bluuebunny/crossref_metadata_2025 huggingface dataset:
A Sensitivity-Enhancing Control Approach for Structural Model Updating
Authors: Jiang L. J. , Wang K. W. , Tang J.
Published: May 2009

Model updating plays an important role in structural design and dynamic analysis. The process of model updating aims to produce an improved mathematical model by correlating the initial model with the experimentally measured data. There are a variety of techniques available for model updating using dynamic and static measurements of the structure’s behavior. This paper focuses on the model updating methods using the measured natural frequencies of the structure. The practice of model updating using only the natural frequencies encounters two well-known limitations: deficiency of frequency measurement data, and low sensitivity of measured natural frequencies with respect to the physical parameters that need to be updated. To overcome these limitations, a novel model updating method is presented in this paper. First, closed-loop control is applied to the structure to enhance the sensitivity of natural frequencies to the updating parameters. Second, by including the natural frequencies based on a series of sensitivity-enhanced closed-loop systems, we can significantly enrich the frequency measurement data available for model updating. Using the natural frequencies of these sensitivity-enhanced closed-loop systems, an iterative process is utilized to update the physical parameters in the initial model. To demonstrate and verify the proposed method, case studies are carried out using a cantilevered beam structure. The natural frequencies of a series of sensitivity-enhanced closed-loop systems are utilized to update the mass and stiffness parameters in the initial FE model. Results show that the modeling errors in the mass and stiffness parameters can be accurately identified by using the proposed model updating method.
Capillary Flows of Highly Filled Epoxy/Ni Suspensions for Conductive Adhesive Applications
Authors: Zhou Jianguo , Sancaktar Erol
Published: May 2009

Epoxy/Ni adhesives can be used as integrated circuit (IC) packaging materials due to their lower cost than epoxy/Ag adhesives with acceptable electrical conductivity. In this study, stable and unstable capillary flows of highly filled epoxy/Ni suspensions were investigated with and without cure at room temperature, via the capillary rheometer and syringe extrusion. Variations of the bulk electrical conductivity in these processes were discussed as well. Axial filtration of the polymer binder occurs under the static pressure for Epon815C/Ni/DETA adhesive with 50 wt% of Ni in syringe, resulting in an unstable flow and a cross-sectional filler concentration or electrical conductivity gradient. In dynamic capillary extrusion, lower resin viscosity and apparent shear rates enhance the flow instability and filtering of polymeric binder for epoxy/Ni suspensions with 75 wt% of Ni, thus facilitating a change in bulk electrical conductivity during processing. With increasing shear rates, the force oscillation frequency and force magnitudes increase. Incorporation of Ni nanopowders promotes a stable flow, yet the occurrence of agglomerates somewhat nullifies this advantage. Additionally, different rheological behaviors result as cure proceeds with different resins. Also, occurrence of the agglomerates leads to flow instabilities during processing with cure.
Simultaneous Pedestrian and Robot Localization Technique in an Indoor Ubiquitous Robotic Space (URS)
Authors: Ahn Hyo-Sung , Yu Wonpil
Published: May 2009

This paper proposes a simultaneous localization technique of mobile robot and pedestrian in ubiquitous sensor network. For the robot localization, a dead-reckoning system is developed wherein odometer, magnetic compass, and heading angle rate sensor are used. The novelty of dead-reckoning system developed in this paper is that it does not use acceleration in motion dynamic equation. Since the dead-reckoning system does not use linear acceleration, the system is not affected by high frequency noise, which is usually contained in the accelerometer measurement. For the pedestrian tracking, ubiquitous sensor network such as IEEE 802.15.4 is used. In this paper, it is also assumed that the relative direction of the pedestrian from the mobile robot is measured on the robot platform. Extended Kalman filter is used to integrate the sensor measurements. Simulation results will be presented to demonstrate the superiority of the proposed simultaneous localization technique.
Mobile Manipulator Networks: Platform Development and Applications
Authors: Jensen Austin M. , Chen YangQuan
Published: May 2009

This paper presents a new platform with a team of lab-scale networked mobile robotic manipulators (SumoMote) which merges a mobile manipulator with wireless mobile sensor networks. Many existing platforms built for mobile manipulation are big and expensive. Our SumoMote is built small and inexpensive for applications where quantity is more important than size. The hardware and software of the SumoMote will be described. Then two application scenarios will be presented to illustrate SumoMote’s capability in mobile sensor networks and how the added manipulator can help.
A Transient Tire Model for Uneven Road Surface
Authors: Kim Seongho , Nikravesh Parviz E. , Gim Gwanghun
Published: May 2009

This study presents a transient tire model for tire vibration characteristics due to uneven road surfaces. The model is composed of two parts—a static circular beam and a dynamic rigid ring. A new contact algorithm is developed based on the circular beam model, which can estimate contact pressure distribution by solving a set of linear equations. Tire vibration characteristics are then represented by combining the rigid ring model to the circular beam. Examples of contact pressure distribution and tire transient behaviors due to cleat tests are demonstrated and compared with measured data.
Simulation Investigations of the Effect of a Supporting Structure Defect on the Dynamic State of the Rotor Supported on Slide Bearings
Authors: Z˙ywica Grzegorz
Published: May 2009

The present article reports an attempt to assess the effect of the defect having the form of supporting structure fracture on the dynamic state of the rotor supported on slide bearings. The investigations were conducted on an experimentally verified numerical model of a selected large-dimension rotating machine. Within the framework of the investigations, selected cases of a defect localised in the region of one of bearing supports were analysed. The applied method of calculations comprised two basic stages. The first stage consisted in determining complex flexibility characteristics of the supporting structure at the rotor foundation place. In the second stage the obtained flexibility characteristics, after transformation to real matrices of stiffness, damping, and apparent masses, were used for determining parameters of rotor motion. As a result of the calculations, characteristics were obtained that provide opportunities for assessing the effects of the examined defects on rotor vibrations within a wide range of rotational speeds.
Probabilistic Analysis of Static Response for Turbine Blade With Parametric Uncertainty
Authors: An L. Q. , Wang Z. Q.
Published: May 2009

A probabilistic analysis method is developed for static response of the turbine blade with parametric uncertainty. The material, geometric parameters and loadings of blade exhibit notable random fluctuations, so the conventional deterministic analysis of blade can’t provide complete information. The Stochastic analysis can tackle the uncertainties in blade parameters and obtain the probabilistic characteristics of the response. In this paper, the study focuses on the 3D stochastic finite element method (3DSFEM) of the static response for turbine blade. The perturbation stochastic finite element method (PSFEM) is used to calculate probabilistic characteristics of the static response of the turbine blade. The random response of a turbine blade subjected to the steam pressure and the centrifugal force is analyzed using perturbation stochastic finite element method. The example shows that the present method is valid.
Barriers to Creativity in Engineering Education: A Study of Instructors and Students Perceptions
Authors: Foley Stephany , Kazerounian Kazem
Published: May 2009

This paper studies “creativity” in engineering education, by examining the perception of instructors and students. We aims to identify factors that impede a creative environment (creativity blockers). The study entails review of established research in the fields of psychology and educational psychology to identify factors which create an educational environment conducive to creativity. These factors are formalized in the Ten Maxims of Creativity in Education, a set of criteria that constitute an educational environment conducive to fostering creativity in students. These maxims form the basis for our work in examining the contemporary engineering education. Extensive surveys are designed, created, distributed and statistically quantified to study the perceptions of engineering educators and students, in comparison to non-engineering educators and students. The results unfortunately show that the current engineering student experiences almost none of the Ten Maxims of Creativity as a part of their academic experience.
Optimization of a Platform With Respect to Force Contact Conditions
Authors: Bestle Dieter
Published: May 2009

Chimneys in operating power plants cannot be demolished in the classical way by dynamite. A new technology has been invented where they are cut off starting from the top, and where the pieces of the reinforced concrete chimney are dropped through the inner pipe of the chimney. In order to avoid the falling down of pieces on the outer side, a ring platform is attached to the chimney by pure force contact which allows semi-automatic climbing up and down. The paper addresses two crucial design decisions concerning the ring platform: the design of the contact geometry and the shape of the ring structure. Both design problems are formulated as multicriterion optimization problems where the first one can be solved partially in an analytical way whereas the second one has to be solved numerically. It will be shown how the problems can be formulated in various ways depending on the technical requirements.
Measurement of Transmission Error Using Rotational Laser Vibrometers
Authors: White Robert , Palan Vikrant
Published: May 2009

Transmission error is the quantity that best correlates with gear noise. Using gear inspection data, one can estimate transmission error, however actually measuring it is a substantial task. For the most part, there are two groups of people who measure transmission error: those doing gear inspection and researchers. While it could prove useful in gearbox development, it is rarely done in this context because the equipment required to make transmission error measurements doesn’t package well, is expensive, can be difficult to use and is generally not very flexible. Transmission error is usually measured on test stands built particularly for that reason. An alternative method for transmission error measurement is now available to the development engineer who desires to make this measurement on his gearbox (such as for transmission noise development). This technique makes use of two rotational laser vibrometers and a synchronous time averaging algorithm. The laser approach is particularly appealing because it requires very little modification to the gearbox. Furthermore, it allows one to access gears within the gearbox which do not extend through the gearbox walls. The laser approach, however, has some of its own special challenges, but when those are adequately addressed, one has the capability to measure transmission error between nearly any two gears in a gearbox.
Designing Distributed Compliant Mechanisms With Characteristic Stiffness
Authors: Chen Shikui , Wang Michael Yu
Published: May 2009

A novel method is proposed in this paper to address the cutting-edge problem of topology optimization of distributed compliant mechanisms, which requires the design to possess both large output displacements and evenly distributed compliance simultaneously. The design is represented by a level-set model that precisely specifies the distinct material regions and their sharp interfaces as well as the geometric boundary of the structure, capable of performing topological changes and capturing geometric evolutions at the interface and the boundary. Existing techniques for eliminating de facto hinges in the design are reviewed. Further, the intrinsic deficiencies in the widely used “spring model” are discussed and a new formulation considering the “characteristic stiffness” of the mechanism is proposed. The proposed method is demonstrated with benchmark examples of compliant mechanism optimization. The result is a design with evenly distributed compliance and a more desirable characteristic, which uniquely distinguishes our method.
Novel Autonomous Underwater Vehicle Based Upon Jellyfish Locomotion
Authors: Blanch Ian G. , Storti Duane W. , Anderson Rhonda L. , Ganter Mark A. , Reinhall Per G.
Published: May 2009

This paper describes the process of developing a novel biomimetic autonomous underwater vehicle (AUV) inspired by jellyfish locomotion. Our interest in an AUV that mimics jellyfish locomotion stems from the jellyfish’s simplistic and robust physiology and neurological makeup. Jellyfish swimming gates are controlled by a neural architecture consisting of an outer nerve ring and an inner nerve ring. The inner nerve ring is responsible for incorporating the sensory input from the outer ring and innervating the subumbrellar swimming muscles. Additionally, cells in the inner ring generate endogenous rhythms and act as pacemakers. The system of pacemakers generates the highly maneuverable swimming gates that can be observed in jellyfish; swimming vertically, turning and hovering. The swimming gates have been shown to correspond to the dynamics of the response of a system of coupled identical van der Pol oscillators. These oscillators are capable of creating in-phase, out-of-phase and “asymmetric” phase-locked dynamics that are plausibly related to the basic modes of jellyfish locomotion of coordinated bout swimming, hovering, and turning, respectively. In addition, the system of oscillators is fault tolerant; if the modeled system of oscillators is disrupted, analogous to sections of the jellyfish being damaged, the oscillators adjust and maintain effective swimming gates allowing the jellyfish to remain mobile. The simplicity and fault tolerance of the oscillatory system makes it an ideal model for a locomotion control system for an AUV. The objective of the Jellyfish AUV project is to emulate the locomotion and control mechanisms of the biological jellyfish to create a simple and robust AUV, which is both highly maneuverable and low in cost. The iterative design process that resulted in a working Jellyfish AUV is detailed in this paper. Numerous designs were created, exploring different combinations of actuator mechanisms, body types and control systems. Different actuators were evaluated for their ability to meet our design requirements. These actuators ranged from off the shelf servos to the more exotic shape memory alloys (SMAs) and ionic polymer metal composites (IPMCs.) By the completion of the prototyping phase of the Jellyfish AUV project we had created a low cost AUV using off the shelf components including, servos, linkages and a microprocessor based control system. The input to the servos was derived from a system of coupled oscillators which were tuned to mimic the observation jellyfish gates. In addition, using the Jellyfish AUV prototype, we showed that the identified servo input patterns roughly translate to swimming, hovering, and turning.
Bifurcation Analysis of a Microactuator Using a New Toolbox for Continuation of Hybrid System Trajectories
Authors: Kang Wonmo , Wilcox Bryan , Dankowicz Harry , Thota Phanikrishna
Published: May 2009

This paper presents the application of a newly developed computational toolbox, TC-HAT (TCˆ), for bifurcation analysis of systems in which continuous-in-time dynamics are interrupted by discrete-in-time events, here referred to as hybrid dynamical systems. In particular, new results pertaining to the dynamic behavior of an example hybrid dynamical system, an impact microactuator, are obtained using this software program. Here, periodic trajectories of the actuator with single or multiple impacts per period and associated saddle-node, perioddoubling, and grazing bifurcation curves are documented. The analysis confirms previous analytical results regarding the presence of co-dimension-two grazing bifurcation points from which saddle-node and period-doubling bifurcation curves emanate.
Adaptive Deposition Coverage Toolpath Planning for Metal Deposition Process
Authors: Ren Lan , Ruan Jianzhong , Eiamsa-ard Kunnayut , Liou Frank
Published: May 2009

Coverage toolpath planning is very critical to deposition quality in layered manufacturing especially for metal deposition processes. The correct choice of toolpath patterns will make it possible to build a fully dense and functional metal part. The major consideration when selecting a toolpath pattern is the complete coverage of the to-be-deposited geometry which means no voids should happen. This paper presents the research on the toolpath coverage efficiency and the strategies to predict the possibility of the occurrence of deposition voids so that the appropriate toolpath pattern can be applied to avoid deposition voids. The contour-parallel offsetting pattern and the adaptive zigzag toolpath pattern will be applied as the alternate options and the final adaptive deposition coverage toolpath will be the combination of these two basic patterns depending on the prediction results of the occurrence of the deposition voids. The experiment has demonstrated that the adaptive toolpath pattern can greatly improve the reliability of the coverage path planning in deposition processes.
Experimental Validation of Two Damping Force Models for the ANCF
Authors: Kim Hyun-Woo , Yoo Wan-Suk , Sohn Jeong-Hyun
Published: May 2009

Many researchers have studied computer-aided simulations of elastic bodies undergoing large deflections and large deformations. But there have been few attempts to validate the numerical formulations used in these studies. The main aim of this paper is to validate the absolute nodal coordinate formulation (ANCF) by comparing the results to experimental measurements on beams. Physical experiments with a highspeed camera were carried out to capture the large displacement of the beam and to verify the results of computer simulations. To consider the damping forces, Rayleigh’s damping and quadratic damping are employed and compared to the experimental results. Numerical results obtained from computer simulations were compared with the results from the physical experiments according to the 1st mode and the 2nd mode of the beam, respectively.
Vibration Suppression of Rotating Machinery Utilizing an Automatic Ball Balancer and Discontinuous Spring Characteristics
Authors: Liu Jun , Ishida Yukio
Published: May 2009

Automatic ball balancer is a balancing device where two balls inside a hollow rotor move to optimal rest positions automatically to eliminate unbalance. As the result, vibrations are suppressed to a small amplitude or a zero amplitude in the rotational speed range higher than the major critical speed. However, it has the following defects. The amplitude of vibration increases in the rotational speed range lower than the major critical speed. In addition, almost periodic motions with large amplitude occur due to the rolling of balls inside the rotor in the vicinity of the major critical speed. Due to those defects, the automatic ball balancer has not been used widely. This paper proposes the vibration suppression method utilizing the discontinuous spring characteristics together with an automatic ball balancer to suppress vibration and to overcome these defects of the automatic ball balancer. The validity of proposed method is confirmed theoretically, numerically and experimentally. The results show that amplitude of vibration can be suppressed to a small amplitude in the vicinity of the major critical speed and the zero amplitude in the range higher than the major critical speed.
An Efficient Numerical Method for Dynamic Interaction Analysis of Shinkansen Train and Railway Structure During an Earthquake
Authors: Tanabe M. , Matsumoto N. , Wakui H. , Sogabe M. , Okuda H. , Tanabe Y.
Published: May 2009

In this paper, a simple and efficient numerical method to solve for the dynamic interaction of a Shinkansen train (high-speed train in Japan) and railway structure during an earthquake is given. The motion of the train is modeled in multibody dynamics with nonlinear springs and dampers used to connect components. An efficient mechanical model for contact dynamics between wheel and rail during an earthquake is presented. The railway structure is modeled with various finite elements. A three-dimensional nonlinear spring element based on a trilinear elastic-plastic material model is given for the concrete railway structure during an earthquake. A loop structure model has been devised to obtain an approximated combined motion of the train and railway structure during an earthquake. A modal method has been developed to solve large-scale nonlinear equations of motion of the train and railway structure effectively. Based on the present method, a computer program DIASTARS for the dynamic interaction of a Shinkansen train and railway structure during an earthquake has been developed. Numerical examples are demonstrated.
On Solvability of Multibody Contact Problems
Authors: Ivanov Alexander P.
Published: May 2009

The paper is devoted to dynamic multi-rigid-body contact problems with dry friction. It is known that such problem may have multiple solutions or none solution (so-called Painleve´ paradoxes). A great deal of works concerning overcoming of the paradoxes was published last century, but general conditions of existence and uniqueness were not derived yet. We consider systems with a finite numbers of contact points with well-defined contact directions and Coulomb friction. The equations of motion contain unknowns of two kinds: the accelerations and the contact forces. According to the friction law, some of these variables vanish, and remaining ones can be treated as a coordinate system in the space of the generalized forces. Thus, this space splits to a finite number of regions with different coordinates. From a geometrical point of view, the solvability of the multi-contact problem means that the union of these regions equals to the whole space. Furthemore, the solution is unique ⇔ any pair of regions has empty intersection, and the coordinates within any region are defined uniquely. We present some algebraic conditions, which are equivalent to these geometric properties. Therefore, necessary and sufficient conditions of correct solution to multibody contact problem are obtained for the first time. A number of mechanical examples are considered to illustrate new results.
The Mathematical Model for the Generation of the Cylindrical Gear With Curved Cycloidal Teeth
Authors: Stanasel Iulian , Ghionea Adrian , Ghionea Ionut , Ungur Petru , Stanasel Oana
Published: May 2009

The performed studies regarding the cylindrical gears with curved teeth or in V showed that a uniform distribution of the load on the flanks is hard to realise, generally being necessary later finishing processing or modifying the gear by camber or flanking, which suppose supplementary expenses. On the basis of these mentions and taking into account the advantages of curved bevel gear, the purpose of this paper is to present an original study regarding the mathematical model for generation of a curved cylindrical gear with high performances. The cycloidal gear was chosen after a technical and an economical study regarding on the possibility of practical implementation with the lowest production costs using a special device, adapted on a Phauter processing machine of cylindrical gear. This was the main reason for choosing a cycloidal profile from several types of curved teeth (cycloidal arc, circle arc, Archimede’s spiral, involute arc). So, the main aim of the paper is to determine the equations of the flanks of cylindrical wheel with curved teeth in oblong cycloidal arc, in order to establish if the technical generation is possible. The curved cylindrical teeth with cycloidal flanks is generated by rolling with straight mobile line and continuous division by using a milling cutter with 1, 2, 3, 6 groups of knifes equidistantly placed, fixed on an adaptable device on a Phauter processing machine. The two curves which define the flank are simultaneously generated by correlated motions, and the flanks of the wheel part result as a roll of successive positions of generating hook materialized by the cutting edge of the tool. The shape of the contact curve between the conjugated surfaces of generating element and the wheel part can be obtained if you are taking into account the kinematic condition. Using this condition you can determine the relationship between the kinematic, geometric and technological parameters. The line of the flanks is studied in the reference plane and in parallel planes with this, and the profile of the flanks is determined in perpendicular planes on the work piece axis. Based on the parametric equations it was made the simulation program in MATLAB that indicates that this gears can be obtained, and constitutes the first step in practical manufacturing of this kind of gears. By analyzing the obtained shape they result useful conclusions for the manufacturing of the involute-tooth gear with curved oblong cycloidal arc. On the other hand, using Solid Edge it was made the spatial modeling of the cylindrical gear with curved cycloidal teeth that allows next FEA studies regarding on the contact and bending stress.
Recommending a Platform Leveraging Strategy Based on the Homogeneous or Heterogeneous Nature of a Product Line
Authors: Alizon Fabrice , Shooter Steven B. , Simpson Timothy W.
Published: May 2009

Platform-based product development depends on many factors, including technology, cost, competition, and life cycle considerations, and many companies would benefit from knowing more about the nature of their product families and how they impact platform-based product development. We assert that the development of a product platform and its derivative family of products is also impacted by the homogenous/heterogeneous nature of the products being developed, which has received little attention in the engineering literature. The current study introduces an original metric for assessing the homogeneity/heterogeneity in a given family: the Homogeneity versus Heterogeneity Ratio (HHR), which works at two levels of abstraction, namely, family and function. This study focuses on the platform leveraging strategy and takes an interest in two other aspects of platform development: the specification of the family and the necessary differentiation. To support platform design, the HHRfamily and HHRfunction metrics quantify the ratio of homogeneity/heterogeneity in the family to recommend a platform leveraging strategy by highlighting homogeneous functions that support platform leveraging. Reverse engineering helps us to retroactively study three types of families (power tools, single-use cameras, and blue jeans) using HHRfamily and HHRfunction. In particular, we demonstrate: (1) quantification of the homogeneity/heterogeneity of a family of products based on their functions; (2) recommendation of a leveraging strategy based on HHR; (3) a new leveraging strategy, the combined leveraging strategy via cross leveraging; (4) how HHR can help designers to validate the product family specification; and (5) how HHR can highlight needs to differentiate a family of products other than through functions.
Three Dimensional Design Structure Matrix With Cross-Module and Cross-Interface Analyses
Authors: Alizon Fabrice , Moon Seung Ki , Shooter Steven B. , Simpson Timothy W.
Published: May 2009

Many companies that struggle with product variety and configuration management issues turn to a module-based design approach. Although this approach is well-known to be efficient for managing variety of a product family, current methods do not enable designers to handle both modularity and variety within a product family. The Design Structure Matrix (DSM) has been widely used to identify modules within a product, but its use to identify modules across a family of products has been limited. In this context we propose two tools based on an extension of the basic DSM to manage variety of an entire product family. The Variety Design Structure Matrix, DSMV, handles variety of the product family and 3D Design Structure Matrix, DSM3D, enables visual analysis of across the entire product family. These two tools, combined into a single approach, enable analysis of the product family at many levels — family product, module, and interfaces — to better specify modules and interfaces across all of the products in the family. A case study involving a family of three single-use cameras is used to demonstrate the application of these new DSMs and accompanying cross-module and cross-interface analyses. This new approach can be applied during detailed studies as well as in the early stages of the design process.
The SPARKy (Spring Ankle With Regenerative Kinetics) Project: Design and Analysis of a Robotic Transtibial Prosthesis With Regenerative Kinetics
Authors: Hitt Joseph K. , Bellman Ryan , Holgate Matthew , Sugar Thomas G. , Hollander Kevin W.
Published: May 2009

Even today’s most sophisticated microprocessor controlled ankle-foot prosthetic devices are passive. They lack internal elements that actively generate power, which is required during the “push-off” phase of normal able-bodied walking gait. Consequently, lower limb amputees expend 20–30% more metabolic power to walk at the same speed as able-bodied individuals. Key challenges in the development of an active ankle-foot prosthetic device are the lack of high power and energy densities in current actuator technology. Human gait requires 250W of peak power and 36 Joules of energy per step (80kg subject at 0.8Hz walking rate). Even a highly efficient motor such as the RE75 by Maxon Precision Motors, Inc. rated for 250W continuous power with an appropriate gearbox would weigh 6.6 Kg. This paper presents the first phase of the Spring Ankle with Regenerative Kinetics (SPARKy 1), a multi-phased project funded by the US Army Military Amputee Research Program, which seeks to develop a new generation of powered prosthetic devices based on the Robotic Tendon actuator, that significantly minimizes the peak power requirement of an electric motor and total system energy requirement while providing the amputee enhanced ankle motion and “push-off” power. This paper will present data to show the kinetic advantages of the Robotic Tendon and the electro-mechanical design and analysis of SPARKy 1 that will provide its users with 100% of required “push-off” power and ankle sagittal plane range of motion comparable to able-bodied gait.
First-Order Coordination of the Articulated Arm Subassembly Using Curvature Theory
Authors: Ambike Satyajit , Schmiedeler James P.
Published: May 2009

This paper presents an approach to obtain the first-order speed ratios for three-degree-of-freedom spatial mechanisms that allow three degrees of translational freedom. The approach eliminates the need to locate the canonical frame and find the instantaneous invariants of motion and provides a direct method of obtaining the first-order speed ratios. The expressions for the speed ratios of the articulated arm subassembly are analyzed, and the regions of the workspace wherein the joints have dwells in their trajectories are identified. The first-order Taylor series is used for joint coordination, allowing the system to track a predefined spatial path. An example illustrating the application of curvature theory to spatial path tracking with a specific articulated arm subassembly is presented.
Dog Gait Analysis Using the Center of Pressure
Authors: Marghitu Dan B. , Steiss Janet , Banu Eliza , Light Victoria
Published: May 2009

In this study we evaluate the applicability of nonlinear mathematical techniques to describe and define normal dog gait. A commercially available walkway 2-dimensional motion analysis system was utilized to acquire kinematic data from healthy dogs. The kinematic data of the center of pressure (COP) of the dog during walking were analyzed. The ability to analyze COP on individual dogs has the potential to provide insight into normal and abnormal gait in dogs, and early detection of subtle lameness. This is especially important in working and athletic dogs.
Synthesis of Planar, Shape-Changing Rigid Body Mechanisms Approximating Closed Curves
Authors: Persinger Justin A. , Schmiedeler James P. , Murray Andrew P.
Published: May 2009

This paper presents a procedure to synthesize planar linkages, composed of rigid links and revolute joints, that are capable of approximating a shape change defined by a set of closed curves possessing similar arc lengths. The synthesis approach is more rigorous and more broadly applicable to dramatic changes between larger numbers of shapes than existing techniques that employ graphical methods. Link geometry is determined through an existing procedure, and those links are then joined together in a chain using numerical optimization to minimize the error in approximating the shape change. Binary links are added to this chain via a search of the design space such that actuated links can be driven monotonically to exact the shape change. The focus is single-degree-of-freedom (DOF) mechanisms that approximate closed curves, but the methodology is similarly applicable to generating mechanisms approximating sets of open curves and multi-DOF systems. The procedure is applied to synthesize an example mechanism that changes between circular, elliptical, and teardrop shapes as inspired by an aerodynamic flow field modification application.
Study on Vibration Attenuation Performance of a New Structural Electrorheological Fluid Damper
Authors: Liu Wangzhong , Chen Zhaobo , Li Mingzhang , Jiao Yinghou
Published: May 2009

A new structural ER (electrorheological) damper based on the characteristic of controllable force of electrorheological fluid (ERF) is proposed. The positive and negative electrodes of the damper consisted of series of concentric cylinders generate great damping forces. The damper works in a state of hybrid of shearing and flow mode. The damping force is generated when electric field is applied. The Bingham model are used to describe the ERF in the post-yielding regime, the theoretical expressions of damping force are developed based on numerical analysis of several ER dampers. A simple two degree of freedom vibration system is taken as an example to evaluate the vibration attenuation performance of the damper. The system is excited by sinusoidal force with certain frequency and the ER damper replaced the conventional damper. The simulation results of the response of displacement as well as acceleration are illustrated to show the effectiveness and feasibility of the damper in vibration control.
Combining Marketing and Engineering Tools for Multi-Attribute Optimization
Authors: Amarchinta Hemanth K. , Grandhi Ramana V.
Published: May 2009

Multidisciplinary design optimization has been an active topic of research in the past two decades in developing algorithms for reducing computational cost of re-analysis and also in developing efficient ways of calculating sensitivities. Most of the efforts were aimed at single objective function (attribute). Also very little work is done to include designer’s preferences inside the optimization. In this paper, conjoint analysis, a popular marketing technique to assess consumer preferences is used to involve the preferences of the designer. The optimization is driven by the designer’s preferences and a preferred design is obtained. Here, a novel way of combining tools from marketing and engineering is shown. A cantilever beam, and a composite lightweight torpedo are used as examples to demonstrate the method.
Pitting Load Capacity of Helical Gears
Authors: Ho¨hn Bernd-Robert , Oster Peter , Steinberger Gregor
Published: May 2009

In experimental analyzes the pitting load capacity of case carburized spur and helical gears is determined in back-to-back test rigs. The research program with one type of spur and 8 types of helical gears includes tests for the determination of influences of varying load distribution, overlap ratio and transmission ratio. The test results are presented and evaluated on the basis of the pitting load capacity calculation methods of ISO 6336-2/DIN 3990, part 2. A new DIN/ISO compatible calculation method for pitting load capacity is presented. This new calculation method comprehends helical gears more adequate than ISO 6336-2 / DIN 3990, part 2 and has the possibility to consider tooth flank modifications. The new calculation method is applied on test results and gears of a calculation study. It shows better accordance with the experimental test results than the present ISO 6336-2 / DIN 3990, part 2.
Bridging the Abstraction Gap for the Design of Embedded Reactive Systems Using Esterel: A Case Study
Authors: Zauner Martin , Kramer Michael , Balog Peter
Published: May 2009

New design methodologies at higher abstraction levels are necessary to deal with the increasing complexity of modern embedded systems. As a consequence, new design paradigms must supersede traditional design methods to bridge the abstraction gap which often exists between specification and implementation. This paper examines several examples which evaluate the applicability of Esterel, a language with well-defined semantics for specification and verification of reactive control systems. Implementation size, performance and design effort were selected as measures to assess the benefits of this design approach in comparison to a traditional one.
Experimental Study of Treating Volatile Organic Compounds
Authors: Amano Ryo S. , Martinez Lucci Jose , Guntur Krishna S. , Hossain M. Mahmun , Morshed M. Monzur , Dudley Matthew E. , Laib Franklin
Published: May 2009

Heated Soil Vapor Extraction (HSVE) is a technology that has been used successfully to clean up subsurface soils at sites containing chlorinated solvents and petroleum hydrocarbons. The costs have been extremely high due to the large amount of energy required to volatilize high molecular weight polycyclic aromatic hydrocarbon (PAH) compounds present in the soil matrix. One remediation contractor states that hydrocarbons are oxidized in situ by achieving temperatures in the >1000 F range near the heaters [1]. A critical question is whether the volatile portion of manufactured gas plant (MGP) hydrocarbons (VOCs) can be stripped out at lower temperatures such that the remaining contaminants will be unavailable for transport or subsequent dissolution into the groundwater. Soil remediation by heated soil vapor extraction system is a relatively new technology developed by Jay Jatkar Inc. (JJI) along with the University of Wisconsin-Milwaukee [2]. The areas around chemical companies or waste disposal sites have been seriously contaminated from the chemicals and other polluting materials that are disposed off. The process developed by JJI, consists of a heater/boiler that pump and circulates hot oil through a pipeline that is enclosed in a larger-diameter pipe. This extraction pipe is vertically installed within the contaminated soil up to a certain depth and is welded at the bottom and capped at the top. The number of heat source pipes and the extraction wells depends on the type of soil, the type of pollutants, moisture content of the soil and the size of the area to be cleaned. The heat source heats the soil, which is transported in the interior part of the soil by means of conduction and convection. This heating of soil results in vaporization of the gases, which are then driven out of the soil by the extraction well. The extraction well consists of the blower which would suck the vaporized gases out of the system. Our previous studies had removed higher boiling compounds, such as naphthalene, etc., to a non-detectable level. Thus, the current technology is very promising for removing most of the chemical compounds; and can also remove these boiling compounds from the saturated zone. Gas chromatography (GC) is utilized in monitoring the relative concentration changes over the extraction period. Gas chromatography-mass spectrometry (GC-MS) assists in the identification and separation of extracted components. The experimental research is currently being conducted at the University of Wisconsin-Milwaukee. The objectives of this study are to identify contaminants and time required to remove them through HSVE treatment and provide data for computation fluid dynamics CFD analysis.
General Mobility Identification and Rectification of Watt Six-Bar Linkages
Authors: Ting Kwun-Lon , Xue Changyu , Wang Jun , Currie Kenneth R.
Published: May 2009

Mobility identification is a common problem encountered in linkage analysis and synthesis. Mobility of linkages refers to the problems concerning branch defect, full rotatability, singularities, and order of motion. By introducing the concept of stretch rotation, the paper shows the existence of a hidden five-bar loop in a Watt six-bar linkage and how it affects the formation of branches, sub-branches, as well as the whole mobility of the entire linkage. The paper presents the first methodology for a fully automated computer-aided complete mobility analysis of Watt six-bar linkages.
Computer Integrated Design of Surfboard-Fins to Improve Turning Ability With Drag Force Reduction
Authors: Sakamoto Haruo , Yanamoto Yukari
Published: May 2009

This paper describes the design and development of surfboard-fins as products for marine sports. The purpose of the research is to improve turning ability by reducing drag force on the fins. Design modification was conducted, based on conventional fins, to increase turning ability and lower drag force. Three modified center-fins and three modified side-fins were selected. The design process involved 3D-CAD fin configuration models created with ProENGINEER Wildfire and utilized computational fluid dynamics from 3D-CAD data. Solid forms, which are required in this study since fin configuration is streamlined, are difficult to use in 3D-CAD software. Therefore, a surface element software (NURBS) developed by a propeller maker in Japan was used and the fins were converted into solid forms. After producing the fin models, the performance of factors such as turning ability and drag force were calculated using computational fluid dynamics. A flow experiment was conducted using a flow water tank in Western Hiroshima Prefecture Industrial Research Institute. This report commences with an explanation of the modifications on the fin models to improve turning ability and lower the drag force. It is then followed by the flow analysis using computational fluid dynamics software and the flow experimental results.
A Graph Grammar Approach to Generate Neural Network Topologies
Authors: Vempati Chaitanya , Campbell Matthew I.
Published: May 2009

Neural networks are increasingly becoming a useful and popular choice for process modeling. The success of neural networks in effectively modeling a certain problem depends on the topology of the neural network. Generating topologies manually relies on previous neural network experience and is tedious and difficult. Hence there is a rising need for a method that generates neural network topologies for different problems automatically. Current methods such as growing, pruning and using genetic algorithms for this task are very complicated and do not explore all the possible topologies. This paper presents a novel method of automatically generating neural networks using a graph grammar. The approach involves representing the neural network as a graph and defining graph transformation rules to generate the topologies. The approach is simple, efficient and has the ability to create topologies of varying complexity. Two example problems are presented to demonstrate the power of our approach.
Exact Response of a Translating String With Arbitrarily Varying Length Under General Excitation
Authors: Zhu W. D. , Zheng N. A.
Published: May 2009

The exact response of a translating string with constant tension and arbitrarily varying length is determined under general initial conditions and external excitation. The governing equation is transformed to a standard hyperbolic equation using characteristic transformation. The domain of interest for the transformed equation is divided into groups of sub-domains according to the properties of wave propagation. The d’Alembert’s solution for any point in the zeroth sub-domain group is obtained by using the initial conditions. The solution is extended to the whole domain of interest by using the boundary conditions, and a recursive mapping is found for the solution in the second and higher groups of sub-domains. The least upper bound of the displacement of the freely vibrating string is obtained for an arbitrary movement profile. The forced response of the string with non-homogeneous boundary conditions is obtained using a transformation method and the direct wave method. A new method is used to derive the rate of change of the vibratory energy of the translating string from the system viewpoint. Three different approaches are used to derive and interpret the rate of change of the vibratory energy of the string within the control volume, and the energy growth mechanism of the string during retraction is elucidated. The solution methods are applied to a moving elevator cable with variable length. An interesting parametric instability phenomenon in a translating string with sinusoidally varying length is discovered.
Robust Product Design Optimization Method Using Hierarchical Representations of Characteristics
Authors: Yoshimura Masataka , Sasaki Koichi , Izui Kazuhiro , Nishiwaki Shinji
Published: May 2009

Product design optimizations usually require the optimization of not only all performance characteristics, but also the robustness of certain performance characteristics. Obtaining optimum design solutions is far from easy, since this requires evaluations of numerous related characteristics that usually have complicated and conflicting interrelationships. Some of these characteristics can include variations of one type or another, such as manufacturing process variations, variations pertaining to the environments where the product is used, variations in how long-term use affects certain product characteristics, and so on. The difficulty of obtaining optimum design solutions is thus compounded by the need to carry out specific optimizations that provide sufficient robustness to safely accommodate anticipated ranges of variations. This paper expands the hierarchical multiobjective optimization method based on simplification and decomposition of characteristics so that optimizations can be concurrently conducted for both performance characteristics and maximization of robustness against characteristic variances. A principal cause of variations in performance characteristics is variations in the contact conditions of joints, and the utility of the proposed robust product design optimization method is demonstrated by applying it to machine-tool models that include joints.