bluuebunny/crossref_metadata_2025 huggingface dataset:
Design for Fused Filament Fabrication Additive Manufacturing
Authors: Steuben John , Van Bossuyt Douglas L. , Turner Cameron
Published: January 2016

In this paper, we explore the topic of Fused Filament Fabrication (FFF) 3D-printing. This is a low-cost additive manufacturing technology which is typically embodied in consumer-grade desktop 3D printers capable of producing useful parts, structures, and mechanical assemblies. The primary goal of our investigation is to produce an understanding of this process which can be employed to produce high-quality, functional engineered parts and prototypes. By developing this understanding, we create a resource which may be turned to by both researchers in the field of manufacturing science, and industrial professionals who are either considering the use of FFF-enabled technologies such as 3D printing, or those who have already entered production and are optimizing their fabrication process. In order to paint a cohesive picture for these readers, we examine several topic areas. We begin with an overview of the FFF process, its key hardware and software components, and the interrelationships between these components and the designer. With this basis, we then proceed to outline a set of design principles which facilitate the production of high quality printed parts, and discuss the selection of appropriate materials. Following naturally from this, we turn to the question of feedstock materials for FFF, and give advice for their selection and use. We then turn to the subject of the as-printed properties of FFF parts and the strong non-isotropic response that they exhibit. We discuss the root causes of this behavior and means by which its deleterious effects may be mitigated. We conclude by discussing a mixed numerical/experimental technique which we believe will enable the accurate characterization of FFF parts and structures, and greatly enhance the utility of this additive manufacturing technology. By formalizing and discussing these topics, we hope to motivate and enable the serious use of low-cost FFF 3D printing for both research and industrial applications.
A Comparative Experimental Evaluation of IMU Designs
Authors: Ravani Bahram , Sherrett Jason L. , Lasky Ty A.
Published: January 2016

This paper presents the design of an experimental platform for rapid prototyping, testing, evaluation, and validation of different sensor types and configurations for Inertial Measurement Unit (IMU) applications. Two example IMU designs are rapidly prototyped and tested on this experimental platform. The first design was based on a triad of gyroscopes, three dual-axis accelerometers and a triad of magnetometers to provide information on the Earth’s magnetic field for the purpose of bounding the attitude drift. The second system was based on twelve accelerometers and again a triad of magnetometers. An Unscented Kalman Filtering technique is used to fuse the IMU and magnetometer data in both cases for an Inertial Navigation System (INS). Test results are presented comparing the two IMU designs to each other and to ground truth with minimal magnetic interference and with introduction of deliberate magnetic interference. The results indicate that the two systems have excellent performance for high-speed applications, while at lower speeds the first design outperforms the second design. It is also shown that external magnetic disturbance degrades the performance of both designs.
Robotic Physical Exercise and System (ROPES): A Cable-Driven Robotic Rehabilitation System for Lower-Extremity Motor Therapy
Authors: Alamdari Aliakbar , Krovi Venkat
Published: January 2016

Assisted motor therapies play a critical role in enhancing the functional musculoskeletal recovery and neurological rehabilitation. Our focus here is to assist the performance of repetitive motor-therapy of the human lower limbs — in both the sagittal and frontal planes. Hence, in this paper, we develop a lightweight, reconfigurable hybrid (articulated-multibody and cable) based robotic rehabilitative device as a surrogate for a human physiotherapists and analyze feasibility and performance. A hybrid cable-actuated articulated multibody system is formed when multiple cables are attached from a ground-frame to various locations on the lower limbs. The combined system now features multiple holonomic cable-loop-closure constraints acting on a tree-structured multibody system. Hence the paper initially focuses on developing the Newton-Euler dynamic equilibrium equations of the cable-driven lower limbs to develop a symbolic analysis framework. The desired motion for the proposed rehabilitative exercise are prescribed based upon normative subjects motion patterns. Trajectory-tracking within this system is realized by a position-based impedance controller in task-space and a feedback-linearized PD controllers in joint-space. Careful coordination of the multiple cable-motors are now necessary in order to achieve the co-robotic control of the overall system, avoiding development of internal stresses and ensuring continued satisfaction of the unilateral cable-tension constraints throughout the workspace. This is now evaluated via a simulation case-study and development of a physical testbed is underway.
Nonlinear Vibration Absorber Design: An Asymptotic Approach
Authors: Casalotti Arnaldo , Lacarbonara Walter
Published: January 2016

The one-to-one internal resonance occurring in a two-degree-of-freedom (2DOF) system composed by a damped non-linear primary structure coupled with a nonlinear vibration absorber is studied via the method of multiple scales up to higher order (i.e., the first nonlinear order beyond the internal/external resonances). The periodic response predicted by the asymptotic approach is in good agreement with the numerical results obtained via continuation of the periodic solution of the equations of motion. The asymptotic procedure lends itself to manageable sensitivity analyses and thus to versatile optimization by which different optimal tuning criteria for the vibration absorber can possibly be found in semi-closed form.
My Idea Is Best! Ownership Bias and its Influence on Engineering Concept Selection
Authors: Toh Christine A. , Patel Arti H. , Strohmetz Andrew A. , Miller Scarlett R.
Published: January 2016

Concept selection is considered one of the most crucial components of the engineering design process because the direction of the final design is largely determined at this stage. One of the most widely utilized techniques for filtering designs during this process involves informal review meetings where team members identify the designs that most closely satisfy the design goals. While this is often seen as an efficient process, factors such as ownership bias, or an unintentional preference for an individuals’ own ideas, and team member personality attributes may impact an individual’s decision-making process. However, few studies have explored the impact of these factors on concept selection. Therefore, an empirical study was conducted with 37 engineering students in order to investigate the effect of these attributes on the selection or filtering of design concepts in engineering education. The results from this study show that personality impacts the proportion of ideas selected, and that male students tend to select more of their own ideas (ownership bias) than their female counterparts who more often select their team member’s concepts. These results add to our understanding of the factors that impact the team concept selection process and provide empirical evidence of the occurrence of ownership bias in engineering design education.
Patterns of Creative Design: Predicting Ideation From Problem Formulation
Authors: Dinar Mahmoud , Park Yong-Seok , Shah Jami J. , Langley Pat
Published: January 2016

The main objective of our research is to understand the role of problem formulation in creative design ideation. To that end, we have used the web-based testbed of the Problem Map (P-map) computational framework which represents designers’ problem formulation in terms of a series of state models, where each state consists of six types of entities in addition to relations within and between different entity types. We gave two design problems to twenty five graduate students in an advanced product design course. We collected their problem formulation data in the P-map testbed and their ideation data through concept sketches. We conducted correlation analysis between variables extracted from the P-maps, and the ideation metrics. We also built regression models for each of the ideation metrics as the dependent variable, and the P-map variables as the independent variables. We used the data from the first problem to predict the ideation scores for the second problem. The predicted results were compared to the actual outcome reported by an independent panel of judges. Models of variety, average and max quality had more accurate predictions while average novelty, average and max quality had statistically more reliable models.
Integrating Design Methodology, Thermal Sciences, and Customer Needs to Address Challenges in the Hair Care Industry
Authors: Hahn Jaesik , Dandridge Tikyna , Seshadri Priya , Marconnet Amy , Reid Tahira
Published: January 2016

Although the hair care industry is a multi-billion dollar industry, there still remains a dearth in the available technologies and research methods to answer one simple question: What temperature and frequency of use will lead to permanent structural damage (i.e. heat damage) to curly hair? Currently, trained professionals in the hair industry cannot predict when heat damage will occur and often rely on heuristics and intuition in their hair care approaches. In addition, scientists that have conducted studies with heat and hair have often used European hair types, which cannot be generalized to all ethnic groups; they have also conducted experiments that are not ecologically consistent with individuals’ use context. As a result, a number of lay scientists have emerged whose use contexts are ecologically valid, but are lacking the experimental and quantitative rigor that engineers can provide. In this work, we discuss an interdisciplinary approach to integrating customer needs, design methodology, and thermal sciences for application to the hair care industry. We discuss the formulation of a predictive model, the design of an experimental test-bed for collecting data, and present initial results.
A Novel Capacitive Sensing Principle for Microdevices
Authors: Zhou Jian , Miles Ronald N. , Towfighian Shahrzad
Published: January 2016

Conventional capacitive sensing places significant limitations on the sensor design due to the pull-in instability caused by the electrostatic force. The main purpose of this study is to examine a low-cost novel capacitive sensing principle based on electrostatic balance which promises to avoid these design limitations. The approach uses an asymmetric electric field on a structure with fingers that can generate a repulsive force while the gap is low and create an attractive force while the gap is large. The size and thickness of the fingers are also responsible for creating repulsive or attractive forces on the structure. This approach has recently been applied successfully in the design of capacitive actuators to provide a repulsive driving force. A new design principle for capacitive sensing is described that avoids pull-in instability by designing the fingers such that the structure is at the equilibrium.
A Method for Designing Flat-Foldable 3D Polygonal Models
Authors: Kase Yuto , Kanamori Yoshihiro , Mitani Jun
Published: January 2016

We propose a method for designing targeted 3D polygonal models that can be folded flat, which consist of side panels as well as horizontal top and bottom panels. Vertically adjacent panels are connected by hinges at their horizontal edges. The models can be folded flat by pushing down the top panel, while they can be also deployed by pulling up the top panel. The key idea in making the model so that it can be folded flat is to add vertical slits along the edges of side panels; the horizontally adjacent side panels are separated in the folded state, and are connected to form a closed solid model in the deployed state. Our method takes the shapes of the top panel as well as the cross sections of the side panels as inputs. Users of our prototype system first simply draw the top panel as a convex polygon. They then draw polylines to specify the cross sections. Since the polyhedral model generated by the input data rarely satisfies flat-foldability conditions, our system modifies the positions of the vertices in cross sections based on numerical optimization. Unlike most origami design systems that ignore material thickness, our system can output the 3D geometry of panels so that they can be used to form a closed 3D model with a certain thickness.
Gear and Bearing Failure Detection Using Vibration Monitoring and Mahalanobis-Taguchi System
Authors: Koide Takao , Matsuura Daisuke , Tamura Atsutaka , Yasugi Takuya , Mori Takashi
Published: January 2016

Vibration monitoring is used to detect a failure in gear systems. An approach in this paper uses Mahalanobis-Taguchi System (MTS) along with vibration monitoring to improve a sensitivity of failure detection. Running tests were conducted by using a power-circulating-type gear test machine. Gear and bearing failures were examined. The Mahalanobis distance was calculated by using measured vibration acceleration data during the running tests. Relations between the Mahalanobis distance and the initiation and propagation of the gear failures or the bearing failures were discussed. The results show that the Mahalanobis distance is an effective indicator of the gear and bearing failures.
BPM: A Bad Page Management Strategy for the Lifetime Extension of Flash Memory
Authors: Debao Wei , Liyan Qiao , Peng Zhang , Xiyuan Peng
Published: January 2016

The lifetime of NAND flash is highly restricted by bit error rate (BER) which would exponentially increase with the number of program/erase cycles. While the error correcting codes (ECC) can only provide a limited error correction ability to tolerate the bit errors. To face this challenge, a novel bad page management (BPM) strategy is proposed to extend the lifetime of NAND flash based on the experimental observations in our hardware-software co-designed experimental platform. The experimental observations indicate that retention error is the dominant type of NAND flash errors, which is caused by the charge leakage in memory cells over time. The BER distribution of retention error shows distinct variance in different pages. The key idea of BPM is to excavate lifetime potency of each page in a block by introducing the fine granularity bad page management instead of the coarse granularity bad block management. In addition, to balance the lifetime enhancement and the storage capacity degradation, a configurable threshold of bad page management (CT-BPM) strategy is proposed to utilize in the storage capacity highly demanded applications. The experimental results show that BPM can provide dozens of times (about 35 times for 3x-nm NAND flash) average lifetime extension without additional hardware cost, while experiencing at most 5% degradation in writing speed.
Sequential Multidisciplinary Design Optimization and Reliability Analysis Using an Efficient Third-Moment Saddlepoint Approximation Method
Authors: Meng Debiao , Huang Hong-Zhong , Xu Huanwei , Zhang Xiaoling , Li Yan-Feng
Published: January 2016

In Reliability based Multidisciplinary Design and Optimization (RBMDO), saddlepoint approximation has been utilized to improve reliability evaluation accuracy while sustaining high efficiency. However, it requires that not only involved random variables should be tractable; but also a saddlepoint can be obtained easily by solving the so-called saddlepoint equation. In practical engineering, a random variable may be intractable; or it is difficult to solve a highly nonlinear saddlepoint equation with complicated Cumulant Generating Function (CGF). To deal with these challenges, an efficient RBMDO method using Third-Moment Saddlepoint Approximation (TMSA) is proposed in this study. TMSA can construct a concise CGF using the first three statistical moments of a limit state function easily, and then express the probability density function and cumulative distribution function of the limit state function approximately using this concise CGF. To further improve the efficiency of RBMDO, a sequential optimization and reliability analysis strategy is also utilized and a formula of RBMDO using TMSA within the framework of SORA is proposed. Two examples are given to show the effectiveness of the proposed method.
Haptic Interface of Data-Drone Operation Considering Human Operator’s Force Sensitivity
Authors: Irannejad Niloufar , Chen YangQuan , Huang Jiacai
Published: January 2016

Lots of drone crashes happen when the operator goes out of the control loop. In drone controlling scenarios, exerting force feedback to the operator keeps the human in the loop and improves the performance of the operation. Thus, having the required knowledge about human force sensitivities will have a great influence on applying the proper amount of force-feedback to the operator. One of the important human factors is the so-called “just noticeable difference” (JND) that describes the minimum noticeable difference for any stimulus, which has been investigated in the literature.

The goal of this study is to utilize the results of previous researches on extracting force JND values for human wrist and shoulder, use them in a drone control scenario to present the effects of these factors. Even though the final goal of this project is to control a drone in the real world situation, we focus on a simulated case with 1 DoF. We create a virtual environment that a drone can be controlled with a 1 DoF haptic device. Any change in the drone state will be reflected as a force change on the haptic interface that is applied to the operator. We calculate the force change in different ways, and report the influences on the control performance.
The Adjoint Systems of Time Fractional Diffusion Equations and Their Applications in Controllability Analysis
Authors: Ge Fudong , Chen YangQuan , Kou Chunhai
Published: January 2016

This paper is devoted to the construction of the adjoint system for the case of time fractional order diffusion equations. We first obtain the equivalent integral equation of the abstract fractional state-space system of both Caputo and Riemann-Liouville type by utilizing the Laplace transform and the semigroup theory. Then the adjoint system of time fractional diffusion equation is introduced and used to analyze the duality relationship between observation and control in a Hilbert space. The new introduced notations can also be used in many fields of modelling and control of real dynamic systems.
Determination of Power and Torque Curves of Electric Driven Vehicles Based on Diagnostic Methods
Authors: Lakatos István , Pup Dániel , Czeglédi Dávid
Published: January 2016

The transmitted power of motors can be defined by test bench examinations, in which the motor needs to be dismounted. By applying diagnostic methods only minimal disassembly, or indeed none at all, is necessary. In this paper diagnostic methods are systematized by different studies. Moreover, a new diagnostic procedure (established by the authors) is also introduced, which can be carried out by a relatively cheap measuring system design.

Power measurement on a roller test bench is a well-tried technique for vehicle examination. Basically, the wheel parameters (tractive force, torque, power) are measured, but there are also procedures for motor power measurement. By applying the new procedure, the diagnostic method, (simple construction and test bench construction at a favourable price) torque and power characteristics of the mounted motor can be defined. The theoretical considerations of the new measuring technique and the implementation of the measuring system are introduced in this paper.

Test bench for drive motor power and torque curve determination.

In this study the diagnostical measuring systems and, for the first time, the measuring principle and technology of the new theory-based roller power test bench are presented. For its construction measurements have been carried out which make an important contribution to the research.

The results of the research contribute to the development of diagnostics methods and to making them more wide-spread.
Development of Pairing Performance Tester for Vehicles Cylindrical Gears
Authors: Shu Zanhui , Shi Zhaoyao , Wang Xiaoyi , He Fayang , Chen Hongfang
Published: January 2016

So far, researches of the meshing performance of vehicles cylindrical gears are quite rare. Testers that can be used to test the gear pair’s performance for vehicles cylindrical gears do not exist. A tester that can be used to test vehicles cylindrical gears paring performance was developed, which fills the gaps of vehicles cylindrical gears meshing performance tester. The maximum diameter of gears measured is 500mm, the maximum spindle speed is 3000r/min and the maximum load torque is 200N.m. The tester can inspect and measure the following items simultaneously, such as the transmission errors, the vibration and noise, the contact pattern, the eccentricity errors and so on. There is gear error analysis function in this tester. In addition, it can meet the quality inspection requirements for the vehicles cylindrical gears with the accuracy of grade 5.
An Agent-Based System to Simulate Dynamic and Noisy Ambience of Industrial Wireless Sensor Networks
Authors: Gholami Mohammad , Brennan Robert W.
Published: January 2016

In this paper, we propose a multi-agent systems approach for wireless sensor node tracking in an industrial environment. The research builds on extant work on wireless sensor node clustering by reporting on the development of a set of simulation models to support our distributed management approach for tracking mobile nodes in a large-scale industrial wireless sensor network. Our simulation models build on models and concepts from the literature on wireless sensor networks and wireless communication, with adaptations to address the needs of an industrial environment. An example of mobile node tracking with our distributed management approach is presented, showing accurate tracking performance for both fixed and random mobile node paths.
Inverse Kinematics of Discretely Actuated Ball-Joint Manipulators Using Workspace Density
Authors: Dong Hui , Fan Taosha , Du Zhijiang , Chirikjian Gregory
Published: January 2016

We present a workspace-density-based (WSDB) method to solve the inverse kinematics of discretely actuated ball-joint manipulators. Intuitively speaking, workspace density measures the flexibility of a robotic manipulator when the end-effector is fixed at a certain pose or position. We use the SE(3) Fourier transform to derive the workspace density for ball-joint manipulators and show that the workspace density has a concise and elegant form. Then we show that the state for each joint is determined by maximizing the workspace density of subsequent sub-manipulators.

We demonstrate our method with several numerical examples. In particular, we show that our method can provide a solution that approximately minimizes the deviation of the end-effector and its computational complexity is linear with respect to the number of joints. Hence our method is very efficient in solving the inverse kinematics of redundant discretely actuated ball-joint manipulators. In addition, we prove that the solution space of our method is reduced from the rotation group SO(3) to a one-dimensional interval.
On the Synthesis of Three-Poses Rigid-Body Guidance Mechanisms
Authors: Figliolini Giorgio , Rea Pierluigi
Published: January 2016

A graphical approach that is based on the use of the pole triangle among the three poles of the finite rotation, along with its circumcircle and those of the three image pole triangles, which intersect each other at the orthocenter of the pole triangle, is presented in this paper.

This method is applied and parameterized in SolidWorks to synthesize different types of mechanisms for any triple of prescribed positions, as four-bar linkages (4R), slider-crank/rocker mechanisms (3RP), double-sliders (2R2P), guiding mechanisms (RPRP).

Finally, the kinematic characteristics of the rigid-body guidance mechanisms for three finitely and infinitesimally separated positions are compared via significant examples.
The Effect of Geometry on the Velocity and Drag Force of Catalytic Micro/Nano-Rockets
Authors: Wang Jiyuan , Li Longqiu , Chang Xiaocong , Li Tianlong , Song Wenping , Zhang Guangyu
Published: January 2016

The hydrodynamic behavior of synthetic self-propelled catalytic micro/nano-rocket moving in low Reynolds number flow is studied theoretically. The inclination angle of the bubble departed from the micro/nano-rocket is related to the radius of the micro/nano-rocket. A unified formula of the drag force for cylindrical, cone-frustum and double truncated cone shapes micro/nano-rocket have been derived. The effect of geometric shapes on the velocity and the drag force is identified by comparing with three circular cross-sectional types of micro/nano-rocket. The average velocity is found to be strongly dependent on semi-cone angle, length, radius of the micro/nano-rocket, the H2O2 concentration and the drag force. This model provides a proficient explanation for propulsion mechanism of a catalytic micro/nano-rocket. This work can be used to optimize catalytic micro/nano-rockets design, which may have potential applications in biomedical and environmental engineering.
Using Molecular Fingerprinting to Infer Functional Similarity in Engineered Systems
Authors: Arlitt Ryan , Manion Charles , Stone Robert , Campbell Matthew , Tumer Irem
Published: January 2016

Design of new and advanced materials with shape-shifting or origami-like capabilities is an area that bears a strong similarity to the design of electromechanical products yet has not leveraged such systematic approaches. In this paper, computational methods to design Metal Organic Responsive Frameworks (MORFs) — which are a theoretical type of material that can change their shape and porosity in response to light — are investigated. However, it is a significant challenge to computationally identify MORFs that are both feasible and useful, i.e., systemic invention (as opposed to discovery) of new MORFs. The proposed framework utilizes the typical product design process to iteratively generate new candidates, evaluate their properties, and then guide the generation of the next set of candidates. A materials designer could then leverage this knowledge to generate structures or substructures with specific functional goals in mind. In this paper an approach to inferring functional similarity of systems using structural information — based on both drug design and database-driven product design — is evaluated. The results demonstrate an observable correlation between structural fingerprints of electromechanical products and electromechanical function. This evidence, combined with the well-established similar property principle in drug design, supports the usage of molecular fingerprinting for providing high-level functional guidance in a MORF design framework based on purely structural information.
Robot-Assisted Ankle Rehabilitation Training on an Adult With Cerebral Palsy: A Case Report
Authors: Meng Wei , Liu Quan , Zhang Mingming , Sheng Bo , Zhou Zude , Ai Qingsong , Xie Shane
Published: January 2016

Robot-assisted rehabilitation techniques have advantages over conventional physiotherapy in terms of control accuracy, repeatability and objectiveness. Several systematic reviews on the effectiveness of robot-assisted ankle rehabilitation have been conducted. It was found that most were effective for the treatment of ankle injuries, although the comparative results could not be identified. However, evidence involving the clinical effectiveness of robotic ankle therapy on adult patients with cerebral palsy (CP) is lacking. This paper presents a case study of robot-assisted ankle rehabilitation on an adult patient with CP. Biomechanical outcomes were evaluated before and after each session with a 10-week-intervention trial by using a Continuous Passive Motion (CPM) device (ARTROMOT®-SP3) for ankle rehabilitation. Both passive and passive-active programs were conducted. Evaluation measures include ankle range of motion (ROM), stiffness and active strength. Experimental results show a distinct recovery progress in ankle movement ability. The participant achieved increased ankle ROM and active strength, and decreased ankle stiffness. This case report demonstrates the effectiveness of robotic training to recover a CP patient’s motor functions and also provides a basis for future study with more clinical trials.
Safety Assessment Process for Human-Robot Handling Tasks
Authors: Malm Timo , Heikkilä Tapio , Ahola Jari M.
Published: January 2016

The needs for using robots to assist human workers in accomplishing heavy tasks in a variety of industries are increasing. Almost by default this implies sharing the work space between robots and human operators. As a consequence, safety issues must be carefully taken into account. We have implemented a pilot system based on a standard industrial robot (KUKA KR120 R2500) for interactive handling of heavy and/or large parts and loads. Here we report the safety analysis and risk assessment of such a system following the harmonized robot standards (ISO 10218-1 & -2), including Preliminary Hazard Analysis (PHA), Use Case Safety Analysis (UCSA) and analysis of system functions and communications.
Iterative Learning and Fractional Reset Control
Authors: HosseinNia S. Hassan , Tejado Inés , Vinagre Blas M. , Chen YangQuan
Published: January 2016

Currently, reset control focuses on using structures with new resetting rules to avoid the occurrence of limit cycles and improve the performance of the system. A common problem in reset control is the steady-state error since it has not the same characteristic as the linear integrator, which causes the occurrence of limit cycles in many cases, specially in first order systems. It is shown that most of the reported methods to prevail this problem — resetting to non-zero values — are not robust. This paper investigates a robust solution for such phenomena using fractional order control and iterative learning control (ILC). The proposed controller is able to eliminate the limit cycle in presence of model mismatch and repetitive disturbances. Likewise, an easy way to tune is described. Simulation results are given to demonstrate its applicability and performance robustness of the designed controller is discussed.
On Synthesis of Contact Aided Compliant Mechanisms Using the Material Mask Overlay Method
Authors: Kumar Prabhat , Sauer Roger A. , Saxena Anupam
Published: January 2016

Contact Aided Compliant Mechanisms (CCMs) are synthesized via the Material Mask Overlay Strategy (MMOS) to trace a desired non-smooth path. MMOS employs hexagonal cells to discretize the design region and engages negative circular masks to designate material states. To synthesize CCMs, the modified MMOS presented herein involves systematic mutation of five mask parameters through a hill climber search to evolve not only the continuum topology (slave surfaces), but also, to introduce the desired rigid, interacting surfaces within some masks. Various geometric singularities are subdued via hexagonal cells though numerous V-notches get retained at the continuum boundaries. To facilitate contact analysis, boundary smoothing is performed by shifting boundary nodes of the evolving continuum systematically. Numerous hexagonal cells get morphed into concave sub-regions as a consequence. Large deformation finite element formulation with Mean Value Coordinates (MVC) based shape functions is used to cater to the generic hexagonal shapes. Contact analysis is accomplished via the Newton-Raphson iterations with load increment in conjunction with the penalty method and active set constraints. An objective function based on Fourier Shape Descriptors is minimized subject to suitable design constraints. An example of a path generating CCM is included to establish the efficacy of the proposed synthesis method.
Complex Analysis of the Dynamic Effects of Car Population Along the Trajectories
Authors: Ferenc Szauter , Tamás Péter , József Bokor
Published: January 2016

The analyses apply new complex model to analyze both road traffic transport processes and spatial nonlinear vehicle dynamic effects. Therefore also the network traffic processes can be analyzed and in a united system the spatial vehicle dynamic processes realized on networks can be attained. Objective the raising the dynamic safety, risk and hazard analysis, reducing the environmental impact of vehicles.
Analysis of the Complex Environmental Impact on Urban Trajectories
Authors: Tamás Péter , Lakatos István , Ferenc Szauter
Published: January 2016

Modeling traffic processes on large-scale road networks leads to the application of positive non-linear systems, Luenberger (1979). Running profiles can be gained from the applied large-size network model based on previous validations, which are sufficiently complex, complicated and built up by accelerations, decelerations and frequent stops. To develop accelerated methods for analyzing complex environmental impact on urban trajectories.

Our planned researches on emission encourage the further standardization and beyond that, the bilateral interoperability. According to our goals we point out on the differences, which have to be taken into account in the urban traffic also, and of which the lab measurements may vary. Real processes operate like this, which differ from those applied in laboratories and on roller brake test bench. In reality, however, vehicle emission strongly depends on driving style; moreover, it is also affected by any change in traffic flow. Significant differences can be realized in various regions and countries. The role of the optimal vehicle control is highlighted in every case. The same can be stated of the environmental loads of pollutant emissions and concerning the vehicle and environment dynamic. The detailed analysis introduced above has big impact on further automotive researches as being rapid and applicable for big number of vehicles providing statistical support.
High-Fidelity Multibody Dynamics Vehicle Model Coupled With a Cohesive Soil Discrete Element Model for Predicting Vehicle Mobility
Authors: Wasfy Tamer M. , Wasfy Hatem M. , Peters Jeanne M.
Published: January 2016

Multibody dynamics and the discrete element method (DEM) are integrated into one solver for predicting the mobility characteristics (including the no-go condition, maximum speed, and required engine torque/power) of ground vehicles on rough off-road soft soil (such as mud and snow) terrains. High fidelity multibody dynamics models are used for the various vehicle systems including: suspension system, wheels, steering system, axle, differential, and engine. A penalty technique is used to impose joint and normal contact constraints. An asperity-based friction model is used to model joint and contact friction. A DEM model of the soil with a cohesive soft soil material model is used. The material model can account for the soil compressibility, plasticity, fracture, friction, viscosity, gain in cohesive strength due to compression, and loss in cohesive strength due to tension. The governing equations of motion are solved along with joint/constraint equations using a time-accurate explicit solution procedure. The model can be used to predict the mobility of ground vehicles as a function of soil type, terrain long slope, and terrain side slope. Typical simulations of a Humvee-type vehicle are provided to demonstrate the model.
A Design Method for the Pinion of a Spiral Bevel Gear Drive Admitting Full Control on the Contact Area and the Transmission Error
Authors: Lei Baozhen , Löwe Harald , Feng Yuqiang , Wang Xunwei
Published: January 2016

Two methods for the design of the pinion apposite to an existing spiral bevel gear are proposed. In both methods, the gear is given by a discrete or smooth parameterization, and the pinion is described in the same way, i.e. it can be produced on a CNC machining center without any further efforts. The first method gives full control on the position, direction, and the extent of the contact area of the pinion. The second method starts by choosing a quite arbitrary transmission function of the gear drive to be designed, and then gives full control on the position, direction, and the width of the contact area. Therefore, both methods provide much freedom in the design process.
Parallel Singularities for the Design of Softening Springs Using Compliant Mechanisms
Authors: Boehler Quentin , Vedrines Marc , Abdelaziz Salih , Poignet Philippe , Renaud Pierre
Published: January 2016

In this paper, the design of nonlinear softening springs using compliant mechanisms is investigated. The use of compliant structures is of great interest, because of the resulting absence of backlash and friction. We demonstrate that the existence of parallel singularities is a necessary condition for the architecture of a compliant softening spring. From this result, two original arrangements of softening springs are derived, with the introduction of traction and torsion softening springs. A synthesis is performed and the traction spring is numerically and experimentally assessed. As nonlinearity can also be obtained from material properties, the interest of using additive manufacturing with multi-material capability is investigated. Rubber-like materials exhibit a hyper-elastic behavior. Their integration in the proposed compliant architecture is shown to be of interest to customize the geometry of a softening spring according to the designer requirements.
Three-Dimensional Plate Theory for Flexible Multibody Dynamics
Authors: Han Shilei , Bauchau Olivier A.
Published: January 2016

In structural analysis, many components are approximated as plates. More often that not, classical plate theories, such as Kirchhoff or Reissner-Mindlin plate theories, form the basis of the analytical developments. The advantage of these approaches is that they leads to simple kinematic descriptions of the problem: the plate’s normal material line is assumed to remain straight and its displacement field is fully defined by three displacement and two rotation components. While such approach is capable of capturing the kinetic energy of the system accurately, it cannot represent the strain energy adequately. For instance, it is well known from three-dimensional elasticity theory that the normal material line will warp under load for laminated composite plates, leading to three-dimensional deformations that generate complex stress states. To overcome this problem, several high-order, refined plate theories have been proposed. While these approaches work well for some cases, they often lead to inefficient formulations because they introduce numerous additional variables. This paper presents a different approach to the problem: based on a finite element semi-discretization of the normal material line, plate equations are derived from three-dimensional elasticity using a rigorous dimensional reduction procedure.
The Contradiction Index (CI): A New Metric Combining System Complexity and Robustness for Early Design Stages
Authors: Göhler Simon Moritz , Howard Thomas J.
Published: January 2016

For complex and integrated products, companies experience difficulties in achieving a satisfactory and consistent functional performance. When a design has “contradicting” parameter/property requirements it often requires fine tuning with numerous design iterations and complex optimizations to find the “sweet spot” where all functional requirements are fulfilled. This often leads to a lack of robustness, where tight tolerances are required and small defects have knock-on effects throughout the product. In this article we propose the Contradiction Index (CI) to gauge how contradicting the requirements of the different parts are with respect to the different functions. This article provides a step-by-step guide for how to estimate the CI for a design. The method is applied to a case study — the FlexTouch®, a Novo Nordisk insulin injection device. When analyzing the CI for each part, against the number of part design iterations, a positive correlation was found. Furthermore, when correlating the CI against the number of challenging tolerances statistical significance was found (p=0.01). It is envisaged that the CI will be a powerful approach to estimate and compare development difficulty and to guide development and design improvements.
Experimental Investigation of the Possibility of a Self-Vacuuming Gearbox for Reducing Windage Loss
Authors: Houjoh Haruo , Iino Takeshi , Matsumura Shigeki
Published: January 2016

Reducing windage loss can be achieved by vacuuming the gear box. This study examines the possibility of implementing a gear pump characteristic with a working helical gear pair inside the gear box itself. An air-tight gear box is constructed and its vacuuming ability, windage loss, and temperature rise in speed range up to 60 m/s are investigated. The vacuuming ability is satisfactory, as it can reduce the pressure to less than 0.02 MPa (absolute), but large heat is generated by adiabatic compression associated with the temperature elevation of about 200°C. This presents excess loss and is due to the pressure difference before and after mesh engagement. Since this loss is proportional to the speed, further higher-speed condition will make total loss smaller than the expected windage loss which is proportional to the third power of the speed. In addition, this self-vacuuming ability can be improved with the assistance of a small vacuum pump to maintain the interior pressure at the beginning of engagement as small as possible. Finally, the feasibility of lubricant feeding is also examined.
Fault Detection of Gears With Different Root Crack Size Using Wavelet
Authors: Hu Xinpeng , Wu Xi , Wang Jixin , Meagher Jim
Published: January 2016

Although tremendous effort has been applied to develop reliable strategies for detecting tooth cracks of gearboxes, these methods have generally fallen short of the required performance. Cracks are usually initiated at the root of a tooth and are very difficult to be identified from time-domain measurement. The vibration signal transformed by wavelet is sensitive to energy change. In this study, the transient vibration variations induced by different sizes of cracks at the tooth root are captured using wavelet. Firstly, as the main parametric excitation, the time-varying gear meshing stiffness caused by the alternating of engaged gear teeth is accurately calculated based on energy method, in which comprehensive deformations including Hertz contact, axial compression, bending, shearing and fillet-foundation deflection are taken into consideration. Moreover, a sophisticated dynamic theoretical model is used to simulate a practical gear system. Unique vibration signatures are captured through the comparison of cracked and perfect gear system.
An Experimental Study on the Motion Transmission Error of Planetary Gear Sets
Authors: Boguski B. , Kahraman A.
Published: January 2016

An experimental study on the overall loaded motion transmission error of planetary gear sets is presented in this study. A test rig is designed and procured for the purpose of measuring the input-to-output transmission error of planetary gear sets within a range of input torque. The test matrix includes three distinct phasing conditions (in phase, sequentially phased and counter-phased) of a four-planet gear set as well as two planet tooth profile modifications. Two different power flow conditions with a fixed planet carrier and a fixed ring gear are considered. The transmission error results indicate that the phasing condition of the gear set is the most critical factor resulting in varying levels and numbers of modulation sidebands around the gear mesh orders. Planetary gear sets having in-phase planet meshes exhibit dominant gear mesh harmonic orders with little sideband activity, while sequentially-phased and counter-phased gear sets show an increase in planetary sideband orders associated with the sun, ring and planet gears. In addition, the power flow condition with fixed carrier is shown to have higher root-mean-square amplitudes of transmission error than configuration with a fixed ring gear.
Influence of Design Parameters on Mechanical Power Losses of Planetary Gear Sets
Authors: Kwon H. S. , Kahraman A.
Published: January 2016

Mechanical (load-dependent) power losses of a planetary gear set occurs primarily along its lubricated rolling-sliding interfaces at the external and internal gear meshes, and planet bearings. The gear mesh originated portion of these losses are influenced by all key gear parameter, tooth profile correction and other parameters dictating the fluid film formation. In this study, a systematic planetary gear design search algorithm is combined with an efficiency formulation to (i) quantify the sensitivity of gear mesh mechanical losses of planetary gear sets to the basic gear design parameters and (ii) investigate the compromise that must take place between the mechanical efficiency and other functional attributes associated with durability and noise performance of the gear set. An example design study is presented at the end to demonstrate both of these points.
Revisiting Plane-Generated Gear Tooth Surfaces: A Novel Design Perspective
Authors: Artoni Alessio , Guiggiani Massimo
Published: January 2016

The teeth of ordinary spur and helical gears are generated by a (virtual) rack provided with planar generating surfaces. The resulting tooth surface shapes are a circle-involute cylinder in the case of spur gears, and a circle-involute helicoid for helical gears. Advantages associated with involute geometry are well known: in particular, the motion transmission function is insensitive to center distance variations, and contact lines (or points, when a corrective surface mismatch is applied) evolve along a fixed plane of action, thereby reducing vibrations and noise emission. As a result, involute gears are easier to manufacture and assemble than non-involute gears, and silent to operate. A peculiarity of their generation process is that the motion of the generating planar surface, seen from the fixed space, is a rectilinear translation (while the gear blank is rotated about a fixed axis): the component of such translation that is orthogonal to the generating plane is the one that ultimately dictates the shape of the generated, envelope surface. Starting from this basic fact, we set out to investigate this type of generation-by-envelope process and to profitably use it to explore new potential design layouts. In particular, with some similarity to the basic principles underlying conical involute (or Beveloid) gears, but within a broader scope, we propose a generalization of these concepts to the case of involute surfaces for motion transmission between skew axes (and intersecting axes as a special case). Analytical derivations demonstrate the theoretical possibility of involute profiles transmitting motion between skew axes through line contact and, perihaps more importantly, they lead to apparently novel geometric designs featuring insensitivity of transmission ratio to all misalignments within relatively large limits. The theoretical developments are confirmed by various numerical examples.