bluuebunny/crossref_metadata_2025 huggingface dataset:
Nonlinear Dynamical Interaction Between Insonified Microbubbles
Authors: Tsuruoka Akira , Kubo Hiroki , Sugiura Toshihiko
Published: September 2013

Microbubbles are expected to be applied for ultrasonic therapy. In this research, considering two neighboring bubbles, we added to the Rayleigh-Plesset equation the term of nonlinear influence corresponding to pressure change caused by the neighboring bubble’s oscillation, and numerical simulation was performed.

It is known that the natural frequency of a microbubble decreases with increasing the bubbles’ density. This fact agrees with our analytical prediction based on the Rayleigh-Plesset equation. Further, the natural frequency also depends on the diameter ratio of the two bubbles. Our numerical results show that superharmonic response reaches a peak at some distance between bubbles when they are driven at half their resonance frequency with their ratio of the natural frequency being two to one. Numerical simulation also shows that if the two bubbles of the same size exist at a close distance, the occurrence region of the subharmonics is larger than that of a single bubble.
Image-Based Remote Real-Time Volume Rendering: Decoupling Rendering From View Point Updates
Authors: Zellmann Stefan , Aumüller Martin , Lang Ulrich
Published: September 2013

Remote rendering is employed when the visualization task is too challenging for the hardware used to display a dataset or when it is too time consuming to transfer the complete dataset. Volume visualization with its dataset sizes growing with the 3rd power of their spatial resolution is such a task. Since remote rendering introduces additional sources of latency, its applicability to virtual environments is limited because of the required low delays from user action to displayed image. We counter these latencies with image-based rendering techniques: color image data along with additional depth information is warped, while new data has not been completely received. Using these approximate images, it is possible to decouple the cheap display phase from rendering. While depth values are trivially deduced for polygons, we contribute heuristics for volumetric datasets with varying transparency.
Parallel CAE System for Large Scale Problems Based on HTML5 and WebGL
Authors: Yodo Kaworu , Shioya Ryuji , Miyoshi Akio , Asaumi Takuru
Published: September 2013

We have developed a prototype of web based CAE system with HTML5 and WebGL technology and the ADVENTURE system. The main system including solver part is operated on the remote server like a cloud computing and user interface client is operated in a web browser on the Internet devices (including PCs, smartphones, and tablet devices) without any additional software or plug-ins.

In this system, we use the ADVENTURE system as server-side CAE system. The ADVENTURE system is a general-purpose computational analysis system we have been developing. Aim of the system is to enable to analyze a three dimensional finite element model of arbitrary shape over 100 million Degrees Of Freedom (DOF) mesh on massive parallel computers like a large-scale PC cluster or a super computer. To solve large scale problem, domain-decomposition-based parallel algorithms are implemented in pre-processes (domain decomposition), main processes (system matrix assembling and solutions) and post-process (visualization) of the ADVENTURE system, respectively. The hierarchical domain decomposition method (HDDM) with the balancing domain decomposition (BDD) as a pre-conditioned iterative solver is adopted in the main processes. Module-based architecture of the system with standardized I/O format and libraries are also developed and employed to attain flexibility, portability, extensibility and maintainability of the whole system.

Since the software has become a quite large system, it is not easy to install or operate the system on parallel machines by users. To solve this issue, the authors have been developed CAE system for large scale problems based on computer network. With this system, the main system including solver part is operated on the remote server like a cloud computing and to operate such a system from a client PC through the network. Users need not to touch server system and easy operation on client system was developed. But this system requires for users to install client software, which may become a barrier to start using the system.
Dynamic Features of Gear System With Tooth Crack and Tooth Surface Sliding due to Speed Variation
Authors: Wang Liming , Chen Zaigang , Shao Yimin , Wang Xi
Published: September 2013

It was found that the vibration features resulted from tooth crack and sliding on the contact interfaces due to speed variation are very similar with each other, which is difficult to distinguish. So, it is meaningful to study whether they are the same or not. Firstly, a finite element model of a spur gear pair in mesh with tooth crack at pitch circle is established to calculate the effect of tooth crack on gear mesh stiffness. Then, combined with the tooth crack through mesh stiffness, a spur gear dynamic model with six degrees of freedom (dof) is developed to extract the dynamic features affected by the tooth crack. The tooth surface friction due to different relative velocity is also involved to study its effects on the dynamic characteristics of the gear system. Finally, comparisons are made between the dynamic features of the gear system with tooth crack and the tooth surface sliding to expose their effects to supply some theoretical guidance on fault detection.
Navigating the Uncharted Waters: An Emotional Engineering Approach to Decision Making
Authors: Fukuda Shuichi
Published: September 2013

Although there are many approaches to decision making, most of them are tools for the Closed World, and you can make decisions before you sail out. But the world we are living in now is an Open World, where there is no chart. We have to make decisions while we are navigating. Economists, Simon and Keynes, say that in a Closed World economic agents make decisions rationally, but in an Open World they rely on emotion.

This paper describes that by introducing directed graph and declarative programming techniques, we can simulate emotion-driven decision making. This approach has several advantages. One important one is we can introduce emotion into quality function deployment. Quality is not just function requirements. Quality is nothing other than customers’ expectations. And emotions are closely related to their expectations and satisfactions. Another advantage is that as engineering needs more and more diverse pieces of knowledge, it is becoming increasingly difficult to see the whole picture. But this approach permits decision making in your own way and still meeting customers’ expectations adequately.
A Polynomial Approach to Inverse Kinematics of Rolling Contact
Authors: Cui Lei , Dai Jian S.
Published: September 2013

A moving object has three rotational degrees of freedom with respect to the fixed one when the two objects maintain rolling contact. Thus three kinematic inputs are considered necessary for the moving object to follow a trajectory described by its velocity profile as function of time. This paper formulates the problem as a system of three nonlinear equations and reduces it to solving a polynomial of degree six with one variable. This leads to fast and accurate numerical approximations of roots on a computer either by commercial software or open-source software. This polynomial formulation is different from previous ones that require solving a system of nonlinear ordinary differential equations.
Structuring Requirements in a Multi-Project Environment in the Construction Industry: A Life Cycle Perspective
Authors: Wörösch Michael
Published: September 2013

Being in control of requirements in building projects is vital, since it helps securing the often small profit margins and the reputation of the responsible company. Hence this research aims to introduce requirements management to the construction industry. By means of case study and action research conducted at a Danish construction syndicate producing sandwich elements made from High Performance Concrete and insulation materials it is demonstrated that requirements management successfully can be used in construction. Since requirements management as of today has not found its use in this industry, yet, success is here defined as an accomplished and accepted implementation of requirements management processes that are used by the relevant project members in their daily work and where the benefits of implementing requirements management outweighs the cost of invested resources. Furthermore it is argued that when running technology development, product development, product platform development, and a portfolio of building projects at the same time the use of requirements management is advantageous and an intelligent way of structuring requirements is needed. This article also demonstrates that the application of requirements management with gain can be extended to cover entire life cycles as e.g. the life cycle of a building. This is done by proposing a requirements structure that attempts to consider future events. The proposed structure is divided into the areas: company, technology, product platform, and building and covers all encountered types of requirements, e.g. functional (defines what a system is supposed to do), non-functional (defines how a system is supposed to be), technical, organizational, and even personal requirements. As a result the conducted research clearly shows that requirements management can be applied to the construction industry. At the same time it also becomes obvious that it is necessary to open doors to further research looking into not only using requirements databases & processes especially designed for the construction industry but also the training of key personnel in requirements management, and how the introduction of requirements management can impact the construction industry and their customers in the long run.
Design Method Selection Matrix for Facilitating Product Platform and Family Design
Authors: Nomaguchi Yutaka , Askhøj Anders , Madsen Kristian F. , Akai Ryota , Fujita Kikuo
Published: September 2013

The aim of this research is to develop a method to manage product platform and family design methods and to select one appropriate for a specific design case. As the need for product platform has increased over the last 20 years, research within the area has led to the development of various methods that aim at evaluating a candidate of design. While sharing similar approach, different researchers have developed different methods that vary greatly in type, focus and complexity. Although their differences are considered a strong point of the theoretical field, the large variety can end up complicating the selection process, which will result in choosing less optimal methods for a specific design case. This paper proposes Design Method Selection Matrix (DMSM) that can help designers choose appropriate design methods. The underlying basis for the proposed DMSM is to determine methods appropriateness based on the availability of information, which is defined by the situation in which the evaluation takes place, as well as the importance of information, which is determined by the goal of the evaluation. The output of DMSM is a score for each of the identified methods that represent the appropriateness of the given method, based on the situation and goal(s) chosen by the designer. Suggestions are based on parameters that can easily be determined by designers without extensive experience within platform based product design. The case study demonstrates the effectiveness of DMSM.
Dissipative Energy Flow in Systems at Parametric Anti-Resonance
Authors: Dohnal F.
Published: September 2013

Recent investigations have shown theoretically and experimentally that the transient vibrations of a lightly damped system can be suppressed or even stabilized by a time-periodic open-loop control of one of its system parameters. Introducing time-periodicity in system parameters may lead, in general, to a dangerous and well-known parametric resonance. In contrast to such a resonance, a properly tuned time-periodicity is capable to extract vibration energy from the system and to increase the effective damping of transient vibrations. At this specific operation the system is tuned at parametric anti-resonance.

The beneficial interaction of damping and time-periodicity was first formulated by A. Tondl in 1998. His pioneering work deals with stabilizing self-excited vibrations. It was proven by F. Dohnal in 2005 that the vibrations of a general lightly damped system (not necessarily unstable) can be reduced by parametric anti-resonance, too. A physical interpretation of the parametric anti-resonance is related to the coupling of vibration modes of the underlying system with constant coefficients. This interpretation leads intuitively to the calculation of the energy flow of each vibration mode and leads to clear physical insight of how parametric anti-resonances work. This interpretation of mode coupling is developed further resulting in an approximate analytical expression for the effective damping of a system driven at parametric anti-resonance. This expression allows the statement of the maximum effective damping achievable by this method. The discussion of the energy flow of a linear, lightly damped system possessing a time-periodic stiffness coefficient its physical and modal displacements highlights the coupling of vibration modes of the underlying system with constant coefficients.
Geometric Interpretation and Optimization of Large Semantic Data Sets in Real-Time VR Applications
Authors: Hempe Nico , Rossmann Jürgen , Waspe Ralf
Published: September 2013

Current real-time VR applications are based on well-defined digital representations of the environment. In order to render a realistic looking environment with good performance, artists and developers with specific expertise are indispensable to create optimized data. However modern applications, especially those incorporating data from geo information (GIS) or product data management (PDM) systems, need to be able to use unrefined data without offline conversion or loss of render performance. In this paper we present an extensible object oriented graph database, which further embraces the paradigm of object orientation by incorporating the simulation functionality into the database itself. Whole scene descriptions including all functionalities can be described by one single database. Optimization techniques will be introduced, which are automatically applied to the simulation data, in order to extract a render-friendly structure. Specific semantic objects can be interpreted by the render framework to enhance the simulation, in both function and visual representation.
Applications of 3D Level Set Topology Optimization
Authors: Brampton Christopher J. , Kim Hyunsun A. , Cunningham James L.
Published: September 2013

Level set topology optimization defines the solution using the level set function values stored at the nodes of a regular finite element grid. These values represent a signed distance function which indicates the distance from each node to the structural boundaries. During optimization, nodal sensitivities are used to update the level set function values, moving the boundaries to create a more optimal structure. This paper presents two applications of the 3D level set topology optimization procedure aiming to minimize structural compliance subject to a volume constraint. The first application is the internal structure of a light subsonic aircraft wing. The results suggest that an alternative arrangement of ribs and sparse may be a more optimal solution for wing structures. The second application is the internal trabecular bone structure of an os-calcis. Comparison of the modeled optimal structure and the real internal structure suggest the internal bone structure is mechanically optimal.
A Dental Matching Approach Using Partial Surface Features for Human Identification
Authors: Zhong Xin , Wong Yoke San , Lu Wen Feng , Foong Kelvin W. C. , Cheng Alan Ho-lun
Published: September 2013

A novel 3D dental identification framework is presented. The objective is to develop a methodology to enable computer-automated matching of complex dental surfaces with possible missing regions for human identification. Thus far, there is no reported attempt at 3D dental identification given partially available dental casts or impressions. This approach overcomes a number of key hurdles in traditional 2D methods. Given the 3D digital form of a dental cast surface, the developed method will facilitate the search for the closest match in the database of digitized dental casts. A salient curvature matching algorithm (SCM) is proposed for pose estimation which includes algorithms for feature extraction, feature description and correspondence. The feature point extraction algorithm could extract more salient features and the correspondence algorithm is more robust for pose estimation compared to known works. Experimental results show 85.7% hit rate at rank-1 accuracy based on matching of 7 partial sets to a database of 100 full sets in significantly reduced retrieval time. The hit rate increases to 100% with parameter adjustment. This work aims to enable computer-aided 3D dental identification and the proposed method could be adjunctively used with the traditional 2D dental identification method, as the available dental source for identification is still primarily 2D radiographs. Limitations of the methodology and future directions in matching highly fragmented and partial dental surfaces are discussed.
Overcoming Stopovers in Cycloidal Rotor Propulsion Integration on Air Vehicles
Authors: Páscoa José C. , Ilieva Galina I.
Published: September 2013

A cyclorotor (also known as a cyclocopter or cyclogiro) is a rotating-wing system where the span of the blades runs parallel to the axis of its rotation. The pitch angle of each of the blades is varied cyclically by mechanical means such that the blades experiences positive angles of attack at both the top and bottom positions of the azimuth cycle. The resulting time-varying lift and drag forces produced by each blade can be resolved into the vertical and horizontal directions. Varying the amplitude and phase of the cyclic blade pitch can be used to change the magnitude and direction of the net thrust vector produced by the cyclorotor. Compared to a conventional rotor, each spanwise blade element of a cyclorotor operates at similar aerodynamic conditions (i.e., at similar flow velocities, Reynolds numbers, and angles of incidence), and so the blades can be optimized to achieve the best aerodynamic efficiency. Moreover, because the blades are cyclically pitched once per revolution (1/rev), unsteady flow mechanisms may delay blade stall onset and in turn may augment the lift produced by the blades. Albeit proposed to MAV-scale, its use on large scale vehicles turns problematic, and we proposed in this paper to address their stopovers. Furthermore, since the thrust vector of a cyclorotor can be instantaneously set to any direction perpendicular to the rotational axis, a cyclorotor-based air vehicle may ultimately show better maneuverability and agility as compared to a classical powered conventional rotor system. One major drawback of a cyclorotor is its relatively large rotating structure which might offer a weight penalty when compared to a conventional rotor.
A Method for the Optimal Design of Automotive Rubber Components
Authors: Gobbi Massimiliano , Previati Giorgio , Mastinu Gianpiero
Published: September 2013

The paper presents a method for the design of rubber components for automotive applications.

The design of a rubber component is complex due to the dependence of its behavior not only on the geometry but also on the non-linear, frequency dependent characteristics of the material. A finite element (FE) model able to estimate stiffness, stress and filtering characteristics of the component is presented. The rubber is modeled by a non-linear model whose parameters are estimated from experimental tests. The dynamic behavior is described by means of storage and dissipation moduli given as function of the excitation frequency.

The design of the component, which is a bushing to be fitted on a front double wishbone suspension, is accomplished by changing the main geometrical parameters while choosing between three different rubber types. Geometrical and material parameters are varied inside the FE model by an automatic procedure. The optimal set is derived by means of a multi-objective genetic algorithm.

The proposed procedure allows to define the geometric dimensions of the component along with the most suitable material among a given set.
Comparison of Problem Solving From Engineering Design to Software Design
Authors: Ahmed-Kristensen Saeema , Babar Muhammad Ali
Published: September 2013

Observational studies of engineering design activities can inform the research community on the problem solving models that are employed by professional engineers. Design is defined as an ill-defined problem which includes both engineering design and software design, hence understanding problem solving models from other design domains is of interest to the engineering design community. For this paper an observational study of two software design sessions performed for the workshop on “Studying professional Software Design” is compared to analysis from engineering design. These findings provide useful insights of how software designers move from a problem domain to a solution domain and the commonalities between software designers’ and engineering designers’ design activities. The software designers were found to move quickly to a detailed design phase, employ co-evolution and adopt a predominantly depth-first approach to developing their solutions. A mapping between the activities of engineering design onto the activities of a general model of software design is also presented. A discussion about the potential consequences of the key findings across the design domains is described.
A Springback Compensation System Based on Springback Mechanics and Design Parameter Optimization
Authors: Doke Naoyuki , Oya Tetsuo
Published: September 2013

A new springback compensation system based on springback mechanics is developed. The cause of springback is the bending moment before springback. To compensate the tool shape, it is necessary to satisfy the springback mechanical equation which is expressed by curvature and bending moment. In this system, the bending moment before springback is designed considering the springback mechanical equation. Actually, the optimum bending moment distribution is designed by modifying the design parameters such as curvature and punch load in this system so that the metal sheet is deformed into the desired shape. In the modification process of the design parameters such as curvature and punch load, the sequential response surface method is used to optimize them. When the proposed method was applied to V-bending, it was found that it was effective because the convergence rate is great and not only the curvature but also the punch load can be obtained.
Categorizing Affordances for Product Design
Authors: Hu Jun , Fadel George M.
Published: September 2013

To compensate for the inability of the functional descriptions to describe for instance interactions between users and artifacts, the term affordance has been introduced in design methodology by Maier and Fadel. However, some significant details of affordance such as representation, categorization, and application to mechanical design still need to be further studied. Therefore, this paper reviews and compares the use of the term affordance in the fields of Human-Computer Interaction (HCI), Artificial Intelligence (AI), design, psychology, and philosophy. Based on that review, a new categorization scheme of affordances applicable for product design is proposed. The categories including doing and happening Artifact-Artifact Affordances (dAAA and hAAA), doing and happening Artifact-Environment Affordances (dAEA and hAEA), and doing and happening Artifact-User Affordances (dAUA and hAUA) are identified and an initial statistical evaluation is performed to support this proposal. The detailed description of these affordances provides better coverage, more orthogonality, more depth, and could be more usable, eventually meeting the requirements of a taxonomy.
Critical Speeds, Divergence, and Flutter Instability in High-Speed Planetary Gears
Authors: Cooley Christopher G. , Parker Robert G.
Published: September 2013

The structured properties of the critical speeds and associated critical speed eigenvectors of high-speed planetary gears are given. Planetary gears have only planet, rotational, and translational mode critical speeds. Divergence instability is possible at speeds adjacent to critical speeds. Numerical results verify the critical speed locations. Divergence and flutter instabilities are investigated numerically for each mode type.
Build Time and Cost Models for Additive Manufacturing Process Selection
Authors: Yim Sungshik , Rosen David
Published: September 2013

Due to the varieties of available Additive Manufacturing (AM) technologies, it is challenging to select appropriate processes to cost effectively build a part, especially when a user does not have in-depth knowledge about AM. In this paper, we introduce approximate models of build time and cost for AM processes that can be used for early stage process selection. Therefore, a user can identify and compare candidate manufacturing processes based on build time and cost estimates that are computed from approximate geometric information about the part, specifically the part’s bounding box and its estimated volume. The build time model is based on a generalized parameterization of AM processes that applies to laser-based scanning (Stereolithography, powder bed fusion), filament extrusion (fused-deposition modeling), ink-jet printing, and mask-projection processes. Build time estimates were tested by comparing them to the measured build time of parts in fabricated using Stereolithography, ink-jet printing, and fused deposition modeling processes.
Bifurcations in Twinkling Oscillators
Authors: Panigrahi Smruti R. , Feeny Brian F. , Diaz Alejandro R.
Published: September 2013

We present the underlying dynamics of snap-through structures that exhibit twinkling. Twinkling occurs when the nonlinear structure is loaded slowly and the masses snap-through, converting the low frequency input to high frequency oscillations. We have studied a nonlinear spring-mass chain loaded by a quasistatic pull. The spring forces are assumed to be cubic with intervals of negative stiffness. Depending on the parameters, the system has equilibria at multiple energy levels. The normal form and the bifurcation behaviors for the single and two degree of freedom systems are studied in detail. A new type of bifurcation, which we refer to as a star bifurcation, has been observed for the symmetric two degree of freedom system, which is of codimension four for the undamped case, and codimension three or two for the damped case, depending on the form of the damping.
Classification of Flapping Wing Mechanisms for Micro Air Vehicles
Authors: Ryan Mark , Su Hai-Jun
Published: September 2013

The purpose of this paper is to categorize the current state of technology in flapping wing mechanisms of micro air vehicles (MAVs). One of the major components of MAVs is the flapping mechanism, which actuates wings to generate sufficient lift and propulsion force. The goal of the flapping wing mechanism design is to develop a highly efficient and highly robust mechanism, which converts the input motion, either rotational or translational, to a beating motion at a frequency ranging from several to hundreds of Hz. The current practice of designing flapping mechanisms follows an ad-hoc approach with multiple design, build, and test cycles. This design process is very inefficient, costly, time-consuming, and not applicable to mass production of MAVs. This work will be an important step towards a systematic approach for the design of flapping mechanisms for MAVs. In this paper, we will study 15 flapping mechanisms used in recent MAV projects worldwide. We classify these mechanisms based on workspace, compliant or rigid body, type synthesis, mobility, and actuator type. This survey of mechanism classification will serve as a resource for the continued design and development of smaller and more efficient MAVs.
The Modal Decomposition in the Frequency Domain
Authors: Liang Yang , Feeny Brian
Published: September 2013

A frequency domain decomposition method is formulated to extract modal information of multi-degree-of-freedom systems. Previously, state-variable modal decomposition (SVMD), smooth orthogonal decomposition (SOD), and also proper orthogonal decomposition (POD), have used time domain signals for modal decomposition. Analysis shows that similar formulas can be obtained in the frequency domain, with eigenvalues as the resonance frequencies, and the eigenvectors as the inverse of the linear normal modes (LNMs). The method can be expressed in symmetric or non-symmetric eigenvalue problem format. The symmetric format resembles SOD in the frequency domain, while the non-symmetric method is similar to SVMD. One of the advantages of a frequency-domain method is that signals can be divided into frequency segments to find out the existence of natural frequencies and normal modes within a limited frequency range, such that the noise influence can be reduced. Furthermore, the obtained eigenvectors can be used to check if they actually are normal modes or noises. The method was examined by a six degree-of-freedom mass-spring system under free vibration and random excitation conditions.
Promoting and Managing End-of-Life Closed-Loop Scenarios of Products Using a Design for Disassembly Evaluation Tool
Authors: Favi Claudio , Germani Michele , Mandolini Marco , Marconi Marco
Published: September 2013

In recent years, environmentally conscious design has become a fundamental approach for industries which have to consider the variable environment during the design process. Waste management is one of the most important aspects to be handled, to reduce the disposal in landfills and to encourage the sustainable 3R approach: Reuse, Recycling and Remanufacturing. Product disassembly is an essential phase of the product lifecycle, necessary to evaluate the End-of-Life (EoL) strategies and to reduce environmental impact. In order to minimize the impact on production and costs it is very important to consider EoL scenarios during the embodiment design phase, when designer’s decisions influence product structure. Design for Disassembly (DFD) is a powerful method to reduce disassembly time and costs. However, there are no useful tools which provide guidelines to improve the product disassemblability or promote specific EoL scenarios.

For these reasons this paper describes an innovative Design for Disassembly approach and related tool to support designers in product disassemblability evaluation. The tool has the scope to manage EoL scenarios for industrial waste in the early design phases and to share metadata with the traditional design tools. Disassembly costs is one of the most important parameters during the evaluation of EoL scenarios. Six indices are presented to evaluate the economic and environmental feasibility of the EoL strategies. The calculation of the six indices permits alternative EoL scenarios to be compared and encourage the recyclability, reusability or re-manufacturability of a product. These evaluations can be used to foster a particular EoL scenario, as early on as in the design process. The preliminary analysis on mechatronic products underline the utility of the software tool and indices. Product re-design, realized using this approach, shows a relevant decrease in environmental impacts and disassembly costs. As a consequence, the new product has a relevant percentage of components with a closed-loop lifecycle.
The VR Session Manager: A Tool to Co-Ordinate a Collaborative Product Development Process in a Virtual Environment
Authors: Stelzer Ralph , Steger Wolfgang , Petermann Dirk
Published: September 2013

The paper elucidates a process integration method in which the virtual reality (VR) application moves beyond being just a visualisation tool to functioning as an interface for collaboration. The central module of this system is the so-called session manager. The session manager co-ordinates the collaboration of several authorised individuals and various software tools all working together on one development project. The session manager is at the centre of the product data management (PDM) system managing product structure, product documents and project state. The associated VR system synchronously presents the current state of the project. It is thus possible to visualise changes in geometry, appearance or structure in real time.

In this way, VR can be integrated into a heterogeneous system consisting of CAD workstations and simulation applications. Integration is based on a bi-directional link among all applications via the PDM system. Thus, it is possible to use and represent not only the product’s design and structure, but also its non-geometric information using PDM. Additionally, the persons working with it may select product components in VR and assign tasks to workstations or persons, since, in VR, relevant information from the PDM is available.
A SysML-Based Language for Modeling System-Level Architecture Selection Decisions
Authors: Kerzhner Aleksandr A. , Paredis Christiaan J. J.
Published: September 2013

Modern systems are difficult to design because of a need to satisfy many different stakeholder concerns from a number of domains, which require a large amount of expert knowledge. Current systems engineering practices try to simplify the design process by providing practical approaches to manage the large amount of knowledge and information needed during the process. Although these methods make designing a system more practical, they do not support a structured decision making process, especially at early stages when designers are selecting the appropriate system architecture, and instead rely on designers using ad hoc frameworks that are often self-contradictory, i.e., they can lead to alternative orderings where alternative A is better than alternative B is better than alternative C which is then better than alternative A. In order to support a more rational design making process, designers need to explicitly model the architecture selection decision and related knowledge. Then computational tools can be applied to guide the decision making. As a first step toward this more comprehensive modeling approach, in this paper a language is presented for modeling system-level architecture decisions by capturing the relevant domain-specific knowledge. This language is based on the principles of decision-based design and decision theory, where decisions are made by picking the alternative, which results in the most preferred expected outcomes. Therefore, the language is designed to capture potential alternatives in a compact form, analysis knowledge used to predict the quality of a particular alternative, and evaluation criteria to differentiate between outcomes. This language is based on the Object Management Group’s System Modeling Language (SysML). Where possible, existing SysML constructs are used and when additional constructs are needed SysML’s profile mechanism is used to extend the language. The value of the language is demonstrated by using it to represent a simple architecture selection decision of the actuation subsystem of a hydraulic excavator. Since this language models the architecture decision in a form that is computer interpretable, model transformations can be used to generate relevant analyses that can guide the decision maker during the design process.
Optimal Process Architectures for Distributed Design Using a Social Network Model
Authors: Cormier Peter , Devendorf Erich , Lewis Kemper
Published: September 2013

Distributed design systems fundamentally preserve individual design subsystem secrecy by limiting communication across subsystems. The natural secrecy of distributed design makes it difficult for design process managers to determine the appropriate order of subsystems in the design process. In this paper, we discuss a social network theory based heuristic to prescribe the optimal order of design subsystems. We call the order of the design subsystems process architecture and we leverage concepts like ‘distance,’ ‘bridging,’ and degree centrality’ to analyze the aggregate design system and identify preferable solution process architectures. Our network theory approach only requires a manager to know which subsystems share design information. We distinguish this research from previous work by empirically validating the heuristic against a genetic algorithm for 80 randomly generated distributed design systems. The heuristic performs well against the genetic algorithm and beats it in the majority of cases. Moreover, it does so without requiring any function evaluations.
An Overview of Sustainability Indicators and Metrics for Discrete Part Manufacturing
Authors: Kim Duck Bong , Leong Swee , Chen Chin-Sheng
Published: September 2013

Sustainable manufacturing has become an emerging environmental, economic, societal, and technological challenge to the industry, the academia, and the government entities. Numerous research and development (R&D) efforts have been launched, and many global and domestic efforts have been initiated toward a long-term sustainable world. This paper provides an overview of R&D efforts in the measurement of manufacturing sustainability, based on an intensive literature search. It focuses on sustainability metrics that apply to unit machining processes for discrete part manufacturing. The authors present results from assessing the scope of indicators that exist for sustainability measurement in general, with a quick visit to the taxonomy of manufacturing activities and different classifications of existing SM metrics by unit machining processes. Most metrics at the unit machining level were developed to measure environmental impacts with respect to energy, materials, water, wastes, and air emissions, while a relatively smaller effort was developed to gauge societal or economic impacts. We report on an analysis of energy metrics available for various unit machining processes at the sub-device and sub-unit process level.
Steps in Transforming Shapes Generated With Generative Design Into Simulation Models
Authors: Hooshmand Amir , Campbell Matthew I. , Shea Kristina
Published: September 2013

This paper introduces a platform that combines shape grammars with conventional simulation and analysis methods. The premise of this combination is to create an approach to synthesizing optimal shapes considering criteria requiring heat transfer and stress analysis for their evaluation. The necessary mechanisms and issues for integrating shape grammars with standard simulation systems are described. The benefits, challenges and future outlook of this approach with regards to traditional design synthesis systems are explored. Further, possible future research projects to extend the work are presented.
Preliminary Validation of Composite Material Constitutive Characterization
Authors: Michopoulos John G. , Iliopoulos Athanasios , Hermanson John C. , Orifici Adrian C. , Thomson Rodney S.
Published: September 2013

This paper is describing the preliminary results of an effort to validate a methodology developed for composite material constitutive characterization. This methodology involves using massive amounts of data produced from multiaxially tested coupons via a 6-DoF robotic system called NRL66.3 developed at the Naval Research Laboratory. The testing is followed by the employment of energy based design optimization principles to solve the inverse problem that determines the unknown parameters of the constitutive model under consideration. In order to validate identified constitutive models, finite element simulations using these models were exercised for three distinct specimen geometries. The first geometry was that of the characterization coupon under multiaxial loading. The second was that of open hole specimens in tension. The final one was that of stiffened panel substructures under tension. Actual experimental data from testing all these specimens were collected by the use of load cells, full field displacement and strain methods and strain gauges. Finally, the theoretical predictions were compared with the experimental ones in terms of strain field distributions and load-strain responses. The comparisons demonstrated excellent predictability of the determined constitutive responses with the predictions always within the error band of the methods used to collect the experimental data.
Characterization and Modeling of Elastomeric Joints in Miniature Compliant Mechanisms
Authors: Vogtmann Dana E. , Gupta Satyandra K. , Bergbreiter Sarah
Published: September 2013

Accurate analysis models are critical for effectively utilizing elastomeric joints in miniature compliant mechanisms. This paper presents work toward the characterization and modeling of miniature elastomeric hinges. The modeling portion is achieved using finite element analysis (FEA). Also presented is a 2-dimensional pseudo rigid body (PRB) analytical model for these hinges. Characterization was carried out in the form of several experimental bending tests and tension tests on representative hinges in 5 different configurations. The results of these experiments were then compared to the same tests modeled using FEA. We have represented the experimental results using FEA to within 12% error. This allows the use of FEA to model more complicated mechanisms’ behavior with some assurance of accuracy. Based on these tests and FEA models, a simplified 2-dimensional PRB analytical model was developed, consisting of a torsional spring, a linear spring, and another torsional spring in series. These analytical models enable us explore large design spaces efficiently. The accuracy of this model for geometries without corner effects has been verified to within 3% error when compared to FEA models in bending, and 17% in tension.
Development of a Drive Cycle Simulation Model for Hybrid Powertrains
Authors: Vingbäck Johan , Jeppsson Peter
Published: September 2013

In this paper a modular numerical simulation model for hybrid powertrains is presented. The simulation model is based on common design parameters and measurements for fuel efficiency and vehicle performance. Implemented in Simulink, the main model is expandable to combine the strengths of different types of simulation tools. As the design process proceeds, parts of the model can gradually be replaced with instances containing one or more subsystem modelled in the appropriate tool, including CAD, FEA and MBD, incrementally increasing the accuracy of the model of the overall system yet keeping the simulation time reasonable. Subsystems can be replaced to support hardware input and/or output, resulting in a so-called hardware-in-the-loop simulation. The presented system has shown to be modular as all the components contain their physical properties and can be modified, replaced or reorganized without the modification of any other subsystem. The simulation model of the powertrain is easily modified in order to allow the simulation of multiple designs with the same components. The systeam also has the same information flow as would be observed in a physical powertrain.
Granular Dynamics Simulation on Multiple GPUs Using Domain Decomposition
Authors: Mazhar Hammad , Seidl Andrew , Shotwell Rebecca , Quadrelli Marco B. , Negrut Dan , Jain Abhinandan
Published: September 2013

This paper describes the software infrastructure needed to enable massive multi-body simulation using multiple GPUs. Utilizing a domain decomposition approach, a large system made up of billions of bodies can be split into self-contained subdomains which are then transferred to different GPUs and solved in parallel. Parallelism is enabled on multiple levels, first on the CPU through OpenMP and secondly on the GPU through NVIDIA CUDA (Compute Unified Device Architecture). This heterogeneous software infrastructure can be extended to networks of computers using MPI (Message Passing Interface) as each subdomain is self-contained. This paper will discuss the implementation of the spatial subdivision algorithm used for subdomain creation along with the algorithms used for collision detection and constraint solution.
Incorporating Social Impact on New Product Adoption in Choice Modeling: A Case Study in Green Vehicles
Authors: He Lin , Chen Wei
Published: September 2013

While discrete choice analysis is prevalent in capturing consumers’ preferences and describing their choice behaviors in product design, the traditional choice modeling approach assumes that each individual makes independent decisions, without considering the social impact. However, empirical studies show that choice is social — influenced by many factors beyond engineering performance of a product and consumer attributes. To alleviate this limitation, we propose a new choice modeling framework to capture the dynamic influence from social network on consumer adoption of new products. By introducing the social influence attributes into the choice utility function, the social network simulation is integrated with the traditional discrete choice analysis in a three-stage process. Our study shows the need for considering social impact in forecasting new product adoption. Using hybrid electric vehicle as an example, our work illustrates the procedure of social network construction, social influence evaluation, and choice model estimation based on data from National Household Travel Survey. Our study also demonstrates several interesting findings on the dynamic nature of new technology adoption and how social network may influence consumers’ “green attitude” in hybrid electric vehicle adoption.
Implementation of an Efficient RMS Algorithm for Random Analysis in Vibrata™
Authors: Rupp Cory J. , Antal Gregory W.
Published: September 2013

When analyzing forced dynamic response to random excitation, obtaining root-mean-square (RMS) results without having to compute the underlying power spectral density (PSD) functions can significantly reduce solution time and memory usage. An algorithm for such calculations published by de la Fuente [1, 2] has been incorporated in ATA Engineering’s Vibrata™ program, a GUI- and text-file-driven modal dynamic analysis tool that works with Femap™ and MATLAB® to provide random, transient, harmonic, and response spectrum analysis. This paper describes some of the difficulties encountered in implementing this random response method and how they were overcome. It then shows two examples of the algorithm’s use in Vibrata and compares those computation times and solutions to standard PSD-based computations.
Application of Bayesian Sensor Placement Optimization for Real–Time Health Monitoring
Authors: Pourali Masoud , Mosleh Ali
Published: September 2013

Sensors are being increasingly used for real–time health monitoring of complex systems. The measured quantities are expected to provide real–time information about the state of the system, its subsystems, components, and internal and external physical parameters. A complex system normally requires many sensors to extract required information from the sensed environment. The increasing costs of aging systems and infrastructures have become a major concern and real–time health monitoring systems could ensure increased safety and reliability of these systems. Real–time system health monitoring, assesses the state of systems’ health and, through appropriate data processing and interpretation, can predict the remaining life of the system. This paper introduces a method based on Bayesian networks and attempts to find optimum locations of sensors for the best estimate a system health. Information metrics are used for optimized sensor placement based on the value of information that each possible sensor placement scenario provides.