bluuebunny/crossref_metadata_2025 huggingface dataset:
Modeling Large Deflections of Initially Curved Beams in Compliant Mechanisms Using Chained Beam-Constraint-Model
Authors: Chen Guimin , Ma Fulei , Hao Guangbo , Zhu Weidong
Published: November 2018

Understanding and analyzing large and nonlinear deflections is one of the major challenges of designing compliant mechanisms. Initially curved beams can offer potential advantages to designers of compliant mechanisms and provide useful alternatives to initially straight beams. However, the literature on analysis and design using such beams is rather limited. This paper presents a general and accurate method for modeling large planar deflections of initially curved beams of uniform cross-sections, which can be easily adapted to curved beams of various shapes. This method discretizes a curved beam into a few elements and models each element as a circular-arc beam using the beam constraint model (BCM). Two different discretization schemes are provided for the method, among which the equal discretization is suitable for circular-arc beams and the unequal discretization is for curved beams of other shapes. Compliant mechanisms utilizing initially curved beams of circular-arc, cosine and parabola shapes are modeled to demonstrate the effectiveness of CBCM for initially curved beams of various shapes. The method is also accurate enough to capture the relevant nonlinear load-deflection characteristics.
Design and Comprehensive Performance Analysis of IS-LEJ Hinges
Authors: Li Yanlin , Qiu Lifang , Wang Jinglin , Xie Zhongtian
Published: November 2018

The lamina emergent torsional (LET) joint is one of the most important components in lamina emergent mechanisms (LEMs), which can play a key role in its movement performance. This paper summarizes the existing hinges and compares their performance. Based on this, eight new flexure hinges are designed and the finite element analysis (FEA) models are created. Their bending properties, tension and compression resistant properties are analyzed respectively. In order to achieve the preliminary judgment of flexible hinge properties, comprehensive performance parameters q1 and q2 are proposed. The comprehensive performance of the eight hinges is compared according to the calculation results of q1 and q2. The theoretical formula of hinge with best performance is deduced and verified. Finally, the effect of length on the comprehensive performance of the eight hinges are analyzed. The result shows that the structure meets the design requirement of lifting comprehensive performance of hinges.
Investigating Modal Energy Redistributions in Mechanical Systems With Impulsive Stiffness Excitation by Using Effective Damping Measures
Authors: Pumhössel Thomas
Published: November 2018

In the present contribution, alternating energy transfers across modes of vibration, induced by impulsive stiffness excitation applied at equidistant instants of time are investigated. Therefore, effective damping measures are used, and it is shown that they clearly indicate modal energy transfers and their effect on the decay rate of transient vibrations. It is demonstrated that outstanding values of the time span between adjacent impulses exist, where a strong energy transfer to higher modes, which possess enhanced damping properties, occurs. Hence, the modal redistribution of vibration energy allows the intrinsic structural damping to be more efficient, resulting in a much faster decrease of vibrations compared to the system without impulsive excitation. It is demonstrated that the effective damping measures provide a proper method to investigate mechanical systems with impulsive stiffness excitation.
Experimental Investigation on the Dynamic Behavior of Chaotic Jumping in Inverted Flexible Pendulum Under Harmonic Excitation
Authors: Kahar Hartiny A. , Madadi Elmira , Söffker Dirk
Published: November 2018

Control of flexible systems is effected by design requirements and also manufacturing aspects. The dynamics and control of such systems are challenging, especially in the case of an inverted flexible pendulum system. The experimental study of the dynamical behavior of this kind of system showing jumping phenomenon between three equilibria is not considered in detail in literatures so far. The paper focuses on studying the effects of some parameters to the dynamics of the flexible pendulum. By varying the excitation parameters, control parameters, as well as other distinguished mechanical parameters, different phenomena are observed in experiments discussed in this contribution. In this study, a custom built inverted flexible pendulum on cart system under PID-controlled harmonic excitation is considered. Data are collected from both cart excitation signal and displacement of the pendulum, also to observe their correlation towards jumping behavior. Effects of the variation of the parameters leading to changes in chaotic jumping patterns. Multiple equilibria are observed and analyzed. It can be concluded that depending on the excitation amplitudes, frequencies, and controller parameters, the minimum of two equilibria with an unstable third equilibrium can be detected while jumping phenomena between the equilibria are observed. Questions about the stimulation of the jumping by impulses resulting from imperfect sinusoidal excitation due to control limitations are discussed.
Bow Actuator: Low Voltage Switching in Electrostatically Actuated Bistable Beams
Authors: Medina Lior , Gilat Rivka , Krylov Slava
Published: November 2018

Curved bistable beams subjected to transverse loading may exhibit latching, namely remain in their buckled state under zero force. Under such circumstances, an opposite force is required for snapping-back (release) of the beam to its initial configuration. For an electrostatically actuated beam, two electrodes located at either side of the beam may therefore be required for bidirectional actuation. In this study, a new snapping and release procedures, are considered. The approach involves the preloading of the beam using an electrostatic force in the direction opposite to the beam desired movement, followed by a sudden release of the voltage. We show, by means of a reduced order (RO) model, resulting from the Galerkin decomposition, that such an actuation paradigm can not only be used to release a beam from its latched position, but can also create a snap-through response at a significantly low voltage.
Experimental and Theoretical Study of Two-to-One Internal Resonance of MEMS Resonators
Authors: Hajjaj Amal Z. , Alfosail Feras K. , Younis Mohammad I.
Published: November 2018

In this paper, we investigate experimentally and theoretically the two-to-one (2:1) internal resonance between the first two symmetric vibrational modes of microelectromechanical (MEMS) arch resonator electrothermally tuned and electrostatically driven. Applying electrothermal voltage across the beam anchors controls its stiffness and then its resonance frequencies. Hence the ratio between the two frequencies can be tuned to a ratio of two. Then, we study the dynamic response of the arch beam during internal resonance. In the studied case, the presence of high AC bias excitation leads to the direct simultaneous excitation of the 1st and 3rd frequencies in addition to the activation of the internal resonance. A reduced order model and perturbation techniques are presented to analyze the nonlinear response of the structure. In the perturbation technique, the direct excitation of the 3rd resonance frequency is taken into consideration. Results show the presence of Hopf bifurcations, which can lead to chaotic motion at higher excitation. A good agreement among the theoretical and experimental results is shown.
Study on the Natural Vibration Characteristics of Single-Point Diamond Fly Cutting Machine Tool Based on Transfer Matrix Method for Multibody Systems
Authors: Ding Yuanyuan , Rui Xiaoting , Chen Gangli , Liu Xingbao , Zeng Xiaoyun
Published: November 2018

Natural vibration characteristics play a very important role in the evaluation of the dynamics characteristics and the machined surface of a single-point diamond fly cutting machine tool (SDFCMT). In this paper, the natural vibration characteristics are studied from aspects of theory, computation, and experiment. By adopting the transfer matrix method for multibody systems (MSTMM), the dynamics model and its topology figure are established, and its natural vibration characteristics are computed. The computation results are verified by a modal test.
Transmission Errors and Backlash Analysis of a Single-Stage Cycloidal Drive Using Tooth Contact Analysis
Authors: Shih Yi-Pei , Sheen Bor-Tyng , Wu Kun-Yu , Lee Jyh-Jone
Published: November 2018

Cycloidal gear drives possess compact sizes, large reduction ratios, and low backlash. They are particularly suitable for applications in precise positioning and large output torque, for example, industrial robots and machine tools. Two main dynamic performances, transmission accuracy and backlash, is directly influenced by manufacturing errors. This paper aims to provide a direct method to effectively evaluate both performances. The mathematical models of transmission errors and backlash are established using the theory of gearing as well as tooth contact analysis. Three cases, considering profile modifications of the cycloidal gear and manufacturing errors, are evaluated to verify the correctness of the mathematical models.
A Motion Synthesis Approach to Solving Alt-Burmester Problems by Exploiting Fourier Descriptor Relationship Between Path and Orientation Data
Authors: Sharma Shashank , Purwar Anurag , Ge Q. Jeffrey
Published: November 2018

This paper presents a generalized framework to solve m-pose, n-path points mixed synthesis problems, known as Alt-Burmester problems, using a task-driven motion synthesis approach. We aim to unify the path and motion synthesis problems into an approximate mixed synthesis framework. Fourier descriptors are used to establish a closed-form relationship between the path and orientation data. This relationship is then exploited to formulate mixed synthesis problems into pure motion synthesis ones. We use an efficient algebraic fitting based motion synthesis algorithm to enable simultaneous type and dimensional synthesis of planar four-bar linkages.
Optimization of the Case Depth of a Cylinder Made With 4340 Steel by a Control of the Laser Heat Treatment Parameters
Authors: Fakir Rachid , Barka Noureddine , Brousseau Jean
Published: November 2018

This paper presents a numerical model able to control the temperature distribution along a 4340 steel cylinder heat-treated with Nd: YAG laser. The numerical model developed using the numerical finite element method, was based on a study of surface temperature variation and the adjustment of this temperature by a control of the heat treatment laser power. The proposed analytical approach was built gradually by (i) the development of a numerical model of laser heat treatment of the cylindrical workpiece, (ii) an analysis of the results of simulations and experimental tests, (iii) development of a laser power adjustment approach, and (iv) proposal of a laser power control predictor using neural networks. This approach was made possible by highlighting the influence of the fixed (non-variable) parameters of the laser heat treatment on the case depth, and has shown that it is possible by controlling the laser parameters to homogenize the distribution of the maximum temperature reached on the surface for a uniform case depth. The feasibility and effectiveness of the proposed approach leads to a reliable and accurate model able to guarantee a uniform surface temperature and a regular case depth for a cylindrical workpiece of a length of 50-mm and with a diameter of between 16-mm and 22-mm.
A New Plate Formulation Based on Triangular Isogeometric Analysis
Authors: Zareh Mehrdad , Qian Xiaoping
Published: November 2018

This paper presents application of rational triangular Bezier splines (rTBS) for developing Kirchhoff-Love plate elements in the context of isogeometric analysis. Triangular isogeometric analysis can provide the C1 continuity over the mesh including elements interfaces, a necessary condition in finite elements formulation based on Kirchhoff-Love shell and plate theory. Using rTBS and macro-element technique, we develop Kirchhoff-Love plate elements, investigate the convergence rate and apply the method on complex geometry. Obtained results demonstrate that the optimal convergence rate is achievable; moreover, this method is applicable to represent thin geometric models of complex topology or thin geometric models in which efficient local refinement is required.
The Submicron Fabrication Process for T Gate With a Flat Head
Authors: Su Xiaoyu , Ren Zhongjing , Sun Hao , Shi Yong , Pan Quan
Published: November 2018

T gate structure is traditionally manufactured with a valley in its head, which requires the thickness of the head layer to thicker than the height of foot layer. As is presented in this paper, an innovative submicron fabrication process is investigated for T gate structures to construct a flat head in order to get rid of that constraint. In detail, the reason why conventional T gate fabrication cannot manufacture a flat head is analyzed, and then a general process for flat head T gate structure is proposed considering various resist and structure materials. After that, a typical submicron sample has been manufactured using aluminum and NiTi. Furthermore, the particular photo resists and recipes adopted in that sample are considered. To clearly illustrate the proposed technique as well as verify its feasibility, top views of the structure under optical microscope along with the measurement results of thickness after every step are recorded. According to those experimental results, the valley in T gate’s head is proved to be avoided during fabrication.
Low-Cost Autonomous Underwater Vehicle (AUV) for Inspection of Water-Filled Tunnels During Operation
Authors: Pidić Almir , Aasbøe Egil , Almankaas Jørgen Simensen , Wulvik Andreas Simskar , Steinert Martin
Published: November 2018

This paper presents a new low-cost autonomous underwater vehicle (AUV) for inspection of water-filled tunnels. Deployment in flowing water tunnels and later retrieval at the tunnel exit produces a two-dimensional height vs. time plot of the tunnel, which can be compared to tunnel schematics. The resultant contour data is useful for maintenance planning and tunnel assessment in terms of internal clogging. This paper presents a proof-of-concept for traversing water filled tunnels by using water flow and variable buoyancy. Empirical data is collected in a scaled down version of one specific water supply tunnel in Norway.
On Locomotion of a Laminated Fish-Inspired Robot in a Small-to-Size Environment
Authors: Sharifzadeh Mohammad , Khodambashi Roozbeh , Zhang Wenlong , Aukes Daniel
Published: November 2018

Many different robots have been designed and built to work under water. In many cases, researchers have chosen to use a bioinspired platforms. In most cases, the main goal of the fish inspired robots has been set to autonomously swim and maneuver in an environment spacious compared to the fish’s size. In this paper, the identification & control of a low-cost fish-inspired robot is studied with goal of building a mechanism to not only swim in water but able to interact with its narrow environment. The robotic fish under study uses tail propulsion as main locomotion. Moreover, proper propulsion regimes are identified and used to model and control thrust generated by propulsion.
An Interdisciplinary Mixed-Method Approach to the Evaluation of a Novel Water Treatment Technology in Eastern Uganda
Authors: Burleson Grace , MacCarty Nordica , Sharp Kendra , Tilt Bryan
Published: November 2018

Researchers are calling on practitioners to use more robust mixed-method approaches in program and product evaluations in the global development sector. Using qualitative and quantitative research methods from both experimental engineering and applied anthropology fields can provide more holistic and accurate information regarding potential impact and application of a product or program in its actual usage context.

This paper presents a mixed-method approach for the evaluation of a new water treatment technology, the InStove Water Purifier. A combination of technical and ethnographic methods are used to estimate the product’s efficacy in a high-school dormitory in Mbale, a city in Eastern Uganda. Methods include participant observation, focal follow, time allocation and data collection of system parameters including fuel usage, flowrate, and temperature. Additionally, a holistic approach to water treatment implementation is applied by experimentally evaluating water storage treatment methods to prevent recontamination of water before its point-of-use.

This study highlights the importance of method triangulation and, more specifically, the value of ethnographic methods to evaluate engineering solutions. While two methods concluded statistically insignificant results (time allocation and fuel usage) due to limited sample size and duration of the study, this work emphasizes the value that comes from working closely with end-users in an uncontrolled experimental environment.

Informal interviewing during participant observation combined with time allocation and fuel usage data show a high potential for user acceptance due to the Purifier’s time and fuel savings (42% and 67% savings; respectively), increased water capacity, and reduction of emissions. Potential barriers to user adoption of the Purifier, identified in this study, include the trust required by users, lack of water outlet temperature control, and a size change of fuel wood. These findings have been reported to InStove, the manufacturer of the product, to begin design modifications to improve its potential impact to users.

Ultimately, this paper aims to encourage engineering practitioners to become more comfortable performing ethnographic methods and integrating qualitative data to more accurately evaluate their projects in the field and provide design changes that increase user adoption and sustained impact.
Validation of a Newly Proposed 3D Flexible Ring Tire Model Through Adams FTire Full-Vehicle Simulations
Authors: Li Bin , Yang Xiaobo , Yang James
Published: November 2018

Flexible ring tire models are widely used for vehicle durability and ride comfort analysis. In our previous research, a novel 3D flexible ring tire model was proposed, and the model’s parameter identification and predictability were illustrated based on various tire cleat tests. To further demonstrate its capability, this paper applies the tire model in a full-vehicle model for various full vehicle bump tests with different driving speeds and cleat orientations in Matlab programing. The tire model and the full-vehicle model are connected through a suspension system, with the suspension spring and damper along the vertical direction, and rigid attachment along the longitudinal and lateral directions. The predicted results are compared against ADAMS® full-vehicle FTire virtual tests with the same simulation conditions. The comparison variables include tire forces, vertical displacements, and suspension jounce movements. The results provide useful guidance for the design of vehicle suspension.
Modelling of Continuous Contact-Based Skating Technique
Authors: Gupta Varan , Patel Rohit , Khatait Jitendra P. , Kar I. N.
Published: November 2018

Quick locomotion has always been a challenge for humanoid robots. Most of the work has been done to improve the efficiency of the walking gaits. Recently, additional equipment like skates are increasingly being used to speed up location, but they also make the system highly unstable. This paper describes the development of a statically stable skating gait to facilitate movement across plain surfaces, such as roads and hard ice. The new gait utilises the non-holonomic nature of a wheel (or blade of an ice skate). The proposed motion of the skates on the ground plane enables it to propel the robot forward without lifting its leg. Kinematic and dynamic equations of an equivalent model are formulated. Further, the paper discusses the relationship between different input signals and their corresponding output gaits. Multibody dynamics software is then used to simulate and verify the results for various scenarios. The design of an equivalent model with three degrees of freedom is then analysed and discussed for practical testing. Finally, the algorithm was tested on a fabricated robot.
Multiphysics Modeling and Experimental Validation of Reconfigurable, E-Textile Origami Antennas
Authors: Shah Hamil , Inshaar Abdullahi , Zou Chengzhe , Chaudhari Shreyas , Alharbi Saad , Kiourti Asimina , Harne Ryan L.
Published: November 2018

Physical deformation mechanisms are emerging as compelling and simple ways to adapt radio frequency (RF) characteristics of antennas in contrast to digital steering approaches acting on topologically fixed antennas. Concepts of physical reconfigurability also enable exceptional capabilities such as deployable and morphing antenna arrays that serve multiple functions and permit compact transport with ease. Yet, the emergent concepts lack broad understanding of effective approaches to integrate conformal, electrically conductive architectures with high-compliance foldable frameworks. To explore this essential interface where electrical demands and mechanical requirements may conflict, this research introduces a new class of origami-based tessellated antennas whose RF characteristics are self-tuned by physical reconfiguration of the antenna shape. E-textile materials are used to permit large antenna shape change while maintaining electrical conductivity. Dipole and patch antennas are considered as conventional antenna platforms upon which to innovate with the e-textile origami concept. Multiphysics modeling efforts establish the efficacy of foldable antenna geometries for broad tailoring of the RF characteristics. Experiments with proof-of-concept antennas confirm the large adaptability of wave radiation properties enabled by the reconfiguration of the e-textile origami surfaces. The results suggest that e-textile antennas can be integrated into clothing and mechanical structures, providing a non-invasive way of quantifying deformation for a wide range of applications.
A Quasi-Static Model for Studying Physical Interaction Between a Soft Robotic Digit and a Human Finger
Authors: Haghshenas-Jaryani Mahdi , Wijesundara Muthu B. J.
Published: November 2018

This paper presents the development of a framework based on a quasi-statics concept for modeling and analyzing the physical human-robot interaction in soft robotic hand exoskeletons used for rehabilitation and human performance augmentation. This framework provides both forward and inverse quasi-static formulations for the interaction between a soft robotic digit and a human finger which can be used for the calculation of angular motions, interaction forces, actuation torques, and stiffness at human joints. This is achieved by decoupling the dynamics of the soft robotic digit and the human finger with similar interaction forces acting on both sides. The presented theoretical models were validated by a series of numerical simulations based on a finite element model which replicates similar human-robot interaction. The comparison of the results obtained for the angular motion, interaction forces, and the estimated stiffness at the joints indicates the accuracy and effectiveness of the quasi-static models for predicting the human-robot interaction.
Design and Prototyping of a Shape-Changing Rigid-Body Human Foot in Gait
Authors: Rolfe Tanner N. , Murray Andrew P. , Myszka David H.
Published: November 2018

Traditional ankle-foot devices such as prostheses or robotic feet seek to replicate the physiological change in shape of the foot during gait using compliant mechanisms. In comparison, rigid-body feet tend to be simplistic and largely incapable of accurately representing the geometry of the human foot. Rigidbody mechanisms offer certain advantages over compliant mechanisms which may be desirable in the design of ankle-foot devices, including the ability to withstand greater loading, the ability to achieve more drastic shape-change, and the ability to be synthesized from their kinematics, allowing for realistic functionality without a priori characterization of the external loading conditions of the foot. This work focuses on applying the methodology of shape-changing kinematic synthesis to design and prototype a multi-segment rigid-body foot device capable of matching the dynamic change in shape of the human foot in gait.
A Two-Tiered Grammatical Approach for Agent-Based Computational Design
Authors: Puentes Lucas , McComb Christopher , Cagan Jonathan
Published: November 2018

Early stages of the engineering design process are vital to shaping the final design; each subsequent step builds from the initial concept. Innovation-driven engineering problems require designers to focus heavily on early-stage design generation, with constant application and evaluation of design changes. Strategies to reduce the amount of time and effort designers spend in this phase could improve the efficiency of the design process as a whole. This paper seeks to create and demonstrate a two-tiered design grammar that encodes heuristic strategies to aid in the generation of early solution concepts. Specifically, this two-tiered grammar mimics the combination of heuristic-based strategic actions and parametric modifications employed by human designers. Rules in the higher-tier are abstract and potentially applicable to multiple design problems across a number of fields. These abstract rules are translated into a series of lower-tier rule applications in a spatial design grammar, which are inherently domain-specific. This grammar is implemented within the HSAT agent-based algorithm. Agents iteratively select actions from either the higher-tier or lower-tier. This algorithm is applied to the design of wave energy converters, devices which use the motion of ocean waves to generate electrical power. Comparisons are made between designs generated using only lower-tier rules and those generated using only higher-tier rules.
Reduced Order Model of Coaxial Vibrations of Electrostatically Actuated Double Wall Carbon Nanotubes: Frequency Response of Primary Resonance
Authors: Juarez Ezequiel , Caruntu Dumitru I.
Published: November 2018

In this paper, the Reduced Order Method (ROM) and the Method of Multiple Scales (MMS) are used to investigate the influences of dimensionless damping and voltage parameters on the amplitude-frequency response of an electrostatically actuated double-walled carbon nanotube (DWCNT). The forces responsible for the nonlinearities in the vibrational behavior are intertube van der Waals and electrostatic forces. Soft AC excitation and small viscous damping forces are assumed. Herein, the coaxial case is investigated. In this mode of vibration, the outer and inner carbon nanotubes move synchronously (in-phase) with the same maximum tip deflection. The DWCNT structure is modelled as a cantilever beam with Euler-Bernoulli beam assumptions since the DWCNT is characterized with high length-diameter ratio. The results shown assume steady-state solutions in the first-order MMS solution. The analytical approximate solutions provided by MMS are validated numerically by two-term (2T) Time Reponses and AUTO-07P. The two methods in this paper are found to be in excellent agreement at lower amplitudes. Additionally, the two methods are assessed for their advantages and limitations. The importance of the results in this paper are the effect of damping and voltage on the stability of the DWCNT vibration.
Nonlinear Resonance Behaviors of Rotating Pretwisted Cylindrical Panels
Authors: Yao Ming Hui , Niu Yan , Zhang Wei
Published: November 2018

The rotating blade is simplified as a rotating cylindrical panel with a presetting angle and a pretwist angle. Nonlinear dynamic behaviors of the rotating cylindrical panel under higher-frequency primary resonance and lower-frequency primary resonance in the presence of 1:2 internal resonance are discussed. We use the Green strain tensor to derive an strain-displacement relationship. Based on the first-order shear deformation theory, Hamilton principle and Galerkin method is utilized to acquire nonlinear ordinary differential equations of the system, which contains coupling between linear stiffness terms of the two transverse modes. The modulation equations are obtained by using the method of multiple scales. Matcont package is used to portray frequency-amplitude response curves and force-amplitude response curves of the system under higher-frequency primary resonance and lower-frequency primary resonance.
Motion/Force Transmissibility Based Performance Evaluation of a 6-DOF Parallel Robot With 2-DOF Active Joints
Authors: Mei Bin , Xie Fugui , Liu Xin-Jun , Luo Xuan
Published: November 2018

3-PP(Pa)S robot is a six degrees of freedom (DOFs) parallel mechanism with 2-DOF active planar joint. For the design and application of the 3-PP(Pa)S robot, it is essential to investigate the motion/force transmissibility of the robot. But previous studies of the motion/force transmissibility have mainly focused on the parallel robots with 1-DOF active joints and thus cannot be directly applied to the 3-PP(Pa)S robot. In this paper, input twist subspace, transmission wrench subspace and output twist subspace are investigated to build mathematical models of the twists and wrenches corresponding to the 2-DOF active planar joint. Afterwards, based on the previous established frame of the local transmission index, some extended performance evaluation indices are defined to describe the motion/force transmissibility of the 3-PP(Pa)S robot. On this basis, the singularity and motion/force transmissibility of this mechanism are investigated. The motion/force transmissibility evaluation method is meaningful and applicable for the 3-PP(Pa)S parallel robot with 2-DOF active joints and can be further applied to other mechanisms with multi-DOF active joints.
Visual Similarity to Aid Alternative-Use Concept Generation for Retired Wind-Turbine Blades
Authors: Kwon E. , Pehlken A. , Thoben K.-D. , Bazylak A. , Shu L. H.
Published: November 2018

This work is motivated by finding alternative uses for retired wind-turbine blades, which have limited disposal options. Two reuse concept-generation activities (CGA) conducted in German universities revealed difficulties with the parts’ large scale and seeing beyond their original use. Existing methods, e.g., using functional analogy, are less applicable, since for safety reasons, these parts should not be reused in the same function.

Therefore, this work explores the use of visual similarity to support reuse-concept generation. A method was developed that 1) finds visually similar images (VSI) for wind-turbine-blade photos; and 2) derives potential-reuse concepts based on objects that are visually similar to wind-turbine blades in these images.

Comparing reuse concepts generated from the two methods, VSI produced fewer smaller-than-scale concepts than CGA. While other qualities like feasibility depend on the specific photo selected, this work provides a new framework to exploit visual similarity to find alternative uses. As demonstrated for wind-turbine blades, this method aids in generating alternative-use concepts, especially for large-scale objects.
Tractor Cab Virtual Modeling and Ergonomic Evaluation Based on JACK
Authors: Wu Yiwei , Zhou Zhili , Xi Zhiqiang , Li Jishun
Published: November 2018

Aimed at the drawbacks of traditional method of spot evaluation for tractor cabs, such as low effectiveness and high expense, this paper established a new method of tractor cab design and evaluation, which included formulating ergonomic evaluation process, creating virtual models of tractor cab and operators, building virtual environment of tractor cab man-machine system and conducting ergonomic evaluation. The YTO-1604 wheeled tractor has been taken as the analysis object, the layouts of its seat, accelerator pedal, clutch pedal, brake pedal, gear shift lever, steering wheel and other major parts were optimized. The optimized model was created by UG, then it was imported into JACK, thus the object for analysis was created. To accommodate the Chinese tractor operator population, the 95th, 50th and 5th percentile virtual operator models which respectively stands for the big figure, medium figure and small figure of Chinese adult males for ergonomic evaluation were created in JACK, and the angular comfort range for human body joints were determined. The 50th percentile operator was adjusted to a cozy posture through human control module, with hands holding steering wheel, left foot naturally put on clutch pedal, while right foot flat placed on the floor. The operator was located to the h point of seat in the optimized cab model, thus the man-machine virtual environment was completely built. Then the reach zone of the 5th percentile operator and the visual field of the 95th percentile operator were generated, the 95th percentile operator’s comfort was evaluated and the forces of the 95th percentile operator’s spinal L4/L5 were calculated. The results showed that the gear shift lever, steering wheel and control panel were located in the accessible reach zones, conforming to manipulation requirements. Control panel and windshield (except for part of the side windshield which could be observed by moving head) were contained in the visual field, according with vision design standard. The overall comfort score of the 95th percentile operator’s different body parts was 24.5, which indicated that the operator was in good condition and the design conformed to physiological requirements. The lower back compression force of the 95th percentile operator was 742, representing a nominal risk of lower back injury for operators. Thus, the rationality of cab layout scheme was well verified. This paper provides a method for the ergonomic design and evaluation of tractor cabs.
Modeling Participation Behaviors in Design Crowdsourcing Using a Bipartite Network-Based Approach
Authors: Sha Zhenghui , Chaudhari Ashish M. , Panchal Jitesh H.
Published: November 2018

This paper studies the participation behaviors in design crowdsourcing by modeling associations between participants and design contests as a bipartite network. Such a network consists of two types of nodes, participant nodes and design contest nodes, and the links indicating participating relations. Our hypothesis is that participants’ decisions are interdependent. For example, one participant’s decision on whether to participate in a contest depends on whether other participants have participated in the same contest or not. To test the hypothesis, the exponential random graph model (ERGM) is adopted. ERGM enables the utilization of various network configurations (e.g., stars and triangles) to characterize different forms of interdependencies and identify the factors that influence link formation process. Using the field data of GrabCAD — an online design crowdsourcing platform, a case study is performed. Four groups of factors are found influential to participants’ behaviors in design crowdsourcing, including designer-related, contest-related, incentive-related and decision interdependence-related factors. Our results indicate the network-based approach can successfully identify the most important factors and quantify the interdependent effects. Our results reveal interesting features about the incentives of GrabCAD, e.g., the absolute amount of the first prize does not play a significant role in attracting participants whereas the fraction does, but negatively. These insights are useful to system designers for initiating effective crowdsourcing in support of product design and development.
Point-Based Virtual Environment for Detecting Scaffolding, Wearing, and Cracks of Furnace Walls
Authors: Shinozaki Yuki , Masuda Hiroshi
Published: November 2018

Maintenance of production facilities is important in various industries. Since production facilities degrade their original functions during their long life-cycle, it is necessary to periodically make deterioration diagnosis and renovate to restore functions. In recent years, the terrestrial laser scanner allows us to capture dense point-clouds from large production facilities. Point-based virtual environment is promising for supporting maintenance of production facilities. In this paper, we discuss the deterioration diagnosis of production facilities based on point-clouds when the original shapes of production facilities are unknown. As an example of production facilities, we consider the blast furnace, which is mainly used to produce metals from molten materials. We classify deterioration on the blast furnace as wearing, scaffolding, and cracks, and automatically detect them from point-clouds. In our method, the normal wall shape is estimated by fitting low-resolution B-spline surfaces to point-clouds, and deterioration is detected as the difference between the reference surface and the point-clouds. While wearing and scaffolding regions are relatively large, cracks are thin lines. In order to detect different scales of deterioration, we introduce the reference surfaces with multiple resolutions. In our experiments, the three types of deterioration could be successfully detected from dense point-clouds.
Optimal Design of Bi- and Multi-Stable Compliant Cellular Structures
Authors: Luo Quantian , Tong Liyong
Published: November 2018

This paper presents optimal design for nonlinear compliant cellular structures with bi- and multi-stable states via topology optimization. Based on the principle of virtual work, formulations for displacements and forces are derived and expressed in terms of stress and strain in all load steps in nonlinear finite element analysis. Optimization for compliant structures with bi-stable states is then formulated as: 1) to maximize the displacement under specified force larger than its critical one; and 2) to minimize the reaction force for the prescribed displacement larger than its critical one. Algorithms are developed using the present formulations and the moving iso-surface threshold method. Optimal design for a unit cell with bi-stable states is studied first, and then designs of multi-stable compliant cellular structures are discussed.
A Comparison of Control Strategies for Disruption Management in Engineering Design for Resilience
Authors: Wu Jiaxin , Wang Pingfeng
Published: November 2018

Managing potential disruptive events at the operating phase of an engineered system therefore improving the system’s failure resilience is an importance yet challenging task in engineering design. The resilience of an engineered system can be improved by enhancing the failure restoration capability of the system with appropriate system control strategies. Therefore, control-guided failure restoration is an essential step in engineering design for resilience. Considering different characteristics of disruptive events and their impacts to the performance of a system, effective control strategies for the failure restoration must be selected correspondingly. However, the challenge is to develop generally applicable guiding principles for selecting effective control strategies thus implementing the control-guided failure restorations. In this paper, a comparison of three commonly used control strategies for dynamic system control is conducted with the focus on the effectiveness of restoring system performance after the system has undergone different major disruptive events. A case study of an electricity transmission system is used to demonstrate the dynamic system modeling and the comparison of three control strategies for disruption management.
Nonlinear Analysis of Rigid Rotor System Supported by 2 Lobes Journal Bearing in Comparison With Circular Journal Bearing
Authors: Koondilogpiboon Nuntaphong , Inoue Tsuyoshi
Published: November 2018

The effect of 2 lobes journal bearing parameters such as L/D ratio and pad preload on the bifurcation of the rigid rotor is investigated in comparison with the circular bearing. Nonlinear bearing force in the equation of motion is obtained by solving Reynolds equation using the finite difference method. Shooting method and Floquet multiplier analysis are employed to obtain limit cycles and their stability. The results show that, for some bearing parameters, multiple limit cycles coexist at a specific shaft rotational speed range. Comparing with the circular bearing of same L/D ratio, the 2 lobes bearing without pad preload decreases the onset speed of instability and also decreases speed range from the onset speed of instability (Hopf) point to the limit point of the bifurcation (saddle-node) in the subcritical bifurcation case. Increasing the pad preload only increases the onset speed of instability significantly in the small L/D ratio case. For both circular and 2 lobes bearing, increasing the L/D ratio decreases the onset speed of instability and tends to change the type of the bifurcation from supercritical to subcritical.
Improved Differential Nullspace Matrix Method for the Dynamic Analysis of Multibody Systems
Authors: Kamiya Keisuke
Published: November 2018

This paper presents a novel method for motion analysis of rigid multibody systems. In general, dynamics of multibody systems is described by differential algebraic equations with Lagrange multipliers. For efficient and accurate analysis, it is desirable to eliminate the Lagrange multipliers and dependent variables. Methods called nullspace method and Maggi’s method eliminate the Lagrange multipliers by using the nullspace matrix for the constraint Jacobian. In a previous report, the author presented a method in which the nullspace matrix is obtained by solving a differential equation together with the equation of motion of the system. In that method QR decomposition is used. In this report, reduction in computational time with the LU decomposition is attempted. In addition, treatment of singular configurations for accurate analysis is presented. Validity of the presented method is confirmed via numerical examples.
Numerical Simulation of Yarn’s Snarl Motion Considering Self-Contact and its Experimental Verification
Authors: Takeuchi Hidetoshi , Inoue Tsuyoshi , Takagi Kentaro
Published: November 2018

A yarn has a flexible structure whose axial length is very long compared its diameter. When loose yarn twists at its end, the yarn intertwines with itself as shown in Fig. 1 to produce a shape called a snarl shape with motion referred to as snarl motion. The snarl shape sometimes cuts the yarn or reduces the yarn quality, and may reduce the productivity of textile machinery. As a preliminary step of handling snarl motion in the processes of textile machinery, this paper extends functions of a yarn model proposed in our previous study by appending a contact force and implementing a multithread computing method for fast simulation. The paper validates the yarn model by comparing the results of numerical simulation and experiment. Six-threads computing can make calculation at 5 times the rate possible with single-thread computing.
The Economies and Dimensionality of Prototyping: Value, Time, Cost and Fidelity
Authors: Tiong Edward , Seow Olivia , Teo Kenneth , Silva Arlindo , Wood Kristin L. , Jensen Daniel D. , Yang Maria C.
Published: November 2018

Economic use of early stage prototyping is of paramount importance to companies engaged in the development of innovative products, services and systems because it directly impacts their bottom-line [1, 2]. There is likewise a need to understand the dimensions and lenses that make up an economic profile of prototypes. Yet, there is no reliable understanding of how resources expended and views of dimensionality across prototyping translate into value [3, 4]. To help practitioners, designers, and researchers leverage prototyping most economically, we seek to understand the tradeoff between design information gained and the resource expended into prototyping to gain that information [5]. We investigate this topic by conducting an inductive study on industry projects across disciplines and knowledge domains, while collecting and analyzing empirical data on their physical prototyping process [3]. Our research explores ways of quantifying prototyping value and reinforcing the asymptotic relationship between value and fidelity [6]. Most intriguingly, it reveals insightful heuristics that practitioners can exploit to generate high value from low and high fidelity prototypes alike.
Vibration Analysis of Linear Beam With Moving Loads Based on Riccati Transfer Matrix Method for Multibody Systems
Authors: Sun Lu , Rui Xue , Bestle Dieter , Wang Guoping , Zhang Jianshu , Rui Xiaoting
Published: November 2018

The paper presents the dynamic response of an Euler-Bernoulli beam supported by an elastic foundation and subjected to a moving step load. The Riccati transfer matrix method for linear multibody systems (Riccati MSTMM) is employed to find eigenfrequencies and mode shapes of the supported beam. A comparison of results obtained with the finite element method (FEM) indicates that the Riccati MSTMM is more accurate when using the same number segments. Based on these results, the dynamic response of the beam with moving step load is investigated for different propagation velocities by mode superposition, and the effect of loads is discussed.
Toying With Design: Experiencing Design for Rapid Prototyping Using Mini-Fabrication Exercises
Authors: Banerjee Siddharth , Carithers Caleb , Chavan Aniket , Ramanujan Devarajan , Ramani Karthik
Published: November 2018

This study explores the use of mini-fabrication exercises for helping students learn design for rapid prototyping in computer-aided design and prototyping courses in engineering curricula. To this end, we conducted mini-fabrication exercises in ME444 — an undergraduate course at Purdue University. The exercises provide hands-on exposure to design for rapid prototyping principles using simplified design problems. We developed two mini-fabrication exercises in ME444; (i) gear pair design & box design using laser cutting, and (ii) toy catapult design using stereolithography printing. These exercises were tested in a classroom-setting with 51 undergraduate students. Results show the mini-fabrication exercises facilitated students’ learning of geometric dimensioning & tolerancing, part sizing, and material properties in laser cutting and stereolithography printing.
Development and Optimization of the Bridge-Lever-Type Hinge Mechanisms
Authors: Chen Fangxin , Gao Futian , Du Zhijiang , Yang Miao , Dong Wei
Published: November 2018

A displacement amplifier based on the bridge-lever-type hinge mechanisms is developed and optimized in this paper. The proposed design not only maintains a compact and symmetrical structure, but also features a high amplification ratio. To reduce the displacement loss and enhance the load capacity of the amplifier, the hybrid flexure hinges are employed in the novel design. The analyzed models for the amplification ratio and resonance frequency calculation are established based on the matrix method and Lagrangian method respectively, which are verified by finite-element analysis (FEA) and displacement experiment. Based on the established model, an optimization via the NSGA-II algorithm is performed to estimate the performance of the hinge mechanism.