bluuebunny/crossref_metadata_2025 huggingface dataset:
Developing New Design Requirements to Reduce Failures in Early Complex Systems Design
Authors: O’Halloran Bryan M. , Stone Robert B. , Tumer Irem Y.
Published: February 2014

In this paper, we develop a method that produces recommendations, usable by a designer, that reduce the likelihood of a failure occurring. Prior work introduced the Function Failure Rate Design Method (FFRDM) which uses historical data as evidence to generate new design requirements. This paper presents improvements to FFRDM by including an iterative loop within the method that begins with specific recommendations. This allows evidence from the analysis to support the addition of new requirements and functionality into the design. Once the iterative loop has converged with no new requirements left to generate, all recommendations are used for concept generation. In addition, metrics are developed that can be used later to analyze the design. These metrics are important to ensure that the design has considered the full set of recommendations. Specifically, the updated FFRDM improves the original FFRDM with 1) a systematic and repeatable heuristic to group failure modes and determine which failure modes are predominate, 2) a categorization of the recommendations, 3) metrics built for the recommendations used in concept generation to make them measurable, and 4) using recommendations to develop new requirements and functionality. To show the usefulness of each improvement to FFRDM, a case study using an electrical power system (EPS) is provided.
Sustainability Characterization for Die Casting Process
Authors: Watkins Megan F. , Mani Mahesh , Lyons Kevin W. , Gupta S. K.
Published: February 2014

The manufacturing sector accounts for approximately one-third of the total energy consumption in the United States. Today, sustainable manufacturing has become an area of increasing interest, as companies look to reduce their manufacturing footprint and become more environmentally friendly. A science-based methodology, known as sustainability characterization, has the potential for providing companies a way to measure the sustainability of their manufacturing processes. In this paper, the sustainability characterization methodology was used to evaluate the sustainability of die casting unit manufacturing process. More specifically, a way to theoretically model sustainability, based on energy use, was investigated. Using the fundamentals of die casting processes, corresponding input-outputs were first mapped in terms of sustainability parameters and later equations to theoretically calculate the energy used in a die casting machine were identified/formulated. The theoretical energy equations provide a baseline for creating an information model that will eventually lead to creating a science-based methodology standard for sustainability characterization of unit manufacturing processes.
Modernization of Main Helicopter Gearbox With Asymmetric Tooth Gears
Authors: Shankin Sergey I. , Stupakov Alexander A. , Glikson Igor L. , Ananiev Viacheslav M. , Kapelevich Alexander L.
Published: February 2014

This paper describes the research and development of asymmetric tooth spur gears for modernization of the light multipurpose helicopter gearbox amplifying its load capacity to utilize more powerful turboshaft engines.

The paper also presents numerical design data related to development this gearbox.
Flexible Vision Based Control for Micro-Factories
Authors: Fontana Gianmauro , Ruggeri Serena , Fassi Irene , Legnani Giovanni
Published: February 2014

In the micro-manipulation field, the adoption of vision-based strategies can suitably support the motion system in easily performing precise manipulation operations. In this context, the cooperation between the robot and the vision system is fundamental to achieve high performance. The paper introduces and critically discusses the main issues related to the design and implementation of vision-based control for a micro-manipulation work-cell. The core issues of the developed software architecture, such as the work-cell calibration and the task execution module, are described and its main characteristics highlighted. The application of this program within a micro-assembly work-cell set-up allowed the execution of various manipulation operations, thus representing a test bench for its capabilities evaluation. The actual execution of a pick&place task is finally discussed.
Explicit Maps of Acoustic Regimes of a Wind Instrument
Authors: Missoum Samy , Vergez Christophe
Published: February 2014

An approach to map the various acoustic regimes of a wind instument is presented. In this work, the regimes are first classified based on the occurence or the lack of sound. Physically, the production of a sound corresponds to the existence of self-sustained oscillations in the resonator of the instrument, whereas the lack of sound is associated with a stable static regime. Another classification based on the sound frequency is also investigated. The maps are created in a space consisting of design and control parameters. The boundaries of the maps are obtained explicitly in terms of the parameters using a support vector machine classifier as well as a dedicated adaptive sampling scheme. The approach is applied to a simplified clarinet model.
Workspace Analysis of a Cable-Suspended Robot With Active/Passive Cables
Authors: Saber Omid , Zohoor Hassan
Published: February 2014

Cable-driven parallel robots have several outstanding characteristics that make them unique in many robotic applications. Since cables can only pull, one of the most important issues associated with these robots is obtaining their workspace. In this paper a spatial translational cable-driven robot with active/passive cables is considered and its workspace is investigated from several points of views. First the moment resisting capability of the robot is discussed and the effects of some robot’s parameters on the workspace are studied. Then, both force-feasibility and moment-resisting capability of the robot are considered to find the region where the end-effector may exert the required force-set and resist an external moment simultaneously. Furthermore, the wrench-feasibility of the redundant cable-driven robot is studied and finally a method of obtaining non-fluctuating positive tensions in all cables is proposed by using a particle swarm optimization approach.
Comparison of Marker-Based and Marker-Less Systems for Low-Cost Human Motion Capture
Authors: Puthenveetil Sajeev C. , Daphalapurkar Chinmay P. , Zhu Wenjuan , Leu Ming C. , Liu Xiaoqing F. , Chang Alpha M. , Gilpin-Mcminn Julie K. , Wu Peter H. , Snodgrass Scott D.
Published: February 2014

To generate graphic simulation of human motion, marker-based optical motion capture technology is widely used because of the accuracy and reliability of motion data provided by this technology. However, tracking of human motion without markers is very desirable on the factory floor because the human operator does not need to wear a special suit mounted with markers and there is no physical interference with the manufacturing or assembly operation during the motion tracking. In this paper, we compare marker-based and marker-less motion capture systems. First, the operational principles of these two different types of systems are compared. Then the quality of motion data obtained by a marker-less system using Kinect is compared with that obtained by a marker-based system using Optitrack cameras. The comparison also includes the accuracy of body joint angles and variations in body segment lengths measured by the two different systems. Furthermore, we compare the human motion simulation developed in the Jack digital human modeling software using the data captured by these two systems when a person is performing a fastening operation on a physical mockup of the belly section of an aircraft fuselage.
Realtime Rigid Folding Algorithm for Quadrilateral-Based 1-DOF Tessellations
Authors: Klett Yves
Published: February 2014

Origami tessellations consisting of repetitively tiled unit cell elements can be used to manufacture cellular three-dimensional structures with interesting mechanical and other properties. In recent years, the search for alternative and innovative core materials for sandwich constructions has resulted in renewed interest in such foldable structures. The ability to simulate the folding process of such structures with one kinematic degree of freedom is essential for their successful design and manufacture. We present an algorithm that allows for the implicit calculation of arbitrary rigid folding states of quadrilateral-based structures with certain topological features. This enables reliable real-time virtual folding of a large number of important tessellation types which has been put to good use in numerous projects.
A Knowledge-Based Approach for the Automated Design of Robotic/Human Manufacturing Workcells in Hazardous Environments
Authors: Williams Joshua M. , Pryor Mitch W.
Published: February 2014

The design of manufacturing systems in hazardous environments is complex, requiring interdisciplinary knowledge to determine which components and operators (human or robotic) are feasible. When conceptualizing designs, some options may be overlooked or unknowingly infeasible due to the design engineers’ lack of knowledge in a particular field or ineffective communication of requirements between disciplines. Computational design tools can help alleviate many of the problems encountered in this design task. We create a knowledge-based system (KBS) utilizing CLIPS to automate the synthesis of conceptual manufacturing system designs in radioactive environments. The KBS takes a high-level functional description of a process and uses FBS modeling to generate multiple designs with generic components retrieved from a database and low-level manufacturing task sequences. Using this approach, many options are explored and operator task compatibility is directly addressed. The KBS is applied to the design of glovebox processing systems at Los Alamos National Laboratory (LANL).
An Improved Free Energy Formulation and Implementation for Kinetostatic Protein Folding Simulation
Authors: Tavousi Pouya , Behandish Morad , Kazerounian Kazem , Ilieş Horea T.
Published: February 2014

Protein structure prediction remains one of the significant challenges in computational biology. We have previously shown that our kinetostatic compliance method can overcome some of the key difficulties faced by other de novo structural prediction methods, such as the very small time steps required by the molecular dynamics approaches, or the very large number of samples required by the sampling based techniques. In this paper we extend the previous free energy formulation by adding the solvent effects, which contribute predominantly to the folding phenomena. We show that the addition of the solvation effects, which complement the existing Coulombic and van der Waals interactions, lead to a physically effective energy function. Furthermore, we achieve significant computational speed-up by employing efficient algorithms and data structures that effectively reduce the time complexity from O(n2) to O(n), n being the number of atoms. Our simulations are consistent with the general behavior observed in protein folding, and show that the hydrophobic atoms tend to pack inside the core of the molecule in an aqueous solvent, while a vacuum environment produces no such effect.
GPU-Accelerated Computation of Solvation Free Energy for Kinetostatic Protein Folding Simulation
Authors: Behandish Morad , Tavousi Pouya , Ilieş Horea T. , Kazerounian Kazem
Published: February 2014

A realistic computer simulation of protein folding requires a comprehensive account of interaction energetics, placing a substantial demand on processing power. This paper presents an improved computational framework for protein folding software package PROTOFOLD, that enables efficient computation of solvation free energy effects in addition to Coulombic and van der Waals interactions. Efficient data structures have been utilized to speed-up the sequential running times from O(n2) to O(n), n being the number of atoms. It turns out, however, that an accurate evaluation of molecular surface areas characterizing the solvation effects imposes a computational bottleneck to the entire simulation. Massive computational power offered by Graphics Processing Units (GPU) was exploited to develop a simple and efficient Single-Instruction Multiple-Thread (SIMT) algorithm for the latter step. The running times were monitored for different steps of the folding simulation for different molecular sizes. Significant performance improvements were observed, yielding promising results where numerous iterative runs are needed.
Quasi-Static Impact Response of Alternative Origami-Core Sandwich Panels
Authors: Gattas Joseph M. , You Zhong
Published: February 2014

Foldcore sandwich panels have been the focus of much recent study in the aerospace industry. Existing foldcores are composed of a partially folded Miura origami pattern sandwiched between two stiff facings, and have been shown to possess numerous useful properties for impact-resistant applications. Non-Miura origami pattern with similar geometric properties, specifically rigid-foldability and tessellation, may be used as potential alternative origami-cores for sandwich panels, however the mechanical performance of such cores remains an unexplored area. This paper conducts a preliminary investigation into the impact resistance of five non-Miura sandwich panels. The selected patterns are numerically analysed under quasi-static lateral impact loads, and comparisons are drawn with existing foldcore designs. Two particular patterns are found to have failure modes suited for energy-absorbing applications. Prototypes of these two cores are constructed from polypropylene sheet material and experimentally tested to validate numerical results. Reasonable correlation is seen in the force-displacement response of numerical and experimental models.
Expanding the Bottom-Up Design Approach Through Integrating Design Attitudes Into Set-Based Design
Authors: Canbaz Baris , Yannou Bernard , Yvars Pierre-Alain
Published: February 2014

In distributed design systems, designers are related to each other through couplings, however they have limited control over the design variables. Any inconsistency in the design system can result in design conflicts through these couplings. Modeling designer attitudes can help to understand inconsistencies and manage conflicts in design processes. We expand the bottom-up design approach through agent-based modeling techniques to another level where designers can make decisions directly on their wellbeing values that represent how their desires are satisfied. Set-based design and constraint programming techniques are used to explore the imprecision of the design activities. Monte Carlo simulations are performed to evaluate the performance of our approach. The results show that the number of design conflicts and their harshness can be lowered when the design process is defined with our approach.
A Data Mining Trajectory Clustering Methodology for Modeling Indoor Design Space Utilization
Authors: Han Yixiang , Tucker Conrad S. , Simpson Timothy W. , Davidson Erik
Published: February 2014

Traditionally, understanding indoor space utilization in a typical design setting has been based on observation methodologies, where researchers document team interactions, space utilization and design activities using qualitative observation techniques. The authors of this paper propose a data mining driven methodology aimed at modeling the utilization of indoor design spaces using trajectory pattern data. Using indoor Radio-frequency identification (RFID) technology, researchers are able to collect trajectory data which can then be used to quantify the distribution of space usage patterns over time and predict future regions of interest. The proposed methodology consists of two phases: i) trajectory partitioning and ii) line segment clustering. For the first phase, trajectories are partitioned into line segments, based on unique user characteristics. In the second phase, a data mining clustering algorithm is employed to group line segments into different clusters based on a distance function. Since individual trajectories may exhibit similar movement patterns, the proposed methodology can help designers better understand how design spaces are utilized and how team dynamics evolve over time, depending on the specific design task being executed. A 3,500 square foot design space was used for the semester long study that included design teams supervised by teaching assistants. The results provide insight into the underutilization of certain regions of the design space and proposes directions towards an optimal design space methodology.
Impacts of Government Policies, Fuel Cell Cost, and Battery Cost on Greenhouse Gas Emission of Light-Duty Vehicles
Authors: Razu Swithin S. , Takai Shun
Published: February 2014

The aim of this paper is to study the impact of public government policies, fuel cell cost, and battery cost on greenhouse gas (GHG) emissions in the US transportation sector. The model includes a government model and an enterprise model. To examine the effect on GHG emissions that fuel cell and battery cost has, the optimization model includes public policy, fuel cell and battery cost, and a market mix focusing on the GHG effects of four different types of vehicles, 1) gasoline-based 2) gasoline-electric hybrid or alternative-fuel vehicles (AFVs), 3) battery-electric (BEVs) and 4) fuel-cell vehicles (FCVs). The public policies taken into consideration are infrastructure investments for hydrogen fueling stations and subsidies for purchasing AFVs. For each selection of public policy, fuel cell cost and battery cost in the government model, the enterprise model finds the optimum vehicle design that maximizes profit and updates the market mix, from which the government model can estimate GHG emissions. This paper demonstrates the model using FCV design as an illustrative example.
Nonlinear Dynamics of the Active Magnetic Bearings System Up to the Second-Order Time Scale
Authors: Hu Wenhua , Zhang Wei , Wang Qian , Cao Dongxing , Yang Xiaofeng
Published: February 2014

As techniques develop, the AMBs are more widely utilized in engineering fields than ever before. Their performance depends on the actively control strategies due to their complicated dynamical characteristics, which mainly arise from the electromagnetic forces. Those forces usually are nonlinear functions of the displacements of the rotor and the control current. An understanding of the dynamical characteristics of these structural systems is essential for the rules of their designing and controlling. Variations of a long time could be observed easier with a quicker time scale. In order to study the AMBs’ action during a very long time, we use the perturbation method to obtain the AMBs’ motion up to second-order time scale. In present work, the horizontal and vertical motions of a rotor-AMBs system with 8-pole legs and the time-varying stiffness are formulated. We use the multiple scales method to study the simultaneous resonance of a 1:2 sub-harmonic resonance and a primary parametric resonance for this system up to the second-order time scale. With numerical simulation, we focus on the nonlinear dynamics describing the system’s approximate solution with regard to the second-order time scale. It is found that the modulations of the amplitudes and phases of the rotor-AMBs system in higher time scale could be severely affected by changing some parameters in governing equations.
Kinetostatic Design-Refinement of Articulated Knee Braces
Authors: Jun Seung-kook , Zhou Xiaobo , Ramsey Daniel K. , Krovi Venkat N.
Published: February 2014

Knee bracing has been used to realize a variety of functional outcomes in both sport and rehabilitation application. Much of the literature focuses on the effect of knee misalignment, force reduction and superiority of custom braces over commercial over-the-counter braces. Efforts on developing exoskeletons to serve as knee augmentation systems emphasize actuation of joints, which then adds to bulkiness of ensuing designs.

In lieu of this, we would like to employ a semi-active augmentation approach (by addition of springs and dampers). Such an approach serves to redirect power (motions and forces) to achieve the desired functional outcomes from the knee braces. However, the suitable selection of geometric dimensions of the brace and spring parameters to achieve desired motion- and force-profiles at the knee remains a challenge. We therefore introduce a two-stage kinetostatic design process to help customize the brace to match a desired kinematic/static performance.
Fractional Order Sliding Mode Control Based on Fractional Order Reaching Law: Reaching Condition Analysis and Experimental Validation
Authors: Yin Chun , Li Zhuo , Chen YangQuan , Zhong Shou-ming
Published: February 2014

In this paper, a novel fractional order (FO) reaching law with an FO sign function is proposed. It is used to guarantee the the occurrence of reaching phase in finite time. Since the traditional integer order (IO) reaching law can be considered as a special case of the FO reaching law, it is more likely for the FO reaching law to obtain better performance. The properties of the FO sign function are used to prove the capability of states to approach the switching manifolds. Compared with the IO sign function in the classical reaching law, the states reach the switching manifolds faster with the FO reaching law. It will be shown that the reaching time under the FO SMC can be reduced by analyzing the FO sign function under appropriate conditions. Moreover, the sliding dynamics can arrive at the equilibrium point more rapidly by applying the FO reaching law. Simulation results including comparisons between the FO SMC and the IO SMC are presented to illustrate the advantages of the proposed scheme. Finally, a fractional horsepower dynamometer is utilized as a real time simulation platform to demonstrate the effectiveness of the proposed FO reaching law.
A Strength Based Approach for the Synthesis of a Compliant Nonlinear Spring for an Orthotic Knee Brace
Authors: Krishnan Girish , Rank Ryan , Rokosz John , Carvey Phil , Kota Sridhar
Published: February 2014

Lightweight mechanical energy-storage devices or springs with nonlinear strain-energy absorption rate are important building blocks for passive/quasi-passive rehabilitation robotics. They provide support and controllable energy storage/release into the system thereby making daily activities such as walking/running metabolically efficient for the disabled. These devices have stringent footprint constraints and must withstand 10 million cycles of loading for successful implementation on an orthotic device. Currently, there are no off-the-shelf springs or a systematic synthesis methodology that can meet these requirements in a deterministic fashion. In this paper, we demonstrate how existing body of knowledge in compliant mechanisms can be systematically leveraged to design spring geometries with distributed compliance that meet fatigue criteria and weight requirements. Towards this, we implement a strength-based approach to determine feasible initial solutions that upon optimization yield geometries with maximally distributed stresses. Such a framework is general and can be adapted for designing any compliant mechanism.
Modeling and Estimation of Energy Usage for Double Skin Facades Buildings
Authors: Abou-Nassar Guy , Siddique Zahed
Published: February 2014

In a time when energy crises loom on the horizon, means for more efficient energy sources are being thoroughly researched. One such area for improvement is in the building sector with the implementation of double skin façades (DSF). With capabilities of relatively rapid and large changes in various aspects of itself, a DSF can respond dynamically to varying ambient conditions. Applying American Society of Heating, Refrigerating and Air-Condition Engineers, Inc (ASHRAE) standards to design a general building model with a standard HVAC system, a comparison can be drawn between different architectural configurations, both with and without DSFs, and a better understanding of how a DSF can affect heat transfer into a building could potentially influence future structural design decisions. Using CAD models, a flow analysis and rudimentary heat transfer can be conducted in a computational fluid dynamics (CFD) software, Fluent which can account factors such as wind speed as well as solar radiation. With the various design applications, the heat load of a building can be reduced by over 15%.
Solving Interval Master Equation in Simulation of Jump Processes Under Uncertainties
Authors: Wang Yan
Published: February 2014

Two types of uncertainty are generally recognized in modeling and simulation, including variability caused by inherent randomness and incertitude due to the lack of perfect knowledge. Generalized interval probability is able to model both uncertainty components simultaneously, where epistemic uncertainty is quantified by the generalized interval in addition to the probabilistic measure. With the conditioning, independence, and Markovian property uniquely defined, the calculus structures in generalized interval probability resembles those in the classical probability theory. An imprecise Markov chain model is proposed with the ease of computation. A Krylov subspace projection method is developed to solve the interval master equation to simulate jump processes with finite state transitions under uncertainties. The state transitions with interval-valued probabilities can be simulated, which provides the lower and upper bound information of evolving distributions as an alternative to the traditional sensitivity analysis.
Hardness Detection Sensor for Cubic Nonlinear Elasticity Using Nonlinear Self-Excited Oscillation
Authors: Kokubun Yosuke , Yabuno Hiroshi , Kuroda Masaharu , Yamamoto Yasuyuki
Published: February 2014

This paper proposes a measurement method of cubic non-linear elasticity. The measurement system consists of a vibrator and a control circuit. We apply a nonlinear feedback to actuate the vibrator for inducing van der Pol type self-excited oscillation, so that the response amplitude of the oscillation can be arbitrarily set by changing the nonlinear feedback gain. We focus on the fact that the nonlinear elasticity causes a natural frequency shift related to the vibration amplitude of the object. We can set the response amplitude various values by changing the nonlinear feedback gain and measure the shift of the response frequency depending on the magnitude of the response amplitude. As a result, the bend of the backbone curve reflecting the nonlinear elasticity of the object is obtained.
Dynamic Analysis of a Multi-Mesh Gear System With Mesh Stiffness Variation
Authors: Jiang Hanjun , Shao Yimin
Published: February 2014

Parameter excited oscillations induced by the varying tooth mesh stiffnesses of the gear pairs cause severe vibration in gear systems. The oscillations become more complex and serious in multi-mesh gear system because more mesh stiffnesses variation occur, which are necessary to be investigated in deeply. To illustrate the complex oscillation phenomena, a 8 degrees of freedom (DOF) non-linear dynamic model of a multi-mesh gear system is developed to study the responses of the system with considering time-varying mesh stiffnesses. Interactions between the mesh stiffness variations at the two meshes are examined. Seven different mesh phases are defined according to the alternating engagement of single and double gear teeth. The effects of different phases of the mesh stiffnesses between the two meshes on the typical multi-mesh gear system are identified by using numerical simulation. The results show that the oscillations of the multi-mesh gear system could be reduced by changing the phase of the mesh stiffnesses.
Identification of the Dynamic Behavior of Surrogate Explosive Materials
Authors: Paripovic Jelena , Davies Patricia
Published: February 2014

Improvised explosive devices are often made to resemble objects that are a natural part of the environment. It is hypothesized that by understanding the mechanical behavior of the explosive material it may be possible to tune an acoustic excitation to produce signatures that indicate explosives are present in an object. Here the focus is on identification of mechanical material properties and their effect on a system’s dynamic response. Energetic material surrogates were produced by embedding inert crystals within the binder. Swept-sine wave base-excitation tests were conducted to examine repeatability of the material-mass system responses. Compression test data were fitted using a two-term Ogden model but for a massmaterial base-excited system a continuous-time system identification method was used to estimate model parameters. Damping ratios of 0.11 for the 0% (no crystals) material and 0.19 for the 50% (crystal volume fraction) material were estimated. Future work includes examination of models that include a hereditary model of viscoelasticity and nonlinear terms, and experimental investigations at higher forcing levels.
Closed-Form Optimization of Resonant Shunted Electromagnetic Tuned Mass Dampers for Vibration Control and Energy Harvesting
Authors: Tang Xiudong , Cui Wen , Zuo Lei
Published: February 2014

This paper investigated the electromagnetic shunted TMD, which consisted of a single degree-of-freedom (DOF) primary mechanical system, an electromagnetic transducer and a resonant circuit. It can provide similar vibration mitigation performance as the traditional TMD system without introducing additional mass. The analytical solutions to the optimal parameters are obtained using both H2 and H∞ optimization criteria. The optimal parameters are summarized in a closed form, which can be useful for practical implementation. The sensitivity analysis carried out in this paper also suggested that the vibration mitigation performance is not sensitive to the damping ratio namely the resistance of the circuit, while it is very sensitive to the frequency off tuning namely the capacitance or inductor of the circuit. Besides, this paper also investigated the parameter optimization for energy harvesting using the electromagnetic shunted resonant circuit. It is found that the power is independent of the parameters under white noise force disturbance, in a similar way as the finding on the dual-mass vibration energy harvester. The resonant circuit can also enhance the maximum energy harvesting rate.
Design Method for Optimizing Contact Ratio of Hypoid Gears
Authors: Miyamura Hiromi , Shibata Yoshikatsu , Inagaki Mizuho , Aoyama Takayuki
Published: February 2014

Innumerable solutions can be obtained when the pitch surface of a hypoid gear is solved from the requirements of two cones. The pitch angle is determined by the Gleason method based on the idea that the tooth lengthwise curvature corresponds to the cutter radius. This study proposes a new design method that can optimize the contact ratio using the pitch angle, using the new tooth geometry advocated by Honda. The balance of the contact ratios of the convex and concave sides of a gear can be optimized by designing the pitch angle. By optimizing the contact ratio, noise and vibration performance can be improved. In addition, highly efficient gear design can be achieved by decreasing the spiral angle.

The effectiveness of this optimized design method is confirmed by measuring transmission errors under load. Design examples of a highly efficient gear by reducing the spiral angle and a gear which ensures high noise and vibration performance are shown. Using this proposed method expands the design freedom of hypoid gears.
Business Domain Decision Method for Manufacturing and Service
Authors: Onda Hiroomi , Miwa Toshiharu , Jackson Vincent R. , Park Dahwe , Reynolds Kevin W. , Beiter Kurt A.
Published: February 2014

This paper deals with a study on a method to support the decision on entering business areas in a business model consisting of manufacturing and service. This method divides the business model into business areas by the functions that support a company to decide whether it should enter business areas.

This method prioritizes the areas from the aspects of profit opportunities, barriers to entry, and interactions between the areas. This method reduces the time to decide which business area to enter and reduces the number of examination objects to the number of business areas (n) or fewer from the total number of possible combinations (2 to the 2nd power n).

To confirm the efficiency of this method, we demonstrated two case studies in the IT services industry. In the first case study, from the perspective of a UPS battery supplier, the number of examination objects is 3 when the number of business areas is 11. And the first case study indicates that a suitable strategy for a battery supplier is to concentrate on the strategy of supplying batteries. In the second case study, from the perspective of an IT service provider, the number of examination objects is 10 when the number of business areas is 11. The second case study indicates that a suitable strategy for an IT service provider is vertical integration from software development to data center operation and hardware manufacturing.
Interactive Thermo-Fluid Simulation by Using Reduced Order Models
Authors: Kobayashi Sachio , Kobayashi Hiroki , Ikeda Hiroshi , Hashima Masayoshi , Sato Yuichi
Published: February 2014

We present a new finite difference-based thermo-fluid simulation method by using reduced order models. Reduced order modeling technique is to project a high dimensional problem onto a lower dimensional subspace and then solve the problem in the reduced subspace. We solve the incompressible Navier-Stokes equations and the heat equation in their respective subspaces and join the two equations by projecting the advection term onto the joint reduced space. Our algorithm allows for fast thermo-fluid simulation of the large-scale computational models at a fraction of computational load. Our method shows more than one thousand times faster speed than usual mesh-based fluid simulation, while maintaining acceptable engineering accuracy. The real-time feature of our method enables interactive user interfaces for, e.g., assessing an immediate thermal field change in response to consecutive control of air-conditioning equipment in a data center.
Force-Position Hybrid Control of a New Parallel Hexapod Robot for Drilling Holes on Fuselage Surface
Authors: Zhao Xianchao , Pan Yang , Gao Feng
Published: February 2014

In this paper, a new kind of 6-legged robot for drilling holes on the aircraft surface is presented. Each leg of the robot is a parallel mechanism with 3 degree of freedoms thus the robot includes totally 18 motors. Due to different work status, the control modes of these motors are also different and thus the force-position hybrid control method is applied. The kinematic and dynamic model is briefly introduced. Then the robot gait is discussed. After that hybrid control method is introduced: first the control mode of each motor should be determined, then the position or force control curves should be calculated. In the end of this paper, both virtual and real prototype of this robot is showed and the experiment result showed that the hybrid control method can significantly improve the robot performance.
Incremental Inspection for Microrobotic Quality Assurance
Authors: Christensen David L. , Hawkes Elliot W. , Wong-Foy Annjoe , Pelrine Ronald E. , Cutkosky Mark R.
Published: February 2014

This paper addresses inspection techniques that can be performed by microrobots used for fabricating three dimensional structures. In contrast to most commercial rapid prototyping processes, the parallelism afforded by microrobot teams allows incremental inspection of structures during assembly. In the present case, this approach is applied to parts fabricated from carbon fiber struts bonded with UV-cured epoxy. Preliminary tests involving thermal and vibrational inspection methods are described and compared with the results of FEA models of the joints. Vibrational inspection performed by microrobots and recorded using a directional microphone, characterizes bond joint natural frequency with good resolution (an average measurement standard deviation of 5Hz over a range of 650–1215 Hz). These effective stiffness measurements are correlated with ultimate bond strength as well. The measurements are sufficient to distinguish between joints that do or do not have desired amounts of adhesive.
An Improved Maximum Power Point Tracking Based on Fractional Order Extremum Seeking Control in Grid-Connected Photovoltaic (PV) Systems
Authors: Malek Hadi , Dadras Sara , Chen YangQuan
Published: February 2014

This paper presents a fractional order extremum seeking control scheme for grid-connected photovoltaic (PV) systems tasks to better accommodate rapid varying solar irradiance for photovoltaic (PV) arrays. The stability analysis of the proposed control algorithm is presented first. Then the new algorithm is benchmarked against the integer order extremum seeking control. Our extensive simulation and experimental results show that, our proposed maximum power point tracker has faster convergence speed in comparison to integer order and incremental conductance algorithm and also less total harmonic distortion (THD) in the injected current to the grid.
Sliding Window POD Analysis of Vibrating Structures: Application to Nonlinear Forced Structure Under Axial Flow
Authors: Clément Simon , Bellizzi Sergio , Cochelin Bruno , Ricciardi Guillaume
Published: February 2014

In this paper, a multivariate data analysis method combining the Proper Orthogonal Decomposition (POD) and a time-frequency analysis (TEA) is presented. The POD method is a tool adapted to the study of multi-degrees of freedom systems, which can give some insight of the behavior of complex nonlinear systems, whereas TEA is suitable for scalar signal with multi-frequency components. The method presented here is of principal interest in the case of swept-sine excitation of complex multi-DOF systems. It will be first applied to a synthetic signal, then mechanical simulations and finally experimental results.
Application of Cyclostationary Indicators for the Diagnostics of Distributed Faults in Ball Bearings
Authors: D’Elia Gianluca , Delvecchio Simone , Cocconcelli Marco , Dalpiaz Giorgio
Published: February 2014

This paper deals with the detection of distributed faults in ball bearings. In literature most of the authors focus their attention on the detection of incipient localized defects. In that case classical techniques (i.e. statistical parameters, envelope analysis) are robust in recognizing the presence of the fault and its characteristic frequency. In this paper the authors focalize their attention on bearings affected by distributed faults, due to the progressive growing of surface wear or to low-quality manufacturing process. These faults can not be detected by classical techniques; in fact, in this case the signal does not contain impulses at the fault characteristic frequency, but more complex components with strong non-stationary contents. Distributed faults are here detected by means of advanced tools directly derived from the theory of cyclostationarity. In particular three metrics — namely Integrated Cyclic Coherence (ICC), Integrated Cyclic Modulation Coherence (ICMC) and Indicator of Second-Order Cyclostationarity (ICS2x) — have been calculated in order to condense the information given by the cyclostationary analysis and to help the analyst in detecting the fault in a fast fault diagnosis procedure. These indicators are applied on actual signals captured on a test rig where a degreased bearing running under radial load developed accelerated wear. The results indicated that all the three cyclostationary indicators are able to detect both the appearance of a localized fault and its development in a distributed fault, whilst the usual approach fails as the fault grows.
Incoming Stall Identification in Axial Compressors by Vibration Analysis
Authors: D’Elia Gianluca , Dalpiaz Giorgio
Published: February 2014

This work addresses on a complete vibro-acoustic characterization of an axial compressor with the aim to foresee the rotor instability. The tests were performed on a turboshaft Allison 250-C18. The compressor is composed of six axial stages and one centrifugal stage. Four vibration signals were simultaneously measured by means of accelerometers, while the acoustic signals were measured by means of two microphones. Two different kinds of tests have been carried out on the compressor that operates at constant speed: in the course of the first test the six signals were acquired at different positions of the throttle opening, whereas during the second test, the signals were acquired while the throttle was gradually opened. The test results show a sensitive increase of the sub-synchronous activity in the accelerometers spectrum map, moreover, closing the throttle, the amplitude of the spectrum components increases. These phenomena can be related to the rotating stall behavior.
Experimental Investigation With Wireless Sensors of the Nonlinear Interaction Between Rotational Motions and Torsional Vibrations in a Coupled Rigid Rotor-Flexible Rotor System
Authors: Georgiou Ioannis T.
Published: February 2014

This work presents an experimental study focused on a challenging signal interpretation issue arising in using wireless tri-axial sensors to measure acceleration components in rotating flexible rotor systems. Experiments with state of-the-art (modern technology microsystems) wireless accelerometers reveal that the dynamics of a rotating and-at the same time torsionally vibrating-flexible rotor system is perceived by the rotating sensor as a fast amplitude modulation of a slowly varying vibration. It is observed that the typical signal furnished by the rotating sensor consists of two distinct zones of harmonics: one is a broad band low frequency zone and is associated with the rigid body rotational motion, whereas the other zone contains distinct higher frequencies associated with torsional vibrations. The interesting result is the fact that in the frequency domain the fast torsional vibrations can be extracted sharply from the overall sensor signal. This is due to fact that the dynamics of the sensor output are characterized by slow and fast time scales. It turns out that the high harmonics of the rotating-and-vibrating system (generic motion) are very close to those of the non-rotating-but-torsionally vibrating system. A definite answer to a physics interpretation of the typical output of a rotating accelerometer (oscillator-based) is established by modeling the whole flexible rotor-sensor system as a singular perturbation coupled oscillators problem. This geometric mechanics modeling-analysis approach presents a global picture of the acceleration sensing property of stiff linear oscillators attached on rotating structures.
Variation Simulation of Stresses Using the Method of Influence Coefficients
Authors: Lorin Samuel , Lindkvist Lars , Söderberg Rikard
Published: February 2014

In every manufacturing situation there are geometric deviations leading to variation in properties of the manufactured products. Variation affects the manufacturability, functions and aesthetics of the products. Therefore, a number of methods and tools have been developed during the last 20 years in order to assure the geometric quality and to minimize the effect of variability. These methods and tools have mainly been developed for rigid bodies or sheet metal components.

Plastics or composites have been an increasingly popular material due to their flexible mechanical properties and their relative ease in manufacturing. However, their mechanical properties are introducing challenges that have not often been addressed in the process of geometry assurance. One challenge is to assure that the stresses introduced, as a consequence of non-nominal assembly in the positioning system, are kept well below critical limits during the conditions of use.

In this paper, we are proposing the use of the method of influencing coefficients (MIC) to simulate the distribution of von Mises stresses in assembled components. This method will be compared to the more flexible but computationally much heavier Direct Monte Carlo (DMC) method, which is not suitable for variation simulation due to the large number of runs required for statistical inference.

Two industrial case studies are presented to elicit the need of the proposed method.
Parameters Identification Strategy for a Generalized Vehicle Concept Model for Ride and Handling Analysis
Authors: Carpinelli Mariano , Gubitosa Marco , Mundo Domenico , Desmet Wim
Published: February 2014

In this paper we propose a structured approach for the parameters identification of a multibody vehicle concept model to be used for the combined analysis of vertical and longitudinal dynamics. The model here proposed adopts eight degrees of freedom in the space. The wheels are connected to the sprung mass in an equivalent trailing arm configuration thus enabling to reproduce the squat and dive phenomena. This conceptual suspension representation allows determining the dynamic response of the vehicle during longitudinal acceleration or braking maneuvers. The identification procedure here suggested evaluates the unknown parameters of the model, being the global stiffness and damping coefficients of the suspensions and the positions of the pivot points of the trailing arms. The identification algorithm is based on non-linear least square costs that can be computed by having as reference the signals of a measurement campaign which is conducted on a real vehicle as well as on a virtual predecessor model. The results here shown make use of virtually measured quantities coming from ride maneuvers performed by means of a high fidelity multibody model of a passenger car. The presented concept model, showing good correlation with respect to the reference signals, is suggested as a reliable prediction and optimization tool in the early stage of the design phase of new vehicles.
Lyapunov Stability of Linear Fractional Systems: Part 1 — Definition of Fractional Energy
Authors: Trigeassou Jean-Claude , Maamri Nezha , Oustaloup Alain
Published: February 2014

This paper addresses the stability of linear commensurate order fractional systems, Dn (X) = AX 0 < n < 1, using the infinite state approach. First, the energy of a fractional integrator is defined, using the distributed energy of its initial state. Compared to the integer order case, this energy is characterized by a long memory decay, which is the characteristic feature of fractional systems. Then, it is applied to define the energy V(t) of a one derivative system. Numerical simulations exhibit the influence of initial conditions on V(t). Thanks to the definition of a dissipation function, a stability condition is derived. Finally, the general case is investigated and a weighted Lyapunov function is derived, using a positive P matrix, related to the eigenvalues of A matrix.
Investigation of Dry Friction Effect of Shroud Damping Wire on Model Test Bladed Wheel
Authors: Pesek Ludek , Pust Ladislav , Bula Vitezslav , Vanek Frantisek , Cibulka Jan
Published: February 2014

This paper presents the numerical and experimental solutions of inter-slip damping of the shroud wire of the test bladed disk. The numerical approach is based on a space finite element model which presents ten blades connected by the wire in their heads. The couplings are considered to be surface-to-surface contacts with friction. The damping effect is evaluated from the free attenuation after a resonant vibration. The resonant vibration of the blades was excited by synchronic pulses of a electromagnets during the experiment. The responses of the blades were measured by strain-gauges with a slip-ring signal transmission at rotation. The calculated damping ratios of dynamic responses of the bladed wheel are in a good accordance with the experimental results.