bluuebunny/crossref_metadata_2025 huggingface dataset:
Investigation on Effects of the Sleeper Defects on Rail Vehicle Vibration
Authors: Mortezaee Hosein , Jalili Mohammad Mahdi , Ahmadian Mohamad Taghi
Published: September 2013

In this article effects of sleepers defect on rail vehicle vibration have been investigated. Two parallel rails of the track have been modeled as Euler-Bernoulli beams on elastic points as rail pads. Also sleepers have been modeled as visco-elastic Euler-Bernoulli beams. It is assumed that, some sleepers under the rail track have been fractured and modeled by two beams. The wheelset has 5 DOF which are longitudinal, vertical and lateral movements plus roll and axial rotations. To determine normal contact force between wheel and rail, relative position of wheel and rail has been determined at each instant. Using the coordinate of each wheel points in rail coordinate system, the penetration of wheel in rail has been determined. To determine rail-wheel contact forces, Hertzian nonlinear contact theory and Kalker theory have been used. A computer program has been developed that numerically solves the equations of motion of the train for different operating conditions using Runge Kutta Cash-Karp computation method. Using this model the effects of train velocity, wagon weight, number of fractured sleepers and fracture location on rail vehicle vibration have been investigated.
Functional-Based Search for Patent Technology Transfer
Authors: Russo Davide , Montecchi Tiziano , Liu Ying
Published: September 2013

Patent literature contains over 70 million patent documents, so the amount of information available to companies and the opportunity to derive business value and market new products from this collection is huge. However, presently an effective information extraction is a difficult task because patentees typically write using their own lexicon, style and strategy in describing their inventions.

This paper presents a discussion about open problems and a way to overcome them by a new functional search based on Function-Behaviour-Physical effect-Structure ontology. This ontology is used for a technology transfer activity by patents, with the aim of making users aware of how technologies, not yet exploited in their own field, have already been patented in other domains and exactly for achieving their same desired goal. To reach this objective a multidisciplinary approach is proposed, combining design ontologies with information retrieval tools. A case study has been presented to demonstrate how the conceived framework is strategic to search for patents and automatically classify them according to the proposed ontology.
LCA Estimation of End-Milling Condition Derived From Catalog-Mining Considering Human Learning Curve
Authors: Kodama Hiroyuki , Hirogaki Toshiki , Aoyama Eiichi , Ogawa Keiji , Sakamoto Junichi
Published: September 2013

Choosing cutting tools and end-milling conditions depends on expert engineers’ knowledge and experience, and often a lengthy process of trial and error is required before they obtain appropriate cutting conditions. We have previously proposed data-mining methods to make decisions about end-milling conditions on the basis of catalog data. We cut hardened die steel JIS SKD61 under three kinds of end-milling conditions: catalog recommended conditions, conditions derived from data-mining (mined conditions), and expert engineer conditions. We used LCA to evaluate quantitatively the environmental impact resulting from these conditions. We designed an index model of the environmental burden in the technical mastering process under the three condition. The results show that unskilled engineers could decrease the cumulative environmental burden by working under the mined condition in the initial stage. Recommending the use of the mined condition in the initial stage is therefore considered best.
Style Design System Based on Class A Bézier Curves for High-Quality Aesthetic Shapes
Authors: Oya Tetsuo , Kimura Fumihiko , Aoyama Hideki
Published: September 2013

In this paper, a style design system in which the conditions for Class A Bézier curves are applied is presented to embody designer’s intention by aesthetically high-quality shapes. Here, the term “Class A” means a high-quality shape that has monotone curvature and torsion, and the recent industrial design requires not only aesthetically pleasing aspect but also such high-quality shapes. Conventional design tools such as normal Bézier curves can represent any shapes in a modeling system; however, the system only provides a modeling framework, it does not necessarily guarantee high-quality shapes. Actually, designers do a cumbersome manipulation of many control points during the styling process to represent outline curves and feature curves; this hardship prevents designers from doing efficient and creative styling activities. Therefore, we developed a style design system to support a designer’s task by utilizing the Class A conditions of Bézier curves with monotone curvature and torsion.
Alternate Mistuning of Turbine Bladings Coupled by Underplatform Dampers
Authors: Tatzko S. , Panning-von Scheidt L. , Wallaschek J. , Kayser A.
Published: September 2013

In turbo machinery design it is important to avoid vibrations that can destroy the turbine in the last resort. The rotating structure is exposed to periodic excitation forces. Two main types of periodic excitation can be distinguished. Flutter is the effect when mass flow forces couple with a natural vibration mode. The result is a negative damping coefficient and amplitudes will rise up to malfunction of the structure. The engine order excitation is a periodic excitation where the force signal is directly related to the speed of the rotor. A forced response calculation gives information about the blade vibration. Nonlinear coupling, i.e. friction coupling, between blades is used to increase damping of the bladed disk. Dynamic analysis of turbine blades with nonlinear coupling is a complex task and computer simulations are inevitable. Various techniques have been developed to reduce computational effort. The cyclic symmetry approach assumes each blade around the disk to be identical. Thus only one sector of the disk is sufficient to compute the steady state solution of the whole turbine blading. However, it has been observed that mistuning of blades reduces the flutter instability. On the other hand statistical mistuning can lead to dangerously high forced response amplitudes due to mode localization. A compromise is intentional mistuning. The simplest approach is alternate mistuning with every other blade exhibiting identical mechanical properties. This work explains in detail how a turbine bladed disk can be modeled when alternate mistuning is applied intentionally. Cyclic symmetry is used and each sector comprises two blades. This untypical choice of the sector size has significant impact on results of a cyclic modal analysis. Simulation results show the influence of alternate mistuned turbine bladings which are coupled by underplatform damper elements.
Somatic/Embodied Knowledge Representation: A Challenge
Authors: Fukuda Shuichi
Published: September 2013

Recent brain studies revealed brain and body cannot be separated. Further it revealed blood and muscles play an important role in our information processing. Bike riding is known as a typical example of tacit knowledge. Although there are efforts on how we can change such tacit or somatic/embodied knowledge of ours as this example into explicit one, we have been not so successful. From our past two series of experiments about detection of emotion from face and about calligraphy, we learned acceleration plays a crucial role. This paper attempts to represent somatic/knowledge representation as patterns of position and acceleration. This is still a preliminary study but it may lead us to another way of representing our tacit knowledge and thus we may develop another way of transferring tacit knowledge such as skills, bike riding, etc in the form of patterns of position and acceleration. Mechanical engineering is a tangible engineering. Therefore the author would like to emphasize the importance of exploring how we can represent our somatic/embodied knowledge. This is a very much preliminary step toward that goal.
Applying Rigidity Theory Methods for Topological Decomposition and Synthesis of Gear Train Systems
Authors: Terushkin Maria , Shai Offer
Published: September 2013

This paper introduces a novel way to augment the knowledge and methods of rigidity theory to the topological decomposition and synthesis of gear train systems. A graph of gear trains, widely reported in the literature of machine theory, is treated as a graph representation from rigidity theory—the Body-Bar graph. Once we have this Body-Bar graph, methods and theorems from rigidity theory can be employed for analysis and synthesis. In this paper we employ the pebble-game algorithm, a computational method which allows determination of the topological mobility of mechanisms and the decomposition of gear trains into basic building blocks—Body-Bar Assur Graphs. Once we gain the ability to decompose any gear train into standalone components (Body-Bar Assur Graphs), this paper suggests inverting the process and applying the same method for synthesis. Relying on rigidity theory operations (Body-Bar extension, in this case), it is possible to construct all of the Body-Bar Assur Graphs, meaning the building blocks of gear trains. Once we have these building blocks at hand, it is possible to recombine them in various ways, providing us with a topological synthesis method for constructing gear trains. This paper also introduces a transformation between the Body-Bar graph and other graph representations used in mechanisms, thus leaving room for the application of the proposed synthesis and decomposition method directly to known graph representations already used in machine theory.
Module Definition for Product-Service Systems
Authors: Hölttä-Otto Katja , Tang Victor , Otto Kevin
Published: September 2013

More and more manufacturing firms are transitioning to more serviced based offerings. It has been shown that a useful integrated bundle of services through a complimentary product can be a better business model than just adding support services to a product as tactical responses to customer needs. In order for companies to be able to define these integrated bundles in an efficient and systematic manner, a process is needed. In the paper we propose a new method to define modular services, ones that can be leveraged efficiently as driving entities, and which can be provided using several product offers. The service modules consist of services modularized for leveraging across several products. The method builds upon the foundations in product platform and modularity research extending it to product service systems. Further, we introduce alternative service modular platform leveraging strategies.
Shock-Induced Electrostatic Coupling of Modes of Vibration in the Response of a MEMS Ring Sensor
Authors: Sieberer Stefan , Popov Atanas A. , McWilliam Stewart
Published: September 2013

This paper is concerned with non-linear coupling of in-plane rigid-body and flexural motion in capacitive MEMS ring sensors due to shock excitation. A Lagrangian approach is used to derive the equations of motion for the system, including non-linear electrostatic forces. The shock acceleration is modelled as a half-sine wave input and acts on the rigid-body motion only. The mechanism of modal coupling is derived theoretically, and numerical simulations are performed to quantify the coupling. Different electrode configurations are considered by including electrostatic plates both inside and outside the ring, and insights into modal coupling are gained.
A Compliance-Based Compensation Approach for Designing High-Precision Flexure Mechanism
Authors: Li S. Z. , Yu J. J. , Zong G. H. , Su Hai-jun
Published: September 2013

This paper presents an approach of utilizing parasitic motion compensation for designing high-precision flexure mechanism. This approach is expected to improve the accuracy of flexure mechanism without changing its degree of freedom (DOF) characteristic. Different from the method which mainly concentrates on how to compensate the parasitic translation error of a parallelogram-type flexure mechanism existing in most of the literatures, the proposed approach can compensate the parasitic motion produced by rotation in company with translation. Besides, the parasitic motion of a flexure mechanism is formulated and evaluated by utilizing its compliance. To specify it, the compliance of a general flexure mechanism is calculated firstly. Then the parasitic motions introduced by both rotation and translation are analyzed by utilizing the resultant compliance. Subsequently, a compliance-based compensation approach is addressed as the most important part of this paper. The design principles and procedure are further proposed in detail to help with improving the accuracy of the flexure mechanism. Finally, a case study of a 2R1T flexure mechanism is provided to illustrate this approach, and FEA simulation is implemented to demonstrate its validity. The result shows that it is a robust design method for the design of high-precision flexure mechanism.
Manufacturability and Viability of Different C-Gear Types: A Comparative Study
Authors: Arafa Hani A. , Bedewy Mostafa
Published: September 2013

The family of cylindrical parallel-axis involute gearing currently include spur, helical and double-helical gears, all having straight tooth traces in the developed pitch plane. However, gears with curved tooth traces have also been proposed. One of the obvious merits of this configuration is the insensitivity to shaft misalignment. Although this and other merits of gears with lengthwise curved teeth (C-gears) were highlighted, they have never been mass-manufactured. Many types and shapes of C-gears have been envisioned, a dozen or so, but the particular merits and demerits of each type were never put together in a comparative study aiming at stipulating which type of gear can be manufactured simplest of all or which type is most appropriate for use in specific applications. In this paper, a comprehensive comparative study is carried out for all C-gear types in the repertoire. Finally, the promising ones are singled out for detailed scrutiny; and prospective applications are pointed out for these types.
Towards Static Contact Multiphysics of Rough Surfaces
Authors: Michopoulos John G. , Iliopoulos Athanasios , Young Marcus
Published: September 2013

This paper is describing the current status of ongoing work on developing a comprehensive modeling and simulation infrastructure capable of addressing the multiphysics behavior aspects of rough surfaces in contact. The electrical and thermal response of bodies in contact under the influence of mechanical load electric currents and thermal fluxes, is a topic of interest for many application areas. We are presenting a multiscale theory leading to derivations of expressions of electric and thermal conductivities for the case of static contact. The associated model contains both an asperity based comprehensive model as well as its continuum level coupling. The mechanical pressure and the repulsion effect from electric current through the micro-contacts as well as temperature and strain rate dependence of the plastic behavior of the asperity are accounted for as well. This formalism enables the derivation of physical properties from surface topography and bulk material properties for the interface between two rough surfaces in contact. Numerical analysis results present the dependence of the derived properties from the surface characteristics applied external load and the electric current.
Design and Prototyping of a Walking Quadrotor
Authors: Kalantari Arash , Spenko Matthew
Published: September 2013

The design and experimental prototype of a hybrid robot capable of both aerial and terrestrial locomotion is presented in this paper. A unique compliant mechanism design makes it possible to use a single actuator set for both walking and flying. This is advantageous because it reduces both the total weight of the system and the control system complexity. The basic structure is similar to a quadrotor aerial vehicle, i.e. four brushless DC motors provide the required thrust for flying. The desired leg motion is derived from two separate linear movements. Horizontal motion of the legs is achieved by driving the main actuators in reverse. A second linear actuation unit, which is set into motion by shape memory alloy (SMA) wires, enables vertical movement of the leg during terrestrial locomotion.
Using Model-Based Design in Engineering Design Education
Authors: Andersson Kjell
Published: September 2013

Project-based education in combination with problem-based learning has been one of the key factors for the popularity of engineering design education among students at technical universities. The use of industry-connected projects has boosted this popularity still further. To get feedback from professionals in industry is very stimulating and in this way students also get confirmation that their education is related to industrial needs.

In the Machine Design capstone course at KTH Department of Machine Design, the curriculum covers the whole process from idea generation to manufacturing and testing a final prototype. A major part of the course consists of project work where students will develop a product prototype in close cooperation with an industrial partner or with a research project at the department. The benefits of using real prototypes cannot be stressed enough. This is a very efficient way to explain to the students why a product must be designed in a certain way, e.g. to make it possible to assemble.

This means that a major part of the course is using project-based learning as a teaching strategy. In addition, the use of model-based design is introduced as a methodology that enables the students to evaluate and “experience” many different behaviors of the product using digital models in a virtual environment. In this way many undesirable concepts and flaws can be avoided even before a prototype is manufactured.

This paper describes a model-based methodology for product development. It also shows the application of this methodology in project work in a capstone course in engineering design at KTH, and discusses the effects on student motivation and learning.
On Utilizing Approximate Modal Shapes to Estimate the Effective Nonlinearity of a Structural Mode
Authors: Silva Clodoaldo J. , Daqaq Mohammed F.
Published: September 2013

This effort investigates the accuracy of estimating the effective nonlinearity of a given vibration mode using approximate modal shapes. As an example, the problem of approximating the modal effective nonlinearities of a linearly-tapered cantilever beam (along the width) is considered. This example was intentionally selected because the linear eigenvalue problem cannot be solved analytically for the exact eigenfrequencies and actual linear mode shapes of the structure, which permits investigating the influence of approximating the mode shapes on the effective nonlinearity. The nonlinear partial differential equation governing the beam’s motion is first discretized into an infinite set of nonlinear ordinary differential equations. The method of multiple scales is then utilized to obtain an approximate analytical expression for the effective nonlinearity which depends on the assumed mode shapes used in the series discretization. To approximate the mode shapes, three methods were utilized: i) a crude approach which directly utilizes the linear modes of a regular (untapered) cantilever beam to estimate the effective nonlinearity, ii) a finite element approach wherein the structural modes are obtained in ANSYS, then fitted into orthonormal polynomial curves while minimizing the least square error in calculating the eigenfrequencies, and iii) a Rayleigh-Ritz approach which utilizes a set of orthonormal trial basis functions to construct the structural mode shapes as a linear combination of the trial functions used. A comparison among the three methods for eight different taperings reveals that, while the modal frequencies are well-approximated yielding less than 2% deviation among the three methods, there is a huge discrepancy in approximating the nonlinear coefficients including the effective nonlinearity. This leads to the conclusion that convergence of the eigenfrequencies is not sufficient for accurate estimation of the nonlinear parameters.
Current Drivers and Obstacles of Synergy in Cyber-Physical Systems Design
Authors: Gerritsen Bart H. M. , Horváth Imre
Published: September 2013

The level of synergy is a quality measure of the cooperative actions of the components of cyber physical systems (CPSs). Our current research informed us that the phenomenon of synergy has not been understood sufficiently yet, and that there are many, even competing, views on how to interpret and operationalize it in CPSs. We can talk about synergy when the functionally and geographically distributed dissimilar system components work in concert together and create a system behavior/performance that is of higher value than the total of the individual components is. Towards synergy, unification and interoperation principles need to be considered both in design and in implementation of CPSs. In this paper, we elaborate on the various aspects of synergy, and critically analyze its drivers and obstacles. Our analysis extended to ontological, epistemological, methodological, manifestation and operational aspects of synergy. It has been found that emergence of truly synergic technologies, proliferation of sophisticated abstraction models, model-driven system specification, and platform-based function realization are the most important drivers of synergy. On the other hand, the different mental models and vocabularies, the lack of multi-level informatics, the limitations in handling non-hierarchical complexities, managing emergent intelligence and autonomous operation, and the premature state of informing science have been identified as the major obstacles. The paper makes a proposal for enhanced synergy by taking the advantage of the affordances and reducing the effects of the obstacles. The results of the critical analysis are design principles that can be used to increase the level of synergy of CPSs.
Approximation Assisted Multiobjective Optimization With Combined Global and Local Metamodeling
Authors: Hu W. , Saleh K. H. , Azarm S.
Published: September 2013

Approximation Assisted Optimization (AAO) is widely used in engineering design problems to replace computationally intensive simulations with metamodeling. Traditional AAO approaches employ global metamodeling for exploring an entire design space. Recent research works in AAO report on using local metamodeling to focus on promising regions of the design space. However, very limited works have been reported that combine local and global metamodeling within AAO. In this paper, a new approximation assisted multiobjective optimization approach is developed. In the proposed approach, both global and local metamodels for objective and constraint functions are used. The approach starts with global metamodels for objective and constraint functions and using them it selects the most promising points from a large number of randomly generated points. These selected points are then “observed”, which means their actual objective/constraint function values are computed. Based on these values, the “best” points are grouped in multiple clustered regions in the design space and then local metamodels of objective/constraint functions are constructed in each region. All observed points are also used to iteratively update the metamodels. In this way, the predictive capabilities of the metamodels are progressively improved as the optimizer approaches the Pareto optimum frontier. An advantage of the proposed approach is that the most promising points are observed and that there is no need to verify the final solutions separately. Several numerical examples are used to compare the proposed approach with previous approaches in the literature. Additionally, the proposed approach is applied to a CFD-based engineering design example. It is found that the proposed approach is able to estimate Pareto optimum points reasonably well while significantly reducing the number of function evaluations.
Consider-Then-Choose Models in Decision-Based Design Optimization
Authors: Morrow W. Ross , Long Minhua , MacDonald Erin F.
Published: September 2013

This article describes an advance in design optimization that includes consumer purchasing decisions. Decision-Based Design optimization commonly relies on Discrete Choice Analysis (DCA) to forecast sales and revenues for different product variants. Conventional DCA, which represents consumer choice as a compensatory process through maximization of a smooth utility function, has proven to be reasonably accurate at predicting choice and interfaces easily with engineering models. However the marketing literature has documented significant improvement in modeling choice with the use of models that incorporate non-compensatory (descriptive) and compensatory (predictive) components. The non-compensatory component can, for example, model a “consider-then-choose” process in which potential customers first narrow their decisions to a small set of products using heuristic screening rules and then employ a compensatory evaluation to select from this set. This article demonstrates that ignoring consider-then-choose behavior can lead to sub-optimal designs, and that optimality cannot be “recovered” by changing marketing variables alone. A new computational approach is proposed for solving optimal design problems with consider-then-choose models whose screening rules are based on conjunctive (logical “and”) rules. Computational results are provided using three state-of-the-art commercial solvers (matlab, KNITRO, and SNOPT).
Comparing the Design Cognition of Two Engineering Majors: A Measurement-Based Approach
Authors: Lee Yoon Suk , Gero John , Williams Christopher B.
Published: September 2013

This paper presents the results of two years of a three-year longitudinal study on the impact of design education on students’ design thinking and practice. Two engineering majors in a large research-intensive state university are being studied. The control group is a major focused on engineering mechanics. The experimental group is a mechanical engineering major that uses design as a context for its curriculum. A task-independent protocol analysis method grounded in the Function-Behavior-Structure design ontology is utilized to provide a common basis for comparing students across discipline and year. This study reports data collected at the beginning and at the end of students’ sophomore year, and at the end of their junior year. Students in the experimental group completed an introductory mechanical design course, while students in the control group had no formal design component in their curriculum. The results of analyzing and comparing the percent occurrences of design processes and problem-solution index from the protocol analysis of both cohorts are presented. These results provide an opportunity to investigate and understand how students’ design cognition is affected by a design course.
Assembly Sequence Planning by Using Multiple Random Trees Based Motion Planning
Authors: Morato Carlos , Kaipa Krishnanand , Gupta Satyandra K.
Published: September 2013

In this paper, we introduce multiple random trees based motion planning to perform assembly sequence planning for complex assemblies. Initially, given an assembly model, our technique performs disassembly sequence planning. This approach dynamically reduces the size and complexity of the assembly based on a hierarchical exploration structure that keeps information about the completion of the disassembly. Next, the disassembly information is used to generate feasible assembly sequences, along with precedence constraints, to assemble each part into the current subassembly. The motion planning system chooses part order by detecting geometrical interferences and analyzing feasible part movements. Results from tests on a variety of complex assemblies validate the efficiency of our approach.
Affordances and Environmentally Significant Behavior
Authors: Srivastava Jayesh , Shu L. H.
Published: September 2013

In this paper, we apply design-by-affordance methodology to the problem of environmentally significant behavior. Affordances, as originally formulated, represent opportunities for action offered by a product. Subsequent work explored the use of affordances, defined as context-dependent relations between artifacts and users, in lieu of functions as a basis for design. While others have also developed detailed deductive methods of discovering affordances in products, we present affordance listing as an expedient technique for inductively discovering relevant affordances. We also present affordance transfer, a method for redesigning products to encourage environmentally significant behavior. We conclude by discussing insights gained from applying our two approaches.
Coordination of Product Design Process in View of Product and Organizational Structures
Authors: Oizumi Kazuya , Aoyama Kazuhiro
Published: September 2013

Management of product design projects becomes increasingly difficult as the complexity of products increases. For better management of such projects, well-considered preliminary coordination of design processes is essential. This paper proposes a method for coordination in the design process, which comprises two phases: 1) division of the design work into smaller tasks and sequencing them and 2) establishment of management activities. To facilitate this coordination, an integrated model of a product, process, and organization is proposed.

The division and sequencing of design tasks is based upon analysis of the product model. The method utilizes rational prioritization of design parameters, which means identification of parameters that must be first considered for changes.

The resulting design processes can show where coordination among design tasks is needed. This, in turn, implies the necessity of management. It is preferable for a different style of management to be adopted for each part. Here, the importance of management and organizational structure prescribe the style of management that should be adopted. In this paper, two approaches to management are discussed: 1) the formation of a pre-agreement, and 2) integration and after-approval.

Throughout the paper, the example of a solar boat design is used to explain how the proposed method works and to demonstrate its feasibility.
ACTIVE-Hand: Automatic Configurable Tactile Interaction in Virtual Environment
Authors: Wu You , Schmidt Lara , Parker Matthew , Strong John , Bruns Michael , Ramani Viniyak Karthik
Published: September 2013

We present a novel, low-power and untethered pneumatic haptic device, namely the ACTIVE-Hand, for realistic and real-time 3D gaming experience. Currently, body-motion based 3D gaming systems primarily use visual feedback to provide partly immersive gaming experiences. Tactile feedback systems in Virtual Reality provide immersion with high tactile resolution, but they are expensive and difficult to setup and calibrate. The conceptually economical modular design of the ACTIVE-Hand allows easily configurable tactile feedback as per application requirements. Contrary to commercial systems like Wii™ which provide global vibrations as a proxy for synthetic tactile feed-back, the ACTIVE Hand is comparably lightweight, yet scalable to meet localized tactile resolution requirements. The ACTIVE-Hand provides controllable pulses for dynamic virtual interactions such as pressing virtual buttons and hitting moving virtual balls. We successfully demonstrate the paradigm of dynamic tactile interactions in virtual environments through a 3D Pong game by integrating the ACTIVE-Hand with Kinect™ camera.
Representation: Structural Complexity of Assemblies to Create Neural Network Based Assembly Time Estimation Models
Authors: Miller Michael G. , Mathieson James L. , Summers Joshua D. , Mocko Gregory M.
Published: September 2013

Assembly time estimation is traditionally a time intensive manual process requiring detailed geometric and process information to be available to a human designer. As a result of these factors, assembly time estimation is rarely applied during early design iterations. This paper explores the possibility that the assembly time estimation process can be automated while reducing the level of design detail required. The approach presented here trains artificial neural networks (ANNs) to estimate the assembly times of vehicle sub-assemblies at various stages using properties of the connectivity graph at that point as input data. Effectiveness of estimation is evaluated based on the distribution of estimates provided by a population of ANNs trained on the same input data using varying initial conditions. Results suggest that the method presented here can complete the time estimation of an assembly process with +/− 15% error given an initial sample of manually estimated times for the given sub-assembly.
Criteria and Motion Generation for Multi-Segmental Legged Balancing
Authors: Joo Chang B. , Kim Joo H.
Published: September 2013

This paper investigates the effect of upper body on balancing by comparing balanced state domain in the phase space. Biped mechanism is simplified to multi-segment model which consists of one stance foot, leg, and upper body in sagittal plane. System parameters such as link mass and link length are chosen appropriately based on human anthropometry data. In addition to the system parameters, the necessary and sufficient conditions for balancing are implemented as constraints. Proposed algorithm iteratively solves nonlinear constrained optimization problem to find velocity extrema for a given set of joint variables and a maximum actuation torque. The balanced state domain of an actively controlled swinging arm demonstrates larger domain compared to the domain without swinging arm. While similar results are shown by other various approaches, the proposed algorithm demonstrates identification of the balanced state domain in a deterministic scheme using numerical optimization.
Optimization of Electrostatic Adhesives for Robotic Climbing and Manipulation
Authors: Ruffatto Donald , Shah Jainam , Spenko Matthew
Published: September 2013

This paper investigates the optimization of electrode geometry in electrostatic adhesives to enhance adhesion forces for use in robotic climbing and gripping applications. Electrostatic adhesion provides an attachment mechanism that is both controllable and effective over a wide range of surfaces including conductive, semi-conductive, and insulating materials. The adhesives function by utilizing a set of high voltage electrodes that generate an electric field. This electric field polarizes the substrate material, thus generating an adhesion force. Optimizing the geometry of these conductive electrodes provides enhanced adhesion forces that increase attachment robustness. To accomplish this, FEA software was used to evaluate the generated electric field for a given electrode configuration. A range of electrode widths and gap sizes were evaluated to find the optimal configuration. These findings were compared with experimental results for different pad geometries over a range of surface types. Experimental results indicate that on smooth surfaces the simulation results are representative of the actual recorded adhesion forces. Rough surfaces provide similar trends but with varying optimal configurations, likely due to the level of electric field dispersion.
Analysis of a Fixed-Guided Compliant Beam With an Inflection Point Using the Pseudo-Rigid-Body Model (PRBM) Concept
Authors: Midha Ashok , Bapat Sushrut G. , Mavanthoor Adarsh , Chinta Vivekananda
Published: September 2013

This paper provides an efficient method of analysis for a fixed-guided compliant beam with an inflection point, subjected to beam end load or displacement boundary conditions, or a combination thereof. To enable this, such a beam is modeled as a pair of well-established pseudo-rigid-body models (PRBMs) for fixed-free compliant beam segments. The analysis procedure relies on the properties of inflection in developing the necessary set of static equilibrium equations for solution. The paper further discusses the multiplicity of possible solutions, including displacement configurations, for any two specified beam end boundary conditions, depending on the locations of the effecting force and/or displacement boundary conditions. A unique solution may exist when a third beam end boundary condition is specified; however, this selection is not unconditional. A deflection domain concept is proposed to assist with the selection of the third boundary condition in a more realistic manner.
Advances in Transformational Design: Correlating Context Evaluation to Quality Feasibility and Novelty
Authors: Camburn Bradley , Wood Kristin , Crawford Richard , Robbens Jeremy , Jensen Dan , Patel Aadit
Published: September 2013

In response to the call for multi-functional products, we have developed several relevant ideation techniques. These techniques are tailored for design of transformers — devices with multiple functional states. In this paper, we present significant advancements in transformational design. Primarily, we introduce a method to enhance quality, novelty, and feasibility (QNF) of design solutions. The method is used to classify design problem context and suggest pursuit of one of the two following device archetypes, transformer or monomorph — devices with a single functional state. The Indicators method is associated with a significantly increased probability of producing a design problem solution with higher QNF than a control (standard) design method. The claim that this method is accurate, its results are repeatable, and usage thereof enhances QNF is supported by a network of experiments and analyses. Statistical analysis is used to establish the accuracy, precision and repeatability of the method. Industry-standard qualitative methods, including inter-rater reliability analysis, demonstrate that usage of the Indicators method enhances design concept QNF. Concurrent minor analyses highlight the novelty of transformable designs; and some positive psychological effects of using the method. Additionally, the contextual (archetype) indicators have shown implicit promise as a core element for future research into ideation methods.
Profile Tolerance Allocation for Rapid Prototyping of Sculptured Surfaces in a Direct Slicing Process
Authors: Barari Ahmad
Published: September 2013

Layer-based manufactured parts and surfaces are inherently subject to stair case effect which can be quantified by cusp height. Cusp height of a layer is the maximum distance measured along a surface normal between the ideal surface and the produced layer. Although calculation of local cusp high is a simple task but estimating the overall deviation zone of the produced surface is a highly nonlinear and complicated problem. This paper presents a practical approach to predict the actual profile tolerances of the surfaces. This prediction is used to allocate profile tolerances for the rapid prototyping process. Also the methodology can be used to select the optimum uniform layer thicknesses that compromise between the number of layers and the desired accuracy of the final surfaces. The unified developed methodologies are capable to analyse complex surfaces and geometries. Variety of experiments is carried out to study the effectiveness and practicality of the presented methodology. The developed methodology can be employed efficiently during design of rapid prototyping parts.
Handy-Potter: Rapid 3D Shape Exploration Through Natural Hand Motions
Authors: Vinayak  , Murugappan Sundar , Piya Cecil , Ramani Karthik
Published: September 2013

We present the paradigm of natural and exploratory shape modeling by introducing novel 3D interactions for creating, modifying and manipulating 3D shapes using arms and hands. Though current design tools provide complex modeling functionalities, they remain non-intuitive and require significant training since they segregate 3D shapes into hierarchical 2D inputs, thus binding the user to stringent procedural steps and making modifications cumbersome. In addition the designer knows what to design when they go to CAD systems and the creative exploration in design is lost. We present a shape creation paradigm as an exploration of creative imagination and externalization of shapes, particularly in the early phases of design. We integrate the capability of humans to express 3D shapes via hand-arm motions with traditional sweep surface representation to demonstrate rapid exploration of a rich variety of fairly complex 3D shapes. We track the skeleton of users using the depth data provided by low-cost depth sensing camera (Kinect™). Our modeling tool is configurable to provide a variety of implicit constraints for shape symmetry and resolution based on the position, orientation and speed of the arms. Intuitive strategies for coarse and fine shape modifications are also proposed. We conclusively demonstrate the creation of a wide variety of product concepts and show an average modeling time of a only few seconds while retaining the intuitiveness of communicating the design intent.
Novel Geometrical Approach to Designing Flow Channels
Authors: Camburn Bradley , Wood Kristin , Crawford Richard , Jensen Dan
Published: September 2013

Many natural systems that transport heat, energy or fluid from a distributed volume to a single flow channel exhibit an analogous appearance to trees (examples include bronchial tubes, watersheds, lightening, and blood vessels). Several authors have proceeded with analytical methods to develop fractal or pseudo-fractal designs analogous to these natural instances. This implicates an implicit belief in some designers that there is an optimal attribute to this ‘tree-like’ appearance. A novel explanation for the appearance of these systems is presented in this paper. Natural systems follow the path of least resistance; or in other words, minimize transport effort. Effort is required to overcome all forms of friction (an unavoidable consequence of motion). Therefore effort minimization is analogous to transport distance (path length) minimization. Effort due to friction will be integrated over the total transport distance. Leveraging this observation a simple, geometric explanation for the emergent ‘tree-like’ architecture of many natural systems is now achievable. Note that this ‘tree’ effect occurs when most of the flow volume exhibits diffusion, with a small percentage of interdigitated high flow velocity channels. One notable application of our novel method, path length analysis, is the automated creation of cooling channel networks for heat generating micro-chips. As a demonstration, this path length analysis method was used to develop a significantly more efficient channel configuration (by 14%) than the state of the art for conductive microchip cooling. An extensive array of finite element models confirms the performance of this novel configuration.
A Functionally–Aware Product Schematic Clustering Algorithm
Authors: Quan Ning , Kim Harrison M.
Published: September 2013

The formation of modules is an important step in establishing a product’s architecture. This paper proposes a clustering algorithm that creates functionally cohesive and loosely coupled modules in a product’s architecture. The algorithm seeks to group together product elements to form functionally similar and loosely-coupled modules. The algorithm also has the advantage of not requiring any user-defined starting parameters that are necessary in some other clustering algorithms. The proposed algorithm is demonstrated on a laser printer and the results are compared to the results from an existing algorithm.
Casting and Milling Restrictions in Topology Optimization via Projection-Based Algorithms
Authors: Guest James K. , Zhu Mu
Published: September 2013

Projection-based algorithms are arising as a powerful tool for continuum topology optimization. They use independent design variables that are projected onto element space to create structure topology. The projection functions are designed so that geometric properties, such as the minimum length scale of features, are naturally achieved. They therefore offer an efficient means for imposing geometry-related design specifications and/or manufacturing constraints. This paper presents recent advances in projection-based algorithms, including topology optimization under manufacturing constraints related to milling and casting processes. The new advancements leverage the logic of recently proposed algorithms for Heaviside projection, including eliminating continuation methods on projection parameters and potential for using multiple design variables to achieve active projection of each phase used in design. The primary advantages of such an approach are that manufacturing restrictions are achieved naturally, without need for additional constraints, and that sensitivity calculations are efficient and straightforward. The primary drawback of the approach is that the so-called neighborhood maps require storage for efficient processing when using unstructured meshing.
Topography Optimization of Shell Structures Under Transient Loading: A Comparative Approach
Authors: Medina Juan Camilo , Tovar Andrés
Published: September 2013

Topography optimization is an innovative technique that can significantly improve the response of certain type of structures. The most challenging aspect of topography optimization is the sensitivity analysis. In this manuscript two methods to approximate the sensitivities for problems in topography optimization are introduced. The gradient is supplanted with either a stochastic approximation, or a physical approximation. Initially, an overview of the state-of-the-art in topography optimization is presented, and some key issues are explored. Subsequently, the technique is outlined, and the proposed methods are introduced. Furthermore, a numerical example in which a structure composed of shell elements is subject to a blast load is provided. This example is solved employing stochastic gradient approximation, and approximate gradient. They are compared to the widely used finite differences approximation. It is possible to observe that the proposed method significantly reduces the computational effort required to solve the problem, while considerably improving the objective function.