bluuebunny/crossref_metadata_2025 huggingface dataset:
Direct Label Free Detection of Orchid Virus Using a Micro/Nano Hybrid Structured Biosensor
Authors: Wang Wei-Jhen , Lee Chia-Hwa , Li Chin-Wen , Liao Stephen , Jan Fuh-Jyh , Wang Gou-Jen
Published: November 2019

In this study, a label-free detection approach for effective detection of the odontoglossum ringspot virus (ORSV) infected orchids has been developed. We used semiconductor fabrication process to fabricate 1,810 micro/nano hybrid structured sensing electrodes on a 8 inch reclaimed wafer. The self-assembled monolayer (SAM) process was then employed to sequentially modify the electrode surface with 11-mercaptoundecanoic acid (11-MUA), 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide (EDC)/ N-hydroxysuccinimide (NHS), anti-ORSV, and ORSV. EIS was conducted for the ORSV concentration detection. Experimental results demonstrated that the ORSV concentration in a virus infected orchid leaf could be effectively detected. When compared with the ELISA kit, our device possesses a wider linear detection range (0.5–50,000 ng/mL) and a higher sensitivity. The specificity of our device on ORSV detection was also confirmed. Our sensing device retains advantages, such as label-free, lower amounts of the antibody and target sample required, low detection time, and a wider linear detection range. Those results imply the feasibility of our sensing device in field applications.
The Sketch Quality Bias: Evaluating Descriptions of Product Ideas With and Without Visuals
Authors: Kwon Jieun , Kudrowitz Barry
Published: November 2019

Idea visualization is a critical tool in a product development process. From early idea sketches to 3D prototyping, designers often visualize ideas for themselves and others in the process of feedback and refinement. The viewers of these ideas (clients, investors, collaborators, and consumers) rely on these visual presentations to evaluate the potential of a designer’s idea. Although sketching ideas is common practice in the product design industry, little is known about the extent to which presentation quality influences viewers’ evaluations of ideas. This paper examines the power of product sketch quality on perceived idea evaluation. In the present study, a total of 400 participants were asked to evaluate a set of product ideas presented with and without a sketch. The results show that when product sketches were presented, the participants were heavily influenced by the sketch quality when evaluating the value of the idea, and the concept ratings were somewhat different when sketches were not present. The results imply that viewers’ perceptions of idea worthiness are possibly dependent on how an idea is visually presented.
Dynamic Analysis and Parametric Resonance of a Fast Projection System
Authors: Gao Hao , Yang Bingen
Published: November 2019

Fast projection systems are seen in various engineering applications, including weaponry systems. This work is concerned with the vibration of coupled gun barrel-bullet systems. The vibration of the muzzle end of a gun barrel (launching structure) is critical to shooting accuracy and launching safety. Under a rapid and repeated launching process, the launching structure may experience parametric resonance that is induced by accelerating projectiles. In this paper, a mathematical model of the coupled gun barrel-bullet is developed. In the development, the gun barrel is modeled by a cantilever beam; the projectiles are modeled as moving rigid bodies with time-varying velocities; and the dynamic coupling between the gun barrel and projectiles are described by pairs of springs and dampers. With this model, the dynamic response of the coupled system is determined through use of an extended solution domain (ESD) technique, which facilitates systematic solution of the dynamic response of the coupled beam-rigid body system. Numerical results show that parametric resonance can be induced in the launching structure, which is highly dependent on system parameters and projectile launching rate.
On Period-1 and Period-2 Motions of a Jeffcott Rotor System
Authors: Xu Yeyin , Luo Albert C. J.
Published: November 2019

In this paper, the semi-analytical solutions of period-1 and period-2 motions in a nonlinear Jeffcott rotor system are presented through the discrete mapping method. The periodic motions in the nonlinear Jeffcott rotor system are obtained through specific mapping structures with a certain accuracy. A bifurcation tree of period-1 to period-2 motion is achieved, and the corresponding stability and bifurcations of periodic motions are analyzed. For verification of semi-analytical solutions, numerical simulations are carried out by the mid-point scheme.
Design and Simulation Analysis of Vibration Energy Harvesting System Based on ADAMS
Authors: Zhu Ziheng , Xu Lin , Abdelkareem Mohamed A. A. , Zou Junyi , Mi Jia
Published: November 2019

With the recent energy crisis, the new energy harvesting technologies have become one of the hot spots in engineering academic research and industrial applications. By its wide range of application fields, vibration energy harvesting technologies have been gradually developed and utilized in which an efficient and stable harvester technology is one of the recent key problems. In order to improve energy harvesting efficiency and reduce energy loss caused by motor inertial commutation, many mechanical structures or hydraulic structures that convert reciprocating vibration energy into single direction rotation of motor are proposed. Although these methods can improve energy harvesting efficiency, they can have negative effects in some cases, especially in the case of vibration energy harvesting from human beings. This paper proposes a vibration harvesting mechanism with mechanical rectification filter function applied to backpack. The prototype model of the system was established in SolidWorks and imported into ADAMS. Thereafter, dynamic analyses of mechanical rectification filtering characteristics and meshing characteristics of one-way clutch were simulated in ADAMS. Based on ADAMS, parametric design analysis and its influence on the mechanical rectification characteristics were investigated. The simulation results were validated by bench test results. Simulation results is done by ADAMS and the results match well with bench test results.
Precision Evaluation for Cycloidal Gears
Authors: Shih Yi-Pei , Lo Shih-Hung , Sheen Bor-Tyng , Tsai Yi-Hung
Published: November 2019

Cycloidal gear drives have advantages of compact sizes, large reduction ratios, and low backlash. They are particularly suitable for applications in precise positioning and large output torque, such as industrial robots and machine tools. Up to now, the effective precision evaluation of cycloidal gears is lacked in commercial measuring devices. The main goal of this paper is to propose precision evaluation for cycloidal gears. The research focuses on (1) establishing a mathematical model of cycloidal gear and (2) developing a method for precision evaluation of cycloidal gear. The evaluation items cover the following areas of tooth profile and thickness errors, pitch errors, accumulation pitch errors and runout. The profile points measured by a coordinate measuring machine are divided into tooth groups and then formulated as curves using a B-spline curve fitting technique. The precision of cycloidal gear can be further evaluated. A case study on Nabtesco RV-25N is displayed to verified the correctness of the proposed method.
Modeling, Simulation and Assessment of a Hybrid Electric Ferry: Case Study for Mid-Size Ferry
Authors: Feng Yanbiao , Chen Li , Dong Zuomin
Published: November 2019

The hybrid electric propulsion system presents a feasible and attractive fuel cost and emission reduction solution for heavy-duty transportation applications, particularly for large marine vessels. The model of a specially designed hybrid electric powertrain system has been introduced. The work uses the acquired operation and power load patterns of the BC Ferries Skeena Queen as a case study to demonstrate the fuel cost and emission reduction potentials of the electrified technology by comparing results from three powertrain alternatives: traditional diesel engine, diesel-electric, and series hybrid electric. The results showed that the electrification and hybridization could significantly reduce both fuel cost and harmful emissions. The series hybrid electric powertrain system has been targeted in this work due to its relatively small powertrain architecture difference from the traditional diesel-electric powertrain, and the ease of control development.
Addressing Information Gaps in Household Waste Sorting Using a Mobile Application
Authors: Pagels Kelvin Østergaard , Rasmussen Mikkel Bayard , Ramanujan Devarajan
Published: November 2019

The Danish government has outlined a target of recycling 50% of total household waste by the year 2022. Improving household waste sorting is an important consideration towards achieving this goal. This paper focuses on understanding existing waste sorting practices among Danish residents and exploring whether a mobile application can help address any existing information gaps. We conducted a preliminary survey (N = 180) that assessed preference for sorting strategies and the types of waste sorted. Following this a more detailed survey was conducted (N = 357) that assessed residents’ motivation to sort household waste, knowledge of local sorting requirements, information gaps that prevent effective sorting, and need for specific features in a mobile application. Results show over one-third of respondents felt they needed additional waste sorting information. Respondents had fewer inaccuracies disposing items within a single waste stream (e.g., electronics waste) compared to items with mixed waste streams (e.g., milk carton with a plastic cap). Based on these findings we propose the design of a mobile application that can potentially improve household waste sorting.
Topology Optimization of Compliant Mechanisms Based on Interpolation Meshless Method and Geometric Nonlinearity
Authors: Zhang Yonghong , Zhao Zhenfei , Zhang Yaqing , Ge Wenjie
Published: November 2019

In order to prevent mesh distortion problem arising in topology optimization of compliant mechanism with massive displacement, a meshless Galerkin method was proposed and studied in this paper. The element-free Galerkin method (EFG) is more accurate than the finite element method, and it does not need grids. However, it is difficult to impose complex boundaries. This paper presents a topology optimization method based on interpolation meshless method, which retains the advantages of the finite element method (FEM) that is easy to impose boundary conditions and high accuracy of the meshless method. At the same time, a method of gradually reducing step is proposed to solve the problem of non-linear convergence caused by low-density points in topology optimization. Numerical example shows that these techniques are valid in topology optimization of compliant mechanism considering the geometric nonlinearity, and simultaneously these techniques can also improve the convergence of nonlinearity.
Feasibility Study of a Capacitive MEMS Filter Using Electrostatic Levitation
Authors: Pallay Mark , Towfighian Shahrzad
Published: November 2019

We introduce a capacitive MEMS filter that uses electrostatic levitation for actuation and sensing. The advantage of this electrode configuration is that it does not suffer from the pull-in instability and therefore tremendously high voltages can be applied to this system. A large sensing voltage will produce a large output signal, which boosts the signal to noise ratio. The filter outputs about a 110mV peak-to-peak signal when operated at 175V, and can be boosted to 175mV by increasing the voltage to 250V. Because pull-in is eliminated, voltages much higher than 250V can be applied. An outline of the filter design and operating principle is discussed. A model of the filter is derived and analyzed to show the mechanical response and approximate peak-to-peak signal output. This study shows the feasibility of a capacitive sensor that is based on electrostatic levitation, and outlines the advantages it has over traditional parallel-plate electrode configurations. This design is promising for signal signal processing applications where large strokes are important.
Eliminating Peak Impact Forces by Customizing the Passive Foot Dynamics of Legged Robots
Authors: Rond Jesse J. , Cardani Michael C. , Campbell Matthew I. , Hurst Jonathan W.
Published: November 2019

Impact forces are a destructive, yet common occurrence in legged locomotion. Every step produces a collision when the leg’s inertia immediately stops upon ground contact. This results in peak impact forces and high frequency vibrations that resonate through the system, damage components, and complicate control algorithms. Rubber or other damping material is the assumed solution for mitigating these impacts. However, we show the benefit of using foot springs where both stiffness and maximum compression are customized to the leg. Such springs eliminate peak impact forces by gradually bringing the leg’s inertia to rest. The maximum compression point (i.e. a hard stop) then provides a rigid surface during stance. We provide a methodology for designing this passive dynamic foot that is validated through simulation and physical testing. Our results show this methodology reduces rigid body impacts and foot vibrations in a way traditional methods, reliant upon rubber or damping, are yet to achieve.
The Trajectory of Psychological Safety in Engineering Teams: A Longitudinal Exploration in Engineering Design Education
Authors: Miller Scarlett , Marhefka Jacqueline , Heininger Katie , Jablokow Kathryn , Mohammed Susan , Ritter Sarah
Published: November 2019

Although teamwork is being integrated throughout engineering education because of the perceived benefits of teams, the construct of psychological safety has been largely ignored in engineering research. This omission is unfortunate, because psychological safety reflects collective perceptions about how comfortable team members feel in sharing their perspectives and it has been found to positively impact team performance in samples outside of engineering [20]. Engineering team research has also been crippled by “snap-shot” methodologies and the resulting lack of investigation into the dynamic changes that happen within a team over course projects. This is problematic, because we do not know when, how, or what type of interventions are needed to effectively improve “t-shaped” engineering skills like teamwork, communication, and engaging successfully in a diverse team. In light of these issues, the goal of the current study was to understand how psychological safety might be measured practically and reliably in engineering student teams over time. In addition, we sought to identify the trajectory of psychological safety for engineering design student teams and identify the potential factors that impact the building and waning of psychological safety in these teams. This was accomplished through a 4-week study with 12 engineering design teams where data was captured at six time points. The results of this study present some of the first evidence on the reliability of psychological safety in engineering student populations. The results also help begin to answer some difficult fundamental questions on supporting team performance in engineering education.
A General Purpose Formulation for Nonsmooth Dynamics Including Large Rotations: Application to the Woodpecker Toy
Authors: Galvez Javier , Cosimo Alejandro , Cavalieri Federico J. , Cardona Alberto , Brüls Olivier
Published: November 2019

The aim of this work is to extend the finite element multibody dynamics approach to problems involving frictional contacts and impacts. Since rigid bodies and joints involve bilateral constraints, it is important to avoid any drift phenomenon. Therefore, the nonsmooth generalized-α method is used, which imposes the constraints both at position and at velocity levels. Its low intrusiveness allows one to reuse an existing library of elements without major modifications. The study of the woodpecker toy dynamics sets up a good example to show the capabilities of the nonsmooth generalized-α within the context of a general finite element framework. This example has already been studied by many authors who generally adopt a model with a minimal set of coordinates and small rotations. We show that using a finite element approach, the equations of motion can be assembled automatically, and large rotations can be easily considered.
Creating Robust Passive Multi-Loop Wearable Hand Devices
Authors: Robson Nina , Chen Bin Yun , Won Jong-Seob , Soh Gim Song
Published: November 2019

This paper describes a process for assessing multi-loop wearable devices that use a common slider to passively drive the exo-fingers for the physical training of people with limited hand mobility. Each finger design, except for the thumb, is based on an RRR serial chain, termed backbone, constrained into a multi-loop eight-bar slider mechanism using two RR constraints. The thumb utilizes a planar RR backbone chain constrained into a parallel four bar slider. During the physical task acquisition experiments, the subject’s tip finger trajectories are captured using an optical motion capture and its dimensions are set such that they match each of the fingers kinematics as closely as possible. The dimensional synthesis procedure can yield a variety of design candidates that fulfill the desired fingertip precision grasping trajectory. Once it is ensured that the synthesized fingertip motion is close to the physiological fingertip grasping trajectories, performance assessment criteria related to user-device interference and natural joint angle movement are taken into account. After the most preferred design for each finger is chosen, minor modifications related to substituting the backbone chain with the wearer’s limb to provide the skeletal structure of the customized passive device are made. To illustrate the proposed technique, the development of a 3D prototype model of a passively actuated Closed Loop Articulated Wearable (CLAW) hand is presented. The CLAW hand performance with respect to wear-ability and robustness was assessed. Preliminary test results with healthy subjects show that the CLAW hand is easy to operate and able to guide the user’s fingers without causing any discomfort, ensuring both, precision and power grasping in a natural manner. The lack of electrical actuators and sensors simplifies the control, resulting in a lightweight and cost-effective solution for grasping of a variety of objects with different sizes. This work establishes the importance of incorporating novel design candidate assessment techniques, based on human finger kinematic models, within the conceptual design level that can assist in finding robust design candidates with naturalistic joint motion.
Analyzing Customer Needs of Product Ecosystems Using Online Product Reviews
Authors: Ayoub Jackie , Zhou Feng , Xu Qianli , Yang Jessie
Published: November 2019

It is necessary to analyze customer needs of a product ecosystem in order to increase customer satisfaction and user experience, which will, in turn, enhance its business strategy and profits. However, it is often time-consuming and challenging to identify and analyze customer needs of product ecosystems using traditional methods due to numerous products and services as well as their interdependence within the product ecosystem. In this paper, we analyzed customer needs of a product ecosystem by capitalizing on online product reviews of multiple products and services of the Amazon product ecosystem with machine learning techniques. First, we filtered the noise involved in the reviews using a fastText method to categorize the reviews into informative and uninformative regarding customer needs. Second, we extracted various customer needs related topics using a latent Dirichlet allocation technique. Third, we conducted sentiment analysis using a valence aware dictionary and sentiment reasoner method, which not only predicted the sentiment of the reviews, but also its intensity. Based on the first three steps, we classified customer needs using an analytical Kano model dynamically. The case study of Amazon product ecosystem showed the potential of the proposed method.
In-Plane Compressive Strength Analysis of Novel Folded Honeycomb Material
Authors: Ma Ruijun , Cai Jianguo , Wang Yutao , Feng Jian
Published: November 2019

Two novel folded honeycombs with miura pattern are proposed in this paper. Geometry parameters for design process are given and explained. The in-plane compressive strength of the two proposed novel folded honeycombs has been studied by means of finite element simulation using ABAQUS. Quasi-static loading in two in-plane direction is selected to obtain the deformation and plateau stress. The unique collapse modes and plateau state are obtained and discussed. Compared with the conventional honeycombs, the in-plane strength of the two folded honeycombs is improved significantly. The negative Poisson’s ratio effect and buckling-restrained mechanism are introduced to illustrate the improvement. It is summarized that plateau stress under in-plane loading is improved with the included angle of miura pattern decrease for the local buckling is restrained. The folded auxetic honeycomb has the best in-plane strength for its presented negative Poisson’s ratio in two loading cases.
Preliminary Study on the Manufacturing Feasibility of Microfeatures for Microfluidics by DLP Stereolithography
Authors: Rebaioli Lara , Fassi Irene
Published: November 2019

Lab on Chips (LOCs) are devices mostly based on microfluidics (i.e. structures for liquid handling with cross sections of 1–500 μm and femtoliter to nanoliter volume capacity), which allow to perform one or several chemical, biochemical or biological analysis in a miniaturized format on a single chip. The emerging Additive Manufacturing (AM) processes could produce a complete LOC with microscale complex 3D shapes in a single step without the need for assembly processes. Stereolithography, especially when exploiting the Digital Light Processing (DLP) technology, is the most promising AM process for this purpose. In this study, a suitable benchmark part was designed to assess the feasibility of manufacturing microfeatures by DLP-SLA and to evaluate the performance of the employed system in terms of the minimum feature size, dimensional accuracy and spatial repeatability. A proper experimental campaign was specifically studied to point out the effect of the main process parameters (namely, layer thickness and exposure time) and the feature position within the building platform on the process performance. The results demonstrated the manufacturing feasibility of the selected microfeatures. Moreover, they showed that both the process parameters influence the minimum feasibile feature size and that the dimensional accuracy changes with the feature position.
Periodic Motions in a Discontinuous Dynamical System With Two Circular Boundaries
Authors: Guo Siyu , Luo Albert C. J.
Published: November 2019

In this paper, periodic motions in a discontinuous dynamical systems are studied. The discontinuous dynamical system has three domains partitioned through two circular boundaries. On the three domains, there are three distinct dynamical systems. From the G-functions, the switchability conditions of a flow from one domain to anther domain at the boundary are developed. The flow mappings from a boundary to a bounbary are developed for each domain and boundary. From the mapping structures, periodic motions in the discontinuous dynamical system are predicted. Numerical simulations of periodic motions and motion switchability at boundaries are presented in the discontinuous dynamical system.
Pseudo-Rigid Body Dynamic Modeling of Compliant Members for Design
Authors: Vedant  , Allison James T.
Published: November 2019

Movement in compliant mechanisms is achieved, at least in part, via deformable flexible members, rather than using articulating joints. These flexible members are traditionally modeled using Finite Element Models (FEMs). In this article, an alternative strategy for modeling compliant cantilever beams is developed with the objectives of reducing computational expense, and providing accuracy with respect to design optimization solutions. The method involves approximating the response of a flexible beam with an n-link/m-joint Pseudo-Rigid Body Dynamic Model (PRBDM). Traditionally, PRBDM models have shown an approximation of compliant elements using 2 or 3 revolute joints (2R/3R-PRBDM). In this study, a more general nR-PRBDM model is developed. The first n resonant frequencies of the PRBDM are matched to exact or FEM solutions to approximate the response of the compliant system. These models can be used for co-design studies of flexible structural members, and are capable of modeling higher deflection of compliant elements.
Enhancing the Performance of an FSAE Car
Authors: Schiavinotto Giovanni , Meneghetti Giovanni , Veneri Matteo , Massaro Matteo
Published: November 2019

The paper addresses the modelling, validation, and analysis of an FSAE car. The aim is to devise a method for enhancing its dynamic performance. The validation of the model is carried out in acceleration, skidpad and slalom tests, against the experimental data recorded within the 2018 FSAE competition in Varano de’ Melegari (Italy). It is shown that the skidpad and slalom performance can be significantly enhanced by varying the trim of the car, namely toe, camber, steering geometry and anti-roll bars. Implications on steering characteristics are also discussed, for investigating the effects on handling.
Towards a Broad Use of Gamification Based on Hand Tracking in Post Stroke Patients
Authors: Regazzoni Daniele , Vitali Andrea , Rizzi Caterina
Published: November 2019

In the last years, the advent of innovative technologies for tracking human motions is increasing the interest of physicians and physiotherapist, who would like to introduce new instruments for a more objective assessment of the rehabilitation processes. At present, many motion tracking systems have been developed and their ease of use and low-cost may represent the key aspects for which these systems could be really adopted both in rehabilitation centers and in rehabilitation programs at home. Several research studies confirmed the importance of continuing rehabilitation programs at home with the aim to maintain patients’ health condition at a suitable level for daily life activities. Physicians and physiotherapists need methods and tools, which can be simply adaptable for each type of patients’ category and type of rehabilitation according to the assessed pathology. For achieving this need, the technology has to be suitable for both the patient side and medical personnel side. The most suitable technology for the patients are motion tracking devices which can be used through traditional IT, such as laptops, smartphones and tablets. Also for medical personnel the ease of use is very important, physicians would like to check the patient’s rehab exercises according to their medical knowledge by exploiting daily life technology. This research work investigates on which are the best user-friendly programming tools and low-cost technology for 3D hand and finger tracking for the development of a serious game for rehabilitation exercises. The tasks are designed according to physiotherapists’ recommendations, in order to be customizable for any single user. The following sections will describe the method, the tools adopted, and the application developed.
Integrating Dry Adhesives and Compliant Suspension for Track-Type Climbing Robots
Authors: Powelson Matthew W. , Demirjian Wesley A. , Canfield Stephen L.
Published: November 2019

Climbing robots using dry adhesives in the literature typically exhibit minimal payload and are considered useful for tasks involving light-weight sensors, such as surveillance or exploration. Existing designs demonstrate small payloads primarily because they either employ minimal adhesion area or fail to distribute the adhesion forces over the adhering region of these robots. Further, existing design methods do not demonstrate scalability of payload-to-vehicle size and, in fact, indicate that such robots are not scalable. However, dry adhesives routinely demonstrate adhering pressures in the range of 20–50 kPa which suggests that a 30 × 30 cm robot could have a payload on the order of 20–50 kg.

This paper presents a step-by-step approach for designing track-type dry adhesive climbing robots to achieve high payloads. The aforementioned design steps are then experimentally validated, showing that high payloads should theoretically be possible when using dry adhesives to climb. By integrating a general adhesion model with a suspension system, this design procedure can be used to design climbing robots that distribute the payload over a large adhesive area. The models behind the design procedure (developed previously [1] but summarized here) simultaneously consider the behavior of both the adhesive material at the track-surface interface and the distribution of the adhesive forces over the full contact surface. When each of these criteria are satisfied, track-type climbing robots can be designed to carry high payloads, thus enabling applications previously thought to be impossible.
Development of Three-Dimensional MEMS Biochemical Sensors for Low Concentration Aqueous Solutions
Authors: Mazrouei Roya , Kier Bryan , Shavezipur Mohammad
Published: November 2019

Three-dimensional biochemical sensors are developed that can be used for chemical and biological detection in aqueous solutions and suspensions. The sensors are fabricated using a standard polycrystalline silicon process, PolyMUMPs, and can detect chemicals and biomarkers in low concentrations in near real time. The sensors made of a stack of electrodes allowing the solution to occupy the space between the layers of electrodes and have a larger interface with the electrodes. The sensors use electrochemistry impedance spectroscopy (EIS) for detection and therefore increasing the solution-electrode interface improves the sensitivity of the sensor. To demonstrate the applicability of the proposed sensor design, experimental measurements are used to characterize and compare the 3D sensors with conventional 2D interdigitated sensors. Diethylhexyl phthalate (DEHP) solution is used as the target chemical, and the 2D and 3D biochemical sensors are exposed to different concentrations of DEHP solution. An LCR meter is used to sweep the frequency and determine the impedance of the sensor-solution combination. The test results show that the three-dimensional sensors have higher sensitivity than 2D interdigitated ones verifying the advantage of the new sensor design over existing conventional sensors. The proposed sensors can also be used for detection of biological markers such as cells, proteins and enzymes in aqueous solutions.
Comparison of Surface Tension Models in Smoothed Particles Hydrodynamics Method
Authors: Yang Lijing , Rakhsha Milad , Negrut Dan
Published: November 2019

We compare two surface tension models to solve two-phase fluid interaction problems in the context of the mesh-free Smoothed Particles Hydrodynamics (SPH) method. The Continuum Surface Force (CSF) model (later extended to Continuum Surface Stress, CSS), originally derived from grid-based numerical methods, requires an accurate estimation of the interface curvature to express the surface tension. Unlike CSF, the Inter-Particle Force (IPF) model is more robust in this regard as it draws on a molecular dynamics foundation by considering how the pairwise interaction forces between particles within a cutoff distance act in relation to producing the surface tension. Herein, we rely on second-order consistent gradient and Laplacian operators to improve the accuracy of SPH formulations as well as on a particle shifting technique to “disorder” particles from non-differentiable interface geometries. A 3D liquid droplet deformation test is used to compare CSF and IPF in terms of their pressure field and kinetic energy dissipation accuracy.
A Cable-Driven Parallel Robot With an Embedded Tilt-Roll Wrist
Authors: Lessanibahri Saman , Cardou Philippe , Caro Stéphane
Published: November 2019

This paper addresses the optimum design, configuration and workspace analysis of a Cable-Driven Parallel Robot with an embedded tilt-roll wrist. The manipulator is a hybrid robot consisting in an under-constrained moving-platform accommodating a tilt-roll wrist. The embedded wrist provides large amplitudes of tilt and roll rotations and a large translational workspace obtained by the moving-platform. This manipulator is suitable for tasks requiring large rotation and translation workspaces like tomography scanning, camera-orienting devices and visual surveillance. The moving-platform is an eight-degree-of-freedom articulated mechanism with large translational and rotational workspaces and it is suspended from a fixed frame by six cables. The manipulator employs two bi-actuated cables, i.e., cable loops to transmit the power from motors fixed on the ground to the tilt-roll wrist. Therefore, the manipulator achieves better dynamic performances due to a lower inertia of its moving-platform.
A Sensitive Resonant Gas Sensor Based on Multimode Excitation of a Buckled Beam
Authors: Hajjaj Amal Z. , Jaber Nizar , Alcheikh Nouha , Younis Mohammad I.
Published: November 2019

The quest for ultra-sensitive low-cost miniaturized gas sensors in the past few decades has sparked interest to seek alternative approaches other than the conventional gas sensors that need large surface areas and special chemicals for functionalization. MEMS thermal conductivity based gas sensors [1, 2] have been shown to be among the promising candidates since they do not rely on gas absorption or chemical reactions. These sensors show long lifetime and great stability compared to conventional gas sensor. The thermal conductivity based gas sensors rely on the resistance variation of the heated structures due to gas exposure [1]. Typical values of resistance changes are less than few percent. Here, we present a thermal conductivity based gas sensor relying on frequency shifts of an electrothermally heated bridge operated near the buckling point, which leads to ultra-high sensitivity.
Teleoperated Vehicle-Perspective Predictive Display Accounting for Network Time Delays
Authors: Prakash Jai , Vignati Michele , Arrigoni Stefano , Bersani Mattia , Mentasti Simone
Published: November 2019

Variable network time-delays in data-transmission is the major problem in tele-operating a vehicle. Even on LTE network, variability of these delays is high (70–150 ms ping).

This paper presents an innovative approach of providing the remote operator a forecasted video stream which replicates future perspective of vehicle’s FOV upon reception of maneuvering commands. First, vehicle position is predicted accounting for its speed and data transmission delays. Then perspective image transformation2 is performed to get exact new perspective of vehicle FOV corresponds to the predicted position. This approach addresses both issues, time-delays as well as its variability. Only one display, which shows frontward FOV is availed for mock-up.
Effect of Rubber Material Properties on Steady-State Flat Belt Response
Authors: Wasfy Tamer M. , Wasfy Hatem M.
Published: November 2019

Belt-drives are used to transmit power between rotational machine elements in many mechanical systems such as industrial machines, home appliances, and internal combustion engines. The belt cross-section typically consists of axially stiff tension cords (made of steel or polyester strands) embedded in a rubber matrix. The rubber matrix provides the friction interface between the belt and the pulleys through which mechanical torque is transmitted. In this paper, the effect of the rubber’s Young’s modulus and Poisson’s ratio on the steady-state belt normal, tangential and axial stresses, average belt slip, and belt-drive energy efficiency is studied using a high-fidelity flexible multibody dynamics model of a flat belt-drive. The belt’s rubber matrix is modeled using three-dimensional brick elements and the belt’s cords are modeled using one dimensional truss elements. Friction between the belt and the pulleys is modeled using an asperity-based Coulomb friction model. The pulleys are modeled as rigid bodies with a cylindrical contact surface. The equations of motion are integrated using a time-accurate explicit solution procedure.
An Automated Approach to Recording and Analyzing Design Activities Using a Graphical User Interface
Authors: Adly Taha Fares M. , Adly Taha Ramez M. , West Keegan , Fazelpour Mohammad , Herrmann Jeffrey W. , Polvinale Matthew Anthony
Published: November 2019

Design researchers use protocol studies to understand the cognition of designers and how they think. Although different qualitative and quantitative methods have been employed, analyzing protocol data often requires manual coding, which is tedious, time-consuming, and susceptible to human error. To address these challenges, this paper presents an automated method to record and analyze the designer’s actions. To demonstrate the proposed method, we designed and conducted an experimental study that used a graphical user interface to record design actions while the designer solves a factory layout problem. Then, we used spectral clustering to analyze the data and identify the subproblems that the designer considered. The final design layouts were evaluated using two metrics: travel distance and adjacency score. Our automated method to record and analyze designers’ actions provides a framework to analyze protocol study data sets objectively and quickly.
Graduate Students’ Mental Models: An Investigation Into the Role of Function in Systems Understanding
Authors: Murphy Alexander R. , Banks Henry D. , Nagel Robert L. , Linsey Julie S.
Published: November 2019

Elicited student mental models reveal students’ understanding of a given system as well as their ability to communicate knowledge of that system to others. Understanding how students form and developmental models of systems is critical to the progress of engineering education. In this work, graduate students’ mental models of common household products are measured before and after instruction on functional modeling and functional decomposition. These mental models are measured using previously published, but still developing mental model instruments. The included systems are a hair dryer, clothes dryer, and vacuum cleaner with accompanying scoring rubrics. Results show statistically significant improvements on average mental model rubric scores on all three given systems after the functional modeling intervention. These results suggest that curriculum content on functional modeling and decomposition likely improves students’ mental models of engineering systems and their ability to communicate their knowledge about those systems. As we improve our understanding of how students form, change, and communicate their mental models of engineering systems, educators can shape curriculum to facilitate the skills necessary for comprehensive systems understanding.
Framing Product Circularity Performance for Optimized Green Profit
Authors: Saidani Michael , Kim Harrison , Yannou Bernard , Leroy Yann , Cluzel François
Published: November 2019

The purpose of this paper is to develop and discuss a framework aiming at monitoring and optimizing the circularity performance of products for ensuring and facilitating green profit design trade-offs whilst meeting or anticipating end-of-life regulations during the design and development process of industrial products. The proposed framework is used to extend the Green Profit Model — an optimization model to maximize the total profit from the sales of new and remanufactured products, while achieving environmental impact savings — by adding a third dimension to this model, which is the circularity performance. As such, in addition to remanufacturing, it covers a wider spectrum of circular economy practices, leading to additional economic opportunities and environmental trade-offs between maintenance, reuse, remanufacturing and recycling at a product, parts and material levels. A first formulation of this extended optimization model is given and discussed through an illustrative example. By connecting the circularity performance of products with possible economic profit and environmental impact savings, it thus contributes in advancing the understanding and linkages in the area of circular design, life cycle analysis, industrial decision-support tool, and environmental regulations. Concretely, practical implications for both design engineering and green policy making are highlighted.
Structural Consequence Analysis: Towards the Quantification of Component Consequential Importance in System Architecture Design
Authors: Walsh Hannah S. , Hejase Mohammad , Hulse Daniel , Brat Guillaume , Tumer Irem Y.
Published: November 2019

There is a major push in safety-critical systems to consider system risk early in the design process in order to avoid costly redesign later on. However, existing techniques, which may be labor-intensive and be subject to many sources of uncertainty, rely on failure mode and failure rate data, which can only be estimated in the early design phase. This paper proposes a network-based technique for assessing the consequential importance of a particular component to enable designers to consider hazards in the design of the system architecture without the use of estimated failure rates. Structural consequence analysis represents connectivity between components with a network and provides an explicit representation of risk prevention and mitigation techniques, such as redundancy. The network is augmented with a measure of the consequence of the failure of the “end” components, or sinks, which can be backpropagated through the network to compute the consequence associated with the failure of all components. Based on this consequence, designers can consider mitigation strategies, such as redundancy or increased component reliability. The approach is demonstrated in the design of an electric system to control an aileron of an unmanned aircraft system (UAS). It is found that structural consequence analysis can identify potentially important components without failure rate data, allowing designers to proactively design for risk earlier in the design process.
Asymmetric Energy Harvesting and Hydraulically Interconnected Suspension: Modeling and Validations
Authors: Chen Yuzhe , Qin Bonan , Guo Sijing , Yu Liangyao , Zuo Lei
Published: November 2019

This paper introduces a new form of energy-harvesting suspension that is integrated in a hydraulically interconnected suspension (HIS) system. The combined energy-harvesting and hydraulic interconnection features provide improved energy efficiency and vehicle dynamics performance. A half car model and a full car model are developed to validate the effectiveness of this design. Different dynamic input scenarios are used for model simulation, which includes single-wheel sinusoidal input, two-wheel sinusoidal input and double lane change test. The system performs better than a conventional suspension system in rolling dynamics in the cases of the single-wheel road input and double lane change test. The heaving dynamics is dependent on the frequency of the road input. The energy harvesting can generate up to 421 w at 4 Hz and 40 mm (peak to peak) road input.
Examining the Effect of Friction During Dry Sliding on Select Thermoplastics
Authors: Madison Adam , Koren Kyle , Kames Elisabeth , Morkos Beshoy
Published: November 2019

This paper outlines a preliminary case study which examines the effect of friction on select thermoplastics during high load, low velocity, and dry sliding wear applications. The primary factors investigated were temperature increase, mass loss, and surface condition of the material. The goal of this research is to identify the best material choice for this application. Eight different thermoplastics were observed in this study. The thermoplastics include variations of polyethylene (PE), polyamide (Nylon), and polytetrafluoroethylene (PTFE). An overarching goal of this study is to develop a standard wear property table for the select thermoplastics, as they are not readily available like material property tables for other materials.

The results obtained show that the temperature of the materials generally increased over time, with some materials experiencing greater temperature increase than others. The PTFE materials exhibited the most substantial material loss while the PE materials had the highest increase in temperature during the testing period. Most Nylon composites generated noise during testing, with the exception of one variant: Bearing Grade Nylon. After all factors were considered, Bearing Grade Nylon was chosen for the aforementioned application due to its negligible mass loss, minor surface damage, and temperature increase relative to other thermoplastics tested throughout all trials.
Benefits of a Short-Term Engineering Study Abroad: A Survey of Students Over the Past 15 Years
Authors: Hunter Jacob G. , Mattson Christopher A. , Magleby Spencer P.
Published: November 2019

Since 2004, Brigham Young University has offered a graduate study abroad course in mechanical engineering to help prepare students to be leaders in globally-influenced product development organizations. The course is offered as a study abroad program where faculty lead a group of students across several countries to learn about global product development. This is accomplished in a 2–3 week time period consisting of visits to companies and universities as well as participation in cultural activities. While much research has been done on the benefits of study abroad, it remains unclear how effective study abroad programs are at helping engineering students, especially short-term study abroad programs. The purpose of this paper is to present and examine the benefits of a short-term, study abroad program to engineering students. Data was collected from students who have taken the Global Product Development Course over the past 15 years in a mixed methods survey. Trends show that technical and cultural visits positively effect engineering students in their perception of global product development. It is also shown that a short, 2–3 week, engineering study abroad program can be as or more effective than traditional study abroad programs in certain areas.