bluuebunny/crossref_metadata_2025 huggingface dataset:
Concepts in Biomimetic Design: Methods and Tools to Incorporate Into a Biomimetic Design Course
Authors: Glier Michael W. , McAdams Daniel A. , Linsey Julie S.
Published: June 2012

Biomimetic design, the use of nature to inspire solutions to engineering problems, has been practiced on an ad hoc basis throughout human history. Only recently, however, have researchers sought to develop formal tools and principles to effectively tap the wealth of design solutions found within nature. Texas A&M University is developing an undergraduate course to introduce interdisciplinary engineering students to the current concepts, principles, and methods of biomimetic design, as found in published literature. This paper seeks to concisely present the results and conclusions of the many research efforts that will be incorporated into the developing course. The research reviewed in this paper is discussed with some emphasis on its pedagogical implications. Research efforts in applying design tools such as functional modeling, analogical reasoning, and the Theory of Inventive Problem Solving (TRIZ) to biomimicry are summarized. This paper also discusses the efforts to develop effective tools to search biological information for design inspiration. As similar courses in biomimetic design have been conducted at the Georgia Institute of Technology and the University of Maryland, the published findings from those courses are also presented.
Decomposition Templates and Joint Morphing Operators for Genetic Algorithm Optimization of Multi-Component Topology
Authors: Zhou Zebin , Hamza Karim , Saitou Kazuhiro
Published: June 2012

This paper presents a continuum-based approach for multi-objective topology optimization of multi-component structures. Objectives include minimization of compliance, weight and as cost of assembly and manufacturing. Decision variables are partitioned into two main groups: those pertaining to material allocation within a design domain (base topology problem), and those pertaining to decomposition of a monolithic structure into multiple components (joint allocation problem). Generally speaking, the two problems are coupled in the sense that the decomposition of an optimal monolithic structure is not always guaranteed to produce an optimal multi-component structure. However, for spot-welded sheet-metal structures (such as those often found in automotive applications), certain assumptions can be about the performance of a monolithic structure that favor the adoption of a two-stage approach that decouples the base topology and joint allocation problems. A multi-objective genetic algorithm (GA) is used throughout the studies in this paper. While the problem decoupling in two-stage approaches significantly reduces the size of the search space and allows better performance of the GA, the size of the search space can still be quite enormous in the second stage. To further improve the performance, we propose a new mutation operator based on decomposition templates and localized joints morphing. A cantilever-loaded structure is then used as a metric to study and compare various setups of single and two-stage GA approaches.
On Using Kriging Models for Complex Design
Authors: Martin Jay D.
Published: June 2012

The design of most modern systems requires the tight integration of multiple disciplines. In practice, these multiple disciplines are often optimized independently, given only fixed values or targets for their interactions with other disciplines. The result is a system that may not represent the optimal system-level design. It may also not be a robust design in the sense that small changes in each subsystem’s performance may have a large impact on the system-level performance. The use of kriging models to represent the response surfaces of subsystems that are then combined to estimate system-level performance can be used as a method to provide collaboration between design teams. The difficulty with this method is the creation of the models given potentially large number of dimensions or observations. This paper presents a method to reduce the dimensionality of the input space for kriging models used for designing of complex systems. The input dimensionality of the kriging model is reduced to only includes the most important factors needed for the prediction of the observed output. A result of using these reduced dimensionality models is the need to no longer force interpolation of all of the observations used to create the models.
A Method for Identifying Design Principles for the Developing World
Authors: Campbell Robert D. , Lewis Patrick K. , Mattson Christopher A.
Published: June 2012

Growing awareness of the unique needs and challenges in the developing world has resulted in the development of products for those in poverty. Successful product design focuses development efforts on design principles that are important to a target market. Consequently, the better these principles are understood, the higher the probability is that resulting products will be successful. Recognizing that the identification of these principles is a major challenge, this paper presents a method for identifying them for any target market, but especially for the developing world. The presented methodology uses characteristics of products within the target market to extract information about the underlying design decisions resulting in these characteristics. This information is then used to identify the design principles. To verify the ability of the method to identify these principles, the method is applied to best selling products in the US and then applied to products created for the developing world. The resulting principles from the two markets are then analyzed and compared to highlight the similarities and differences between the identified principles. The authors conclude that the resulting list of principles will enable designers to better design and develop products for the developing world.
Enhancing the Sensitivity of Electrostatically Actuated Resonant Switch for Earthquake Detection
Authors: Ramini Abdallah H. , Younis Mohammad I.
Published: June 2012

Enhancing the sensitivity of an electrostatically actuated resonant switch (EARS) for earthquake detection is investigated. The resonator is proposed to operate close to instability bands of frequency-response curves, where it is forced to pull-in if operated within these bands. By careful tuning, the resonator can be made to enter the instability zone upon the detection of the earthquake signal, thereby pulling-in as a switch. Such a switching action can be functionalized for alarming purposes or can be used to activate a network of sensors for seismic activity recording. By placing such a resonator on a printed circuit board of a natural frequency close to that of the earthquake’s frequency, significant improvement on the detection limit of this switch is achieved. In this work, nonlinear Single-Degree-Of-Freedom (SDOF) and 2-Degree-Of-Freedom (2-DOF) models are used to simulate the performance of the switch concept.
Integration of an Autopilot System With a Hobby RC Helicopter
Authors: Xie Pu , Gardner Bryndan , Ma Ou
Published: June 2012

This paper describes the integration and test work of a small unmanned aerial vehicle (UAV) with autopilot capability, which is currently being developed at New Mexico State University. The UAV is an integration of a commercially available autopilot system (Micropilot’s MP2128HELI) with an RC helicopter (Raptor 90). It has been found quite challenging to integrate an autopilot system with a hobby RC helicopter for research purpose because hobby airframes, as low-cost and manually operated toys, were not designed readily for working with delicate and sensitive autopilot electronics. In our case, the strong vibration disturbances from the gas engine and other moving parts of the airframe significantly corrupted the signals from the avionics hardware. Innovative vibration isolation technique has been developed to mechanically isolate the vibrations from affecting the autopilot system. Several other key problems related to electromagnetic interference shielding and safe flight test were also effectively solved on the project. The integration work has been completed and the UAV is currently being tested.
Design for Patentability (DFP)
Authors: Naidu Prakash C. R. J. , Naidu Kshirsagar C. J.
Published: June 2012

This paper introduces a new approach named Design for Patentability (DFP) and presents the preliminary formulation of a formal methodology to attempt consideration of patentability aspects during the early stages of design including conceptual design and initial implementation of detailed design and manufacturing. Design for Automation (DFAM) approach formulated earlier by the first author based on Axiomatic Design Theory originated by Suh et. al. at MIT is adapted, suitably modified and customized for inclusion of patentability aspects such as anticipation, functionality, utility, and obviousness. Highlighting the complexity in incorporation of legal aspects in an engineering methodology, the paper presents the possibilities of improving the patentability of a design by a systematic and considered approach. The proposed methodology introduces a Patentability Evaluation phase in-between the Product Design, Process Design and Automation System Design phases of DFAM. The paper reviews mapping of parameters between different domains, namely, Functional Requirements Domain, Design Parameters Domain, Process Requirements Domain, and Design Automation Parameters Domain encompassed in the DFAM methodology and includes Patentability Parameters Domain in parallel to the last three domains to enable possible consideration of patentability aspects during Product Design, Process Design, and Automation System Design. Further, the paper briefly discusses the relevance of the Information Axiom of the Axiomatic Design Theory in the context of preparation of preliminary drafts of invention disclosure and potential claims for perusal by patent agents or attorneys. The approach reported in the paper is expected to have broad applications in the growing field of innovation based entrepreneurship in which design for patentability is an essential requirement for success of a business venture.
Bounded Target Cascading in Hierarchical Design Optimization
Authors: Zhang Xiao-Ling , Lin Po Ting , Gea Hae Chang , Huang Hong-Zhong
Published: June 2012

Analytical Target Cascading method has been widely developed to solve hierarchical design optimization problems. In the Analytical Target Cascading method, a weighted-sum formulation has been commonly used to coordinate the inconsistency between design points and assigned targets in each level while minimizing the cost function. However, the choice of the weighting coefficients is very problem dependent and improper selections of the weights will lead to incorrect solutions. To avoid the problems associated with the weights, single objective functions in the hierarchical design optimization are formulated by a new Bounded Target Cascading method. Instead of point targets assigned for design variables in the Analytical Target Cascading method, bounded targets are introduced in the new method. The target bounds are obtained from the optimal solutions in each level while the response bounds are updated back to the system level. If the common variables exist, they are coordinated based on their sensitivities with respect to design variables. Finally, comparisons of the results from the proposed method and the weighted-sum Analytical Target Cascading are presented and discussed.
Design of Compliant Structural Mechanisms Using B-Spline Elements
Authors: Kumar Ashok V. , Parthasarathy Anand
Published: June 2012

Structural design is an inverse problem where the geometry that fits a specific design objective is found iteratively through repeated analysis or forward problem solving. In the case of compliant structures, the goal is to design the structure for a particular desired structural response that mimics traditional mechanisms and linkages. It is possible to state the inverse problem in many different ways depending on the choice of objective functions used and the method used to represent the shape. In this paper, some of the objective functions that have been used in the past, for the topology optimization approach to designing compliant mechanisms are compared and discussed. Topology optimization using traditional finite elements often do not yield well-defined smooth boundaries. The computed optimal material distributions have shape irregularities unless special techniques are used to suppress them. In this paper, shape is represented as the contours or level sets of a characteristic function that is defined using B-spline approximation to ensure that the contours, which represent the boundaries, are smooth. The analysis is also performed using B-spline elements which use B-spline basis functions to represent the displacement field. Application of this approach to design a few simple mechanisms is presented.
Generation of State Transition Models Using Simulations for Unmanned Sea Surface Vehicle Trajectory Planning
Authors: Thakur Atul , Svec Petr , Gupta Satyandra K.
Published: June 2012

Trajectory planning for unmanned sea surface vehicles (USSVs) in high sea-states is a challenging problem. Large and somewhat stochastic ocean forces can cause significant deviations in the motion of the USSV. Controllers are employed to reject disturbances and get back on the desired trajectory. However, the position uncertainty can be still high and needs to be accounted for during the trajectory planning to circumvent collisions with the obstacles. We model the motion of the USSV as Markov decision process and use a trajectory planning approach based on stochastic dynamic programming. A key component of our approach is the estimation of transition probabilities from one state to another when executing an action. In this paper, we present algorithms to generate state transition model using Monte Carlo simulation of USSV motion. Our simulations are based on potential flow based 6-DOF dynamics. Using this approach, we are able to generate dynamically feasible trajectories for USSVs that exhibit safe behaviors in high sea-states in the vicinity of static obstacles.
An Approach for Identifying Gaps and Overlaps in Standards to Determine Product Applicability
Authors: Witherell Paul , Sarkar Prabir , Narayanan Anantha , Lee Jae Hyun , Rachuri Sudarsan
Published: June 2012

Standards and regulations have become an important part of today’s society. Organizational and geographical dispersions often create situations where manufacturers are forced to meet various standards for a product to reach expanded markets or improve branding. In this paper we propose an approach that provides stakeholders with the means to harmonize a set of standards by identifying similarities and differences between their coverage. Using an analysis approach based on the Zachman framework, we are able to identify both overlaps and gaps that may transpire when analyzing multiple standards associated with a single product domain. To demonstrate our approach, we apply it to a subset of electronics-related sustainability standards. The results are sets of terms that can be used to define the gaps and overlaps between three standards: RoHS (Restriction of Hazardous Substances Directive), WEEE (Waste Electrical and Electronics Equipment Directive), and IEEE (Institute of Electrical and Electronics Engineers) P1680. We then discuss some of the challenges encountered when analyzing these standards. Finally, we briefly discuss the potential for an expanded approach that could assist in the development of domain models and ultimately help identify necessary actions in business processes that will lead to additional standard compliance.
An Information Modeling Methodology for Sustainability Standards
Authors: Narayanan Anantha , Lee Jae Hyun , Witherell Paul , Sarkar Prabir , Rachuri Sudarsan
Published: June 2012

Standards and regulations are developed and introduced in the market to meet the needs of specific domains. As standards are usually developed by experts within a particular domain, the modeling requirements necessary to represent the information associated with these standards are often not well understood. The lack of clear understanding of information requirements creates an environment where information models can become difficult to produce from standards, and the criteria for complying with these standards may be obscure. The variety of challenges encountered in codifying standards using information models necessitates a carefully devised methodology that takes all areas of the whole enterprise into consideration. This paper presents a methodology for the development of information models to complement and support standards based on the Zachman framework for enterprise architecture. In this paper, we will discuss some of the challenges encountered in modeling information for standards and regulations related to sustainability, and subsequently describe how our approach can be used to address these challenges. We will illustrate our approach by developing an example information model to support RoHS (Directive on the restriction of the use of certain hazardous substances in electrical and electronic equipment). This work could lead to the development of software tools and environments for computer aided standards development. Finally, we discuss the advantages and drawbacks of our methodology.
Evaluation of Communication Induced Checkpointing in Resource Constrained Embedded Systems
Authors: Sababha Belal H. , Rawashdeh Osamah A.
Published: June 2012

Reconfiguration-Based Fault-Tolerance is one approach for developing dependable safety-critical embedded applications. This approach, compared to traditional hardware and software redundancy, is a promising technique that may achieve the required dependability with a significant reduction in cost in terms of size, weight, price, and power consumption. Reconfiguration necessitates using proper checkpointing protocols to support state reservation and task migration. One of the most common approaches is to use Communication Induced Checkpointing (CIC) protocols, which are well developed and understood for large parallel and information systems, but not much has been done for resource limited embedded systems. This paper implements four common CIC protocols in a resource constrained distributed embedded system with a Controller Area Network (CAN) backbone. An example feedback control system implementation is used for a case study. The four implemented protocols are described and performances are contrasted. The paper compares the protocols in terms of network bandwidth consumptions, CPU usages, checkpointing times, and checkpoint sizes in additional to the traditional measures of forced to local checkpoint rations and total number of checkpoints.
Enhancing Experiential Learning in Collaborative-Competitive Student Design Teams
Authors: Hurdelbrink Keith , Doyle Bobby , Collins David , Evans Nic N. , Hatch Paul A. , Ingram Thomas , Kucinskas James W. , Moorhead-Rosenberg Zachary , Siddique Zahed
Published: June 2012

Engineering educators and practitioners have suggested that collaborative-competitive team design events promote innovation. These competitions are popular, and they attract sponsors and participants. Beyond being popular, they are believed to provide rich learning opportunities for students. In this paper we present a peer-to-peer learning environment for student centered learning to have a more appropriate mix of theory and experience (hands-on activities) to provide a complete experiential learning environment for collaborative-competitive student design teams. A student-taught seminar course on designing an FSAE vehicle is being offered to new members of the team to address issues in collaborative-competitive student design teams, which addresses the concrete experience and active experimentation element of the experiential model, but has deficiencies in the reflective observation and abstract conceptualization elements of the cycle. In this paper we will present the structure of the seminar course and how it tries to support and enhance the experiential learning in the FSAE team.
Nano-Scale Forces, Stresses, and Tip Geometry Evolution of Amplitude Modulation Atomic Force Microscopy Probes
Authors: Vahdat Vahid , Grierson David S. , Turner Kevin T. , Carpick Robert W.
Published: June 2012

Atomic-scale wear is one of the main factors that hinders the performance of probes for atomic force microscopy (AFM) [1–6], including for the widely-used amplitude modulation (AM-AFM) mode. To conduct consistent and quantitative AM-AFM wear experiments, we have developed a protocol that involves controlling the tip-sample interaction regime, calculating the maximum contact force and normal stress over the course of the wear test, and quantifying the wear volume using high-resolution transmission electron microscopy imaging (HR-TEM). The tip-sample interaction forces are estimated from a closed-form equation that uses the Derjaguin-Mu¨ller-Toporov interaction model (DMT) accompanied by a tip radius measurement algorithm known as blind tip reconstruction. The applicability of this new protocol is demonstrated experimentally by scanning silicon probes against ultrananocrystalline diamond (UNCD) samples. The wear process for the Si tip involved blunting of the tip due to tip fragmentation and plastic deformation. In addition, previous studies on the relative contributions of energy dissipation processes to AFM tip wear are reviewed, and initial steps are taken towards applying this concept to AM-AFM.
Understanding Rural Village Energy Needs and Design Constraints
Authors: Bryden Kenneth M. , Johnson Nathan G.
Published: June 2012

Today the primary challenge confronting engineers is to develop clean, sustainable technologies that can meet the needs of all of the world’s people. Traditionally this effort has focused on meeting the needs of the developed world. It is generally assumed that products needed for the developing world already exist or are relatively simple and hence do not require significant engineering design effort. As a consequence, many of the products intended to meet the needs of the poor miss the mark and do not meet their needs. This is particularly true in the design of products and processes intended to address the energy needs of the rural poor. Too often a set of standard assumptions is used, resulting in poor problem definition. And, because the design problem is not well defined, the resulting products and processes fail. Throughout the developing world it is common to find village water and energy projects that have failed. To design products and processes that meet the energy needs of the rural poor, the critical first step in the design process is a detailed in-village study of energy production and consumption dynamics. Quantifying village energy dynamics provides insight into the unfulfilled or unsatisfied needs of the consumer, establishes the design constraints, aids the engineer and the community members in prioritizing needs, and builds trust with the local community. This paper presents a field methodology developed to understand the energy needs of a rural sub-Saharan village of 700 people and discusses how this field methodology was used to establish the design constraints needed for a comprehensive energy solution.
Nonlinear Finite Element-Based Path Following of Periodic Solutions
Authors: Arena Andrea , Formica Giovanni , Lacarbonara Walter , Dankowicz Harry
Published: June 2012

A computational framework is proposed to path follow the periodic solutions of nonlinear spatially continuous systems and more general coupled multiphysics problems represented by systems of partial differential equations with time-dependent excitations. The set of PDEs is cast in first order differential form (in time) u˙ = f(u,s,t;c) where u(s,t) is the vector collecting all state variables including the velocities/time rates, s is a space coordinate (here, one-dimensional systems are considered without lack of generality for the space dependence) and t denotes time. The vector field f depends, in general, not only on the classical state variables (such as positions and velocities) but also on the space gradients of the leading unknowns. The space gradients are introduced as part of the state variables. This is justified by the mathematical and computational requirements on the continuity in space up to the proper differential order of the space gradients associated with the unknown position vector field. The path following procedure employs, for the computation of the periodic solutions, only the evaluation of the vector field f. This part of the path following procedure within the proposed combined scheme was formerly implemented by Dankowicz and coworkers in a MATLAB software package called COCO. The here proposed procedure seeks to discretize the space dependence of the variables using finite elements based on Lagrangian polynomials which leads to a discrete form of the vector field f. A concurrent bifurcation analysis is carried out by calculating the eigenvalues of the monodromy matrix. A hinged-hinged nonlinear beam subject to a primary-resonance harmonic transverse load or to a parametric-resonance horizontal end displacement is considered as a case study. Some primary-resonance frequency-response curves are calculated along with their stability to assess the convergence of the discretization scheme. The frequency-response curves are shown to be in close agreement with those calculated by direct integration of the PDEs through the FE software called COMSOL Multiphysics. Besides primary-resonance direct forcing conditions, also parametric forcing causing the principal parametric resonance of the lowest two bending modes is considered through construction of the associated transition curves. The proposed approach integrates algorithms from the finite element and bifurcation domains thus enabling an accurate and effective unfolding of the bifurcation and post-bifurcation scenarios of nonautonomous PDEs with the underlying structures.
The Role of Conceptualization and Design in Product Realization
Authors: El-Sayed Mohamed E. M.
Published: June 2012

The term Product realization is usually used to describe the physical realization of a product in the product development cycle. Therefore, the term may or may not include conceptualization and design phases. Considering that product realization means bringing a product to reality, it is important to study the concept of reality to understand the role of conceptualization, design, and manufacturing in product realization. In this paper, the concept of reality is expanded to include the perceptual and virtual realities as integral parts of the product realization process. This paper discusses the three phases of realization and their interactions. It also addresses the key roles of conceptualization, design and manufacturability in the realization process. To illustrate the concepts, presented in the paper, some examples are included.
Optimization-Based Seated Posture Prediction Considering Contact With Environment
Authors: Howard Brad , Yang Jingzhou James
Published: June 2012

People can spend much of everyday completing seated tasks. Therefore it is important to understand postures needed to complete seated tasks, and the associated environmental contacts. This paper presents a method to predict seated postures and the general forces needed in order to support resulting postural configurations. This study uses optimization techniques to predict human posture based on a 56 degree of freedom (DOF) 50th percentile female human model. The support reaction forces (SRFs) are predicted using joint torques and the zero-moment point (ZMP) formulation derived from the Lagrangian recursive dynamics. The SRFs are applied at points on the body based on center of pressure (COP) locations gathered from pressure mapping experiments. The specific application points include the two feet, the two thighs, and back. Multiple seated orientations based on an experimental study found in published literature are simulated. When comparing these simulation results to the literature data, a good correlation can be established, which provides an initial validation of the proposed methods.
Mobile Agent-Based Computing Resource and Usage Monitoring at Large Scale Computer Centers
Authors: Tie Zhixin , Ko David , Cheng Harry H.
Published: June 2012

Mobile agent technology has become an important approach for the design and development of distributed systems. However, there is little research regarding the monitoring of computer resources and usage at large scale distributed computer centers. This paper presents a mobile agent-based system called the Mobile Agent Based Computer Monitoring System (MABCMS) that supports the dynamic sending and executing of control command, dynamic data exchange, and dynamic deployment of mobile code in C/C++. Based on the Mobile-C library, agents can call low level functions in binary dynamic or static libraries, and thus can monitor computer resources and usage conveniently and efficiently. Two experimental applications have been designed using the MABCMS. The experiments were conducted in a university computer center with hundreds of computer workstations and 15 server machines. The first experiment uses the MABCMS to detect improper usage of the computer workstations, such as playing computer games. The second experimental application uses the MABCMS to detect system resources such as available hard disk space. The experiments show that the mobile agent based monitoring system is an effective method for detecting and interacting with students playing computer games and a practical way to monitor computer resources in large scale distributed computer centers.
A Real Options-Based Approach to Designing for Changing User Populations of Long-Lifetime Products
Authors: Nadadur Gopal , Garneau Christopher , de Vries Charlotte , Parkinson Matthew B.
Published: June 2012

In addition to robustness-related considerations, designers of long-lifetime products (e.g., buses, trains, freight trucks, and commercial aircraft) must also account for possible secular and demographic trends and their impacts on the ranges of anthropometry, capability, and preference of user populations. However, the uncertainty associated with forecasts of these trends complicates the decision-making process of the designer: One of the decisions to be made is whether to efficiently allocate adjustability to accommodate the required percentage of only the current user population or to allocate additional amounts of adjustability to allow for more uniformly high accommodation levels throughout the product’s lifetime. Postponing this decision until later in the life of the product could be a valuable option. This paper proposes a Black Scholes model-based real options methodology for the valuation of such decision-postponement in the design process. A simplified truck cab designed in 1977 and with a lifetime of 30 years is used as a demonstrative case study. The three population change scenarios considered are: no change, changes due to a secular trend (gradually increasing obesity), and changes due to a demographic trend (gradually changing gender split). Estimates of the body dimensions (anthropometry) of user populations in these three scenarios are utilized to study the impact of certain adjustability-allocation decisions on the accommodation levels of these populations. The secular trends scenario indicates the need to embed greater-than-optimal truck cab space which, in the future, may be used for a seat designed for the more obese user population. This decision is treated as a real option and is evaluated for different levels of uncertainty associated with secular trend forecasts and for different required rates of return. Despite the limitations of the approach due to certain simplifying assumptions, it is shown to be a good basis for future research into designing for changing user populations of long-lifetime products.
Ultra Low Power Energy Storage Circuit for Piezoelectric Nanogenerators
Authors: Galos Richard , Chen Xi , Shi Yong
Published: June 2012

MEMS and NEMs devices benefit many applications due to their unique performance and tiny size. We have researched replacing components of a Wireless Sensor Network (WSN) mote with several such devices. In this paper, we present an energy conversion and storage circuit that can be used with piezoelectric nanogenerators for self powered motes. Energy from external vibration or environmental acoustics is capacitively stored and released at certain time intervals according to the application. Stored and lost power is compared against a detailed WSN mote power budget to size the generator and capacitor.
Cracked Shaft Damage Identification via Symmetry Breaking Active Magnetic Bearing Control and Interrogation
Authors: Zhao J. , DeSmidt H. A.
Published: June 2012

A new vibration-based damage identification methodology for cracked rotor systems with periodically time-varying dynamics is developed and demonstrated on a shaft-disk system. This approach is based Floquet theory and utilizes measured changes in the system natural frequencies to estimate the severity and location of shaft structural cracks during operation. The damage identification is enhanced through the use of an Active Magnetic Bearing with adjustable support stiffness and acceleration feedback. Here, a novel symmetry-breaking closed-loop control is employed during the iterative damage identification process to enrich the data set by removing the Eigen degeneracy of the symmetric shaft structure. This approach enables full damage identification from a single sensor and hence without requiring measured modeshape information. The dynamical model of system is built based on the Lagrange principle and the assumed mode method while the crack model is based on fracture mechanics. The method is synthesized via harmonic balance and numerical examples for a shaft/disk system demonstrate the effectiveness in detecting both location and severity of the structural damage.
Exploring Marketing to Engineering Information Mapping in Mass Customization: A Presentation of Ideas, Challenges and Resulting Questions
Authors: Ferguson Scott , Olewnik Andrew , Cormier Phil
Published: June 2012

The paradigm of mass customization strives to minimize the tradeoffs between an ‘ideal’ product and products that are currently available. However, the lack of information relation mechanisms that connect the domains of marketing, engineering, and distribution have caused significant challenges when designing products for mass customization. For example, the bridge connecting the marketing and engineering domains is complicated by the lack of proven tools and methodologies that allow customer needs and preferences to be understood at a level discrete enough to support true mass customization. Discrete choice models have recently gained significant attention in engineering design literature as a way of expressing customer preferences. This paper explores how information from choice-based conjoint surveys might be used to assist the development of a mass customizable MP3 player, starting from 140 student surveys. The authors investigate the challenges of fielding discrete choice surveys for the purpose of mass customization, and explore how hierarchical Bayes mixed logit and latent class multinomial logit models might be used to understand the market for customizable attributes. The potential of using discrete choice models as a foundation for mathematically formulating mass customization problems is evaluated through an investigation of strengths and limitations.
Granularity Enhancement of Extracted Preferential Probabilities From Design Team Discussion
Authors: Ji Haifeng , Honda Tomonori , Yang Maria C.
Published: June 2012

Preferences are a formal way to represent a designer’s choices when assigning priorities for a set of possible design alternatives within the context of the design process. A design team’s preferences can change over the life of project, and knowledge of this evolution can be useful for understanding a team’s rationale as well as its confidence in a decision. This paper presents a “sliding window” approach (SPPT) to the extraction of preference related information from transcribed design team discussion. The approach suggested in this paper can assess design preferences over time with a finer granularity than a previous approach known as PPT, and removes perturbations that occur when there is little design team discussion. Both SPPT and PPT were applied to a discussion transcript. Results show good consistency among SPPT, PPT and survey results. SPPT is also able to detect more changes in design team preference.
Flow Induced Vibration and Critical Velocities
Authors: Ojetola Akindeji , Jameson Noel Jordan , Hamidzadeh Hamid R.
Published: June 2012

Flow induced instability has been observed in numerous fields, including the aerospace industry, nuclear reactor components and power generation/transmission. This paper considers the stability analysis of a cantilever pipe excited by the flow of fluid. The developed mathematical model can be used to determine a number of critical flow velocities where the instability may occur. The pipe is modeled as an Euler-Bernoulli beam by considering the effect of fluid mass and the Coriolis acceleration caused by the flow. The required mathematical procedure is presented and it is accompanied by a set of design guidelines for determining the stable and unstable condition for these structures. Parameters to be considered are velocity of the flow, density of the flow, and properties of the pipe as well as its geometry.
Terramechanics Modeling of Mars Surface Exploration Rovers for Simulation and Parameter Estimation
Authors: Iagnemma Karl , Senatore Carmine , Trease Brian , Arvidson Raymond , Bennett Keith , Shaw Amy , Zhou Feng , Van Dyke Lauren , Lindemann Randel
Published: June 2012

In 1997 and 2004, small wheeled robots (“rovers”) landed on the surface of Mars to conduct scientific experiments focused on understanding the planet’s climate history, surface geology, and potential for past or present life. Recently, the Mars Exploration Rover (MER) “Spirit” became deeply embedded in regolith at a site called Troy, ending its mission as a mobile science platform. The difficulty faced in navigating mobile robots over sloped, rocky, and deformable terrain has highlighted the importance of developing accurate simulation tools for use in a predictive mobility modeling capacity. These simulation tools require accurate knowledge of terrain model parameters. This paper describes a terramechanics-based tool for simulation of rover mobility. It also describes ongoing work toward estimation of terrain parameters of Mars soil.
Comparison of Life Cycle Assessment of Two Toasters
Authors: Srinivasan Raghunathan , Ameta Gaurav
Published: June 2012

The objective of this paper is to determine and compare the environmental impacts of two toasters: standard and eco-friendly. The most rapidly growing sector for the e-waste world comes from Electronic household products. More than 2 million tons of electronic products are disposed off as solid waste to landfills in the US alone. The demand for energy supplies has been rapidly increasing in the past decade. Strict legislative measures should be enforced to protect the environment by making industries collect back the manufactured products at the End-of-Life (EOL) from the users and recycle the products. If these necessary steps are not taken, then these e-wastes will impose serious threat to society and the environment. In order to re-design environmentally friendly products and facilitate sustainable take-back planning, current products need to be evaluated for their environmental impacts. One of the widely used methodologies to assess the environmental impacts of a product is called Life Cycle Assessment (LCA). LCA is a cradle to grave approach for assessing the environmental impacts of a product. The cradle to grave approach includes raw material phase, manufacturing and assembly phase, use phase, recovery phase and disposal phase. The system boundary for LCA presented in this paper includes material phase, manufacturing phase, use-phase and disposal phase. The functional unit for the LCA is entire life of the toaster which is one year based on manufacturer’s warranty which also includes the rate of usage. The environmental impacts from the two toasters as presented in this paper include eutrophication, acidification, energy-use and global warming. The use phase energy impact is experimentally determined.
Identification of Blockage in a Pipe Using Modal Analysis
Authors: Bello Oladapo , Virani Nishant , Oyadiji S. Olutunde
Published: June 2012

The use of acoustic finite element modal analysis for simulating and identifying blockage in a pipe network is presented in this paper. The analysis commences with a straight fluid-filled pipe without any flaw. The natural frequencies of the acoustic modes of the fluid in the pipe are computed. Blockages of different magnitudes are introduced at different locations along the length of the pipe. The corresponding natural frequencies of the acoustic modes of the fluid in the pipe are again computed by finite element technique. From these results, the modal characteristics of partially blocked pipes are established and compared with simulation results of defect-free fluid-filled pipes in order to ascertain the defect location and sizes.
Enhanced Design of Vibration Energy Harvester Using Dual Masses
Authors: Tang Xiudong , Zuo Lei
Published: June 2012

A type of dual-mass vibration energy harvester, where two masses are connected in series with the energy transducer and spring, is proposed and analyzed in this paper. The dual-mass vibration energy harvester is proved to be able to harvest more energy than the traditional single degree-of-freedom (DOF) one when subjected to harmonic force or base displacement excitation. The optimal parameters for maximizing the power output in both the traditional and the new configurations are discussed with taking the parasitic mechanical damping of the system into account. In consistent of the previous literature, we find that the optimal condition for maximum power output of the single DOF vibration energy harvester is when the excitation frequency equals to the natural frequency of the mechanical system and the electrical damping due to the energy harvesting circuit is the same as the mechanical damping. However, the optimal conditions are quite different for the dual-mass vibration energy harvester. It is found that two local optimums exist, where the optimal excitation frequency and electrical damping are analytically obtained. The local maximum power of the dual-mass vibration energy harvester is larger than the global maximum power of single DOF one. Moreover, at certain frequency range between the two natural frequencies of the dual-mass system, the harvesting power always increases with the electrical damping ratio. This suggests that we can obtain higher energy harvesting rate using dual-mass harvester. The sensitivity of the power to parameters, such as mass ratio and tuning ratio, is also investigated.
Conditions of Equivalence Between Continuum and Discrete Sensitivities
Authors: Kim Nam Ho
Published: June 2012

The purpose of this paper is to show equivalence between continuum and discrete formulations in sensitivity analysis when a linear velocity field is used. Shape sensitivity formulations are presented when the body forces and surface tractions depend on shape design variables. Especially, the continuum-discrete (C-D) and discrete-discrete (D-D) approaches are compared in detail. It is shown that the two methods are theoretically and numerically equivalent when the same discretization, numerical integration, and linear design velocity fields are used. The accuracy of sensitivity calculation is demonstrated using a cantilevered beam under uniform pressure and an arch dam crown cantilever under gravity and hydrostatic loading at the upstream face of the structure. It is shown that the sensitivity results are consistent with finite difference results, but different from the analytical sensitivity due to discretization and approximation errors of numerical analysis.
Reverse Engineering System Based on Uniforming Measurement Data in 3D-Lattice
Authors: Shibata Gaku , Aoyama Hideki , Sato Megumi
Published: June 2012

This paper deals with four processes for constructing mathematical models based on measurement data. The first process is smoothing measurement data based on the hypothesis that a small area of a curved surface can be approximated to an ellipsoid. The second process is fitting the measurement data into the cross points between a 3D lattice and filling points by approximating the ellipse surface. As information on the positions of data is converted from coordinate value into integral code, it is easier to find neighboring points and clear neighboring relations between surfaces help prevent the gap between neighboring surfaces when constructing the surfaces. The third process is recognizing surfaces and boundary lines composing a physical model from the curvature of the points located on the 3D lattice and variance of the coordinate values of the points. The last process is approximately defining NURBS surfaces by the minimum square method to average positional errors. Experiments on surface construction were conducted to show the usefulness of the proposed methods.
Challenges in Development of Sub-Millimeter Resolution Thermo-Fluidic Actuator Based Wearable Tactile Display System for Blind Individuals
Authors: Naidu Prakash C. R. J. , Yechangunja Ramesh , Prosperetti Andrea , Srinivasan Mandayam A.
Published: June 2012

This paper presents the work conducted towards the realization of a novel tactile display system composed of miniature thermo-fluidic actuators. An application of the system particularly relevant to blind individuals is communication with computers through touch. The development of programmable spatio-temporal pattern of touch actuation based on bubble formation and vapor pressure has remarkable scope, not only because of the flexibility and wearability but also the high levels of motion amplitude and force of actuation not achieved so far by other means. The design specifications of the tactile display involved packaging of the miniature actuators in such a manner that the display can be conveniently attached at the tip of the human finger with desirable spatial resolution, and achieving the optimum force that can be felt through the human finger. However, there were challenges that were faced by the authors while miniaturizing the actuators for suitability in sub-millimeter spatial resolution desirable for the tactile display. The paper reports on the design, prototype development and experimental results and brings out the limitations along with possible solutions being pursued by the authors. The progressive efforts through fabrication and testing of different prototype thermo-fluidic actuators ranging from 3mm diameter bore to sub-millimeter sizes and the corresponding difficulties faced in the form of cooling requirements, hysteresis effects, and fabrication challenges are elucidated. The paper reports on packaging of actuators as an array of tiny tubes spaced as close as possible, and establishment of parameters, namely, amplitude of actuation and switching frequency, along with force generation adequate for tactile perception.