bluuebunny/crossref_metadata_2025 huggingface dataset:
“Thus, I Had to Go With What I Had”: A Multiple Methods Exploration of Novice Designers’ Articulation of Prototyping Decisions
Authors: Menold Jessica , Berdanier Catherine , McComb Christopher , Hocker Emma , Gardner Lisa
Published: November 2018

Effectively communicating designs to stakeholders or end users is a critical step in the design process yet can be a difficult challenge for engineers. Prototypes are unique tools that can enhance communication between these two groups, as prototypes are physical manifestations of the designer’s mental model. Previous work has demonstrated that novice designers often struggle to use prototypes as communication tools. We argue that it is critical that engineering students learn to fully leverage prototypes, and thus the current work sought to understand the relationship between argumentation, prototyping, and design decisions. In order to understand the communication patterns of novice designers during a prototyping task, a controlled study was conducted with a total of 46 undergraduate engineering students. The analysis of quantitative and qualitative data point to the intricate linkages between how students make material decisions and how they justify those decisions.
Design and Optimization of Multiple Single-DOF Tuned Mass Dampers Based on Flexure Design Theory
Authors: Ma Wenshuo , Yang Yiqing , Yu Jingjun
Published: November 2018

Vibration is an undesirable phenomenon in engineering, and its avoidance has received considerable attention, especially for the cases of precision engineering. Since the dynamic performance of precision mechanisms are most likely to be restricted by their 1st modes, multiple single degree of freedom (SDOF) tuned mass dampers (TMDs) are designed to suppress a translational moving platform with single mode. The TMDs are designed with optimal stiffness and damping ratios, which are acquired by numerical optimization using minimax algorithm. Each SDOF TMD is implemented via the graphical approach and modeled by substructure dynamic modeling techniques. Results of finite element analysis (FEA) show that the maximum amplitude of frequency response function (FRF) of the primary system can be damped to 89.14% when N is 3, which validates the vibration mitigation by employing the designed TMDs. Furthermore, the proposed design routine provides a guidance for implementation of multiple SDOF TMDs.
Integrating Intelligence and Knowledge of Human Factors to Facilitate Collaboration in Manufacturing
Authors: Oliff Harley , Liu Ying , Kumar Maneesh , Williams Michael
Published: November 2018

The implementation of automation has become a common occurrence in recent years, and automated robotic systems are actively used in many manufacturing processes. However, fully automated manufacturing systems are far less common, and human operators remain prevalent. The resulting scenario is one where human and robotic operators work in close proximity, and directly affect the behavior of one another. Conversely to their robotic counterparts, human beings do not share the same level of repeatability or accuracy, and as such can be a source of uncertainty in such processes.

Concurrently, the emergence of intelligent manufacturing has presented opportunities for adaptability within robotic control. This work examines relevant human factors and develops a learning model to examine how to utilize this knowledge and provide appropriate adaptability to robotic elements, with the intention of improving collaborative interaction with human colleagues, and optimized performance. The work is supported by an example case-study, which explores the application of such a control system, and its performance in a real-world production scenario.
Kinematic and Potential Energy Analysis of Self-Adaptive Robotic Legs
Authors: Fedorov Dmitri , Birglen Lionel
Published: November 2018

This paper presents how the kinematic and potential energy analysis of self-adaptive robotic legs can help to improve their performances with respect to their ability to overcome obstacles and the required actuation torque to do so. Self-adaptive leg mechanisms, inspired by the underactuated linkages used in grasping, generally rely on a single degree of freedom (DOF) to generate a trajectory at its endpoint that is appropriate for walking applications. When colliding with an unexpected obstacle, a second DOF in the leg automatically engages and creates a motion allowing the leg to overcome said obstacle. Since this behavior is obtained mechanically, with no sensor or control, these robotic legs are referred to as self-adaptive. In this paper, the conditions for the passive adaptation to obstacles are first briefly recalled. Then, the range of obstacles for which this adaptation is possible is determined through the analysis, using potential energy, of the mechanism workspace and it is shown how the results are connected to its kinematics. In particular, the influence of the shape of the terminal link of the leg is discussed with two compared examples. Finally, practical designs and especially the relative advantages of various locking mechanisms, required to improve stability during the support phase of the leg trajectory, are discussed.
Design of a Test Platform for the Determination of Lithium-Ion Batteries State-of-Health
Authors: Capitaine Jules-Adrien , Wang Qing
Published: November 2018

This paper presents a novel design for a test platform to determine the State of Health (SOH) of lithium-ion batteries. The SOH is a key parameter of a battery energy storage system and its estimation remains a challenging issue. The batteries that have been tested are 18650 li-ion cells as they are the most commonly used batteries on the market. The test platform design is detailed from the building of the charging and discharging circuitry to the software. Data acquired from the testing circuitry is stored and displayed in LabView to obtain charging and discharging curves. The resulting graphs are compared to the outcome predicted by the battery datasheets, to verify the platform delivers coherent values. The SOH of the battery is then calculated using a Coulomb Counting method in LabView. The batteries will be discharged through various types of resistive circuits, and the differences in the resulting curves will be discussed. A single battery cell will also be tested over 30 cycles and the decrease in the SOH will be clearly pointed out.
Characteristics of Hydrogen Combustion in a Rapidly Mixed Tubular Flame Burner
Authors: Shi Baolu , Li Bo , Zhao Xiaoyao , Chu Qingzhao , Wang Ningfei
Published: November 2018

Hydrogen is a carbon-free fuel expecting to be used in either combustion devices or fuel cells. However, high diffusivity and reactivity of hydrogen may result in potential hazards of flame flash back in conventional combustion systems, which greatly restricts the wide application of hydrogen fuel in engines. In this study, an inherently safe technique of rapidly mixed tubular combustion is adopted to attempt the hydrogen combustion, in which fuel and oxidizer are individually injected into the cylindrical combustor. Two methods of fuel and oxidizer feeding are tested: (1) hydrogen and air are separately injected from fuel and oxidizer inlets, respectively. Measurements are conducted by varying air flow rate and equivalence ratio (Φ), in which a steady tubular flame can only be obtained below Φ = 0.35, above which the flame becomes unsteady. (2) N2 is adopted as the diluent in both H2 and O2 streams. By adding N2 in the fuel stream to approach the same mean injection velocity as that of N2 and O2 mixture in the oxidizer inlet, fuel/oxidizer mixing is much enhanced, and a steady tubular flame has been achieved at Φ = 0.5. Then the oxygen content in the overall mixture of N2 and O2 is gradually reduced from 0.21 to investigate the combustion characteristics. Flame structure, lean extinction limit, flame stability and laminar burning velocity as well as temperature are investigated under various oxygen contents and equivalence ratios. The results provide a useful guide to the safe operation of hydrogen combustion in the rapidly mixed tubular flame burner.
Helping Teams Expand the Breadth of Their Solution Space Through Product Dissection: A Simulation Based Investigation
Authors: Alsager Alzayed Mohammad , McComb Christopher , Hunter Samuel T. , Miller Scarlett R.
Published: November 2018

Product dissection has been highlighted as an effective means of interacting with example products in order to produce creative outcomes. While product dissection is often conducted as a team in engineering design education as a component of larger engineering design projects, the research on the effectiveness of product dissection activities has been primarily limited to individuals. Thus, the goal of this study was to investigate the impact of the type(s) of product dissected in a team environment on the breadth of the design space explored and the underlying influence of educational level on these effects. This was accomplished through a computational simulation of 7,000 nominal brainstorming teams generated by a statistical bootstrapping technique that accounted for all possible team configurations. Specifically, each team was composed of four team members based on a design repository of 463 ideas generated by first-year and senior engineering design students after a product dissection activity. The results of the study highlight that simulated senior engineering design teams explored a larger solution space than simulated first-year teams and that dissecting different types of products allowed for the exploration of a larger solution space for all of the teams. The results also showed that dissecting two analogically far and two simple products was most effective in expanding the solution space for simulated senior teams. The findings presented in this study can lead to a better understanding of how to most effectively deploy product dissection modules in engineering design education in order to maximize the solution space explored.
Design of Planar 1-DOF Cam-Linkages for Lower-Limb Rehabilitation via Kinematic-Mapping Motion Synthesis Framework
Authors: Zhao Ping , Zhu Lihong , Li Xiangyun , Zi Bin
Published: November 2018

When designing linkage mechanisms for motion synthesis, many examples have shown that the optimal kinematic constraint on the task motion contain too large deviation to be approximately viewed as a single rotational or translational pair. In this paper we seek to adopt our previously established motion synthesis framework for the design of cam-linkages for a more accurate realization, while still maintaining a one-DOF mechanism. To determine a feasible cam to lead through the task motion, first a kinematic constraint is identified such that a moving point on the given motion traces a curve that is algebraically closest to a circle or a line. This leads to a cam contour that is simple and smooth to avoid the drawbacks of cam mechanisms. Additional constraints could also be imposed to specify the location and/or size of the cam-linkages. An example of the design of a lower-limb rehabilitation device has been presented in the end of this paper to illustrate the feasibility of our approach. It is shown that our design could lead the user through a normal walking motion.
Conservative Error Space Estimation of 3-DoF Planar Parallel Mechanisms
Authors: Ding Jianzhong , Lu Shengnan , Da Ting , Wang Chunjie , Chirikjian Gregory S.
Published: November 2018

This article develops a geometric method to estimate the error space of 3-DoF planar mechanisms with the Minimum Volume Ellipsoid Enclosing (MVEE) approach. Both the joint clearance and input uncertainty are considered in this method. Three typical planar parallel mechanisms are used to demonstrate. Error spaces of their serial limbs are analyzed, respectively. Thereafter, limb-error-space-constrained mobility of manipulator, namely, the manipulator error space is analyzed. MVEE method has been applied to simplify the constraint modeling. A closed-form expression for the manipulator error space is derived. The volume of the manipulator error space is numerically estimated. The study approached in this paper develops a geometric error analysis method of parallel mechanisms with clear algebraic expressions. Moreover, far fewer forward kinematics computations have been performed in the proposed method than in the widely used interval analysis method. Although the estimated error space is larger than that in practice, due to the enclosing ellipses enlarge the regions of limb error space, the method has attractive advantage of high computational efficiency.
Flexure-Pivot Oscillator Restoring Torque Nonlinearity and Isochronism Defect
Authors: Thalmann E. , Kahrobaiyan M. H. , Henein S.
Published: November 2018

Flexure pivot based oscillators can advantageously replace the hairspring and balance wheel, the time base used in mechanical watches, by drastically reducing friction. However, flexure pivots have drawbacks including gravity sensitivity and restoring torque nonlinearity. In previous work, we introduced a novel gravity insensitive flexure pivot (GIFP) to solve the problem of gravity sensitivty, but no analytical formulation for the restoring torque nonlinearity was found. In this paper, we use numerical simulation to find an empirical expression for restoring torque nonlinearity. We use this expression to find an analytical formula for the rotational stiffness of GIFP. This formula gives an explicit relationship between restoring torque nonlinearity and the isochronism of the corresponding harmonic oscillator. The results also apply to the widely used generalized cross-spring pivot.
Modelling and Simulation of a Robotic System for Lower Limb Rehabilitation
Authors: Gherman Bogdan , Birlescu Iosif , Tucan Paul , Vaida Calin , Pisla Adrian , Pisla Doina
Published: November 2018

As the life span increases and the availability of physicians becomes more and more scarce, robotic rehabilitation for post-stroke patients becomes more and more demanding, especially due to the repeatability character of the rehabilitation exercises. Both lower and upper limb rehabilitation using robotic systems have proved to be very successful in different stages of the rehabilitation process, but only a few address the immediate (critical) post-stroke phase, especially when the patient is hemiplegic and is unable to stand. The paper presents the kinematic modelling, singularity analysis and gait simulation for a new 4-DOF parallel robot named RECOVER used for lower limb rehabilitation for bedridden patients. The robotic system has been designed for the mobilization of the lower limb, namely the following motions: the hip and knee flexion and the plantar adduction/abduction and flexion/dorsiflexion. The kinematics has been studied and the singularity configurations have been determined to achieve a failsafe rehabilitation robot. Numerical simulations prove that the system can be used for gait training exercises in safe conditions.
Confidently Exploring the Solution Space: The Within-Subject Effects of Product Dissection on Design Variety and Creative Self-Efficacy
Authors: Starkey Elizabeth M. , Alsager Alzayed Mohammad , Hunter Samuel T. , Miller Scarlett R.
Published: November 2018

Product dissection is a popular educational tool in engineering design due to its ability to help students understand the components and sub-components of a product, provide inspiration for new design ideas, and aid in product redesign. While prior research has investigated how dissecting a product before idea generation impacts the creative output of the ideation session, these studies failed to look at the types of ideas generated before dissection or how the type of product dissected impacts this. In addition, few studies have looked at how creative self-efficacy (CSE), or one’s belief in their creative ability, is influenced by these intervention activities. Thus, the current study was developed to respond to these research voids through an exploratory study with engineering design students. The results of the study suggest that virtual dissection helps students generate a larger variety of ideas after the activity at the physical principle, working principle, and embodiment levels, and that the complexity of the dissected product impacts variation at the embodiment level. In addition, CSE was not affected by the dissection activity. These results strongly support the utilization and implementation of dissection practices in engineering education as a means for aiding students in the expansion of the solution space in the early stages of design. They also bring attention to the need to explore the exact cause-effect relationship between innovation interventions and student confidence gains in their creative abilities.
Expensive Black-Box Model Optimization via a Gold Rush Policy
Authors: Isaac Benson , Allaire Douglas
Published: November 2018

The optimization of expensive black-box models is a challenging task owing to the lack of analytic gradient information and structural information about the underlying function, and also due to the sheer computational expense. A common approach to tackling such problems is the implementation of Bayesian global optimization techniques. However, these techniques often rely on surrogate modeling strategies that endow the approximation of the underlying expensive function with nonexistent features. Further, these techniques tend to push new queries away from previously queried design points, making it difficult to locate an optimum point that rests near a previous model evaluation. To overcome these issues, we propose a gold rush policy that relies on purely local information to identify the next best design alternative to query. The method employs a surrogate constructed pointwise, that adds no additional features to the approximation. The result is a policy that performs well in comparison to state of the art Bayesian global optimization methods on several benchmark problems. The policy is also demonstrated on a constrained optimization problem using a penalty method.
An Experimental and Theoretical Investigation of Double Resonance Activation in Electrostatic MEMS Resonators
Authors: Hasan Mohammad H. , Ouakad Hassen M. , Jaber Nizar R. , Al Hafiz Md Abdullah , Alsaleem Fadi , Younis Mohammad
Published: November 2018

Electrostatic micro-electro-mechanical-system (MEMS) devices show great potential in a variety of applications such as sensing and actuation; however, they are hindered by their high input voltage requirement. Double resonance excitation, which activates the system’s mechanical and electrical resonances simultaneously, was recently demonstrated experimentally to alleviate this problem. In this work, we present a mathematical model, based on the Euler Bernoulli beam model coupled with a circuit model, to simulate double resonance in MEMS devices and to shed light more onto the previously published experimental data. We show good agreement between the theoretical simulation and experimental data when the electrical resonance frequency band is sufficiently high.
Experimental Exploration of Schallamach Waves and Self-Excitation in a Belt-Drive System
Authors: Wu Yingdan , Varenberg Michael , Leamy Michael J.
Published: November 2018

We study the dynamic behavior of a belt-drive system to explore the effect of operating conditions and system moment of inertia on the generation of waves of detachment (i.e., Schallamach waves) at the belt-pulley interface. A self-excitation phenomenon is reported in which frictional fluctuations serve as harmonic forcing of the pulley, leading to angular velocity oscillations which grow in time. This behavior depends strongly on operating conditions (torque transmitted and pulley speed) and system inertia, and differs between the driver and driven pulleys. A larger net torque applied to the pulley generally yields more remarkable stick-slip oscillations with higher amplitude and lower frequency. Higher driving speeds accelerate the occurrence of stick-slip motion, but have little influence on the oscillation amplitude. Contrary to our expectations, the introduction of flywheels to increase system inertia amplified the frictional disturbances, and hence the pulley oscillations. This does, however, suggest a way of facilitating their study, which may be useful in follow-on research.
A Spatial Grammar Method for the Computational Design Synthesis of Virtual Soft Robots
Authors: van Diepen Merel , Shea Kristina
Published: November 2018

Soft robots are intrinsically compliant, which makes them suitable for interaction with delicate objects and living beings. The vast design space and the complex dynamic behavior of the elastic body of the robots make designing them by hand challenging, often requiring a large number of iterations. It is thus advantageous to design soft robots using a computational design approach that integrates simulation feedback. Since locomotion is an essential component in many robotic tasks, this paper presents the computational design synthesis of soft, virtual, locomotion robots. Methods used in previous work give little insight into and control over the computational design synthesis process. The generated solutions are also highly irregular and very different to hand-designed solutions. Also, the problem requirements are solely modeled in the objective function. Here, designs are generated using a spatial grammar with a rule set that is deduced from known locomotion principles. Spatial grammars make it possible to define the type of morphologies that are generated. The aim is to generate gaits based on different locomotion principles, e.g. walking, hopping and crawling. By combining a spatial grammar with simulated annealing, the solution space is searched for locomotive designs. The designs are simulated using a mass-spring model with stable self-collision so that all generated designs can be evaluated. The resulting virtual designs exhibit a large variety of expected and unexpected gaits. The grammar is analyzed to understand the generation process and assess the performance. The main contribution of this research is modeling of some of the results in the spatial grammar rather than the objective function. Thus, the process is guided towards a class of designs with extremities for locomotion, without having to define the class explicitly. Further, the simulation approach is new and results in a stable method that accounts for self-collision.
Systematic Redesign of Air Compressor for Noise Reduction: A Case Study
Authors: Moylan Justin T. , O’Shields Steven T. , Summers Joshua D. , Wagner John R.
Published: November 2018

Portable electric air compressors produce noise which can be a nuisance or even hazardous to persons in the vicinity; therefore, noise reduction of these compressors is a desired design evolution. An experimental setup was developed to measure the sound and vibration of existing air compressors and to test new prototypes. The design of a quiet air compressor was performed in four stages: 1) compressor teardown and benchmarking, 2) noise source identification and isolation, 3) development of a morphological chart for quiet noise sources, and 4) integrated solution selection and testing. The systematic approach and results for each of these stages will be discussed. Two redesigned solutions were developed and measured to be approximately 65% quieter than the previous unmodified compressor. The benefits of using a specific design procedure to reverse engineer, test, and develop new concepts are discussed.
Preliminary User Study on Design Heuristics for Additive Manufacturing
Authors: Blösch-Paidosh Alexandra , Shea Kristina
Published: November 2018

Additive manufacturing (AM) has unique capabilities when compared to traditional manufacturing, such as shape, hierarchical, functional, and material complexity, a fact that has fascinated those in research, industry, and the media for the last decade. Consequently, designers would like to know how they can incorporate AM’s special capabilities into their designs, but are often at a loss as to how to do so. Design for Additive Manufacturing (DfAM) methods are currently in development but the vast majority of existing methods are not tailored to the needs and knowledge of designers in the early stages of the design a process. The authors have previously derived 29 design heuristics for AM. In this paper, the efficacy of these heuristics is tested in the context of a re-design scenario with novice designers. The preliminary results show that the heuristics positively influence the designs generated by the novice designers. Analysis of the use of specific heuristics by the participants and future research to validate the impact of the design heuristics for additive manufacturing with expert designers and in original design scenarios is planned.
Modeling and Characteristics Analysis on Hydraulic Operating Mechanism for Ultra-High Voltage Circuit Breakers
Authors: Liang Liang , Lai Qiwei , Teng Lin , Yang James , Ma Yanzhao , Wu Shijing
Published: November 2018

Compared with regular mechanical operating mechanisms, the hydraulic operating mechanism has widespread industrial applications in large hydraulic systems such as ultra-high voltage circuit breakers due to its requirements of fast response, high flow rate and instantaneous super power. This paper intends to analyze the characteristics of hydraulic operating mechanism for ultra-high voltage circuit breakers from a systemic perspective. A comprehensive mathematical model of hydraulic operating mechanism system including pipelines and all valves has been developed. Meanwhile, experiments focusing on the dynamic and pressure characteristics of hydraulic operating mechanism are conducted to validate simulation models. The proposed research methods can provide significant theoretical guidance and practical value for further study of hydraulic operating mechanism of high standard hydraulic system like ultra-high voltage circuit breakers.
Experimental Apparatus for Assessing the Nonlinear Dynamics of Engine Restart and Shutdown
Authors: Wilbanks Justin , Leamy Michael J.
Published: November 2018

An experimental apparatus has been designed and fabricated to assess the nonlinear dynamics of internal combustion engine (ICE) restart and shutdown. The final objective for the apparatus is to validate the application of two-scale command shaping (TSCS) for reduction of unwanted vibrations during ICE restart. The apparatus allows user-specified torque profiles to be applied to a three-cylinder ICE from an electric machine (EM). In turn, the apparatus can measure oscillations in the driveline and chassis, which will ultimately determine the efficacy of TSCS as applied to engine restart. Preliminary results from the apparatus document its ability to measure the unwanted oscillations in the response of the powertrain during ICE restart and shutdown. The apparatus is also expected to provide data, combined with parameter estimation techniques, to determine otherwise uncertain parameters associated with the ICE and EM.
Modeling Large Deformation Impact Dynamics for Legged Microrobot Locomotion: A Preliminary Formulation
Authors: Surya Prakash Nikhil Potu , Oldham Kenn
Published: November 2018

A finite element dynamic model is developed to better understand impact events during large amplitude dynamics of a compliant, elastic-legged small-scale robot. The proposed motion of the robot would be achieved as a result of impulse forces generated from the forced collision of piezoelectrically-actuated, beam-like legs with the ground. The nominal robot leg is a prismatic continuous structure with uniform density, cross-sectional area and moment of inertia. Dynamic modeling in this work attempts to manage the non-negligible motion of the actuated beam tip in its axial direction at impact when large bending deformations are excited, which complicates prior analysis methods. For the micro-robot, this motion is proposed to be exploited as a means to produce locomotion in the horizontal direction, and hence must be accounted for. Finite element analysis approaches are adapted for the micro-robotic circumstances. Preliminary results are presented for the scenario of large deformation, unforced dynamics with impact, tested using centimeter-scale mock-ups for future thin-film based micro-robots. Needs and opportunities for further validation are briefly discussed.
Test Frame Design for the Characterization of Additive Manufacturing Compliant Materials
Authors: Fry Sean T. , Turner Cameron J.
Published: November 2018

This work presents a design of a 6 degree of freedom (DOF) robotic test frame designed to provide multiple and combined loading scenarios for additive manufacturing (AM) materials. The need is to provide a more in-depth look into the material properties of nonlinear anisotropic materials as traditional uniaxial or biaxial test frames have been shown to be inefficient in providing accurate material property values. With the application of surrogate models with General Purpose Graphics Processing (GPGPU) computing, “real-time” characterization is achievable. The work provided is a next generation 6 DOF test frame designed to reducing costs, increasing workspace, and reducing overall size over previous designs.
Understanding the Effect of Task Complexity and Problem-Solving Skills on the Design Performance of Agents in Systems Engineering
Authors: Safarkhani Salar , Bilionis Ilias , Panchal Jitesh H.
Published: November 2018

Systems engineering processes coordinate the efforts of many individuals to design a complex system. However, the goals of the involved individuals do not necessarily align with the system-level goals. Everyone, including managers, systems engineers, subsystem engineers, component designers, and contractors, is self-interested. It is not currently understood how this discrepancy between organizational and personal goals affects the outcome of complex systems engineering processes. To answer this question, we need a systems engineering theory that accounts for human behavior. Such a theory can be ideally expressed as a dynamic hierarchical network game of incomplete information. The nodes of this network represent individual agents and the edges the transfer of information and incentives. All agents decide independently on how much effort they should devote to a delegated task by maximizing their expected utility; the expectation is over their beliefs about the actions of all other individuals and the moves of nature. An essential component of such a model is the quality function, defined as the map between an agent’s effort and the quality of their job outcome. In the economics literature, the quality function is assumed to be a linear function of effort with additive Gaussian noise. This simplistic assumption ignores two critical factors relevant to systems engineering: (1) the complexity of the design task, and (2) the problem-solving skills of the agent. Systems engineers establish their beliefs about these two factors through years of job experience. In this paper, we encode these beliefs in clear mathematical statements about the form of the quality function. Our approach proceeds in two steps: (1) we construct a generative stochastic model of the delegated task, and (2) we develop a reduced order representation suitable for use in a more extensive game-theoretic model of a systems engineering process. Focusing on the early design stages of a systems engineering process, we model the design task as a function maximization problem and, thus, we associate the systems engineer’s beliefs about the complexity of the task with their beliefs about the complexity of the function being maximized. Furthermore, we associate an agent’s problem solving-skills with the strategy they use to solve the underlying function maximization problem. We identify two agent types: “naïve” (follows a random search strategy) and “skillful” (follows a Bayesian global optimization strategy). Through an extensive simulation study, we show that the assumption of the linear quality function is only valid for small effort levels. In general, the quality function is an increasing, concave function with derivative and curvature that depend on the problem complexity and agent’s skills.
How Engineering Design Students’ Creative Preferences and Cognitive Styles Impact Their Concept Generation and Screening
Authors: Heininger Katie , Chen Hong-En , Jablokow Kathryn , Miller Scarlett R.
Published: November 2018

The flow of creative ideas throughout the engineering design process is essential for innovation. However, few studies have examined how individual traits affect problem-solving behaviors in an engineering design setting. Understanding these behaviors will enable us to guide individuals during the idea generation and concept screening phases of the engineering design process and help support the flow of creative ideas through this process. As a first step towards understanding these behaviors, we conducted an exploratory study with 19 undergraduate engineering students to examine the impact of individual traits, using the Preferences for Creativity Scale (PCS) and Kirton’s Adaption-Innovation inventory (KAI), on the creativity of the ideas generated and selected for an engineering design task. The ideas were rated for their creativity, quality, and originality using Amabile’s consensual assessment technique. Our results show that the PCS was able to predict students’ propensity for creative concept screening, accounting for 74% of the variation in the model. Specifically, team centrality and influence and risk tolerance significantly contributed to the model. However, PCS was unable to predict idea generation abilities. On the other hand, cognitive style, as measured by KAI, predicted the generation of creative and original ideas, as well as one’s propensity for quality concept screening, although the effect sizes were small. Our results provide insights into individual factors impacting undergraduate engineering students’ idea generation and selection.
Simulating Hypervelocity Impact and Material Failure in Glass
Authors: Birnbaum Andrew J. , Steuben John C. , Iliopoulos Athanasios P. , Michopoulos John G.
Published: November 2018

Simulating hypervelocity impact introduces a host of complexities due to inherent strain, pressure and strain rate sensitivities. Brittle materials, and glasses in particular, exhibit significant deviations from their respective quasi-static responses, displaying permanent densification, gradual softening, and significant variation in response depending on the degree of material damage. This work seeks to examine the evolution of material failure due to hypervelocity impact of a spherical steel projectile in to a soda-lime target plate over a range of impact velocities via the utilization of a scalable, explicit finite element code, Velodyne, and a high strain rate, brittle material model. It is shown that, by analyzing both the evolutionary instantaneous and accumulated failure behaviors, the resulting performance is profoundly effected by target/projectile geometries, as well as the complex behaviors observed with respect to shock propagation, reflection and interference.
A Preliminary Fluid Dynamic Model of a Vacuum Micro-Gripper With Integrated Release System
Authors: Ruggeri Serena , Fontana Gianmauro , Ghidoni Antonio , Morelli Alessandro , Legnani Giovanni , Lezzi Adriano Maria , Fassi Irene
Published: November 2018

The miniaturization of an increasing number of complex hybrid micro-products is currently leading the development of several micro-components to manipulate and assemble, meeting various specifications related to the objects properties and the planned task. However, at the micro-scale, further challenges derive from the effects of surface forces between object and micro-gripper that have to be overcome for an effective and successful manipulation. When contact micro-grippers are used, specific solutions to support the release phase are needed. Further developments and novel tools should be developed for vacuum micro-grippers to actively release the components reliably and precisely. In this context, this paper presents a vacuum micro-gripper with an automatic releasing system able to overcome the adhesive forces simply and effectively. The paper reports the results of a preliminary computational fluid dynamics analysis and the development of a numerical model able to represent the main gripper characteristics and derive a first design procedure.
Design of a Passive, Shear-Based Rotary Hydraulic Damper for Single-Axis Prosthetic Knees
Authors: Arelekatti V. N. Murthy , Petelina Nina T. , Johnson W. Brett , Winter Amos G. , Major Matthew J.
Published: November 2018

With over 30 million people worldwide in need of assistive devices, there is a great need for low-cost, high performance prosthetic technologies in the developing world. A majority of the hydraulic dampers used in prosthetic knee designs are highly specialized, expensive, require regular maintenance, and are incompatible for use with low-cost, single-axis prosthetic knees popular in developing countries. In this study, optimal damping coefficients were computed based on a theoretical analysis of gait, specifically during the transition from the stance to swing phase of human walking when a large damping torque is needed at the knee. A novel rotary hydraulic damper prototype was designed using high-viscosity silicone oil and a concentric meshing of fins for shearing the oil. The prototype was validated experimentally to provide the desired damping torque profile. For preliminary, user-centric validation of the prototype, a gait study on one above-knee amputee in India was conducted with four different damping magnitudes. Feedback from the subject validated the optimal damping torque magnitude predicted for minimizing gait deviations and for enabling able-bodied knee kinematics. The new rotary hydraulic damper design is novel, passive, and compatible with low-cost, single-axis knee prostheses.
Project Recommendation for Mass Collaboration Design Networks
Authors: Ball Zachary , Lewis Kemper
Published: November 2018

Mass collaboration within the design engineering process supports the inclusion of unique perspectives when working on complex problems. Increasing the number of individuals providing input and support into these perplexing challenges can increase innovation, decrease product development times and provide solutions that truly encompass the needs of the market. One of the greatest challenges within mass collaboration engineering projects is the organization of individuals within these large design efforts. Understanding which projects would most effectively benefit from additional designers or contributors is paramount to supporting mass collaboration design networks. Within such networks, there exists a large number of contributors, as well as, a large pool of potential challenges. Matching individuals with the challenges that they can provide the greatest benefit to, or building a team of individuals for newly developed challenges requires the consideration of previous performance and an understanding of individual competencies and design abilities. This work presents a framework which recommends individual project placement based on individual abilities and the project requirements. With this work a pool of individuals and potential projects are simulated and the application of a hybrid recommender system is explored. Overall it was found that recommended team compositions greatly outperform the baseline team development, most notably as greater consideration is placed on collaborative recommendations.
Selective Wave Filtering in Time-Modulated Elastic Metamaterials
Authors: Xia Yiwei , Trainiti Giuseppe , Erturk Alper , Ruzzene Massimo
Published: November 2018

We implement periodic stiffness time-modulation in a beam with piezoelectric patches and switchable shunted negative capacitance. The shunted negative capacitance circuits, connected in series with each piezoelectric patch through a switch, soften the structure. By alternatively opening and closing the switch, the beam’s stiffness effectively oscillates periodically between two values. We present a simplified theoretical model of time-periodic beams and describe the occurrence of flat bands in the dispersion diagrams. We show that a narrowband reflection from a time-modulated domain can be obtained for a broadband incident wave, hence qualifying the modulated domain as a single-port system with tunable response. We validate our theoretical findings by comparing time-domain simulations with experimental measurements of transient wavefields through scanning Doppler laser vibrometry.
Control of Process Settings for Large-Scale Additive Manufacturing With Sustainable Natural Composites
Authors: Vijay Yadunund , Sanandiya Naresh D. , Dritsas Stylianos , Fernandez Javier G.
Published: November 2018

We present an additive manufacturing system for 3D printing large-scale objects using natural bio-composite materials. The process, affine to the Direct Ink Writing method, achieves build rate of 2.5cm3/s using a precision dispensing unit mounted on an industrial six-axis robot. During deposition the composite is wet and exhibits thixotropy. As it loses moisture it hardens and shrinks anisotropically. This paper highlights work on controlling the process settings to print filaments of desired dimensions while constraining the operating point to a region where tensile strength is maximum while shrinkage is minimum. Response surface models relating the controllable process settings such as Robot Linear Velocity, Material Feed Rate and Nozzle Offset, to the geometric and physical properties of an extruded filament, are obtained through Face-centered Central Composite Designed experiments. Unlike traditional applications of this technique which involve identifying a fixed optimal operating point, we use these models to first uncover the possible dimensions of a filament that can be obtained within operating boundaries of our system. Process setting predictions are then made through multi-objective optimization of the mathematical models. An interesting outcome of our study is the ability to produce filaments of different shrinkage and tensile strength properties, by solely changing process settings. As a follow up, we identify the optimal lateral overlap and inter-layer spacing parameters to define toolpaths to print 3D structures. If unoptimized, the material’s anisotropic shrinkage and non-linear compression characteristics cause severe delamination, cross-sectional tapering and warpage. Lastly, we show the linear scalability of our shrinkage model in 3D space which allows us to suitably compensate toolpaths to significantly improve dimensional accuracy of 3D printed artifacts.
Using “Why and How” to Tap Into Novice Designers’ Method Selection Mindset
Authors: Poreh Danielle , Kim Euiyoung , Vasudevan Varna , Agogino Alice
Published: November 2018

Despite the growing utilization of human-centered design, both in academia and industry, there is lack of pedagogical materials that support context-based design method selection. When used properly, design methods are linked to successful outcomes in the design process, but with hundreds of design methods to select from, knowing when and how to use a particular method is challenging. Selecting the appropriate design method requires a deep understanding of the project context. Cultivating a selection methodology that is more contextually aware, equips students with the tools to apply the most appropriate methods to their future academic and industry projects. Using theDesignExchange knowledge platform as a teaching material, we discuss a summer design course at the University of California at Berkeley that encourages students to choose design methods rather than the instructors giving a set list. The findings illustrate that when given the task to select a method, students exhibit contextually-aware method selection mindsets.
Design of a Variable-Mobility Linkage Using the Bohemian Dome
Authors: López-Custodio P. C. , Dai J. S.
Published: November 2018

The properties of the Bohemian dome are studied and it is found that for a particular type of Bohemian dome two different parameterizations based on the translation of circles can be obtained for the same surface, therefore, two different hybrid kinematic chains can be designed to generate the same Bohemian dome. These surface generators are reconfigurable and can generate two different surfaces each. Parameterizations for the secondary surfaces are obtained and studied. These hybrid kinematic chains are used to design a kinematotropic linkage with a total of 27 motion branches in its configuration space. The singularities in the configuration space are also determined using the properties of the surfaces. The resultant linkage offers an explanation of Wholhart’s queer-square linkage other than paper folding.

The relationship between the properties of self-intersections in generated surfaces and the configuration space of the generator linkage is studied for the first time leading to the description of motion branches related to self-intersections of generated surfaces.
Extending Lead User Theory to Participatory Co-Design: A Case Study in a Base of the Pyramid Context
Authors: Ross Rachel , Rouen Katherine , Austin-Breneman Jesse
Published: November 2018

New product development (NPD) presents a number of challenges to engineering teams designing for the base of the economic pyramid (BoP). Existing design methods may not be appropriate for the unique operating context. In response to these differences, product design teams and researchers have turned to participatory design as an approach to designing with people in emerging communities to address the main failure mode identified in past BoP projects, namely the misidentification of user needs. Past research and experience has demonstrated that identifying users to engage in participatory co-design is challenging and effectively selecting the right user is critical for a successful project. This study examines whether Urban and Von Hippel’s Lead User Theory could be effective in NPD processes for BoP markets. This work explores extending Lead User Theory to participatory co-design projects in a BoP context using a case study of an improved cook stove design in Gujarat, India. A comparison of themes drawn from qualitative analysis of stakeholder interviews to Von Hippel’s Lead User Theory illustrates possible changes to the lead user concept to account for the BoP context. Results suggest that being “ahead of trend” is not critical to participatory co-design success. An extended model which includes an expanded definition of expected benefit, design communication skills, and access to user preferences through a social network could help identify “lead users” for participatory co-design projects in BoP contexts.
Enriched Analytical Solutions for Additive Manufacturing Modeling and Simulation
Authors: Steuben John C. , Birnbaum Andrew J. , Iliopoulos Athanasios P. , Michopoulos John G.
Published: November 2018

Additive Manufacturing (AM) is an increasingly widespread family of technologies for the fabrication of objects based on successive depositions of mass and energy. A strong need for modeling and simulation tools for AM exists, in order to predict thermal histories, residual stresses, microstructure, and various other aspects of the resulting components. In this paper we explore the use of analytic solutions to model the thermal aspects of AM, in an effort to achieve high computational performance and enable “in the loop” use for feedback control of AM processes. It is shown that the utility of existing analytical solutions is limited due to their underlying assumption of a homogeneous semi-infinite domain. These solutions must therefore be enriched from their exact form in order to capture the relevant thermal physics associated with AM processes. Such enrichments include the handling of strong nonlinear variations in material properties, finite non-convex solution domains, behavior of heat sources very near boundaries, and mass accretion coupled to the thermal problem. The enriched analytic solution method (EASM) is shown to produce results equivalent to those of numerical methods which require six orders of magnitude greater computational effort.