bluuebunny/crossref_metadata_2025 huggingface dataset:
Networked, Real Time Translation of 3D Mesh Data to Immersive Virtual Reality Environments
Authors: Lesniak Kevin , Tucker Conrad S. , Bilen Sven , Terpenny Janis , Anumba Chimay
Published: December 2016

Immersive virtual reality systems have the potential to transform the manner in which designers create prototypes and collaborate in teams. Using technologies such as the Oculus Rift or the HTC Vive, a designer can attain a sense of “presence” and “immersion” typically not experienced by traditional CAD-based platforms. However, one of the fundamental challenges of creating a high quality immersive virtual reality experience is actually creating the immersive virtual reality environment itself. Typically, designers spend a considerable amount of time manually designing virtual models that replicate physical, real world artifacts. While there exists the ability to import standard 3D models into these immersive virtual reality environments, these models are typically generic in nature and do not represent the designer’s intent. To mitigate these challenges, the authors of this work propose the real time translation of physical objects into an immersive virtual reality environment using readily available RGB-D sensing systems and standard networking connections. The emergence of commercial, off-the shelf RGB-D sensing systems such as the Microsoft Kinect, have enabled the rapid 3D reconstruction of physical environments. The authors present a methodology that employs 3D mesh reconstruction algorithms and real time rendering techniques to capture physical objects in the real world and represent their 3D reconstruction in an immersive virtual realilty environment with which the user can then interact. A case study involving a commodity RGB-D sensor and multiple computers connected through standard TCP internet connections is presented to demonstrate the viability of the proposed methodology.
Nonlinear Forced Vibration of Curved Carbon Nanotube Resonators
Authors: Askari Hassan , Esmailzadeh Ebrahim
Published: December 2016

Nonlinear forced vibration of the nonlocal curved carbon nanotubes is investigated. The governing equation of vibration of a nonlocal curved carbon nanotube is developed. The nonlinear Winkler and Pasternak type foundations are chosen for the nanotube resonator system. Furthermore, the shape of the carbon nanotube system is assumed to be of a sinusoidal curvature form and different types of the boundary conditions are postulated for the targeted system. The Euler-Bernoulli beam theory in conjunction with the Eringen theory are implemented to obtain the partial differential equation of the system. The Galerkin method is applied to obtain the nonlinear ordinary differential equations of the system. For the sake of obtaining the primary resonance of the considered system the multiple time scales method is utilized. The influences of different parameters, namely, the position of the applied force, different forms of boundary condition, amplitude of curvature, and the coefficient of the Pasternak foundation, on the frequency response of the system were fully investigated.
Design Concept Structures in Massive Group Ideation
Authors: Lim Shi Ying Candice , Camburn Bradley Adam , Moreno Diana , Huang Zack , Wood Kristin
Published: December 2016

Empirical work in design science has highlighted that the process of ideation can significantly affect design outcome. Exploring the design space with both breadth and depth increases the likelihood of achieving better design outcomes. Furthermore, iteratively attempting to solve challenging design problems in large groups over a short time period may be more effective than protracted exploration by an isolated set of individuals. There remains a substantial opportunity to explore the structure of various design concept sets. In addition, many empirical studies cap analysis at sample sizes of less than one hundred individuals. This has provided substantial, though partial, models of the ideation space. This work explores one new territory in large scale ideation. Two conditions are evaluated. In the first condition, an ideation session was run with 2400 practicing designers and engineers from one organization. In the second condition 1000 individuals ideate on the same problem in a completely distributed environment and without awareness of each other. We compare properties of solution sets produced by each of these groups and activities. Analytical tools from network modeling theory are applied as well as traditional ideation metrics such as concept binning with saturation analysis. Structural network modeling is applied to evaluate the interconnectivity of design concepts. This is a strictly quantitative, and at the same time graphically expressive, means to evaluate the diversity of a design solution set. Observations indicate that the group condition approached saturation of distinct categories more rapidly than the individual, distributed condition. The total number of solution categories developed in the group condition was also higher. Additionally, individuals generally provided concepts across a greater number of solution categories in the group condition.

The indication for design practice is that groups of just under forty individuals would provide category saturation within group ideation for a system level design, while distributed individuals may provide additional concept differentiation. This evidence can support development of more systematic ideation strategies. Furthermore, we provide an algorithmic approach for quantitative evaluation of variety in design solution sets using networking analysis techniques. These methods can be used in complex or wicked problems, and system development where the design space is vast.
Mathematical Modelling of the Rear Drive Unit of a Lightweight Vehicle for Sensitivity Analysis of Vibration
Authors: Lin Jiewei , Qiu Yi
Published: December 2016

Lightweight technology is applied in the automobile industry because mass reduction is beneficial in improving fuel efficiency and reducing CO2 emissions. Apart from the car body and the power unit (the two heaviest parts of a vehicle), the driveline also has potential for a reduction in weight. The driveline transfers power to the wheels and plays an important role in the vehicle system. Vibration is induced by the road input and by unbalanced forces transmitted through the driveline to the car body. Mass reduction in the driveline could influence the dynamic behaviour of a vehicle but it is not yet clear how mass reduction affects vibration of the driveline, the vehicle ride and NVH performance — important considerations when designing a lightweight driveline. In the prototype design stage, a mathematical model provides a more flexible and less costly method of optimising the system dynamics.

In this paper, a 14 degree-of-freedom mathematical model is developed to study the dynamics of a rear drive unit (RDU). The system consists of a rear differential gearbox, left and right constant velocity joints and driveshafts, a rear sub-frame, and bushings between the RDU and the sub-frame and between the sub-frame and the car body. Excitations from the rear wheels, rear suspensions, and input shaft were considered. The vertical acceleration at the rear sub-frame was calculated and correlated with a calibrated multi-body dynamic model of the vehicle developed in a parallel study.

Using a fractional factorial design with the vehicle travelling on a smooth road at various speeds, a sensitivity analysis was carried out with the developed mathematical model to identify the contributions of the mass properties of the RDU and the bushing parameters to the vibration at the centre of gravity (COG) of the rear sub-frame.

Results indicate that the effects of design parameters on the rear sub-frame vibration vary according to the vehicle speed. For vibration at the rear sub-frame, the most influential factors are the masses of the rear differential gearbox and the driveshaft, and the stiffness of the front right bushings between the RDU and the sub-frame. The stiffness of the front left bushing between the RDU and the sub-frame also has considerable effect on the subsystem response but only at higher speeds. Reducing the mass of the CV joint is beneficial in decreasing the vertical vibration at the COG of the rear sub-frame, while reductions in masses of the gearbox and the driveshafts tend to slightly increase the vertical vibration at the same location. However, the adverse effect brought by lightweight differential gearbox and driveshafts on vibration is relatively small that may be hardly detected by passengers. The adverse effect (if any) can be compromised by adjusting the stiffness of the front bushings between the gearbox and the sub-frame.
Approximation of Cylindrical Surfaces With Deployable Bennett Networks
Authors: Lu Shengnan , Zlatanov Dimiter , Ding Xilun
Published: December 2016

This paper presents a one-degree-of-freedom network of Bennett linkages which can be deployed to approximate a cylindrical surface. The geometry of the unit mechanism is parameterized and its position kinematics is solved. The influence of the geometric parameters on the deployed shape is examined. Further kinematic analysis isolates those Bennett geometries for which a cylindrical network can be constructed. The procedure for connecting the unit mechanisms in a deployable cylinder is described in detail and used to gain insight into, and formulate some general guidelines for, the design of linkage networks which unfold as curved surfaces. Case studies of deployable structures in the shape of circular and elliptical cylinders are presented. Modeling and simulation validate the proposed approach.
Discovering a Hierarchical Design Process Model Using Text Mining
Authors: Lan Lijun , Liu Ying , Lu Wen Feng
Published: December 2016

The increasing design documents created in the design process provide a useful source of process-oriented design information. Hence, the need for automated design information extraction using advanced text mining techniques is increasing. However, most of the existing text mining approaches have problems in mining design information in depth, which results in low efficiency in applying the discovered information to improve the design project. With the aim of extracting process-oriented design information from design documents in depth, this paper proposes a layered text mining approach that produces a hierarchical process model which captures the process behavior at the different level of details. Our approach consists of several interrelated algorithms, namely, a content-based document clustering algorithm, a hybrid named entity recognition (NER) algorithm and a frequency-based entity relationship detection method, which have been integrated into a system architecture for extracting design information from coarse-grained views to fine-grained specifications. To evaluate the performance of the proposed algorithms, experiments were conducted on an email archive that was collected from a real-life design project. The results showed an increase in the detection accuracy for the process-oriented information detection.
Automated Mobility Analysis of Wire Flexure Systems
Authors: Satheeshbabu Sreeshankar , Krishnan Girish
Published: December 2016

Mobility analysis is an important step in the conceptual design of flexure systems. It involves identifying directions with unrestricted motion (freedoms) and directions with restricted motion (constraints). This paper proposes a deterministic framework for mobility analysis of wire flexure systems by characterizing a kinetostatic vector field known as “load flow” through its geometry. The relationship between load flow and the flexure axis is used to determine if a flexure behaves as a constraint or a freedom. This knowledge is utilized to formulate a matrix-based reduction technique to determine flexure mobility in an automated fashion. Several examples with varying complexity are illustrated to validate the efficacy of this technique. This technique is particularly useful in analyzing complex hybrid interconnected flexure topologies, which may be non-intuitive or involved with traditional methods. The proposed framework combines both visual insight and analytical rigor, and will complement existing analysis and synthesis techniques.
Towards a Constraint-Based Design of Soft Mechanisms
Authors: Satheeshbabu Sreeshankar , Krishnan Girish
Published: December 2016

Soft compliant robots and mechanisms have generated great interest due to their adaptability, and inherently safe operation. However, a systematic synthesis methodology for these devices has always remained elusive owing to complexities in geometry, and nonlinearities in deformation and material properties. This paper builds the groundwork towards a constraint based design (CBD) method for a unique class of soft robotic building blocks known as fluid-filled fiber-reinforced elastomer enclosures (FREEs). First, the constraint behavior of FREEs with varying fiber angles is mapped using an automated mobility analysis framework that is based on matrix-based kinetostatic methods. Specifically, such an analysis seeks to establish the constraint behavior of FREEs as a function of not just the global geometry, but also its local anisotropic material constituents. Then, the paper demonstrates the principle of reconfigurable constraint by combining several FREEs in series in accordance to the rules of constraint-based design. Eventual extension to actuating FREEs will enable a comprehensive synthesis methodology for soft robots.
A Novel Reconfigurable Modular Gripper for In-Hand Object Manipulation and Release With Appropriate Posture
Authors: Rahman Nahian , Carbonari Luca , D’Imperio Mariapaola , Canali Carlo , Caldwell Darwin G. , Cannella Ferdinando
Published: December 2016

In-hand manipulation is a frequently demanded task which requires a significant dexterity from grippers. Operations such as object twisting, re-grasping and re-positioning with correct posture after manipulation are the major industrial challenges. Such requiring also determine design complexity of grippers. This paper proposes a new modular two DOF finger which is capable to do manipulation such as twist object about two independent axes when used in modular assembled configuration. Multiple identical fingers of such type can be used to build the gripper whose primary purposes are solving manipulation and after manipulation requirements such as regrasp and release object with appropriate posture. The fingers are implemented in the gripper by means of a properly conceived mechanism to ensure the mobility needed for grasping. In this research, the manipulation capabilities of the gripper developed by such identical fingers is investigated by the means of simulation in a multibody simulated environment. Moreover, a prototype of one finger has been built for preliminary inspection of the modular entity which represents the constructive base of the gripper concept object of this study.
Automated Municipal Solid Waste Sorting for Recycling Using a Mobile Manipulator
Authors: Gundupalli Paulraj Sathish , Hait Subrata , Thakur Atul
Published: December 2016

Municipal solid waste (MSW), generated at an unprecedented rate due to rapid urbanization and industrialization contains useful recyclable materials like metals, plastic, wood, etc. Recycling of useful materials from MSW in the developing countries is severely constrained by limited door-to-door collection and poor means of segregation. Recovery of recyclables is usually performed by waste pickers, which is highly risky and hazardous for their health. This paper reports the development of a robotic mobile manipulation system for automated sorting of useful recyclables from MSW. The developed robot is equipped with a thermal imaging camera, proximity sensor and a 5-DOF robotic arm. This paper presents an approach for sorting based on automated identification from thermographic images. The developed algorithm extracts keypoint features from the thermographic image and feeds into clustering model to map them into a bag-of-word vectors. Finally, Support Vector Machine (SVM) classifier is used for identifying the recyclable material. We used the developed algorithm to detect three categories of recyclables namely, aluminum can, plastic bottle and tetra pack from given thermographic images. We obtained classification rate of 94.3% in the tests. In future, we plan to extend the developed approach for classifying a wider range of recyclable objects as well as to incorporate motion planning algorithms to handle cluttered environments.
On Parasitic Motion of Parallel Mechanisms
Authors: Lin Rongfu , Guo Weizhong , Gao Feng
Published: December 2016

Parasitic motion is an important kinematic phenomenon in mechanisms and a generic property of lower mobility parallel mechanisms (PMs), such as: 3-RPS PM (R denotes a rotational joint, P a prismatic joint, and S a spherical joint), Z3 head machine tool (3-PRS PM), Exechon mechanism (2-UPR-SPR, U denotes a universal joint) and so on. Parasitic motions refer to some dependent motions that accompany with other independent motions. It may introduce some undesired motion components which lead to lower manipulation accuracy/quality and more difficulties in calibration. On the other hand, it may perform a motion task by using a lower degree of freedom (DOF) PM that leads to a lower cost, lower complexity of kinematics and easier controls. We should utilize the advantages of parasitic motions and reduce/shield the disadvantages. However, the research on the parasitic motion is far from being adequate. This paper investigates the essence of the parasitic motion and gives a simple identification method. Firstly, the definitions and order of parasitic motions are discussed. Secondly, three classifications of parasitic motions are presented according to the property, amplitude and motion pattern. Then, an equation and corresponding method are detailed to identify the parasitic motion. Some examples are given to illustrate the method. Finally, the means are proposed to reduce/shield or utilize parasitic motion.
Optimization-Based Design for Specific Bistable Mechanics of Compliant Mechanisms
Authors: Zhao Jian , Gao Renjing , Liu Shutian , Huang Yu
Published: December 2016

Understanding and controlling the nonlinear bistable mechanics is crucial for the development of advanced bistable devices ranging from quantitative mass sensing to functional smart materials and structures. Currently, bistable features including the switching forces, travelling stroke, bistable index parameter ( ratio of the two switching forces) are affected complicatedly by the structure profile, size and loading cases. Due to the complex coupling effects among these bistable features, it is really difficult to design or modify one specific bistable character without affecting other bistable characters. While subjected to different loads (type and position), the phenomenon of mode switching may occur during the snap-through procedure, thus resulting in bistability uncertainty. Aiming to design specific and stable bistable characters for different application requirements, a novel optimization based bistability design method is proposed through simultaneously modifying the geometries of multi-local segments and their arrangements. With the goal of re-adjusting the bistable index parameter as well as minimizing the snapping force, the uniform cosine-shaped bistable beam is reconstructed by adding several reinforced local segments arranged symmetrically and asymmetrically along the length direction. In two numerical examples, the bistable index parameters and switching forces are properly re-designed without changing the profile and overall size of the original structure. The numerical simulation results show that the bistable index parameter can be redesigned to 1.021 and 1.2 from the original value of 0.598, thus validating the effectiveness of the optimization-based bistability design method, which exhibits great application potentials in bistability based products.
Life Cycle Decision Support Tools: The Use of Quality Management Techniques in Combating Decision Tool “Performance Decay”
Authors: Lattanzio Susan , Newnes Linda , McManus Marcelle , Dunkley Derrick
Published: December 2016

Ensuring that global infrastructure keeps pace with the demands of economic growth and human wellbeing is anticipated to result in spend of US$57 trillion (2013–30). Specific to the UK power sector, redesigning the electrical transmission network to support decarbonisation of the economy will result in an estimated spend in the region of US$50 billion (2010–20). The challenge within the infrastructure sector is in ensuring that investment productivity is maximized and the appropriate assets are built. One approach being used are decision support tools (DSTs) aimed at assisting the optimum asset choice, by considering a range of costs across the life of the asset. However, there is a gap in ensuring the sustainability of these tools: that is, ensuring that after adoption they continue to offer the same value. The research presented in this paper considers ‘performance decay’ of DSTs and proposes an approach to ensure they remain ‘fit for purpose’. Our research proposes that adopting a quality management system approach will combat performance decay, and move current DSTs from ‘static’ to ‘live’ and evolving states. Within this paper a review of literature is provided. Scenarios are used to explore possible changes in performance, and an industry exemplar used to demonstrate the plausibility of performance decay. An approach to address performance decay by embedding quality management systems techniques is then introduced.
Robustness of Adaptive, Multistable Structures Under Combined Harmonic and Stochastic Loads
Authors: Harne Ryan L. , Dai Quanqi
Published: December 2016

Multistability is a characteristic that can introduce exceptional versatility in engineered structural systems. For such adaptive structures, multiple stable equilibria empower a means for large shape change, mechanical properties tuning, and dynamic response tailoring, all potentially free from the costs and complexity associated with sustained active controls and hardware. As a result, a comprehensive understanding on the sensitivities of transitioning between the stable equilibria of multistable structures is needed to effectively leverage the valuable adaptation mechanisms. Previous characterizations provided useful insights on the dynamic sensitivities to snap-through of bi- or multistable structures under either harmonic or stochastic excitations, but the more practical combination of harmonic and stochastic loading has not received close attention. To provide a more complete understanding on the robustness of adaptive, multistable structures under complex excitations, this research explores new methods to quantify the likelihood of triggering the dynamic transitions between stable equilibria in an archetypal, magnetoelastic, bistable cantilever beam due to combined harmonic and stochastic loading. The studies capture the myriad, steady-state dynamic response regimes and susceptibilities of the bistable architecture to suddenly transition to another stable equilibria, or back again, due to various levels of additive white noise in the total excitation spectra. It is discovered that when the harmonic excitation component occurs at a frequency close to the linearized resonance the additional noise excitation rapidly disables the persistent periodic snap-through dynamics, resulting in locally stable intrawell oscillation. On the other hand, the extra noise may drastically compromise the integrity of locally stable periodic responses that occur at frequencies around one-half of the linearized resonance. By addressing the previous unknowns regarding more realistic excitation spectra, these new insights and assessment methods provide important guidance towards effective implementation of bistable constituents in adaptive structures applications.
A Review on Human Motion Prediction in Sit to Stand and Lifting Tasks
Authors: Chumacero-Polanco Erik A. , Yang James
Published: December 2016

Human-like motion prediction and simulation is an important task with many applications in fields such as occupational-biomechanics, ergonomics in industrial engineering, study of biomechanical systems, prevention of musculoskeletal disorders, computer-graphics animation of articulated figures, prosthesis and exoskeletons design as well as design and control of humanoid robots, among others.

In an effort to get biomechanical insight in many human movements, extensive work has been conducted over the last decades on human-motion prediction of tasks as: walking, running, jumping, standing from a chair, reaching and lifting. This literature review is focused on the STS motion and the LLM. STS is defined as the process of rising from a chair to standing up position without losing stability balance, it is the most ubiquitous and torque-demanding daily labor and it is closely related to other capabilities of the human body. LLM is defined as the activity of raising a load, generally a box, from a low to a higher position while stability is maintained, this task produces a high number of incidences of low-back pain and injuries in many industrial and domestic activities.

In order to predict STS and LLM, two methods have been identified: these are the OBMG method and the CBMG method.
Electrothermally Tunable Bridge Resonator
Authors: Hajjaj Amal Z. , Alcheikh Nouha , Ramini Abdallah , Al Hafiz Md Abdullah , Younis Mohammad I.
Published: December 2016

This paper demonstrates experimentally, theoretically, and numerically a wide-range tunability of an in-plane clamped-clamped microbeam, bridge, and resonator compressed by a force due to electrothermal actuation. We demonstrate that a single resonator can be operated at a wide range of frequencies. The microbeam is actuated electrothermally, by passing a DC current through it. We show that when increasing the electrothermal voltage, the compressive stress inside the microbeam increases, which leads eventually to its buckling. Before buckling, the fundamental frequency decreases until it drops to very low values, almost to zero. After buckling, the fundamental frequency increases, which is shown to be as high as twice the original resonance frequency. Analytical results based on the Galerkin discretization of the Euler Bernoulli beam theory are generated and compared to the experimental data and to simulation results of a multi-physics finite-element model. A good agreement is found among all the results.
Highly Tunable Electrothermally Actuated Arch Resonator
Authors: Hajjaj Amal Z. , Ramini Abdallah , Alcheikh Nouha , Younis Mohammad I.
Published: December 2016

This paper demonstrates experimentally, theoretically, and numerically a wide-range tunability of electrothermally actuated MEMS arch beams. The beams are made of silicon and are intentionally fabricated with some curvature as in-plane shallow arches. Analytical results based on the Galerkin discretization of the Euler Bernoulli beam theory are generated and compared to the experimental data and results of a multi-physics finite-element model. A good agreement is found among all the results. The electrothermal voltage is applied between the anchors of the clamped-clamped MEMS arch beam, generating a current that passes through the MEMS arch beam and controls its axial stress caused by thermal expansion. When the electrothermal voltage increases, the compressive stress increases inside the arch beam. This leads to increase in its curvature, thereby increases the resonance frequencies of the structure. We show here that the first resonance frequency can increase up to twice its initial value. We show also that after some electro-thermal voltage load, the third resonance frequency starts to become more sensitive to the axial thermal stress, while the first resonance frequency becomes less sensitive. These results can be used as guidelines to utilize arches as wide-range tunable resonators.
On Decentralized Optimization for a Class of Multi-Subsystem Co-Design Problems
Authors: Liu Tianchen , Azarm Shapour , Chopra Nikhil
Published: December 2016

Co-design refers to the process of integrating the optimization of the physical design as well as the controller for a system. In this paper, a new class of co-design problems with a multi-subsystem architecture is formulated and solved, which extends earlier works on models and solution approaches from single-system to multi-subsystem co-design. In this class, the design part in each subsystem has a strictly convex objective function with linear equality constraints. The control part of each subsystem belongs to a class of finite time-horizon Linear Quadratic Regulator (LQR) feedback control. A new multi-level decentralized model and method is proposed to obtain optimal or near-optimal solutions for this class of co-design problems. Details of the model and approach are demonstrated by a numerical as well as a more complex spring-mass-damper system example. Comparison of optimal results from both centralized and decentralized methods are presented and discussed.
Acoustic Beamfolding With a Miura-Ori Tessellated Transducer Array
Authors: Harne Ryan L. , Lynd Danielle T.
Published: December 2016

Vibrating structures radiate acoustic waves into the fluid media which surround them at the structure-fluid interface. Fundamentally, the interfacing structural surface topology governs the amplitude and frequency sensitivities of acoustic energy propagation away from the surface, a characteristic known as directivity. Assembling many planar acoustic transducer elements into arrays is one way to greatly enhance the far-field energy propagation directional sensitivities. Due to the spatially distributed transducers, the travelling waves combine uniquely in phase at an observation point in the far field where large energy focusing or suppressing occurs as a function of the spatial coordinates. The conventional approach to tune planar array directivity for a different purpose or new spectral sensitivity is to actively adjust each array input signal with a controlled phase delay which requires accessory hardware and computational burden. From a different standpoint, structures created from foldable, tessellated architectures, such as origami patterns, can yield enormous topological variation from the simple, kinematic motions of connected planar facets. This observation has inspired recent efforts to develop innovative, adaptable engineering systems using origami tessellations as an architectural basis for design. Considering together the topological sensitivities of planar acoustic arrays and the multifunctionality engendered by folding origami-based structures having planar facets, this research seeks to surmount the limitations of conventional acoustic arrays and explore a new idea for adaptable acoustic systems by integrating principles from acoustics and origami-inspired design. Upon the new idea, this research studies a tessellated acoustic transducer array able to drastically adapt energy guiding capabilities through simple topological folding. An array based on the Miura-ori folding pattern is examined in a new structural-acoustic model to assess the capability of folding to tune the magnitude and spatial variations of acoustic energy propagated to the far field. The acoustic directivity of the array is found to exhibit massive sensitivities based on the excitation frequency and fold angle, giving rise to large amplitude and spatial adaptation of the energy guiding to the far field point. An experimental tessellated acoustic array is fabricated and evaluated to verify the trends predicted by the model. From the measurements, it is conclusively seen that the topological change of the origami-inspired acoustic array empowers straightforward and reversible means for orders of magnitude in change in acoustic energy transmission and steering. Upon this basis, future compact, deployable, and kinematically-adaptable wave energy transmission systems may be developed for applications including field imaging, communications, and long range force projection.
Characterization of Self-Folding Origami Structures Using Magneto-Active Elastomers
Authors: Sung Elaine , Erol Anil , Frecker Mary , von Lockette Paris
Published: December 2016

Magneto-active elastomers (MAEs) are polymers with magnetic particles that are capable of aligning with an external magnetic field; this self-alignment ability is one reason why MAEs can be used as actuators for folding or bending in origami engineering. The focus of this paper is on experimental characterization and finite element modeling of an MAE folding accordion structure. The goal is to understand the relationships among the applied magnetic field, displacement of the structure during actuation, and the resultant reaction force generated. This relationship is important for applications where force generation caused by the actuation of MAE structures is required.

Data show that force increases with increasing magnetic field, and the work done by the structure can also be calculated by integrating the force. Good agreement between the finite element analysis and experimental data is shown. Future methods for improving experimentation and modeling are discussed based on the results.
Physics Based Modelling of a Magneto-Rheological Equipped Hydro-Pneumatic Semi-Active Suspension System
Authors: Heymans Gerhardus S. , Grobler Jacob F. , Els P. Schalk
Published: December 2016

The Vehicle Dynamics Group (VDG) at the University of Pretoria has developed a semi-active hydro-pneumatic suspension system for an off road vehicle. The suspension system can switch its characteristics between two discrete spring characteristics as well as two discrete damping characteristics all incorporated in a single suspension strut. This original 4-State Semi-active Suspension System (or 4S4), switches between discrete characteristics through the control a set of solenoid valves. Recently, the 4S4 was further developed with the aim of extending its damping characteristics to be continuously variable through the use of Magneto-rheological (MR) technology. The newly developed MR4S4 prototype received a re-designed flow path which channels the MR suspension fluid through two independent magnetic valves (flow orifice enclosed by coils) in parallel. The damping characteristics of each of the valves are controlled independently by the application of electric currents through damper coils. These valves are also able to block flow completely to achieve the discrete spring characteristics through switching flow to the independent accumulators.

However, in order to ensure that this new technology could be effectively applied and controlled a model of the MR4S4 needed to be developed.

This paper describes the development and validation of a physics based model which is able to capture the overall dynamics and properties of the MR4S4 suspension system. Importantly, the aim of the research was to appropriately capture the physical properties of both the gas as well as the MR fluid as it interacts with the suspension displacements and forces. This model would aid further research in the development of control strategies and provide insight through simulation studies on the systems’ influence on vehicle dynamics.
Discovering Diverse, High Quality Design Ideas From a Large Corpus
Authors: Ahmed Faez , Fuge Mark , Gorbunov Lev D.
Published: December 2016

This paper describes how to select diverse, high quality, representative ideas when the number of ideas grow beyond what a person can easily organize. When designers have a large number of ideas, it becomes prohibitively difficult for them to explore the scope of those ideas and find inspiration. We propose a computational method to recommend a diverse set of representative and high quality design ideas and demonstrate the results for design challenges on OpenIDEO — a web-based online design community. Diversity of these ideas is defined using topic modeling to identify latent concepts within the text while the quality is measured from user feedback. Multi-objective optimization then trades off quality and diversity of ideas. The results show that our approach attains a diverse set of high quality ideas and that the proposed method is applicable to multiple domains.
Utilizing Bi-Stability to Improve the Performance of Wake-Galloping Energy Harvesters in Unsteady Flow
Authors: Alhadidi Ali H. , Daqaq Mohammed F. , Abderrahmane Hamid
Published: December 2016

This paper investigates exploiting a bi-stable restoring force to enhance the transduction of wake-galloping energy harvesters in unsteady flows. To that end, a harvester consisting of a piezoelectric cantilever beam augmented with a square-sectioned bluff body at the free end is considered. Two repulsive magnets located at the tip of the beam are used to introduce the bi-stable restoring force. Unsteadiness is generated in a wind tunnel using static-grid structures located in the upstream of the bluff body. Three different mesh screens with square bars are designed with different bar and mesh widths to control the Reynolds numbers and associated unsteadiness. A series of wind tunnel tests are then used to experimentally investigate the response of the harvester with and without the tip magnets. Results demonstrate that the bi-stable restoring force can be used to improve the output power of the harvester under unsteady flow conditions.
Surface Error and Stability Chart of Beam-Type Workpiece in Milling Processes
Authors: Kiss Adam K. , Bachrathy Daniel , Stepan Gabor
Published: December 2016

In milling processes, the intermittent cutting force may lead to harmful vibrations. These vibrations are classified into two groups. One of them is the self excited vibration which comes from the loss of stability due to the regeneration effect and these vibrations lead to unacceptable chatter marks. The other one is the forced vibration which can lead to high Surface Location Error (SLE) in case of resonant spindle speeds. In this paper, the dynamics of the beam-type workpiece is considered which is modelled by means of Finite Element Analysis (FEA). Both the forced vibration and the stability properties are predicted along the tool path. The surface properties are computed on the stable regions of the stability chart which presents the chatter-free (stable) parameter domain as a function of the spindle speed and the tool path. The theoretical results are compared to the measured SLE and surface roughness.
An Automated Graph Grammar Based Tool to Automatically Generate System Bond Graphs for Dynamic Analysis
Authors: Grande Daniel , Mancini Felice , Radhakrishnan Pradeep
Published: December 2016

This paper presents a graph grammar based automated tool that can generate bond graphs of various systems for dynamic analysis. A generic graph grammar based representation scheme has been developed for different system components and bond graph elements. Using that representation, grammar rules have been developed that enable interpreting a given system and generating bond graph through an algorithmic search process. Besides, the paper also demonstrates the utility of the proposed tool in classrooms to enhance value in bond graph based system dynamics education. The underlying technique, various examples and benefits of this automated tool will be highlighted.
Comparison of Tire Footprint Measurement Techniques
Authors: Els P. S. , Stallmann M. J. , Botha T. R. , Guthrie A. G. , Wright K. R. S. , Augsburg K. , Höpping K. , Bernius V. , Sandu C. , Jimenez E.
Published: December 2016

With all wheeled vehicles, the tire contact patch is the only connection between the vehicle and the road. All the forces, except for aerodynamic forces, that are acting on the vehicle are generated in the tire contact patch. The size, shape and the pressure distribution of the contact patch are important to the performance, ride qualities and handling characteristics of a vehicle. Tire footprint studies are essential in understanding tire force generation and tire wear mechanisms. It is thus important to accurately determine the tire contact patch size and dimensions. This paper discusses various methods for measuring the static tire contact patch dimensions. A set of tests are conducted on various tires and at different inflation pressures. These tests are used to discuss the suitability of the methods depending on the type, size, load and contact surface of the tire. A list of advantages and disadvantages for each method is generated and discussed. The aim of this paper is not to study the tire footprints but to discuss the various testing methods. Insight into the different methods can help to select the suitable method for future tire contact studies.
Quantifying Model Discrepancy in Coupled Multi-Physics Systems
Authors: Friedman Samuel , Allaire Douglas
Published: December 2016

Current design strategies for multi-physics systems seek to exploit synergistic interactions among disciplines in the system. However, when dealing with a multidisciplinary system with multiple physics represented, the use of high-fidelity computational models is often prohibitive. In this situation, recourse is often made to lower fidelity models that have potentially significant uncertainty associated with them. We present here a novel approach to quantifying the discipline level uncertainty in coupled multi-physics models, so that these individual models may later be used in isolation or coupled within other systems. Our approach is based off of a Gibbs sampling strategy and the identification of a necessary detailed balance condition that constrains the possible characteristics of individual model discrepancy distributions. We demonstrate our methodology on both a linear and nonlinear example problem.
Ant Colony Optimisation Model for Vehicle Routing Problem With Simultaneous Pickup and Delivery
Authors: Scanlon Robin , Wang Qing , Wang Jie
Published: December 2016

Reverse logistics is an area that has come under increased scrutiny in recent years as legislators and companies try to increase the amount of goods that businesses reuse and recycle. The vehicle routing problem with simultaneous pickup and delivery arises when firms want to reduce handling costs by dealing with deliveries and returns in one operation. This is a complex problem for planners who aim to minimise the vehicle route length as the vehicle load rises and falls during a tour of facilities. This paper investigates the use of Ant Colony Optimisation to find solutions to this problem. An algorithm combining elements of three different studies is proposed. The algorithm finds results within 0.2% of the best known results and performs well for half of the benchmark problems, but needs further work to reach the same level on the other half. It is found that the proposed changes can have up to a 3.1% improvement in results when compared to previous methods run on this algorithm.
shapeSIFT: Evaluating InfoVis Tools for Eco-Conscious Design
Authors: Ramanujan Devarajan , Bernstein William Z. , Kulkarni Devadatta , Tew Jeffrey , Ramani Karthik
Published: December 2016

In this paper, we present the methodology and results from the evaluation of shapeSIFT: a multi-dimensional visualization tool for exploring part repositories in the context of eco-conscious design. The goals of this work are twofold, to create a categorization scheme for user evaluation methods specific to information visualization tools in eco-conscious design, and to formulate a user study for the shapeSIFT interface based on the developed categorization scheme. Our proposed scheme categorizes user evaluation methods based on two axes, (a) focus of the conducted user evaluation, and (b) development stage of the tool being evaluated. This scheme was used as the basis for conducting a guided formative expert review of the shapeSIFT interface with five domain experts in an industry setting. In this study we gathered experts’ comments, feedback, and usage behaviors, while they used the shapeSIFT interface to perform tasks reflective of real-world design practices. Results from the study show that shapeSIFT was easy-to-use and effective for part selection in the context of redesign. Motivated by these positive preliminary results, we intend to improve the shapeSIFT interface and conduct follow-up studies with a larger pool of designers.
Hybrid Design Tools in a Social Virtual Reality Using Networked Oculus Rift: A Feasibility Study in Remote Real-Time Interaction
Authors: Wendrich Robert E. , Chambers Kris-Howard , Al-Halabi Wadee , Seibel Eric J. , Grevenstuk Olaf , Ullman David , Hoffman Hunter G.
Published: December 2016

Hybrid Design Tool Environments (HDTE) allow designers and engineers to use real tangible tools and physical objects and/or artifacts to make and create real-time virtual representations and presentations on-the-fly. Manipulations of the real tangible objects (e.g., real wire mesh, clay, sketches, etc.) are translated into 2-D and/or 3-D digital CAD software and/or virtual instances. The HDTE is equipped with a Loosely Fitted Design Synthesizer (NXt-LFDS) to support this multi-user interaction and design processing. The current study explores for the first time, the feasibility of using a NXt-LFDS in a networked immersive multi-participant social virtual reality environment (VRE). Using Oculus Rift goggles and PC computers at each location linked via Skype, team members physically located in several countries had the illusion of being co-located in a single virtual world, where they used rawshaping technologies (RST) to design a woman’s purse in 3-D virtual representations. Hence, the possibility to print the purse out on the spot (i.e. anywhere within the networked loop) with a 2-D or 3D printer. Immersive affordable Virtual Reality (VR) technology (and 3-D AM) are in the process of becoming commercially available and widely used by mainstream consumers, a major development that could transform the collaborative design process. The results of the current feasibility study suggests that designing products may become considerably more individualized within collaborative multi-user settings and less inhibited during in the coming ‘Diamond Age’ [1] of VR, collaborative networks and with profound implications for the design (e.g. fashion) and engineering industry. This paper presents the proposed system architecture, a collaborative use-case scenario, and preliminary results of the interaction, coordination, cooperation, and communication with immersive VR.
Energy Symbioses in Eco-Industrial Parks: Models and Perspectives
Authors: Afshari Hamid , Farel Romain , Gourlia Jean-Paul , Peng Qingjin
Published: December 2016

Design and implementation of Eco-Industrial Parks (EIPs) is a practical and scientific solution to achieve sustainable industries. Specifically, energy exchange networks can significantly contribute to the pollution reduction by recovering and sharing wasted heat generated in industrial processes. Despite this perceived fact, the existing research seems mainly looking for one to one relation and lacks in methods for modeling and optimizing multi-synergy symbioses that is essential for EIPs. This paper reviews main concepts in designing industrial symbioses and proposes an optimization model to exchange the residual energy between individual industries in an EIP. Using mathematical programming, the model decides the best set of connections between energy suppliers and users to minimize the total cost and maximize energy symbioses. The presented models analyze perspectives to potential symbioses for individual industries and EIP managers. A detailed discussion clarifies how these perspectives can affect the optimized symbioses. The model is validated using anonymized data of a real case. The result shows that various perspectives to the model provide different energy network topographies.