bluuebunny/crossref_metadata_2025_split huggingface dataset:
Circumferential Wrinkling of Elastic Cylinders With Negative Surface Tension
Authors: Ru C.Q. 
Published: November 2022

Abstract
The present paper studies the critical condition for negative surface tension-driven circumferential wrinkling of soft cylinders based on the linearized Steigmann–Ogden model of surface elasticity. A simple negative surface tension-mode number relation is derived explicitly for arbitrary Poisson ratios of the cylinder and its surface layer and their shear modulus ratio, on which the critical surface residual strain and the associated mode number can be determined easily. For an incompressible solid cylinder with an incompressible thin surface layer, the critical values of surface residual strain and the mode number predicted by the present model are in good agreement with available numerical results based on the popular neo-Hooken nonlinear model for a wide range of material and geometrical parameters. In addition, the critical condition for circumferential wrinkling of the inner surface of a cylindrical hole within an infinite body is also derived. The present work addresses the key role of negative surface tension in circumferential wrinkling of soft cylinders and offers supporting evidence for the efficiency and accuracy of the linear Steigmann–Ogden model for the determination of the critical values for circumferential wrinkling.
Effect of Sliding Velocity on UHMWPE and VEXLPE Friction Against CoCr in Multidirectional, Serum Lubricated Conditions
Authors: Saikko Vesa , Morad Omar , Viitala Raine 
Published: November 2022

Abstract
The recently introduced four-station friction RandomPOD device was utilized in multidirectional, circular translation pin-on-disk (CTPOD) tests. The effect of sliding velocity on friction with orthopaedic bearing materials was studied. The tests included UHMWPE and VEXLPE pins against polished CoCr disks in serum lubrication at 37 °C. In the constant velocity tests, the sliding velocities used were from 5 to 50 mm/s at intervals of 5 mm/s. The test length with each velocity was 24 h. In the constant acceleration tests, the velocity steadily increased from 0 to 50 mm/s in 24 h. In all tests, the sample size was 4. No strong effect of velocity on friction was observed. This indicated a boundary lubrication mechanism. With sliding velocities above 10 mm/s, VEXLPE showed significantly lower friction than UHMWPE. The finding was in agreement with earlier dynamic RandomPOD tests. Clinically, the use of VEXLPE may result in lower frictional heating.
Inconstant Empathy—Interpersonal Factors That Influence the Incompleteness of User Understanding
Authors: Li Jie , Hölttä-Otto Katja 
Published: November 2022

AbstractEmpathy can help designers discover and fulfill users’ latent needs in design, which can lead to better design solutions. To achieve deep user understanding, designers utilize their ability to empathize with users. However, empathy is always incomplete and inconstant in user understanding. This study applies a quantitative behavioral empathy measure to a case of designers attempting to understand the needs of users of a future semi-autonomous vehicle technology. In total, 16 designers and 48 users are involved. We study how interpersonal differences between designers and users and different users’ mental content impact the level of empathic understanding. Specifically, these factors are national cultural differences, visiting experience, binary gender differences, the relationship between users and designers, and user mental content types. The results show that cultural differences and visiting experiences significantly affect designers’ empathic accuracy and emotional tone accuracy in both physical and online interviews. These influences vary depending on contextual factors that are related to the participant's own experience and the experiment itself.
The Effect of Potential Analogies and Negative Issues on Creative Designs
Authors: Casakin Hernan , Koronis Georgios , Silva Arlindo 
Published: November 2022

Abstract
The study explored ways in which briefs can be structured to support creative design outcomes. The procedure involved a controlled, yet analytical experiment carried out in a university setting to test the use of analogical reasoning under different conditions to enhance the creativity of design solutions. The first goal was to verify whether visual and text analogies contribute to enhancing design creativity, measured by novel and useful solutions. The second goal was to explore the use of visual and text analogies in creative designs when instructions to formulate negative statements about the problem were provided. A final goal was to test whether correlations exist between the students’ self-reported creativity and their design outcomes scores. 179 first-year undergraduate students participated in this study. The results showed that design briefs with specific instructions to use text or visual analogies yielded highly novel outcomes. However, when text or visual analogies were triggered by statements concerning negative issues of the design problem, more useful outcomes were produced. Moreover, significant relationships were found between self-perceived creativity and the novelty of the outcomes generated in the visual and text analogy briefs. It is suggested that both types of analogies should be employed as effective design studio pedagogical tools to enhance creativity. Negative statements should be considered when the design goal is to improve existing features of current solutions.
Sensitivity Analysis of a Suspended Cable-Driven Parallel Robot to Design Parameters
Authors: Paty Thibaut , Binaud Nicolas , Wang Hong , Segonds Stéphane 
Published: November 2022

Abstract
Cable-driven parallel robots (CDPRs) are system driven exclusively by cables, giving them advantages in operation. However, this also introduces complexity into their mechanical behavior. Indeed, the cable elasticity is affected by a hysteresis phenomenon. There is therefore an uncertainty about the actual value of the cable’s Young’s modulus. However, uncertainty analysis on design parameters of CDPR has not been conducted yet. So, this article first introduces a new modeling of CDPRs allowing to take in consideration the sagging of the cables while considering different pulley architectures as well as the cable dead length between the winch and the pulley. Then, a sensitivity analysis of the main design parameters on the positioning error of the moving platform (MP) is performed through a design of experiments conducted on a suspended CDPR with four cables. For this purpose, the variation of the Young’s modulus of the cables is determined. This allows to quantify and to rank the effects on the theoretical MP pose error of important design parameters that are the type of pulley joint, cable’ Young’s modulus, the cable mass, and the MP mass. This study is conducted for different sizes of CDPR. The results obtained show that the evolution of the effects of the design parameters is not the same depending on the size of the CDPR. Technical major considerations are derived from the presented results as guidelines for CDPR designer, keeping the modeling simple but robust enough for real-time control of CDPRs.
A Variable Stiffness End-of-Arm Tooling Mechanism to Enhance Dynamic Task Capabilities of Robotic Manipulators
Authors: Jujjavarapu Sri Sadhan , Manjunatha Hemanth , Esfahani Ehsan Tarkesh 
Published: November 2022

Abstract
Variable stiffness end-of-arm actuators can add dynamic manipulation capabilities to stiff manipulators and simultaneously enhance safety. The presence of an elastic element in these actuators can be used for absorbing impact energy; or storing energy and utilizing it for performing explosive tasks. The major challenge with variable stiffness actuators is to control their position and stiffness simultaneously to achieve optimal task performance. In this paper, we present an end-of-arm variable stiffness mechanism (VSM) for performing dynamic tasks. We formulate the task as an optimal control problem and numerically solve for the task-specific stiffness profile. We demonstrate the usability of the optimization problem in exploiting the dynamics of the VSM during an explosive hammering task and demonstrate that the time-varying stiffness profile can store energy and leads to improved task performance. As a result, the hammer attains twice as much velocity with variable stiffness compared to fixed stiffness. The hammering performance is further improved by optimizing task completion time and hammer velocity. Moreover, we demonstrate that the VSM stiffness plays a crucial role in minimizing the impact forces transferred to the robot. This paper presents the optimal trajectory and stiffness profile achieved through numerical optimization and then evaluates the proposed mechanism using experiments.
Dynamic Stiffness Matrix With Timoshenko Beam Theory and Linear Frequency Solution for Use in Compliant Mechanisms
Authors: Ling Mingxiang , Zhou Hao , Chen Liguo 
Published: November 2022

Abstract
The kinetostatic and dynamic formulation of planar-compliant mechanisms is investigated by making use of the dynamic stiffness method based on Timoshenko beam theory. This research is prompted by the significance of considering both the shear deformation and rotary inertia for short and thick flexure beams widely used in compliant mechanisms. We investigate the problem by developing the frequency-dependent dynamic stiffness matrix with the pseudo-static characteristic for a threefold purpose. The first is to show that a closed-form dynamic stiffness matrix of flexure beams in power series of frequency including the shear deformation and rotary inertia is effective that is parameter-insightful and from a computational standpoint concise. Second, a programmable stiffness and mass assembling procedure is developed to build the kinetostatic and dynamic model for compliant mechanisms in a general sense. The third target is to accelerate the calculation efficiency of dynamic stiffness model by employing a linear solution strategy of natural frequencies which is beneficial for parameter optimization iteration. The presented approach is demonstrated by applying the parameter influence analysis and dimension synthesis of a bridge-type compliant mechanism widely used in micro-displacement and/or force amplifications
Teaching Machine Learning for Analysis and Design to Mechanical Engineering Students
Authors: Du Xiaoping , Yin Jianhua 
Published: November 2022

Abstract
Machine learning has become pervasive in mechanical engineering and has been identified as a key skill required by current and future careers. It is crucial to include machine learning in the mechanical engineering curriculum to keep up with the quick-changing pace of the industry. One solution is to offer a new machine learning course specifically targeting mechanical engineering students. In this paper, we discuss the needs and objectives of machine learning education in mechanical engineering. We also show the challenges in applying machining learning in mechanical engineering and how to deal with the challenges in teaching the subject. We then report what we have done in developing a new machine learning course and using machine learning in engineering analysis and design. We demonstrate that using appropriate examples, case studies, and projects is one of the best ways to teach and learn machine learning. Our experiences provide useful information to other instructors who teach or intend to teach the same and related courses.
Non-Smooth Dynamics of Tapping Mode Atomic Force Microscopy
Authors: Belardinelli Pierpaolo , Chandrashekar Abhilash , Alijani Farbod , Lenci Stefano 
Published: November 2022

Abstract
This paper investigates the nonlinear dynamics in tapping-mode atomic force microscopy (AFM) with tip-surface interactions that include Van der Waals and Derjaguin-Müller-Toporov contact forces. We study the periodic solutions of the hybrid system by performing numerical pseudo-arclength continuation. The overall dynamical response scenario is evaluated via bifurcation loci maps in the set of parameters of the discontinuous model. We showcase the influence of different dissipation mechanisms activated when the AFM is in contact or out-of contact with the sample. The robustness of the stable solution in the repulsive regime is studied via local and global analyses. The impacting non-smooth dynamics framed within a higher-mode Galerkin discretization is able to capture windows of irregular and complex motion.
The Amount of Warning Stimulus Time Required to Prepare for a Hard-Breaking Event
Authors: Lenneman Gabe , Lenneman John , Chagdes James 
Published: November 2022

Abstract
Autonomous shuttles are becoming a widely used form of public transportation. While autonomous shuttles have advantages to improve safety, potential riders have expressed concerns about falls and injuries sustained during braking events. In the current study we investigated the effects of multiple warning design parameters, including the modality and the temporal aspects of the warning stimulus, on balance maintenance during a simulated hard braking event. Two warning stimuli were used — an auditory stimulus and a visual stimulus. We investigated the effect of the timing of the warning in an attempt to determine how differences in warning time affect preparation for a simulated hard braking event and subsequent maintenance of balance throughout the event. The warning stimuli were presented 200–750 ms prior to the simulated hard braking. We found that participants had more time to prepare for the simulated braking event when presented with the auditory stimulus versus the visual stimulus. We also found that a minimum of a 600 ms warning was required to produce a significant difference in the amount of time to prepare for the simulated breaking event. The results of this current study suggest that given a future automated shuttle that can detect the surrounding environment and reliably predict conditions, then there is a benefit of presenting preemptive warnings for the purpose of maintaining balance and avoiding falls.
Evaluation of Students’ Learning Through Reflection on Doing Based on Sentiment Analysis
Authors: Wu Yupeng , Ming Zhenjun , Allen Janet K. , Mistree Farrokh 
Published: November 2022

Abstract
In this paper, we address the following question:
How can instructors leverage assessment instruments used to process information gleaned from design, build, and test courses to simultaneously improve student outcomes and assess student learning well enough to improve the course in the future?
A Take-away is an unstructured text written by students in AME4163: Principles of Engineering Design offered at the University of Oklahoma, Norman, USA, to record what they understand by reflecting on authentic and immersive experiences throughout the semester. The immersive experiences include lectures, assignments, reviews, building, testing, and a post-analysis for the design of an electro-mechanical system to address a given customer need. In the context of a Take-away, a student then writes a Learning Statement that is a structured sentence written as a triple, i.e., [Experience - Learning - Value]. Between 2019–2021, we collected about 10,000 Take-aways and Learning Statements from almost 400 students.
In this paper, we address the question from the perspective of students’ feelings and use dictionary-based sentiment analysis to evaluate students’ subjective feelings toward what they are learning. Through quantitative results, we provide evidence-based guidance to instructors on improving the delivery of the course in the future. Our focus in this paper is on explaining the method using data from AME4163. The proposed method is general and can be extended for other types of courses.
Anomaly Detection of Laser Powder Bed Fusion Melt Pool Images Using Combined Unsupervised and Supervised Learning Methods
Authors: Sato Matthew M. , Wong Vivian Wen Hui , Law Kincho H. , Yeung Ho , Yang Zhuo , Lane Brandon , Witherell Paul 
Published: November 2022

Abstract
Laser Powder Bed Fusion (LPBF) is one of the most promising forms of Additive Manufacturing (AM), allowing easily customized metal manufactured parts. Industry use is currently limited due to the often unknown and unreliable part quality, which is largely caused by the complex relationships between process parameters that include laser power, laser speed, scan strategy, and other machine settings. Melt pools can be monitored with a camera aligned co-axially with the laser to monitor part quality. However, the number of images acquired can be large, exceeding hundreds of thousands for a single part. This paper investigates how the K-Means algorithm, an unsupervised machine learning method, can be used to cluster images of melt pools based on their shape, including undesirable anomalous melt pools. Another unsupervised learning method in this paper is the U-Net autoencoder, which identifies anomalous melt pools by identifying images with a large reconstruction loss. The K-Means clustering or autoencoder provides labels that can be used for training a convolutional neural network image classifier. The image classifier can then be used to identify anomalous melt pools during the LPBF process. This paper provides a first step for real-time process control of the LPBF process by demonstrating how anomalous melt pools can be automatically identified in real-time.
Considerations for the Testing and Validation of a Mobile Damping Robot for Overhead Power Lines
Authors: Choi Andrew , Kakou Paul-Camille , Barry Oumar 
Published: November 2022

Abstract
While analyses have been performed for fixed masses on power line conductors, they have not been in the context of interactions between the conductor and a mobile damping robot (MDR). There is a need to explore the potential impact of the MDR on the power line and the resulting implications for the MDR’s development as current methods of vibration control do not adequately address fatigue failure caused by wind-induced vibrations (WIV). Fixed passive vibration absorbers (FPVAs) are widely used on power lines, but they are inherently limited by their fixed nature since changes in wind conditions affect absorber performance as conductor mode shapes change. An MDR can overcome these limitations by actively transporting a passive absorber to conductor antinodes where the absorbers can most effectively remove energy from the system. In this paper, we experimentally investigate the effects of an untuned suspended mass on the conductor as an analog for the MDR, and we perform numerical analysis in MATLAB using equations of motion obtained via Hamilton’s Principle. The insights gained from this work lay a foundation to guide future experiments that will better define the operating conditions of the MDR and lead to the creation of an appropriate control framework.
Origami Claw Tessellation and Its Stacked Structure
Authors: Xing David , You Zhong 
Published: November 2022

Abstract
While many classical origami tessellations possess important kinematic properties, including flat-foldability and rigid-foldability, these patterns only possess one DOF. Stacking sheets of these origami tessellations is a fabrication technique to construct foldable meta-materials. In this paper, we present a novel origami pattern called the origami claw tessellation (OCT). This pattern not only preserves the kinematic properties found in classical origami tessellations but also possesses multiple DOFs. We show the OCT is flat-foldable and rigidly foldable through kinematic analysis. Every OCT described in this paper is an M × N grid of claw units, each of which has three DOFs. The exact number of DOFs a given M × N OCT possesses is computed using a numerical approach. When both M and N are at least two, the OCT possesses five DOFs. Each individual DOF is named and analyzed. Furthermore, copies of single-sheet OCTs can stack to form a cellular meta-material. In the simplest case, stacking a claw unit with a copy reduces the number of DOFs from three to one. Additionally, for any positive even L, the L-layer stacked M × N OCT has one DOF, showing that multiple sheets of OCTs, each with multiple DOFs, can stack to form a one DOF structure.
Programming Surfaces by Bistable Star Tiling Kirigami
Authors: Toyoka Ryuya , Tachi Tomohiro 
Published: November 2022

Abstract
Auxetic kirigami patterns have been used for fabricating given target surfaces from flat sheets. In particular, bistable kirigami patterns are useful as they keep the structure stable at the target shapes. In this paper, we propose a family of new bistable kirigami patterns that potentially resolves the limitation of existing bistable kirigami, which are (1) the small range of the scale factor that limits the target surface and (2) the asynchronous deployment with multiple locally stable states other than the target surface. The proposed patterns are obtained by adding bistability-inducing bar elements to star tiling kirigami patterns. The experiments show the improvement of synchronization of our structure. We propose an optimization-based computational design method to obtain curved surfaces by arranging the kirigami patterns and the bar elements such that each unit expands to the given scale factor. We applied this method to several surfaces and validated the physical prototypes.
A Generalized Torsional Dynamics Formulation for Multi-Mesh Gear Trains With Clearances and Torque Fluctuations
Authors: Donmez Ata , Kahraman Ahmet 
Published: November 2022

Abstract
Vibro-impacts of gears are common in various automotive geared drivetrains used in engines and transmissions, causing excessive noise issues coined as gear rattle. External torque fluctuations lead to contact loss at gear mesh interfaces of such systems to result in sequences of impacts. Drivetrain architectures used in these applications vary widely, especially in diesel engine timing gear systems, requiring specific models for each drivetrain configuration considered. This makes dynamics evaluations of different design concepts a difficult task. In this paper, a generalized unified formulation will be presented that is capable of deriving equations of motion of any drivetrain system. This generalized formulation allows a systematic and coding-friendly derivation of system matrices for rattle simulation of any multi-mesh system. The proposed methodology will be applied to example 3-axis idler and torque split configurations to demonstrate its effectiveness. A criterion will be devised to establish boundaries between no-impact and impact motions. No-rattle boundaries will be plotted on parameter maps for example 3-axis meshing configurations. A piecewise linear solution technique will be used to solve governing equations to study the coupling of vibro-impacts at gear contact interfaces. Finally, the multi-mesh discrete model of this configuration will be verified through comparisons to its deformable-body counterpart.
Designing Multistable Mechanisms Using Quadrilateral Boundary Rigid Origami
Authors: Miyajima Yuki , Lee Munkyun , Tachi Tomohiro 
Published: November 2022

Abstract
Multistable origami and its snapping behaviors between the folded states have attracted scientists’ and engineers’ attention as the building block for the design of mechanical devices and metamaterials. We propose a novel method for designing origami-based multistable structures, by which we mean (1) to obtain the prescribed overall motion and (2) to control the stiffness of snapping provided by the elastic strain. We solve this design problem by first representing the desired motion with linkage structures with quadrilateral holes, called the frames, and then filling the frames with origami modules, called quadrilateral boundary modules. By introducing an intentional incompatibility between the motions of the frames and the modules, we design the snapping behavior that follows the linkage motion. We provide the representation model to evaluate the incompatibility and propose an optimization-based framework for the design. We also validate our design through bar-and-hinge analysis and experiments using physical prototypes.