bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of Sensor Failure on Dynamometry Calibration
Authors: Vlajic Nicholas , Jonson Michael , Guers Manton 
Published: February 2021

Abstract
Dynamometers are used to measure integrated fluid dynamic loads such as thrust, torque or side forces. To resolve all of three force and three moment components, multiple embedded force gages are often used. Due to arrangement, static loads, and redundancy, the number of sensor channels can exceed the six degrees of freedom needed to resolve the generalized rigid body forces. This paper considers modeling of the force gages as simple springs to develop an elastic model of the dynamometer. The method was applied to a dynamometer consisting of six three-component force gages arranged in an axisymmetric ring. A calibration matrix based on the elastic model with individual force gage sensitivities was shown to match a full calibration matrix where properly summed force gage voltages were obtained under global load application. The elastic model was then extended to consider calibration matrices where sensors were assumed to fail. In this scenario, several virtual loads were applied to the dynamometer and the calibration matrix was obtained by minimizing the least square error. It was found that nearly half of the sensors could be lost and still a virtual calibration could be applied to the measurements. Extending the least square idea, an actual in-situ calibration matrix was formed by striking the dynamometer with a diverse set of instrumented hammer strikes. This calibration matrix also agreed with the other calibrations at frequencies below where system dynamics become important.
Velocity Frequency Analysis for a Transverse Half-Car Model With Third Damper Using Bond Graph Approach
Authors: Darius Jared , Medina Hector 
Published: February 2021

Abstract
We present a bond graph analysis of a three-damper suspension system in a transverse half-car model. This is compared against the conventional two-damper system used in most commercial and racing vehicles. The transverse third damper system pioneered by the Koenigsegg Triplex suspension system is an innovative design said to improve straight-line tire contact during single-sided disturbance and help mitigate the adverse effects of squat and dive, while not inhibiting the function of the anti-roll bar’s lateral load transfer in cornering capability. No published literature exists exploring a transverse half-car model with effects of a third damper. We focused specifically on mathematical modeling of energy element relationships exploring vehicle dynamics frequency response behavior compared between transverse half-car models with and without the third damper. Calculated transfer functions explore first-order time derivative relationships of wheel-mass velocity to the harmonic input velocity of the road surface. The mathematical model demonstrated some ranges of resonance within typical driving and racing frequencies. Implementing the model to a Formula SAE race car, we explored the effects of manipulating spring stiffness, anti-roll bar stiffness, damping ratio, and mass in both two- and three-damper systems. Ultimately, it was observed that the addition of the third damper resulted in objective improvements in vehicle dynamics, shown by a reduction in amplitude ratio of both the left and right wheels compared to a conventional system. Interestingly, the left wheel (input side) experienced a greater reduction in amplitude ratio when it was hypothesized that the right wheel would be more affected.
Full Steam Ahead: Hands-on Elementary Education and Persistence During COVID-19
Authors: Das Madhurima 
Published: February 2021

Abstract
It is well recognized that the world needs to develop interdisciplinary problem solvers and creative thinkers to address the problems of the future. Training in the fields of Science, Technology, Engineering, Art, and Math (STEAM) is essential for understanding the complexity of the world around us and for identifying and tackling critical technical and social issues. To that end, many programs have been launched all around the world to expose students to STEAM fields and to encourage them to pursue STEAM careers. Hands-on, project-based learning has been shown to get more students engaged with STEAM and help them learn key skills for the future. However, most STEAM education programs target students in upper-middle or high school. If students are nurtured at earlier ages to love thinking critically, solving problems, and building, they are more likely to pursue STEAM fields.
This paper describes the implementation of project-based STEAM curriculum with elementary school students from ages 6–13. It includes a detailed discussion of curriculum design, case studies of specific student work, subjective analysis of engagement level with various projects, and discussion of lessons learned. The paper also discusses how the makerspace environment where the students execute their projects has been set up to be accessible for students in this age range.
Additionally, the paper describes how a hands-on STEAM curriculum that traditionally relies on in-person feedback, materials, and access to peers as teammates can be maintained while having students learning remotely. Educational techniques for hands-on learning while physical distancing due to the COVID-19 pandemic are discussed.
Nonlinear Dynamics of Human Aortas for Viscoelastic Mechanical Characterization
Authors: Amabili Marco , Balasubramanian Prabakaran , Bozzo Isabella , Breslavsky Ivan D. , Ferrari Giovanni , Franchini Giulio 
Published: February 2021

Abstract
The results of this work present eleven human thoracic aortas tested on a mock circulatory loop (MCL) that was developed to simulate physiological pulsatile flow conditions. Results showed cyclic axisymmetric diameter changes, which were compatible with in-vivo cyclic diameter changes at resting heart rate. The dynamic stiffness increased with age, but the cyclic axisymmetric diameter variation decreased with age when at a resting pulse rate. The energy dissipation was also noted to decrease with increased age. The synergistic effects of the fluid-structure interaction and the viscoelasticity led to larger damping at higher pulse rates. The projected outcome of this work is creating innovative biomaterials that better reproduce the aortic dynamic behavior. The findings complement expanding avenues in advanced materials, with the aim of creating improved and mechanically compatible cardiovascular devices, like grafts and stents.
Thermo-Oxidation Analysis of Structural Adhesives: An Experimental Study
Authors: Alazhary Sharif , Mohammadi Hamid , Dargazany Roozbeh 
Published: February 2021

Abstract
Cross-linked polymers play an important role in structural applications as adhesives. In this article, we performed an experimental study to understand the effects of high temperature i.e. thermo-oxidative aging on the mechanical behavior of polymers. Subsequently, the constitutive behavior, i.e. stress-strain relation of these adhesives before and after the accelerated aging tests were studied on samples aged at different temperature and different time durations at zero humidity. The aging conditions and periods selected for the tests have been specifically designed to simulate the effects of aging under the working conditions that the materials will be subjected to in their standard applications. The focus of this study is on the investigation of the effects of aging on the polymeric adhesives used in automotive applications. Consequently, four different polymeric adhesives (one silicone-based, two polyurethane-based, and one acrylic type), which are being used extensively in these applications, have been chosen. The quasi-static tensile loading was used on these four adhesives and the changes in the constitutive behavior were measured. The failure tensile tests as well as the cyclic tensile tests were performed in our lab using a Test-Resources tensile testing machine. The temperatures that were used in this work are 60, 80 and 95°C for varying aging periods of 24hrs, 240hrs, and 720hrs. Then, all the data was collected and consequently analyzed, and the resulting behavior was compared to that of the unaged material, showing varying results depending on the material, temperature, and aging period. Different behaviors have been observed after aging. The polymers’ behavior was expanding from no effect to significant damage caused by aging conditions. This work provides the core understanding required for modeling the material behavior during aging and lays down the groundwork for further data-infused model-free approaches.
Influence of Composite Polymer Coatings on the Insertion Force of Needle-Like Structure in Soft Materials
Authors: Patel Kavi I. , Zhu Long , Reddy Gidde Sai Teja , Ren Fei , Hutapea Parsaoran 
Published: February 2021

Abstract
This study is aimed to evaluate the effects of coated surgical needles with composite polymers such as polydopamine (PDA), polytetrafluoroethylene (PTFE), and carbon. The coated needle’s lubrication properties were measured using 3 DOF force sensors and 3D robot system by the repetitive insertion in soft tissue materials. Needle durability is a measure of needle sharpness after repeated passage through high stiffness tissue materials. The composite coatings were shown to reduce the insertion force by ∼49% and retraction forces by ∼46% when tested using a bovine kidney. The surface roughness and the lateral friction force of the needle are measured using the Atomic Force Microscope (AFM). The adhesion energy of the different coating on the needle will be measured using a nano-scratch method.
Quantifying the Effects of Convective Heat Transfer on Photovoltaic Performance and Optimal Tilt Angle
Authors: Ghabuzyan Levon , Kuo Jim , Baldus-Jeursen Christopher 
Published: February 2021

Abstract
Electrical performance of photovoltaic (PV) cells are affected by their operating temperatures, which lead to changes in the performance of the PV panel. The performance and efficiency of a PV system is dependent upon many factors, such as its angle of incidence, accumulation of dust, speed and direction of natural winds. Particularly, angle of incidence between solar rays and PV modules is the most important. This paper will focus on developing a numerical tool for predicting the optimal tilt angle, based on wind flow over PV panel in a fixed tilt array, in order to observe the effects on performance. A 1.651 m long by 0.991 m wide solar PV panel is used in the analysis. The panel is mounted on top of a tall building and the tilt angle is fixed at one angle. This paper will observe how the PV panel is affected by wind flow and how the optimal tilt angle will change, and if it is necessary to account for convection. Increasing convective heat transfer has the potential to reduce the operating temperatures of photovoltaic solar panels thus increasing their efficiency and producing more power. This relationship was used in a numerical tool to predict the performance of the panel at different tilt angles and different wind speeds. The results show that wind speed and direction do affect power output and that designers should account for convective effects when designing positioning and orientation of solar panels.
A Long-Distance/Online Teaching Model With Video Technology for Engineering Courses Suitable for Emergency Situations
Authors: Rodríguez-Paz Miguel X. , González-Mendivil Jorge A. , Zamora-Hernandez Israel 
Published: February 2021

Abstract
In this paper we present the implementation of a model involving real-time online education sessions for the continuation of a semester in emergency situations when the university has to stop activities. This model has been used during the strong Earthquakes in Central Mexico in September 2017 and during the most recent global situation due to the coronavirus emergency.
Teaching of Engineering courses usually involves the combination of lectures, tutorials, problem solving sessions and mid-term exams. In emergency situations when the activities at the university are not possible, other models have to be implemented, usually within a short period of time. In this paper, a model involving the use of video conferencing software, namely zoom, the use of video repositories and the use of digital social media is presented as a successful model for the continuing teaching of courses of Engineering Mechanics. Results show a good acceptance by students and some suggestions given by the students in order to make this model more attractive are also presented. These findings can be applied in the future in the design of schemes for teaching or continuation of a term in higher education when the university faces an emergency that requires activities to be interrupted oncampus.
As conclusions the authors present a series of recommendations for teachers or professors interested in applying this model or in designing new schemes for teaching online when the university has to be closed.
Effect of Adding Graphene Nano-Platelets With Surfactants on Bio-Based PCM Characteristics and its Cooling Performance
Authors: Sheikh Yahya , Gadalla Mohamed , Umair Muhammed , Mehaisi Elmehaisi , Azmeer Ahmed 
Published: February 2021

Abstract
Phase change materials (PCM) are materials that absorb/release large amounts of thermal energy at constant temperatures during phase change. Consequently, PCMs could be effective when electronic cooling systems such as heat sinks and heat pipes are considered. In the selection of PCMs for cooling systems, bio-based PCMs are more effective when compared to inorganic PCM. However, bio-based PCMs have poor thermal conductivity and therefore suffer from poor heat transfer characteristics. The diffusion of certain additives within the PCM has proven successful in the enhancement of heat transfer during the cooling process. Graphene Nanoplatelets (GNPs) presents itself as one such additive. Using PureTemp PCM as a heat sink for an electric heater, this paper experimentally investigates the cooling performance of the heat sink when GnPs and various surfactants such as, SDS, SDBS and SSL, are added to the bio-based PCM. Finally, results indicate that the addition of GnPs increased the time taken for the heater to reach a reference temperature of 43 °C by nearly 12% when compared to PurePCM heat sink, indicating an improved cooling performance of the PCM heat sink when GnP’s were added. Furthermore, the experiment indicated that SSL surfactant showed a 9% increase in time taken to reach the reference temperature when compared to other surfactants. SDS surfactant indicated the highest increase in thermal conductivity when compared to other surfactants as it reported the highest increase of 147% when compared with the thermal conductivity of PurePCM.
Crystalline Phase Change due to High Speed Impact on A36 Steel
Authors: Slewa Muna 
Published: February 2021

Abstract
The well-known industrial standard called A36 alloy steel is an iron-based alloy that has many applications due to its ability to be easily machined and welded. The alloy has less than 0.3% carbon by weight and is therefore considered a low carbon alloy. Because of this low carbon content, the alloy is useful as a general-purpose steel. It is altogether strong, tough, ductile, weldable, and formable. It is used in the construction of bridges, buildings, automobiles, and heavy equipment as well as in the construction industry. A36 steel also contains small amounts of other elements including manganese, sulfur, phosphorus, and silicon. These elements are added to give the steel alloy desired mechanical and chemical properties. The A36 steel alloy gets the number 36 in its name because of its yield strength. The steel, in most to all configurations, will have a yield strength of a minimum of 36,000 pounds per square inch. This shows high ductility in the material.
The physical characteristics and molecular structure of A36 steel are also well known. However, there is little known about the effect of high-velocity impact on the crystalline structure and material phase of this metal alloy. Sections of approximately 90 × 90 square microns were cut off the test samples, keeping with the required standards for surface finish. These surfaces were examined and analyzed after impact. The surface sections were selected from a range of areas including those immediately under the impact crater to locations not physically affected by the impact. Three different impact speeds were applied, and the prepared samples were examined. An EBSD (Electron Backscatter Diffraction) imaging microscope is used to examine the crystalline structure of the test sample post-impact.
Most metals crystallize in one of three prevalent structures: body-centered cubic (BCC), hexagonal close-packed (HCP), or face-centered cubic (FCC). Since these crystalline structures are the most expected lattice formations, the samples are examined post impact for changes in the allocation of molecular structure. The results were then tabulated according to the regions relative to the impact crater. In previous research, results show that post-impact inspection of HCP phase change, in iron specifically, is completely and rapidly reversible during impact. However, in this study, traces of HCP were found at some locations in all stages of post-impact. This study also found that the BCC crystalline structure remained the dominant phase structure after impact. This is true with all test samples and all levels of shock loading.
Modelling and Performance Analysis of Different Types of Li-Ion Battery
Authors: Durganjali C. Santhi , Raghavan Harini , Radhika Sudha 
Published: February 2021

Abstract
Lithium ion batteries are at present, the most widely used battery technology in the world. Every battery’s performance is characterized by certain parameters like the State of Charge, and Depth of Discharge, C-rate etc. To explore the possibility of more efficient types of Li-ion batteries for more applications a wide demand in identifying, modeling and testing of different possible combinations of electrode materials and electrolytes of Li-ion batteries arose. Taking this demand into consideration authors of this paper focus on the modeling and simulation of a wide variety of possible combinations of Li-ion battery in a 2-dimensional model. In addition to that, a thermal model of a cylindrical lithium ion battery was built in 3-dimensions and was validated with experimental data. The simulations were carried out on COMSOL:Multiphysics.
Application of Deep Neural Network in the Design of Microresonators Subject to Microfabrication Constraints
Authors: Alaie Seyedhamidreza 
Published: February 2021

Abstract
Deep Neural Networks (DNNs) have transformed various fields, yet their application in design of microsystem has been limited. Here, we demonstrate a framework for application of adversarial generative networks in design of microresonators targeting for operation in MHz frequencies. The topology of the microresonators are constrained based on the critical dimension common in the photolithography process. The design-space includes a free standing window of Si film on an SOI wafer that is supported on its four sides. The film is etched through a mask with an arbitrary 2D layout. We employ DNNs in finding 2D layouts that result in a membrane with desirable natural frequencies. For this purpose, deep generative networks (generators) and deep neural networks (discriminators) are employed. Two datasets representing desirable and undesirable layouts are created using finite element analysis. Subsequently, the discriminator is trained to classify desirable and undesirable layouts as well as those generated by the generator. Simultaneously, the generator is trained to sample layouts that are more likely to be classified as desirable by the discriminator. The results show that this framework is capable of producing designs with desirable vibrational features, encouraging further research in this topic.
A New Kinematic Error Modelling and Identification Method of the Parallel Manipulator
Authors: Li Weitao , Wang Liping 
Published: February 2021

Abstract
Parallel manipulators have broad application prospects on hybrid machine tools. Kinematic error modelling and identification are two key processes to improve the accuracy of parallel manipulators. The traditional kinematic error modelling method adopts the partial differentiation of the ideal kinematic model. However, the partial differentiation method is pure mathematical calculation, which ignores physical meaning of error terms corresponding to each link. In the process of error identification, the Jacobian matrix obtained from the partial differentiation method is usually ill-conditioned, which leads to non-convergence of the identification process. In order to solve the above problems, this paper proposes a new kinematic error modelling method and an error identification model. Firstly, the basic error terms for single link are analyzed. Based on basic error terms, the kinematic error model is established by using the practical connection point of two adjacent links. Then, a new error identification model is derived from the kinematic error model. Finally, as a study case, a 3-DOF parallel tool head is used to verify the correctness of the proposed method. The numerical results show that the proposed method is effective and the accuracy of the 3-DOF parallel tool head improves significantly after compensation of error terms.
Wide Bandwidth Piezoelectric Energy Harvester With Transverse Movable Mass
Authors: Rodriguez Luis A. , Jackson Nathan 
Published: February 2021

Abstract
High Q-Factor vibrational energy harvesters are ideal as they maximize power generation, but a narrow bandwidth limits the potential use in most commercial applications, and it is a major challenge that has not been resolved. Numerous designs have been investigated to solve this challenge but most of the attempts are based on frequency sweeping mechanism or require complex design/fabrication which are not practical especially for MEMS devices. This paper reports for the first time a transverse vertical moving mass inside the proof mass as a method to widen the bandwidth which is independent of frequency sweeping. The out-of-plane movable mass is achieved by fabricating a vertical cavity in the proof mass and partially filling the cavity with metallic spheres. Ultra-wide bandwidth was achieved for low (0.5g) and high (1g) accelerations with an increase in bandwidth from 3.9 Hz (control) to 56 Hz (movable mass). This transverse method of widening the bandwidth is potentially scalable to MEMS devices.