bluuebunny/crossref_metadata_2025 huggingface dataset:
Five-Axis Manufacturing Simulation Based on Normal Arc Mapping and Offset Volume Computation
Authors: Li Yongqiang , Chen Yong
Published: March 2011

This paper presents a general manufacturing simulation method for 5-axis manufacturing processes including both numerical controlled (NC) machining and additive manufacturing (AM). The method is based on three major steps: (1) normal arc mapping that is general for computing critical curves, (2) computing the cutter swept volume (SCV) along a 5-axis tool paths based on the critical curves, and (3) computation of simulation results based on a set of sampling points from the cutter swept volume. The first two steps are discussed in details. Based on the properties of the envelop theory, we first present a normal arc mapping method that is general and intuitive. Accordingly the critical curves can be computed for any position and orientation of a tool on a 5-axis tool path. We test various tool shapes including three typical cutters in NC machining and a laser ellipsoid tool in Stereolithography apparatus (SLA). Based on the critical curves, the envelope surfaces of the cutter swept volume related to given tool motions can be determined. We compute a closed continuous surface to approximate the cutter swept volume. The approximation error in computed result has been analyzed. Finally we use a discrete representation, layered depth normal images (LDNIs), to convert a set of cutter swept volumes into a booleaned solid model. The discrete computation based on LDNIs enables us to compute the simulation result robustly and effectively. We demonstrate our method for both NC machining and additive manufacturing processes. Five-axis tool paths can also be given in both curves and surfaces. Various test cases have been presented to illustrate the effectiveness of our method.
Mechanics of a Fluid Filled Everting Toroidal Robot for Propulsion and Going Through a Hole
Authors: Orekhov Viktor , Yim Mark , Hong Dennis
Published: March 2011

Whole Skin Locomotion (WSL) is an amoeba inspired locomotion mechanism for mobile robots in which an elongated torus turns itself inside out in a single continuous motion. Since the entire surface is used as a traction surface, WSL has the potential to traverse highly unstructured terrain, and when filled with fluid with an elastic membrane skin, it has the potential to squeeze through holes smaller than its nominal diameter. Previous work has investigated the mechanics of a concentric solid tube (CST) model in which motion is generated by expanding and contracting actuator rings pushing and pulling the membrane around a solid inner tube. In this paper, we present the mechanics of a fluid filled toroid (FFT) model which replaces the solid inner tube with incompressible fluid. Locomotion using contracting ring actuation is described for the FFT model and compared to the CST model. A novel actuation scheme which exploits the chemo-mechanics of soft polymeric elastic skin is also introduced to elicit useful locomotive behavior. Chemically induced swelling in polymeric skin is demonstrated to be a viable propulsion mechanism for a toroidal membrane under pressure. Finally, preliminary analysis is presented for finding forces required for a WSL robot to squeeze through a hole of a given depth and diameter to investigate the feasibility of using contracting ring actuation and chemically induced swelling for hole traversal.
An Investigation of Sustainability, Preference, and Profitability in Design Optimization
Authors: MacDonald Erin , Whitefoot Katie , Allison James T. , Papalambros Panos Y. , Gonzalez Richard
Published: March 2011

Customer preferences for sustainable products are dependent upon the context in which the customer makes a purchase decision. This paper investigates a case study in which fifty-five percent of survey customers say they prefer recycled paper towels, but do not purchase them. These customers represent a profit opportunity for a firm. This paper explores the impact of investing capital in activating pro-environmental preferences on a firm’s profitability and greenhouse gas (GHG) emissions through a multi-objective optimization study. A product optimization is designed to include models of carbon dioxide emissions, manufacturing costs, customer preference, and technical performance. Because the optimization includes a tradeoff between recycled paper and performance, a model of customer preferences, and a market of competing products, the maximum GHG reduction occurs at less than 100% recycled paper. Also, the tradeoff between GHG reductions and profit is not dictated by the configuration of the product, but instead by its price. These results demonstrate the importance of including customer preferences with engineering performance in design optimization. Investment in the activation of pro-environmental preferences is high at all points on the Pareto optimal frontier, suggesting that further engineering design research into the activation of pro-environmental product preferences is warranted.
Supporting Biomimetic Design by Embedding Metadata in Natural-Language Corpora
Authors: Ke J. , Chiu I. , Wallace J. S. , Shu L. H.
Published: March 2011

Biology is a good source of analogies for engineering design. One approach of retrieving biological analogies is to perform keyword searches on natural-language sources such as books, journals, etc. A challenge in retrieving information from natural-language sources is the potential requirement to process a large number of search results. This paper describes how inserting metadata such as part-of-speech, word sense and lexicographical data for each word in a natural-language source can help users identify relevant biological stimuli for biomimetic design. Although this research is still exploratory, initial qualitative observations demonstrate successful identification and separation of biological phenomena relevant to either desired functions or desired qualities. In addition, by incorporating the aforementioned metadata, we can automatically remove search results where search keywords act on abstract nouns or where keywords are used in irrelevant senses. The benefits of embedding metadata are demonstrated through a case study on the redesign of a fuel cell bipolar plate. In this case study, our method can be used to hide 64% of the search results that are unlikely to contain useful biological phenomena, reducing the effort to systematically identify relevant biological analogies.
Multi-Substrate Burrowing Performance and Constitutive Modeling of RoboClam: A Biomimetic Robot Based on Razor Clams
Authors: Winter Amos G. , Deits Robin L. H. , Dorsch Daniel S. , Hosoi A. E. , Slocum Alexander H.
Published: March 2011

The Atlantic razor clam (Ensis directus) reduces burrowing drag by using motions of its shell to fluidize a thin layer of substrate around its body. We have developed RoboClam, a robot that digs using the same mechanisms as Ensis, to explore how localized fluidization burrowing can be extended to engineering applications. In this work we present burrowing performance results of RoboClam in two distinctly different substrates: ideally granular 1mm soda lime glass beads and cohesive ocean mudflat soil. Using a genetic algorithm to optimize RoboClam’s kinematics, the machine was able to burrow in both substrates with a power law relationship between digging energy and depth of n = 1.17. Pushing through static soil has a theoretical energy-depth power law of n = 2, which means that Ensis-inspired burrowing motions can provide exponentially higher energy efficiency. We propose a theoretical constitutive model that describes how a fluidized region should form around a contracting body in virtually any type of saturated soil. The model predicts fluidization to be a relatively local effect, extending only two to three characteristic lengths away from the body, depending on friction angle and coefficient of lateral earth pressure, two commonly measured soil parameters.
Sustainable Product Development Initiatives in the Footwear Industry Based on the Cradle to Cradle Concept
Authors: Jacques Jocelise J. , Agogino Alice M. , Guimara˜es Lia B. M.
Published: March 2011

Following organic processes in nature, the “cradle to cradle” concept sees the waste of a given process as raw material for another. According to this concept, products must be designed in such a way that, in the end of their service life, they can be reused without loss of quality (as technical nutrients) or returned to the environment as biological nutrients and safely decomposed. The main issues, however, are how to move away from the traditional linear system of production (“cradle to grave”) into a cyclic “cradle to cradle” concept, and the identification of parameters that should be considered during the design process in order to achieve real sustainable characteristics through sustainable design and development. The paper provides a review of research and data collection associated with the footwear industry, whose products satisfy a basic human need and are ubiquitous worldwide. After going through a dramatic change in its business model over the last few decades with the advent of outsourcing, today this industry has large economic and environmental impact, highly centralized manufacturing and a complex supply chain, in addition to early but notable efforts on green product development — characteristics that make it a compelling industry to study.
Motorcycle Dynamics in Virtual.Lab Motion
Authors: Moreno Giner David , Toso Alessandro , Cofelice Nicola , Kang Jian
Published: March 2011

Multibody dynamics is an important tool for virtual prototyping of Powered Two Wheelers (PTW), where it can be very useful to analyze/predict their behavior. However, the development of the multibody model and the definition of the different simulation cases are often very time consuming. With the aim of reducing the time of the simulation process, a new set of tools called “Virtual.Lab Motorcycle” has been developed in the multi-body dynamics code LMS Virtual.Lab Motion. A graphic interface allows the user to easily create a motorcycle model. By substituting the tire/ground contact with actuators, the user can also set up a virtual test rig for ride, comfort, durability analysis and reverse load-identification. The application provides the possibility to simulate the motorcycle response both on the road and on the virtual test rig. The interface and the main structure of the application are explained here and first results are presented.
iTrain: Ontology-Based Integration of Information and Methods in Computer-Based Training (CBT) and Immersive Training (IMT) for Assembly Simulations
Authors: Kim OkJoon , Jayaram Uma , Jayaram Sankar , Zhu Lijuan
Published: March 2011

Training for assembly simulations can be provided using a wide range of technologies — from a simple computer-based training (CBT) approach to a complex immersive training (IMT) approach. The CBT approach allows user interactions through traditional keyboard and mouse while the IMT approach immerses the user in a virtual environment for a more realistic experience. Typically, for a particular scenario, tools for each of these are developed completely independently. Consequently, there is much duplication of data and effort and a lack of synchronization between them. In this paper, we focus on ontologies for the assembly simulation and training domain. Ontologies provide an opportunity to capture and manage common data and map concepts from one application to another in a logical and measured manner. Methods are developed to enable knowledge in these ontologies to be used and shared in a comprehensive and effective manner between CBT and IMT tools. Both tools are also well integrated with the Sharable Content Object Reference Model (SCORM) so that the progress during training can be recorded, tracked and evaluated by Learning Management System (LMS).
Coupled Field Damage Dynamics via Hamilton’s Principle
Authors: Cusumano Joseph P. , Li Qiang
Published: March 2011

We present a new coupled-field model for the dynamics of systems with evolving damage. The continuum model is developed using Hamilton’s Principle together with Griffith energy arguments, and captures the interaction between a meso-scale damage field variable and macroscopic vibrational displacements. The method of averaging is used to show that the nonautonomous coupled-field model gives the autonomous Paris’ Law as a special case.
Concept Study of a Passive Reduced-Gravity Simulator for Training Astronauts
Authors: Ma Ou , Lu Qi , McAvoy Jesse , Ruble Ken
Published: March 2011

Each manned space exploration mission requires a significant amount of microgravity or reduced-gravity (physical) simulation before the mission to train astronauts and verify some mission requirements. An appealing new simulation technique for such an application must be effective, safe, and inexpensive. This paper presents a novel design concept of a reduced-gravity simulator for simulating human walking in a controllable reduced-gravity condition. Designed based on the spring-based passive gravity-balancing technology, the 3D passive reduced-gravity simulator has sufficient mobility to allow the attached human to walk while feeling less gravity effects. The system is completely passive and thus, it is intrinsically stable, safe and cost effective. A concept study of the new mechanism using multibody dynamics simulations including a full-scale human dynamics model has demonstrated the effectiveness of the device for offloading any desired amount of gravity force. A scaled-down nonhuman experimental test using a walking robot and a passive jump device is currently underway.
Use of Neural Networks in Road Recognition by Vibration Data
Authors: Reggiani Giacomo , Cocconcelli Marco , Rubini Riccardo , Lolli Francesco
Published: March 2011

This paper deals with road recognition by the use of neural networks on vibration signals. In particular, an accelerometer sensor is used and it acquires the vibrations transmitted in the contact between the tyres and the ground. Twelve different types of road have been tested at different speed of the car. Based on these data a neural network has been proposed to correlate a set of suitable characteristics of the vibration signal with the type of road. The effectiveness of the resulting neural network has been proved on a control set of data. Moreover the paper reports a sensitivity analysis of the neural network in order to minimize the number of inputs needed and to make it rugged.
A Hybrid Biomimetic Genetic Algorithm Using a Local Fuzzy Simplex Search
Authors: Ladkany George S. , Trabia Mohamed B.
Published: March 2011

This paper presents a hybrid genetic algorithm that expands upon the previously successful approach of twinkling genetic algorithm (TGA) by incorporating a highly efficient local fuzzy-simplex search within the algorithm. The TGA was in principle a bio-mimetic algorithm that introduced a controlled deviation from a typical GA method, by not requiring that every genevariable of an offspring be the result of a crossover. Instead, twinkling allowed the genetic information of the randomly chosen gene locations to be directly passed on from one parent, which was shown to increase the likelihood of survival of a successful gene value within the offspring, rather than requiring it to be blended. The twinkling genetic algorithms proved highly effective at locating exact global optimum with a competitive rate of convergence for a wide variety of benchmark problems. In this work, it is proposed to couple the TGA with a fuzzy simplex local search to increase the rate of convergence of the algorithm. The proposed algorithm is tested using common mathematical and engineering design benchmark problems. Comparison of the results of this algorithm with earlier algorithms is presented.
Evolution of Design for X Tools Applicable to Design Stages: A Literature Review
Authors: Chiu Ming-Chuan , Okudan Gu¨l E.
Published: March 2011

Design stage is very critical as many decisions impacting the downstream development activities and the product cost are made in this stage. Over the years, numerous “Design for X (DfX)” concepts/methods have been developed in order to increase the efficiency at the design stage, and reduce the total product cost and development lead time. Design for manufacture, assembly, quality, maintenance, environment, obsolescence and recyclability, etc. are among these. Despite the availability of these numerous concepts/methods, a “big picture” to illustrate the relations and the interactions among these X factors remains absent. In the paper, we attempt to provide our version of this “big picture” along with maturity and trajectory of these factors as identified from the published literature.
Contouring of Structured Points With Small Features
Authors: Chen Yong , Wang Charlie C. L.
Published: March 2011

As one type of structured points, the layered depth-normal images (LDNIs) is a discrete representation of solid models. It uses sampling points to sparsely encode the shape boundary in three orthogonal directions. Geometric modeling operations on the LDNIs solids can be performed robustly and easily. However, it is generally challenging to faithfully reconstruct the boundary representation (B-Rep) from the LDNIs solid especially for features whose sizes are close to the resolution of sampling points. In this paper, we present a novel contouring method to generate boundary surfaces from a LDNIs solid. In our method, we first consistently classify the inside/outside status of all the nodes and accordingly verify the Hermite data of sampling points. We then individually construct a set of contour edges on each cell face. We illustrate that complex shells can be more easily handled by using the approach of constructing contour edges. In addition, we develop simple and effective approaches to address the topology ambiguity cases that are typical in the contouring process. By forming the contour edges into contour loops, we can construct 2-manifold polygonal mesh surfaces for the LDNIs solid. Compared to other contouring methods, the proposed method can faithfully capture all the features that are 1-dimensionally smaller than the sampling resolution. We report experimental results on a variety of CAD models.
A Small to Medium-Size Enterprise Oriented Methodology for Optimizing Product and Supply Chain Design Decisions
Authors: Chiu Ming-Chuan , Okudan Gu¨l E.
Published: March 2011

Today supply chain management has become one of the crucial factors for gaining and sustaining a competitive advantage. Enterprises that can more effectively manage their supply chain network have a higher likelihood of success in the marketplace. To this end, companies need not only make the “make” or “buy” decisions but also differentiate across potential suppliers in order to improve operational performance, and hence, supplier selection is one of the key decisions aiding effective supply chain management. Many studies have also pointed out that the integration of product and supply chain is a key factor for profitability and efficiency. However, prior studies mostly address supply chain performance after the creation of a new product; and only a few studies discuss when and how to incorporate supply chain decisions during product design. In the studies that cover product design, product family and product platform concepts are presented as enabling vehicles for mass customization, which require a considerable investment, and hence might be out of reach for small to medium size enterprises (SME). Accordingly, there is a need to develop a methodology that can consider manufacturability and supply chain issues at the product design stage. This paper presents a graph theory based optimization methodology to tackle this problem. The supplier selection issue is considered by evaluating its impact on both engineering (e.g., process planning) and operational performance (e.g., cost and time), which are then aggregated as the supply chain performance at the conceptual design stage. A case study in the bicycle industry demonstrates the advantages of this methodology. The synchronized structure of the supply chain and the product design results in simultaneous optimization of both design and supply chain decisions during the early design stages.
Automatic Function Interpretation: Using Natural Language Processing on Patents to Understand Design Purposes
Authors: Li Zhen , Tate Derrick
Published: March 2011

In engineering design, establishing functional requirements (FRs) based on customer needs (CNs) is critical to ensure the success of a product. However, it may take a lot of time for a designer to state functional requirements explicitly. To overcome this difficulty, the authors have proposed a method to interpret design intention in accordance with the axiomatic design (AD) framework by applying natural language processing (NLP) techniques on patents. The goal of the proposed method is to provide functional requirements and design parameters that are automatically extracted for designers. Although the initial result shows that the method is dependent on the writing style used in a patent, this fresh attempt demonstrates the feasibility of automatically interpreting design intention.
Spatial Generalizations of Planar Point-Angle and Path Generation Problems
Authors: Huang Chintien , Lai Ching-Lung
Published: March 2011

This paper deals with the spatial generalizations of two classical planar synthesis problems: the point-angle and path generation problems. The two planar synthesis problems involve the guidance of a point through specified positions by using planar four-bar linkages. In spatial generalizations, we are concerned with the guidance of a line by using spatial 4C linkages. The equivalent screw triangle is employed to derive the synthesis equations of the spatial 4C linkage. The synthesis of the RCCC linkage is achieved by constraining the translational motion in the driving C joint. Our results show that the synthesis of the 4C linkage for line guidance yields the same maximum number of positions as the planar 4-bar linkage for point guidance. The maximum number of positions of the path generation of a line is nine, while that of the lineangle problem is five. In addition to presenting the spatial generalizations of planar synthesis problems, the results provided in this paper can be used to design spatial four-bar linkages to match line specifications, in which only an infinitely-extended line, such as a laser beam, is of interest.
Selection of Vehicle Architecture for EcoCAR Competition Using Axiomatic Design Principles
Authors: Tate Derrick , Maxwell Timothy T. , Sharma Bharatendra S. , Patil Kunal
Published: March 2011

Axiomatic design (AD) techniques have not previously been applied in designing the overall architecture of an automobile. The present work investigates use of axiomatic design concepts for vehicle design in the Texas Tech University Eco-CAR program. The three different architectures considered are fuel cell, two-mode hybrid, and belt alternator/starter system (BAS+). The objective in using axiomatic design methods is to choose an architecture for the EcoCAR competition vehicle that follows the principles of axiomatic design, and in turn, should prove to be the best choice of vehicle architecture among the three considered. Function means trees (FMT) and design matrices (DM) are constructed for each of the architectures and are used in deciding whether the architecture is a coupled, uncoupled, or decoupled design per the independence axiom. The choice is supported by means of simulation results obtained for each architecture. Finally, a two-mode hybrid architecture is selected based on the use of axiomatic design and the simulation results.
A New Fatigue Testing Apparatus Model and Parameter Identification
Authors: Falco Michael , Liu Ming , Chelidze David
Published: March 2011

Recently, a novel fatigue testing rig was designed and constructed to investigate the interplay between a fatigue crack evolution and structural dynamics. The aim of this study is to build a simple nonlinear spring-mass-damper model for this testing apparatus and identify all related parameters. A set of forced vibration tests were conducted with different hardware configurations and excitation signals to understand dynamic properties of different components of the rig and present nonlinearities. The system parameters were identified using standard modal analysis and nonlinear system identification approaches.
Empathic Design for Early-Stage Problem Identification
Authors: Ciavola Benjamin , Ning Yan , Gershenson John K.
Published: March 2011

This paper promotes a user-centered design approach known as empathic design in which special emphasis is placed on observation of the affective nature of user-product relationships. Through empathic observation in real-world contexts, designers can come to understand end users’ emotional reactions to a product on multiple cognitive levels, including the customer’s true latent goals and desires. From these observations, there is an opportunity to better interpret how the design problem arises from actual user experiences. In this paper, we begin construction of a systematic framework for empathic design, and propose the development of a methodological toolbox for use within the scope of traditional design processes. Problem identification is reframed to aid in identification of hidden and latent customer needs through awareness of distinct levels of implicit and explicit cognitive processing and evaluation. This approach is meant to help designers better understand the root cause of user behavior and affective response to a product. Additionally, a number of types of supporting design tools are identified, and promising areas of future development are discussed.
Product Family Design Through Customer Perceived Utility
Authors: Kim Tae-Hyun , Okudan Gu¨l E. , Chiu Ming-Chuan
Published: March 2011

Even though functional characteristics and various forms can be measured directly and objectively, many designers and engineers still fail to clearly evaluate product criteria due to consumers’ subjective inputs, which change over time. To appropriately evaluate product criteria, an effective design decision making analysis is required. In this study, we propose a methodology to assure this harmony using a mobile phone product family design scenario. Customer perceived utility of design features are first gathered using a questionnaire (with more than 500 responses), and then modeled using multi-attribute utility theory (MAUT) to allow for clustering based on consumer demographics (e.g., race, gender, and age). Based on the clustering, several mobile phone models are tested for their fitness. The goal of the methodology is to determine the appropriate product family size in order to satisfy customer needs as well as reduce supply chain complexity.
Application of Particle Swarm Optimization to Robot Path Planning Problem
Authors: Kobayashi Masakazu , Masatake Higashi
Published: March 2011

A robot path planning problem is to produce a path that connects a start configuration and a goal configuration while avoiding collision with obstacles. To obtain a path for robots with high degree of freedom of motion such as an articulated robot efficiently, sampling-based algorithms such as probabilistic roadmap (PRM) and rapidly-exploring random tree (RRT) were proposed. In this paper, a new robot path planning method based on Particle Swarm Optimization (PSO), which is one of heuristic optimization methods, is proposed in order to improve efficiency of path planning for a wider range of problems. In the proposed method, a group of particles fly through a configuration space while avoiding collision with obstacles and a collection of their trajectories is regarded as a roadmap. A velocity of each particle is updated for every time step based on the update equation of PSO. After explaining the details of the proposed method, this paper shows the comparisons of efficiency between the proposed method and RRT for 2D maze problems and then shows application of the proposed method to path planning for a 6 degree of freedom articulated robot.
Response Surface Based Cost Model for Onshore Wind Farms Using Extended Radial Basis Functions
Authors: Zhang Jie , Chowdhury Souma , Messac Achille , Castillo Luciano , Lebron Jose
Published: March 2011

This paper develops a cost model for onshore wind farms in the U.S.. This model is then used to analyze the influence of different designs and economic parameters on the cost of a wind farm. A response surface based cost model is developed using Extended Radial Basis Functions (E-RBF). The E-RBF approach, a combination of radial and non-radial basis functions, can provide the designer with significant flexibility and freedom in the metamodeling process. The E-RBF based cost model is composed of three parts that can estimate (i) the installation cost, (ii) the annual Operation and Maintenance (O&M) cost, and (iii) the total annual cost of a wind farm. The input parameters for the E-RBF based cost model include the rotor diameter of a wind turbine, the number of wind turbines in a wind farm, the construction labor cost, the management labor cost and the technician labor cost. The accuracy of the model is favorably explored through comparison with pertinent real world data. It is found that the cost of a wind farm is appreciably sensitive to the rotor diameter and the number of wind turbines for a given desirable total power output.
Knowledge-Based Task Planning Using Natural Language Processing for Robotic Manufacturing
Authors: Mantegh Iraj , S. Darbandi Nazanin
Published: March 2011

Robotic alternative to many manual operations falls short in application due to the difficulties in capturing the manual skill of an expert operator. One of the main problems to be solved if robots are to become flexible enough for various manufacturing needs is that of end-user programming. An end-user with little or no technical expertise in robotics area needs to be able to efficiently communicate its manufacturing task to the robot. This paper proposes a new method for robot task planning using some concepts of Artificial Intelligence. Our method is based on a hierarchical knowledge representation and propositional logic, which allows an expert user to incrementally integrate process and geometric parameters with the robot commands. The objective is to provide an intelligent and programmable agent such as a robot with a knowledge base about the attributes of human behaviors in order to facilitate the commanding process. The focus of this work is on robot programming for manufacturing applications. Industrial manipulators work with low level programming languages. This work presents a new method based on Natural Language Processing (NLP) that allows a user to generate robot programs using natural language lexicon and task information. This will enable a manufacturing operator (for example for painting) who may be unfamiliar with robot programming to easily employ the agent for the manufacturing tasks.
Topologically Enhanced Slicing of MLS Surfaces
Authors: Yang Pinghai , Li Kang , Qian Xiaoping
Published: March 2011

Growing use of massive scan data in various engineering applications has necessitated research on point-set surfaces. A point-set surface is a continuous surface defined directly with a set of discrete points. This paper presents a new approach that extends our earlier work on slicing point-set surfaces into planar contours for rapid prototyping usage. This extended approach can decompose a point-set surface into slices with guaranteed topology. Such topological guarantee stems from the use of Morse theory based topological analysis of the slicing operation. The Morse function for slicing is a height function restricted to the point-set surface, an implicitly defined moving least-squares (MLS) surface. We introduce a Lagrangian multiplier formulation for critical point identification from the restricted surface. Integral lines are constructed to form Morse-Smale complex and the enhanced Reeb graph. This graph is then used to provide seed points for forming slicing contours, with the guarantee that the sliced model has the same topology as the input point-set surface. The extension of this approach to degenerate functions on point-set surface is also discussed.
EMD, Ranking Mutual Information and PCA Based Condition Monitoring
Authors: Zhao Xiaomin , Zuo Ming J. , Patel Tejas
Published: March 2011

Success of any health monitoring system chiefly relies on the effectiveness of condition monitoring parameter. The parameter could be a single or combination of many vibration features. These features are expected to have a monotonic trend with the damage/fault progression. Ranking mutual information technique has the ability to detect the features that have monotonic trend and PCA is a popular and widely accepted multidimensional analysis tool for the feature fusion. A condition monitoring method is presented in this paper by combining EMD, ranking mutual information and PCA. The proposed method is helpful in generation of the indicator that represents the damage progression. This method is tested on the impeller health condition monitoring of a pump.
Sensitivities Analysis Using the Semi-Analytic Complex Variable Method in Fracture Mechanics
Authors: Jin Weiya , Dennis Brian H. , Wang Bo Ping
Published: March 2011

In fracture mechanics, due to singularity existing on the crack tip, the corresponding sensitivity analysis of Stress Intensity Factor (SIF) is not clear whether the overall finite difference (OFD) or Semi-analytical Method (SAM) can obtain accurate sensitivities. The paper proposes the Semi-analytical Complex Variable Method (SACVM) to compute sensitivities of SIF and compares the sensitivities computed by the SACVM with those computed by the OFD and SAM in Center Cracked Tension (CCT) specimen and Single Edge Notched Tension (SENT) specimen. The results reveal that the OFD obtains oscillated sensitivities because of the ill-conditioned linear system. The sensitivities computed by the OFD and SAM are sensitive to the perturbation size out of a certain range. However, this certain range varies with different variable, and is not known a priori. The proposed SACVM can always obtain accurate, consistent sensitivities with little extra computational cost than the SAM. The SACVM is not sensitive to the perturbation size and is not affected by the ill-conditioned linear system. Therefore, the SACVM is recommended to deal with sensitivity analysis in the fracture mechanics.
Analysis of Multi-Threaded Code Execution on Small Multi-Core Architectures
Authors: Sgroi Kevin J. , Spetka Scott E.
Published: March 2011

Utilizing threads and other parallel execution techniques efficiently to achieve concurrency on multiple processors/cores is becoming more difficult as the complexity of engineering applications increases. While hardware performance and scalability in this environment have been well-studied, software and operating system aspects of parallel code execution deserve additional attention. This is especially the case for smaller multi-core architectures such as those found in desktop computers. A matrix-multiply application has been customized to generate a multi-threaded load for testing, to address issues associated with mixing a multi-threaded load with available Linux benchmarking tools. This application was executed with the UNIXBENCH benchmark test suite in this study to conduct experiments designed to reveal problem areas that should be considered when implementing applications on modern parallel computing architectures. The analysis covers five types of operations: CPU intensive, Inter-process communication with pipes, shell script execution, file I/O and System call overhead. The results indicate that shell script execution, file I/O and system call overhead had the most degradation in performance as the multi-threaded load was increased. Pipe-based communication (directly between processes) and CPU intensive operations tended to scale well as the load increased.
Incorporating Cost and Resource Efficiency Into the Development of Green Recycling Technologies
Authors: Yang Q. Z. , Qi G. J. , Low H. C.
Published: March 2011

The development of cost-effective and green recycling technologies for secondary metal recovery from industrial wastes is one of the new challenges on the sustainable development agenda. By incorporating cost and resource efficiency assessment into the technology innovation process, we aim to improve the sustainability of new recycling technologies by minimizing process waste, improving resource efficiency, thus reducing the recovery process cost. This paper focuses on modeling and assessing the production cost and resource use efficiency for closed-loop nickel recovery from spent hydrogenation catalysts. The engineering economics factors and process variables that affect the profitability and resource efficiency of nickel recovery are identified. They are modeled in cost and efficiency metrics. Model-based scenarios assessment revealed that compared to open-loop nickel recovery, the closed-loop concept delivers more cost-effective and greener recycling solutions. The closed-loop process cost reduction via efficient resource use and process waste minimization is in the range of 18.4% to 24.0% compared to the open-loop process option.
Electro-Mechanical Coupling of Piezoelectric Nanocomposites
Authors: Chen Xi , Xu Shiyou , Shi Yong
Published: March 2011

Energy harvesting technology that can increase the operation time and decrease the device size is urgently needed in wireless electronics, portable devices, and implantable biosensors. This paper reports the experimental study of electromechanical coupling of PZT (piezoelectric) nanofiber composites which have the potential to be used for energy harvesting. The recorded voltage output was about 6 mV in the experiments. In this paper, we will describe the fabrication of the piezoelectric nanocomposites and demonstrate the characteristics of electro-mechanical coupling using a dynamic mechanical test. The piezoelectric nanocomposite assembly could produce high voltage and power output to be used as a power source, which might be used for wireless sensors, personal electronics, implantable bio-sensors, and bio-actuators.
Screw Systems Generated From Subalgebras: Properties and Applications
Authors: Rico J. M. , Cervantes-Sa´nchez J. J. , Tadeo-Cha´vez A. , Pe´rez-Soto G. I.
Published: March 2011

The contribution presents the properties and applications of screw systems generated from the addition of subalgebras of the Lie algebra, se(3), of the Euclidean group, SE(3). It is shown that these screw systems have important properties related with the mobility of kinematic chains formed with these screw systems.
An Effective Approach to Approximating 2-D Free-Form Curve Offsets for B-Spline NC Tool Paths With Offset Error Globally Bounded
Authors: Khan Maqsood A. , Chen Zezhong C.
Published: March 2011

The topic of representing the offset of a 2-D B-spline curve in the same form has been under research for a long time, and it has many industrial applications, especially, in NC tool path generation for pocketing. For B-spline tool paths, it is often required that the tool paths have fewer control points, lower base function degree, and higher geometric accuracy. However, the existing methods often generate the offsets of 2-D free-form curves in the form of B-spline curves with high function degree and many control points. Although these offsets are useful in computer-aided design, they are inappropriate for the use of CNC machining. To address the problems in order to generate high quality B-spline tool paths, this original work formulates an error function of the offset approximation and then constructs a NURBS curve to globally bound the errors. By checking the maximum coefficient of the bounding curve, the upper bound of all the approximated offset errors is found and the errors can be reduced by adding more offset points at the appropriate locations. The proposed new approach is more efficient, and the resulting offsets in B-spline are more accurate with fewer control points and lower function degree. It is useful to generate B-spline tool paths for CNC pocketing, and has potential for other applications in industry.
Sparking a Lifelong Interest in Engineering Through a Summer Academy in Robotics
Authors: Ayanian Nora , Keller James F. , White Paul J. , Kumar Vijay
Published: March 2011

We have developed an intensive, three-week summer robotics program for high school students. The program requires special teaching methods since it is offered to rising 10th through 12th grade students with diverse backgrounds, and a low student/teacher ratio to ensure all students grasp the material. We use a project-based learning approach, assigning the students a series of specially tailored labs and projects designed to engage and challenge while preparing them for the main element of the program, the design of a semi-autonomous robotic vehicle whose mission emulates that of NASA’s Martian rovers. The project culminates with testing of their vehicles on an obstacle course. A series of targeted design reviews are held as the project unfolds to keep all designs on schedule. We leverage the spirit of competition to heighten the enthusiasm of the students and sustain their interest through the long-hours required to design and build a successful robot. The students get hands-on experience with mechanism design, electronics, computer-aided-design and manufacturing, and microprocessor programming, and are engaged in discussions on applications of robotics in both academia and industry to provide a “grounding” of the material.
Simulation Studies on the Influence of Obstacle on Rolling Lunar Wheel
Authors: Ma Jianfeng , Summers Joshua David , Joseph Paul F.
Published: March 2011

In order to investigate the influence of the road obstacles on the performance of the non-pneumatic tire, Finite Element Method (FEM) is utilized to model and simulate the dynamic impact of the obstacles on the running non-pneumatic tire. The non-pneumatic tire consists of three major components: two inextensible circumferential membranes, a critical shear beam, and deformable spokes. The non-pneumatic tire fabricated of segmented cylinders is illustrated and the FEM model of pneumatic tire is presented in detail. The tire is treated as an elastic deformable body and the inertial effect is included. The road and obstacle is represented as analytical rigid bodies. The effects of obstacle height, obstacle fillet radius, and tire running speed are presented.
Methodology to Support Environmentally Aware Product Design Using Axiomatic Design: eAD+
Authors: Shin Mijeong , Morrison James R. , Suh Hyo Won
Published: March 2011

With the increasing environmental sophistication of consumers, there is a need to consider environmental factors and sustainability in the design process. This paper proposes a design methodology intended for software implementation called eAD+ to address the following four issues: 1) there are inherent couplings between eco-factors and product design parameters, 2) eco-factors are seldom structured for ready use within all phases of the design process, 3) there is a need for a formal feedback mechanism from the results of eco-analysis to the design process, and 4) it can be difficult to identify which design choice causes the most egregious environmental issue or functional coupling. eAD+ is based primarily on the Axiomatic Design (AD) methodology and addresses these issues as follows. First, AD directly identifies couplings between the functional requirements (FRs) in a design so that efforts, such as TRIZ, can be applied to address them. Second, as common eco-factors do not provide sufficient structure for inclusion in the AD framework, we develop structured eco-FRs and constraints. These are included alongside the product FRs throughout the design process. Third, the subset of the design matrix (DM) relating the eco-FRs to the design parameters explicitly incorporates feedback from eco-analysis into the design process. Here a database containing environmental (or sustainability) information is employed to evaluate the design. Fourth, we employ an augmented DM (drawing inspiration from the House of Quality of QFD) that provides weights highlighting which design parameter has the greatest influence on eco-factors and functional couplings.
On a Solution Procedure to Synthesize Non-Smooth Path Generating Compliant Mechanisms With Self Contact
Authors: Reddy B. V. S. Nagendra , Saxena Anupam
Published: March 2011

A contact-aided compliant mechanism (CCM) is a single piece flexible continuum that uses the contact interactions between different portions in addition to the elastic deformation. Our work deals with the design of contact aided compliant mechanisms with initially curved frame elements to trace more complex and non smooth paths. We can achieve these kinematic tasks by using partially compliant mechanisms as well. But the presence of hinges is a disadvantage in terms of increased friction, backlash, need for lubrication, noise and vibrations. In this paper, we propose an automated procedure to obtain the optimum design of large deformation CCMs. Through commercial software, we simulate the formation of pseudo hinges at contact sites that get formed dynamically as the mechanism deforms. By appropriately positioning these pseudo hinges, i.e., by designing a suitable CCM, the aim, in general, is to achieve a variety of function, path and motion generation characteristics via single piece continua.
Processes That Enable the Development of Production Control Systems for Hybrids/Alternative Energy Vehicles
Authors: Ramaswamy Deepa
Published: March 2011

There are several challenges involved in the development of a production control system for a hybrid/alternative energy vehicle. Some of the challenges center around the new component technologies such as batteries, power electronics, electric machines or hydraulics that are an integral part of such a vehicle. Others center around the invention that is required to develop novel algorithms that utilize these component technologies in the most synergistic fashion with conventional technologies so as to optimize a cost function of interest (fuel economy for example). While these challenges are noteworthy in their own right, there are additional challenges that need to be overcome to actually bring them to production and to deliver a quality product that meets the OEM requirements for quality and robustness over the lifetime of the vehicle (10 years/150,000 miles for example). These hybrid/alternative energy production vehicles are expected to be exercised in the very same environments (e.g. hot, cold, high altitude, humid) that the consumer has been using conventional vehicles in. This paper describes several processes that enable the development of control systems that can not only “get things working”, but also meet the more rigorous quality and robustness demands imposed upon a production vehicle. While these processes are not limited in their usage to only hybrid/alternative energy vehicles, it is the newness of the technologies in these vehicles, and the need to respond rapidly to the needs of the marketplace that really necessitates the use of such processes on these types of vehicles.