bluuebunny/crossref_metadata_2025 huggingface dataset:
Experimental Investigation of Tire Torsional Dynamics on the Performance of an Anti-Lock Braking System
Authors: Adcox John , Ayalew Beshah , Rhyne Tim , Cron Steve , Knauff Mike
Published: February 2014

The designs of commercial Anti-Lock Braking Systems often rely on assumptions of torsionally rigid tire-wheel assemblies. However, some recent tire/wheel technologies often involve lower torsional stiffnesses that cannot be captured well using these rigid wheel assumptions. This paper presents both simulation and experimental analysis of the interaction between a typical ABS controller and tire torsional dynamics. The simulation work includes a comprehensive model that incorporated sidewall flexibility, transient and hysteretic tread-ground friction effects, and the dominant dynamics of a hydraulic braking system. The experimental tests were conducted on a quarter-vehicle ABS test fixture built around a chassis dynamometer. Sensitivity studies are completed through changes in the tire/wheel properties such as wheel inertia, torsional stiffness and ABS controller properties such as the controller’s filter cutoff frequency applied to the wheel speed signals. The results showed strong interactions between the tire’s torsional natural frequency and the filter cutoff frequency of the controller.
Computing Geometric Transformations of Irregular Teeth Sets for Orthodontic Treatment
Authors: Seshagiri Naveen K. , Crawford Richard H.
Published: February 2014

This research evaluates the feasibility of assisting orthodontists to treat irregularities in teeth by computing the geometric transformations to move each tooth to its ideal position. The intent is to help orthodontists craft a precise and specific treatment plan for each patient. The inputs for finding the transformations are the patient’s teeth mold and dental arch templates. A 3D laser scanner is used to generate a point cloud data representation of the patient’s teeth mold. A commercial solid modeler is used to construct a non-uniform rational B-spline surface from this point cloud. Transformations are then computed by establishing a multiple scan registration, matching the axis of the patient’s teeth model and dental arch templates, and computation of initial and final positions of the teeth. The steps in the process and the algorithms developed were implemented in the scripting language of the solid modeler. Details of the algorithms are provided, and a case study is presented to demonstrate the process.
An Algebraic and Computational Strategy for Structure Decomposition of Variable Topology Mechanisms
Authors: Kuo Chin-Hsing , Chang Lung-Yu
Published: February 2014

Identifying all the functional topological structures embedded in a variable topology mechanism (VTM) is a leading step when analyzing the topological characteristics of the mechanism. Such an identification task is equivalent to the structure decomposition of the VTM. In this paper, we introduce a systematic approach, which is both algebraically and computationally manipulate-able, for the structure decomposition of VTMs. Based on a given source mechanism of a VTM, all its embedded functional topological structures can be identified through an algebraic computation via this method. For illustrating the presented approach, the decomposition of an automatic steel clamping and sawing mechanism is demonstrated.
Diagonal Flexoelectric Sensors and Sensitivity Analysis on Cylindrical Shells
Authors: Tzou H. S. , Rao Z. , Hu S. D.
Published: February 2014

This study proposes a concept of flexoelectric sensing on a cylindrical shell. A flexoelectric patch laminated on the cylindrical shell serves as the sensor to monitor dynamic states of the shell. The flexoelectric sensing signal is generated due to the mechanical strain gradient of the flexoelectric patch when the cylindrical shell is subjected to mechanical excitations. Based on the direct flexoelectric effect, neural sensing signal of flexoelectric neuron is presented first. To be practical in engineering, generic flexoelectric sensing signal of a diagonal flexoelectric patch is further derived. The diagonal flexoelectric patch is adopted in order to find out the optimal orientation angle of the flexoelectric patch. The sensitivity of flexoelectric sensor is also defined and evaluated. Effects of the dimension ratio of flexoelectric patch, the orientation angle and the natural mode number on flexoelectric sensitivity are investigated in case studies. Results show that with normalized modal participation factor, the amplitude of neural sensitivity increases with the mode number. Signal average effect occurs when the flexoelectric patch becomes longer and the sensing signal is significantly reduced when the flexoelectric patch covers more than a half-wave length of the mode due to the signal cancellation effect. The flexoelectric sensitivity is greatly dependent on the orientation angle and based on the analytical expression the optimal orientation angle can be determined with specified structure parameters.
How Should an Electric Vehicle Sound? User and Expert Perception
Authors: Petiot Jean-François , Kristensen Bjørn G. , Maier Anja M.
Published: February 2014

As electric vehicles are moving in on the automobile market, safety relating to acoustic perception is an important issue. It is a growing concern, particularly with respect to pedestrians, cyclists or visually impaired people. This can be addressed by adding sounds to the vehicle whilst at low speed. However, adding artificial sounds to an electric vehicle begs the question as to what kind of sound is appropriate. Appropriateness concerns technical specifications and is also linked to affective reactions of recipients of such a sound. Emotional reactions to 17 artificial exterior sounds for electric vehicles were investigated in an experimental setting with a total of 40 participants, 34 novice users and six sound experts.

Word association was used to elicit emotional reactions to the different sounds. Novice users employ more character-related terms to describe the sounds, while experts use more composition-based words. Analysis of variance and conjoint analysis was used to analyze participants’ assessments of sounds according to two semantic scales (pleasantness and appropriateness). Considerable inter-individual differences in the ratings of pleasantness and appropriateness indicate a great diversity of opinion about the sounds. Novice users indicate their preference for the sound of the traditional combustion engine as a possible proposition. Whilst participants saw the necessity, there was generally little enthusiasm for adding sounds to electric vehicles. The contribution of the paper concerns the methodology to analyze the results of the experiment and implications for the design of sounds for electric vehicles.
Numerical and Experimental Analysis of Flexible Pin Mechanisms for Load Balancing in Planetary Gear Drives
Authors: Yeh Hsiang-Yu , Tsai Shyi-Jeng , Yu Yuan-Yi
Published: February 2014

Load balancing mechanism is an important design for planetary gear drives. Among the well-known designs the flexible pin mechanism has advantage for even load sharing among more than three planet gears. However, there is no sufficient information about how to design such mechanisms. The goal of the paper is to propose an analysis approach of flexible pin mechanisms for planetary gear drives numerically and experimentally. Two types of flexible pin mechanisms are analyzed in the study, a conventional design and a novel design. Numerical analysis is carried out by software KISSsoft and FEM to evaluate the influence of the design parameters of flexible pin mechanism on the deformation performance. An experiment was finally conducted to verify the analysis results.
A Product-Service System Model for Identifying Design Factors
Authors: Moon Seung Ki , Oh Hyung Sool , Kim Samyeon
Published: February 2014

In competitive market environments, strategies that adding services to products for sales promotion are now moved to integrate products and services for satisfying diverse customer needs, and the number of these cases is gradually increasing. Trends of integrating products and services lead to the emergence of a product-service system (PSS). To implement and embody a PSS solution in new product development, a comprehensive design framework is allowed designers to facilitate the design factors of the PSS in complex business environments. The objective of this paper is to propose a PSS model to identify design factors for developing products and services by integrating object-oriented concepts and blueprinting in context of a business ecosystem. The proposed model is developed based on relationship between products and services matching with their design factors. The products and the services are then brought together to form a PSS. Functions and processes can be categorized to identify the design factors in different levels using the object-oriented concepts. Interaction between products and services lies on a PSS platform to form a product service system in blueprinting. To demonstrate of the effectiveness of the proposed model, we use a case study involving a smart phone.
Capturing Consumer Preference Through Experiential Conjoint Analysis
Authors: Tovares Noah , Cagan Jonathan , Boatwright Peter
Published: February 2014

Traditionally, consumer preference is modeled in terms of preference for the aesthetic and functional features of a product. This paper introduces a new means to model consumer preference that allows for the experience of and interaction with a product to account for not only for how a product looks and functions, but also how it feels to use it. Traditional conjoint-based approaches to preference modeling require a user to judge preference for a product based upon a 2D product representation or a feature list. While the aesthetic forms and functional features of a product are certainty important, the decision to buy or not to buy a product often depends on more, namely the experience or feel of use. We introduce the concept of experiential conjoint analysis, a method to mathematically capture preference for a product through experience-based preference judgments. Experience-based preference judgments are made based upon the use, or simulated use, of a product. For many products, creating enough physical prototypes to generate a preference model is cost prohibitive. In this work, virtual reality technologies are used to allow the subjects an interactive, immersive, and realistic product experience, provided at little investment. The results of this work show not only that preference judgments of the interaction of a 3D virtual product representation can be used to generate accurate preference models, but that non-experiential judgments of the same product’s 2D forms lead to the generation of different preference models. Further, the virtual reality experience is found to provide an advantage in the form of confidence, information, and/or realism. Such experiential-based preference models provide previously unavailable design insight with which to inform the design generation process.
Movable Focal-Type 7-Bar Baranov-Truss Linkages
Authors: Lee Chung-Ching , Lo Chien-Yu
Published: February 2014

Baranov truss is a structural framework composed of revolute jointed bars. It is also regarded as an Assur kinematic chain (briefly termed AKC) in viewpoint of kinematics. Based on Grübler mobility criterion, these AKCs with zero DoF should be generally unmovable. However, under some specified dimensional constraints, they have the constrained motion. In the paper, we focus on identifying mobility constraints of the simplified planar 7-bar Type-I Baranov-truss (AKC-I) linkage and on synthesizing one novel family of movable focal-type 7-bar linkages. In the beginning, applying the vector-loop approach produces the algebraic relations between structural parameters and angular variables of the simplified 7-bar such linkages. Next, by Sylvester elimination method, we attain one algebraic polynomial, which is function of an input variable only, and propose the mobility dimensional constraints of such truss architecture. Moreover, following the graphical technique for generating Kempe focal linkages, we systematically synthesize eight kinds of new movable focal-type 7-bar Baranov-truss linkages by removing one specified redundant link. These synthesized linkages further confirm the accuracy and availability of the derived mobility dimensional constraints.
Versatile and Coordinated Industry Framework: A Homo-Mimetic Model
Authors: Fukuda Shuichi
Published: February 2014

This paper points out that if we learn from humans how they sense and actuate, we could revolutionize our industry framework, and reduce energy consumption enormously in addition to satisfying our customers more.

Our body movements are very well coordinated and our brain and body work together. What humans teach us is that versatility, connectivity and coordination are very important.

But current industry and engineering are built for-a specific purpose and we forgot how we can develop products that will be connected with each other and operate together. If such industry framework is available, then industries will work together in a more versatile and coordinated manner. Such connected product developments will serve to make our industries more resilient, robust and adaptive to widely and quickly changing situations in addition to reducing energy consumption.

Thus, moving in such a direction is not only good for energy but also for meeting diversifying needs. Thus, it serves not only for each industry but also for society.
Generation Simulation and Grinding Experiment of Face-Gear Based on Single Index Generating Method
Authors: Guo Hui , Zhao Ning , Zhang Shuyan
Published: February 2014

A mathmatical model of generating face-gear by grinding disk is developed. The influence of all kinds of errors of alignment and profile on face-gear flank deviation is considered and investigated in this model, such as offset error and pressure angle error of grinding disk, location error of virtual pinion axis. A optimization method for decreasing flank deviation is proposed. The corresponding correction parameters of machine which can be used for manufacturing face gear can be computed by this optimization method. In this method, the square sum of tooth surface deviation is taken to be the objective function. A grinding experiment of face-gear is performed on a CNC grinding machine with five degrees of freedom, and the tooth flank deviation is measured on gear measuring center. The flank deviation is very large due to some alignment errors in the beginning. When the grinding machine is adjusted by optimization computation results mentioned above, the measurement results show that the deviation of grinded face-gear flank is reduced substantially. The benefit is to improve the grinding quality of face-gear by this method.
Tunable Vibration Absorption of a Cantilever Beam Utilizing Fluidic Flexible Matrix Composites
Authors: Zhu Bin , Rahn Christopher D. , Bakis Charles E.
Published: February 2014

Bonding a fluidic flexible matrix composite (F2MC) tube to a cantilever beam can create a lightly damped tuned vibration absorber. The beam transverse vibration couples with the F2MC tube strain to generate flow into an external accumulator via a flow port. The fluid inertia is analogous to the vibration absorbing mass in a conventional tuned vibration absorber. The large F2MC tube pressure accelerates the fluid so that the developed inertia forces cancel most of the vibration loads. An analytical model is developed based on Euler-Bernoulli beam theory and Lekhnitskii’s solution for anisotropic layered tubes. The analysis results show that the cantilever beam vibration can be reduced by more than 99% by designing the F2MC fiber angle, the tube attachment points, and the flow port geometry.
Extensible-Link Kinematic Model for Determining Motion Characteristics of Compliant Mechanisms
Authors: Beroz Justin , Awtar Shorya , Hart A. John
Published: February 2014

We present an extensible-link kinematic model for characterizing the motion trajectory of an arbitrary planar compliant mechanism. This is accomplished by creating an analogous kinematic model consisting of links that change length over the course of actuation to represent elastic deformation of the compliant mechanism. Within the model, the motion trajectory is represented as an analytical function. By Taylor series expansion, the trajectory is expressed in a parametric formulation composed of load-independent and load-dependent terms. Here, the load-independent terms are entirely defined by the shape of the undeformed compliant mechanism topology, and all load-geometry interdependencies are captured by the load-dependent terms. This formulation adds insight to the process for designing compliant mechanisms for high accuracy motion applications because: (1) inspection of the load-independent terms enables determination of specific topology modifications for improving the accuracy of the motion trajectory; and (2) the load-dependent terms reveal the polynomial orders of principally uncorrectable error components of the motion trajectory. The error components in the trajectory simply represent the deviation of the actual motion trajectory provided by the compliant mechanism compared to the ideally desired one. We develop the generalized model framework, and then demonstrate its utility by designing a compliant micro-gripper with straight-line parallel jaw motion. We use the model to analytically determine all topology modifications for optimizing the jaw trajectory, and to predict the polynomial order of the uncorrectable trajectory components. The jaw trajectory is then optimized by iterative finite elements (FE) simulation until the polynomial order of the uncorrectable trajectory component becomes apparent.
Design of a System for Upper-Limb Rehabilitation Based on an Electromechanical Orthosis and sEMG Wireless Sensors
Authors: Gentile Marco , Iualè Matteo , Mengoni Maura , Germani Michele
Published: February 2014

Nowadays, upper-limb injury or impairment represent a widespread problem, related to sport accidents or traumas, surgery operations, stroke and so on. The typical approach to the rehabilitation is one or more physiotherapy sessions, to restore muscular mass and strength. Despite this, over the years, several works proposed innovative solutions, including electromechanical orthoses, which work in relation to the muscular activity, measured by techniques such as superficial electromyography (sEMG). Yet, these systems are still far from commercialization because of their cost, complexity and difficulties in using. A currently unmet need regards the ability of the therapist to control and manage data through a remote interface, by exploiting some of the latest technological resources on the market (smartphones, tablets). The present works aims at designing an upper-limb rehabilitation system, based on an orthosis, sEMG wireless sensors and a dedicated software architecture to overcome these limitations. This will lead to an important change of perspective in physiotherapy procedures since data collection and correlation will produce innovative medical protocols, addressed to people affected by several types of injury or impairment.
Simple Measurement and Annotation Technique of Real Objects in Augmented Reality Environments
Authors: Caruso Giandomenico , Polistina Samuele , Bordegoni Monica
Published: February 2014

The paper describes a technique that allows measuring and annotating real objects in an Augmented Reality (AR) environment. The technique is based on the marker tracking, and aims at enabling the user to define the three-dimensional position of points, within the AR scene, by selecting them directly on the video stream. The technique consists in projecting the points, which are directly selected on the monitor, on a virtual plane defined according to the bi-dimensional marker, which is used for the tracking. This plane can be seen as a virtual depth cue that helps the user to place these points in the desired position. The user can also move this virtual plane to place points within the whole 3D scene. By using this technique, the user can place virtual points around a real object with the aim of taking some measurements of the object, by calculating the minimum distance between the points, or in order to put some annotations on the object. Up to date, these kinds of activities can be carried out by using more complex systems or it is needed to know the shape of the real object a priori. The paper describes the functioning principles of the proposed technique and discusses the results of a testing session carried out with users to evaluate the overall precision and accuracy.
Computing the Stresses Induced Within Multi-Layered Elastic Media That Result From Sliding Contact With a Rigid Punch
Authors: Chidlow Stewart , Teodorescu Mircea
Published: February 2014

This paper is concerned with the solution of the contact problem that results when a rigid punch is pressed into the surface of an inhomogeneously elastic solid comprising three distinct layers. The upper and lower layers of the solid are assumed to be homogeneous and are joined together by a functionally graded interlayer whose material properties progressively change from those of the coating to those of the substrate.

By applying the Fourier transform to the governing boundary value problem (BVP), we may write the stresses and displacements within the solid in terms of indefinite integrals. In particular, the expressions for the horizontal and vertical displacements of the solid surface are used to formulate a coupled pair of integral equations which may be solved numerically to approximate the solution of the stamp problem. A selection of numerical results are then presented which illustrate the effects of friction on the contact problem and it is found that the presence of friction within the contact increases the magnitude of the maximum principal stress and changes its location. These observations indicate that material failure is much more likely to occur when friction is present within the contact as expected.
Design of Thin Film Solar Cell Material Structures for Reliability and Performance Robustness
Authors: Yodo Nita , Wang Pingfeng
Published: February 2014

An exponential growth of photovoltaic (PV) technologies in the past decade has paved a path to a sustainable solar-powered world. The development of alternative PV technologies with low-cost and high-stability materials has attracted a growing amount of attention. One of these alternatives is the use of second generation thin film PV technologies. However, even in the presence of their bandgap properties, a major issue faced by most thin film solar cells is the low output efficiency due to manufacturing variability and uncertain operating conditions. Thus, to ensure the reliability and performance robustness of the thin film PV technologies, the design of the solar cell is studied. To represent the thin film PV technologies, a copper gallium (di)selenide (CIGS) solar cell model is developed and optimized with Reliability-based Robust Design Optimization (RBRDO) method. This model takes into account the variability of the structure and the material properties of the CIGS solar cells, and assumes an ideal-weather operating condition. This study presents a general methodology to optimize the design of the CIGS PV technologies and could be used to facilitate the development and assessment of new PV technologies with more robust performance in efficiency and stability.
A Harmonic Balance Approximation of Dynamic Snap-Through Boundaries in a Single-Degree-of-Freedom Structure
Authors: Wiebe Richard , Virgin Lawrence N.
Published: February 2014

Under dynamic loading, systems with the requisite condition for snap-through buckling, that is co-existing equilibria, typically exhibit either small amplitude response about a single equilibrium configuration, or large amplitude response that transits between the static equilibria. Dynamic snap-through is the name given to the large amplitude response, which, in the context of structural systems, is obviously undesirable.

Structures with underlying snap-through static behavior may exhibit highly nonlinear and unpredictable oscillations. Such systems rarely lend themselves to investigation by analytical means. This is not surprising as nonlinear phenomena such as chaos run counter to the predictability of an analytical closed form solution. However, many unexpected analytical approximations of global stability may be obtained for simple systems using the harmonic balance method.

In this paper a simple single-degree-of-freedom arch is studied using the harmonic balance method. The equations developed with the harmonic balance approach are then solved using an arc-length method and an approximate snap-through boundary in forcing parameter space is obtained. The method is shown to exhibit excellent agreement with numerical results. Arches present an ideal avenue for the investigation of snap-through as they typically have multiple, often tunable, stable and unstable equilibria. They also have many applications in both civil engineering, where arches are a canonical structural element, and mechanical/aerospace engineering, where arches may be used to approximate the behavior of curved plates and panels such as those used on aircraft.
Automatically Inferring Metrics for Design Creativity
Authors: Fuge Mark , Stroud Josh , Agogino Alice
Published: February 2014

Measuring design creativity is crucial to evaluating the effectiveness of idea generation methods. Historically, there has been a divide between easily-computable metrics, which are often based on arbitrary scoring systems, and human judgement metrics, which accurately reflect human opinion but rely on the expensive collection of expert ratings. This research bridges this gap by introducing a probabilistic model that computes a family of repeatable creativity metrics trained on expert data. Focusing on metrics for variety, a combination of submodular functions and logistic regression generalizes existing metrics, accurately recovering several published metrics as special cases and illuminating a space of new metrics for design creativity. When tasked with predicting which of two sets of concepts has greater variety, our model matches two commonly used metrics to 96% accuracy on average. In addition, using submodular functions allows this model to efficiently select the highest variety set of concepts when used in a design synthesis system.
Towards Understanding the Role of Interaction Effects in Visual Conjoint Analysis
Authors: Sylcott Brian , Michalek Jeremy J. , Cagan Jonathan
Published: February 2014

We investigate consumer preference interactions in visual choice-based conjoint analysis, where the conjoint attributes are parameters that define shapes shown to the respondent as images. Interaction effects are present when preference for the level of one attribute is dependent on the level of another attribute. When interaction effects are negligible, a main-effects fractional factorial experimental design can be used to reduce data requirements and survey cost. This is particularly important when the presence of many parameters or levels makes full factorial designs intractable. However, if interaction effects are relevant, a main-effects design creates biased estimates and potentially misleading conclusions. Most conjoint studies assume interaction effects are negligible; however, interactions may play a larger role for shape parameters than for other types of attributes. We conduct preliminary tests on this assumption in three visual conjoint studies. The results suggest that interactions can be either negligible or dominant in visual conjoint, depending on both consumer preferences and shape parameterization. When interactions are anticipated, it is possible in some cases to re-parameterize the shape such that interactions in the new space are negligible. Generally, we suggest that randomized designs are better than fractional factorial designs at avoiding bias due to the presence of interactions and/or the organization of profiles into choice sets.
On Vibration Control Using a Bistable Snap Through Absorber From a Force Balance Perspective
Authors: Johnson David R. , Harne R. L. , Wang K. W.
Published: February 2014

One approach to vibration control is to apply a force to a primary structure which opposes excitation, effectively canceling the external disturbance. A familiar passive example of this approach is the linear tuned mass absorber. In this spirit, the utility of a bistable attachment for attenuating vibrations, especially in terms of the high-orbit, snap through dynamic, is investigated using the harmonic balance method and experiments. Analyses demonstrate the fundamental harmonic snap through dynamic, having commensurate frequency with the single-frequency harmonic excitation, may yield displacements either substantially in-phase or out-of-phase with the primary structure. During in-phase snap through, forces are generated by the bistable oscillator which reinforce the applied loading, resulting in dramatic amplification of primary system response. During out-of-phase snap through, forces are generated which are only partially opposed to the input, leading to a measure of host structure attenuation. The experiments verify the analytical findings and also uncover nonlinear dynamics not predicted by the analysis that have slightly favorable vibration suppression performance when compared with the out-of-phase, fundamental harmonic snap through action.
Comparing LQG/LTR and the SDRE Techniques for Hybrid Fully-Connected PLL Network Control
Authors: Bueno Átila Madureira , Tusset Angelo Marcelo , Ferruzzo Correa Diego Paolo , Castilho Piqueira José Roberto , Balthazar José Manoel
Published: February 2014

Synchronization plays an important role in telecommunication systems and integrated circuits. The Master-Slave is a commonly used strategy for clock signal distribution. However, due to the wireless networks development and the higher operation frequency of integrated circuits, the Mutually-Connected clock distribution strategies are becoming important, and the Fully-Connected strategy appears as a convenient engineering solution. The main drawback of the Fully-Connected architecture is the definition of control algorithms that assure the stability of the network sinchronization. In hybrid synchronization techniques groups of nodes synchronized by the Fully-Connected architecture are synchronized with network master clocks by using the Master-Slave tecnique. In this arrangement, if a route of clock signal distribution becomes inoperative, the group of Fully-Connected nodes retain for some time the original phase and frequency received from the network. The Fully-Connected architecture complexity imposes difficulties to satisfy both stability and performance requirements in the control system design. For that reason the multi-variable LQG/LTR and the SDRE control techniques are applied in order to fulfill both stability and performance requirements. The performance of both techniques are compared, and the results seems to confirm the improvement in the transient response and in the precision of the clock distribution process.
Design Optimization of a Solar-Powered Reverse Osmosis Desalination System for Small Communities
Authors: Kim Jihun , Hamza Karim , El Morsi Mohamed , Nassef Ashraf O. , Metwalli Sayed , Saitou Kazuhiro
Published: February 2014

Fresh water availability is essential for the economic development in small communities in remote areas. In desert climate, where naturally occurring fresh water is scarce, seawater or brackish water from wells is often more abundant. Since water desalination approaches are energy intensive, a strong motivation exists for the design of cost-effective desalination systems that utilize the abundant renewable energy resource; solar energy. This paper presents an optimization model of a solar-powered reverse osmosis (RO) desalination system. RO systems rely on pumping salty water at high pressure through semi-permeable membrane modules. Under sufficient pressure, water molecules will flow through the membranes, leaving salt ions behind, and are collected in a fresh water stream. Since RO system are primarily powered via electricity, the system model incorporates photovoltaic (PV) panels, and battery storage for smoothing out fluctuations in the PV power output, as well as allowing system operation for a number of hours after sunset. Design variables include sizing of the PV solar collectors, battery storage capacity, as well as the sizing of the RO system membrane module and power elements. The objective is to minimize the cost of unit volume produced fresh water, subject to constraints on production capacity. A genetic algorithm is used to generate and compare optimal designs for two different locations near the Red Sea and Sinai.
A Survey of Standards for Product Lifecycle Management of Structural Composites
Authors: Ameta Gaurav , Brown Christopher , Lubell Joshua , Lipman Robert
Published: February 2014

Composite materials are widely used in the aerospace, automotive, and sports industries. Designing a composite product requires highly concurrent processes including manufacturing and assembly considerations. This paper examines existing classification schemes for composite materials based on reinforcement and matrix type. Next we review various research, industry, and standards organization efforts to develop computer representation models of composite materials. We then present a survey of specification and verification standards for composite materials, highlighting their gaps and overlaps. Key findings of our analysis are that standard test methods are lacking for particle-reinforced composite materials, and that existing bonding inspection methods and computer-aided design presentation methods for layered composite materials need improvement.
Rendering Physical 2D Cross-Sections of Aesthetic Shapes Driven by Equidistant Interpolation Points
Authors: Covarrubias Mario , Bordegoni Monica , Cugini Umberto
Published: February 2014

The paper describes a desktop-haptic interface (DHI) that has been conceived to support designers in the evaluation and modification of aesthetic virtual shapes. The objective in designing this device is to reproduce a 2D cross-section of virtual objects with a consistent physical rendering well adapted to designers needs allowing a continuous and smoothly free hand contact interaction on a real and developable metallic strip. The desktop-haptic interface consists in a servo-actuated metallic strip that has been devised and implemented by using the Minimal Energy Curve (MEC) spline approach in which the equidistant interpolation points scheme has been adopted for modeling the structure chain consisting of several rigid struts and pivots. Then, we present the co-simulation between the multi-body environment and MATLAB/Simulink used for achieving this goal and control the system and finally, we present the results of the experimental validation session specifically carried out to evaluate the accuracy and the effectiveness of the interface.
Indexing Methods for Discrete Mode Pursuing Sampling
Authors: Gjernes Tim A. P. , Li Hanbo , Hajikolaei Kambiz H. , Wang G. Gary , Arzanpour Siamak
Published: February 2014

Discrete Mode Pursuing Sampling (D-MPS) is a method used for optimization of expensive black-box functions with discrete variables. The type of discrete space where all possible combinations of discrete values of all variables are valid design points is called a full grid of points or a “regular grid” in this paper. A regular structure for sampling data is a requirement when D-MPS is applied. This paper presents two new indexing methods, i.e. “n-D” and “distance”, to transform non-regular discrete data sets into regular data sets. The n-D indexing method sorts data by all the axes, regardless of the function values. The distance indexing method sorts data dynamically by its distance from the current mode. A number of optimization problems are used to test the performance of the two methods in comparison with a 1-D indexing method which simply sorts data by a single axis. Both n-D and distance methods give much better performance than the 1-D. It is concluded that the distance indexing method can be recommended for most applications. While this paper uses D-MPS as the test bed, the indexing methods are applicable to other discrete optimization methods.
Mixed Discrete and Continuous Variable Optimization Based on Constraint Aggregation and Relative Sensitivity
Authors: Jiang Zhansi , Cheng George H. , Wang G. Gary
Published: February 2014

This work presents a new approach for solving nonlinear mixed discrete-continuous variable problems with constraints. The proposed method falls under the category of direct search methods for discrete variables. Different from the traditional direct search methods that determine the search direction based on decreasing objective function within the feasible space, a relative sensitivity that jointly considers change in objective and constraint functions is introduced in this work to help determining the search direction. For feasible discrete points, the coordinate direction with the maximum relative sensitivity is taken as the search direction, so that the objective function value decreases the fastest with minimum increase in constraint values. For infeasible points, the search direction is determined by the minimum relative sensitivity, so that the points can be dragged into the feasible region with constraints decreasing the fastest and minimum increase of the objective. In addition, in order to reduce the number of constraints and calculate the relative sensitivity, a constraint aggregation technique with Kreisselmeier-Steinhauser function is applied to transform all constraints into an equivalent differentiable inequality constraint. The efficacy and accuracy of the proposed approach is demonstrated with different types of test problems and application to a design problem. The proposed method has advantages in solving nonlinear mixed discrete-continuous variable problems with constraints compared to other existing methods.
Joining Unfoldings of 3-D Surfaces
Authors: Sung Cynthia , Demaine Erik D. , Demaine Martin L. , Rus Daniela
Published: February 2014

Origami-based design methods enable complex devices to be fabricated quickly in plane and then folded into their final 3-D shapes. So far, these folded structures have been designed manually. This paper presents a geometric approach to automatic composition of folded surfaces, which will allow existing designs to be combined and complex functionality to be produced with minimal human input. We show that given two surfaces in 3-D and their 2-D unfoldings, a surface consisting of the two originals joined along an arbitrary edge can always be achieved by connecting the two original unfoldings with some additional linking material, and we provide an algorithm to generate this composite unfolding. The algorithm is verified using various surfaces, as well as a walking and gripping robot design.
Dynamic Analysis of Mooring Cable Fastening a Floating Sphere on the Ocean
Authors: Zhu Xiang Q. , Yoo Wan S. , Bauchau Olivier A.
Published: February 2014

Mooring cable system, fastening the floating platform is an indispensable segment in the development and utilization of ocean energy. However, the nonlinear cable geometry and nonlinear hydrodynamic forces perplex the construction of numerical modelling of mooring cable. Traditionally, the cable modelling is constructed just considering the geometry of cable, the normal, and the tangential directions. Not only the geometry of cable, but also the relative velocity of fluid is involved in constructing of the numerical modelling of cable in this paper. The expression of external loads by this numerical modelling is effective and accurate taking advantage of explicit separation of external loads in transverse and lengthwise directions. This modelling also simplified the formulation of hydrodynamic drag forces which is dominant among external loads. The stiffness and damping of cable, apparent weight, hydrodynamic drag forces, effect of added mass, and Froude-Krylov force are considered during building of this numerical modelling. The mooring cable fastening a floating sphere stands on buoyancy forces due to the submerged sphere. The simulation results of this numerical modelling were compared and verified with the results from ProteusDS which is an offshore simulation code.
Assessing Long-Term Wind Conditions by Combining Different Measure-Correlate-Predict Algorithms
Authors: Zhang Jie , Chowdhury Souma , Messac Achille , Hodge Bri-Mathias
Published: February 2014

This paper significantly advanced the hybrid measure-correlate-predict (MCP) methodology, enabling it to account for the variations of both wind speed and direction. The advanced hybrid MCP method used the recorded data of multiple reference stations to estimate the long-term wind condition at the target wind plant site with greater accuracy than possible with data from a single reference station. The wind data was divided into different sectors according to the wind direction, and the MCP strategy was implemented for each wind sector separately. The applicability of the proposed hybrid strategy was investigated using four different MCP methods: (i) linear regression; (ii) variance ratio; (iii) artificial neural networks; and (iv) support vector regression. To implement the advanced hybrid MCP methodology, we used the hourly averaged wind data recorded at six stations in North Dakota between the years 2008 and 2010. The station Pillsbury was selected as the target plant site. The recorded data at the other five stations (Dazey, Galesbury, Hillsboro, Mayville, and Prosper) was used as reference station data. The best hybrid MCP strategy from different MCP algorithms and reference stations was investigated and selected from the 1,024 combinations. The accuracy of the hybrid MCP method was found to be highly sensitive to the combination of individual MCP algorithms and reference stations used. It was also observed that the best combination of MCP algorithms was strongly influenced by the length of the correlation period.
Phenomena on Rogue Waves and Rational Solution of Korteweg-de Vries Equation
Authors: Song Ni , Zhang Wei , Wang Qian
Published: February 2014

An appropriate nonlinear mechanism may create the rogue waves. Perhaps the simplest mechanism, which is able to create considerate changes in the wave amplitude, is the nonlinear interaction of shallow-water solitons. The most well-known examples of such structure are Korteweg-de Vries (KdV) solitons. The Korteweg-de Vries (KdV) equation, which describes the shallow water waves, is a basic weakly dispersive and weakly nonlinear model. Basing on the homogeneous balanced method, we achieve the general rational solution of a classical KdV equation. Numerical simulations of the solution allow us to explain rare and unexpected appearance of the rogue waves. We compare the rogue waves with the ones generated by the nonlinear Schrödinger (NLS) equation which can describe deep water wave trains. The numerical results illustrate that the amplitude of the KdV equation is higher than the one of the NLS equation, which may causes more serious damage of engineering structures in the ocean. This nonlinear mechanism will provide a theoretical guidance in the ocean and physics.
Implicit Boundary Approach for Reissner-Mindlin Plates
Authors: Chen Hailong , Kumar Ashok V.
Published: February 2014

Implicit boundary method enables the use of background mesh to perform finite element analysis while using solid models to represent the geometry. This approach has been used in the past to model 2D and 3D structures. Thin plate or shell-like structures are more challenging to model. In this paper, the implicit boundary method is shown to be effective for plate elements modeled using Reissner-Mindlin plate theory. This plate element uses a mixed formulation and discrete collocation of shear stress field to avoid shear locking. The trial and test functions are constructed by utilizing approximate step functions such that the boundary conditions are guaranteed to be satisfied. The incompatibility of discrete collocation with implicit boundary approach is overcome by using irreducible weak form for computing the stiffness associated with essential boundary conditions. A family of Reissner-Mindlin plate elements is presented and evaluated in this paper using several benchmark problems to test their validity and robustness.
Type Synthesis of 3-DOF Translational Compliant Parallel Mechanisms
Authors: Yue Cong , Su Hai-Jun , Kong Xianwen
Published: February 2014

In this paper, we apply screw theory to the type synthesis of compliant parallel mechanisms (PMs). Compliant PMs are formed by a moving stage supported by three or more limbs each of which is a serial chain of flexure joints and rigid bodies. They achieve movement through the deformation of flexure joints and have been widely used in precision machinery. As an important task in the conceptual design stage, the goal of type synthesis is to determine the chain of each limb as well as their relationship when they are assembled in parallel for a prescribed motion pattern. Our approach starts with a category of commonly used flexure primitives and flexure elements whose freedom and constraint spaces are characterized by twists and wrenches in screw theory. Following the well-studied synthesis procedure for rigid body PMs, we propose a synthesis procedure for compliant PMs via screw theory. This procedure consists of four basic steps: decomposition of the screw system of the constraint space, type synthesis of limbs, assembling limbs and design of flexure joints. As an example, we demonstrate the procedure for synthesizing compliant PMs for three degree-of-freedom (DOF) translational motions. Tables of limbs, types and geometric conditions for the assemblies of these limbs are presented. The paper provides a catalogue of compliant PM designs with three translational motions. At last, we provide a case study of applying finite element simulation to validate one of the synthesized designs.
Optimal Random Search, Fractional Dynamics and Fractional Calculus
Authors: Zeng Caibin , Chen YangQuan
Published: February 2014

What is the most efficient search strategy for the random located target sites subject to the physical and biological constraints? Previous results suggested the Levy flight is the best option to characterize this optimal problem, however, which ignores the understanding and learning abilities of the searcher agents. In the paper we propose the Continuous Time Random Walk (C-TRW) optimal search framework and find the optimum for both of search length’s and waiting time’s distributions. Based on fractional calculus technique, we further derive its master equation to show the mechanism of such complex fractional dynamics. Numerous simulations are provided to illustrate the non-destructive and destructive cases.