of nonlinearity of the model, coordinate selection or the coordinate system used for the description of the motion, different methodologies are used in the eigenvalue analysis. A direct eigenvalue analysis is used to analyse the vehicle dynamics from the differential-algebraic equations of motion written in terms of a set of constrained coordinates. In this case not all the obtained eigenvalues are related to the dynamics of the system. As an alternative the equations of motion can be obtained in terms of independent coordinates taking the form of ordinary differential equations. This procedure requires more computations but the interpretation of the results is straightforward.
Singularity Analysis of the 4-RUU Parallel Manipulator Based on Grassmann-Cayley Algebra and Grassmann Geometry
Authors: Amine Semaan , Tale Masouleh Mehdi , Caro Ste´phane , Wenger Philippe , Gosselin Cle´ment
Published: June 2012

This paper deals with the singularity analysis of parallel manipulators with identical limb structures performing Scho¨nflies motions, namely, three independent translations and one rotation about an axis of fixed direction. The study is developed through the singularity analysis of the 4-RUU parallel manipulator. The 6 × 6 Jacobian matrix of such manipulators contains two lines at infinity, namely, two constraint moments, among its six Plu¨cker lines. The Grassmann-Cayley Algebra is used to obtain geometric singularity conditions. However, due to the presence of lines at infinity, the rank deficiency of the Jacobian matrix for the singularity conditions is not easy to grasp. Therefore, a wrench graph representation for some singularity conditions emphasizes the linear dependence of the Plu¨cker lines of the Jacobian matrix and highlights the correspondence between Grassmann-Cayley algebra and Grassmann geometry.
Motion Planning of Uncertain Fully-Actuated Dynamical Systems: A Forward Dynamics Formulation
Authors: Hays Joe , Sandu Adrian , Sandu Corina , Hong Dennis
Published: June 2012

This work presents a novel nonlinear programming based motion planning framework that treats uncertain fully-actuated dynamical systems described by ordinary differential equations. Uncertainty in multibody dynamical systems comes from various sources, such as: system parameters, initial conditions, sensor and actuator noise, and external forcing. Treatment of uncertainty in design is of paramount practical importance because all real-life systems are affected by it; ignoring uncertainty during design may lead to poor robustness and suboptimal performance. System uncertainties are modeled using Generalized Polynomial Chaos and are solved quantitatively using a least-square collocation method. The computational efficiency of this approach enables the inclusion of uncertainty statistics in the nonlinear programming optimization process. As such, new design questions related to uncertain dynamical systems can now be answered through the new framework. Specifically, this work presents the new framework through a forward dynamics formulation where deterministic actuator inputs are prescribed and uncertain state trajectories are quantified. The benefits of the ability to quantify the resulting state uncertainty are illustrated in an effort optimal motion planning case-study of a serial manipulator pick-and-place application. The resulting design determines a feasible effort optimal motion plan—subject to actuator and obstacle avoidance constraints—for all possible systems within the probability space. Variance of the system’s terminal conditions are also minimized in a Pareto optimal sense. The inverse dynamics formulation (using deterministic state trajectories and uncertain actuator inputs) is presented in a companion paper.
Foraging for Inspiration: Understanding and Supporting the Online Information Seeking Practices of Biologically Inspired Designers
Authors: Vattam Swaroop S. , Goel Ashok K.
Published: June 2012

Finding suitable biological systems to emulate is one of the key initial steps in biologically inspired design. Designers often turn to online information environments such as the World Wide Web to seek biological sources of inspiration, which poses its own set of challenges. The focus of our research is to understand and address those challenges. In this paper, we first present an information-processing model of the task of seeking bio-inspiration in online information environments based on our observations of designers engaged in biologically inspired design. Then, we analyze the information foraging behavior of designers that is encapsulated in this model to understand the costs associated with this task. Next, we propose an approach for enhancing information environments to better support the task of seeking bio-inspiration. Our approach augments individual information resources within an information environment with conceptual models to make the task of finding relevant information resources more efficient. Finally, we describe an interactive online information environment called Biologue that realizes this approach.
Principles of Mechanical Design for the Developing World: A Case Study Approach
Authors: Andersen Adam J. , Kim Charles
Published: June 2012

Designing appropriate technology is becoming more prevalent as engineers have begun to focus more of their attention on the developing world. However, many efforts have failed or been relatively unsuccessful due to design processes that do not focus on sustainability. One author has provided a solid framework by outlining mechanical design basic principles including design for simplicity, analysis of load paths, and use of prototypes. Yet these principles were not presented in a way that makes them applicable to sustainable projects in the developing world. In this paper, these three principles are investigated through two design case studies. The goal was to analyze how well these principles apply to the developing world and whether several hypothesized changes would also be useful. With the principles in mind, a bicycle trailer and taxi were designed for an impoverished community in rural Africa. Based on these designs, it was determined that the three principles analyzed apply to the developing world but should be refocused and presented differently in order to be utilized effectively for sustainability.
A Study of the Effectiveness of Empathic Experience Design as a Creativity Technique
Authors: Genco Nicole , Johnson Danny , Ho¨ltta¨-Otto Katja , Seepersad Carolyn Conner
Published: June 2012

The need for innovation in product design is an ongoing challenge. Many methods have been proposed to create more innovative products and to better identify customer needs. In this study we introduce an Empathic Experience Design (EED) method to be used just prior to concept generation to help create more innovative concepts. The EED method exposes the designer to empathic experiences, which are designed to help the designer empathize with customers who use the product under a variety of non-ideal conditions. Separate experiments were conducted at two universities, in which students were asked to develop concepts for a next-generation alarm clock. Subject and control experiments were designed and implemented, and the resulting concepts were analyzed to determine the originality and technical quality of each concept. The subject group concepts, which were developed after participating in the empathic experiences, were compared with the control group concepts, which were developed without empathic experiences. At each university, the subject group concepts demonstrated significantly higher originality, relative to the control group concepts, without any sacrifice in technical quality.
Underactuated Part Alignment System (UPAS) for Industrial Assembly Tasks
Authors: Slaboch Brian J. , Voglewede Philip
Published: June 2012

This paper introduces the Underactuated Part Alignment System (UPAS) as a cost-effective and flexible approach to aligning parts in the vertical plane prior to an industrial robotic assembly task. The advantage of the UPAS is that it utilizes the degrees of freedom (DOFs) of a SCARA (Selective Compliant Assembly Robot Arm) type robot in conjunction with an external fixed post to achieve the desired part alignment. Three path planning techniques will be presented that can be used with the UPAS to achieve the proper part rotation.
Development of Sustainable Indicators for Products and Processes
Authors: Bao Han P. , Bodapati Sundeep
Published: June 2012

Sustainable development is only a lofty goal as long as there is a lack of standard metrics and benchmark values to measure the performance of sustainable development. Measurement of sustainability has been articulated by researchers in several ways, but most definitions are based on the so-called Triple Bottom Line (TBL) approach i.e., with Economic (Profit), Environment (Planet) and Social welfare (People) objectives. Individual measures were proposed by many researchers for these dimensions of sustainability using various indicators. The focus of this paper is on manufacturing processes and products, as opposed to services and organizational entities, it is meant to test the hypothesis that there is a concise subset to the wide range of indicators so far identified in the literature which could be applied to manufacturing processes and products. We wanted to address three issues: 1- What kinds of indicators can be used; 2- How often have they been used or, in other words, how relevant are they? and 3- Are there other indicators which may have been missing? Our primary approach was to look for real case studies in which the authors clearly intended their products to be officially declared as sustainable. All together we found 106 case studies which fit the purpose of our study in the Environmental Product Declaration (E.P.D., http://www.environdec.com). EPD is an organization which provides relevant, verified and comparable information to meet various customers and market needs. The categories of products in EPD range from food and beverage products to textile, wood, chemical, non-metallic mineral, basic metals, fabricated metal, machinery and equipment, and office machinery and computers. Each case study in EPD was carefully assessed with regards to the three issues indicated above, and the final result was the formation of a new set of indicators which will be more suitable for manufacturing processes and products. This new set of indicators, perhaps better described as a filtered set of indicators, was used in a case study to compare the sustainability of a Cathode Ray Tube (C.R.T.) and a Liquid Crystal Display (L.C.D.) desktop computer. Both of these products have been extensively documented by Sony Corporation and the EPA. They provided substantial quantitative data which enhance the validity of our own study. One other tangible result of our study was the determination of a “Sustainable Threshold“ for various products based on the 106 case studies indicated above. We wanted to submit the proposition that an aggregated score determined as indicated in our work can serve as a reliable measure for sustainability.
7-DOF Cable-Driven Humanoid Robotic Arm
Authors: Ding Jun , Williams Robert L.
Published: June 2012

The purpose of this paper is to study a 7-DOF humanoid cable-driven robotic arm, implement kinematics and dynamics analysis, present different cable-driven designs and evaluate their merits and drawbacks. Since this is a redundant mechanism, kinematics optimization is used to avoid joint limits, singularities and obstacles. Cable kinematics analysis studies the relationships between cable length and the end-effector pose. This is a design modified from the literature. Several new designs are compared in pseudostatics analysis of the arm and a favorable design is suggested in terms of motion range and the cable tensions. Linear programming is used to optimize cable tensions. Dynamics analysis shows that the energy consumption of a cable-driven arm is much less than that of traditional motor-driven arm. Cable-driven robots have potential benefits but also some limitations.
Design of an Hydrogen Powered Electrical Race Vehicle
Authors: Galmarini G. , Mastinu G. , Gobbi M. , Mauri M.
Published: June 2012

The construction of a hydrogen powered electrical race vehicle is presented in this paper. This prototype has been developed to be used in the Shell Eco-Marathon competition. The main aim of this event is to reduce the fuel consumption. According to the technical regulations, the minimum space requirement has been estimated on the basis of the driver anthropometric dimensions. A high performance aerodynamic shape has been developed by starting from an axis-symmetric body which has been optimized for reducing the aerodynamic drag while running close to the ground. CFD analysis has been performed to refine the vehicle shape and to reach the final body geometry. With the help of the FEM analysis, a complex CFRP layout of a monocoque chassis has been defined in order to maximize the body stiffness and to reduce the mass. All the subsystems have been optimized both to reduce the resistance of the vehicle and to maximize the powertrain efficiency. Lab tests have been performed to validate the CFD and FEM analysis. The result of this work is the design of a vehicle, optimized in shape, mass and efficiency, to take part at Shell Eco-Marathon competition.
Enterprise Applications Integration Using Environment Based Design (EBD)
Authors: Tan Suo , Bani Milhim Hamzeh K. , Chen Bo , Schiffauerova Andrea , Zeng Yong
Published: June 2012

Organizations tend to depend on their various legacy applications in supporting their business strategies and in achieving goals. The existing legacy applications are often from different vendors. In order for an enterprise to be efficient and cost-effective, their legacy applications should be seamlessly integrated within and beyond the enterprise. Some research work in Enterprise Applications Integration (EAI) technologies analyzed the problem from the technical point of view while others proposed models for business processes integration such as syntactic and semantic integration. In this paper the EAI is considered as a design problem and is analyzed from design point of view. Environment Based Design (EBD) methodology is applied to handle the integration problem by analyzing and clarifying the design requirements to generate appropriate solutions. A case study is provided to show how the EBD can be applied within a company to generate satisfactory EAI solutions with low cost, efficiency and scalability enhancement.
Misuse of Information-Theoretic Dispersion Measures as Design Complexity Metrics
Authors: Shah Jami J. , Runger George
Published: June 2012

Complexity is defined as a quality of an object with many interwoven elements, aspects, details, or attributes that makes the whole object difficult to understand in a collective sense. Many measures of design complexity have been proposed in the literature. Of these the most popular are Information-theoretic metrics, such as Information Content based on Suh’s Axiomatic Theory and Entropy based on Shannon’s Information Theory. In this paper we will show that not only these metrics do not provide common sense measures of complexity, but they also do not possess proper mathematical properties. At best, they are geared towards measuring a designs goodness of fit rather than its complexity. It is hoped that this paper will generate some debate on strongly held beliefs in the design theory community.
Generating of Worm Gears of an Arbitrary Profile
Authors: Nieszporek Tadeusz
Published: June 2012

The helical surfaces of worms are most often formed using rotary tools, disk-type, finger-type, cup-type, or ring-type over the whole profile height. The form of machined surface is determined not only by the geometrical parameters and profile of the tool, but also by the tool type. Due to technological reasons, the tool most often has the axial action surface profile which is rectilinear, and much more rarely circular. The increasingly wide use of modern multi-axial CNC machine tools enable the development of technologies for machining helical surfaces of an arbitrary profile. The tool in this case is a small-diameter ball finger cutter. A worm of an arbitrary profile can, however, be made on a principle similar to that of making complex-shaped mould and dies on CNC milling machines with a small-diameter finger cutter. Worm gear can be generated by the same method. In this technology universal tool, ball finger cutter, can be applied for manufacturing worms and wormwheels.
Semi-Supervised Learning With Co-Training for Data-Driven Prognostics
Authors: Hu Chao , Youn Byeng D. , Kim Taejin
Published: June 2012

Traditional data-driven prognostics often requires a large amount of failure data for the offline training in order to achieve good accuracy for the online prediction. However, in many engineered systems, failure data are fairly expensive and time-consuming to obtain while suspension data are readily available. In such cases, it becomes essentially critical to utilize suspension data, which may carry rich information regarding the degradation trend and help achieve more accurate remaining useful life (RUL) prediction. To this end, this paper proposes a co-training-based data-driven prognostic algorithm, denoted by Coprog, which uses two individual data-driven algorithms with each predicting RULs of suspension units for the other. The confidence of an individual data-driven algorithm in predicting the RUL of a suspension unit is quantified by the extent to which the inclusion of that unit in the training data set reduces the sum square error (SSE) in RUL prediction on the failure units. After a suspension unit is chosen and its RUL is predicted by an individual algorithm, it becomes a virtual failure unit that is added to the training data set. Results obtained from two case studies suggest that Coprog gives more accurate RUL predictions compared to any individual algorithm without the consideration of suspension data and that Coprog can effectively exploit suspension data to improve the accuracy in data-driven prognostics.
Design and Simulation of a Compact Electromagnetic Actuator for the Synchronized Segmentally Interchanging Pulley Transmission System (SSIPTS)
Authors: Wen Peter Baoping , Mashatan Vahid , Zu Jean W.
Published: June 2012

This paper presents a practical approach of FEA modeling and optimization of the design of the compact electromagnetic actuator. This special actuator is designed to perform the gear shifts in the synchronized segmentally interchanging pulley transmission system (SSIPTS.) The geometry and material properties of the actuator, which are confined by the assembling space and running condition of SSIPTS, are parametrically optimized by using FEA package, Comsol Multiphysics. The current density of coil, the geometric parameters of magnet, and the permeability of structural materials are major control variables in the optimization of the novel actuator. The target of the optimization process is to find the maximum electromagnetic force and the minimum mass of the entire device within the available space in the transmission package. The simulation results for the optimized design are presented and further compared with the performance requirements of the actuator.
Mechatronic Design - Still a Considerable Challenge
Authors: Torry-Smith Jonas Mo̸rkeberg , Achiche Sofiane , Mortensen Niels Henrik , Qamar Ahsan , Wikander Jan , During Carl
Published: June 2012

Development of mechatronic products is traditionally carried out by several design experts from different design domains. Performing development of mechatronic products is thus greatly challenging. In order to tackle this, the critical challenges in mechatronics have to be well understood and well supported through applicable methods and tools. This paper aims at identifying the major challenges, by conducting a survey of the most relevant research work in mechatronic design. Solutions proposed in literature are assessed and illustrated through a case study in order to investigate, if the challenges can be handled appropriately by the methods, tools, and mindsets suggested by the mechatronic community. Using a real world mechatronics case, the paper identifies the areas where further research is required, by showing a clear connection between the actual problems faced during the design task, and the nature of the solutions currently available. From the results obtained from this research, one can conclude that although various attempts have been developed to support conceptual design of mechatronics, these attempts are still not sufficient to help in assessing the consequences of selecting between alternative conceptual solutions across multiple domains. We believe that a common language is essential in developing mechatronics, and should be evaluated based on: its capability to represent the desired views effectively, its potential to be understood by engineers from the various domains, and its effect on the efficiency of the development process.
Down Force Control of the Low Velocity Racing Car Using Active Aerodynamic Inverse Wings
Authors: Barari Ahmad , Diba Fereydoon , Esmailzadeh Ebrahim
Published: June 2012

A common denominator in all types of racing cars is the need for more traction and road holding, which is limited in traction to the capability of the dynamics of the vehicle, and its tires. Accurate modeling and formulation of the vehicle behavior helps to determine its cornering limits, road stability and handling. A design solution, based on the properties of an aerodynamic system, is developed to study the dynamic performance of a small size racing car. It is shown that the aerodynamic system increases the capability by algorithmic supply of the desired down-forces. The real-time adjustment of the airfoil combinations requires detailed analysis and formulation of the dynamic properties of the vehicle. Also the aerodynamic properties of the configuration of airfoils’ system should be considered. In this paper, implementation of an active aerodynamics inverted wings is investigated for a low-speed, high-down-force application in a typical Formula racing vehicle and detailed analysis and formulation are presented.
Software for Programming an Industrial Serial Manipulator
Authors: Correa Julio
Published: June 2012

This paper presents the capabilities of a computer program developed to facilitate the teaching and learning of the reverse analysis of robot manipulators. The software presents the results graphically and integrates them with a real device.
Resilience-Driven System Design of Complex Engineered Systems
Authors: Youn Byeng D. , Hu Chao , Wang Pingfeng
Published: June 2012

Most engineered systems are designed with a passive and fixed design capacity and, therefore, may become unreliable in the presence of adverse events. Currently, most engineered systems are designed with system redundancies to ensure required system reliability under adverse events. However, a high level of system redundancy increases a system’s life-cycle cost (LCC). Recently, proactive maintenance decisions have been enabled through the development of prognostics and health management (PHM) methods that detect, diagnose, and predict the effects of adverse events. Capitalizing on PHM technology at an early design stage can transform passively reliable (or vulnerable) systems into adaptively reliable (or resilient) systems while considerably reducing their LCC. In this paper, we propose a resilience-driven system design (RDSD) framework with the goal of designing complex engineered systems with resilience characteristics. This design framework is composed of three hierarchical tasks: (i) the resilience allocation problem (RAP) as a top-level design problem to define a resilience measure as a function of reliability and PHM efficiency in an engineering context, (ii) the system reliability-based design optimization (RBDO) as the first bottom-level design problem for the detailed design of components, and (iii) the system PHM design as the second bottom-level design problem for the detailed design of PHM units. The proposed RDSD framework is demonstrated using a simplified aircraft control actuator design problem resulting in a highly resilient actuator with optimized reliability, PHM efficiency and redundancy for the given parameter settings.
Some Remarks on the Dynamic Behaviour of Integrally Shrouded Blade Rows
Authors: Bachschmid N. , Bistolfi S. , Chatterton S. , Ferrante M. , Pesatori E.
Published: June 2012

Actual trend in steam turbine design is to use blades with integral shrouds, for high pressure and intermediate pressure steam turbine sections, as well as also for the long blades of the low pressure sections. The blades are inserted with their root into the seat on the shaft in such a way that the blades are slightly forced against each other in correspondence of the shrouds. In long blades of low pressure stages the forcing can be obtained by the untwisting of twisted blades due to the effect of the huge centrifugal forces. The dynamic behavior of these blade rows is difficult to predict due to the nonlinear effect of the contact forces and due to friction. Different models for the contact are proposed and compared. The resulting natural frequencies of the blade row as a function of the different nodal diameter mode shapes are highly depending on the assumed models. For avoiding resonant conditions with engine order excitations, the natural frequencies must be calculated with good accuracy. Some of the modes of the blade row, typically for the last stage of the low pressure steam turbine, can couple with some vibration modes of the rotor: flexural vibrations of the shaft couple with 1 nodal diameter mode shape of the row in axial direction and torsional vibrations of the shaft couple with the 0 nodal diameter mode in tangential direction. Therefore analyses of lateral and torsional vibrations of low pressure steam turbine shafts require also an accurate analysis of the blade row vibration modes.
Modeling of Plasticity in Spectral Methods for Fatigue Damage Estimation of Narrowband Random Vibrations
Authors: Rognon Herve , Da Silva Botelho Tony , Tawfiq Imad , Galtier Andre , Bennebach Mohamed
Published: June 2012

In this paper, we present techniques for fatigue damage evaluation using spectral methods and a model taking into account elasto-plastic behaviour. The model is associated with a non linear fatigue law, covering the whole endurance domain (low cycle and high cycle fatigue). It uses Neuber’s method and is valid for limited plasticity. To validate this modeling, we perform a correlation between spectral methods, modified spectral methods and experimental data. We present here, the results obtained in the case of narrowband random vibrations.
A Review of Design for X Methods for Medical Devices: The Introduction of a Design for FDA Approach
Authors: Medina Lourdes A. , Wysk Richard A. , Okudan Kremer Gu¨l E.
Published: June 2012

This paper focuses on the importance of the regulations, in particular the Food and Drug Administration (FDA), in the development of medical devices. The FDA regulates medical devices to assure that these products are safe and effective before their release into the Unites States market. We introduce the concept of Design for FDA (DfFDA) and describe DfFDA guidelines for medical device development. While many researchers describe the regulations in the form of reviews and models, the literature to date has not reported a DfFDA method. Here, DfFDA is proposed as a method to be used in parallel with other DfX methods when applicable. The DfX methods identified include: Design for Validation (DfV), Design for Reliability (DfR), Design for Quality (DfQ), Design for Manufacturing (DfM), Design for Assembly (DfA) and Design for Usability (DfU). This paper also reviews the literature addressing the FDA regulations and DfX methods, and an overview of the FDA regulations is presented. DfFDA is developed to increase awareness about regulatory compliance and promote designers to consider the regulations throughout the development process of medical devices.
A Preliminary Study of Actuation Approaches for Lamina Emergent Mechanisms
Authors: Gollnick Paul S. , Black Justin D. , Savage Emily E. , Bowen Landen A. , Qiu Lifang , Magleby Spencer P. , Howell Larry L.
Published: June 2012

Lamina emergent mechanisms (LEMs) are made from sheet materials and have motion that emerges out of the fabrication plane. LEMs can be more compact, more cost effective, and more easily manufactured than many traditional mechanisms. Single-layer and multi-layer LEM designs could greatly benefit from suitable actuation techniques that are consistent with the advantages of these mechanisms. Bulky actuators may not be good choices for use with LEMs. This paper classifies forces and moments applicable to LEMs, shows how multi-layer LEMs can achieve emergent motion in simplified ways, and studies actuation methods for the macro scale. Shape memory alloys, piezo-electrics, and dielectric elastomers are explored as possible ways of setting LEMs into motion.
Exploring the Effect of Design Education on the Design Cognition of Mechanical Engineering Students
Authors: Williams Christopher B. , Gero John , Lee Yoon , Paretti Marie
Published: June 2012

In this paper, the authors report on progress of a longitudinal study on the impact of design education on students’ design thinking and practice. Using innovations in cognitive science and new methods of protocol analysis, the authors are working with engineering students to characterize their design cognition as they progress through engineering curricula. In this paper, the results from a protocol study of sophomore Mechanical Engineering students are presented. Specifically, data gathered from two experimental sessions (conducted before and after the students’ introductory design course) are analyzed to identify changes in design thinking cognition. Design cognition is determined using protocol analysis with the coding of the protocols based on a general design ontology, namely, the Function-Behavior-Structure (FBS) as a principled coding scheme (as opposed to an ad hoc one). Preliminary results indicate that statistically significant changes in students’ design cognition occur over the course of their sophomore year. The change manifests itself in an increase in focus on the purposes of designs being produced, which is often a precursor to the production a higher quality designs, and an increase in the design processes associated with the introduction of purposes of designs.
Developing Innovative Energy Harvesting Approaches for Infrastructure Health Monitoring Systems
Authors: McEvoy Travis , Dierks Eric , Weaver Jason , Inamdar Sumedh , Zimowski Krystian , Wood Kristin L. , Crawford Richard H. , Jensen Dan
Published: June 2012

Many factors must be addressed when designing infrastructure health monitoring systems. Structures in remote locations or with limited accessibility make the requirements for these systems unique and challenging. For locations where connection to the power grid is difficult or impossible, monitoring system life is severely limited by battery technology. Alternatively, an energy harvesting power supply can make the monitoring system independent of the grid while increasing capabilities and lifetime beyond what is possible with current battery technology. This paper discusses a design and development methodology for developing energy harvesting aspects of a health monitoring system. The system comprises a sensor module that monitors the health of the structure, an on-site processing module that analyzes the data, and a wireless communication module that transmits the data. The method is demonstrated by examples of energy harvesting systems for a bridge monitoring application, using solar, wind, and vibration energy harvesters to provide power to a wireless network, local data processors, and strain gauges. Theoretical feasibility of energy harvesting in these domains has been previously demonstrated. The examples described in this paper validate the feasibility previously calculated as well as illustrate shortcomings in the current technology that inhibit potential implementation. The examples also show areas where innovation is needed to continue to advance the technology of energy harvesting in this application on infrastructure.
Model Transitions and Optimization Problem in Multi-Flexible-Body Modeling of Biopolymers
Authors: Poursina Mohammad , Khan Imad , Anderson Kurt S.
Published: June 2012

This paper presents an efficient algorithm for the simulation of multi-flexible-body systems undergoing discontinuous changes in model definition. The equations governing the dynamics of the transitions from a higher to a lower fidelity model and vice versa are formulated through imposing/removing certain constraints on/from the system. Furthermore, the issue of the non-uniqueness of the results associated with the transition from a lower to a higher fidelity model is dealt with as an optimization problem. This optimization problem is subjected to the satisfaction of the impulse-momentum equations. The divide and conquer algorithm (DCA) is applied to formulate the dynamics of the transition. The DCA formulation in its basic form is time optimal and results in linear and logarithmic complexity when implemented in serial and parallel, respectively. As such, it reduces the computational cost of formulating and solving the optimization problem in the transitions to the finer models. Necessary mathematics for the algorithm implementation is developed and a numerical example is given to validate the method.
Exploring Innovation Opportunities in Energy Harvesting Using Functional Modeling Approaches
Authors: Weaver Jason M. , Wood Kristin L. , Crawford Richard H. , Jensen Dan
Published: June 2012

Energy harvesting is a promising and evolving field of research capable of supplying power to systems in a broad range of applications. Energy harvesting encompasses many distinct technologies, including photovoltaic panels, wind turbines, kinetic motion harvesters, and thermal generators. Each technology utilizes different processes to transform energy from the environment into usable electrical energy. As such, there are many analogous functions and processes that are common or similar across the various domains. To leverage and understand these functions and processes, functional modeling approaches are needed to identify these similarities and functions ripe for innovation in new systems. This paper describes a method for modeling the functional architectures of a sample set of energy harvesters, using a functional common basis from the literature. Vector space analysis is used to identify patterns and correlations in the use of functions across different products and energy-harvesting domains in the sample set. The resulting analysis indicates that systems in the same domain usually have very similar function structures, differing only by the addition or removal of a few driving or supporting functions. Systems in different domains also typically have similar structures, with the substitution of different material and energy flows into the system. A generalized functional model for energy harvesting is described, along with possible design ramifications and key opportunities to innovate. Several recommendations are given for the continued development and improvement of the functional common basis and, more generally, functional modeling methodologies. These include improved standardization and explanation of abstract functions, such as blending with the environment, and of organizational conventions to improve consistency.
A Family of Butterfly Flexural Joints: Q-LITF Pivots
Authors: Pei Xu , Yu Jingjun , Bi Shusheng , Zong Guanghua
Published: June 2012

The Leaf-type Isosceles-Trapezoidal Flexural (LITF) pivot consists of two compliant beams and two rigid-bodies. For a single LITF pivot, the range of motion is small while the center-shift is relatively large. The capability of performance can be improved greatly by the combination of four LITF pivots. Base on the pseudo-rigid-body model (PRBM) of a LITF pivot, a method to construct the Quadri-LITF pivots is presented by regarding a single LITF pivot (or double-LITF pivot) as a the configurable flexure module. Ten types of Q-LITF pivots are synthesized. Compared with the single LIFT pivot, the stroke becomes larger, and stiffness becomes smaller. Four of them have the increased center-shift. The other four have the decreased center-shift. One of the quadruple LITF pivots is selected as the examples to explain the proposed method. The comparison between PRBM and Finite Element Analysis (FEA) result shows the validity and effectiveness of the method.
Nonlinear Thermo-Mechanical Vibration Analysis of Functionally Graded Beams
Authors: Fallah Ali , Firoozbakhsh Keikhosrow , Pasharavesh Abdolreza
Published: June 2012

In this paper, nonlinear thermo-mechanical free vibration analysis of functionally graded (FG) beams investigated. Euler-Bernoulli assumptions together with Von Karman’s strain-displacement relation are employed to derive the nonlinear governing partial differential equation (PDE) of motion. He’s variational method is employed to obtain a simple and efficient approximate closed form solution of the nonlinear governing equation. Comparison between results of the present work and those available in literature shows the accuracy of presented technique. Some new results for the nonlinear natural frequencies of the FG beams such as the effect of vibration amplitude, material inhomogeneity and thermal loading are presented for future references.