bluuebunny/crossref_metadata_2025 huggingface dataset:
Thermo-Elastic Modelling of High Performance Braking Systems
Authors: Gobbi Massimiliano , Mastinu Giampiero , Previati Giorgio , Cantoni Carlo , Passoni Raffaello
Published: December 2016

The thermal and structural behaviour of carbon-carbon disc brake and pads have been studied.

A literature review was conducted to investigate recent research that has been completed in many areas related to thermo-elastic modelling of braking systems.

The friction forces generated during braking between brake pads and disc produce high thermal gradients on the rubbing surfaces. Thermo-elastic deformation results in contact concentration, leading to the non uniform distribution of temperature and pressure making the disc susceptible to hot bands and hot spots formation.

The present paper proposes a simplified modelling concept useful in the preliminary brake system design phase. Furthermore, a full finite element model related to structural/thermal analysis is presented as well. The thermo-elastic behaviour has been investigated experimentally under different braking conditions.

The models (simplified and full FE) have been validated experimentally on the basis of indoor tests results.

The accuracy of the two models is good, but the computational effort required by the full FE model can be very high.
Context-Aware Content Generation for Virtual Environments
Authors: Brock Andrew , Lim Theodore , Ritchie J. M. , Weston Nick
Published: December 2016

Large scale scene generation is a computationally intensive operation, and added complexities arise when dynamic content generation is required. We propose a system capable of generating virtual content from non-expert input. The proposed system uses a 3-dimensional variational autoencoder to interactively generate new virtual objects by interpolating between extant objects in a learned low-dimensional space, as well as by randomly sampling in that space. We present an interface that allows a user to intuitively explore the latent manifold, taking advantage of the network’s ability to perform algebra in the latent space to help infer context and generalize to previously unseen inputs.
Design and Analysis of a Two-Body Wave Energy Converter With Mechanical Motion Rectifier
Authors: Li Xiaofan , Liang Changwei , Zuo Lei
Published: December 2016

The design and dynamic analysis of a two-body wave energy converter with 50W average output power is presented in this paper. The wave energy is extracted through the relative motion between a floating buoy and a submerged body, both oscillating in the heave direction. A ball screw system is used to convert the linear relative motion into bidirectional rotation of the screw. Moreover, a mechanical motion rectifier (MMR) is used in the power take-off (PTO) design and convert the bidirectional rotation into unidirectional rotation of generator by using two one-way bearings in the gear system. The dynamic equation of this two-body wave energy converter is established by considering the engagement and disengagement of the one-way bearings in the PTO system. The simulation results in the regular and irregular waves are presented and the average output power of the proposed wave energy converter under different wave condition are estimated.
Study on Aircraft Assembly Line Balancing Problem Based on Mobile Workers
Authors: Zhang Jie , Xin Bo , Wang Pan
Published: December 2016

In order to improve the balance and load equilibrium of aircraft assembly lines, and to enhance the management of on-site resources, a Type-E balancing method was proposed based on the mobile operation of assembly personnel in the aircraft assembly line. This method was aimed to minimize the smoothness index of the overall assembly line and each assembly station, and also to minimize manpower costs. First, a model of personnel flow and an assembly line balancing model were constructed based on the characteristics of aircraft assembly lines. Next, an Accelerated Binary Particle Swarm Optimization (ABPSO) based on improved sig function was designed in order to improve the original stability and convergence of the standard binary particle swarm algorithm. Finally, the validity of the method was verified with a real fuselage assembly line and the results show the effectiveness.
Finite Element Method Based Multi Objective Topology Optimization for Enhanced Mixing With Reduced Pressure Drop
Authors: Ravichandran Madhumitha , Seshadri Arunkumar , Venkataseshan Ravichandran , Venkatesan Muniyandi
Published: December 2016

Rapid mixing in microchannels plays a significant role in chemical, biological and medical analysis fields. Microchannels are widely used for chemical and biochemical reactions because of their high surface to volume ratio. However, the rate of mixing of two or more chemical reagents is less as the flow through the micro-channel is highly laminar. Thus, two reactive fluids are predominantly parallel when they flow along the length of the channel. Generally, obstacles or surface modifications are made in the flow path which induces chaotic advection in the fluids. Considerable amount of research has been done in the past in developing different types of surface modifications to enhance the chaotic mixing. But, the intricate nature of fluid flow phenomenon makes it difficult to design the surface modification suitable to achieve the maximum rapid mixing. The present work aims at designing micromixers with the objective of obtaining rapid mixing with reduced pressure drop. A topology optimization algorithm is illustrated in the present manuscript for the design of optimal micromixer configuration. Finite element based optimization for surface modification of micromixer is developed using porosity of the channel as the control variable. In the present work, the optimisation solver works over two objectives. One is to increase the mixing in the channel and the second is to reduce the pressure drop. Numerical experiments are done to test the algorithm to obtain the optimal surface modification to achieve maximum rapid mixing between the two fluids. The results show that rapid mixing is achieved with the modified topology obtained using the code.
Approaches to Reengineering Digital Games
Authors: Ştefan Antoniu , Stănescu Ioana Andreea , Baalsrud Hauge Jannicke Madeleine
Published: December 2016

Research has highlighted Digital Games (DG)’ capacity to enhance skill and abilities through their persuasiveness and motivational appeal, which can support immersive, situated and user-centered experiences. DG development remains a challenge both in terms of costs and of the diverse range of advanced, multi-disciplinary expertise required to develop a DG. Developing DGs for such a complex domain as Mechanical Engineering (ME) to better equip engineering students to practice at the intersection of complex systems increases this challenge. An alternative to decrease costs is to capitalize on existing DGs. The paper analyzes opportunities for DG adaptation, in order to enable the reengineer of existing games to fit specific purposes and support knowledge transfer. The authors build upon current research and practices to construct an approach for adapting DG content. Two case studies are presented as a proof of concept to exemplify the different levels of the digital game reengineering process.
A Compact 2 Degree of Freedom Wrist for Robot-Actuated Surgery and Other Applications
Authors: Grames Clayton L. , Jensen Brian D. , Magleby Spencer P. , Howell Larry L.
Published: December 2016

A new, compact 2 degree-of-freedom wrist mechanism suitable for robotically controlled surgical operations is presented. Current commercially available robotically controlled instruments achieve high dexterity defined by three degrees of freedom and relatively confined swept volume at just under 1 cm in diameter. Current smaller diameter instruments result in high part count and large swept volumes (less dexterity). A mesoscale rolling contact wrist mechanism is proposed as an alternative. The crossed cylinders wrist integrates two half-cylinders whose longitudinal axes are offset by 90°. The surfaces of the half cylinders have been populated with gearing that enables the two halves to roll in two directions while preventing slip. The manufacturing of the parts is demonstrated as feasible by a the layered assembly of Carbon Nanotube (CNT) structures, which can produce parts that are difficult to replicate with traditional manufacturing methods. The resulting wrist has only 2 parts and a small swept volume.
Characterizing Competencies for Human-Centered Design
Authors: Kramer Julia , Agogino Alice M. , Roschuni Celeste
Published: December 2016

Employees and employers alike increasingly value human-centered design, as it can drive innovation across a wide range of industries. With the growing interest in understanding human-centered design processes as they apply in different professions, there is a rising need to recognize the specific competencies necessary to perform these jobs well. Though there is a body of research on how people discover, create, and use design methods, there is a lack of understanding of what core competencies are necessary for people to apply these methods. Previous interactions with target users of theDesignExchange, an interactive community-driven portal to support design researchers and practitioners, have demonstrated a desire for increased awareness of the competencies required for employability and for successful design practice. This paper reports on a portion of an expansive competency-finding project aimed at identifying the core set of competencies that human-centered design practitioners need and employers seek.

In this paper, we present our lists of cultivated mindsets, specialized disciplinary skills, contextualized tasks, and basic skills in human-centered design. These lists represent a first pass at identifying the essential and underlying competencies a practicing or aspiring human-centered designer must have in order to perform their current or future design tasks. The work we present in this paper serves as a preliminary starting point for future research interviews with design practitioners and employers, as we seek to understand human-centered design competencies.
Analysis and Modeling of Defects in Unsupported Overhanging Features in Micro-Stereolithography
Authors: Basile Vito , Modica Francesco , Fassi Irene
Published: December 2016

In the present paper, a numerical approach to model the layer-by-layer construction of cured material during the Additive Manufacturing (AM) process is proposed. The method is developed by a recursive mechanical finite element (FE) analysis and takes into account forces and pressures acting on the cured material during the process, in order to simulate the behavior and investigate the failure condition sources, which lead to defects in the final part geometry. The study is focused on the evaluation of the process capability Stereolithography (SLA), to build parts with challenging features in meso-micro scale without supports. Two test cases, a cantilever part and a bridge shape component, have been considered in order to evaluate the potentiality of the approach. Numerical models have been tuned by experimental test. The simulations are validated considering two test cases and briefly compared to the printed samples. Results show the potential of the approach adopted but also the difficulties on simulation settings.
Many-Attribute Decision Making Using Iterative Attribute Subsets
Authors: Ziegler Laura , Lewis Kemper
Published: December 2016

A unique set of cognitive and computational challenges arise in large-scale decision making, in relation to trade-off processing and design space exploration. While several multi-attribute decision making methods exist in the current design literature, many are insufficient or not fully explored for many-attribute decision problems of six or more attributes. To address this scaling in complexity, the methodology presented in this paper strategically elicits preferences over iterative attribute subsets while leveraging principles of the Hypothetical Equivalents and Inequivalents Method (HEIM). A case study demonstrates the effectiveness of the approach in the construction of a systematic representation of preferences and the convergence to a single ‘best’ alternative.
An Offsetting Framework of Triangular Models for 3D Printing
Authors: Jiang Xiaotong , Peng Qingjin , Cheng Xiaosheng , Dai Ning , Xiao Yu
Published: December 2016

An efficient and intersection-free model offsetting framework is introduced in this paper to generate shell models for 3D printing. The basic concept of the framework is to offset vertices of the input mesh to obtain an approximate discrete signed distance field for reconstructing the offsetting mesh. The framework first offsets vertices of the mesh by a given distance along their normal directly. These vertices are then adjusted or discarded according to the given offsetting distance to form an approximate discrete signed distance field using a binary space partition (BSP) tree. These reserved vertices are finally reconstructed using Poisson reconstruction algorithms to form the inner surface of the shell model. Results of the framework are intersection and non-manifold free for an arbitrary distance. It also allows different parts of a model for different offsetting distances from user interactions. Several examples are given to demonstrate that the framework is effective and robust for 3D printing.
Multi-Objective Composite Panel Optimization Using Machine Learning Classifiers and Genetic Algorithms
Authors: Zeliff Kayla , Bennette Walter , Ferguson Scott
Published: December 2016

Design spaces that consist of millions or billions of design combinations pose a challenge to current methods for identifying optimal solutions. Complex analyses can also lead to lengthy computation times that further challenge the effectiveness of an algorithm in terms of solution quality and run-time. This work explores combining the design space exploration approach of a Multi-Objective Genetic Algorithm with different instance-based, statistical, rule-based and ensemble classifiers to reduce the number of unnecessary function evaluations associated with poorly performing designs. Results indicate that introducing a classifier to identify child designs that are likely to push the Pareto frontier toward an optima reduce the number of function calculations by 75–85%, depending on the classifier implemented.
Scenario-Based Robustness Analysis of Optimized I.D.E.-Style Treadle Pump Designs
Authors: McComb Christopher , Johnson Nathan G. , Gorman Brandon T.
Published: December 2016

Poverty affects hundreds of millions of people globally. Market-based strategies can help alleviate poverty in developing countries by encouraging entrepreneurial activity and have the potential to be more effective than traditional approaches, such as development aid from countries or non-governmental organizations. Development organizations often target the agricultural sector because of the prevalence of subsistence and small-scale farming, particularly in rural regions of developing countries. Improving the reliability of irrigation techniques can help farmers expand out of primarily subsistence farming and begin to sell a portion of their crop, thus achieving the objectives of market-based poverty alleviation. Human-powered pumps are a popular tool used in irrigation because they require low capital cost and negligible operating cost. Previous work provided a model for finding Pareto-optimal IDE-style treadle pump designs. This work utilizes that model to produce a dense set of Pareto-optimal designs, and then investigates the robustness of the designs by simulating their performance in a variety of modified use scenarios. Our results show that pumps optimized for low flow rates (less than 3.0 L/s) are highly robust, particularly with respect to age-related changes in the operator’s stature or mobility. In addition, these pumps can operate with near-optimal efficiency across a variety of target flow rates and well depths. These pumps are ideal for single family use or for shared use amongst multiple families in a village. Pumps optimized for flow rates greater than 3.0 L/s are less robust with respect to changes of operator stature (experiencing decreases in flow rate of up to 60%) but may be suitable for use on farms or by service providers.
A Method to Improve Prosthesis Leg Design Based on Pressure Analysis at the Socket-Residual Limb Interface
Authors: Colombo Giorgio , Comotti Claudio , Redaelli Davide Felice , Regazzoni Daniele , Rizzi Caterina , Vitali Andrea
Published: December 2016

This paper presents a methodology and tools to improve the design of lower limb prosthesis through the measurement of pressure analysis at the interface residual limb-socket. The steps of the methodology and the design tools are presented using a case study focused on a transfemoral (amputation above knee) male amputee. The experimental setup based on F-Socket Tekscan pressure system is described as well the results of some static loading tests. Pressure data are visualized with a colour pressure map over the 3D model of the residual limb acquired using an optical low cost scanner, based on MS Kinect. Previous methodology is useful to evaluate a physical prototype; in order to improve also conceptual design, the Finite Element (FE) Analysis has been carried and results reached so far have been compared with experimental tests. Pressure distributions are comparable, even if some discrepancies have been highlighted due to sensors placements and implemented FE model. Future developments have been identified in order to improve the accuracy of the numerical simulations.
Analysis of an Energy Saving Ratchet-Based Ankle Exoskeleton
Authors: Piovesan Davide , Alladi Phanindra
Published: December 2016

This paper presents an analysis of a mechanism which aims to reduce the energy consumption during locomotion. The mechanism is based on a linear extension spring positioned in parallel with the Achilles tendon. The tension of the spring is regulated by a ratchet-pawl mechanism that engages during the flat foot phase of locomotion. The tension of the spring is used in parallel to the calf muscles to slow down the velocity of the body before the double support phase of locomotion thus avoiding the energy to be dissipated by the muscles. The release of the ratchet avoids reinjection of the energy stored in the spring back into the system. We find that this process is theoretically sound and we provide a verification of the contact stresses acting on the release mechanism.
Automated Iterative Tolerance Value Allocation and Analysis
Authors: Biswas Deepanjan , Venkiteswaran Adarsh , Hejazi Sayed Mohammad , Shah Jami J. , Davidson Joseph K.
Published: December 2016

Dimensional variation is inherent in manufacturing and it is impossible to attain exact nominal dimensions. Ideally, designer should accommodate this variation likelihood in design stage and define an allowable variation. This allowable variation is represented as tolerances and is either considered a bounded zone or a scaled allowable process standard deviation (e.g. 6 times standard deviation). The allowable tolerances are usually constrained by assemblability, functionality and manufacturing economics. Meeting these constraints simultaneously becomes a paramount task and designers usually never consider production economics when specifying tolerances. As a consequence rarely do the tolerances specified by product designer match that of the process designer. Automated tolerance value allocation can empower the product designer to include all the constraints at the design phase and reduce the overall time line between development to production. Automated tolerance allocation method described in this paper is intended for use by the designer and encompasses only 1st order tolerancing. The Critical stack detection/loop detection tool extracts the assembly level stacks that dictate assemblability. The allocation tool utilizes these stacks to distribute tolerance budget by a rule of thumb. These stacks are subjected to variation analysis to compute acceptance rates and used as feedback for iterative reallocation using a hill climbing optimization algorithm till statistical fit requirements are satisfied or allocation gets exhausted. The algorithm is tested on some case studies and presented in the paper.
Automated 1st Order Tolerancing: Schema Generation
Authors: Hejazi Sayed Mohammad , Biswas Deepanjan , Venkiteswaran Adarsh , Shah Jami J. , Davidson Joseph K.
Published: December 2016

Tolerances are specified by a designer to allow reasonable freedom to a manufacturer for imperfections and inherent variability without compromising performance. A group of tolerance classes, tolerance values and datums specified in design that control the variations in a part to be manufactured, is called a tolerance scheme. It takes knowledge and experience to create a good tolerance scheme. It is a tedious process driven by the type of parts, their features and controls needed for each one of them. In this paper, we investigate the development and implementation of 1st order automated Geometric Dimensioning and Tolerancing (GD&T) schema generation. Prior to schema generation, some assembly information such as presence of assembly features and pattern features in the given assembly CAD file is required. Mohan et al [6] proposed and implemented 3 preprocessing modules which provides required assembly information. Rao [8] developed and reported 5 experiential GD&T rulesets that could help the process of auto-tolerancing. Haghighi et al [5] proposed a procedure for automating 1st order GD&T schema generation and value allocation based on the provided assembly information and using GD&T rulesets. In this paper we present the development and implementation of 1st order GD&T schema generation. The output of this toolset is a complete GD&T schema for given assembly without tolerance values. Biswas et al [12] proposed and developed a toolset for tolerance value allocation and analysis. Once GD&T schema is generated and tolerance values are allocated, recommended GD&T is translated into STEP AP242 file format. Venkiteswaran et al [13] developed a module that reads the nominal geometry in STEP AP203 and GD&T information in CTF format and translates it to STEP AP242.

Combining all these 3 modules with pre-processing modules leads to the completion of 1st order auto-tolerancing.
Toward an Experimental Design Approach for Magnetocaloric Refrigeration Systems
Authors: Bernal Ivan , Guido Hector , Rautus Spencer , Piacenza Joseph
Published: December 2016

The magnetocaloric effect (MCE) is a magneto-thermodynamic phenomenon that heats and cools specific alloys through exposure to an alternating magnetic field. This phenomenon has the potential to create a temperature difference in a heat carrier mimicking a conventional vapor compression refrigeration cycle without harmful chemical byproducts. This research investigates the design of an experimental testing mechanism for identifying key interactions between design variables, while maximize temperature differential Key noise parameters (KNP). Fluid flow rate, magnetic field exposure time, and variations in heat exchanger configuration are explored. Understanding the significant interactions between these variables will lead to the design of a functional prototype that serves as a basis for future development in applications of the MCE for large-scale cooling systems. In this work, elemental gadolinium is used due to its high magnetic entropy change, and consequently high reversible temperature change when exposed to a magnetic field. An aqueous propylene glycol solution serves as the heat carrier based on its high heat capacity and basic pH level, reducing the possibility of degradation within the magnetocaloric material. The magnetic field is supplied by a grade N52 magnet with a magnetic field strength of approximately 0.9 Tesla. Based on this analysis, a concept stage design for experimentally maximizing the impact of the magnetocaloric effect is presented.
A MEMS Microphone Using Repulsive Force Sensors
Authors: Ozdogan Mehmet , Towfighian Shahrzad
Published: December 2016

We present a MEMS microphone that converts the mechanical motion of a diaphragm, generated by acoustic waves, to an electrical output voltage by capacitive fingers. The sensitivity of a microphone is one of the most important properties of its design. The sensitivity is proportional to the applied bias voltage. However, it is limited by the pull-in voltage, which causes the parallel plates to collapse and prevents the device from functioning properly. The presented MEMS microphone is biased by repulsive force instead of attractive force to avoid pull-in instability. A unit module of the repulsive force sensor consists of a grounded moving finger directly above a grounded fixed finger placed between two horizontally seperated voltage fixed fingers. The moving finger experiences an asymmetric electrostatic field that generates repulsive force that pushes it away from the substrate. Because of the repulsive nature of the force, the applied voltage can be increased for better sensitivity without the risk of pull-in failure. To date, the repulsive force has been used to engage a MEMS actuator such as a micro-mirror, but we now apply it for a capacitive sensor. Using the repulsive force can revolutionize capacitive sensors in many applications because they will achieve better sensitivity. Our simulations show that the repulsive force allows us to improve the sensitivity by increasing the bias voltage. The applied voltage and the back volume of a standard microphone have stiffening effects that significantly reduce its sensitivity. We find that proper design of the back volume and capacitive fingers yield promising results without pull-in instability.
Sensitivity Developments for Sensitivity-Based RBDO With Correlated Input Variable and Varying Input Standard Deviation
Authors: Cho Hyunkyoo , Choi K. K. , Lamb David
Published: December 2016

In conventional reliability-based design optimization (RBDO), the input variable is statistically independent, and its standard deviation (STD) is a fixed constant. However, the independent input variable and the constant STD may not correctly describe reliability problems because, for certain problems, the input variable is correlated, and its STD varies as the mean changes. For this kind of design problem, the input correlation should be considered, and the input STD should be changed as the design iteration proceeds and the corresponding design variable — the input mean — changes. Specifically, the varying input STD causes the input variability to fluctuate so that the probability of failure (PoF) of the design becomes a moving target. Hence, RBDO with varying input STD suffers difficulty in convergence unless accurate design sensitivity is available. In sensitivity-based RBDO, the sensitivity for the most probable point (MPP) search and the design sensitivity of probabilistic constraints are required. In this paper, it is found that the input correlation significantly affects the sensitivity for the MPP search and that the varying STD has large impact on the design sensitivity for RBDO. Therefore, sensitivities considering both the input correlation and the varying input STD have been developed for an efficient and effective optimization process. For the reliability analysis method, the enriched performance measure approach (PMA+) is used, as it is efficient and more stable during the RBDO process. To represent the input correlation, a copula is used in the sensitivity derivations. Using a mathematical example, the accuracy and efficiency of the developed sensitivities are verified. The RBDO result for the mathematical example indicates that the developed methods provide accurate sensitivities in the optimization process.
A Design for Additive Manufacturing Ontology
Authors: Dinar Mahmoud , Rosen David W.
Published: December 2016

Design for additive manufacturing (DFAM) gives designers new freedoms to create complex geometries and combine parts into one. However, it has its own limitations, and more importantly, requires a shift in thinking from traditional design for subtractive manufacturing. There is a lack of formal and structured guidelines, especially for novice designers. To formalize knowledge of DFAM, we have developed an ontology using formal OWL/RDF representations in the Protégé tool. The description logic formalism facilitates expressing domain knowledge as well as capturing information from benchmark studies. This is demonstrated in a case study with three design features: revolute joint, thread assembly (screw connection), and slider-crank. How multiple instances (build events) are stored and retrieved in the knowledge base is discussed in light of modeling requirements for the DFAM knowledge base: knowledge capture and reuse, supporting a tutoring system, integration into CAD tools. A set of competency questions are described to evaluate knowledge retrieval. Examples are given with SPARQL queries. Knowledge documentation is the main objective of the current ontology. However, description logic creates multiple opportunities for future work, including representing and reasoning about DFAM rules in a structured modular hierarchy, discovering new rules with induction, and recognizing patterns with classification, e.g., what leads to “successful” vs. “unsuccessful” fabrications.
Design and Experimental Verification of Torsion-Bending Low-Frequency Piezoelectric Energy Harvesters
Authors: Abdelmoula Hichem , Sharpes Nathan , Lee Hyeon , Abdelkefi Abdessattar , Priya Shashank
Published: December 2016

We design and experimentally validate a zigzag piezoelectric energy harvester that can generate energy at low frequencies and which can be used to operate low-power consumption electronic devices. The harvester is composed of metal and piezoelectric layers and is used to harvest energy through direct excitations. A computational model is developed using Abaqus to determine the exact mode shapes and coupled frequencies of the considered energy harvester in order to design a broadband torsion-bending mechanical system. Analysis is then performed to determine the optimal load resistance. The computational results are compared and validated with the experimental measurements. More detailed analysis is then carried out to investigate the effects of the masses on the bending and torsion natural frequencies of the harvester and generated power levels. The results show that due to the coupling between the bending and torsion modes of the zigzag structure, highest levels of the harvested power are obtained when the excitation frequency matches the coupled frequency of torsion type for three different values of the tip mass.
Evaluating an Ideation Method in a Real-Life Context: A Field Test From the Railway Sector
Authors: Petersson Anna Malou , Lundberg Jan
Published: December 2016

A great number of ideation methods are available to assist the engineer in the conceptual phase of product development. Previous research on idea generation suggests that, in order to understand how ideation can be successful in reality, the context must be taken into account. Therefore, evaluating promising ideation methods in the intended use setting should be an important complement to other research studies in the field of engineering design. In the present study, an ideation method which had previously been developed by the present authors in close collaboration with industry, a government agency, and academia was evaluated in a typical use setting. Testing the method in a use setting led to unexpected events and to new insights into the method. During the most ideation-intensive stage of the method, one of the groups in the use setting generated suggestions at a rate similar to that of the small representative group in which the development of the method had taken place, whereas the other three groups in the use setting had a lower suggestion generation rate. The findings indicated that the participants’ views on the method correlated with those of the group which had developed the method.
Using Industry Focus Groups and Literature Review to Identify Challenges in Sustainable Assessment Theory and Practice
Authors: Smullin Matteo M. , Haapala Karl R. , Mani Mahesh , Morris K. C.
Published: December 2016

The bottom up demand from consumers for more sustainable products, and the top down need to comply with government regulations motivates manufacturers to adopt tools and methods to evaluate their operations for opportunities to reduce environmental impact and improve competitiveness. Manufacturers have actively improved the sustainability of their products through the use of such tools and methods. However recently, manufacturers are struggling to maintain the necessary gains in energy and material efficiency due to the assessment inaccuracies of current ad hoc methods and their inability to identify large sustainability improvement opportunities. Overcoming this barrier requires standardized methods and tools that are implementable and which contain accurate manufacturing process-level information. To aid in developing such methods and tools, this study contrasts the perspective of industry and academic research on the topics of sustainable manufacturing metrics and measurements, and process modeling to determine the deficits that exist in enacting academic theory to practice. Furthermore, this study highlights some of the industry responses to the development of related standards for sustainability assessment.
Utilizing a Blending Function to Improve Nonlinear Frequency Response Predictions for a Pendulum System
Authors: Little Jared A. , Mazzoleni Michael J. , Mann Brian P.
Published: December 2016

This paper investigates the use of blending functions to improve nonlinear frequency response predictions for a pendulum system. The harmonic balance method is used to generate approximate analytical solutions for the amplitude-dependent natural frequency of an unforced pendulum, as well as the frequency response behavior of a forced pendulum. For both cases, separate results are obtained and compared from two different approximations for the sine function: Taylor series expansion (evaluated at the stable equilibrium position of the pendulum) and Legendre polynomial series expansion (evaluated for the pendulum’s entire range of motion). The solutions obtained from these two approximations feature a classical trade-off, with the Taylor series predictions offering superior accuracy at small to moderate amplitudes of oscillation, while the Legendre polynomial series predictions offer superior accuracy at moderate to large amplitudes of oscillation. We propose a method for blending these two results in order to obtain a hybrid analytical expression that captures the nonlinear amplitude-dependent characteristics of the pendulum system across its entire range of motion, and we validate these results with numerical studies and experimentation. We believe that this blending approach could also be applied to more complex systems whose dynamics exhibit similar nonlinear behavior to the pendulum.
A Value-Driven Design Approach to Optimize a Family of Front-Loading Washing Machines
Authors: Jung Sangjin , Simpson Timothy W. , Bloebaum Christina , Kannan Hanumanthrao , Winer Eliot , Mesmer Bryan
Published: December 2016

Existing research on the design and analysis of front-loading washing machines has primarily focused on maximizing performance of a single product based on specific disciplinary analyses (e.g., vibration, dynamics). This design approach does not necessarily guarantee low costs, high sales, and maximum profit. Moreover, in order to target a variety of different customer needs, washing machines should be thought of and designed as a product family. In this paper, we suggest a value-driven design approach for a family of front-loading washing machines to identify promising solutions based on stakeholder’s preference. To create a value function, the sales volume for front-loading washers is estimated based on sales rank data, and then the net present value (NPV) is formulated by using the estimated sales volume and a demand sensitivity curve derived from the literature and publicly available data. The result shows that we can determine product family design candidates that maximize NPV, performance, and commonality of scalable and platform (i.e., shared) variables in the washer family. We also investigate the effectiveness of reducing the complexity of the value function based on rank ordering and parametric studies of the attributes used to compute NPV.
The Development and Effects of Teaching Perspective Free-Hand Sketching in Engineering Design
Authors: Hilton Ethan , Li Wayne , Newton Sunni H. , Alemdar Meltem , Pucha Raghuram , Linsey Julie
Published: December 2016

As Computer-Aided Design software has become more advanced, the use of hand-drawn engineering drawings has greatly diminished. This reduction has led to free-hand sketching becoming less emphasized in engineering education. While many engineering curriculums formerly included courses dedicated entirely to sketching and hand drafting, these topics are no longer addressed by most current curriculums. However, it has been observed that sketching has many benefits including improved communication in the design process, idea generation exercises, and visualizing design ideas in three-dimensional space. While isometric sketching has long been the preferred method in engineering curriculums, there are benefits of teaching perspective sketching including the creation of more realistic sketches for communication and idea generation.

This paper presents the development of a perspective-based sketching curriculum and the study of how this method compares to more traditional methods of teaching sketching to students in a freshman level engineering graphics course.

The results show that the perspective-based sketching method leads to equivalent gains in spatial visualization skills and final design self-efficacy as the traditional method of teaching hand sketching. While maintaining these skills, the new method also taught students additional skills. Through surveys and interviews, the students expressed that these skills would be useful to them in their future coursework and careers.
An Origami-Inspired, SMA Actuated Lifting Structure
Authors: Wood Leo J. , Rendon Jaime , Malak Richard J. , Hartl Darren
Published: December 2016

Origami engineering is the study of the construction principles found in the art of origami and application of those principles to various engineering applications. Although origami engineering researchers have addressed the tasks of lifting a load and supporting a static load, to our knowledge no one has demonstrated a system combining these two important capabilities. In this paper, we describe an origami-inspired actuator that can fold flat, lift a load, and then support that load structurally with no electrical or mechanical input. The design is based on a bistable origami pattern similar to the classical origami waterbomb base, and is actuated by shape memory alloy (SMA) wires in torsion. We detail a framework for the generalized structure and actuation method of SMA wires as well as the construction and testing of a proof-of-concept lifter. This proof of concept structure, weighing 22 grams, is able to lift a 50g load in 8 seconds using a 2.5 Volt input, and statically support 200g even after the cessation of voltage input. We conduct a preliminary analysis into the parameters of the structure that most affect its lifting capabilities.
Assembly Line Balancing and Configuration: An Alternative Approach for Design and Planning
Authors: Rossoni Marco , Colombo Giorgio , Furini Francesco , Ascheri Andrea Egidio , Ippolito Massimo
Published: December 2016

One of the most important factors that allows the big enterprises to be competitive in the market is the capability to develop products that are tailored on the specific customer requirements with a short lead-time. This research aims to study an automated configuration tool for assembly lines. A KBE approach was used. The configuration process for an assembly line has been identified with the experts of a big manufacturing Italian company. One of the critical issue is that the domains knowledge is mostly tacit. The implementation stage was carried out with a commercial development tool. Thanks to a modular design of the KBE system a strong but flexible framework was achieved. The rules and data repositories, as well as the code of the single module, can be update easier. An industrial case study was used to validate the proposed approach: the configuration of a cylinder head assembly line was performed.
Investigation of the Effectiveness of Multi-Fidelity Surrogates on Extrapolation
Authors: Park Chanyoung , Haftka Raphael T. , Kim Nam H.
Published: December 2016

Surrogates have been used as an approximate tool to emulate simulation responses based on a handful of response samples. However, for high fidelity simulations, often only a small number samples are affordable, and this increases the risk of extrapolation using surrogates. Frequently, most of the sampling domain is not in the interpolation domain (called coverage), usually defined as the convex hull of these samples. For example, when we build a surrogate with 20 samples in six-dimensional space, the coverage is merely 2% of the sampling domain. Multi-fidelity surrogates (MFS) may mitigate this problem, because they use large number of low fidelity simulations, so that most of the domain is covered with at least some simulations.

This paper explores the extrapolation capability of MFS frameworks through examples including algebraic functions. To examine the effects of different MFS frameworks, we consider six MFS frameworks in terms of their functional forms and frameworks for fitting the forms to data. We consider three different functional forms based on different approaches: 1) a model discrepancy function, 2) model calibration, and 3) both. Bayesian MFS frameworks based on the functional forms are considered. We include also their counterparts in simple frameworks, which have the same functional form but can be built with ready-made surrogates. We examined the effect of the high fidelity sample coverage on extrapolation while the number of high fidelity samples remains the same. The root mean square errors (RMSE) of the interpolation and extrapolation domains are calculated to see their effectiveness on the overall RMSE of whole MFS. For the examples considered, we found that the presence of a regression scalar could be important to extrapolation. Bayesian framework is useful to find a good regression scalar, which simplifies the discrepancy function.
Analytical Solutions for Periodic Motions in a Twin-Well Potential Mathieu-Duffing Oscillator
Authors: O’Connor Dennis M. , Luo Albert C. J.
Published: December 2016

Analytical solutions for periodic motion in a twin-well potential Mathieu-Duffing oscillator with damping are obtained using the finite Fourier series solutions, and the stability and bifurcation analysis of such periodic motions are completed. To verify the approximate analytical solutions of periodic motions, numerical simulations of the twin-well solutions are presented for Period-1 asymmetric motions. Further, simulation of the unstable solutions is considered to demonstrate the resonant bands separating the twin-wells.
Product Body Shapes, Not Features, Provide Fast and Frugal Cues for Environmental Friendliness
Authors: Du Ping , MacDonald Erin F.
Published: December 2016

Mental associations between a product’s visual design and its unobservable characteristics aid consumer judgments. It is hypothesized these associations, or cues, allow people to decrease the mental load required to make a decision. This paper investigates the rapid-building of mental associations between visual cues and unobservable attributes. It questions if it is more effective to cue holistically, through body-shape, or by individual features. Subjects participated in an association-building task and were then surveyed for retention of positive and negative cues for environmental friendliness ratings. Results demonstrate retention of body shapes cues but not feature cues. Additionally, eye-tracking data demonstrate that people redistribute their attention to a product after the association-building task, increasing the percentage of attention in the cued visual areas-of-interest. This supports the hypothesis that cues work to distribute mental load more efficiently; subjects’ evaluations became more targeted when judging environmental friendliness.
A Sequential Sampling Algorithm for Multi-Stage Static Coverage Problems
Authors: Manjunatha Hemanth , Huang Jida , Zhang Binbin , Rai Rahul
Published: December 2016

It is critical in many system-engineering problems (such as surveillance, environmental monitoring, and cooperative task performance) to optimally allocate resources in the presence of limited resources. Static coverage problem is an important class of the resource allocation problems that focuses on covering an area of interest so that the activities in the area of interest can be detected/monitored with higher probability. In many practical settings (primarily due to financial constraints) a system designer has to allocate resources in multiple stages. In each stage, the system designer can assign a fixed number of resources (agents). In the multi-stage formulation, the agents locations for the next stage are dependent on all the agents location in the previous stages. Such multi-stage static coverage problems are non-trivial to solve. In this paper, we propose a robust and efficient sequential sampling algorithm to solve the multi-stage static coverage problem in the presence of probabilistic resource intensity allocation maps (RIAMs). The agents locations are determined by formulating this problem as an optimization problem in the successive stage . Three different objective functions are compared and discussed from the aspects of decreasing L2 difference and Sequential Minimum Energy Design (SMED). It is shown that utilizing SMED objective function leads to a better approximation of the RIAMs. Two heuristic algorithms, i.e. cuckoo search, and pattern search, are used as optimization algorithms. Numerical functions and real-life applications are provided to demonstrate the robustness and efficiency of the proposed approach.
Enumeration of Configurations and Their Kinematics for ModRED II Modular Robots
Authors: Hossain Kazi M. , Nelson Carl A. , Dasgupta Prithviraj
Published: December 2016

Modular robotics is a popular topic for robotic applications and design. The reason behind this popularity is the ability to use and re-use the same robot modules for accomplishing different tasks through reconfiguration. The robots are capable of self-reconfiguration based on the requirements of the task and environmental constraints. It is possible to have a large number of configuration combinations for the same set of modules. Therefore, it is important to identify unique configurations from among the full set of possible configurations and establish a kinematic strategy for each before reconfiguring the robots into a new shape. This becomes more difficult for robot units having more than one connection type and more degrees of freedom. For example, ModRED II modules have two types of connections and four degrees of freedom per module. In this paper, the set of configurations is enumerated, and determination of configuration isomorphism is accomplished for ModRED II modules using graph theory. Kinematic equations are then derived for unique configurations. The kinematic method is then demonstrated for certain example configurations using ModRED II modules.