bluuebunny/crossref_metadata_2025_split huggingface dataset:
Internal Resistance Based Assessment Model for the Degradation of Li-Ion Battery Pack
Authors: Wulandari Iffandya Popy , Pan Min-Chun 
Published: February 2021

Abstract
As one pioneer means for energy storage, Li-ion battery packs have a complex and critical issue about degradation monitoring and remaining useful life estimation. It induces challenges on condition characterization of Li-ion battery packs such as internal resistance (IR). The IR is an essential parameter of a Li-ion battery pack, relating to the energy efficiency, power performance, degradation, and physical life of the li-ion battery pack. This study aims to obtain reliable IR through applying an evaluation test that acquires data such as voltage, current, and temperature provided by the battery management system (BMS). Additionally, this paper proposes an approach to predict the degradation of Li-ion battery pack using support vector regression (SVR) with RBF kernel. The modeling approach using the relationship between internal resistance, different SOC levels 20%–100%, and cycle at the beginning of life 1 cycle until cycle 500. The data-driven method is used here to achieve battery life prediction.based on internal resistance behavior in every period using supervised machine learning, SVR. Our experiment result shows that the internal resistance was increasing non-linear, approximately 0.24%, and it happened if the cycle rise until 500 cycles. Besides, using SVR algorithm, the quality of the fitting was evaluated using coefficient determination R2, and the score is 0.96. In the proposed modeling process of the battery pack, the value of MSE is 0.000035.
Feature Selection for Audio-Based Fault Detection in Pumps
Authors: Adegboye Victor O. , Rife Jason H. 
Published: February 2021

Abstract
Whilst extensive work has been done on fault detection in bearings using sound, very little has been accomplished with other machine components and machinery partly due to the scarcity of datasets. The recent release of the Malfunctioning Industrial Machine Investigation and Inspection (MIMII) dataset opens the opportunity for research into malfunctioning machines like pumps, fans, slide rails, and valves. In this paper, we compare common features from audio recordings to investigate which best support the classification of malfunctioning pumps. We evaluate our results using the Area Under the Curve (AUC) as a performance metric and determine that the log mel spectrum is a very useful feature, at least for this dataset, but that other features can enhance detection performance when ambient noise is present (improving AUC from 0.88 to 0.94 in one case). Also, we find that mel Frequency Cepstral Coefficients (MFCC) perform substantially poorer as features than a sampled mel spectrogram.
Material Dependent Laser-Induced Patterns for Metal-Plastic Hybrids Directly Jointed Using Injection Molding
Authors: Peng Fei , Yang Can , Li Chunbo , Yang Huan , Yin Xiao-Hong 
Published: February 2021

Abstract
In the present work, the nanosecond-pulsed laser micro machining was applied to induce surface patterns with three different metals (i.e., titanium, aluminum as well as magnesium alloys) for producing metal-plastic hybrid (MPH) joints by injection molding. Specifically, laser variables such as the scanning speed, laser frequency, and scan repetition were altered to obtain different surface patterns. The surface morphologies were observed using scanning electron microscope (SEM). It’s found from SEM observations that due to the thermal ablation of the laser, micro patterns such as grooves and protrusions exist on all metal surfaces. However, distinct morphologies can be seen for different metals, with the most variable microstructures for the titanium alloy. Moreover, the surface wettability to the distilled water for all metal surfaces was examined with a contact angle measuring instrument. It’s shown that the contact angle characterizing the surface hydrophilicity is not necessarily related to process condition but surface morphologies. The tensile tests of the injection molded MPH joints showed that the titanium alloy surfaces with bumpy morphology facilitated forming micro-scale mechanical interlocking between the metal and the plastic, leading to enhanced MPH joint strength.
Feature Extraction Based on Teager-Kaiser Energy Operation and Envelope Spectra for Fault Detection of a Reciprocating Compressor
Authors: Hou Chin-Che , Pan Min-Chun 
Published: February 2021

Abstract
In this paper, signal analysis techniques based on Teager-Kaiser energy operation and envelope spectra for fault detection of the discharge valve of a reciprocating compressor is proposed. The method can accurately identify the existing fault of vibration signal features that it simulated by the synthetic signals. A two-phase study was designed to explore the signals simulation and the experimental validation. Signals simulation, which is based on the operation of a reciprocating compressor, and experiment design, which uses three conditions. The first stage is to simulate the operation of the reciprocating compressor, which is to simulate a synthetic signal for the cycle and impact. The synthetic signal is composed of a noise, square wave, and pulse wave. In this study, the synthetic signal is signal-processed by the Teager-Kaiser energy operator and the envelope spectrum that they can effectively extract feature signal and the noise almost is eliminated. The second stage is applied to the signal processing technique proposed in the first stage. Experimental verification of experiment design by the different operating conditions of reciprocating compressor valves. Through the above analysis technology, it is proved that the synthetic signal can be eliminated the background noise to obtain the feature signal. The feasibility of the proposed approach is verified by simulation results, the experiment is to validate with the measurement signals from a six-cylinder reciprocating compressor under different valve conditions. Simulations and experimental results support the proposed technology positively.
Modeling Vapor Transport in a Hollow Fiber Membrane Humidifier Using ε-NTU Approach
Authors: Vu Hoang Nghia , Nguyen Xuan Linh , Yu Sangseok 
Published: February 2021

Abstract
In a fuel cell vehicle, the water content of the gas supply within certain ranges plays a key role in improving the performance of a proton exchange membrane. The lower limit of water content in the air supply is to avoid the problem of drying-out, while the upper prevents flooding. Water management can be accomplished by a membrane humidifier which allows water vapor to permeate the mixture from the side having the higher water concentration, moving to the other side of the membrane.
In this study, the variation in water content collected at the outlet of a membrane humidifier is investigated with a one-dimensional mass exchanger model and various operating variables. The vapor concentration of outlet flows is affected by operating temperature and relative humidity of the membrane humidifier. Relative humidity of the dry side at the point of outlet flow, to be supplied to the fuel cell module, is the key characteristic. The analogy of the effectiveness-NTU approach for heat transfer is used to analyze the characteristics of the mass exchanger. Mass flux through the membranes is estimated with an overall mass transfer coefficient which represents vapor transport characteristics moving through the membrane module. This coefficient has a similar role to the overall heat transfer coefficient in heat exchanger analysis. This parametric study is conducted to understand the effects of different variables. The Effectiveness-NTU methodology of mass transfer uses the overall mass transfer coefficient and the mass transfer rate, as evaluated experimentally. Simulink software is then employed to deliver outcomes of the model for different operating conditions.
Numerical Analysis of Machining Part Distortion in Aircraft Aluminum Structures
Authors: Ledesma-Orozco Elías , Rodríguez-Sánchez Alejandro E. 
Published: February 2021

Abstract
The inherent residual stresses in the raw materials of large monolithic structural components whereby machining procedures are needed to produce aircraft components, cause deviations, and distortions that are undesired and rise challenges for engineering design and engineering production teams of the aerospace companies. A numerical approach to address part distortion is proposed in this paper. An algorithm was developed and implemented as a finite element subroutine in the software ANSYS APDL, which uses the raw inherent residual stress parameters of the aluminum alloy and the machining locations of a structural specimen to simulate the machining distortion phenomenon in aircraft aluminum structures. This algorithm uses as inputs the finite element mesh of a component, the coefficients of residual stresses functions, and the machining location parameters from where a part is made of a raw material blank. The numerical results predicted the part distortion phenomenon with an Absolute Error of 2.79% with respect to initial experimental measurements of part distortion. Additionally, the proposed approach was used to develop part distortion curves by considering the machining location of the specimen. From these, numerical optimization techniques led to determine the machining location of the representative specimen that attained lower distortions. Such location corresponded to a vertical value around of 3.15 mm for the two simulated residual stresses conditions in the material. An additional measurement was carried out to validate the optimal numerical results and errors below 3% were obtained. Consequently, the proposed approach can be of use to determine, to reduce and to optimize part distortion without further experimental testing in structural aluminum 7050-T7451 alloy aircraft components.
Fatigue Crack Analysis of Magnesium ZK60 V-Notched Specimen Using X-Ray Tomography
Authors: Albinmousa Jafar , Al-Dakheel Hussain , Temitope Idris , Al-Sadah Jihad , Muhammad Raashid 
Published: February 2021

Abstract
Magnesium alloys are attractive lightweight structural materials that have the potential to be used in aerospace, automotive and medical industries. However, fatigue is a major cause of failure in structural components. It is also known that notches, which are unavoidable, have a detrimental effect on fatigue resistance. Fatigue damage is associated with the formation of crack(s). Therefore, it is necessary to understand the fatigue crack growth behavior for better design analysis.
In this research, a V-notched specimen machined from ZK60 magnesium extrusion is tested under cyclic axial loading. Fatigue experiment was performed under completely reserved force-controlled loading with an amplitude of 12 kN and under standard laboratory conditions. The fatigue test was interrupted 14 times in order to perform ex-situ x-ray tomographic analysis using the Nikon XTH 225 ST system. The sample failed after 184,005 cycles. A gray-level thresholding process was performed using MATLAB on the selected slices to convert each pixel to either white or black color. Then, these slices were stacked using imaging software to make 2D representations of the crack surface at different cycles. As a result, the areas of the crack surfaces were measured for all scans. The result suggests an exponential relationship between the crack surface area and the number of cycles.
Atomistic Molecular Dynamics Simulation Based Failure Criterion of Polycrystalline Graphene Under Biaxial Loading
Authors: Shishir MD Imrul Reza , Tabarraei Alireza 
Published: February 2021

Abstract
Graphene sheets produced by chemical vapor deposition (CVD) are polycrystalline and the presence of grain boundaries (GBs) alter their mechanical properties relative to single-crystal graphene. In this study, we have performed a series of molecular dynamics simulations using REBO2+S potential in order to develop a failure criterion for infinite polycrystalline graphene sheets under biaxial tension. We have studied the effect of temperature on mechanical properties of polycrystalline graphene for both uniaxial and biaxial loading conditions. The normal stresses are normalized with respect to the corresponding uniaxial ultimate strength values and the normalized stresses are used to define the failure envelope of polycrystalline graphene. Our study suggests that a bilinear failure envelope or a circular failure envelope can be used to represent with reasonable accuracy the tensile strength of polycrystalline graphene under biaxial loading at different temperatures.
Strain Response and Aerodynamic Damping of a Swirl Distortion Generator Using Computational Fluid Dynamics
Authors: Hayden Andrew , Untaroiu Alexandrina 
Published: February 2021

Abstract
Boundary layer ingestion (BLI) concepts have become a prominent topic in research and development due to their increase in fuel efficiency for aircraft. Virginia Tech has developed the StreamVane™, a secondary flow distortion generator, which can be used to efficiently test BLI and its aeromechanical effects on turbomachinery. To ensure the safety of this system, the complex vanes within StreamVanes must be further analyzed structurally and aerodynamically. In this paper, the induced strain of two common vane shapes at three different operating conditions is computationally determined. Along with these observations, the aerodynamic damping of these vanes are calculated to predict flutter conditions at the same three operating points. Steady CFD calculations are done to acquire the aerodynamic pressure loading on the vanes. Finite element analysis (FEA) is performed to obtain the strain and modal response of the StreamVane structure. The mode shapes and steady CFD are used to initialize an unsteady CFD analysis which determines the aerodynamic damping of the vanes. The testcase used for this evaluation was specifically designed to overstep the structural limits of a StreamVane, and the results provide an efficient computational method to observe flutter conditions of stationary systems.
Multi-Fidelity Aerodynamic Modeling of a Floating Offshore Wind Turbine Rotor
Authors: Zhang Kai , Bilgen Onur 
Published: February 2021

Abstract
This paper presents a comparison of low- and mid-fidelity aerodynamic modelling of floating offshore wind turbine rotors. The low-fidelity approach employs the conventional Blade Element Momentum theory implemented in AeroDyn of OpenFAST. This model ignores the aerodynamic interactions between different blade elements, and the forces on the blade are determined from the balance between momentum theory and blade element theory. With this method, it is possible to calculate the aerodynamic performance for different settings with low computational cost. For the mid-fidelity approach, the Actuator Line Modeling method implemented in turbinesFoam (an OpenFOAM library) is used. This method is built upon a combination of the blade element theory for modeling the blades, and a Navier-Stokes description of the wake flow field. Thus, it can capture the wake dynamics without resolving the detailed flows near the blades. The aerodynamic performance of the DTU 10 MW reference wind turbine rotor is studied using the two methods. The effects of wind speed, tip speed ratio, and blade pitch angles are assessed. Good agreement is observed between the two methods at low tip speed ratios, while the Actuator Line Modeling method predicts slightly higher power coefficients at high tip speed ratios. In addition, the ability of the Actuator Line Modeling Method to capture the wake dynamics of the rotor in an unsteady inflow is demonstrated. In the future, the multi-fidelity aerodynamic modules developed in this paper will be integrated with the hydro-kinematics and hydro-dynamics of a floating platform and a mooring system, to achieve a fully coupled framework for the analysis and design optimization of floating offshore wind turbines.
High-Fidelity Structural Analysis of a 10 MW Offshore Floating Wind Turbine Rotor Blade
Authors: Yaghmaie Reza , Bilgen Onur 
Published: February 2021

Abstract
This paper presents a comparison of low- and high-fidelity structural analyses of a 10 MW offshore floating wind turbine rotor blade. For low-fidelity analysis, BeamDyn as a part of the OpenFAST toolset is used. For high-fidelity analysis, the Toolkit for the Analysis of Composite Structures (TACS) finite element method is used. First, several numerical examples with reference solutions from the literature are investigated to compare the accuracy and efficiency of the low- and high-fidelity structural models. Next, the DTU 10 MW reference wind turbine blade is analyzed using both the low- and high-fidelity methods. The bending response of the blade is analyzed. The results show that the high-fidelity model agrees with low-fidelity results and reference solutions. The high-fidelity model represents the deformations more accurately than the low-fidelity model and therefore is appropriate for structural analysis of complex wind turbine blade shapes.
Cutting-Tools Degradation Assessment for Structural-Steel Machining Centers
Authors: Huang Tsung-Ren , Chen Hao-Ting , Pan Min-Chun 
Published: February 2021

Abstract
To assess cutting-tools degradation, mounted accelerometers and current clamp probes were used to acquire machining vibration for both the band-saw machine and the drilling machine, of which a structural-steel machining center is composed. Significant features were first extracted through spectral analysis, and tool degradation assessment was conducted through using a supervised learning scheme, self-organizing map. The results reveal that 10% remaining useful life can be predicted before the band-saws and drills wore out.
Infusing Entrepreneurial Mindset Into Engineering Education: Five Strategies for Implementation Success
Authors: Lichtenstein Gary , Collofello James S. 
Published: February 2021

Abstract
The Ira A. Fulton Schools of Engineering (FSE) received a two-year grant to institutionalize entrepreneurial mindset (EM) throughout the college. This paper summarizes the history of entrepreneurial education in engineering, then reviews metrics of initial implementation success across 17, ABET-accredited programs. Five strategies were deployed during the implementation stage of the initiative, which strived to engage 66 faculty who taught one of three EM-focus courses in each undergraduate program: a first-year engineering course, a required design or technical course in the second or third year, and Capstone. Strategies were: 1) Adopting a 21st Century Engineer orientation to entrepreneurial education; 2) Operationalizing EM using a single, consistent framework across all courses and programs; 3) Modeling implementation based on ABET accreditation processes; 4) Infusing the initiative with substantial faculty support; and 5) Incentivizing faculty with stipends to promote initial implementation. Challenges revolve around sustaining implementation while improving effectiveness of EM instruction and assessment, particularly after grant funding. Lessons learned are that 1) institutionalization of the initiative needs to be strategized during initial implementation and 2) faculty are more likely to support an initiative that includes activities and outcomes about which they have always cared, including student success, professional development, and collegial interaction.
Modelling, Control and Design of a Clutched Parallel Elastically Actuated Articulated Robotic Leg Through Virtual Tunable Damping
Authors: Tanfener Emre , Candan Sinan Şahin , Turgut Ali Emre , Saranlı Uluç 
Published: February 2021

Abstract
In this study, design, modelling and control of a clutched parallel elastically actuated articulated leg is presented. Clutch mechanism is introduced to disengage the parallel elastic element when it is not needed. Some of the design principles concerning the ease of manufacturing and assembly are underlined. While the system has two joints at hip and knee that can be actuated, for simplicity, restrained motion of the system in vertical direction is considered only with hip actuation. Controller is based on a template model and the desired motion is obtained by equating (embedding) dynamics of the physical system (anchor) to the template model. Spring loaded inverted pendulum (SLIP) model including a virtual viscous damper is chosen as the template. Controller decides on the virtual damping constant in the template to reach desired apex positions. A wrapping cam mechanism is introduced to equate the potential energy function of the parallel spring to the desired linear spring of SLIP model. To complete embedding, necessary torque is calculated by equating the virtual works of the inputs. Overall, simulation of the hopping system and the important aspects of design are presented.
Investigation of Nonlinear Effects in a Bolted Joint Beam Using the Base Excitation
Authors: Doranga Sushil 
Published: February 2021

Abstract
In this paper, the nonlinearity detection, characterization and identification of a bolted beam assembly is presented. The new approach based on the force reconstruction using the base excitation as an input is used for the identification of nonlinear parameters. The nonlinear effect in the bolted beam assembly was induced by reducing the bolt clamping loads. A collection of frequency response functions (FRFs) are shown at different clamping loads to detect and characterize the nonlinearities. Once the nonlinearities are detected and characterized, the restoring force surface method using the reconstructed force was used to identify the nonlinear parameters in the modal space. Four different base excitation (energy) levels with three different tightening torques were considered in the tests in order to study the energy dependence of the damping nonlinearities. In all the cases, the nonlinear system identification methodology employed was successful in identifying the damping and stiffness nonlinearities.
Oklahoma City Contaminant Dispersion: Concentration Data Processing and Analysis for a Scaled Puff Release Experiment
Authors: Homan Ty 
Published: February 2021

Abstract
Magnetic resonance techniques were leveraged to obtain velocity and concentration measurements for a puff release contaminant dispersion study. The study involved a scaled model of downtown Oklahoma City as it was in 2003, and sought to provide a high fidelity, three-dimensional data set for comparison with JU2003 and subsequent studies. The scaled model was placed in a water channel with fully turbulent flow (Re = 36,000), and an MRI system was used to take scans at 12 time-specific measurement phases throughout the puff injection cycle. The present work details processing methods applied to the nearly 650 million magnetic resonance concentration (MRC) data points obtained from the study. Processing entailed the calculation of a concentration field through background subtraction and normalization involving several distinct scan types. Uncertainty was reduced through the scaling and combination of high molarity scans. Processing methods are followed by a preliminary investigation of the results, which highlights noteworthy elements of scalar transport within the data set and the need for further investigation of the complex flow field. The study ultimately demonstrates the applicability of magnetic resonance techniques to puff release and dynamic experimental conditions, as well as a method for working with data from phase-locked experiments.