bluuebunny/crossref_metadata_2025 huggingface dataset:
Development of a Diagnosis Method of a Gear Tooth Surface by Predicting Laser Beam Reflection
Authors: Tanaka Eiichirou , Kojima Yuta , Yoshimi Hiroki , Okabe Kazunari , Takebe Hitoshi , Wada Satoshi , Nagamura Kazuteru , Ikejo Kiyotaka , Nemoto Ryozo
Published: February 2014

We developed a new diagnostic method by using a laser beam. This method is as follows: A tooth surface is irradiated by the zonal laser beam from an oblique direction, and then the irradiated laser beam line is shifted along the surface of the tooth according to gear rotation. If the damage on the irradiated tooth surface exists, the voltage proportional to laser reflection increases. We developed the method to predict and make the reflection benchmark on the normal condition according to the gear surface. To make the benchmark of the diagnosis, the three dimensional basic-data map (x: irradiated angle, y: irradiated distance, z: reflection intensity) was created by measuring the gear only whose material, heat treatment, and roughness were same as the targeted gear. By using the equations of tooth profile and fillet curves calculated from the specifications of the targeted gear, the distance and angle relations between the laser sensor and the tooth surface can be derived. By using the three dimensional basic-data map, the benchmark can be created. The measured reflection data of the non-damage gear agreed well with the benchmark, therefore we can diagnose the various specification gears, if the targeted gear’s material, heat treatment, and roughness are same. Finally, by using the benchmark which was made by our developed method, we proposed a novel diagnosis method. The procedure of the method is as follows:

1) The benchmark is made from the targeted gear’s specifications.

2) To take into account the fluctuation of the benchmark line influenced by the roughness on the gear surface, normal condition area of the reflected data is defined in the range between −0.05 V and +0.05 V of the benchmark line.

3) The normal condition area and measured data is compared, if the measured data is deviated from the normal condition area, there is defined as the abnormal area possible to be damaged.

To confirm the validity of this diagnosis method, the measured value of the damage area with caliper directly and calculated value from the method as mentioned above. The errors of the area and the location were within 20 %. Therefore, the effectiveness of the method using the benchmark data can be confirmed.
Effective Reverse Engineering of Qualitative Design Knowledge: A Case Study of Aerospace Pylon Design
Authors: Tan Suo , Zeng Yong , Huet Greg , Fortin Clément
Published: February 2014

Global collaboration is now a key for enterprises to rapidly achieve their worldwide successes. During the rapid expansion of their business, many challenges are emerging, e.g., novice training, knowledge transferring, intellectual property (IP) protection. This paper presented an effective approach for gaining new knowledge in a design project through reverse engineering by using Environment Based Design (EBD) methodology. The case study used in this paper was designed to demonstrate how design knowledge can be assimilated by using the proposed approach. A graduate student, without any aerospace design knowledge and experience, was presented with a sentence extracted from a statement of work of a student capstone project in the aerospace engineering department of École Polytechnique de Montréal. Within a month, the graduate student designer was able to deliver a conceptual design solution including product life cycle analysis, with only public resources at his disposal. The results were then evaluated by experts in aerospace who have collectively overseen the project for many years, on how much knowledge the student had assimilated. A comparison, between the student designer and other novice designers from the project, was given thereafter. The assessment turns out promising and inspiring in terms of the knowledge assimilation for a novice within such a short time. In other words, the effectiveness of the presented approach has been validated. This is a feasible attempt to significantly shorten the time and minimize the efforts for novice training and knowledge transferring in education and industry, especially when a firm is expanding their global business.
Validation of the Inverse Dynamic Analysis of Human Gait Using a Forward Dynamics Approach
Authors: Pàmies-Vilà Rosa , Font-Llagunes Josep M.
Published: February 2014

One of the aims of the dynamic analysis of human gait is to know the joint forces and torques that the musculoskeletal system produces during the motion. For this purpose, an 18 segment 3D model with 57 degrees of freedom is implemented. The analysis of a captured motion can be addressed by means of forward or inverse dynamic analyses. In this work, both analyses are computed using multibody dynamics techniques. The forward dynamic analysis is carried out with the aim of simulating the movement of the multibody system using the results of the inverse problem as input data. Since the inverse analysis is solved using a dynamically consistent methodology, the forward dynamic analysis allows us to simulate up to the 90% of the gait cycle without any controller. After that, a proportional derivative (PD) controller is implemented to stabilize the system, which gets to simulate the complete captured motion. Moreover, the dynamic contribution of the controller is really low and the simulated motion is extremely close to the original one. The methodology presented allows us to validate the correctness of the inverse dynamics analysis and it is an intermediate step towards the prediction problem: it requires dynamical consistency too, but the uncertainties involved in the problem are lower than in a predictive approach.
Generative Evolutionary Action Grammar Based Form Exploration
Authors: Soni Sitaram , Khanna Pritee , Tandon Puneet
Published: February 2014

The paper describes a prototype design system based on genetic algorithm to evolve concept designs, which are coded in an action grammar. The action grammar captures the design intents expressed by the designers’ strokes during sketching process. The model is based on the assumption that the strokes made by the designers embody the aesthetic intentions expressed through the product form. The knowledge about the design generation is captured and used by the artificial neural network and genetic algorithms respectively. Principal component analysis s is used for the tacit knowledge extraction in the form of heuristics. The proposed formalism is able to support the design within a family as well creative design. The model shows the promise of a conceptual design support system for the exploration of the form during early stages of the design.
Tolerance Plugin Module in Integrated Design
Authors: Söderberg Rikard , Wärmefjord Kristina , Lindkvist Lars
Published: February 2014

Increased use of recycled material in high-end structural components based on wrought alloys is the goal of the EC project Suplight. The project proposes a framework for multi objective optimization. In this paper, a tolerance plugin module used in this project is described. The tolerance plugin module aims at controlling if the geometrical variation requirements on part level are fulfilled. The variation in the part stems from variation in material and process parameters and the relationship between variation in process and material parameters is estimated using designed computer experiments. Moreover, the tolerance plugin module offers an automatically generated meta-model, based on principal component analysis, for handling part variation that allows for faster Monte Carlo simulations and a format that can be used in variation simulations in succeeding assembly steps. The functionality is illustrated using two cases studies; one for investigation of geometrical part variation due to a stamping process and one for investigation of geometrical part variation due to a sheet metal forming process.
Simulation of Motion Parallax for Monitor-Based Augmented Reality Applications
Authors: Radkowski Rafael , Oliver James
Published: February 2014

The paper presents a method for the simulation of motion parallax for monitor-based Augmented Reality (AR) applications. Motion parallax effects the relative movement between far and close objects: near objects appear moving faster than far objects do. This facilitates the perception of depth, distances, and the structure of geometrically complex objects. Today, industrial AR applications are equipped with monitor-based output devices, e.g., for design reviews. Thus this important depth cue is omitted because all objects appear as one even layer on screen. As a result, the assessment of complex structures becomes more difficult. The method presented in this paper utilizes depth images to create layered images: multiple images in which objects in a video image are split up with respect to their distance too a video camera. Using head tracking, the single layers are relatively moved with respect to the user’s head position. This simulates motion parallax. Virtual objects superimpose the final image to complete the AR scene. The method was prototypically realized, the results show its feasibility.
Synergy Between Normative and Descriptive Design Theory and Methodology
Authors: Behdad Sara , Berg Leif P. , Thurston Deborah , Vance Judy M.
Published: February 2014

The problem this paper addresses is the tension between descriptive and normative approaches to design theory and methodology. Descriptive approaches typically seek to document, formalize and/or automate existing ad hoc design methods, towards the goal of making current best practices available to all. In contrast, normative approaches attempt to improve upon existing design practices, towards a new method for how design should be done. Both approaches have strengths and weaknesses. This paper seeks to resolve some of the tension between the two approaches. It presents a new method for designing a design system that synergistically exploits the strengths while remedying the weaknesses of both normative and descriptive methods. An illustration that employs immersive computing technology (ICT) to remedy some of the cognitive biases that might occur in a normative mathematical model for disassembly planning is presented.
ShapeSift: Suggesting Sustainable Options in Design Reuse From Part Repositories
Authors: Ramanujan Devarajan , Benjamin William , Bernstein William Z. , Elmqvist Niklas , Ramani Karthik
Published: February 2014

ShapeSift is a framework for supporting sustainability-based decision making during selection of similar previous designs from part repositories. Our framework is designed for 3D part repositories that contain metadata pertaining to materials and manufacturing processes as well as the functionality of a given part. To demonstrate the usefulness of the proposed framework we develop an example multi-dimensional visualization that encodes part similarities as well as a calculated environmental sustainability indicator. This visualization is incorporated in a prototype interface that focuses on enhancing the intuitiveness of the exploration process by the use of sketch-based retrieval.
Sustainable Manufacturing Through Lean and Green Approach: Best Practices and Indicators
Authors: Verrier Brunilde , Rose Bertrand , Caillaud Emmanuel
Published: February 2014

To become and remain competitive, companies must adopt evolution strategies. Lean Manufacturing is one such strategy used in several industrial companies. Lean Manufacturing is based on the identification and elimination of waste in various production processes. The originality of our work consists in proposing an approach which adds environmental and social dimensions to the consideration of economic earnings received through Lean actions. Adopting a case studies research methodology, we propose an extended literature review of lean and green paradigms and benchmark the practices of industrial companies in order to measure how Lean and Green actions can be enhanced when used together. We then highlight Lean and Green indicators and the associated best practices through the entire lifecycle corresponding to the maturity level of the company.
Conceptual Design of Schoenflies Motion Generators Based on the Wrench Graph
Authors: Amine Semaan , Nurahmi Latifah , Wenger Philippe , Caro Stéphane
Published: February 2014

The subject of this paper is about the conceptual design of parallel Schoenflies motion generators based on the wrench graph.

By using screw theory and Grassmann geometry, some conditions on both the constraint and the actuation wrench systems are generated for the assembly of limbs of parallel Schoenflies motion generators, i.e., 3T1R parallel manipulators. Those conditions are somehow related to the kinematic singularities of the manipulators. Indeed, the parallel manipulator should not be in a constraint singularity in the starting configuration for a valid architecture, otherwise it cannot perform the required motion pattern. After satisfying the latter condition, the parallel manipulator should not be in an actuation singularity in a general configuration, otherwise the obtained parallel manipulator is permanently singular.

Based on the assembly conditions, six types of wrench graphs are identified and correspond to six typical classes of 3T1R parallel manipulators. The geometric properties of these six classes are highlighted. A simplified expression of the superbracket decomposition is obtained for each class, which allows the determination and the comparison of the singularities of 3T1R parallel manipulators at their conceptual design stage. The methodology also provides new architectures of parallel Schoenflies motion generators based on the classification of wrench graphs and on their singularity conditions.
Wrench Reconfigurability via Attachment Point Design in Mobile Cable Robots
Authors: Zhou Xiaobo , Jun Seung-kook , Krovi Venkat
Published: February 2014

In our previous paper [1], we examined enhancing manipulation capabilities of cable robots by addition of base mobility to the spooling-winches. Base mobility facilitated the regulation of the tension-direction (via active repositioning of the mobile bases) and allowed for better conditioning of the wrench feasible workspace. In this paper, we explore design-modifications on the attachment to the common payload (merging multiple cables, attachment via pulleys) as alternate means to improve quality of the wrench-feasible workspace. Specifically we systematically examine the role played by attachment-modality and location, focusing on the benefits/drawbacks of the ensuing natural mechanical averaging behavior. Further, by using the notion of virtual cable subsystems, we illustrate the subsumption of this case into our previous mobile-cable-robot analysis framework. We seek improvement of the overall tension distribution by utilizing configuration space redundancy to shape the tension null-space. This is implemented computationally within the framework of a Tension Factor optimization problem over the workspace and explored via both simulation and experiments.
Incorporating Social Product Development in Distributed Collaborative Design Education
Authors: Wu Dazhong , Morlock Merlin , Pande Prateek , Rosen David W. , Schaefer Dirk
Published: February 2014

Over the past few years, Social Product Development (SPD) has emerged as a new trend to improve traditional engineering design and product realization processes. SPD involves the concepts of crowdsourcing, mass collaboration, customer co-creation, and most recently cloud-based design and manufacturing. One of the key characteristics of SPD is to apply social computing techniques (e.g., social networking sites and online communities) to support different phases of product realization processes. In line with this trend, our objective is to help our students become familiar with this paradigm shift and learn how to solve engineering design problems in a distributed and collaborative setting. Consequently, we have experimented with introducing some aspects of SPD into one of our graduate level engineering design courses. In this paper, we (1) introduce a SPD process that is implemented in the course, (2) present a case study from one of the design teams, and (3) share our experience and lessons with respect to the implementation of the SPD process.
Video Tracking of Tuohy Needle for an Enhanced Epidural Simulator User Interface
Authors: Vaughan Neil , Dubey Venketesh N. , Wee Michael Y. K. , Isaacs Richard
Published: February 2014

A real time motion tracking image processing system was developed for tracking movement of a Tuohy epidural needle. The aim is to use the tracking system to plot 3D movement and rotation of the Tuohy needle to create an enhanced user interface for an epidural simulator. When the needle is angled on its plane or rotated on transverse plane for paramedian insertion the algorithm calculates these angles. The tracker provides a 5-DOF (Degrees of freedom) input option. The image tracker controls a graphical simulation of needle insertion in which a Tuohy needle can be inserted at any location on the patient’s back. As the needle is moved, the virtual needle is moved to the corresponding location in the simulation giving an intuitive interface without using a keyboard or mouse. The image tracking algorithm works by using colour segmentation image processing with a red colour marker on the needle tip. Tracking of the needle position and needle angulation were possible in excess of 10 frames per second even with changes to lighting. A second device is incorporated which measures the pressure of saline inside the syringe barrel so that the simulation can respond to applied pressure.
A Few Good Reasons to Consider a Beam Finite Element Formulation on the Lie Group SE(3)
Authors: Sonneville Valentin , Brüls Olivier
Published: February 2014

Based on an original interpolation method we develop a beam finite element formulation on the Lie group SE(3) which relies on a mathematically rigorous framework and provides compact notations. We work out the beam kinematics in the SE(3) context, the beam deformation measure and obtain the expression of the internal forces using the virtual work principle. The proposed formulation exhibits important features from both the theoretical and numerical points of view. The approach leads to a natural coupling of position and rotation variables and thus differs from classical Timoshenko/Cosserat formulations. We highlight several important properties such as a constant deformation measure over the element, an invariant tangent stiffness matrix under of rigid motions or the absence of shear locking.
A Three-Dimensional Musculoskeletal Driver Model to Study Steering Tasks
Authors: Mehrabi Naser , Razavian Reza Sharif , McPhee John
Published: February 2014

Realistic driver models can play an important role in developing new driver assistance technologies. A realistic driver model can reduce the time-consuming trial and error process of designing and testing products, and thereby reduce the vehicle’s development time and cost. A realistic model should provide both driver path planning and arm motions that are physiologically possible. The interaction between a driver’s hand and steering wheel can influence control performance and steering feel.

The aim of this work is to develop a comprehensive yet practical model of the driver and vehicle. Consequently, a neuro-muscular driver model in conjunction with a high-fidelity vehicle model is developed to learn and understand more about the driver’s performance and preferences, and their effect on vehicle control and stability. This driver model can provide insights into task performance and energy consumption of the driver, including fatigue and co-contraction dynamics of a steering task. In addition, this driver model in conjunction with a high-fidelity steering model can be used to develop new steering technologies such as Electric Power Steering.
Digital Multirange 3Axis MEMS Accelerometer for Railway Applications
Authors: Bassetti M. , Braghin F. , Castelli-Dezza F.
Published: February 2014

In many mechanical applications, measuring accelerations along three orthogonal directions is very important. Especially in railway application a rugged, easy-to-configure and low-noise device could be useful to measure the dynamics of the train. Moreover, freight or passenger trains behave very differently and for homologation purposes accelerometers have to be placed both on the axel-boxes, on the bogies and on the carbody. Therefore, accelerometers with different scales along X,Y and Z axes are required. The present paper presents the design, calibration and test on a freight train of new low cost MEMS accelerometers having sensibility that can be interactively adjusted between ±2g, ±16g and ±40g independently over the three axes. The output of these accelerometers can be set either to digital or to analog (with compensation of the cable length). In the paper the design of the nodes both from the electronic and mechanical points of view is presented. The results of the calibration and of the experimentation are also shown.
Non-Linear and Non-Steady Tire Model Under High-Range Slip Condition
Authors: Afrasiabi Erfan , Braghin Francesco , Sabbioni Edoardo , Scali Vincenzo
Published: February 2014

Based on experimental data, a nonlinear tire model able to predict tire contact forces as a function of slippage, slip angle, camber angle, vertical load, tire bulk and tread temperatures as well as road surface roughness and road temperature has been developed.
Understanding Abstraction in Design: A Comparison of Three Functional Analysis Methods for Product Dissection
Authors: Booth Joran W. , Reid Tahira , Ramani Karthik
Published: February 2014

In design classes, functional analysis is a process that is typically used to assist students with identifying essential functions to aid in the development of their concepts. However, it has been observed that students sometimes struggle with this part of the design process. In this study, a group of 26 students were studied in a 3-level within-subject study (n = 78) to determine which of three common functional analysis approaches (i.e. top-down, energy-flow, and unstructured) was most effective. Participants were asked to dissect a hair dryer, power drill, and NERF pistol and generate function trees describing how these work. Measures of effectiveness include the number of functions generated, the number of errors, the number of levels of abstraction represented in the tree, and the number of unique subsystems and functions identified. No statistical difference between the approaches was found, and there was also no practical difference between the approaches. These results suggest that for novice engineers, there is no difference between methods used. This possibly indicates that for novice engineers, formal methods may not be any more effective than an unstructured approach.
A New Approach for Measuring Terrain Profiles
Authors: Antol Stanislaw , Ryu Kunjin , Furukawa Tomonari
Published: February 2014

This paper presents a new approach for measuring terrain profiles. The proposed approach uses RGB-D sensors to measure terrain surface relative to the vehicle. Since the RGB-D sensor is an area scanner, a feature matching technique called the grid-based feature-to-map matching technique, developed by the authors, matches objects seen in consecutive images and constructs a terrain profile in a global coordinate system. The RGB-D sensor are mounted inside a box to shield natural light and provide consistent LED lighting. As it constructs a terrain profile by matching scanned data regardless of the vehicle movement, the proposed approach is not affected by the vehicle movement as much as conventional techniques and achieves high accuracy. Preliminary experimental work indicates that the proposed approach could measure terrain profiles in sub-centimeter accuracy of all dimensions. The potential applicability of the proposed approach to the maintenance and inspection of railroads has also been demonstrated.
First-Order Reliability Analysis of Vehicle Safety in Highway Horizontal Curves
Authors: Shin Jaekwan , Lee Ikjin
Published: February 2014

This study presents a reliability analysis of vehicle sideslip and rollover in highway horizontal curves, mainly focusing on exit ramps and interchanges. To accurately describe failure modes of a ground vehicle, analytic models for sideslip and rollover are derived considering nonlinear characteristics of vehicle behavior using the commercial software, TruckSim®, with high fidelity. Then, the probability of accident is evaluated using the First-Order Reliability Method (FORM). Furthermore, sensitivity functions of each failure mode are analytically derived to apply FORM.

Numerical studies are conducted using a single-unit truck model. The results show that a truck is more likely to rollover than to slip at dry load. To propose practical application of the study, the reliability analysis for the minimum radius recommended by American Association of State Highway and Transportation Officials (AASHTO) at various speeds and bank angles is conducted. The reliability analysis of current design method shows that the method cannot provide the sufficient margin of safety against both of rollover and sideslip when there are deviations from assumed conditions, especially at low speed of vehicles.
Sampling-Based Approach for Design Optimization in the Presence of Interval Variables
Authors: Yoo David , Lee Ikjin
Published: February 2014

This paper proposes a methodology for sampling-based design optimization in the presence of interval variables. Assuming that an accurate surrogate model is available, the proposed method first searches the worst combination of interval variables for constraints when only interval variables are present or for probabilistic constraints when both interval and random variables are present. Due to the fact that the worst combination of interval variables for probability of failure does not always coincide with that for a performance function, the proposed method directly uses the probability of failure to obtain the worst combination of interval variables when both interval and random variables are present. To calculate sensitivities of constraints and probabilistic constraints with respect to interval variables by the sampling-based method, the behavior of interval variables at the worst case is defined by utilizing the Dirac delta function. Then, Monte Carlo simulation is applied to calculate constraints and probabilistic constraints with the worst combination of interval variables, and their sensitivities. The important merit of the proposed method is that it does not require gradients of performance functions and transformation from X-space to U-space for reliability analysis after the worst combination of interval variables is obtained, thus there is no approximation or restriction in calculating the sensitivities of constraints or probabilistic constraints. Numerical results indicate that the proposed method can search the worst case probability of failure with both efficiency and accuracy and that it can perform design optimization with mixture of random and interval variables by utilizing the worst case probability of failure search.
Multiscale Dynamic Modeling of Flexibility in Myosin V
Authors: Haghshenas-Jaryani Mahdi , Bowling Alan
Published: February 2014

This paper presents a multiscale dynamic model for the simulation and analysis of flexibility in myosin V. A three dimensional (3D) flexible multibody model is developed to mechanically model the biological structure of myosin V. Experimental studies have shown that myosin’s neck domain can be considered as three pairs of tandem elements which can bend at junctures between them. Therefore, each neck is modeled by three rigid bodies connected by flexible spherical joints. One of the most important issues in dynamic modeling of micro-nanoscale sized biological structures, likes DNA and motor proteins, is the long simulation run time due to the disproportionality between physical parameters involved in their dynamics such as mass, drag coefficient, and stiffness. In order to address this issue, the mostly used models, based on the famous overdamped Langevin dynamics, omit the inertial terms in the equations of motion; that leads to a first order model which is inconsistent with the Newton’s second law. However, the proposed model uses the concept of the method of multiple scales (MMS) that brings all terms of the equations of motion into proportion with each other that helps to retain the inertia terms. This keeps consistency of the model with the physical laws and increases time step size of numerical integration from commonly used sub-femto seconds to sub-milli seconds. Therefore, simulation run time will be many orders of magnitude less than ones based on the other approaches. The simulation results obtained by the proposed multiscale model show more realistic dynamic behavior of myosin V in compared with other models.
Virtual Hand Representations to Support Natural Interaction in Immersive Environments
Authors: Rosenberg Meisha , Vance Judy M.
Published: February 2014

Immersive Computing Technology (ICT) offers designers the unique ability to evaluate human interaction with product design concepts through the use of stereo viewing and 3D position tracking. These technologies provide designers with opportunities to create virtual simulations for numerous different applications. In order to support the immersive experience of a virtual simulation, it is necessary to employ interaction techniques that are appropriately mapped to specific tasks. Numerous methods for interacting in various virtual applications have been developed which use wands, game controllers, and haptic devices. However, if the intent of the simulation is to gather information on how a person would interact in an environment, more natural interaction paradigms are needed. The use of 3D hand models coupled with position-tracked gloves provide for intuitive interactions in virtual environments. This paper presents several methods of representing a virtual hand model in the virtual environment to support natural interaction.
Knowledge Base Representation for Axiomatic Design Through Ontologies
Authors: Shi Zhuochen , Mocko Gregory
Published: February 2014

Axiomatic Design has been applied and developed as a tool, offering a scientific basis for design and improving design activities. Axiomatic Design has been used in various fields such as software system design, structure design, and product design. However, several challenges and limitations exist in Axiomatic Design including: the inconsistency in identifying design parameters, existence of coupled design, and multiple groups of functional requirements and design parameters. Aimed at using Axiomatic Design to generate conceptual solutions in engineering design while overcoming its limitations, a formal ontology is developed. The ontology defines functional requirements, design parameters, concepts, components and variables and their relationships. Axioms and rules of Axiomatic Design for the ontology are summarized. The Axiomatic Design ontology is applied to the design of a car seat as an example generating several concepts, and then compared and analyzed multiple groups of the concepts with the help of Axiomatic Design rules. More design ideas can be generated by combining detailed concepts as the higher level possible solutions.
Energy-Momentum Conserving Time Integration of Modally Reduced Flexible Multibody Systems
Authors: Humer Alexander , Gerstmayr Johannes
Published: February 2014

Many conventional time integration schemes frequently adopted in flexible multibody dynamics fail to retain the fundamental conservation laws of energy and momentum of the continuous time domain. Lack of conservation, however, in particular of angular momentum, may give rise to unexpected, unphysical results. To avoid such problems, a scheme for the consistent integration of modally reduced multibody systems subjected to holonomic constraints is developed in the present paper. As opposed to the conventional approach, in which the floating frame of reference formulation is combined with component mode synthesis for approximating the flexible deformation, an alternative, recently proposed formulation based on absolute coordinates is adopted in the analysis. Owing to the linear relationship between the generalized coordinates and the absolute displacement, the inertia terms in the equations of motion attain a very simple structure. The mass matrix remains independent of the current state of deformation and the velocity dependent term known from the floating frame approach vanishes due to the absence of relative coordinates. These advantageous properties facilitate the construction of an energy and momentum consistent integration scheme. By the mid-point rule, algorithmic conservation of both linear and angular momentum is achieved. In order to consistently integrate the total energy of the system, the discrete derivative needs to be adopted when evaluating the strain energy gradient and the derivative of the algebraic constraint equations.
A Task Driven Approach to the Synthesis of Spherical 4R Linkages Using Algebraic Fitting Method
Authors: Zhao Ping , Li Xiangyun , Purwar Anurag , Thakkar Kartik , Ge Q. J.
Published: February 2014

This paper studies the problem of spherical 4R motion approximation from the viewpoint of extraction of circular geometric constraints from a given set of spherical displacements. This paper extends our planar 4R linkage synthesis work to the spherical case. By utilizing kinematic mapping and quaternions, we map spherical displacements into points and the workspace constraints of the coupler into intersection of algebraic quadrics (called constraint manifold), respectively, in the image space of displacements. The problem of synthesizing a spherical 4R linkage is reduced to finding a pencil of quadrics that best fit the given image points in the least squares sense. Additional constraints on the pencil identify the quadrics that represent a spherical circular constraint. The geometric parameters of the quadrics encode information about the linkage parameters which are readily computed to obtain a spherical 4R linkage that best navigates through the given displacements. The result is an efficient and largely linear method for spherical four-bar motion generation problem.
A Cogging Torque Assisted Motor Driven Valve Actuation System for Internal Combustion Engines
Authors: Reinholz Bradley A. , Seethaler Rudolf J.
Published: February 2014

Electromechanical valve actuation (EVA) for internal combustion engines promises to significantly improve engine efficiency and lower emissions by reducing pumping losses and allowing for novel combustion strategies. However, current designs have not been able to meet the stringent performance criteria for reliability, efficiency, acoustic emissions, weight, and cost that are required by the automotive industry. This paper describes a novel cogging torque assisted motor driven (CTAMD) valve actuation system that promises to meet both the performance and robustness requirements. In contrary to existing EVA systems that recover the kinetic valve energy using a mechanical spring system, the CTAMD system recovers kinetic energy in a magnetic field. This allows for high efficiency while maintaining a simple and elegant electromechanical design. This paper describes the characteristics of CTAMD systems and outlines an electromechanical design for such a system. Then computer simulations of the proposed design are used to demonstrate the expected performance of the system. Finally, the simulated results are compared to other EVA systems to highlight the anticipated improvements.
Integrating Design Knowledge in Educational Curricula: Reflections From the Development of a Multi-Disciplinary Programme in Product Design
Authors: McKay Alison , de Pennington Alan , Giard Jacques
Published: February 2014

A challenge for design educators lies in balancing demands from employers for graduates who are “ready for work” on graduation and universities’ academic goals for excellence by creating graduates with knowledge and skills that reflect the cognate basis of the discipline they are studying. In 2001, in response to this challenge, a multi-disciplinary undergraduate programme in Product Design was proposed that combined applied technology and design. Graduates would have knowledge, technical literacy and personal skills, such as creativity and team-working, essential to their future working success. The curriculum would focus on the skills and knowledge needed by design professionals and would be delivered in a learning environment that bridged the academic milieu and professional world. Twelve years on the programme has produced 273 graduates: 97 Masters of Design and 176 Bachelors. In this paper we reflect on experiences in creating a multi-disciplinary programme in Product Design that addresses these different needs. Conclusions are drawn for educators creating multi-disciplinary programmes of study and academic administrators whose engagement is essential in the delivery of programmes that span the disciplinary silos and infrastructures.
A Helical Gear Pair Pocketing Power Loss Model
Authors: Talbot David , Kahraman Ahmet , Seetharaman Satya
Published: February 2014

A new fluid dynamics model is proposed to predict the power losses due to pocketing of air, oil, or an air-oil mixture in the helical gear meshes. The proposed computational procedure treats a helical gear pair as combination of a number of narrow face width spur gear segments staggered according to the helix angle and forms a discrete, fluid dynamics model of the medium being pocketed in the gear mesh. Continuity and conservation of momentum equations are applied to each coupled control volume filled with a compressible fluid mixture to predict fluid pressure and velocity distributions from, which the instantaneous pocketing power loss is calculated. The proposed model is exercised in order to investigate fluid pressure and velocity distributions in time, as well as pocketing power loss as a function of speed, helix angle and oil-to-air ratio.
Global “Eclipse” Bifurcation in a Twinkling Oscillator
Authors: Panigrahi Smruti R. , Feeny Brian F. , Diaz Alejandro R.
Published: February 2014

This work regards the use of cubic springs with intervals of negative stiffness, in other words “snap-through” elements, in order to convert low-frequency ambient vibrations into high-frequency oscillations, referred to as “twinkling”. The focus of this paper is on a global bifurcation of a two-mass chain which, in the symmetric system, involves infinitely many equilibria at the bifurcation point. The structure of this “eclipse” bifurcation is uncovered, and perturbations of the bifurcation are studied. The energies associated with the equilibria are examined.
A Novel Method for Driving Condition Recognition Based on Compressed Sensing
Authors: Zhang Xing , Dong Zuomin , Crawford Curran
Published: February 2014

Much research has been conducted in the area of driving condition recognition, which is adopted in the control system of hybrid electric vehicle (HEV) and driving assistance system of both alternative energy and conventional vehicle. In this manuscript, Compressed Sensing will be firstly used to improve the efficiency of vehicle speed sampling, then Support Vector machine will be employed to classify the results of Compressed Sensing into several driving condition types. Finally, the recognition results will be compared with traditional driving condition recognition methods (without Compressed Sensing) and conclusion can be drawn that Compressed Sensing can not only increase the efficiency of vehicle speed sampling, but also improve the classification accuracy.
Second-Order Perturbation Analysis of Low-Amplitude Traveling Waves in a Periodic Nonlinear Chain
Authors: Panigrahi Smruti R. , Feeny Brian F. , Diaz Alejandro R.
Published: February 2014

Traveling waves in one-dimensional nonlinear periodic structures are investigated for low-amplitude oscillations using perturbation analysis. We use second-order multiple scales analysis to capture the effects of quadratic nonlinearity. Comparisons with the linear and cubical nonlinear cases are presented in the dispersion relationship, group velocity and phase velocity and their dependence on wave number and amplitude of oscillation. Quadratic nonlinearity is shown to have a significant effect on the behavior.
The Impact of Asynchronous GPGPU Behaviors on Stochastic Simulation
Authors: Steuben John C. , Turner Cameron J.
Published: February 2014

This work examines the effect of one key aspect of General Purpose Graphics Processing Unit (GPGPU) computing on the realism and fidelity of stochastic simulations. In particular it is shown that the asynchronous nature of GPGPU computing can be leveraged to produce increased fidelity and realism, compared to conventional computing methods, when applied to probabilistic or stochastic simulations. This is a multifaceted argument that shows:

1) Asynchronous behaviors are essential to produce high computational throughput on GPGPU devices, and thus allow more rigorous sampling, which in turn enables a deeper understanding of the underlying stochastic processes.

2) Asynchronous GPGPU computing can eliminate the “global clock” present in simulations and potentially produce a better representation of the underlying process.

This paper also attempts to give a working introduction to GPGPU computing, and to the applications of this technology in the field of stochastic simulation. A range of literature regarding these simulations is also surveyed, in order to provide context. A demonstration of synchronous versus asynchronous algorithms for robot swarm path planning is used to illustrate this discussion. Several notes on the limitations of GPGPU computing in this field are also made, along with remarks regarding future development of GPGPU-accelerated stochastic simulations.
Mathematical Insights of Mode Localization in Nearly Cyclic Symmetric Rotors With Mistune
Authors: Chen Y. F. , Shen I. Y.
Published: February 2014

In this paper, we develop a mathematical analysis to gain insights of mode localization often encountered in nearly cyclic symmetric rotors with mistune. First, we conduct a Fourier analysis in the spatial domain to show that mode localization can appear only when a group of tuned rotor modes form a complete set in the circumferential direction. In light of perturbation theories, these tuned rotor modes must also have very similar natural frequencies, so that they can be easily reoriented when the mistune is present to form localized modes. Second, the natural frequency of these tuned rotor modes can further be represented in terms of a mean frequency and a deviatoric component. A Rayleigh-Ritz formulation then shows that mode localization occurs only when the deviatoric component and the rotor mistune are about the same order. As a result, we can develop an effective visual method — through use of the deviatoric component and the rotor mistune — to precisely identify those modes needed to form localized modes. Finally, we show that curve veering with respect to engine orders is not a necessary condition for mode localization to occur in the context of free vibration. Not all curve veering leads to mode localization, and not all modes in curve veering contribute to mode localization. A numerical example confirms the findings above.
Shock Isolation in Finite-Length Dimer Chains With Linear, Cubic and Hertzian Spring Interactions
Authors: Smith Eric , Ferri Al
Published: February 2014

A numerical investigation to mitigate the effects of shock in finite 1:1 dimer chains is performed. Dimer chains consist of alternating light and heavy masses. Changing the mass ratio has provided interesting results in previous research. In particular, in the case of Hertzian contacts with zero-preload, certain mass ratios have revealed minimal levels of transmitted force. This paper examines this phenomena from the perspective of utilizing it in practical isolation systems. The zero-preload Hertzian contact case is contrasted with chains connected by linear or cubic springs. Through numerical simulations, tradeoffs are examined between displacement and transmitted force.
Novel Pixelated Multicellular Representation for Origami Structures That Innovates Computational Design and Control
Authors: Li Wei , McAdams Daniel A.
Published: February 2014

Origami is a traditional Asian fine art of creating three-dimensional structures by folding paper. Recently, engineers have started to exploit the functional advantages of foldable structures. Formal representations of origami structures are limited. Most of the origami research describes an origami structure by providing the geometric properties of creases and vertices. This paper proposes a novel representation of an origami structure by describing the faces. An origami sheet is first pixelated with evenly distributed cellular agents, referred to as cells. Pixelization makes the origami structurally analogous to an LED matrix screen, with each of the cells being one LED pixel on the screen. Every cell will possess two key properties that contribute to determine the entire pattern: the cell type, which is analogous to the color of the LED; and the cell size, which is analogous to the light intensity of the LED. Therefore, a collection of cells with the same cell type (color) could represent the rough profile of an origami face, while the sizes of the cells are used to determine the face borders.. Creases and vertices can be subsequently determined by attaining the precise borders among faces. In this paper, we will also propose a crease restoration algorithm to determine the face borders and creases that then enable a fold to the final origami shape. The novel pixelated multicellular representation of origami enables new computational origami design methods as well as new self-folding origami structures.
Unbalance Identification in Large Steam Turbo-Generator Unit Using a Model-Based Method
Authors: Pennacchi Paolo , Vania Andrea , Chatterton Steven , Nistor Ionel , Voinis Philippe , Ricci Roberto , Borghesani Pietro
Published: February 2014

Fault identification in industrial machine is a topic of major importance under engineering point of view. In fact, the possibility to identify not only the type, but also the severity and the position of a fault occurred along a shaft-line allows quick maintenance and shorten the downtime. This is really important in the power generation industry where the units are often of several tenths of meters long and where the rotors are enclosed by heavy and pressure-sealed casings.

In this paper, an industrial experimental case is presented related to the identification of the unbalance on a large size steam turbine of about 1.3 GW, belonging to a nuclear power plant. The case history is analyzed by considering the vibrations measured by the condition monitoring system of the unit. A model-based method in the frequency domain, developed by the authors, is introduced in detail and it is then used to identify the position of the fault and its severity along the shaft-line. The complete model of the unit (rotor – modeled by means of finite elements, bearings – modeled by linearized damping and stiffness coefficients and foundation – modeled by means of pedestals) is analyzed and discussed before being used for the fault identification. The assessment of the actual fault was done by inspection during a scheduled maintenance and excellent correspondence was found with the identified one by means of authors’ proposed method.

Finally a complete discussion is presented about the effectiveness of the method, even in presence of a not fine tuned machine model and considering only few measuring planes for the machine vibration.