bluuebunny/crossref_metadata_2025_split huggingface dataset:
Design and Simulation of a Novel High-Speed Omnidirectional Fully-Actuated Underwater Propulsion Mechanism
Authors: Njaka Taylor , Brizzolara Stefano , Ben-Tzvi Pinhas 
Published: November 2019

Abstract
This paper details the design and simulation of a novel position control mechanism for marine operations or inspection in extreme, hostile, or high-speed turbulent environments where unprecedented speed and agility are necessary. The omnidirectional mechanism consists of a set of counter-rotating blades operating at frequencies high enough to dampen vibrational effects on onboard sensors. Each rotor is individually powered to allow for roll control via relative motor effort and attached to a servo-swashplate mechanism, enabling quick and powerful manipulation of fluid flow direction in a hull’s coordinate frame without the need to track rotor position. The mechanism inherently severs blade loads from servo torques, putting all load on the main motors and minimizing servo response time, while exploiting consistent blade momentum to minimize the corresponding force response time. The mechanical design and kinematic analysis of each subsystem is presented, followed by kinematic and hydrodynamic analysis of the hull and surrounding fluid forces during various blade maneuvers. Special maneuvers are verified using Computational Fluid Dynamic (CFD) software. Finally, a controller is constructed with decoupled parameters for each degree of freedom.
Robotics Simulator for Development and Verification of Swarm Behaviors
Authors: Hart Shae T. , Metzger Nathan J. , Reese Maximilian E. , McDonald Robert T. , Neumann Michael A. , Kitts Christopher A. 
Published: November 2019

Abstract
Swarm control strategies allow for decentralized control of many simple robots to perform collective behaviors based on local interactions. We have created a new platform for developing and exploring swarm behaviors, supporting both simulation and experimental verification. The platform, designed entirely in Simulink, provides a simple implementation with satisfactory dynamics to replicate experimental trials on Santa Clara University’s Robotic Systems Laboratory’s Low-Cost Indoor Testbed. The platform allows for seamless transitions from simulation to experimentation on the testbed. The platform is currently equipped with attract, disperse, obstacle avoidance, and go-to behaviors which have been verified both in simulation and on the experimental testbed. Additionally, a composite behavior, flocking, composed of attract and go-to behaviors is presented to demonstrate the flexibility of the simulator. Future work will expand the available behaviors to include swarm adaptive navigation behavior primitives like minima and maxima finding as well as contour and ridge following.
A Deep Learning Based Approach to Predict Sequential Design Decisions
Authors: Rahman Molla Hafizur , Xie Charles , Sha Zhenghui 
Published: November 2019

Abstract
During a design process, designers iteratively go back and forth between different design stages to explore the design space and search for the best design solution that satisfies all design constraints. For complex design problems, human has shown surprising capability in effectively reducing the dimensionality of design space and quickly converging it to a reasonable range for algorithms to step in and continue the search process. Therefore, modeling how human designers make decisions in such a sequential design process can help discover beneficial design patterns, strategies, and heuristics, which are important to the development of new algorithms embedded with human intelligence to augment computational design. In this paper, we develop a deep learning based approach to model and predict designers’ sequential decisions in a system design context. The core of this approach is an integration of the function-behavior-structure model for design process characterization and the long short term memory unit model for deep leaning. This approach is demonstrated in a solar energy system design case study, and its prediction accuracy is evaluated benchmarked on several commonly used models for sequential design decisions, such as Markov Chain model, Hidden Markov Chain model, and random sequence generation model. The results indicate that the proposed approach outperforms the other traditional models. This implies that during a system design task, designers are very likely to reply on both short-term and long-term memory of past design decisions in guiding their decision making in future design process. Our approach is general to be applied in many other design contexts as long as the sequential design action data is available.
Optimization of Parts Consolidation for Minimum Production Costs and Time Using Additive Manufacturing
Authors: Nie Zhenguo , Jung Sangjin , Kara Levent Burak , Whitefoot Kate S. 
Published: November 2019

Abstract
This research presents a method of evaluating and optimizing the consolidation of parts in an assembly using metal additive manufacturing (MAM). The method generates candidates for consolidation, filters them for feasibility and structural redundancy, finds the optimal build layout of the parts, and optimizes which parts to consolidate using a genetic algorithm. Optimal results are presented for both minimal production time and minimal production costs, respectively. The production time and cost model considers each step of the manufacturing process, including MAM build, post-processing steps such as support-structure removal, and assembly. It accounts for costs affected by parts consolidation, including machine costs, material, scrap, energy consumption, and labor requirements. We find that developing a closed-loop filter that excludes consolidation candidates with structural redundancy dramatically reduces the number of candidates to consider, thereby significantly reducing convergence time. Results show that, when increasing the number of parts that are consolidated, the production cost and time at first decrease due to reduced assembly steps, and then increase due to additional support structures needed to uphold the larger, consolidated parts. We present a rationale and evidence justifying that this is an inherent tradeoff of parts consolidation that generalizes to most types of assemblies. Subsystems that can be oriented with very little support structures, or have low material costs or fast deposition rates can have an optimum at full consolidation; otherwise, the optimum is likely to be less than 100%. The presented method offers a promising pathway to minimize production time and cost by consolidating parts using MAM. In our test-bed results on an aircraft fairing produced with powder-bed electron-beam melting, the solution for minimizing time is to consolidate 48 components into three discrete parts, which leads to a 33% reduction in unit production time. The solution for minimizing production costs is to consolidate the components into five discrete parts, leading to a 28% reduction in unit costs.
Experimental Investigations Into Broadband Vibration Absorption of Metastructures With Lattice Designs
Authors: Tempelman Joshua R. , Myers Audun , Yesilli Melih C. , Khasawneh Firas A. 
Published: November 2019

Abstract
Enhancements in manufacturing technologies, especially 3D-printing, have enabled the production of intricate micro-scale, elastic meta-structures. This study explores the broadband vibration absorption characteristics of these structures for three different geometries: simple-cubic periodic geometries as well as the more-involved diamond and octet-truss micro-lattice geometries. Broadband absorption is experimentally achieved for the basic cubic geometries with band gaps approximately 3000 Hz in width. A band gap of 3500 Hz is found in the octet-truss lattice with a 5% mass increase. The diamond lattice achieves a band gap width which doubles its cubic counterparts (6500 Hz), but only at a cost of a 4% mass increase. We compare the experimental findings to the theoretical results obtained by modeling the structure as a discrete, lumped mass system and employing modal analysis and transfer-function matrix methods. These comparisons show a mismatch between the theoretical and the experimental frequency responses. This mismatch is attributed to the inconsistencies inherent to 3D-printing processes, and to the need for more accurate modeling of the lattice structures.
Research Progress and Development Tendency of Transfer Matrix Method for Multibody Systems (Rui Method)
Authors: Rui Xiaoting , Wang Xun , Zhang Jianshu , Gu Junjie , Zhang Shujun 
Published: November 2019

Abstract
The transfer matrix method for multibody systems, known as the “Rui method”, is a new method for dealing with multibody system dynamics, which does not need the global dynamics equations of the system, keeps high computational speed, and is highly formalized programming. This method has been widely applied to scientific research and key engineering of many complex mechanical systems in more than 50 research fields. The following aspects regarding the transfer matrix method for multibody systems are reviewed in this paper: history, basic principles, formulas, algorithm, and applications in engineering. Some hot topics in this field are also reviewed and prospected, mainly regarding to the improvement of the computational stability and efficiency.
Periodic Motions in a Single-Degree-of-Freedom System Under Both an Aerodynamic Force and a Harmonic Excitation
Authors: Yu Bo , Luo Albert C. J. 
Published: November 2019

Abstract
In this paper, a semi-analytical approach was used to predict periodic motions in a single-degree-of-freedom system under both aerodynamic force and harmonic excitation. Using the implicit mappings, the predictions of period-1 motions varying with excitation frequency are obtained. Stability of the period-1 motions are discussed, and the corresponding eigenvalues of period-1 motions are presented. Finally, numerical simulations of stable period-1 motions are illustrated.
Effect of Team Size on Problem-Solving and Solution Quality: An Empirical Study
Authors: Jacobs Seth , Pfarr Matthew , Fazelpour Mohammad , Koroma Abdul , Mesfin Tseday 
Published: November 2019

Abstract
The size of a team can affect how they tackle a design problem and solution quality. This paper presents a protocol study of the impact of team size on problem-solving and design solution quality. The protocols are coded with micro-strategies, and macro-strategies, and final solutions are scored using a rubric of meeting constraints, manufacturability, feasibility, and cost. The results show that the larger design team sizes analyze design solutions more frequently and propose solutions less than the smaller design teams. Among the three team sizes of 1, 3, and 5, the teams of three designers scored the best on final designs. These teams used a fair amount of both proposing solutions and analyzing solutions of micro-strategies. The teams of 5 designers use backtracking macro-strategies more frequent than teams of 3 and one because as the team size increases, more time is spent among team members to discuss previous ideas.
A Proposed Hybrid Laser Quenching Process, and Investigation of its Three-Dimensional Forming Error
Authors: Nishida Hiromichi , Manabe Yuki , Hirogaki Toshiki , Aoyama Eiichi 
Published: November 2019

Abstract
In this research, we focus on heat treatment, specifically during the downsizing of production systems. We devise a method designed to remedy the problem of quenching for thin plates, by using a small semiconductor laser. In this report, we investigated a method to reduce the influence, deformation amount, and three–dimensional (3D) distortion error of residual stress that occurred when a laser test was performed on a metal test piece. Regarding the residual stress, the specimen was burned out by continuous scanning. Its residual stress showed a tendency to fade as the specimen was scanned at lower speeds. We found it was possible to reduce deformation by restraining the specimen with the jig, but that 3D strain error under this constrained state remained of the same order as it was in the unconstrained state. In addition, by restraining the test piece with a jig, it was possible to prevent reverse deformation (Buckling Mechanism).
Exhaustive Synthesis and Analysis of Automotive 2-Stage Planetary Transmission Designs
Authors: Karhula Henri , Nicolai Mike , Desmet Wim 
Published: November 2019

Abstract
Most modern automatic automotive transmissions are complex mechanical systems composed of multiple planetary gearsets that are connected by shafts, clutches and brakes. Creating a design that supports the desired transmission ratios while requiring a minimal amount of components is a challenging task that is commonly tackled by an engineer with experience and intuition.
This paper introduces an approach for the exhaustive synthesis of automotive transmissions composed of two planetary gearsets, two clutches and two brakes that can be deployed in automotive drivetrains. By modeling the components of an automotive transmission based on their possible mechanical connections and additional user-defined specifications a constraint satisfaction problem is derived. An iterative solving process exhaustively generates all possible transmission design with the specified set of components. Further the generated designs are filtered and analyzed such that the designer is served only with unique, valid and useful transmission designs. Finally a set of generated, novel 4-speed transmission designs is presented.
A Shape Memory Alloy Driven Crawling Robot Utilizing a Bistable Mechanism
Authors: Meng Lingda , Kang Rongjie , Gan Dongming , Chen Guimin , Dai Jian S. 
Published: November 2019

Abstract
Shape memory alloys (SMA) can generate displacement and force via phase change and have been widely used as actuators in robotics due to their light weight and ease of control. This paper proposes a SMA-driven crawling robot which activates antagonistic SMA springs alternately through a mechanical on-off logic switching system. By introducing a cam based bistable mechanism, elastic energy is stored and released to regulate the reciprocating motion of a slider in the robot. Meanwhile, the robot feet with anisotropic friction surface are employed to convert the reciprocating motion of the slider to unidirectional locomotion of the robot. The static model of the SMA and control logic of the robot are analyzed and validated through experiments.
Effect of Rider Posture on Bicycle Comfort
Authors: Polanco Alejandra , Marconi Edoardo , Muñoz Luis , Suárez Daniel , Doria Alberto 
Published: November 2019

Abstract
Cyclists are exposed to vibration due to road roughness. The levels of vibration that the cyclists experience have a major effect on comfort and depend on the bicycle, rider and road characteristics. It is known that the posture of the cyclist has a relevant effect on the bicycle-cyclist system vibration response. Nevertheless, this effect has been scarcely quantified. This study focuses on the measurement of the effect of body posture on comfort while riding a bicycle.
A laboratory methodology based on the measurement of the impulsive response of sensitive points of the bicycle was implemented to predict the comfort of cyclists on the road. The posture on the sagittal plane was verified during the tests. The methodology was implemented to predict the comfort of two cyclists riding a city bicycle in two postures: upright and bent forward.
Experimental results showed that in the bent forward posture the acceleration levels had a significant increment for the handlebar stem and a non-significant increment for the seatpost.
Stochastic Simulation of Turbine Engine Component Under Aleatory and Epistemic Uncertainty
Authors: McKeand Austin M. , Gorguluarslan Recep M. , Choi Seung-Kyum 
Published: November 2019

Abstract
Quantifying the uncertainty associated with material properties in engineering analysis has become more important in the design of many components in the aerospace field. In this study, a new method is proposed to account for the uncertainty associated with the elastic modulus of materials used in aerospace components. A computerized tomography (CT) scanner is used to capture the porosity of the material and the corresponding uncertainty is represented with epistemic uncertainty. A stochastic upscaling method is used to find a homogenized modulus that correctly reflects the effect of defects inside of the material. This homogenized elastic modulus is then applied to a constructed finite-element model of an aerospace component so that the stochastic behavior can be correctly quantified. Simulations of the selected example, i.e., turbine blade, include both aleatory and epistemic uncertainty; thus, a P-Box is introduced to represent the response of the simulations. The stochastic upscaling method is applied again to match the P-Box response of the coarse scale model to that of the fine scale model. The obtained results show that the proposed framework not only significantly reduces complexity of the given engineering problem, but also produces accurate results which include both aleatory and epistemic uncertainty.
Computational Design of a Personalized Artificial Spinal Disc With a Data-Driven Design Variable Linking Heuristic
Authors: Yu Zhiyang , Shea Kristina , Stanković Tino 
Published: November 2019

Abstract
A personalized, 3D printed, multi-material artificial spinal disc is expected to not only achieve personalized anatomical fit, but also to restore the natural mechanics of the implanted spinal segment. However, the necessary structure for disc design is not explored and optimizing the design is challenging due to the high-dimensional search space provided by the material distribution precision of multi-material 3D printing as well as necessary nonlinear finite element simulation. Therefore, this study explores the feasibility of two multi-material spinal disc designs and a clustering-based design variable linking method to achieve efficient and effective optimization. The optimization goal is to enable the implant to have natural stiffnesses for five loading cases. The results show that a biomimetic fiber network is necessary for the disc design. Moreover, the optimization performance of the heuristic derived from a clustering-based method is shown to be a good trade-off between the objective function value and the computational time.
Design of a Triad-Pod Kinematic Flexure Mount for a Primary Mirror in Space Telescope at Cryogenic Temperature
Authors: Huo Tonglong , Yu Jingjun , Zhao Hongzhe 
Published: November 2019

Abstract
The paper mainly proposed a novel kinematic triad-pod flexure mount for supporting a primary mirror in space. This kind of mount is constructed by three identical pods, each of them is consisted of four rotation flexures with virtual rotation center. The mount can realize great releasement of thermal stress effect on primary mirror caused by CTE (Coefficient of Thermal Expansion) mismatch between baseplate and mirror at cryogenic temperature. Based on principles of kinematic design, the paper firstly proposes a mount configuration with three pods arranged with inclined angle. Then, the structure of pod is designed in detail, and compliance model is established. A study case is employed to illustrate how to design a triad-pod mount with higher supporting stiffness and large radialcompensate compliance. Finally, simulations by FEM are implemented to verify and analyze the performances of the proposed mount. The results demonstrate that the mount can further reduce the thermal stress in primary mirror while maintaining nearly indistinctive supporting stiffness than traditional three-bipod mount. Hence, the proposed mount can provide foundation to achieve a mount with greater performances for supporting a large-aperture mirror at a wider range of temperature.
A Novel Hierarchical Framework for Uncertainty Analysis of Multiscale Systems Combined Vine Copula With Sparse PCE
Authors: Xu Can , Liu Zhao , Tao Wei , Zhu Ping 
Published: November 2019

Abstract
Uncertainty analysis is an effective methodology to acquire the variability of composite material properties. However, it is hard to apply hierarchical multiscale uncertainty analysis to the complex composite materials due to both quantification and propagation difficulties. In this paper, a novel hierarchical framework combined R-vine copula with sparse polynomial chaos expansions is proposed to handle multiscale uncertainty analysis problems. According to the strength of correlations, two different strategies are proposed to complete the uncertainty quantification and propagation. If the variables are weakly correlated or mutually independent, Rosenblatt transformation is used directly to transform non-normal distributions into the standard normal distributions. If the variables are strongly correlated, multidimensional joint distribution is obtained by constructing R-vine copula, and Rosenblatt transformation is adopted to generalize independent standard variables. Then the sparse polynomial chaos expansion is used to acquire the uncertainties of outputs with relatively few samples. The statistical moments of those variables that act as the inputs of next upscaling model, can be gained analytically and easily by the polynomials. The analysis process of the proposed hierarchical framework is verified by the application of a 3D woven composite material system. Results show that the multidimensional correlations are modelled accurately by the R-vine copula functions, and thus uncertainty propagations with the transformed variables can be done to obtain the computational results with consideration of uncertainties accurately and efficiently.
Design and Analysis of Synchronous Joint for SAR Antenna Deployable Mechanism
Authors: Li Duanling , Dong Kaijie , Wang Xingze , Li Biao , Su Zhou 
Published: November 2019

Abstract
Synchronous joints are an important part of the SAR antenna deployment mechanism. They are the key to the synchronized deployment of antenna. By means of mechanism combination and deformation, a new type of synchronous joint with a precise cable drive system is designed in order to meet the requirements of SAR antenna deployment mechanism. This study mainly focuses on the design of the synchronous joint, including the system design and the precise cable drive system design. By applying a preload to the drive cable, the transmission gap is reduced, and the accuracy and efficiency of transmission are improved.
This paper focuses on the theoretical calculation and analysis of the preload and system stiffness of the precise cable drive system. Based on the Euler equation of the flexible friction drive, the stiffness formula of the cable drive system is derived. In addition, the main design parameters affecting the stiffness of the cable drive system are analyzed parametrically.
The comparison between the results obtained from the system stiffness experiment and the theoretical calculation result indicates that the experimental values are slightly smaller than the theoretical values, and the trend of change is basically consistent. This experiment therefore verifies the validity of the stiffness calculation formula and theoretical analysis.