bluuebunny/crossref_metadata_2025_split huggingface dataset:
Compressive Stress Relaxation (CSR) Testing of Elastomers
Authors: Menon Dilip , Michael Robert J. , Gee David 
Published: January 2022

Abstract
This paper presents Compressive Stress Relaxation (CSR) results for various elastomer samples to ascertain their performance in sealing applications. The paper presents results of percent retained sealing force (%RSF) behavior and its relationship with compression set and hardness. Materials studied are used in critical piping and medical seal applications. CSR methodology is used to benchmark various materials in terms of sealing performance. Potential problems with the current standard of testing have also been identified that can affect the resolution and variability of the test. The paper details all the steps involved to perform accurate CSR testing and discusses advantages and disadvantages CSR testing might have over conventional tests used to verify seal performance such as compression set. This is only an introductory study and requires further tests with the same elastomers subjected to other process conditions, such as heat aging are also studied to understand how they affect %RSF. This can also be expanded to other materials to build a database of standard %RSF behavior under identical conditions.
Introducing Mechanical Engineering Students to Online Robotics Laboratories
Authors: Danesi Ruiz Juliana , Deierling Phillip E. 
Published: January 2022

Abstract
Due to Covid-19, in-person robotics labs held in previous semesters were not possible. This paper explores a well-established method to give the students an exceptional learning experience in a robotics class. By surveying students, data was gathered to account for students’ perception when designing the laboratories and lab manuals. In addition, to find an adequate program for the labs, different software was researched and tested. The main factors used to select a software were intuitiveness, cost, online resources, operating system compatibility, Python programming, and software usage. It is concluded that the RoboDK software is the most suitable software for the laboratories, and updated manuals needed to be designed for the Spring 2021 class. Last semester, Spring 2021, another survey was conducted to get students’ feedback on the new lab system. With the additional data, further research may be conducted to refine the laboratories’ assignments and manuals. This paper’s main contribution is to use and analyze RoboDK for online robotics laboratories. Therefore, through this research, a new method was presented that gave students hands-on experience on online laboratories.
On Periodic Firing Activities of a Hindmarsh-Rose Neuron Model With External Periodic Stimulus
Authors: Xu Yeyin , Feng Peihua 
Published: January 2022

Abstract
In the paper, periodic firing phenomenon of a Hindmarsh-Rose neuron model is explored by the discrete mapping method. The continuous nonlinear differential equations are discretized to form implicit mappings for periodic firing motions of neurons. Periodic firing and period doubling firing activities are investigated by changing the external excitation frequency. The influence of bifurcations on the periodic firing patterns is discussed. Time series membrane potential and adaptive current of such a modified Hindmarsh-Rose neuron model are presented. Fast-varying spikes and slow-varying zones of the neuron firing waves are revealed for a better understanding of the neural firing phenomenon. The nonlinear complexity of the periodic excited Hindmarsh-Rose neuron model is released.
Effects of Convection on Experimental Investigation of Heat Generation During Plastic Deformation
Authors: Hodges Wyatt , Phinney Leslie M. , Lester Brian , Talamini Brandon , Jones Amanda 
Published: January 2022

Abstract
In order to predict material failure accurately, it is critical to have knowledge of deformation physics. Uniquely challenging is determination of the conversion coefficient of plastic work into thermal energy. Here, we examine the heat transfer problem associated with the experimental determination of β in copper and stainless steel. A numerical model of the tensile test sample is used to estimate temperature rises across the mechanical test sample at a variety of convection coefficients, as well as to estimate heat losses to the chamber by conduction and convection. This analysis is performed for stainless steel and copper at multiple environmental conditions. These results are used to examine the relative importance of convection and conduction as heat transfer pathways. The model is additionally used to perform sensitivity analysis on the parameters that will ultimately determine β. These results underscore the importance of accurate determination of convection coefficients and will be used to inform future design of samples and experiments. Finally, an estimation of convection coefficient for an example mechanical test chamber is detailed as a point of reference for the modeling results.
Creep-Fatigue Damage of Heat-Resistant Alloys Caused by the Local Lattice Mismatch-Induced Acceleration of the Generation and Accumulation of Dislocations and Vacancies
Authors: Luo Yifan , Tezuka Shogo , Nakayama Koki , Nakayama Ayumi , Suzuki Ken , Miura Hideo 
Published: January 2022

Abstract
Degradation mechanism of the strength of a grain boundary in Ni-base superalloy under creep-fatigue loading at elevated temperature was investigated by using the modified Arrhenius equation, which explained the stress-induced acceleration of the local generation and diffusion of dislocations and vacancies. EBSD analysis confirmed that dislocations and vacancies started to generate and accumulate around grain boundaries and the interface between precipitates and matrix in grains. The generation and accumulation were accelerated around the interfaces with large difference in the lattice constant between the nearby crystallographic phases and grains. The activation energies of the diffusion of dislocations and vacancies measured under the harsh condition was much lower than those measured under the thermodynamically stable conditions. It was confirmed that there are two main acceleration mechanisms of the degradation of the crystallinity and strength of grain boundaries under a tensile stress at elevated temperatures: the acceleration of the generation and diffusion of dislocations and the acceleration of accumulation of voids due to the outward diffusion of component atoms from the grain boundaries. These phenomena were explained by the modified Arrhenius equations in which the effective activation energies were changed by the summation of the applied nominal stress and the localized internal stress around various interfaces quantitatively.
Visualizing Fundamental Concepts Taught in Helicopter Dynamics Course Using Matlab Simscape GUI Program
Authors: Esquen Andrea Contreras , Martinez Jose Bonilla , Pena Paul , Khalid Adeel , Tekes Ayse 
Published: January 2022

Abstract
Students taking traditional undergraduate level engineering courses not only struggle with highly complex concepts but also struggle in linking the physical meaning of the derived mathematical equations. In this study, we developed a standalone and user-friendly Matlab Simscape Graphical User Interface (GUI) program to visualize the concepts presented in the undergraduate level helicopter dynamics course. The developed GUI program enables students to change the parameters of the blade including the rotor radius, blade chord, type of airfoil, material properties, the weight of the aircraft and analyze the effect of the parameter on the performance of the helicopter rotor. The program uses motion dynamics to simulate the blade movement in hover and forward flight. The Simspace GUI program is composed of four modules starting with a simplistic beam model. In the first module, the blade is considered as a simple cantilever beam where an input point load is applied at the tip of the blade either vertically down or at an angle. In the second module, the force is replaced by a radially distributed load that simulates lift distribution along the span of the blade. In the third module, the distributed load is applied to various types of airfoils ranging from symmetrical NACA airfoil to supercritical airfoils. In the fourth model, the sectional velocities vary as a function of azimuth, and the forward-moving rotor is simulated.
Mechanisms Design for the Hinge & Battery Lifetime Tests for a Prototype
Authors: Deemyad Taher , Akula Vincent , Sebastian Anish 
Published: January 2022

Abstract
In this paper, we design application specific mechanisms and control systems to test and deduce the lifetime of custom-designed hinges and batteries. These hinges and batteries are critical components of prototypes for a patented smart toilet seat. The work done here was used to improve the existing design and to identify a replacement cycle for these seat components. The target audience for this smart seat is airports and venues with large crowds. The smart seat has a cleaning solution that is contained within the seat in a cartridge, which can be easily replaced by facilities. The seat includes a motion sensor, battery, and slow hinges inside of it. This seat employs a slow hinge which reduces the impact of repetitive opening and closing of the seat. The hinge lifetime was tested and to this end a specific mechanism was designed. In this test, time required for opening seat, closing seat, and total number of opening/closing cycles the seat underwent was recorded. Also, in another experiment, the lifetime of the battery powering the pumping mechanism was tested until failure, where the battery voltage fell below a specific value and could no longer pump the cleaning solution out of the ports. Finally, the results for each experiment were compared for different samples and analyzed.
Design of an Affordable Prosthetic Arm Equipped With Deep Learning Vision-Based Manipulation
Authors: Imran Alishba , Escobar William , Barez Fred 
Published: January 2022

Abstract
Many amputees throughout the world are left with limited options to personally own a prosthetic arm due to the expensive cost, mechanical system complexity, and lack of availability. The three main control methods of prosthetic hands are: (1) body-powered control, (2) extrinsic mechanical control, and (3) myoelectric control. These methods can perform well under a controlled situation but will often break down in clinical and everyday use due to poor robustness, weak adaptability, long-term training, and heavy mental burden during use.
This paper lays the complete outline of the design process of an affordable and easily accessible novel prosthetic arm that reduces the cost of prosthetics from $10,000 to $700 on average. The 3D printed prosthetic arm is equipped with a depth camera and closed-loop off-policy deep learning algorithm to help form grasps to the object in view. Current work in reinforcement learning masters only individual skills and is heavily focused on parallel jaw grippers for in-hand manipulation. In order to create generalization which better performs real-world manipulation, the focus is specifically on using the general framework of Markov Decision Process (MDP) through scalable learning with off-policy algorithms such as deep deterministic policy gradient (DDPG) and to study this question in the context of grasping a prosthetic arm. We were able to achieve a 78% grasp success rate on previously unseen objects and generalize across multiple objects for manipulation tasks.
Parameter Optimization of a New Battery Model
Authors: Rose Cameron , Pence Ben 
Published: January 2022

Abstract
The lithium-ion battery (LiB) has become increasingly popular in electric vehicles (EVs), laptops, phones and many other devices that people use every day. It is popular due to its high energy density, low cost, lack of memory effect (typical of older battery types), longer life cycle (more full cycles till battery dies), and more. Because of its common use in everyday applications, knowing the state of charge (SOC) of a lithium-ion battery becomes an important problem to solve.
The first goal of this work was to develop and present a new battery model derived from fundamental principles of electrochemistry, Fick’s first law of diffusion, and a mass balance of lithium-ions between the anode and cathode. A voltage equation was developed based on the the open circuit voltage, the Nernst equation, and Ohm’s law. The battery model aims to accurately track the movement of lithium ions without being too computationally demanding, while the voltage equation relates the output of the model to the voltage of the cell. These equations are coupled and solved simultaneously. The SOC of the battery could then be determined based on the mass of lithium in the anode.
The second goal of this work was to optimize the parameters of the battery model to make it match experimental data. A cost function was defined and a genetic algorithm was implemented to minimize the cost function by altering the model parameters. The genetic algorithm successfully reduced the cost function. The model matched the experimental data and is therefore ready for commercial application.
Design, Prototyping, and Testing of a Robotic Prosthetic Leg Preliminary Results
Authors: Davidson Michael , Daher Noha , Fryer Thomas , Schaepper Johannes , Tran Duc 
Published: January 2022

Abstract
We report on our design and initial evaluation of a prototype robotic prosthetic leg (RPL) with a powered non-backdrivable knee and a hydro-pneumatic passive-resistive ankle. Our design was intended to increase health providers’ opportunities when offering their patients greater options, expanding the accessibility of advanced technology to those with lower functional levels of ambulation while decreasing the overall costs of care. The purpose of this biomedical device was to improve stance stability, increase balance confidence, and through powered-knee extension, reduce the contralateral limb’s kinetic stresses in gait, sitting, and standing. This device was designed to provide K2 and above ambulators a more adaptive, safe, and enhanced lower limb prosthesis. The prototype was assessed on a healthy subject while performing multiple 10-meter walk tests (10MWT) and six-minute walk tests (6MWT) on level-ground, inclines, and declines. We report walking velocity, the frequency of steps, cadence, falls, stumbles, toe-drags, battery consumption, and estimated torque of the knee actuator. We found the device safe on an able-bodied subject and feasible for future use on persons with limb loss.
Project Based Course Enabled Nanotechnology Education for Senior Level Undergraduate and Graduate Students
Authors: Dang Hongmei , Tyagi Pawan , Ososanya Esther , Klein Kate 
Published: January 2022

Abstract
National Science Foundation funding was obtained to nucleate nanotechnology curriculum and start a senior-level nanotechnology course cross-listed in the Mechanical Engineering and Electrical Engineering department. The key components are implementation of lectures integrated with hands-on laboratory experience, research seminar and evaluation. Laboratory projects of nanofabrication include metal-oxide-semiconductor capacitor and nano-structured solar cell for undergraduate and graduate students respectively. The assessment of course materials and master’s understanding was evaluated by surveys and direct observations of student performance. In spring 2020, statistical data from survey demonstrated that graduate students responded overall high rate for all of the course materials and undergraduate students gave high rate for majority of course materials except thermal evaporation fabrication project. A significant standard deviation for rating of thermal evaporation fabrication process indicated that practical engineering projects are challenging for some undergraduate students.
Structural Optimization for Segment-based Design of Part Candidates For Incremental Manufacturing
Authors: Redeker Julian , Vietor Thomas 
Published: January 2022

Abstract
The Incremental Manufacturing approach is based on a production concept, where products are assembled from mass-produced parts and finalized by additive and subtractive manufacturing steps. This approach promises economic variant production but also leads to increased complexity in product design and process planning due to the enhanced degree of freedom. Therefore, new methods and tools to support product development in the early design stages are investigated to exploit the production concept’s full potential.
In the context of redesigning parts for Incremental Manufacturing, a graph-based approach was introduced to support the design engineer in generating part concepts based on automated CAD model segmentation of a reference part. In this process, the extracted part segments are concretized based on algorithms, for example, by assigning predestined manufacturing processes, suitable pre-produced parts, materials, and joining technologies. For the concretization and early potential evaluation of the part candidate’s functionality in terms of mechanical performance, an optimization approach is introduced in this paper. This approach enables a combined structural optimization of part candidates with respect to the topology of additively manufactured areas and the shape of the pre-produced parts.
Pitch Angle & Decalage Effect in Biplane Blade Design for Wind Turbines
Authors: Atique Md Saifuddin Ahmed , Song Xueling , Yang Cai Xia 
Published: January 2022

Abstract
To reduce the environmental pollution and introduce new form of energy source, the popularity of harvesting energy from wind is increasing day by day. Wind turbines blades are growing longer, as increasing blade length is one of the best ways to produce more wind energy per turbine. However, longer blades require thicker root at the inboard section to counteract the bending load and this thicker root at the inboard section of the large wind turbine blades lower the blades aerodynamic efficiency. This loss of aerodynamic efficiency prevents these longer wind turbine blades from being fully effective as the cost to benefit ratio increases and less power is generated than the optimal value. Additionally, these long blades use a large amount of material. Longer blades require more support to remain structurally sound, which causes a large increase in mass. This material is hard to break down and decompose, causing them to take up a large amount of space in landfills when the blades are unserviceable or replaced because of damage and stress. To overcome this drawback and maximize the harvested energy from the wind, a novel “Biplane” shape wind turbine blade is proposed by the researchers which replaced the monoplane inboard section of the traditional wind turbine blades with the biplane inboard section. This new concept allows to design and manufacture longer wind turbine blade without any loose in aerodynamic efficiency and structural integrity. Biplane wind turbine blades have shown very interesting and promising characteristics in terms of both aerodynamics and structural performance. This new type of wind turbine blade can ensure more power, better aerodynamics efficiency, structural integrity along with lower manufacturing and transportation cost. Previous research conducted found the significant effect of gap and stagger in the aerodynamic performance of biplane blades. However, another very important parameter “pitch angle & decalage” that can improve the aerodynamic performance of biplane wind turbine blades remains unchecked. Keeping that in mind, the current research performed a detailed computational fluid dynamic (CFD) based analysis to find out the pitch angle & decalage effect in biplane wind turbine blade design. Our current research revealed that, apart from the contribution of gap and stagger, the effect of pitch angle & decalage can be significant. At a 6° angle of attack, with both top and bottom blade aerofoil pitch angle setup at positive (+ve) 3° which means decalage is 0°, can improve the lift coefficient (Cl) and the lift to drag ratio (Cl/Cd) or aerodynamics efficiency raised around 48% higher while gap to chord ratio (g/c) and stagger to chord ratio (s/c) were kept 0.5 and 0.25 respectively obtained from the previous state of art.
Dependencies of Parallel Sparse Iterative Linear Solver Methods on Matrix Conditioning on Unstructured Finite Element Meshes
Authors: Lu Qiyue , Koric Seid 
Published: January 2022

Abstract
Iterative methods are widely used for solving sparse linear systems of equations and eigenvalue problems. Their performances are relevant to the conditioning of the linear systems. This work explores factors which affects the conditioning of the discretized system, including material heterogeneity, different constitutive characteristics and element sizes, and reveals the dependencies among solvers performance and the conditioning of linear systems. Results show that multiple materials can alter the eigenvalue distributions significantly, while lowering Young’s modulus results in higher condition numbers but has less effects on the spectral scope, additionally, there is a approximately reciprocal square linear relation between element size and condition numbers. These entangled effects along with the chosen pre-conditioners render that there is no simple monotonic increasing dependency among condition numbers and solving time, except with specific conditions. It is hoped that this work will provide more understanding of the iterative sparse linear solver behavior used in similar structural problems.
The Evaluation of Tribological Performance of Laser Micro-Texturing Ti6Al4V Under Lubrication With Protic Ionic Liquid
Authors: Pang Junru , Guo Hong , Vázquez Martínez Juan Manuel , Salguero Jorge , Iglesias Victoria Patricia 
Published: January 2022

Abstract
Laser micro-texturing treatment has been proved as an efficient way to improve tribological properties of metal alloys. Meanwhile, ionic liquids also show great potential as novel lubricant additives to increase the durability of contacting components and decrease the energy loss during tribological process. This study investigated the influence of the laser micro texturing surfaces on the tribological performance of titanium alloy Ti6Al4V under different lubricant conditions. In this research, two sets of dimple-textured surfaces created by different laser parameters, energy density and area density, were fabricated on Ti6Al4V. Polyalphaolefin (PAO) 40 and 1 wt.% 2-hydroxyethylammonium 2-ethylhexanoate (Eet) used as additive to PAO 40 were designed as lubricants during the sliding tests. First, the geometrical properties of laser micro-textures on the surfaces were characterized. The wetting behaviors of different lubricants on textured surfaces were then examined based on contact angle measurement. All the frictional tests were carried out on the ball-on-flat reciprocating tribometer under the same working conditions. Lastly, the surface morphology of the wear tracks on Ti6Al4V and tungsten carbide balls and their wear mechanisms were evaluated by using the optical microscope, scanning electron microscope, and energy-dispersive X-ray spectroscopy. The results exhibit the laser micro-textures have a positive effect on improving the tribological performance of Ti6Al4V. Meanwhile, the use of Eet as the lubricant additive to PAO 40 can facilitate the formation of the tribo-layer, which enhances the tribological behavior of laser micro-texturing Ti6Al4V surfaces.