bluuebunny/crossref_metadata_2025 huggingface dataset:
Fractional Model of a Gastrocnemius Muscle for Tetanus Pattern
Authors: Sommacal Laurent , Melchior Pierre , Cabelguen Jean-Marie , Oustaloup Alain , Ijspeert Auke Jan
Published: June 2008

This study talks about gastrocnemius muscle identification. During biological activation, every contractile structure is unsynchronized. Likewise, contraction and relaxation phases depend on all contractile elements, the activation type and the state of health. Moreover, gastrocnemius muscle is composed of three fibre types: Fast Fatigable (FF), Fast Resistant (FR) and Slow (S) fibres. Some recent works highlight a fractal structure of the muscle, which consolidate the approach based on the use of a non integer (or fractal) model to characterize its dynamic behavior. A fractional structure model, due to its infinite dimension nature, is particularly adapted to model complex systems with few parameters and to obtain a real time exploitable model. According to its complexity, muscle structure and activation mechanisms, and to these previous considerations, an identification based on fractional model is presented. A model is proposed for the tetanus pattern response in a high tiredness state. It is based on a multi-model structure, which corresponds to the decomposition in contraction and relaxation phases. This multi-model structure is expected to be included subsequently in agonist-antagonist structure.
Using CAD Models and Their Semantics to Prepare F.E. Simulations
Authors: Hamri Okba , Le´on Jean-Claude , Giannini Franca , Falcidieno Bianca
Published: June 2008

The preparation of simulation models from Computer Aided Design (CAD) models is still a difficult task since shape changes are often required to adapt a component or a mechanical system to the hypotheses and specifications of the simulation model. Detail removal or idealization operations are among the current treatments performed during the preparation of simulation models. Most of the time, model exchanges are required between the engineering office and the simulation engineers, often producing losses of information and lacking of robustness. Thus, inefficient processes and remodelling phases form the usual practice. In this paper we show that geometric models can be extracted from CAD software as well as some of their semantics. This semantics can then be transferred, used and eventually preserved during the shape adaptation process required for a given Finite Element Analysis (FEA). The software environment enabling this transfer simultaneously requires the description of the initial B-Rep NURBS model as well as that of the adapted one. The process set up is based on STandard for the Exchange of Product model data (STEP) to provide a robust link between CAD and shape adaptation environments. In order to describe the appropriate variety of shapes required for the Finite Element (FE) preparation, a specific data structure is proposed to express the corresponding topology of the models. Hence, it is shown that the operators associated to the FE preparation process can take advantage of this data structure and the semantics of the initial CAD model that can be attached to the adapted model. Examples illustrating the various process steps and corresponding operations are provided and demonstrate the robustness of the approach.
A Unified Information Model for Product Family Design Management
Authors: Nanda Jyotirmaya , Simpson Timothy W. , Shooter Steven B. , Stone Robert B.
Published: June 2008

A flexible information model for systematic development and deployment of product families during all phases of the product realization process is crucial for product-oriented organizations. In this paper we propose a unified information model to capture, share, and organize product design contents, concepts, and contexts across different phases of the product realization process using a web ontology language (OWL) representation. Representing product families by preconceived common ontologies shows promise in promoting component sharing while facilitating search and exploration of design information over various phases and spanning multiple products in a family. Three distinct types of design information, namely, (1) customer needs, (2) product functions, and (3) product components captured during different phases of the product realization process, are considered in this paper to demonstrate the proposed information model. Product vector and function component mapping matrices along with the common ontologies are utilized for designer-initiated information exploration and aggregation. As a demonstration, six products from a family of power tools are represented in OWL DL (Description Logic) format, capturing distinct information needed during the various phases of product realization.
The Influence of Same-Sign Cross-Coupled Stiffness on Rotordynamics
Authors: Ertas Bugra H. , Vance John M.
Published: June 2008

One of the main contributors to rotordynamic instability in modern day turbomachinery is cross-coupled stiffness. The terminology comes from the phenomenon in which the reactive stiffness force is normal to the rotor displacement. Cross-coupled stiffness (CCS) can be generated from fluid pressure forces in internal machine components such as gas/liquid seals, hydrodynamic bearings, axial flow turbomachinery stages, and centrifugal impellers. Some of these machine components exhibit a type of CCS that materializes as a follower-force, which is normal to the whirl orbit radius and therefore tangent to a circular whirl orbit. With the follower force collinear with the whirl velocity, energy is fed into the motion and makes it grow larger with time. This destabilizing force can be represented in a Newtonian coordinate system by opposite-sign CCS, Kxy = −Kyx. However, there are cases of CCS where the forces produced are not always in the direction of rotor whirl, and the net work of the force per cycle is zero. These CCS forces are purely distortive to the orbit and are not de-stabilizing. They are represented by same-sign CCS, Kxy, Kyx, not necessarily equal. This paper investigates the effects of same-sign CCS on rotordynamics. Experiments are presented that show the measurement of same-sign CCS on a pocket damper seal and the required testing scheme to determine the effect on rotordynamic stability.
Control in Delayed Stochastic Systems
Authors: Ohira Toru , Hosaka Tadaaki
Published: June 2008

This article discusses issues of controlling in situations where fluctuations and delay are present. A new paradigm for control schemes, termed “delayed stochastic controls”, is proposed for use in such situations.
Towards Rapid Redesign: Decomposition Patterns for Large-Scale and Complex Redesign Problems
Authors: Chen Li , Li Simon , Macwan Ashish
Published: June 2008

In an effort to develop a decomposition-based rapid redesign methodology, this paper introduces the basis of such a methodology on decomposition patterns for a general redesign problem that is computation-intensive and simulation-complex. In particular, through pattern representation and quantification, this paper elaborates the role and utility of the decomposition patterns in decomposition-based rapid redesign. In pattern representation, it shows how a decomposition pattern can be used to capture and portray the intrinsic properties of a redesign problem. Thus, through pattern synthesis, the collection of proper decomposition patterns allows one to effectively represent in a concise form the complete body of redesign knowledge covering all redesign problem types. In pattern quantification, it shows how a decomposition pattern can be used to extract and convey the quantum information of a redesign problem using the pattern characteristics. Thus, through pattern analysis, the formulation of an index incorporating two redesign metrics allows one to efficiently predict in a simple manner the amount of potential redesign effort for a given redesign problem. This work represents a breakthrough in extending the decomposition-based solution approach to computational redesign problems.
Towards Rapid Redesign: Pattern-Based Design Diagnostics for Large-Scale and Complex Redesign Problems
Authors: Chen Li , Macwan Ashish
Published: June 2008

This paper presents our continued research efforts towards developing a decomposition-based solution approach for rapid computational redesign to support agile manufacturing of evolutionary products. By analogy to the practices used for physical machines, the proposed approach involves two general steps: diagnosis and repair. This paper focuses on the diagnosis step. for which a two-phase decomposition method is developed. The first phase, called design dependency analysis, systematizes and reorganizes the intrinsic coupling structure of the existing design model by analyzing and reordering the design dependency matrix (DDM) used to represent the functional dependence and couplings inherent in the design model. The second phase, called redesign partitioning analysis, uses this result to generate alternative redesign pattern solutions through a three-stage procedure. Each pattern solution delimits the portions of the design model that need to be re-computed. An example problem concerning the redesign of an automobile powertrain is used for method illustration. Our seed paper has presented a method for selecting the optimal redesign pattern solution from the alternatives generated through redesign partitioning analysis, and a sequel paper will discuss how to generate a corresponding re-computation strategy and redesign plan (redesign shortcut roadmap).
Towards Rapid Redesign: Pattern-Based Redesign Planning for Large-Scale and Complex Redesign Problems
Authors: Chen Li , Li Simon
Published: June 2008

We have developed a decomposition-based rapid redesign methodology for large, complex computational redesign problems. While the overall methodology consists of two general steps: diagnosis and repair, this paper focuses on the repair step in which decomposition patterns are utilized for redesign planning. Resulting from design diagnosis, a typical decomposition pattern solution to a given redesign problem indicates the portions of the design model necessary for re-computation as well as the interaction part within the model accountable for design change propagation. Following this, this paper suggests repair actions with an approach derived from an input pattern solution, to generate a redesign roadmap allowing for taking a shortcut in the redesign solution process while scheduling re-computing tasks. To do so, a complete collection of re-computation strategies able to handle all possible decomposition patterns for any given redesign problem is introduced, and a two-stage redesign planning approach from re-computation strategy selection to redesign roadmap generation is proposed. An example problem concerning the redesign of a relief valve is used for illustration and validation.
A New Development of Multi-to-One Cell-Matching Method and Its Application in VOF Interface Tracking
Authors: Xiao Yumin , Amano R. S.
Published: June 2008

A new algorithm—multi-to-one cell matching method for interface tracking in volume-of-fluid (VOF) calculation is presented. This method is based upon unstructured grid and implemented on cells having quadrilaterals or hexahedrons origin. This method utilizes the geometrical characteristic of each vertex in an arbitrary cell to classify the vertex type and to group faces into four (two dimensional) or six (three dimensional) groups. The final regrouped arbitrary cells have the similar geometric information and VOF distributions as that of quadrilaterals or hexahedrons. Convective flux to solve the volume evolution equation can then be exactly evaluated. The method was implemented on unstructured adaptive mesh for VOF simulation. Numerical results for those test problems provide evidence for the algorithm’s quality, and accuracy.
Synthesis of Bistable Periodic Structures Using Topology Optimization and a Genetic Algorithm
Authors: Prasad Jitendra , Diaz Alejandro
Published: June 2008

Formulations for the automatic synthesis of two-dimensional bistable, compliant periodic structures are presented, based on standard methods for topology optimization. The design space is parameterized using non-linear beam elements and a ground structure approach. A performance criterion is suggested, based on characteristics of the load-deformation curve of the compliant structure. A genetic algorithm is used to find candidate solutions. A numerical implementation of this methodology is discussed and illustrated using a simple example.
Multi-Objective Design Optimization for Product Platform and Product Family Design Using Genetic Algorithms
Authors: Akundi Satish V. K. , Simpson Timothy W. , Reed Patrick M.
Published: June 2008

Many companies are using product families and platform-based product development to reduce costs and time-to-market while increasing product variety and customization. Multi-objective optimization is increasingly becoming a powerful tool to support product platform and product family design. In this paper, a genetic algorithm-based optimization method for product family design is suggested, and its application is demonstrated using a family of universal electric motors. Using an appropriate representation for the design variables and by adopting a suitable formulation for the genetic algorithm, a one-stage approach for product family design can be realized that requires no a priori platform decision-making, eliminating the need for higher-level problem-specific domain knowledge. Optimizing product platforms using multi-objective algorithms gives the designer a Pareto solution set, which can be used to make better decisions based on the trade-offs present across different objectives. Two Non-Dominated Sorting Genetic Algorithms, namely, NSGA-II and ε-NSGA-II, are described, and their performance is compared. Implementation challenges associated with the use of these algorithms are also discussed. Comparison of the results with existing benchmark designs suggests that the proposed multi-objective genetic algorithms perform better than conventional single-objective optimization techniques, while providing designers with more information to support decision making during product family design.
Bridging Cross-Domain Terminology for Biomimetic Design
Authors: Chiu I. , Shu L. H.
Published: June 2008

This work aims to improve creativity and innovation in design by facilitating the use of cross-domain analogies, particularly from biological phenomena, as stimulus for concept generation. Rather than create an enormous database of biological knowledge to specifically support engineering design, we have chosen to take advantage of the large amount of biological knowledge already in natural-language format, e.g., books, journals, etc. Relevant biological analogies for any given design problem are found by searching for instances of functional keywords that describe the intended effect of the design solution in a natural-language corpus. However, the optimal choice of keywords, or search terms, is complicated by the fact that engineers and biologists may use differing domain-specific lexicons to describe related concepts. Therefore, an engineer without sufficient background in biology may not be able to identify keywords with biological connotation that are not obviously related to the engineering keywords. This paper describes efforts to bridge the gap in lexicons by examining words that frequently collocate with searched words. The biological meaningfulness of these bridge words is characterized by how frequently they occur within definitions of biological terms in a biology dictionary. Search words identified this way may not be obvious to domain novices, and may parallel those suggested by domain experts, thus facilitating the use of cross-domain ideas to support design. Our approach of generating bridge words with biological meaningfulness is generic and can be used to bridge any disparate domains (e.g., engineering and economics). Thus designers are enabled to quickly access relevant concepts from different domains to produce more innovative solutions.
General Formulation of an Efficient Recursive Algorithm Based on Canonical Momenta for Forward Dynamics of Closed-Loop Multibody Systems
Authors: Naudet Joris , Lefeber Dirk
Published: June 2008

In previous work, a method for establishing the equations of motion of open-loop multibody mechanisms was introduced. The proposed forward dynamics formulation resulted in a Hamiltonian set of 2n first order ODE’s in the generalized coordinates q and the canonical momenta p. These Hamiltonian equations were derived from a recursive Newton-Euler formulation. It was shown how an O(n) formulation could be obtained in the case of a serial structure with general joints. The amount of required arithmetical operations was considerably less than comparable acceleration based formulations. In this paper, a further step is taken: the method is extended to constrained multibody systems. Using the principle of virtual power, it is possible to obtain a recursive Hamiltonian formulation for closed-loop mechanisms as well, enabling the combination of the low amount of arithmetical operations and a better evolution of the constraints violation errors, when compared with acceleration based methods.
Probabilistic Analytical Target Cascading: A Moment Matching Formulation for Multilevel Optimization Under Uncertainty
Authors: Liu Huibin , Chen Wei , Kokkolaras Michael , Papalambros Panos Y. , Kim Harrison M.
Published: June 2008

Analytical target cascading (ATC) is a methodology for hierarchical multilevel system design optimization. In previous work, the deterministic ATC formulation was extended to account for uncertainties using a probabilistic approach. Random quantities were represented by their expected values, which were required to match among subproblems to ensure design consistency. In this work, the probabilistic formulation is augmented to allow introduction and matching of additional probabilistic characteristics. Applying robust design principles, a particular probabilistic analytic target cascading (PATC) formulation is proposed by matching the first two moments of random quantities. Several implementation issues are addressed, including representation of probabilistic design targets, matching interrelated responses and linking variables under uncertainty, and coordination strategies for multilevel optimization. Analytical and simulation-based optimal design examples are used to illustrate the new PATC formulation. Design consistency is achieved by matching the first two moments of interrelated responses and linking variables. The effectiveness of the approach is demonstrated by comparing PATC results to those obtained using a probabilistic all-in-one (PAIO) formulation.
On the Framework of Information Processing in a Hand Motion Based Shape Conceptualization System
Authors: Varga Edit , Horva´th Imre , Rusa´k Zolta´n , Verlinden Jouke
Published: June 2008

In the computer support of conceptual design hand motions can be effectively used to express shapes and shape related operations. The development of these systems are challenging because of the special characteristics of conceptual design, such under-determinism, need of fast feedback and support of collaboration. This paper proposes a framework for information processing in a system, where a collaborating team of designers use hand motions to conceptualize shapes of various products. We separated the functions of the system into four groups: (1) data acquisition, where the hand motions are tracked as motion trajectories of dedicated joints of the hands and arms, (2) information completion, where the motion trajectories are processed and additional information is generated with the help of an upper limb model, (3) information conversion, where the motion trajectories are converted to surface information or shape manipulation operation and (4) visualization, where the generated surface is presented to the user. The modules of the system and the information flows were defined. A feasibility study was completed to qualify the alternative solutions for operational criteria. Measures were defined to describe the criteria and indices were created to enable a comparison. We concluded that (1) the criteria of each function should be fulfilled with regards to the final goal and (2) when multiple criteria are defined for each function, they may have an effect on each other, which has to be considered when selecting an optimal solution. Future research will focus on the software implementation of the proposed framework.
End Effects and Dynamic Equivalence in Elastic Waveguides
Authors: Karp Baruch
Published: June 2008

A normal-mode representation of waveguide behavior is recapitulated in terms of inner and outer responses in order to enhance the analogy with quasi-static beam solutions. This setting is employed to assist in the extension of the classical Saint-Venant’s principle to dynamic problems. The surface load parameters which determine the inner solution in a waveguide with free surfaces, are identified as the frequency and the average power of the load, provided the frequency is low enough and for purely symmetric (or purely antisymmetric) loads. A quantitative estimate of the extension of end effects is given. The one to one correspondence between the equivalent loads and the inner solution is used to reformulate the dynamic analogue of Saint-Venant’s principle.
Passive Control of Vibration of Elastically Supported Beams Subjected to Moving Loads
Authors: Younesian D. , Esmailzadeh E. , Kargarnovin M. H.
Published: June 2008

Vibration suppression of elastically supported beams subjected to moving loads is investigated in this work. For a Timoshenko beam with an arbitrary number of elastic supports, subjected to a constant axial compressive force, and having a tuned mass damper (TMD) installed at the mid-span, the equations of motion are derived and using the Galerkin approach the solution is sought. The optimum values of the frequency and damping ratio are determined both analytically and numerically and presented as some design curves directly applicable in the TMD design for bridge structures. To show the efficiency of the designed TMD, computer simulation for two real bridges, subjected to a S.K.S Japanese high-speed train, is carried out and the results obtained are compared for before and after the installation of the TMD system.
Using Violin “Engineering” to Create Innovative Lecture Demonstrations to Actively Engage Materials Science Students
Authors: Kitto Kathleen L.
Published: June 2008

An introductory Materials Engineering course can be challenging for students since in that course it is often the first time where students must integrate their knowledge of mathematics, chemistry and physics to solve a wide variety of complex and, at times, abstract problems. Finding new methods to teach the course content in order to more actively engage students is equally challenging for instructors. Two years ago, students at Western Washington University began to study part of the course content in materials engineering within the less abstract framework of acoustic/materials signatures of stringed musical instruments (particularly, violin “engineering”). Students can be actively engaged in this subject by posing a rather simple question. Why does a violin or guitar sound the way it does? Trying to answer that very question with materials science (and geometry) in class is a new way instructors may use in their course to more actively engage their students in materials science. This paper describes the use of violin “engineering” to create innovative lecture demonstrations and presentations illustrating acoustic and materials signatures as course supplements for any basic materials engineering course. These demonstrations require only the use of a laptop computer, the academic version of the Adobe Audition® software package (or equivalent), an inexpensive condenser type microphone, an inexpensive student stringed instrument (violin or guitar), and aluminum and wood vibrating plates. The paper gives the exact specifications for the various components needed to create these new lecture and/or lab demonstrations. The approach is innovative in that it takes a fundamental (and expensive) methodology normally used in the acoustic research of violins and other stringed instruments and translates it into a format that is not only affordable, but has also shown promise in our materials course to be a practical tool to actively engage students in materials science. Initial assessment data shows that the students are indeed more engaged in the course and there is measurable improvement in classical test question scores. Also, many students in the class have chosen to complete their research papers required for the class in these subjects; others have volunteered to work on undergraduate research projects investigating the materials signature of stringed instruments and new materials for such instruments. Geometry to create flat vibrating plates, including the top plate of a violin, is also given in the paper (the “violin.dxf” or “violin.igs” file is available upon request). A lengthy reference section is included so that additional demonstrations can be created by other instructors to satisfy their local materials engineering course needs.
Vibration of Beams With Unconventional Boundary Conditions Using Artificial Neural Network
Authors: Hassanpour Asl P. , Esmailzadeh E. , Mehdigholi H.
Published: June 2008

The vibration of a simply-supported beam with rotary springs at either ends is studied. The governing equations of motion are investigated considering the nonlinear effect of stretching. These equations are made non-dimensional and solved to the first-order approximation using the two known methods, namely, the multiple scales and the mode summation. The first five natural frequencies of the beam for different pairs of the boundary condition parameters are evaluated. A multilayer feed-forward back-propagation artificial neural network is trained using these natural frequencies. The artificial neural network used in this study shows high degree of accuracy for the natural frequency of the beam with general pairs of the boundary condition parameters.
Contact and Nonlinear Dynamic Modeling of a Ball Bearing for Motorcycle Engine System
Authors: Ryu Hansik , Yun Dukjin , Choi Jinhwan , Horiuchi Shigeru
Published: June 2008

In this paper, an analytical model is developed to describe the dynamic characteristics of a ball bearing in the motorcycle engine. In order to obtain accurate dynamic response of ball bearing, each ball is modeled as a rigid body which has radial and axial movement and rotational constraints. Beam element between outer race segments is used to consider flexibility of outer race. Beam deflection is calculated from beam forces and used for contact between ball and outer race. The contact surfaces of inner and outer race were represented by partial torus. The efficient contact search kinematics and algorithms in the context of the compliance contact model are implemented to detect the interactions between ball and race for the sake of speedy and robust solutions. Dynamic forces of balls and outer race are investigated from numerical results.
Conjugated-Order Differintegrals
Authors: Hartley Tom T. , Lorenzo Carl F. , Adams Jay L.
Published: June 2008

This paper introduces the concept of conjugated-order differintegrals. These are fractional derivatives whose orders are complex conjugates. These conjugate-order differintegrals allow the use of complex-order differintegrals while still resulting in real time-responses and real transfer-functions. Both frequency responses and time responses are developed. The conjugated differintegral is shown to be a useful representation for control design. An example is presented to demonstrate its utility.
Complex-Order Distributions
Authors: Hartley Tom T. , Adams Jay L. , Lorenzo Carl F.
Published: June 2008

This paper develops the concept of the complex order-distribution. This is a continuum of fractional differintegrals whose order is complex. Two types of complex order-distributions are considered, uniformly distributed and Gaussian distributed. It is shown that these basis distributions can be summed to approximate other complex order-distributions. Conjugated differintegrals are an essential analytical tool applied in this development due to their associated real time-responses. An example is presented to demonstrate the complex order-distribution concept. This work enables the generalization of fractional system identification to allow the search for complex order-derivatives that may better describe real time behaviors.
Vibration Analysis of a Brake Mechanism: Modeling, Simulation and Experimental Results
Authors: Dupac Mihaela A. , Raju P. K.
Published: June 2008

In this paper, an approach for identifying a model capable of representing the dynamics of the brake mechanism is presented. Experimentally acquired in-plane vibrations of the pad were analyzed using the non-linear dynamics method of Lyapunov exponents in order to characterize the system behavior. Friction-induced vibrations were then studied via the associated 4 DOF theoretical model of the brake system. Numerical simulations demonstrated that for a set of system parameters, a certain value of the slope of the mathematical characteristic between the dynamic friction coefficient and relative velocity, triggers the exponential growth of instability with an envelope in good agreement with that approximated from the experimental data. The results obtained from this study provide new insights into brake dynamics and the associated instability mechanisms.
A Case Study Contrasting German Systematic Engineering Design With Affordance Based Design
Authors: Maier Jonathan R. A. , Fadel Georges M.
Published: June 2008

In the young field of engineering design theory, various approaches to design differ in their conceptual bases, methods, and scope. These core differences make comparing design theories difficult. One strategy to overcome these differences, long used in the social sciences to test and compare theories, is the case study. In this paper we adopt a published design project, that of a computer monitor stand, and use it as a case study to compare two design theories. The design project was originally conducted using a form of German Systematic Engineering Design (GSED). We contrast those original results with what is obtainable using Affordance Based Design (ABD). Important insights into the differences between these two design theories quickly emerge. Among the differences found are the ways in which: customer needs data is interpreted and handled, product characteristics are represented, customer needs data flows into the ideation and selection processes, and bound and target data are utilized. Perhaps the most important difference shown is at what stage, and how, the product architecture is designed. In GSED, typically the product architecture arises in a bottom-up fashion from a combination of various sub-function solution principles. However, in ABD, the product architecture is the first subject of ideation and selection, as the high-level architecture determines in a top-down fashion most of the lower-level affordances that are designed subsequently. While no two design projects, design teams, or design methods are the same, it is hoped that this particular case study elucidates some of the salient differences between an established and a nascent design theory.
Style Design Method Based on Form Impressions
Authors: Nordgren Andreas , Aoyama Hideki
Published: June 2008

The automotive industry is very competitive and companies are spending enormous amounts of resources on the development of new cars. The success of a new model is highly correlated to how well the designers and engineers have been able to blend features, functionality, quality and design to bring an attractive car to a certain segment of the market at the right time. Furthermore, as modern manufacturing techniques have enabled most manufacturers to offer standard features in their cars, the design has become a major selling point and one of the key factors for the ‘image’ associated with a company. However, the image, or form impression of a car, stated in natural language, is subtle and difficult to directly relate to concrete design parameters. With few tools to address this issue, designers are left to rely on their experience and sensitivity to current trends in order to meet the customer expectations for a new model. The purpose of the method reported in this paper is to provide a foundation for a design support system, which can help designers visualize and validate the complex relationship between form impressions and design parameters. This was achieved by expressing form impressions in natural language as sets of 10 weighted attributes. 14 design parameters were established to describe the basic shape of a car and data on the form impression for 31 different shapes was collected via a survey designed by the Taguchi method. Factor analysis was performed to extract correlated factors and eliminate the overlap of meaning between attributes. A neural network, able to relate form impressions expressed in these factors to basic proportions of a car, was created, trained and used to generalize design parameters corresponding to any form impression presented to it. Finally, a 3D-model with the desired form impression was automatically created by the CAD-system outlined in this paper. These results show that this method can be used to create a design support system, which has a sensibility to the form impressions various shapes will give.
Correction of Motion Capture Data With Respect to Kinematic Data Consistency for Inverse Dynamic Analysis
Authors: Seemann Wolfgang , Stelzner Gu¨nther , Simonidis Christian
Published: June 2008

Inverse dynamics analysis of human motion requires that the trajectories of the selected anatomical points are known. Therefore, standard motion capture technique by tracking marker points is generally used to obtain the trajectories. The tracking process, however, introduces high-frequency noise into the trajectories and the measured data can not be used directly to proceed in the inverse dynamic analysis. A mechanical system is consistent with kinematic data if the constraint equations of position and their time derivatives are satisfied by any parameters contained in the data set. Spurious reaction forces result from violations of the constraint equations using non consistent data. Therefore, a method is applied in this paper, whereby a new set of trajectories is generated by performing a projection of the observed positions, velocities and accelerations onto the corresponding constraint manifold to ensure the consistency of the data mentioned above. Finally, the kinematics of the system is described with the corrected data set.
Design Optimization of Continuous Caster Refractory Components
Authors: Craig K. J. , de Kock D. J. , de Wet G. J. , Haarhoff L. J. , Pretorius C. A.
Published: June 2008

The paper describes the design optimization of different refractory components used in the continuous casting process. In the first case, an impact pad of a continuous caster tundish is optimized for its turbulence suppression capability, while the inclusion particle trapping of the design is monitored. The impact pad is used in isolation as the only tundish furniture component. In the second case, the Submerged Entry Nozzle (SEN) of the continuous caster mold is optimized for minimum meniscus turbulent kinetic energy (i.e., stable meniscus). In both cases, the design variables are geometrical in nature. The steady-state flow and thermal patterns in the tundish and mold are obtained using the commercial CFD solver FLUENT. In order to perform optimization, the geometries are parameterized and incorporated into a mathematical optimization problem. FLUENT and its pre-processor GAMBIT are linked to a commercial design optimization tool, LS-OPT, to automatically improve the designs using metamodel approximations. The optimization results show a reduction of 12.5% in the turbulence on the slag layer of the tundish, while for the SEN, the results for one design iteration only are shown, due to the high cost of the function evaluations. The final paper will contain additional results. The SEN base and improved designs are validated using water modeling.
Aspects of Osillations of Beams and Plates
Authors: Zarubinska Mariya A. , van Horssen W. T.
Published: June 2008

In this paper some initial boundary value problems for beam and plate equations will be studied. These initial boundary values problems can be regarded as simple models describing free oscillations of plates on elastic foundations or describing coupled torsional and vertical oscillations of a beam. An approximation for the solution of the initial-boundary value problem will be constructed by using a two-timescales perturbation method. For the plate on an elastic foundation it turns out that complicated internal resonances can occur for specific parameter values.
Analysis Methods for the Motion and Vibration of a Moving Body on the Complicated 3D Trajectory
Authors: Fujita Katsuhisa , Funakoshi Yuji , Nakagawa Chihiro
Published: June 2008

We investigate the motion and vibration of a moving body on a complicated 3 dimensional trajectory. We take a roller coaster as a model of a moving body. Equations of its motion and conditions of constraints are set up for using the differential-algebraic equation (DAE). In our previous reports, we showed the simulation method by using the s-u-z coordinate. Let us call it the s-u-z simulation method. s-axis is the direction of a length of trajectory which is tangential line for the projected trajectory on coordinate x-y. In this paper, we examine the simulation method by using the global coordinate x-y-z. Let us call it the x-y-z simulation method. In the process of the simulation, we apply the stablization method by Baumgarte to the both of simulation methods. It is found that the x-y-z simulation method is more complicated than the s-u-z simulation method so that it is more difficult to stablize the simulated trajectory in the x-y-z simulation method. Lastly, we compare these response accelerations in each simulation method with those in experiment.
A Methodology to Manage Uncertainty During System-Level Conceptual Design
Authors: Martin Jay D. , Simpson Timothy W.
Published: June 2008

Current design decisions must be made while considering uncertainty in both models and inputs to the design. In most cases this uncertainty is ignored in the hope that it is not important to the decision making process. This paper presents a methodology for managing uncertainty during system-level conceptual design of complex multidisciplinary systems. The methodology is based upon quantifying the information available in computationally expensive subsystem models with more computationally efficient kriging models. By using kriging models, the computational expense of a Monte Carlo simulation to assess the impact of the sources of uncertainty on system-level performance parameters becomes tractable. The use of a kriging model as an approximation to an original computer model introduces model uncertainty, which is included as part of the methodology. The methodology is demonstrated as a decision making tool for the design of a satellite system.
An Iwan Model for Dissipation in Structural Systems With Frictional Joints
Authors: Miller Jason D. , Quinn D. Dane
Published: June 2008

Modeling mechanical joints in an accurate and efficient manner is of great importance in the analysis of large structural systems, which can be composed of a large number of connected components. This work presents an interface model that can be decomposed into a series-series Iwan model together with an elastic chain, subject to interfacial shear loads. The model is developed and results are presented as the interface is subject to harmonic loading of varying amplitude. The model presented is able to qualitatively reproduce experimentally observed dissipation scalings. Finally, the interface model is embedded within a larger structural system to illustrate its effectiveness in capturing the structural damping induced by mechanical joints.
Superharmonic Resonance of Order 2 for an Impacting Hertzian Contact Oscillator: Theory and Experiments
Authors: Perret-Liaudet Joe¨l , Rigaud Emmanuel
Published: June 2008

The purpose of this paper is to investigate experimental responses of a preloaded vibroimpact Hertzian contact to an order 2 superharmonic excitation. A test rig is used, corresponding to a double sphere-plane contact preloaded by the weight of a moving body. Typical response curves are obtained kinder the superharmonic excitation. The Hertzian non linearity constitutes the precursor of vibroimpacts established over a wide frequency range. This behaviour can be related to the existence of a transcritical bifurcation. In conjuction with the experiments, numerical results lead to the same conclusion. In particular, the threshold level of the excitation necessary to induce vibroimpact is confirmed.
A Cooperative-Collaborative Design System for Multi-Disciplinary Mechanical Design
Authors: Chen Zhiqiang , Siddique Zahed
Published: June 2008

The emergence of computer and network technology has provided opportunities for researchers to construct and build systems to support dynamic, real-time, and collaborative engineering design in a concurrent manner. This paper provides an understanding of the product design in a distributed environment where designers are in different geographic locations and are required to be involved in the design process to ensure successful product design. A design process model that captures the major interactions among stakeholders is presented, based on the observation of cooperation and collaboration. The stakeholders’ interactions are divided into activity and system level to distinguish the interactions in group design activities and design perspective evolution. An initial computer implementation of the design model is presented. The design system consists of a set of tools associated with design and a management system to facilitate distributed designers to support various design activities, especially conceptual design. Our research emphasis of design collaboration in this paper is: (i) Model a Cooperative-collaborative design process; (ii) Support synchronized design activities; and (iii) Structure the complex relations of various design perspectives from engineering disciplines.
Parameter Identification of a Nonlinear Joint Within a Noise Path Synthesis Framework
Authors: Rook Todd
Published: June 2008

An efficient noise path synthesis (NPS) approach which has been previously developed has been enhanced by coupling it with a parameter identification (PI) scheme to estimate effective joint properties.
A Logarithmic Complexity Divide and Conquer Algorithm for Flexible Multibody Dynamics
Authors: Mukherjee Rudranarayan , Anderson Kurt
Published: June 2008

This paper presents an efficient algorithm for parallel implementation of multi-flexible-body dynamics systems simulation and analysis. The effective overall computational cost of the algorithm is logarithmic when implemented with a processor optimal O(n) processors. This algorithm formulates and solves the nonlinear equations of motion for mechanical systems with interconnected flexible bodies subject to small elastic deformation together with large rotations and translations. The large rotations or translations are modeled as rigid body degree of freedom associated with the interconnecting kinematic joint degrees of freedom. The elastic deformation of the component bodies is modeled through the use of admissible shape functions generated using standard finite element analysis software or otherwise. Apart from the approximation associated with the elastic deformations, this algorithm is exact, non-iterative and applicable to generalized multi-flexible chain and free topologies.
The Relationship Between Function and Affordance
Authors: Brown David C. , Blessing Lucienne
Published: June 2008

The purpose of this paper is to attempt to clarify the concept of affordances, as introduced by Maier and Fadel, to relate affordances to function, to try to reduce confusion about both of these terms by providing a detailed model, and to expose some of the existing research on function to a wider audience. The paper starts by constructing a model of function that relates devices to an environment. We then extend the model to include goals. Next we express the concept of affordances in terms of the model already constructed. The paper concludes by discussing the impact that use of affordances might have on the designer’s pattern of reasoning.
The Development of a Monitoring and Control System for Pulverised Coal Flames Using Artificial Intelligence Techniques
Authors: Tan Oui Hong , Wilcox Steven John , Ward John
Published: June 2008

This paper discusses the application of low cost sensors for monitoring pulverised coal flames. A series of burner diagnostics tests using Infra-red (IR), Microphone and Acoustic Emission (AE) sensors were conducted on a 150 kW pulverised fuel (pf) burner rig based at Casella CRE Ltd. in the United Kingdom. These experiments systematically varied the burner swirl number and the secondary airflow rate over a significant range for two different coals so that both satisfactory and ‘poor’ combustion conditions were obtained. The infra-red radiation from the flame, the combustion noise and the acoustic emission generated in the burner body were measured, as were the fuel and airflow rates and pollutant emissions. The signals from the sensors were analysed by using signal processing techniques to reveal a number of features. These in turn were compared with the three major combustion gases such as Nitrogen Oxides (NOx), Carbon monoxide (CO) and Oxygen (O2) followed by correlation coefficient analysis (CCA). It is envisaged that these sensors can be used for predicting gaseous emissions and will be particularly attractive for multiple burner installations where the pollutant emissions are often discharged through a common manifold, so that the individual burner performance is often not known and cannot be optimised.
Diagnosing Engineering Information Interoperability: Recognizing the Value of Standards-Based PLM — Part 1
Authors: Bajaj Manas , Kim Injoong , Mocko Gregory , Peak Russell , Udoyen Nsikan , Wilson Miyako , Greene David , Raines Buddy , Srinivasan Vijay
Published: June 2008

The notion of an open standards-based product lifecycle management (PLM) framework is gaining momentum. In this paper, we describe the idea of a standards-based collective product model (CPM) and its interaction with domain models native to typical engineering tools. A critical hurdle in the development of the CPM from domain models is assessing the compatibility of information in these native models to its corresponding standards-based representation. To address this, we use the concept of “degree-of-openness” of engineering information. This concept comprises three metrics, namely compatibility, coverage and completeness that are used to evaluate the interoperability of information in tool-specific models with its corresponding standards-based representation. We also demonstrate GT-Diagnostics, a prototype tool that evaluates these metrics. Using electrical and mechanical CAD examples, we illustrate the value of these metrics in understanding the relative interoperability of information for engineering and business decision making. Results indicate that the metrics help to identify the sources of incompatibility of information and the areas of possible improvement in the compared schemas.