bluuebunny/crossref_metadata_2025 huggingface dataset:
A Framework for Concurrent Consideration in Advanced Product Development Technology Selection
Authors: Farrugia P. J. , Francalanza E. , Coppini K.
Published: June 2012

In order to survive in the modern market, manufacturing companies need to invest in Advanced Product Development Technologies (APDTs). The problem many companies face, however, is the huge variety of possible technologies available. Examples of these are Stereo Lithography Apparatus (SLA), Selective Laser Sintering (SLS), Fused Deposition Modelling (FDM), Virtual Prototyping and many others. A literature review revealed that there were many attempts at implementing decision support tools, for the selection of the most appropriate APDT for a particular application. These tools were limited in scope to a small range of technologies. Examples of this are the several attempts in the field of Rapid Prototyping. Furthermore the approaches which exist focus on the technical requirements only of the machine and very rarely take into consideration the needs of the manufacturing organization as a whole. Therefore as a result, there is a lack of decision support tools for selecting APDTs while considering the different Product Development (PD) stages. One area in which these APDTs excel is in the reduction of lead times to develop a product. Therefore the implementation of such technologies can potentially reduce the time-to-market of companies investing in them. The question which remains unanswered is: how does one choose the technology which will deliver the greatest improvement with regards to time-to-market? To address this question, this research developed a framework which allows stakeholders in the organization to select the most appropriate technology to reduce time-to-market for companies following the Integrated Product Development (IPD) model. This framework is based on their requirements and a structured approach. This paper presents the framework developed to this end, which was implemented in an Information and Communication Technology (ICT)-based prototype tool. The novelty of the proposed framework lies in the fact that it combines Multiple Attribute Decision Methods (MADM), more specifically Analytical Hierarchical Process (AHP) and Simple Additive Weighting (SAW) along with the IPD model and continuous improvement practices. The validity of the proposed ICT tool was evaluated qualitatively by stakeholders from different PD perspectives such as sales and marketing, product design and manufacturing. The evaluation results provide a degree of evidence that the proposed framework and ICT tool were effective at meeting the time-to-market shortcomings of current product development practices of companies.
Assistive Rehabilitation Device for the Joints of the Lower Limb
Authors: Deaconescu Tudor T. , Deaconescu Andrea I. , Petre Ioana G.
Published: June 2012

Applying continuous passive rehabilitation movements as part of the recovery program of patients with post-traumatic disabilities of the bearing joints of the inferior limbs requires the development of new high performance equipment. The proposed equipment is designed to be deployed in rehabilitation medical care, its specific objectives being maintenance and recovery of body functions by means of kinetic and orthotic techniques. The paper presents a variant of rehabilitation equipment the novelty of which consists in the utilization of compliant (soft) fluidic actuators of linear type and variable stiffness. The proposed rehabilitation equipment benefits from a cost efficient, simple and robust construction, being easy to use by persons affected by dysfunctions of the bearing joints. The paper presents kinematic, geometrical and dynamic modeling of the proposed rehabilitation equipment, highlighting its advantages compared to equipment endowed with electric-mechanical linkages. Further, the paper presents the actuation diagram of the equipment. Conceived to be actuated by pneumatic muscles the equipment represents an absolute novelty.
The Underwater Effects of High Power, High Frequency Acoustic Noise on MEMS Gyroscopes
Authors: Yunker William N. , Soobramaney Pregassen , Black Meagan , Dean Robert N. , Flowers George T. , Ahmed Anwar
Published: June 2012

Unlike their macroscale counterparts, MEMS gyroscopes use a vibrating proof mass rather than a rotational mass to sense changes in angular rate. They are also smaller and less expensive than traditional gyroscopes. For this reason, MEMS gyroscopes are being used in many new applications, some of which include operation in harsh environments. There has been much research on the negative effects of the performance of MEMS gyroscopes in environments that experience mechanical shock, high frequency vibration, and high frequency acoustic noise in air. However, MEMS gyroscopes are beginning to be used in underwater applications such as autonomous underwater vehicles, digital compasses, and torpedo guidance systems. The results of this experiment demonstrate that MEMS gyroscopes submerged in water are susceptible to high power, high frequency acoustic noise at and near the resonant frequency of the proof mass. These effects are demonstrated using the ADXRS300 MEMS gyroscope.
A New Approach to Modeling Discrete Nonlinear Constraints in Continuous Systems: The Method of Discontinuous Basis Functions
Authors: Brake M. R. , Segalman D. J.
Published: June 2012

Solutions for analytical models of systems with nonlinear constraints have focused on exact methods for satisfying the constraint conditions. Exact methods often require that the constraint can be expressed in a piecewise-linear manner, and result in a series of mapping equations from one linear regime of the constraint to the next. Due to the complexity of these methods, exact methods are often limited to analyzing a small number of constraints for practical reasons. This paper proposes a new method for analyzing continuous systems with arbitrary nonlinear constraints by approximately satisfying the constraint conditions. Instead of dividing the constraints into multiple linear regimes, a discontinuous basis function is used to supplement the system’s linear basis functions. As a result, precise contact times are not needed, enabling this method to be more computationally efficient than exact methods. While the discontinuous basis functions are continuous in displacement, their derivatives contain discontinuities that allow for the nonlinear forces to be accounted for with the assumption that the nonlinear constraints are able to be modeled in a discrete manner. Since each nonlinear constraint requires only one associated discontinuous basis function, this method is easily expanded to handle large numbers of constraints. In order to illustrate the application of this method, an example with a pinned-pinned beam is presented.
Optimal Synthesis of a New Spherical Parallel Mechanism for Application to Tele-Echography Chain
Authors: Laribi M. A. , Essomba T. , Zeghloul S. , Poisson G.
Published: June 2012

This paper considers the practice of a tele-echography through a new slave holder robot for a remote echographic diagnostic application. This robot is integrated in a master-slave system called ‘Robotic Platform for an Interactive Tele-echographic System’ (PROSIT ANR French national project). The proposed approach is based on motion capture of an expert’s gestures during the echography examination. The medical gestures were analyzed in terms of positions and velocities; the result has been used in the definition of the kinematics specifications of the proposed manipulator. The effective workspace size of a standard echography act, done by the medical expert, is determined through an experimental study. The evaluation of the workspace is based on the use of the Vicon Nexus motion capture system. The spherical parallel mechanism (SPM) has been selected because of its characteristics meeting the constraint requirements. In addition this architecture offers an excellent stiffness, high precision and is light weight. The design problem of a new parallel probe-holder robot according to the identified experimental workspace for the tele-echography system is presented. In this work, in order to increase the workspace volume of the manipulator, a minimal set of geometrical parameters of spherical parallel manipulators are optimized to find the maximum workspace. Seven independent design parameters have been identified. The optimal synthesis of spherical parallel manipulators is performed using a real-coded genetic algorithm (GA) based method. An optimal study of the orientation workspace is also presented.
Modeling of Impressed Current Cathodic Protection Anode Arrangements for Storage Tank Bottoms
Authors: Adey Robert , Baynham John , Peratta Cristina
Published: June 2012

Above ground tanks are frequently used for the storage of Oil & Gas products and they can present a challenge to design an optimum corrosion control system. The base of the tank lies on or near the surface of the ground and is in contact with the material used to support the tank and therefore presents a corrosion challenge. One method of protecting the bottom of a tank is by use of an impressed current cathodic protection (ICCP) system. There are a number of types of Cathodic Protection systems which are designed to protect the tank base in these circumstances. The details of the design of such a system are very important for optimal performance and also the cost, if a number of such systems are to be installed The consequence of a poor design can be uneven distribution of protection potential on the tank base or in the worst cases regions where corrosion of the tank base can take place. An over designed system on the other hand can have significant economic consequences both in terms of installation cost and running costs. Computer modeling is now widely used to optimize CP Designs and verify that the design of the cathodic protection (CP) system meets the design requirements. In this paper a modeling tool is presented which enables corrosion engineers to evaluate the performance of tank base CP systems by predicting the protection provided to the tank for a given CP design. The paper describes and discusses all aspects of the modeling methodology, which it then applies to several different design concepts.
Determination of the Most Dangerous Meshing Point for Modified Hourglass Worm Drives
Authors: Zhao Yaping , Wu Tianchao
Published: June 2012

A kind of modified hourglass worm drives, which is frequently called the type II worm gearing for short, has various favorable meshing features. Nevertheless, its sole shortcoming is the undercutting of the worm wheel. In the condition of adopting slight modification, this problem can be overcome due to the removal of a part of one sub-conjugate area containing the curvature interference limit line. In order to measure the effect of the avoidance of undercutting, a strategy to determine the meshing point in the most severe condition is proposed for a type II worm drive. The presented strategy can be divided into two steps. The first step is to establish a system of nonlinear equations in five variables in accordance with the theory of gearing. The second step is to solve the procured nonlinear equations by numerical iterative method to ascertain the meshing point required. A numerical example is presented to verify the validity and feasibility of the proposed scheme.
Trajectory Tracking of Underactuated Multibody Systems
Authors: Reichl Stefan , Steiner Wolfgang
Published: June 2012

This work presents three different approaches in inverse dynamics for the solution of trajectory tracking problems in underactuated multibody systems. Such systems are characterized by less control inputs than degrees of freedom. The first approach uses an extension of the equations of motion by geometric and control constraints. This results in index-five differential-algebraic equations. A projection method is used to reduce the systems index and the resulting equations are solved numerically. The second method is a flatness-based feedforward control design. Input and state variables can be parameterized by the flat outputs and their time derivatives up to a certain order. The third approach uses an optimal control algorithm which is based on the minimization of a cost functional including system outputs and desired trajectory. It has to be distinguished between direct and indirect methods. These specific methods are applied to an underactuated planar crane and a three-dimensional rotary crane.
Rapid Mapping and Exploration of Configuration Space
Authors: Nelaturi Saigopal , Lysenko Mikola , Shapiro Vadim
Published: June 2012

We describe a GPU-based computational platform for six-dimensional configuration mapping, which is the description of the configuration space of rigid motions in terms of collision and contact constraints. The platform supports a wide range of computations in design and manufacturing, including three and six dimensional configuration space obstacle computations, Minkowski sums and differences, packaging problems, and sweep computations. We demonstrate dramatic performance improvements in the special case of configuration space operations that determine interference-free or containment-preserving configurations between moving solids. Our approach treats such operations as convolutions in the six dimensional configuration space that are efficiently computed using the Fast Fourier Transform (FFT). The inherent parallelism of FFT algorithms facilitates a straightforward implementation of convolution on GPUs with existing and freely available libraries, making all such six dimensional configuration space computations practical, and often interactive.
Development of a Method for Measuring Damping in Bolted Joints
Authors: Goyder Hugh , Ind Philip , Brown Daniel
Published: June 2012

Bolted joints are a significant source of vibration damping but are extremely difficult to model within computer simulations. In order to make progress, good quality experiment data is needed to provide a basis for modelling and an understanding of the mechanisms involved. An apparatus for measuring damping in a lap joint has been developed in which bolted joints are exercised by swinging masses in a resonant configuration. The apparatus is set into vibration and then released so that the vibration decays with the bolt damping controlling the decay. After some signal processing the energy lost per cycle is extracted. The repeatability of the bolted joint behaviour is an issue of concern and this is examined by analysing a series of tests. Although largely successful the system probably applies too large a force to the joint which exhibits some slip which then contributes to the lack of repeatability observed.
Machining Experiments for Establishment of Parameters for Deviation-Based Cost of Manufacturing Formulations
Authors: Pramanik Nilmani , Deshmukh Parikshit
Published: June 2012

Realistic modeling of cost of manufacturing is essential for estimating cost of a product as well as for optimizing alternate manufacturing strategies. There are many factors that affect cost of manufacturing but the single most important parameter for estimating the cost of manufacturing is tolerance (deviation from the nominal size). In the past, most of the cost formulations were based on some inverse power function of a single tolerance parameter. However, it has been shown in our earlier work that when geometric tolerances are used to control the features, it is very difficult (and may not always be feasible) to establish a single tolerance parameter that can be used for estimating the cost. In our earlier work, we have established generic cost formulations based on the deviations of all features of a part and the mating relations between parts. It has been shown that the deviation based cost formulations could be used to establish cost of manufacturing at various geometric tolerancing conditions and the deviation parameters could be mapped to the geometric tolerancing specifications as per ASME Y14.5. In this paper results from manufacturing experiments carried out to establish process-specific machining parameters for the cost functions are presented. The parameters that have been considered are: turning operations at various combination of speed, feed and depth of cut on cylindrical rods (planar circular face) of specified nominal size and tolerances. The deviations of the machined surfaces (surface roughness) are then measured using a digital profilometer and the data from these measurements are analyzed for generation of best fitted planes for establishing the deviation parameters for the specified tolerance conditions. Results from these experiments are presented and applicability and limitations of these cost models are discussed. Future research steps for development of parameters for other remaining features (conical, spherical, etc.) are discussed.
An Investigation of Product Modularity and Supply Chain Performance at the Product Design Stage
Authors: Chiu Ming-Chuan , Okudan Gu¨l E.
Published: June 2012

The benefit of integrating product design decisions and supply chain design decisions has been noticed by researchers. This integration can provide better communication between design teams and operations groups. Accordingly, potential supply chain risks can be highlighted before the launch of a new product. Modularization is one of the most critical product design and supply chain design decisions because it will determine the assembly sequence and potential suppliers of the product in the supply chain execution. However, the impact of modularity level on supply chain performance is still unclear. The objective of this study is to tackle this issue. The proposed method covers product design functions and supply chain design functions, hence the product design decisions and supply chain design decisions can be considered simultaneously. The supply chain performance of all design concepts is comprehensively investigated so as to analyze the impact of modularity on supply chain performance regarding lead-time and cost. The results show that increased modularity is advantageous for the time-based performance of supply chain network whereas decreased modularity demonstrates superiority on cost performance.
Real-Time Validation and Control Environment for Parallel Robot Control Design
Authors: Zubizarreta A. , Portillo E. , Cabanes I. , Marcos M. , Pinto Ch.
Published: June 2012

Due to their high performance when executing high-speed and accurate tasks, parallel robots have became the focus of many researchers and companies. However, exploiting the full potential of these robots requires a correct mechatronic design, in which the designed mechanism has to be controlled by a suitable control law in order to achieve the maximum performance. In this paper a novel Validation and Control Environment (VALIDBOT) is proposed as a support for the control design and experimental testing stages of these robots. The proposed open and flexible environment is designed to meet rapid prototyping requirements, offering a high level framework for both students and researchers. The capabilities of the environment are illustrated with an application case based on a 5R parallel robot prototype in which a modified CTC controller is tested.
Geometric Design of Spherical Serial Chains With Curvature Constraints in the Environment
Authors: Robson Nina , Tolety Anurag
Published: June 2012

This paper builds up on recent results on planar kinematic synthesis with contact direction and curvature constraints on the workpiece. We consider the synthesis of spherical serial chains to guide a rigid body, such that it does not violate normal direction and curvature constraints imposed by contact with objects in the environment. We show how to derive these constraints from the geometry of the task and transform them into conditions on velocity and acceleration of points in the moving body to obtain synthesis equations which can be solved by algebraic elimination. Trajectory interpolation formulas yield the movement of the chain with the desired contact properties in each of the task positions. An example shows the application of the developed theory to the failure recovery of a robot manipulator, using kinematic synthesis techniques.
Finite Element Analysis of Tire and Pavement Interaction
Authors: Kim Kwangwon , Ju Jaehyung , Kim Doo-Man , Rhie Swangwa
Published: June 2012

Nonlinear material models of a tire and a pavement appear to be important to precisely evaluate both tire performance and stresses of a pavement. In this paper, nonlinear tire and pavement material models are used and their contract pressures of a tire and stresses of a pavement are investigated. The results with the nonlinear material models are compared with those of simplified tire and pavement models. Finite element (FE) analysis with ABAQUS is used for simulating four different interaction models of tire and pavement. An interaction model with a hyperelastic tire and an elasto-viscoplastic pavement shows accurate contract pressures of a tire and stress distributions of a pavement.
Separable Polyurethane Solid Tires for a Folding Bike
Authors: Ryu Sarom , Ju Jaehyung , Kim Doo-Man , Heo Hyeonu
Published: June 2012

With increasing awareness of energy depletion and environmental pollution, bikes have been paid more attention as an important transportation tool. Folding or separable part design of a bike may increase a use of bikes due to its portable capability. In this study, we suggest a novel separable solid bike tire for a folding bike use. Finite element model with ABAQUS is used to model a polyurethane (PU) separable solid tire. Vertical stiffness and contact pressure are compared with those of a conventional pneumatic bike tire. Elliptical hollow cross-sections of a PU solid tire are investigated to match a vertical stiffness and contact pressure of a conventional pneumatic bike tire. The suggested PU solid tire with an elliptical hollow cross-section shows a lower contact pressure than a pneumatic bike tire when they are designed to be the same load carrying capability.
Probabilistic Life Prediction for High Temperature Low Cycle Fatigue Using Energy-Based Damage Parameter and Accounting for Model Uncertainty
Authors: Zhu Shun-Peng , Huang Hong-Zhong , Ontiveros Victor , He Li-Ping , Modarres Mohammad
Published: June 2012

Probabilistic methods have been widely used to account for uncertainty from various sources to predict fatigue life for components or materials. The Bayesian approach can potentially give more accurate estimates by combining test data with technical knowledge available from theoretical analyses and/or previous experimental results. The aim of the present paper is to develop a probabilistic methodology for high temperature low cycle fatigue life prediction using an energy-based damage parameter and to demonstrate the use of an efficient probabilistic method. Accordingly, a Black-box approach is used to quantify model uncertainty for three damage parameters (the generalized damage parameter, SWT and plastic strain energy density (PSED)) using measured differences between experimental data and model predictions. The proposed model was verified using experimental data for nickel-base Superalloy GH4133 under different temperatures from literature. The results show that the uncertainty bounds using the generalized damage parameter for life prediction are tighter than that of SWT and PSED methods, which leads to better decision making based on the same available knowledge.
Numerics of Non-Smooth Multibody Systems
Authors: Pfeiffer Friedrich
Published: June 2012

The theory of non-smooth multibody dynamics with unilateral contacts is now well established, for example in terms of measure equations of motion added by complementarities or formulated with the help of differential inclusions. Most researchers today focus on numerical methods for solving these systems, because computing times especially for large systems are a problem. Time-stepping schemes for time-integration, pivoting or iterative algorithms for solving the complementarity problem and the Augmented Lagrangian approach are methods of increasing numerical efficiency for large systems. The paper describes new findings for unilateral multibody systems and discusses two large industrial examples, namely the dynamics of a roller coaster and the behavior of a drop tower featuring hydraulic components.
Natural Coordinates in the Optimal Control of Multibody Systems
Authors: Betsch Peter , Siebert Ralf , Sa¨nger Nicolas
Published: June 2012

The formulation of multibody dynamics in terms of natural coordinates (NCs) leads to equations of motion in the form of differential-algebraic equations (DAEs). A characteristic feature of the natural coordinates approach is a constant mass matrix. The DAEs make possible (i) the systematic assembly of open-loop and closed-loop multibody systems, (ii) the design of state-of-the-art structure-preserving integrators such as energy-momentum or symplectic-momentum schemes, and (iii) the direct link to nonlinear finite element methods. However, the use of NCs in the optimal control of multibody systems presents two major challenges. First, the consistent application of actuating joint-forces becomes an issue since conjugate joint-coordinates are not directly available. Secondly, numerical methods for optimal control with index-3 DAEs are still in their infancy. The talk will address the two aforementioned issues. In particular, a new energy-momentum consistent method for the optimal control of multibody systems in terms of NCs will be presented.
Visuomotor Tracking Tasks With Delayed Pursuit and Escape
Authors: Milton John , Lippai Joshua , Bellows Rachel , Blomberg Andrew , Kamimura Atsushi , Ohira Toru
Published: June 2012

Virtual stick balancing (VSB) is a manual visuomotor tracking task that involves interplay between a human and a computer in which the movements are programmed to resemble those of balancing a stick at the fingertip. Since time delays and random perturbations (“noise”) are intrinsic properties of this task, we modeled VSB as a delayed pursuit-escape process: the target movements are described by a simple random walk and those movements controlled by the computer mouse by a delayed random walk biased towards the target. As subjects become more skilled, a stereotyped and recurring pursuit-escape pattern develops in which the mouse pursues the target until it overtakes it, causing the target to move in a different direction, followed, after a lag, by the pursing mouse. The delayed pursuit-escape random walk model captured the qualitative nature of this tracking task and provided insights into why this tracking task always fails at some point in time, even for the most expert subjects.
P-SMOTE: One Oversampling Technique for Class Imbalanced Text Classification
Authors: Wang Jingjing , Lu Wen Feng , Loh Han Tong
Published: June 2012

The importance of mining patents to support product design has been recognized, because patents are the major information source to support innovation and contain novel ideas, which usually cannot be found in published academic papers. In patent text mining, a basic issue is patent classification. However, automatic patent classification is difficult. One potential cause of the difficulty is the imbalanced dataset i.e. the interested positive class is minor while uninterested negative class is major. To alleviate the problem of imbalanced dataset and improve the performance of a Support Vector Machine (SVM) classifier, this study proposes P-SMOTE, a new oversampling technique which focuses on the blank spaces along positive borderline of a SVM. The proposed technique was firstly investigated on Reuters-21578, which is a standard text classification dataset. Then, P-SMOTE was applied to a design patent document dataset. It was observed that a SVM classifier with P-SMOTE, compared to a SVM classifier only, successfully achieved better results.
Determining Necessary Parameters for Nanoinjector Electrodes During Attraction
Authors: Toone Nathan C. , Jensen Brian D.
Published: June 2012

This paper outlines the adaptation of a mathematical computer model used to simulate the motion of DNA particles in order to determine the best geometry and setup for a prototype cell injection system. The model predicts DNA motion due to electrophoresis near micromachined electrodes. Ten key electrode parameters are identified to test for significance, and three key test measurements are identified to help compare the various setups. A simple design of experiment is used to organize and analyze the data collected from forty-one simulations of the DNA motion within the electric field. Based on the simulations of attracting DNA to the lance for injection, it is found that a compact ring electrode placed underneath an insulated lance will yield the optimal results. Two additional areas for research are recommended.
Light Weight and Low-Misalignment Planetary Gear System for Open Rotor Power Gearbox
Authors: Matsuoka Tetsuya , Nishikawa Hiroyasu , Imai Hideyuki , Kijima Kenichi , Nishida Tooru , Goi Tatsuhiko
Published: June 2012

The future aero engines expected to have the best fuel efficiency are those with the open rotor propulsion system. It has two rows of propellers rotating in opposite directions. The rotational speeds of the propellers are reduced by a power gearbox. The power gearbox is designed as a differential planetary gear system with double helical teeth. The gearbox for aero engines needs to be lightweight and highly reliable. Misalignment on the gear pair affects adversely the reliability of the gears. The misalignment analysis of the power gearbox based on finite element analysis was carried out. The inclination of the planet spindles associated with the twisting deformation of the planet carrier was identified as the major cause of the misalignment. We developed an innovative design method to achieve the low misalignment and lightweight at the same time by optimizing the stiffness balance of the planet carrier. The optimization analysis was carried out extensively in the design work. The planet carrier design was named Analysis Configured Engineering planet Carrier (ACE CARRIER). A stress measurement was planned to validate the design concept of the ACE CARRIER. A test gearbox was manufactured.
Perturbation Analysis and Chaotic Dynamics of Rotating Blade With Varying Angular Speed
Authors: Chen Yan-ping , Yao Ming-Hui , Zhang Wei , Wang Qian
Published: June 2012

Perturbation analysis and chaotic dynamics of the rotating blade with varying angular speed are investigated. Centrifugal force, aerodynamic load and the perturbed angular speed due to the inconstant air velocity are considered. The rotating blade is treated as a pre-twist, presetting, thin-walled rotating cantilever beam. The nonlinear governing partial differential equations of the varying angular rotating blade are established by using Hamilton’s principle. Then, the ordinary differential equations of the rotating blade are obtained by employing the Galerkin’s approach during which Galerkin’s modes satisfy corresponding boundary conditions. The four-dimensional nonlinear averaged equations are obtained by applying the method of multiple scales. In this paper, the resonant case is 1:2 internal resonance-1/2 subharmonic resonance. The numerical simulation is used to investigate chaotic dynamics of the varying angular rotating blade. The results show that the system is sensitive to the rotating speed and there are chaotic motions.
On the Application of the Lu-Gre Model to Simulate Joint Friction in Multi-Body Systems
Authors: Kale Kedar Gajanan , Rampalli Rajiv
Published: June 2012

Advances in the application of multi-body simulation technology to real world problems have led to an ever increasing demand for higher fidelity modeling techniques. Of these, accurate modeling of friction is of strategic interest in applications such as control system design, automotive suspension analysis, robotics etc. Joints (sometimes referred to as constraints) play an important role in defining the dynamics of a multi-body system. Hence, it is imperative to accurately account for friction forces arising at these joints due to the underlying interface dynamics. In this paper, we discuss the application of LuGre, a dynamic friction model to simulate joint friction. We choose the LuGre model due to its ability to capture important effects such as the Stribeck effect and the Dahl effect. The native 1-d LuGre model is extended to formulate friction computations for non-trivial joint geometries and dynamics in 2 and 3 dimensions. It is also extended to work in the quasi-static regime. Specific applications to revolute, cylindrical and spherical joints in multi-body systems are discussed. Finally, an engineering case study on the effects of joint friction in automotive suspension analysis is presented.
Towards Parametric Environmental Profiles of Complex Industrial Systems in Preliminary Design Stage
Authors: Cluzel Franc¸ois , Yannou Bernard , Leroy Yann , Millet Dominique
Published: June 2012

The eco-design of complex industrial systems becomes a major issue for the concerned companies. Life Cycle Assessment (LCA) in particular is more adapted to “classical” products such as consumer goods. Performing LCA of such systems requires some thoughts to ensure significant results, for example concerning data granularity and quality. This article proposes a Life Cycle Assessment of an Alstom Grid AC/DC conversion substation for the aluminium industry. This LCA integrates first answers to the previous limitations. Very interesting results permit to orient the eco-design strategy of the company. Moreover they lead to imagine original ways to configure the system. Thus a first and simple parametric LCA model is proposed: four different electrical sources are used to analyze the sensitivity of the design factors to the environmental impacts of the substation. Based on design of experiments, a more advanced model of such a tool would permit to identify the best configuration in terms of environmental performance, costs and reliability.
Spatial-Beam Large-Deflection Equations and Pseudo-Rigid-Body Model for Axisymmetric Cantilever Beams
Authors: Ramirez Issa A. , Lusk Craig P.
Published: June 2012

The kinematic equations for approximating the deflection of a three-dimensional cantilever beam were developed. The numerical equations were validated with a Finite Element Analysis program. With these equations, a pseudo-rigid-body model (PRBM) for an axisymmetric straight beam was developed. The axisymmetric PRBM consists of a spherical joint connecting two rigid links. The location of the deformed end of the beam is determined by two angles and the characteristic radius factor. The angle of the beam with respect to the vertical axis depends on the direction of the force with respect to the undeformed coordinate system. The Pearson’s correlation coefficient for the Finite Element Analysis model and the numerical integration is 0.952.
Structural Optimization of Lattice Materials
Authors: Vigliotti Andrea , Pasini Damiano
Published: June 2012

Lattice materials are characterized at the microscopic level by a regular pattern of voids confined by walls. Recent rapid prototyping techniques allow their manufacturing from a wide range of solid materials, ensuring high degrees of accuracy and limited costs. The microstructure of lattice material permits to obtain macroscopic properties and structural performance, such as very high stiffness to weight ratios, highly anisotropy, high specific energy dissipation capability and an extended elastic range, which cannot be attained by uniform materials. Among several applications, lattice materials are of special interest for the design of morphing structures, energy absorbing components and hard tissue scaffold for biomedical prostheses. Their macroscopic mechanical properties can be finely tuned by properly selecting the lattice topology and the material of the walls. Nevertheless, since the number of the design parameters involved is very high, and their correlation to the final macroscopic properties of the material is quite complex, reliable and robust multiscale mechanics analysis and design optimization tools are a necessary aid for their practical application. In this paper, the optimization of lattice materials parameters is illustrated with reference to the design of a bracket subjected to a point load. Given the geometric shape and the boundary conditions of the component, the parameters of four selected topologies have been optimized to concurrently maximize the component stiffness and minimize its mass.
Mellin Convolution for Signal Filtering and Its Application to the Gaussianization of Le´vy Noise
Authors: Pagnini Gianni , Chen YangQuan
Published: June 2012

Noises are usually assumed to be Gaussian so that many existing signal processing techniques can be applied with no worry. However, in many real world natural or man-made systems, noises are usually heavy-tailed. It is increasingly desirable to address the problem of finding an opportune filter function for a given input noise in order to generate a desired output noise. By filtering theory, the probability density function of the output noise can be expressed by the integral of the product of the density of the input noise and the filter function. Adopting Mellin transformation rules, the Mellin transform of the unknown filter is determined by the Mellin transforms of the known density of the input noise and the desired density for the output noise. Finally, after the inversion, the Mellin-Barnes integral representation of the filter function is derived. The method is applied to compute the filter function to convert a Levy noise into a Gaussian noise.
The Solution of Linear Fractional Differential Equations Using the Fractional Meta-Trigonometric Functions
Authors: Lorenzo Carl F. , Malti Rachid , Hartley Tom T.
Published: June 2012

A new method for the solution of linear constant coefficient fractional differential equations of any commensurate order based on the Laplace transforms of the fractional meta-trigonometric functions and the R-function is presented. The new method simplifies the solution of such equations. A simplifying characterization that reduces the number of parameters in the fractional meta-trigonometric functions is introduced.
A Systematic Approach to Biologically-Inspired Engineering Design
Authors: Nagel Jacquelyn K. S. , Stone Robert B.
Published: June 2012

To facilitate systematic biologically-inspired design, a design methodology that integrates with function-based design methodologies has been formalized. The goals of this methodology are to go beyond the element of chance, reduce the amount of time and effort required for developing biologically-inspired engineering solutions, and bridge the seemingly immense disconnect between the engineering and biological domains. Using functional representation and abstraction to describe biological systems presents the natural designs in an engineering context and allows designers to make connections between biological and engineered systems. Thus, the biological information is accessible to engineering designers with varying biological knowledge, but a common understanding of engineering design methodologies. Two approaches to validation are presented. One examines current biologically-inspired products either in production or in literature to see if the systematic approach to biologically-inspired design can reproduce the existing designs. The second investigates needs-based design problems that lead to plausible biologically-inspired solutions. This work has demonstrated the feasibility of using systematic design for the discovery of innovative engineering designs without requiring expert-level knowledge, but rather broad knowledge of many fields.
Feature Sensitive Mesh Reconstruction by Normal Vector Cone Filtering
Authors: Ma Ji , Feng Hsi-Yung , Wang Lihui
Published: June 2012

Automatic and reliable reconstruction of sharp features remains an open research issue in triangle mesh surface reconstruction. This paper presents a new feature sensitive mesh reconstruction method based on dependable neighborhood geometric information per input point. Such information is derived from the matching result of the local umbrella mesh constructed at each point. The proposed algorithm is different from the existing post-processing algorithms. The proposed algorithm reconstructs the triangle mesh via an integrated and progressive reconstruction process and features a unified multi-level inheritance priority queuing mechanism to prioritize the inclusion of each candidate triangle. A novel flatness sensitive filter, referred to as the normal vector cone filter, is introduced in this work and used to reliably reconstruct sharp features. In addition, the proposed algorithm aims to reconstruct a watertight manifold triangle mesh that passes through the complete original point set without point addition and removal. The algorithm has been implemented and validated using publicly available point cloud data sets. Compared to the original object geometry, it is seen that the reconstructed triangle meshes preserve the sharp features well and only contain minor shape deviations.
Double Nonlinearity–Unbalance Response of Rotor on Ball Bearings With Squeeze Film Dampers
Authors: Fleming David P.
Published: June 2012

The nonlinear behavior of rolling-element bearings and squeeze-film dampers is well recognized; stiffness coefficients (and for dampers, damping coefficients also) increase as vibration amplitude increases. In the design of rotating systems using these elements, nonlinear aspects must be accounted for, and support properties chosen to handle the specific imbalance expected. Rolling-element bearings (e.g., ball bearings) are often used in combination with squeeze-film dampers (SFD). However, there seems to be no public information on the interaction of these two nonlinear elements. The purpose of this paper is to analytically document this interaction, and provide design guidance to optimize system performance for normal and extraordinary imbalance levels. Results show that a well-designed SFD in conjunction with a ball bearing performs similar to an optimized linear support with linear bearing, but care must be taken to ensure that the SFD can handle the maximum load encountered.
Nonlinear Dynamic Analysis of a Cracked Rotor-Bearing System With Fractional Order Damping
Authors: Xue Shiming , Cao Junyi , Chen Yangquan
Published: June 2012

Fatigue cracking of the rotor shaft is an important fault observed in rotating machinery of key industry, which can lead to catastrophic failure. Nonlinear dynamics of a cracked rotor system with fractional order damping is investigated by using a response-dependent breathing crack model. The four-th order Runge-Kutta method and ten-th order CFE-Euler (Continued Fraction Expansion-Euler) method are introduced to simulate the proposed system equation of fractional order cracked rotors. The effects of derivative order of damping, rotating speed ratio, crack depth, orientation angle of imbalance relative to the crack direction and mass eccentricity on the system dynamics are demonstrated by using bifurcation diagram, Poincare map and rotor trajectory diagram. The results show that the rotor system displays chaotic, quasi-periodic and periodic motions as the fractional order increases. It is also found that the imbalance eccentricity level, crack depth, rotational speed, fractional damping and crack angle all have considerable influence on the nonlinear behavior of the cracked rotor system.
Impact Noise From the Shaft-Bearing-Plate due to the Axial Excitation of Helical Gears
Authors: Park Chan IL
Published: June 2012

This work dealt with impact noise of a simplified gear system due to the axial excitation of helical gears. The simplified gear system was modeled by shaft-bearing-circular plate. Mesh force of helical gears for impact excitation was obtained from the solution of nonlinear equations of motion for helical gears with backlash and the regular change of mesh stiffness. Axial component of mesh force causes the longitudinal vibration of system and leads to transverse vibration of circular plate, which is acoustically significant. For longitudinal behavior of system, equation of motion of shaft-bearing-plate system due to axial excitation of motion was derived and dynamic analysis was performed. Plate displacement obtained by dynamic analysis becomes the source of impact noise. Impact noise was modeled by sound radiation from the clamped circular plate mounted in the infinite baffle. Impact noise characteristics of shaft-bearing-circular plate were investigated by numerical examples.
Estimation of Heat Flux Distribution in a Continuous Casting Mould by Inverse Heat Transfer Algorithms
Authors: Ranut Paola , Persi Cristiano , Nobile Enrico , Spagnul Stefano
Published: June 2012

In the continuous casting process of steel, the control of the mould heat removal is a key parameter, since it directly affects the shell growth and the stresses and strains that are produced in the mould. An inverse heat conduction model was developed to calculate mould heat transfer from temperature measurements, recorded using thermocouples buried inside the copper mould wall. The mould is water-cooled to solidify the hot metal directly in contact with it. The direct stationary conduction problem was solved both on a 2D and a 3D domain; the 2D geometry concerns only a longitudinal section of the mould, while in the 3D domain a whole face is considered. The inverse problem was solved using a Conjugate Gradient algorithm, a Genetic Algorithm and the Nelder-Mear SIMPLEX algorithm. For the 3D geometry, the heat flux profile calculated at the axis of the face is close to that obtained from the 2D model, although the former is slightly lower. For both geometries, there is a good agreement between numerical and experimental temperatures. Moreover, the 3D model provides a better estimate of the outlet water temperature.
Robustness of Residual Stresses in Brake Discs by Metamodeling
Authors: Hofwing M.
Published: June 2012

During casting residual stresses are developed due to the solidification and cooling. In this work the robustness of residual stresses in casted brake discs with respect to variations in four parameters is evaluated. The parameters are Young’s modulus, yield strength and hardening, time of breaking the mould and the thickness of the brake disc. The robustness analysis is performed by Monte Carlo simulations of metamodels which are surrogates to a finite element model. Quadratic response surfaces and Kriging approximations are considered. Those are based on finite element analyses defined by a Latin hypercube sampled design of experiments. In the finite element analyses an un-coupled approach is utilized where a thermal analysis generates a temperature history of the solidification and cooling. Then follows a structural analysis which is driven by the temperature history. After casting the machining of the brake disc is analyzed by gradually removing elements in the finite element model. The results show that the variation in the studied parameters yield large variation in residual stresses. The thickness of the brake disc is the parameter that has largest influence to the variation in residual stresses. Furthermore, the level of the residual stresses are in general high and might influence the fatigue life of the brake disc.