bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Feasibility of Noise Insulating Materials With Variability of Frequencies and Amplitudes
Authors: Kitowski Zach , Marsh Andrew , Graves Roy 
Published: January 2020

Abstract
The objective of this experimental investigation was to determine the effectiveness of different thermal insulating materials noise reduction properties when exposed to acoustic signals of varying frequencies and amplitudes. The experimental system incorporated two boxes separated by a thermal insulation wall. A speaker was used in one box with varied sound amplitude and frequency to test how effective the insulating material was at reducing sound transmission through a wall. The sound level was measured with a microphone in each box and the values were used to calculate the Sound Transmission Loss (STL) for each trial. Fiberglass insulation and cork insulation were the two insulation materials tested. The frequency levels of500 Hz, 1000 Hz, and 2000 Hz were tested. A three factor ANOVA analysis was completed and the null hypothesis was rejected with 95% confidence for each of the three factors. A Tukey test was conducted to determine which factor, if any, had a significant impact on the STL value. The Tukey test determined that frequency had the most significant impact on the STL value followed by the material choice with the average difference of means for comparison groups being 17.92 dB and 7.74 dB, respectively. The Tukey test also determined sound level did not have a significant impact on the STL value. The fiberglass insulation tested had the highest STL value of the two materials tested, with a maximum STL of 49.5 dB at 2000 Hz while the minimum STL was 26.2 dB at 500 Hz. The cork insulation had a maximum STL of 44.4 dB at 2000 Hz and a minimum STL of 10.5 dB of 500 Hz. At 1000 Hz however, the cork insulation had a higher STL than the fiberglass insulation with 32.6 dB and 31.6 dB respectively. This discrepancy might be due to a specific property of the cork dictating how it interacted within a specific frequency range. The test had an overall uncertainty of ±1.34 STL which was much smaller than the difference between sample groups. The ANOVA analysis also showed a strong interaction between the insulating material and the frequency as it had a much greater F-value of 869.56 as compared with the F-critical value of 2.42.
Sensitivity of Thermal Transport in Uranium Dioxide to Fission Gas
Authors: Mitchell Katherine , Horner Hunter , Resnick Alex , Park Jungkyu , Farfán Eduardo B. , Yee Tien , Hummel Andrew 
Published: January 2020

Abstract
Understanding the effect of fission gas generation on thermal resistance in various nuclear fuels is critical for managing fuel performance. Fission gas in the fuels degrades its thermal properties by altering the lattice vibrations. It results in thermal expansion that increases the thermal resistance and decreases the structural stability of the fuels. In this research, thermal transport in uranium dioxide is studied at a microscopic level when Xe and Kr gasses interact with uranium and oxygen atoms. Reverse non-equilibrium molecular dynamics (RNEMD) is used to calculate the thermal resistances and provide an understanding about the effect of the fission gas release on phonon transport. The results show that the thermal conductivity of uranium dioxide is decreased nearly by 78% by the presence of only one fission gas bubble. The thermal transport in uranium dioxide is shown to become highly diffusive by a single fission gas bubble and a large temperature drop in temperature profiles are observed in all simulation structures with fission gas bubbles. The average interfacial thermal resistance across a fission gas bubble is estimated to be 2.1 × 10−9 Km2/W.
Transverse Vibrations of Annular Spinning Disk Subjected to Out-of-Plane Loads and Uniform In-Plane Follower Edge Forces
Authors: Guan Peng , Peng Meng , DeSmidt Hans , Yao Wei 
Published: January 2020

Abstract
This paper investigated the transverse vibration natural frequency and stability of an annular spinning disk subjected to concentrated uniform in-plane edge follower forces and out-of-plane loads including mass, damper, and spring. Linear plate theory is used to derive the plate model used in this research, both symmetric in-plane stress fields, due to plate rotation, and asymmetric in-plane stress fields, due to uniform edge follower forces, are considered. The asymmetric stress, which is a function of the rotation of the plate, is obtained from the steady-state response of the coupled in-plane vibration equations. The concentrated in-plane follower edge forces are expanded as Fourier series and the produced stress fields are also achieved from the corresponding Fourier components. To explore the system stabilities, natural frequency variations, in-plane and out-of-plane loads coupling effects, and the instability types, the eigenvalues are plotted with respect to rotation speeds. Based on the eigenvalue analysis, the effects of concentrated edge uniform follower forces on a spinning disk system with out-of-plane loads were concluded.
Numerical Analysis on Evaporation Assisted Convective Cooling: Effect of Surface Morphology
Authors: Saha Sudipta , Tikadar Amitav , Khan Jamil , Farouk Tanvir 
Published: January 2020

Abstract
With an escalating need to find ways to reduce the water consumption in industrial cooling system, on-demand hybrid cooling has been a topic of great interest. The main concept of this cooling method is centered upon the utilization of huge exchange of enthalpy associated with phase change process in a conventional convective cooling system. In this study, a multidimensional multi-physics model has been employed to study a system that undergoes this dual mode cooling process where both convection and evaporation contribute to the heat transfer process. The computational domain considered is comprised of a thin liquid film that undergoes evaporation with constant heat flux provided from the bottom and a convective loading of laminar air flow above it. Evaporation takes place at the liquid-gas interface and the evaporated mass is being carried away by the incoming air, hence augmenting the convective cooling through the phase change process. This is an extension of our prior work where the surface structure modification (i.e. undulated surface) on the performance of this proposed hybrid cooling method is numerically investigated. Array of hemispherical structures have been introduced as the surface introducing the heat flux to the liquid film. The objective is to increase the surface to volume ratio and decrease the thermal resistance across the liquid film. The predictions indicate that with the increase in the height of the undulated surface the thermal resistance across the liquid film tends to decrease. Results from these simulations show that a ∼50% reduction in the thermal resistance can be achieved by the surface structure modification while the net evaporation flux can be doubled compared to a flat film configuration.
Efficiently Predicting Fatigue Life of Drill Collars With Ports Subjected to Variable-Amplitude Bending or Torsional Loads
Authors: Song Fei , Li Ke , Ossia Sepand 
Published: January 2020

Abstract
To enable real-time monitoring of the physical condition of the drilling equipment such as drill collars, a methodology for efficiently predicting the fatigue life of ports subjected to variable-amplitude cyclic bending or torsional loads is needed. In this paper, such a method is reported, which involves several steps. Firstly, elastic finite element analysis (FEA) of a collar port was performed to determine the elastic stress states with unit loads. Secondly, the unit load-based linear elastic solutions with the loading history were superimposed to produce a time history of the stress tensor. Thirdly, the previously established pseudo-elastic stress states were transformed into the true elastoplastic stress and strain states with a cyclic plasticity model and a notch correction rule. Finally, the cumulative fatigue damage was computed with the rainflow counting algorithm and a damage accumulation rule. The resulting fatigue life predictions for the ports were found to agree favorably with the experimental measurements from full-scale fatigue tests of port-containing collar samples with variable-amplitude loads. This newly developed method can be used to predict the remaining useful life of a port in real time with the loads resulting from downhole measurements or a drill string dynamics simulation code.
Simulations of Online Non-Destructive Acoustic Diagnosis of 3D-Printed Parts Using Air-Coupled Ultrasonic Transducers
Authors: Rooney Sean , Pochiraju Kishore 
Published: January 2020

Abstract
The open-loop process by which 3D printers operate often leads to significant time and material losses due to print failures. A challenge in Additive Manufacturing (AM) is assessing 3D-printed parts mid-print for the dimensional stability of the internal structures and their microstructure and material properties. These internal features are typically opaque to visual inspections after print and can only be accessed for property characterization if the part is cut open. An assessment of methods for evaluating parts in situ using air-coupled ultrasonic transducers in this paper. The purpose is to determine the microstructure and limited effective properties (density and modulus) of internal structures during the print process using acoustic methods. We examine the effectiveness of acoustic wave reflection, absorption and propagation through the infill channels, which make up a part on a fused deposition modeling printer to obtain dimensional measurements while the part is on the print bed. We simulated the acoustic wave response for common frequencies of commercially-available air-coupled transducers (25–300 kHz) placed near simulated 3D-printed parts. We compared the return signals using the k-Wave Acoustics Toolbox, a time-domain model for acoustic wave propagation, and validated these simulations with physical readings. The results showed the behavior of the peak amplitude of the received signals for various materials and infill channel lengths. Simulations and physical experiments were conducted for both through-transmission and pulse-echo approaches. The simulations optimize parameters for a maximized peak received signal strength. The results will limit the scope of computationally expensive methods of observing obfuscated structural deficiencies and deformations in a 3D-printed part in situ using air-coupled ultrasonic transducers and similar ultrasonic NDE technologies.
Anisotropic Yielding Behaviour of Inconel 718 Alloy at Elevated Temperatures
Authors: Mahalle Gauri , Salunke Omkar , Kotkunde Nitin , Gupta Amit Kumar , Singh Swadesh Kumar 
Published: January 2020

Abstract
The study of anisotropic deformation behavior of material plays a key role in optimizing the hot working process parameters. Further, trustworthiness of Finite Element (FE) analysis in hot working condition is highly dependent on accurate input of mechanical properties and anisotropic yield parameters. In present work, two different anisotropic yield criteria, namely; Hill 1948 and Barlat 1989 are developed from Room Temperature (RT) to 500 °C and different slow strain rate conditions (0.01, 0.001 and 0.0001 s−1) for Inconel 718 alloy. First, uniaxial tensile test carried out from RT to 500 °C with an interval of 100°C and at quasi-static strain rate conditions at different orientation of a sheet (0°, 45° and 90°). Based on the tensile test data, extended Von-Mises isotropic criterion i.e. Hill 1948 and Barlat 1989 yield criterion were developed at different conditions. The predictability of yield criteria has been verified using yield loci, variation of anisotropic coefficient and yield stresses. The various static parameters such as correlation coefficient, relative error and standard deviation are considered to compare the yield criteria. Based on the comparison, Barlat 1989 yield criterion shows good in agreement with experimental data.
Performance Analysis of a Novel Parallel Turbine Reheat Cycle for High Speed Vehicles
Authors: Sun Jingchuan , Xu Guoqiang , Wen Jie , Dong Bensi , Zhuang Laihe , Liu Qihang 
Published: January 2020

Abstract
The optimization of the Brayton cycle has gained an increasing worldwide attention due to improve the specific thrust for achieving super cruise. This paper proposes a novel Parallel Turbine Reheat (PTR) cycle, which the second combustor would be placed at bypass of the expansion process, and presents an analytical methodology by which PTR can be simulated at ideal state and actual state. The motivation and the working principle of the PTR cycle are explained in detail. A performance simulation model for the PTR cycle is established with the assumption of equilibrium fuel rich gas as the working fluid in the gas generator. Then parametric cycle studies are performed with the variation of temperature rise ratio of the parallel combustion chamber and bypass ratio at the flight Mach number of 0 and 1.5 respectively. The interrelationships between cycle parameters and their effects on cycle performance are discussed. The results show that the specific thrust will be increased to 20% comparing with the conventional cycle for the reason that makes more fuel energy convert to the propulsion power without increasing the inlet temperature of turbines. The cycle parameters for a practical PTR cycle engine are more applicable for the flight speeds of Mach 1.5. The predicted engine performance shows that the PTR cycle concept exhibits a competitive specific thrust with respect to engine in the state of non-afterburning, and might be a promising propulsion system for super-cruise air-breathing flying vehicles.
Ballistic Penetration Performance of a Unidirectional Woven Basalt Fiber Laminated Protective Armor
Authors: David N. V. , Zurina A. , Aziz M. R. , Rafiq M. N. , Syafiq M. , Sundram Raja 
Published: January 2020

Abstract
Contemporary military and other law enforcement operations are technology-driven with weapons and ammunition that demand a flexible, damage- and moisture-resistant, and lightweight protective materials with superior energy absorbing capacity. Ballistic fabrics made from high performance synthetic fibers such as para-aramid and natural fibers including basalt, and composites utilizing these fabrics, are among the leading materials for armor systems. Basalt fibers, which are extracted from igneous volcanic rocks, are natural fibers with mechanical and thermo-physical properties that are generally comparable or superior to glass and other synthetic fibers at a lower cost. This gives basalt-based composites an edge over existing materials for potential application as anti-ballistic protective panels. The aim of the present study is to experimentally determine the V50 performance and penetration resistance of a unidirectional woven basalt fiber laminated epoxy system at three different combinations of ply orientations [0, 45 and 90 degrees at both CW and CCW directions] consisting of 48 layers of the woven fabric. The V50 performance test was conducted in accordance to the MIL-STD-662F standard using the Universal Test Gun model UZ-2002. The V50 ballistic velocity are computed based on a minimum of six shots including three complete penetrations and three partial penetrations. The optimum number of layers of the basalt fabric to sustain the reference penetration velocity of 367 m/s corresponding to threat level II of the NIJ Standard-0101.04 are calculated for the current test specimen for future development.
Numerical Investigation on Strain Properties of Ti6Al4V Alloy Processed by Constrained Bending and Straightening Severe Plastic Deformation
Authors: Mwita W. M. , Akinlabi E. T. 
Published: January 2020

Abstract
This paper presents a numerical investigation on strain properties of Ti6Al4V alloy processed by constrained bending and straightening (CBS) severe plastic deformation (SPD) technique. CBS is a new SPD method that has been proposed to enhance continuous processing of metal sheets and improve magnitude and homogeneity of induced properties such as strain. The model considers a rectangular sheet of Ti6Al4V alloy processed with CBS at 2, 4 passes denoted as N2, N4 each combined with 10, 5, 3 mm feed length denoted as F10, F5, F3 respectively. ABAQUS Standard FEA Software was used to simulate and investigate the magnitude and homogeneity of equivalent plastic (EP) strain induced in material. Results show that for all feeds, magnitude values of EP strain at N4 passes were higher than those at N2 passes. The magnitude of EP strain increased with the number of passes. Values of both magnitude and homogeneity of EP strain were highest at F3 feed followed by those at F5 and F10 feeds respectively. The study has promised that CBS is the potential process for continuous production of metal sheets with improved EP strain magnitude and homogeneity.
A Real-Time Image Matching Algorithm for Binocular Stereo Measurement System
Authors: Duan Jianyu , Sun Lingyu , Li Lijun , Dai Zongmiao , Xiong Zhenkai , Wang Jinxi 
Published: January 2020

Abstract
Binocular stereo measurement system can obtain accurate three-dimensional information from two-dimensional images. It has been widely applied in many fields such as vehicle tracking, robot navigating, automatic crane lifting, as well as other fields. The crucial step of binocular stereo measurement is image matching. For the image matching, it is a great challenge to ensure both real-time and matching accuracy simultaneously. The image matching algorithm has a great influence on the image matching time and accuracy. In this paper, a real-time image matching algorithm for binocular stereo measurement system is proposed based on Speedup Robust Features (SURF) algorithm. In the proposed algorithm, firstly, the key feature points are identified by the original SURF algorithm method. Secondly, the main direction of the key feature point is determined by intensity centroid method. Then, the feature descriptor is calculated by the BRIEF binary method so that the time of feature description can be shortened. Finally, RANSAC (Random Sample Consensus) method is adopted to remove mismatching points. The experiments results show that the proposed algorithm can shorten image matching time obviously and improve the accuracy of matching points.
Amplitude-Frequency Response for Superharmonic Resonance of Fourth Order of Electrostatically Actuated MEMS Cantilever Resonators
Authors: Caruntu Dumitru I. , Reyes Christopher 
Published: January 2020

Abstract
This paper deals with the frequency response of superharmonic resonance of order four of electrostatically actuated MicroElectroMechanical Systems (MEMS) cantilever resonators. The MEMS structure in this work consists of a microcantilever parallel to an electrode ground plate. The MEMS resonator is elelctrostatically actuated through an AC voltage between the cantilever and the ground plate. The voltage is in the category of hard excitation. The AC frequency is near one eight of the natural frequency of the resonator. Since the electrostatic force acting on the resonator is proportional to the square of the voltage, it leads to superharmonic resonance of fourth order. Besides the electrostatic force, the system experiences damping. The damping force in this work is proportional to the velocity of the resonator, i.e. it is linear damping. Three methods are employed in this investigation. First, the Method of Multiple Scales (MMS), a perturbation method, is used predictions of the resonant regions for weak nonlinearities and small to moderate amplitudes. Second, the Homotopy Analysis Method (HAM), and third, the Reduced Order Model (ROM) method using two modes of vibration are also utilized to investigate the resonance. ROM is solved through numerical integration using Matlab in order to simulate time responses of the structure. All methods are in agreement for moderate nonlinearities and small to moderate amplitudes. This work shows that adequate MMS and HAM provide good predictions of the resonance.
Adaptation of an Existing Impeller Design to Large Bore Requirements: Aerodynamic Considerations
Authors: Jariwala Vishal , Larosiliere Louis 
Published: January 2020

Abstract
Multistage process centrifugal compressor applications with single shaft rotors supported by only two bearings are quite common. It is sometimes desirable to operate impellers at higher rotational speeds, resulting in relatively compact and cost-effective machines. Such high-speed rotors can, however, pose rotordynamic challenges, and therefore require larger shaft or impeller bore diameters to increase rotor stiffness and rotordynamic stability. This work explores aerodynamically favorable ways to adapt an existing standard bore impeller design to large bore requirements. First, the stage aerodynamic performance and flow range implications of increasing bore diameter are discussed using meanline modeling and vector diagram arguments. Some strategies for adapting a standard bore design to large bore variant are then presented. Attempts are made to identify and clarify technical limitations to the degree of adaptability of an existing impeller to large bore requirements. Finally, a CFD-backed case study on a large-bore adaptation of a particular stage is presented to clarify practical considerations.
Coupled Flexural and Torsional Vibration Analysis of Composite Beams
Authors: Sarfaraz Ehsan , Afolabi Jeremiah O. , Hamidzadeh Hamid R. 
Published: January 2020

Abstract
An analytical method is presented to determine the dynamic response of a coupled flexural and torsional vibration of composite beams. The general governing equations of motion are presented and a closed form solution for free vibration of the composite beam that demonstrates both geometric and material coupling is developed. The proposed solution is used to compute the natural frequencies, modal loss factors, and mode shapes of the composite beam for several modes of the coupled bending and torsional vibrations for any boundary conditions. In this analysis, hysteretic damping for the composite beam is considered and its effects on mode shapes and modal loss factors are determined. In addition, the variation of modal parameters such as bending displacement, bending slope, torsional rotation, shear force, bending moment, and torque along the beam for the first four mode shapes are presented for the clamped-free boundary conditions. Moreover, to verify the validity of the presented analytical method, results for the cases with no damping are compared with the previously established results and good agreement is achieved. The presented results can provide a guideline for selecting appropriate geometries and materials to design composite beams.
Vibration Absorption in a Nonlinear Metamaterial Beam Incorporating Shape Memory Alloys
Authors: Fernandes Ralston , Boyd James G. , El-Borgi Sami , Lagoudas Dimitris C. 
Published: January 2020

Abstract
Locally resonant metamaterials are capable of demonstrating low-frequency vibration absorption due to the formation of stop-bands. In this work, the multi-mode vibration absorption capability of an adaptive nonlinear metamaterial beam is investigated. The metamaterial beam is idealized as a hinged-hinged finite Euler-Bernoulli beam with a von-Kármán geometric type nonlinearity that is attached to a distributed cellular array of shape memory alloy (SMA) spring–mass resonators. Numerical studies are performed to evaluate the effects of dissipation and change in elastic modulus due to material phase change of SMA pseudoelasticity on the dynamic response of the beam. Using a modal analysis approach, stop-bands are generated at the first three nonlinear frequencies of the beam. The frequency response demonstrates a hardening behavior at a temperature significantly higher than the austenite finish temperature while conversely demonstrating a softening behavior at a temperature slightly above the austenite finish temperature.