bluuebunny/crossref_metadata_2025 huggingface dataset:
Exploring the Use of a Full Factorial Design of Experiment to Study Design Briefs for Creative Ideation
Authors: Kang Kai Siang Jacob , Chia Pei Zhi , Koronis Georgios , Silva Arlindo
Published: November 2018

Coming at the start of the design process, the information contained in design briefs influences the framing of the designer’s perspectives of the design problem and the creativity of the design outcomes. This study investigates four types of information in design briefs: quantitative requirements, a visual example (video), a physical example and contextual information. Creativity studies typically use a one-variable-at-a-time approach that cannot collect data on interaction effects, thus this study explores the use of a full factorial Design of Experiment to study both the main effects and the two-way interaction effects. Creativity is measured according to three metrics: novelty, appropriateness, and usability. The results suggest that providing no additional information in the design brief results in high novelty scores and low appropriateness and usability scores, the main effect of providing a video example results in high appropriateness and usability scores but low novelty scores, and physical-contextual briefs have reasonably high novelty and usability scores. Methodological limitations and suggestions for improvements are discussed extensively.
Identifying Design Interventions in Cities for Urban Sustainability
Authors: Arora Mohit , Raspall Felix , Silva Arlindo
Published: November 2018

Cities have been the focus of recent sustainability and climate change mitigation efforts primarily because of unprecedented urban growth and ever-increasing resources consumption. A worrying trend has been the ever-decreasing life of buildings in cities because of premature building obsolescence. Premature building obsolescence has been cited as the major driver of demolition waste which accounts for more than 40% of total waste generated annually. This waste stream poses a bigger challenge as the pressure on natural resources increases with urban growth. A traditional way of looking at the urban sustainability has been from the perspective of the environmental sciences and waste management methods. Analyzing urban areas with design science perspectives could provide novel insights to improve existing resource consumption patterns and transform sustainability growth in cities. This study focuses on the problem of demolition waste arising from the premature building obsolescence in cities. It applies a design research methodology framework for identifying existing problems associated with demolition waste and generating strategies to transform cities into more sustainable urban systems. In the problem clarification phase, a detailed literature review was supported with stakeholder’s interviews to identify the state-of-art for building demolition process and demolition waste. Research was further extended to descriptive study-I phase to carry out a demolition case study and generate support tools to enable transformation in the existing scenario for achieving a desired state. Singapore, a dense city state of South-East Asia has been taken as a case study in this research. Results show that applying design research methods could help open-up a new dimension to solve urban sustainability challenge for built environment. It highlights that material reuse could lead to significant improvement in the built environment sustainability but the challenge associated with realization of material reuse practice needs to be addressed. Descriptive study-I concludes with the strategies on creating a reuse market through entrepreneurial innovation and an alternative material supply chain of secondary materials for regional housing demand. These results highlight the role of design research methods for tackling complex systems level problems in cities.
Design for Additive Manufacturing of Cellular Compliant Mechanism Using Thermal History Feedback
Authors: Khurana Jivtesh , Hanks Bradley , Frecker Mary
Published: November 2018

With growing interest in metal additive manufacturing, one area of interest for design for additive manufacturing is the ability to understand how part geometry combined with the manufacturing process will affect part performance. In addition, many researchers are pursuing design for additive manufacturing with the goal of generating designs for stiff and lightweight applications as opposed to tailored compliance. A compliant mechanism has unique advantages over traditional mechanisms but previously, complex 3D compliant mechanisms have been limited by manufacturability. Recent advances in additive manufacturing enable fabrication of more complex and 3D metal compliant mechanisms, an area of research that is relatively unexplored. In this paper, a design for additive manufacturing workflow is proposed that incorporates feedback to a designer on both the structural performance and manufacturability. Specifically, a cellular contact-aided compliant mechanism for energy absorption is used as a test problem. Insights gained from finite element simulations of the energy absorbed as well as the thermal history from an AM build simulation are used to further refine the design. Using the proposed workflow, several trends on the performance and manufacturability of the test problem are determined and used to redesign the compliant unit cell. When compared to a preliminary unit cell design, a redesigned unit cell showed decreased energy absorption capacity of only 7.8% while decreasing thermal distortion by 20%. The workflow presented provides a systematic approach to inform a designer about methods to redesign an AM part.
A Variant Nonlinear Energy Sink for Vibration Suppression and Energy Harvesting
Authors: Li Xiaolin , Liu Kefu , Xiong Liuyang , Tang Lihua
Published: November 2018

In this paper a variant nonlinear energy sink (NES) is developed for the purpose of simultaneous vibration suppression and energy harvesting in a broad frequency band. The NES consists of a cantilever beam attached by a mass at its free end and a pair of so-called double-stop blocks. The beam is formed by a piezoelectric energy harvester and a thin steel plate. It is placed between the double-stop blocks. The constraint of the double-stop blocks forces the beam to deflect nonlinearly. First, the developed apparatus is described. Subsequently, system modeling and parameter identification are addressed. The performance of the apparatus under transient responses is examined through both numerical simulation and experimental study. The results show that the proposed apparatus behaves similarly as the NES with the following features: 1:1 resonance, targeted energy transfer, initial energy dependence, etc.
Recovering a Rotation Matrix From Three Direction Cosines
Authors: Xu Mengdi , Chirikjian Gregory S.
Published: November 2018

In this paper, we propose a new parameterization method to represent rotation matrices using the angles ϕ→ recovered from the three direction cosines that lie on the diagonal. The map from the possible configuration space of the new variable ϕ→ to the solid ball model in axis-angle coordinates is constructed. We also introduce a bi-invariant metric and two left-invariant metrics for measuring the distance in configuration space which could be the foundation for path planning in ϕ→ space. We further analyze the Jacobian matrix and singularities to better understand the manipulability.
Games and Exercises for Teaching and Research: Exploring How Learning Varies Based on Fidelity and Participant Experience
Authors: Gralla Erica , Szajnfarber Zoe
Published: November 2018

It has long been recognized that games are useful in engineering education, and more recently they have also become a common setting for empirical research. Games are useful for both teaching and research because they mimic aspects of reality and require participants to reason within that realistic context, and they allow researchers to study phenomena empirically that are hard to observe in reality. This paper explores what can be learned by students and by researchers, based on the authors’ experience with two sets of games. These games vary in both the experience level of the participants and the “fidelity” or realism of the game itself. Our experience suggests that what can be learned by participants and by researchers depends on both these dimensions. For teaching purposes, inexperienced participants may struggle to connect lessons from medium-fidelity games to the real world. On the other hand, experienced participants may learn more from medium-fidelity games that provide the time and support to practice and reflect on new skills. For research purposes, high-fidelity games are best due to their higher ecological validity, even with inexperienced participants, although experienced participants may enable strong validity in medium-fidelity settings. These findings are based on experience with two games, but provide promising directions for future research.
A Flexible Chain Proposal for Winch Based Point Absorbers
Authors: Andersson Kjell , Hagnestål Anders , Sellgren Ulf
Published: November 2018

Ocean wave power is a promising renewable energy source for future energy production. It has however been difficult to find a cost-effective solution to convert the wave energy into electricity. The harsh marine environment and the fact that wave power is delivered with high forces at low speeds makes design of durable mechanical structures and efficient energy conversion challenging. The dimensioning forces strongly depend on the wave power concept, the Wave Energy Converter (WEC) implementation and the actual Power Take-Off (PTO) system.

A WEC using a winch as a Power Take-Off system, i.e. a Winch Based Point Absorber (WBPA), could potentially accomplish a low Levelized Cost Of Energy (LCOE) if a key component — a low-cost, durable and efficient winch that can deal with high loads — can be developed.

A key problem for achieving a durable winch is to find a force transmitting solution that can deal with these high loads and handle up to 80 million cycles. In this article we propose a design solution for a force transmitting chain in a WBPA system where elastomeric bearings are used as a means to achieve the relative motion between the links in the chain. With this solution no sliding is present and the angular motion is achieved as a deformation in the elastomeric bearing when the chain is winded on a drum.

The link was designed primarily to minimize the number of joints in the chain: Thereby the maximum allowed relative angle between the links when rolled up over the drum should be as large as possible within practical limits. The angle is to be handled by the elastomeric bearing. A detailed strength analysis of the link has been performed as well as topology optimization to increase the strength to weight ratio.

A test rig for a first proof of concept testing has been developed and the first preliminary test results indicate that this concept with using elastomeric bearings can be a potential solution for a durable chain and should be analyzed further for fatigue conditions and under water operations.
Dynamic Modeling and Analysis of a Mobile Flexible Robot Arm
Authors: Chen Wei , Wei Lipu , Yang Xiuping , Guo Jinjin , Zhang Xizheng , Zhang Xuping
Published: November 2018

Considerable research attentions have recently been paid toward a mobile manipulator (a robot arm standing on a mobile platform) due to its extended workspace beyond the manipulator reach. Mobile manipulators have a wide range of potential applications where it is desirable to achieve higher degree of flexibility in transport and handling task. However, a vast number of research publications only focus on trajectory planning. This preliminary research work presents dynamic modeling and analysis of a mobile flexible robot arm with aims to provide insights for the design and control of such mobile robot manipulators. In this work, the dynamic model is developed using a computationally efficient method: Discrete Time Transfer Matrix Method (DT-TMM). The concepts and principle of DT-TMM are briefly overviewed, and then are applied to a mobile flexible robot arm for dynamic modeling with the detailed procedure. Numerical simulations and dynamic analyses are performed to illustrate the effectiveness of the proposed dynamic modeling method, and to provide the clues for our ongoing research work in the design and control of mobile robot manipulators.
A Design for Additive Manufacturing Ontology to Support Manufacturability Analysis
Authors: Kim Samyeon , Rosen David W. , Witherell Paul , Ko Hyunwoong
Published: November 2018

Design for additive manufacturing (DFAM) provides design freedom for creating complex geometries and guides designers to ensure manufacturability of parts fabricated using additive manufacturing (AM) processes. However, there is a lack of formalized DFAM knowledge that provides information on how to design parts and how to plan AM processes for achieving target goals, e.g., reducing build-time. Therefore, this study presents a DFAM ontology using the web ontology language (OWL) to formalize DFAM knowledge and support queries for retrieving that knowledge. The DFAM ontology has three high level classes to represent design rules specifically: feature, parameter, and AM capability. Furthermore, the manufacturing feature concept is defined to link part design to AM process parameters. Since manufacturing features contain information on feature constraints of AM processes, the DFAM ontology supports manufacturability analysis of design features by reasoning with Semantic Query-enhanced Web Rule Language (SQWRL). The SQWRL rules in this study also help retrieve design recommendations for improving manufacturability. A case study is performed to illustrate usefulness of the DFAM ontology and SQWRL rule application. This study contributes to developing a knowledge base that can be reusable and upgradable and to analyzing manufacturing analysis to provide feedback about part designs to designers.
Experimental Performance Verification of a Synchronization Based State Observer Using Only Collision Time Information
Authors: Preiswerk Pascal V. , Leine Remco I.
Published: November 2018

A state observer that only uses the collision time information has recently been developed for linear time-invariant multibody systems with unilateral constraints. The observer is based on synchronization and makes use of switched geometric unilateral constraints, which generate a unidirectional coupling in a master-slave setup. In presence of uncertainties, such as model inaccuracies or disturbances, an exact reconstruction of the observed state is not possible. As a first step in assessing the robustness of the proposed observer, we present an experimental verification of the observer’s performance. Furthermore, we account for dry friction in the observer design.
Steady-State Operability in Design for Dynamic Management in Realization of Networked Engineering Systems
Authors: Milisavljevic Syed Jelena , Commuri Sesh , Allen Janet K. , Mistree Farrokh
Published: November 2018

Digitization of networked engineered systems is a technology that is increasingly being adopted to respond to changes in the market. Hence, the need for design methods to design a system adaptable to dynamic changes in the market. It is evident through a critical review of literature that current approaches for designing of networked engineering systems are neither agile nor rapidly configurable, and, at design time, usually do not have flexibility in selection and determination of the values of design parameters to lower the overall cost during the execution of networked engineering systems and simultaneously ensure that the product quality is acceptable. Accordingly, in this paper, a method, Design for Dynamic Management, for the realization of networked engineering systems is proposed. The key features of this method, in the context of Design for Dynamic Management, are adaptability and operability in the design of systems. The efficacy of the method is illustrated on a 2-D panel stamping process. Our focus is on the method rather than the results per se.
Supplier Clustering Based on Unstructured Manufacturing Capability Data
Authors: Sabbagh Ramin , Ameri Farhad
Published: November 2018

The descriptions of capabilities of manufacturing companies can be found in multiple locations including company websites, legacy system databases, and ad hoc documents and spreadsheets. The capability descriptions are often represented using natural language. To unlock the value of unstructured capability information and learn from it, there is a need for developing advanced quantitative methods supported by machine learning and natural language processing techniques. This research proposes a multi-step unsupervised learning methodology using K-means clustering and topic modeling techniques in order to build clusters of suppliers based on their capabilities, extract and organize the manufacturing capability terminology, and discover nontrivial patterns in manufacturing capability corpora. The capability data is extracted either directly from the website of manufacturing firms or from their profiles in e-sourcing portals and directories. Feature extraction and dimensionality reduction process in this work in supported by Ngram extraction and Latent Semantic Analysis (LSA) methods. The proposed clustering method is validated experimentally based a dataset composed of 150 capability descriptions collected from web-based sourcing directories such as the Thomas Net directory for manufacturing companies. The results of the experiment show that the proposed method creates supplier cluster with high accuracy.
Establishing a Protocol to Observe Leadership Behaviors Within Engineering Design Teams
Authors: Chickarello Doug , Righter James , Patel Apurva , Summers Joshua D.
Published: November 2018

The purpose of this study is to establish a protocol capable of identifying functional leadership behaviors in engineering design teams. The protocol is developed from a literature review that includes general leadership theory and research performed on collaborative design teams. Three different raters applied the leadership protocol to a video recording of a graduate student team performing a function structure modeling activity. The results of the study demonstrate that the protocol has a high amount of intra-rater agreement and an acceptable level of interrater reliability. Additionally, the pilot study revealed that clarification and refinement of the protocol with respect to leader/follower behaviors can improve rater agreement. Finally, changes to the protocol are proposed to map leadership behaviors to the design space the team is working in and the design activities that the team is performing.
A Hybrid Computational and Analytical Model of Inline Drip Emitters
Authors: Narain Jaya , Winter Amos G.
Published: November 2018

This paper details a hybrid computational and analytical model to predict the performance of inline pressure-compensating (PC) drip irrigation emitters. The term inline refers to flow control devices mounted within the irrigation tubing. Pressure-compensating emitters deliver a relatively constant flow rate over a range applied pressure to accurately meter water to crops. Flow rate is controlled within the emitter by directing the water through a tortuous path (which imposes a fixed resistance), and then through a variable resistor composed of a flexible membrane that deflects under changes in pressure, restricting the flow path. An experimentally validated computational fluid dynamics (CFD) model was used to predict flow behavior through tortuous paths, and a pressure resistance parameter was derived to represent the pressure drop with a single variable. The bending and shearing mechanics of the membrane were modeled analytically and refined for accuracy by deriving a correction factor using finite element analysis. A least-squares matrix formulation that calculates the force applied by a line load of any shape, along which there is a prescribed deflection applied on a rectangular membrane, was derived and was found to be accurate to within one percent. The applicability of the assumption of locally fully developed flow through the pressure compensating chamber in a drip emitter was analyzed.

The combined hybrid computational-analytical model reduces the computational time of modeling drip emitter performance from days to less than 30 minutes, dramatically lowering the time required to iterate and select optimal designs. The model was validated using three commercially available drip emitters, rated at 1.1, 2, and 3.8 L/hr. For each, the model predicted the flow rate with an error of twenty percent or less, as compared to the emitter performance published by the manufacturer.
Evaluating the Project Activity Differences in Capstone Design Students via Journals
Authors: Born Werner , Schmidt Linda
Published: November 2018

Teams are employed in capstone mechanical design courses, as well as in other undergraduate courses. This puts students in a setting that they will encounter as professionals, which is beneficial to their development. For instructors, however, teams make it difficult to evaluate each individual’s understanding of the design process. While specialization is not as expected in undergraduate work, the level of variation between members of a team is not fully known. In this study design journals were kept by students during their capstone projects and entries were categorized using a coding scheme. This data revealed what a typical student recorded as activity during a capstone design project. Additionally the amount of variation within a team and among students as a whole was examined.
Simulation of Product Performance Based on Real Product-Usage Information: First Results of Practical Application to Domestic Refrigerators
Authors: van der Vegte Wilhelm Frederik , Kurt Fatih , Şengöz Oğuz Kerem
Published: November 2018

Today’s connected products increasingly allow us to collect and analyze information on how they are actually used. An engineering activity where usage data can prove particularly useful, and be converted to actionable engineering knowledge, is simulation: user behavior is often hard to model, and collected data representing real user interactions as simulation input can increase realism of simulations. This is especially useful for (i) investigating use-related phenomena that influence the product’s performance and (ii) evaluating design variations on how they succeed in coping with real users and their behaviors. In this paper we explored time-stamped usage data from connected refrigerators, investigating the influence of door openings on energy consumption and evaluating control-related design variations envisaged to mitigate negative effects of door openings. We used a fast-executing simulation setup that allowed us to simulate much faster than real time and investigate usage over a longer time. According to our first outcomes, door openings do not affect energy consumption as much as some literature suggests. Through what-if studies we could evaluate three design variations and nevertheless point out that particular solution elements resulted in better ways of dealing with door openings in terms of energy consumption.
Robustness of Nonlinear Electromagnetic Vibration Energy Harvester Subjected to Random Excitation
Authors: Drezet Cyril , Kacem Najib , Bouhaddi Noureddine
Published: November 2018

Vibration Energy Harvesters (VEHs) are devices used to collect mechanical energy from the surrounding environment to supply low power electronic systems such as Wireless Sensor Nodes. In this paper, we introduce an electromagnetic VEH model and a semi-analytical method called Moment Equation Copula Closure (MECC) that is compared to Monte Carlo simulations. Those methods are then used to derive the maximum power that can be extracted from random vibration before analyzing the effect of cubic stiffness nonlinearity on the VEH robustness against the variation of the excitation spectrum. Unlike bistable nonlinearity, it is shown that Duffing nonlinearity can be used to enhance the VEH power density and robustness with a limited effect on the harvested power.
Performance Oriented Design of Semiregular Anisotropic Porous Structures
Authors: Xu Chao , Pan Lili , Li Ming , Gao Shuming
Published: November 2018

Porous materials / structures have wide applications in industry, since the sizes, shapes and positions of their pores can be adjusted on various demands. However, the precise control and performance oriented design of porous structures are still urgent and challenging, especially when the manufacturing technology is well developed due to 3D printing. In this study, the control and design of anisotropic porous structures are studied with more degrees of freedom than isotropic structures, and can achieve more complex mechanical goals. The proposed approach introduces Super Formula to represent the structural cells, maps the design problem to an optimal problem using PGD, and solves the optimal problem using MMA to obtain the structure with desired performance. The proposed approach is also tested on the performance of the expansion of design space, the capture of the physical orientation and so on.
Instrumented Steering Wheel: Accurate Experimental Characterisation of the Forces Exerted by the Driver Hands for Future Advanced Driver Assistance Systems
Authors: Comolli Francesco , Ballo Federico M. , Gobbi Massimiliano , Mastinu Gianpiero
Published: November 2018

The interaction between driver and vehicle is analyzed in the paper. The driver acts on the steering wheel to modify the trajectory and to control the vehicle during panic situations. The knowledge of the forces exerted by the driver at the steering wheel is useful for a better understanding of the driver steering action. The final aim is to inspire the development of haptic steering wheels for better tuning of Advanced Driver Assistance Systems (ADAS).

An instrumented steering wheel has been used, which includes two six axis load cells to measure the forces and the moments exerted by the driver hands and six sensors used to measure the grip strength. Two maneuvers have been considered, a moderate speed turn and a kick plate test which simulates a panic situation with an impulsive lateral disturbance. For both of the two considered situations, some common driving behaviors have been highlighted and analyzed.

The preliminary results encourage the development of haptic instrumented steering wheels, able to improve ADAS. Actually it seems possible to infer the driver steering purpose before the steering wheel is actually rotated.
Using Multi-Stable Origami Mechanism for Peristaltic Gait Generation: A Case Study
Authors: Bhovad Priyanka , Li Suyi
Published: November 2018

This study proposes and examines a novel approach to generate peristaltic locomotion gait in a segmented origami robot. Specifically, we demonstrate how to harness elastic multi-stability embedded in a soft origami skeleton to create an earthworm-like locomotion. Origami is attractive for building soft robots because it can exhibit the essential compliance and reduce the part count. Most importantly, it can work as an actuation mechanism. Moreover, embedding multi-stability into an origami skeleton allows it to remain in any of the stable states and switch between different states via a series of jumps. In this paper, we use two serially connected bistable Kresling segments, each featuring a generalized crease pattern design and a foldable anchoring mechanism, to develop a driving module for crawling soft robot. Multi-stability analysis of this dual-segment module reveals a four-phase actuation cycle, which is then used to generate the peristaltic gait. Instead of controlling the segment deformations individually like in earthworm and other crawling robots; we only control the total length of our driving module. This approach can significantly reduce the total number of actuators needed for locomotion and simplify the control requirements. The purpose of this paper is to combine the best features of multi-stable mechanisms and origami to advance the state of art of earthworm inspired crawling soft robot. Our results demonstrate the potential of using multi-stable origami mechanisms to generate locomotion gaits without the need of complex controllers.
Decomposition-Based MDSDO for Co-Design of Large-Scale Dynamic Systems
Authors: Behtash Mohammad , Alexander-Ramos Michael J.
Published: November 2018

Conventional sequential methods are not bound to yield optimal solutions for design of physical systems and their corresponding control systems. However, by managing the interactions, combined physical and control system design (co-design) can produce superior optimal results. Existing Co-design methods are practical for moderate-scale systems; whereas, they can be impractical or impossible to use when applied to large-scale systems and consequently may limit our determination of an optimal solution. This work addresses this issue by developing a novel decomposition-based version of a co-design algorithm to optimize such large-scale dynamic systems. The new formulation implements a decomposition-based optimization strategy known as Analytical Target Cascading (ATC) to a co-design method known as Multidisciplinary Dynamic System Design Optimization (MDSDO) of a large-scale dynamic system. In addition, a new consistency measure was also established to manage time-dependent linking variables. Results substantiate the ability of the new formulation in identifying the optimal dynamic system solution.
A Study on the Structural Suitability of Tensegrity Structures to Serve As Morphing Aircraft Wings
Authors: Myszka David H. , Joo James J.
Published: November 2018

This paper presents an investigation into the structural characterization of tensegrity systems for potential use as aircraft structures, especially for morphing aircraft. Morphing aircraft provide multi-role and multi-mission capabilities by adapting their performance to different in-flight requirements. Flexible elements must be included within the structure to permit morphing capabilities compared to conventional single mission aircraft, which are designed for high rigidity and not ideal for shape morphing applications.

Tensegrity systems are structures that consist of a series of connected cables, in tension, and struts, in compression, that exist in a self-equilibrium state. Since the struts and cables are loaded axially, external loads are efficiently distributed throughout the tensegrity components resulting in a strong and stiff structure. Adjusting the pretension of the tensegrity will tailor the structural characteristics as needed without a basic configuration change. By changing the length of the cables or struts, tensegrity systems are capable of movement while maintaining their inherent strength and rigidity. This makes tensegrity systems an attractive candidate for morphing aircraft structures.

This paper quantifies the strength and rigidity of a single module of various tensegrity systems along with traditional structures to assess their ability to serve as aircraft wings. Those properties are evaluated after boundary conditions are carefully selected to avoid adding unnecessary stiffness. Lastly, a concept for a tensegrity morphing aircraft wing is presented.
NaVARo II: A New Parallel Robot With Eight Actuation Modes
Authors: Chablat Damien , Rolland Luc
Published: November 2018

This article presents a new variable actuation mechanism based on the 3-RPR parallel robot. This mechanism is an evolution of the NaVARo robot, a 3-RRR parallel robot, for which the second revolute joint of the three legs is replaced by a scissor to obtain a larger working space and avoid the use of parallelograms to operate the second revolute joint. To obtain a better spatial rigidity, the leg mechanism is constructed by placing the scissors in an orthogonal plane to the displacement. Unlike the first NaVARO robot, the kinematic model is simpler because there is only one solution to the inverse kinematic model. Surfaces of singularity can be calculated and presented in a compact form. The singularity equations are presented for a robot with a similar base and mobile platform.
Applications of Musculoskeletal Modelling and Simulation for Lower-Limb Prosthesis Design Optimization
Authors: Grabke Emerson Paul , Andrysek Jan
Published: November 2018

Lower-limb amputees can suffer from preventable pain and bone disorders attributable to suboptimal prosthesis design. Predictive modelling and simulation of human walking using conventional biomechanical gait models offer an alternative to intuition-based prosthesis design, providing insight into the biomechanics underlying pathological gait. Musculoskeletal models additionally enable understanding of prosthesis contributions to the human musculoskeletal system, and both prosthesis and individual muscle contributions to body support and propulsion during gait. Based on this review, forward dynamic simulation of amputee musculoskeletal models have been used to perform prosthesis design optimization using optimal control and reflex-based control. Musculoskeletal model complexity and assumptions inhibit fully predictive musculoskeletal modelling in its current state, hindering computational prosthesis design optimization. Future recommendations include validating musculoskeletal models and resultant optimized prosthesis designs, developing less computationally-expensive predictive musculoskeletal modelling methods, and developing more efficient patient-specific musculoskeletal model generation methods to enable personalized prosthesis optimization.
Differential Performance Signature Qualification for Additively Manufactured Parts
Authors: Michopoulos John G. , Steuben John C. , Iliopoulos Athanasios P.
Published: November 2018

Additive Manufacturing (AM) technologies and associated processes, enable successive accretion of material to a domain, and permit manufacturing of highly complex objects which would otherwise be unrealizable. However, the material micro- and meso-structures generated by AM processes can differ remarkably from those arising from conventional manufacturing (CM) methods. Often, a consequence of this fact is the sub-standard functional performance of the produced parts that can limit the use of AM in some applications. In the present work, we propose a rapid functional qualification methodology for AM-produced parts based on a concept defined as differential Performance Signature Qualification (dPSQ). The concept of Performance Signature (PerSig) is introduced both as a vector of featured quantities of interest (QoIs), and a graphical representation in the form of radar or spider graph, representing the QoIs associated with the performance of relevant parts. The PerSigs are defined for both the prequalified CM parts and the AM-produced ones. Comparison measures are defined and enable the construction of differential PerSigs (dPerSig) in a manner that captures the differential performance of the AM part vs. the prequalified CM one. The dPerSigs enable AM part qualification based on how their PerSigs are different from those of prequalified CM parts. After defining the steps of the proposed methodology, we describe its application on a part of an aircraft landing gear assembly and demonstrate its feasibility.
Feasibility Robust Optimization via Scenario Generation and Reduction
Authors: Rudnick-Cohen Eliot , Herrmann Jeffrey W. , Azarm Shapour
Published: November 2018

Feasibility robust optimization techniques solve optimization problems with uncertain parameters that appear only in their constraint functions. Solving such problems requires finding an optimal solution that is feasible for all realizations of the uncertain parameters. This paper presents a new feasibility robust optimization approach involving uncertain parameters defined on continuous domains without any known probability distributions. The proposed approach integrates a new sampling-based scenario generation scheme with a new scenario reduction approach in order to solve feasibility robust optimization problems. An analysis of the computational cost of the proposed approach was performed to provide worst case bounds on its computational cost. The new proposed approach was applied to three test problems and compared against other scenario-based robust optimization approaches. A test was conducted on one of the test problems to demonstrate that the computational cost of the proposed approach does not significantly increase as additional uncertain parameters are introduced. The results show that the proposed approach converges to a robust solution faster than conventional robust optimization approaches that discretize the uncertain parameters.
Evaluating User Intention for Uptake of Clean Technologies Using the Theory of Planned Behavior
Authors: Pakravan Mohammad H. , MacCarty Nordica
Published: November 2018

Understanding and integrating a user’s decision-making process into design and implementation strategies for clean energy technologies may lead to higher product adoption rates and ultimately increased impacts, particularly for those products that require a change in habit or behavior. To evaluate the key attributes that formulate a user’s decision-making behavior to adopt a new clean technology, this study presents the application of the Theory of Planned Behavior, a method to quantify the main psychological attributes that make up a user’s intention for health and environmental behaviors. This theory was applied to the study of biomass cookstoves. Surveys in two rural communities in Honduras and Uganda were conducted to evaluate households’ intentions regarding adoption of improved biomass cookstoves. Multiple ordered logistic regressions method presented the most statistically significant results for the collected data of the case studies. Baseline results showed users had a significant positive mindset to replace their traditional practices. In Honduras, users valued smoke reduction more than other attributes and in average the odds for a household with slightly higher attitude toward reducing smoke emissions were 2.1 times greater to use a clean technology than someone who did not value smoke reduction as much. In Uganda, less firewood consumption was the most important attribute and on average the odds for households were 1.9 times more to adopt a clean technology to save fuel than someone who did not value fuelwood saving as much. After two months of using a cookstove, in Honduras, households’ perception of the feasibility of replacing traditional stoves, or perceived behavioral control, slightly decreased suggesting that as users became more familiar with the clean technology they perceived less hindrances to change their traditional habits. Information such as this could be utilized for design of the technologies that require user behavior changes to be effective.
Managing Conflicting Water Resource Goals and Uncertainties in a Dam-Network by Exploring the Solution Space
Authors: Guo Lin , Zamanisabzi Hamed , Neeson Thomas M. , Allen Janet K. , Mistree Farrokh
Published: November 2018

In a multi-reservoir system, ensuring adequate water availability across reservoirs while managing conflicting goals under uncertainties are critical to making the social-ecological system sustainable. The priorities of multiple user-groups and availability of the water resource may vary with time, weather and other factors. Uncertainties such as variation in precipitation bring more complexity, which intensifies the discrepancies between water supply and water demand for each user-group. To reduce such discrepancies, we should satisfice conflicting goals, considering typical uncertainties.

We observed that models are incomplete and inaccurate, which challenge the use of the single optimal solution to be robust to uncertainties. So, we explore satisficing solutions that are relatively insensitive to uncertainties, by incorporating different design preferences, identifying sensitive segments and improving the design accordingly. This work is an example of exploring the solution space to enhance sustainability in multidisciplinary systems, when goals conflict, preferences are evolving, and uncertainties add complexity.
Damage Assessment on the Surface and Honeycomb Core of the Aluminum Sandwich Panel Subjected to Low-Velocity Impact
Authors: Sun Mengqian , Kendall Patrick , Wowk Diane , Kim Il Yong , Mechefske Christopher
Published: November 2018

Sandwich panels consisting of aluminum face-sheets and honeycomb core are widely used in transportation systems. The composite structure has a high stiffness and strength, but it is susceptible to impacts in service. An experimental investigation of surface deformation and core damage in a honeycomb sandwich panel subjected to three different low-velocity impact energies was undertaken. Surface damage evaluation using 3D laser scanning technology was conducted to assess the surface damage and a comparison was made with two typical indentation profiles which were proposed mathematically in the past. The experimental dent profile shows a good agreement with one of the two analytical dent profiles. The impacted sandwich panel was then cut transversely to study the damage inside the honeycomb core. The number of buckled or collapsed folds under the damaged top face-sheet and the depth of the core damage were utilized as two parameters to quantify the damage of the honeycomb core. It is concluded that the core damage depth and the number of folds is independent of impact energy and is constant within each dent.
An Electricity Grid As an Agent-Based Market System: Exploring the Effects of Policy on Sustainability
Authors: Hoffenson Steven , Wisniowski Marcin
Published: November 2018

Electricity generation is a major source of air pollution, contributing to nearly one-third of the total greenhouse gas emissions in the United States. As with most goods, production must keep up with the projected consumer demand, and the industry is subject to government regulations at the federal, state, and local levels. This study models the New Jersey electric grid as a market system, using agent-based modeling to represent individual consumers and power companies making utility-maximizing decisions. Each consumer agent is prescribed a unique value function that includes factors such as income, energy intensity, and environmental sensitivity, and they are able to make decisions about how much energy they use and whether they opt into a renewable energy program. Power producers are modeled to keep up with demand and minimize their cost per unit of electricity produced, and they include options to prefer either on-demand or renewable energy sources. Using this model, different scenarios are examined with respect to producer strategy and government policy. The results provide a proof-of-concept for the modeling approach, and they reveal interesting trends about how the markets are expected to react under different scenarios.
Fixated on Fixation? An Exploration of the Benefits and Deficits of Design “Fixation” in Engineering Design
Authors: Starkey Elizabeth M. , Zeng Wendy , Miller Scarlett R.
Published: November 2018

Design fixation is often thought of only as a limiting factor when a designer is generating ideas, but design fixation is defined only as ‘sometimes counter-productive’ indicating that there may be room for good fixation. In addition, design fixation is defined as a ‘blind adherence’, meaning that the designer does not know that they are limiting their idea set. Prior work in fixation has focused on how introducing designers to bad examples can cause a negative adherence to a limited set of ideas, while work in design by analogy has focused on how introducing a designer to the right idea can positively impact the creative output of idea generation. In addition, product dissection has been investigated as a way to inspire creative design with positive results. While researchers have investigated good examples for their positive impact on the creativity of generated ideas, little work has investigated how these good examples are having a positive impact. Therefore, this study aims to understand how exposing designers to different types of products through a product dissection activity impacts how designers are reusing parts in their ideation. In addition, this study investigates if these reuses are unconscious through the use of eye tracking equipment. The results show that reuse of parts is positively related to an individual’s creativity during idea generation. In addition, they show that there is no relationship between eye fixations and design fixation, indicating that reuse might not be unconscious. Overall, the results shed a positive light on reuse and design fixation.
Review of Natural Fiber Reinforced Elastomer Composites
Authors: Kooshki Pantea , Kwok Tsz-Ho
Published: November 2018

This paper is a review on mechanical characteristics of natural fibers reinforced elastomers (both thermoplastics and thermosets). Increasing environmental concerns and reduction of petroleum resources attracts researchers attention to new green eco-friendly materials. To solve these environmental related issues, cellulosic fibers are used as reinforcement in composite materials. These days natural fibers are at the center of attention as a replacement for synthetic fibers like glass, carbon, and aramid fibers due to their low cost, satisfactory mechanical properties, high specific strength, renewable resources usage and biodegradability. The hydrophilic property of natural fibers decreases their compatibility with the elastomeric matrix during composite fabrication leading to the poor fiber-matrix adhesion. This causes low mechanical properties which is one of the disadvantages of green composites. Many researches have been done modifying fiber surface to enhance interfacial adhesion between filler particles and elastomeric matrix, as well as their dispersion in the matrix, which can significantly affect mechanical properties of the composites. Different chemical and physical treatments are applied to improve fiber/matrix interlocking.
A Novel Computationally Efficient Pseudo-2D Approach for Modeling Single Cell of a High-Temperature Solid Oxide Fuel Cell Using Modal Analysis
Authors: Ghorbani Babak , Vijayaraghavan Krishna
Published: November 2018

A novel pseudo-2D computationally-efficient approach is developed by modal analysis for modeling a single cell of a high-temperature solid oxide fuel cell. The model is called a pseudo-2D as it fully models the flow in the flow direction and captures the effects of diffusion in the transverse direction using modal analysis. To improve convergence, the model uses a precalculated relation between the cell temperature and current density without explicitly solving the energy equation. The model is shown to agree with results obtained by previous researches and the solution convergence is significantly quicker than 3D CFD simulations. The model will be used in the future works of this research group for stack modeling, optimization, and online control of the cell.
Dynamic Modeling of a Quadruped With a Robotic Tail Using Virtual Work Principle
Authors: Liu Yujiong , Ben-Tzvi Pinhas
Published: November 2018

For utilizing robotic tail to stabilize and maneuver a quadruped, it is important to understand the mechanism of how the tail motion influences the quadruped motion which requires obtaining an analytic dynamic model. This paper presents a systematic methodology for modeling the dynamics of a general quadruped (capable of all 6 DOF motions) with a robotic pendulum tail based on the virtual work principle. The formulation of this model is motivated by robotic tail research, it can also be used as an alternative approach to model the quadruped dynamics other than using Lagrangian and Newton-Euler based methods. Numerical simulations are also conducted to verify both the forward and the inverse model.