bluuebunny/crossref_metadata_2025 huggingface dataset:
Challenges in Designing and Manufacturing Fully Optimized Functional Gradient Material Objects
Authors: Garland Anthony , Mocko Greg , Fadel Georges
Published: January 2015

Functionally Gradient Materials (FGM) smoothly transition from one material to another within a single object, allowing engineers to customize the physical response of different regions of the object by modifying the material composition at each region. New FGM research makes design, manufacturing, and use of FGM objects a promising alternative to homogeneous objects or composites with one direction of gradation. Heterogeneous anisotropic artifacts can be manufactured with specific 3D printing processes and potentially bring significant increases in functionalities. However, many challenges exist while designing and manufacturing these objects. This paper explores these challenges and suggests needed research. In particular the ability to model FGM objects, setup and run optimization algorithms, create manufacturing process plans, and control the manufacturing process all need more research and better software tools. In addition, researchers must rigorously test optimally designed FGM objects in order to validate the FGM object properties and the FGM design process before adoption of FGM objects by industry is likely to occur.
Using Interfaces to Drive Module Definition: Investigating the Impact of a New Design Dependency Measure
Authors: Jung Sangjin , Simpson Timothy W. , Asikoglu Oyku
Published: January 2015

Structural representations for interfaces between modules and components in a product vary widely in the literature. After reviewing several structural approaches to interface definition, a new weighted design dependency measure is described. The new representation takes into account both six different types of interfaces as well as their relative strength and frequency within a product architecture. The resulting design dependency measure provides a means for designers to quantify the change resistance in a product. In this paper, we investigate the use of this new design dependency measure to drive module identification. Specifically, we compare the resulting modules obtained by optimizing Design Structure Matrices (DSMs) using standard 0-1 representations of the interfaces to those obtained using the new design dependency measure. The results indicate that the weighted design dependency measure leads to more a logical definition of modules that maximizes within module dependencies and minimizes interactions between modules.
Optimization of Tooth Root Profile of Spur Gears for Maximum Load-Carrying Capacity
Authors: Zou Ting , Shaker Mathew , Angeles Jorge , Morozov Alexei
Published: January 2015

Increasing the strength of the gear tooth is a recurrent demand from industry. The authors report a novel approach to the design of tooth-root profile of spur gears using cubic splines, with the aim of investigating the effect of tooth-root geometry on stress concentration in order to increase the gear tooth strength by optimizing the root profile. An iterative co-simulation procedure, consisting of tooth-root profile shape synthesis via nonlinear programming and finite element analysis software tools is conducted, for the purpose of forming the tooth-root geometry design with the minimum stress concentration. The proposed design was verified to be capable of reducing the stress concentration by 21% over its conventional circular-filleted counterpart. Hence, the results showcase an innovative and sound methodology for the design of the tooth-root profile to increase gear load-carrying capacity.
A Socio-Academic Approach in Providing Renewable Energy Sources: Experiences of Mechanical Engineering Department, Mapua Institute of Technology
Authors: Manuel Mark Christian E. , Honra Jaime P. , Belino Manuel C.
Published: January 2015

Mapua Institute of Technology has been constantly engaged in providing free, renewable energy to rural and under privileged communities. Guided by the mission and vision of the School of Mechanical and Manufacturing Engineering Department and of the Office of Social Orientation and Community Involvement, the school had implemented several renewable energy activities. This paper showcases 8 different projects — 6 hydropower plant projects, 1 human kinetic harvesting demonstration facility, and 1 wind turbine project. In this paper, implemented projects are presented briefly with emphasis on the different locations, local cultural settings and different experiences encountered. It will also share how students have changed from being participants to autonomous implementers of renewable energy projects for communities.
Preliminary Calibration and Validation of a Finite Element Model of THOR Mod Kit Dummy
Authors: Untaroiu Costin D. , Putnam Jacob B. , Somers Jeffrey T. , Pellettiere Joseph A.
Published: January 2015

New vehicles are currently being developed to transport crews to space by NASA and several commercial companies. During the takeoff and landing phase, vehicle occupants are typically exposed to spinal and frontal loading. To reduce the risk of injuries during these common impact scenarios, NASA has begun research to develop new safety standards for spaceflight. The THOR, an advanced multi-directional crash test dummy, was chosen by NASA to evaluate occupant spacecraft safety due to its improved biofidelity.

Recently, a series of modifications were completed by the National Highway Traffic Safety Administration (NHTSA) to improve the bio-fidelity of the THOR dummy. The updated THOR Modification Kit (THOR-K) dummy was tested at Wright-Patterson (WP) Air Base in various impact configurations, including frontal and spinal loading. A computational finite element (FE) model of the THOR was developed in LS-DYNA software and was recently updated to match the latest dummy modifications. The main goal of this study was to calibrate and validate the FE model of the THOR-K dummy for use in future spacecraft safety studies.

An optimization-based method was developed to calibrate the material properties of the pelvic flesh model under quasi-static and dynamic loading conditions. Data in a simple compression test of pelvic flesh were used for the quasi-static calibration. The whole dummy kinematic and kinetic response under spinal loading conditions was used for the dynamic calibration. The performance of the calibrated dummy model was evaluated by simulating a separate dummy test with a different crash pulse along the spinal direction. In addition, a frontal dummy test was also simulated with the calibrated model. The model response was compared with test data by calculating its correlation score using the CORA rating system.

Overall, the calibrated THOR-K dummy model responded with high similarity to the physical dummy in all validation tests. Therefore, confidence is provided in the dummy model for use in predicting response in other test conditions such as those observed in the spacecraft landing.
Strategies for Topologic and Parametric Rule Application in Automated Design Synthesis Using Graph Grammars
Authors: Königseder Corinna , Shea Kristina
Published: January 2015

Computational Design Synthesis (CDS) is used to enable the computer to generate valid and even creative solutions for an engineering task. Graph grammars are a CDS approach in which engineering knowledge is formalized using graphs to represent designs and rules that describe possible graph transformations, i.e. changes of designs. For most engineering tasks two different kinds of rules are required: rules that change the topology and rules that change parameters of a design. One of the main challenges in CDS using both topologic and parametric rules is to decide a priori which type of rule to apply in which stage of the synthesis process. The research presented in this paper describes different strategies for the combination of topologic and parametric rules during automated design synthesis. A graph grammar for the design of gearboxes is investigated in which topologic rules change the structure, i.e. the number and connections of gears and shafts, whereas parametric rules change the layout and sizing, i.e. the dimensions and positions of gears and shafts, in the gearbox. For the generation of new designs, two simple multi-objective stochastic search algorithms are used and compared. Four different strategies are presented that determine in different ways which type of rule (topologic or parametric) to apply in which stage of the synthesis process. The presented strategies are compared considering the quantity of the generated designs, i.e. the number of topologically different designs, and their quality, i.e. their objective function values. Results show a significant influence of the chosen strategy only in an early stage of the synthesis process. The discussion examines the adaptability of the proposed strategies to other engineering tasks.
On the Interpretation of the Lagrange Multipliers in the Constraint Formulation of Contact Problems; or Why Are Some Multipliers Always Zero?
Authors: Schwab A. L.
Published: January 2015

One method for modeling idealized contact between two bodies in mechanical system is based on the constraint approach, where Lagrange multipiers are introduced, which serve as constraint forces. In the usage of this formulation, there exists a linear dependancy between the Lagrange multipliers. Moreover, it has been observed that some Lagrange multipliers are always identical to zero. This sort of contradicts the basic notion that Lagrange multipliers in mechanical systems act as constraint forces which, when constraints are violated, push the system back in the desired configuration. In this paper it will be shown, by theory and example, that the above-mentioned linear dependency of the Lagrange multipliers, together with specific entries in the Jacobian of the constraint equations, results in some Lagrange multipliers being identical to zero.
Design of a Novel Statically Balanced Mechanism for Laparoscope Holders With Decoupled Positioning and Orientating Manipulation
Authors: Kuo Chin-Hsing , Lai Shao-Jung
Published: January 2015

This paper presents a novel mechanism concept of laparoscope holders used for minimally invasive surgery (MIS). The mechanism is made of a parallelogram linkage and a parallel mechanism, which respectively serve as a robotic positioning arm and an orientating wrist of the holder. Due to its special geometry, the mechanism possesses several interesting kinematic properties. First, the laparoscope, which is held by the end-effector, can illustrate a remote center-of-motion (RCM) kinematics at the surgical incision point. Second, the position of the RCM point is solely defined by the parallelogram, whereas the orientation and insertion length of the laparoscope are governed by the parallel mechanism. Such an arrangement suggests a decoupled positioning and orientating manipulation for the holder, which is clinically helpful in laparoscopic MIS. Third, the overall mechanism including the parallelogram linkage and the parallel mechanism can be perfectly statically balanced at any configuration within the workspaces by using common linear springs. In other words, no electrical actuation or mechanical locks are required for making the laparoscope rest at any position and orientation. The design procedure for static balancing is detailed in the paper, and the theoretically perfect static balance of the mechanism is verified by a numerical example and computer simulation. Furthermore, a CAD model of the holder is constructed for evaluating its workspaces and a physical prototype is built up and tested. As a result, the prototyped holder is fully statically balanced within a sufficient workspace for practical MIS environment.
Performance Characterization of Multifunctional Wings With Integrated Solar Cells for Unmanned Air Vehicles
Authors: Perez-Rosado Ariel , Griesinger Adrian G. J. , Bruck Hugh A. , Gupta Satyandra K.
Published: January 2015

Flapping wing unmanned air vehicles (UAVs) are small light weight vehicles that typically have short flight times due to the small size of the batteries that are used to power them. During longer missions, the batteries must be recharged. The lack of nearby electrical outlets severely limits the locations and types of missions that these UAVs can be flown in. To improve flight time and eliminate the need for electrical outlets, solar cells can be used to harvest energy and charge/power the UAV. Robo Raven III, a flapping wing UAV, was developed at the University of Maryland and consists of wings with integrated solar cells. This paper aims to investigate how the addition of solar cells affects the UAV. The changes in performance are quantified and compared using a load cell test as well as Digital Image Correlation (DIC). The UAV platform reported in this paper was the first flapping wing robotic bird that flew using energy harvested from on-board solar cells. Experimentally, the power from the solar cells was used to augment battery power and increase operational time.
Statistical Characterization of Nearest Neighbors to Reliably Estimate Minimum Embedding Dimension
Authors: Chelidze David
Published: January 2015

False nearest neighbors (FNN) is one of the essential methods used in estimating the minimally sufficient embedding dimension in delay coordinate embedding of deterministic time series. Its use for stochastic and noisy deterministic time series is problematic and erroneously indicates a finite embedding dimension. Various modifications to the original method have been proposed to mitigate this problem, but those are still not reliable for noisy time series. Nearest neighbor statistics are studied for uncorrelated random time series and contrasted with the deterministic statistics. A new FNN metric is constructed and its performance is evaluated for deterministic, stochastic, and random time series. The results are also contrasted with surrogate data analysis and show that the new metric is robust to noise. It also clearly identifies random time series as not having a finite embedding dimension and provides information about the deterministic part of stochastic processes. The new metric can also be used for differentiating between chaotic and random time series.
Experimental Verification of Ground-Based Response of a Spinning, Cyclic Symmetric, Rotor Assembled to a Flexible Stationary Housing via Multiple Bearings
Authors: Tai W. C. , Shen I. Y.
Published: January 2015

This paper is to present an experimental study that measures ground-based response of a spinning, cyclic, symmetric rotor-bearing-housing system. In particular, the study focuses on rotor-housing coupled modes that are significantly dominated by housing deformation. In the experiments, a ball-bearing spindle motor, carrying a disk with four evenly spaced slots (i.e., the rotor), is mounted onto a stationary housing. The housing is a square plate supported with steel spacers at four corners and fixed to the ground. Two different ways are used to excite the rotor-housing system to measure frequency response functions (FRFs). One is to use an automatic hammer tapping at the disk, and the other is to use a piezoelectric actuator attached to the housing. Vibration of the rotor and housing is measured via a laser Doppler vibrometer and a capacitance probe. The experiments consist of two parts. The first part is to obtain FRFs when the rotor is not spinning. The measured FRFs reveal two rotor-housing coupled modes dominated by the housing. Their mode shapes are characterized by one nodal line in housing and one nodal diameter in the rotor. The second part is to obtain waterfall plots when the rotor is spinning at various speeds. The waterfall plots show that the housing dominant modes split into primary branches and secondary branches as the spin speed varies. The primary branches almost do not change with respect to the spin speed. In contrast, the secondary branches evolve into forward and backward branches. Moreover, their resonance frequencies increase and decrease at four times of the spin speed. The measured results agree well with the predictions found in the authors’ previous theoretical study [1].
System of Systems Approach to Air Transportation Design Using Nested Problem Formulation and Direct Search Optimization
Authors: Marwaha Gautam , Kokkolaras Michael
Published: January 2015

Aircraft sizing, route network design, demand estimation and allocation of aircraft to routes are different facets of the air transportation optimization problem that can be viewed as individual “systems,” since they can be conducted independently. In fact, there is a large body of literature that investigates each of these as a stand-alone problem. In this regard, the air transportation design optimization problem can be viewed as an optimal system-of-systems (SoS) design problem. The resulting mixed variable programming problem cannot be solved all-in-one (AiO) because its size and complexity grow exponentially with increasing number of network nodes. In this work, we use a nested multidisciplinary formulation and the Mesh Adaptive Direct Search (MADS) optimization algorithm to solve the optimal SoS design problem. The expansion of a regional Canadian airline’s network to enable national operations is considered as an example.
Problem Formulations for Simulation-Based Design Optimization Using Statistical Surrogates and Direct Search
Authors: Talgorn Bastien , Le Digabel Sébastien , Kokkolaras Michael
Published: January 2015

Typical challenges of simulation-based design optimization include unavailable gradients and unreliable approximations thereof, expensive function evaluations, numerical noise, multiple local optima and the failure of the analysis to return a value to the optimizer. The remedy for all these issues is to use surrogate models in lieu of the computational models or simulations and derivative-free optimization algorithms. In this work, we use the R dynaTree package to build statistical surrogates of the blackboxes and the direct search method for derivative-free optimization. We present different formulations for the surrogate problem considered at each search step of the Mesh Adaptive Direct Search (MADS) algorithm using a surrogate management framework. The proposed formulations are tested on two simulation-based multidisciplinary design optimization problems. Numerical results confirm that the use of statistical surrogates in MADS improves the efficiency of the optimization algorithm.
Assessing Students’ Emotional States: An Approach to Identify Lectures That Provide an Enhanced Learning Experience
Authors: Munoz David A. , Tucker Conrad S.
Published: January 2015

The learning process is affected by various elements in the classroom. An enhanced learning experience can maximize students’ positive emotional states, and therefore, students’ learning achievements. Thus, identifying lectures that provide a superior learning experience is critical to improving students’ attention during classroom activities. In this paper, the authors propose a methodology that quantifies students’ emotional states in order to identify lectures that provide enhanced learning experiences. An attitudinal survey considering relevant emotional states in a classroom setting such as engagement, delight, interest, boredom, frustration, and confusion was used to evaluate students’ emotions and their intensities. Correlation analysis indicated that positive and negative emotions were strongly positively correlated (r > 0.6) and moderately positively correlated (r > 0.4) among them respectively. Confusion was found to be the emotional state with lowest correlation coefficients. On the other hand, engagement and boredom were strongly negatively related with a correlation coefficient of −0.74. Additionally, perceived teaching style was at least moderately correlated to each one of the students’ emotional states. Unexpectedly, perceived teaching style was not correlated to perceived difficulty of the lecture (r = −0.01). Finally, the authors demonstrated that the use of Value Path Graph (VPG) is useful to identify lectures that provide an enhanced learning experience on various dimensions.
Towards a Semantic Web Approach for Disassembly Planning
Authors: Zhu Bicheng , Roy Utpal
Published: January 2015

Disassembly, as one of the core steps in the End of Life (EOL) activities, has been a popular topic of research in both industrial and academic areas. It not only reduces product lifecycle cost, but also substantially influences environmental impact. Although different methods have been proposed for tackling different aspects of the disassembly planning problems, certain gaps still exist. For example, in the case of the disassembly sequencing, traditional methods focus mainly on the geometry and topology constraints, but omit the important technical constraints like force (gravity), connector type, etc.; it makes these methods less efficient and realistic. Also, the determination of an optimal disassembly sequence requires an extensive exchange and sharing of the disassembly related knowledge among the different stakeholders like manufacturers, product designers, maintenance staffs and material engineers. A mechanism to support such information interoperability is important in the disassembly process. In order to address those research issues, this paper proposes a Semantic Web based Disassembly Planning Framework. In the framework, the proposed “Disassembly Core Ontology” (DCO) serves as a formal, explicit information core for different users like product designer and disassembler. By exploiting the rich semantic knowledge (like gravity, connector type, etc.) that has been explicitly embedded in the proposed DCO, it has been demonstrated that the semantic web approach has potentials to address both efficiency- and interoperability-related issues in disassembly planning problems.
Knowledge Discovery of Student Sentiments in MOOCs and Their Impact on Course Performance
Authors: Tucker Conrad S. , Dickens Bryan , Divinsky Anna
Published: January 2015

The objective of this research is to mine textual data (e.g., online discussion forums) generated by students enrolled in Massive Open Online Courses (MOOCs) in order to quantify students’ sentiment, in relation to their course performance. Massive Open Online Courses (MOOCs) are free to anyone with a computing device and a means of connecting to the internet and serve as a new paradigm for distance based education. While student interactions in traditional based brick and mortar classes are readily observable by students and instructors, quantifying the sentiments expressed by students in MOOCs remains challenging. This is in part due to the quantity of textual data being generated by students enrolled in MOOCs, in addition to a lack of quantitative methodologies that discover latent, previously unknown knowledge pertaining to student interactions and sentiments in the digital world.

The authors of this work introduce a data mining driven methodology that employs natural language processing techniques and text mining algorithms to quantify students’ sentiments, based on their textual data provided during course assignment discussions. The researchers of this work aim to help educators understand the factors that may impact student performance, team interactions and overall learning outcomes in digital environments such as MOOCs.
Self-Folding Origami Using Torsion Shape Memory Alloy Wire Actuators
Authors: Koh Je-sung , Kim Sa-reum , Cho Kyu-jin
Published: January 2015

Self-folding origami requires a low-profile actuator to be embedded in a sheet of paper-like planar material. Various actuation methods have been employed to actively fold such sheets. This paper presents a torsion shape-memory alloy (SMA) wire actuator embedded in patterned origami structures that actively folds the origami by twisting the SMA wire. A simple wire is aligned with the fold line, and each end is fixed to a facet. The twisting of the wire directly rotates the facets. This method has the advantage of using an easily available wire SMA and the advantage of a flat form factor similar to that of sheet SMA. Generally, SMA wire is used in a linear manner or as a spring. The torsion SMA wire presented in this paper is trained to generate torsional force when heated. The amount of rotation depends on the length of the wire; a 200-μm-diameter SMA wire 12 mm in length can induce 540° rotation. SMA wires are arranged in pairs side by side to rotate the facets in both directions. Maximum torque of 70 mNcm is generated in this antagonistic arrangement. The torsion SMA wire actuators enable a novel design for a programmable folding sheet that is easily manufactured and exhibits fast folding and unfolding.
M3tk: A Robot Mobility and Manipulation Modeling Toolkit
Authors: Mukherjee Rudranarayan , Myint Steven , Chang Johnny , Kim Isaac , Craft Jack , Pomerantz Marc , Kim Junggon , Peterson Lee
Published: January 2015

In this brief paper, we present an overview of the M3tk software for modeling robotic systems. M3tk contains basic kinematics, inverse kinematics, dynamics and inverse dynamics capabilities for articulated multi-rigid body systems. Written in C++, the software features a core kinematics and dynamics library, a linear algebra library specialized for use with the algorithms in M3tk, and a Graphical User Interface with full 3D visualization. It contains implementations of multiple contact mechanics models and the ability to model terrain through heightfields. M3tk also features an ability to model terrains with spatially distributed properties. There is also an ability to manipulate objects using a joystick. This paper summarizes M3tk without delving into the details of the code.
Compensating Inertia Forces During Human Load Carrying Using a Motorized Second Spine
Authors: Park Joon-Hyuk , Jin Xin , Agrawal Sunil K.
Published: January 2015

This study focuses on how the inertia force of a backpack induced by human walking can be compensated by active load modulation through a Second Spine, a device that provides an alternate pathway to transfer loads from the shoulder to the pelvis. Human walking induces periodic vertical acceleration of the upper body. A backpack worn on the upper body undergoes this same acceleration. Inertia force is induced by this acceleration and the human body has to sustain this motion and provide necessary energy.

Based on this knowledge and our previous studies on a passive Second Spine, we present studies on a motorized Second Spine that can actively modulate the vertical motion of a backpack such that the inertia forces can be reduced. This is realized by real-time sensing and actuation so that the backpack is kept inertially fixed. The performance of such a device was evaluated on an instrumented test-bed using an Instron machine, showing results in good agreement with simulation. It was shown that the backpack motion can be made nearly stationary with respect to the ground by active modulation using motors and the inertia force is reduced.
Tire Longitudinal Slip-Ratio Measurement Using a Camera
Authors: Botha Theunis R. , Els P. Schalk
Published: January 2015

The longitudinal slip-ratio is one of several parameters that govern the magnitude of the longitudinal force generated by a tire and probably the most important. As such, the longitudinal slip-ratio of a tire is an essential measurement required in the construction of longitudinal tire models. In laboratory experimental tests the slip-ratio can typically be controlled by controlling the rotational speeds of two motors. However, in in-situ tests, where the slip-ratio needs to be measured, the slip-ratio is estimated from three other measurements namely the wheel speed, vehicle speed and the rolling radius of the tire. While the wheel speed is fairly inexpensive and easy to measure accurately, the accurate measurement of vehicle speed requires an expensive GPS or similar system. The measurement of the rolling radius is often performed statically and assumed constant or can be measured with an expensive laser displacement sensor. Errors in the all of these measurements are compounded when determining the slip-ratio. This paper proposes a method of measuring the longitudinal slip-ratio by performing image correlation techniques on consecutive images of the tire-road interface obtained from a single inexpensive camera. Since the method makes use of one measurement system the probability of inducing errors in the slip-ratio is reduced.
Acoustical Investigations in Virtual Environments for a Car Passing Application
Authors: Husung Stephan , Siegel Antje , Weber Christian
Published: January 2015

Product development is dominated by reducing time and costs, which is often contradictory to the required high quality of product properties. Therefore, the demand for efficient tools, which support the product development process, is rising. Virtual Reality (VR) can be used as such a tool. The interactive presentation of simulation results using (extended) VR technologies is very helpful — especially if both the simulation tools and the VR presentation are multimodal. Due to the increasing importance of acoustics and the expectation of an improving presence in VR environments the sense of perception should be extended. For this a special audio-visual VR-system and audio-visual models are necessary. For the current investigations a spatial, interactive auralisation-system is used. The main focus of the paper lies on the state dependent reproduction of the acoustical behavior using a real-time capable, network-based sound-server. The developed methods are explained in the paper by an automotive example.
Kinematic Synthesis of Quasi-Homokinetic Four-Bar Linkages Through the Burmester and Chebyshev Theories
Authors: Figliolini Giorgio , Pennestrì Ettore
Published: January 2015

The present paper deals with the formulation of specific algorithms for the kinematic synthesis of quasi-homokinetic four-bar linkages, slider-crank mechanisms included, which are based on the fundamentals of kinematics, as the centrodes, the inflection circle, the cubic of stationary curvature, Freudenstein’s theorem, the Euler-Savary equation and Chebyshev’s theory.

These algorithms are aimed to obtain in a given range of motion, a quasi-constant transmission ratio between the driving and driven links, thus producing a quasi-homokinetic behaviour. In particular, the infinitesimal Burmester theory and the Chebyshev optimality criterion are applied to propose a compact closed-form solutions, which are validated through several significant examples.
Ideation Methods: A First Study on Measured Outcomes With Personality Type
Authors: Choo Pui Kun , Lou Zhi Ning , Camburn Bradley A. , Wood Kristin L. , Koo Ben , Grey Francois
Published: January 2015

The research reported here considers an experiment and subsequent data coding and analysis to extract correlations between personality type and ideation outcome from several methods. This article presents the background theory, research methodology, and empirical results associated with the experiment. The experiment is based on observations of designers developing a real product, and associated assessment tools, where the goal is to correlate the quality, quantity, and variety of design outcomes with respect to personality type. This approach lays the foundation for a tailored ideation method or a suite of ideation methods that takes advantage of the preferences and strengths of individuals. We find that there are significant correlations between type and ideation metrics and that these correlations are supported by related theory from psychology and business management.
Analysis of Design for X Methodologies for Complex Assembly Processes: A Literature Review
Authors: Aliende Urrutia Usue , Webb Philip , Summers Mark
Published: January 2015

Historically, products have been developed following the “we design it, you build it” approach. Design and production belonged to two independent entities, with no feedback from downstream activities to upstream activities. In order to avoid redesign costs caused by the lack of feedback, pioneer organisations began to apply methodologies such as ‘Design for Assembly’ or ‘Design for Manufacture’ on a daily basis.

Over the years, further research has been carried out to refine these generic methodologies adding previously unconsidered perspectives, such as quality, reliability, environmental, etc. which evolved into a concept called ‘Design-for-X’ (DfX). However, existing methodologies have largely focused on simply reducing product’s structural costs, without taking into consideration other important aspects of more complex assembly processes common in the aerospace industry.

The complex assembly process that this paper focuses on is the systems’ installation process within the aerospace business. The installation of fuel, electrical and other systems must follow strict aerospace regulations, intra-organisational design rules, safety policies and many more restrictions, which are not considered as key factors in current methodologies.

In this paper, we endeavour to provide an extensive analysis of existing DfX methodologies and support our conclusion that there is an opportunity to develop a new methodology which will ease the aerospace systems’ installation process for the shop-floor operator.
Crowdsourcing Measures of Design Quality
Authors: Wu Hao , Corney Jonathan , Grant Michael
Published: January 2015

Today there are numerous examples of collaborative online communities effectively creating innovative products (e.g., RepRap, Linux). But the potential of anonymous crowds to also engage in generative design, through the aggregation of many small contributions, is less clear. Although in recent years the “power of the crowd” has been repeatedly demonstrated in areas that range from image labelling to linguistic translation. The application of crowdsourcing in the fields of design research and creative innovation has been much slower to emerge. As a result, although there have been reports of systems and researchers using Internet crowdsourcing to carry out generative design, there are still many gaps in knowledge about the capability and limitations of the technology. For example on commercial crowdsourcing platforms, the relationship between remuneration and the final quality of designs has not been established, so it is unclear how much payment should be offered in order to ensure a particular standard of result. Key to investigating the relationship between the crowd’s remuneration and the value of their innovation is a robust method for quantifying the quality of the designs produced. This paper reports how payment for a design task (a 2D layout problem) was systematically varied and the quality of the output assessed through a separate crowdsourcing process. The work provides some interesting and valuable insight into how Crowdsourcing can be most effectively employed in design tasks.
Adaptive Surrogate-Model Fitting Using Error Monotonicity
Authors: Steuben John , Turner Cameron
Published: January 2015

Surrogate models are useful in a wide variety of engineering applications. The employment of these computationally efficient surrogates for complex physical models offers a dramatic reduction in the computational effort required to conduct analyses for the purpose of engineering design. In order to realize this advantage, it is necessary to “fit” the surrogate model to the underlying physical model. This is a considerable challenge as the physical model may consist of many design variables and performance indices, exhibit nonlinear and/or mixed-discrete behaviors, and is typically expensive to evaluate. As a result adaptive sequential sampling techniques, where previous evaluations of the physical model dictate subsequent sample locations, are widely used. In this work, we develop and demonstrate a novel adaptive sequential sampling algorithm for fitting surrogate models of any type, with a focus on large data sets. By examining the monotonicity of an error function the design space is repeatedly partitioned in order to compute a set of “key points.” The key points reduce the problem of fitting to one of precise interpolation, which can be accomplished using well-known methods. We demonstrate the use of this technique to fit several surrogate model types, including blended Hermitian polynomials and Non-Uniform Rational B-splines (NURBs), to nonlinear noisy data. We conclude with our observations as to the effectiveness of this fitting technique, its strengths and limitations, as well as a discussion of further work in this vein.
Creation of Empathic Lead Users From Non-Users via Simulated Lead User Experiences
Authors: Vaughan Meagan R. , Seepersad Carolyn C. , Crawford Richard H.
Published: January 2015

Customer Needs Analysis (CNA) is a common method used to help non-user designers to identify latent user needs. However, efforts by engineers in developed countries to conduct CNA with lead users from developing countries is complicated by differences in culture, geographical location, and language among participants. To overcome these issues, we present in this paper an alternative strategy to create Empathic Lead Users (ELU) from non-user product design engineers through the use of simulated lead user experiences.

The strategy for creating ELU includes two exercises to build empathic understanding of the needs of lead users. The problem selected for this case study was to improve lower-limb prosthetics for amputees in developing countries. The first exercise was an academic, lecture-style training session — based on videos, photos, and literature — to build understanding of the needs of amputees worldwide and in a particular developing country, Bolivia. The second exercise simulated the experiences of lead users by allowing participants to don, ambulate, and doff a mock-prosthetic limb. Each participant was interviewed before, between, and after the experiences and customer needs were interpreted from their responses. For comparison, lead users in Bolivia and typical users in the United States were similarly interviewed and customer needs interpreted from their responses.

The ELU participants were able to identify a majority of the lead user group’s needs and the traditional user group’s needs, 95% and 95% respectively. Further, by completing a CNA with the ELU group, there was a 100% increase in the number of latent needs that could be utilized in future design efforts in this study, relative to the 5 latent needs identified by the lead users themselves. As a result of this study, it appears that customer needs analysis with ELU helps to identify more latent needs, and possibly more avenues for product innovations, than interviewing lead or traditional users alone.
Build Direction for Improved Process Plan in Multi-Material Additive Manufacturing
Authors: Khoda Bashir
Published: January 2015

Current additive manufacturing processes mostly accustomed with mono-material process plan algorithm to build object layer by layer. However, building a multi-material or heterogeneous object with an additive manufacturing system is fairly new but emerging concept. Unlike mono-material object, heterogeneous object contains multiple features or inhomogeneous architecture and can be decomposed into two dimensional heterogeneous layers with islands where each island represents associated feature’s properties. The material deposition path-plan in such multi-feature/multi-contour layers requires more resources and may affect the part integrity, quality, and build time. A novel framework is presented in this paper to determine the optimum build direction for heterogeneous object by differentiating the slice based on the resources requirement. Slices are bundled based on the heterogeneity and the effect of build directions are quantified considering the feature characteristics and manufacturing attributes. The proposed methodology is illustrated by examples with 50% or more homogeneous slices along the optimum build direction. The outcome would certainly benefit the process plan for multi-material additive manufacturing techniques.
Development of a Low-Cost Underactuated and Self-Adaptive Robotic Hand
Authors: Foody James , Maxwell Karl , Hao Guangbo , Kong Xianwen
Published: January 2015

Emerging commercialised anthropomorphic hand prostheses have two main categories: expensive ones with remarkable functionality afforded by complex control systems, and inherently inexpensive ones with basic gripper-like aptitudes that do not fully fulfil the basic physical and emotional requirements of upper-limb amputees or individuals with upper limb congenital defects. This paper aims to establish a middle ground between these two commercial alternatives by realizing a low-cost and highly functional robotic hand. All five digits of the proposed robotic hand are controlled by a single DC motor. This desirable feature is afforded by the implementation of under-actuation. The under-actuation in the fingers is achieved through four-bar linkages coupling with cartwheel flexure joints, which leads to not only shape adaptation, i.e., the ability to naturally adapt to the form of the article being grasped without the aid of intricate control systems, but also low cost due to the possibility of monolithic fabrication (e.g. 3D printing) and ease of control. The under-actuation in the palm system is implemented via the use of a differential pulley mechanism embedded thereof, which furthermore results in low cost by reducing the number of actuators and simplifying the control system. A simple and easy-to-use control system based on voice commands through a smart phone was also developed. It is envisaged that the proposed design can also be applied in various engineering environments to meet adaptability/under-actuation needs.
Optimal Frequency Band Selection for the Square Envelope Spectrum in the Diagnostics of Rolling Element Bearings
Authors: Chatterton S. , Borghesani P. , Pennacchi P. , Vania A.
Published: January 2015

Diagnostics of rolling element bearings is usually performed by means of a second-order cyclostationary tool applied to the vibration signal, due to the stochastic nature of the contact between the defect and the bearing rolling elements. The most used and simple method is the Envelope Analysis that is based on the identification of bearing damage frequency components in the so-called Square Envelope Spectrum. The main critical point of this technique is the selection of a suitable frequency band for the demodulation of the vibration signal. The most used approach for the frequency band selection is based on the evaluation of the band-Kurtosis index by mean of diagrams as the frequently used Fast Kurtogram or the more recent Protrugram. Both of them may fail in the selection of the optimal frequency band when other vibration sources affect the Kurtosis index. Also critical is the constancy in the time of this optimal band. In the paper, an experimental case of a bearing damage is investigated and an alternative approach for the filter band selection, the so-called “PeaksMap”, will be proposed by the authors and compared with the ones available in the literature.
Improving Wind Turbine Drivetrain Reliability Using a Combined Experimental, Computational, and Analytical Approach
Authors: Guo Yi , Bergua Roger , van Dam Jeroen , Jove Jordi , Campbell Jon
Published: January 2015

Nontorque loads induced by the wind turbine rotor overhang weight and aerodynamic forces can greatly affect drivetrain loads and responses. If not addressed properly, these loads can result in a decrease in gearbox component life. This work uses analytical modeling, computational modeling, and experimental data to evaluate a unique drivetrain design that minimizes the effects of nontorque loads on gearbox reliability: the Pure Torque® drivetrain developed by Alstom. The drivetrain has a hub-support configuration that transmits nontorque loads directly into the tower rather than through the gearbox as in other design approaches. An analytical model of Alstom’s Pure Torque drivetrain provides insight into the relationships among turbine component weights, aerodynamic forces, and the resulting drivetrain loads. Main shaft bending loads are orders of magnitude lower than the rated torque and are hardly affected by wind conditions and turbine operations.
Optimal Actuation of Dynamically Driven Serial and Hybrid Flexure Systems
Authors: Hopkins Jonathan B. , Song Yuanping , Wang Shaoyu , Behbahani Amir H. , Josefson Ilya
Published: January 2015

In this paper, we introduce the principles necessary to guide designers in determining the optimal number and placement of actuators for driving the stage of a general serial or hybrid flexure system at any desired speed. Although the degrees of freedom (DOFs) of a flexure system are largely determined by the location and orientation of its flexure elements, the system’s stage will tend to displace in unwanted directions (i.e., parasitic errors) while attempting to traverse its intended DOFs if it is not actuated correctly. The problem of correctly placing actuators is difficult because the optimal location changes depending on the speed with which the stage is driven. Moreover the issue of correctly actuating the stage of a serial or hybrid flexure system is substantially more complicated than actuating the stage of a parallel system because serial and hybrid systems possess multiple rigid bodies, which greatly enhance the system’s dynamic complexity, and provide a host of alternative options for actuating the system with its intended DOFs. In this paper we review the principles of static and dynamic actuation space and provide the mathematics necessary to apply these spaces to serial and hybrid systems such that designers can rapidly visualize all the ways actuators can be placed to correctly drive any combination of the system’s rigid body constituents such that the system’s stage achieves the desired DOFs with minimal parasitic error at any speed.
Thin-Walled Open-Section Origami Beams for Energy Absorption
Authors: Li Yang , You Zhong
Published: January 2015

Thin-walled beams with open-section are extensively employed as energy absorption structures in transportation system, e.g., automobile bumper beams and guardrails. However, during the crushing process of these traditional open-section structures, local section flattening and lateral buckling of the webs always occur, which lead to a reduction on section-height, resulting in a significantly smaller bending resistance at the later stage of deformation and the formation of localized plastic hinges. This paper presents a novel design of high performance energy absorption beams using developable origami patterns. The origami beams overcome the problems associated with traditional open-section structures and they give nearly constant bending resistance during crushing process. Numerical analysis shows that the specific energy absorption (energy absorption per unit mass) of the origami beam is at least 20% higher in large deformation than that of the traditional thrie-beam which often used as guardrail. Our research finding demonstrates that utilising origami patterns to open-section beams can effectively alter their collapse modes, attain nearly constant bending resistance and achieve higher specific energy absorption.