bluuebunny/crossref_metadata_2025_split huggingface dataset:
Aspects of Strain Rate Effects on Some Composite Materials
Authors: Ayorinde Emmanuel O. 
Published: November 2021

Abstract
Effects of moderate straining speed on the material and damage characteristics of beam samples of graphite/epoxy and E-glass/epoxy composites were investigated. The basic fiber architecture utilized was unidirectional, axial layup, but data was also obtained for the 45-degree orientation. Ultrasonic and acoustic emission (AE) inspections were utilized. The acoustic emission records show matrix cracking. The ultrasonic images revealed the regions of failure. The results show that in general, strain rate notably affects material and damage properties.
Damping Properties of Vapor-Grown Carbon Fiber Composites
Authors: Finegan Ioana C. , Tibbetts Gary G. , Gibson Ronald F. 
Published: November 2021

Abstract
The objective of this paper is to investigate analytically and experimentally the dynamic mechanical properties of vapor grown carbon fiber (VGCF)/thermoplastic composites. The experimental results show that, as predicted, very low fiber aspect ratios may produce significant improvements in damping. Since VGCF have submicron diameters and lengths, with a fiber aspect ratio, l/d = 19, good dynamic properties are obtained by using them as reinforcement in a thermoplastic. Fiber length distributions and orientation in the injection molded samples are determined by scanning electron microscopy (SEM). An analytical model based on the elastic-viscoelastic correspondence principle is developed to predict elastic properties in short fiber composites having a preferential fiber orientation in the direction of injection. The mechanical damping and storage modulus are analyzed experimentally by using a Dynamic Mechanic Analyzer (DMA).
Acoustic Microscopy for Bone Characterization
Authors: Kundu Tribikram , Jorgensen Claus 
Published: November 2021

Abstract
Characterization of animal bones by acoustic microscopy is a relatively new field of research. Non-uniformity of bones requires a complete analysis of the interaction between the focused acoustic beam and the bone specimens for its characterization. The complete analysis produces the V(z) curve taking into account the lens angle and the elastic properties of the bone. V(z) oscillations may be generated by surface skimming Rayleigh waves and/or P-waves in different parts of the bone depending on the bone properties. In this paper after a short review of different applications of the acoustic microscopy technique a complete theory of the V(z) curve synthesis is briefly presented. A number of V(z) curves are analytically generated following this theory. These curves sometimes show a regular oscillatory shape as predicted by the simple ray theory. However, often the synthesized V(z) curves show irregularities. The synthesized V(z) curve for silicon has been compared with the experimental results to have a confidence on the analytical computation. Then additional numerical exercises are carried out to understand why sometimes the V(z) curve shapes are irregular, and whether the P-wave speed and/or the Rayleigh wave speed of the material can be extracted from such irregular shaped V(z) curves. After understanding the V(z) phenomenon the wave speeds at different points of a bone are experimentally measured from its V(z) curves.
Comparison of the Flame Characteristics of Circular and Elliptic Jets in a Cross-Flow
Authors: Gollahalli S. R. , Pardiwalla D. 
Published: November 2021

Abstract
This study was directed to understand the coupling effects of the noncircular geometry of the burner and a cross-flow on the combustion of gas jets. This paper compares the characteristics of propane jet flames from circular (diameter = 0.45 cm) and elliptic (major axis = 0.75 cm, minor axis = 0.26 cm) burners of equivalent exit area in a cross-flow. The elliptic burner was oriented with its major axis or minor axis aligned with the cross-flow. Experiments were conducted in a wind-tunnel provided with optical and probe access and capable of wind speeds up to 12.5 m/s. The burners were fabricated with metal tubes. Instrumentation included a Pt-Pt/13%Rh thermocouple, a quartz-probe gas sampling system, chemiluminescent and non-dispersive infrared analyzers, a video-recorder, and a computer data acquisition system. The measurements consisted of the upper and lower limits of jet velocity for a stable flame, flame configuration, and visible length. Flame structure data including temperature profiles and concentration profiles of CO2, O2, CO, and NO were obtained in a two-zone flame configuration where a planar recirculation exists in the wake of the burner tube followed by an axisymmetric tail. Emission indices of CO and NO were estimated from the composition data. Results indicate that the upper and lower limits of the fuel jet velocity increase with the cross-flow velocity for all burners, and the rate of increase is highest for the elliptic burner with its minor axis aligned with the cross-flow. That burner configuration also produces the longest flame. The emission indices show that the CO production is lower and NO production is higher for elliptic burners than for circular burners in cross-flow. Also, aligning the minor axis of the elliptic burner with the cross-stream is superior in terms of flame stability and emissions of NO and CO.
Simulation of Methanol Combustion in the NIST Reference Spray Combustor
Authors: Crocker D. Scott , Giridharan M. G. , Widmann John F. , Presser Cary 
Published: November 2021

Abstract
This paper describes the simulation of a methanol spray flame in the NIST reference spray combustion facility, which was predicted using a state-of-the-art, unstructured-mesh CFD code. The code solves the gas-phase equations in an Eulerian frame using the finite-volume approach while the droplet equations are solved in a Lagrangian frame. This paper focuses on the sensitivity of the predicted flame structure to the model boundary conditions, to ensure matching of the simulation to the experimental conditions. The combustor uses a simplex pressure-jet atomizer to produce a hollow-cone spray with a cone angle of 60°. The overall equivalence ratio of the baseline operating condition is 0.29. The spray initial conditions are specified from the measurement data obtained close to the atomizer. For this case, several simulations were performed with different initial and boundary conditions. The parameters that were varied from the baseline case included the air swirl velocity, equivalence ratio, spray droplet size distribution, and a pre-exponential kinetic constant. The results indicate that the existence of a central recirculation zone is sensitive to the location and rate of heat release. The predicted flame structure appears to be in reasonable agreement with NIST flame visualization. The fuel conversion is predicted to be 100 % whereas the data indicates a conversion of 80 %. This discrepancy is attributed to the uncertainty in spray initial conditions, especially for the droplet size distribution.
Size Scale Dependence of Deformation in NiTi
Authors: Gall Ken , Dunn Martin L. , Liu Yiping , Labossiere Paul , Sehitoglu Huseyin , Chumlyakov Yuriy I. 
Published: November 2021

Abstract
Recent work [1-5] has suggested that a lucrative future for shape memory materials such as NiTi is in the area of micro-electro-mechanical systems (MEMS). To design MEMS and predict their behavior during service, we must have quantitative information on the mechanical properties of scaled down NiTi materials. One way of obtaining the mechanical properties of scaled down materials is with unique MEMS testing fixtures. Although this approach is favorably analogous to macroscopic testing techniques it is not always feasible owing to the difficulty of handling the microscopic samples. Many smart material actuators are deposited thin films [1-5] and separating the films from their substrate and subsequently testing them is beyond our current MEMS processing and handling tools. An alternative method to quantify the properties of microscale materials is through micro-indentation, which has been previously applied to NiTi polycrystals [6]. Although micro-indentation is simple to accomplish, interpretation and quantification of the results is not as straightforward, as will be demonstrated in this work.
Stress Induced Martensitic Transformation in Shape Memory Alloys Studied by In-Situ Neutron Diffraction Techniques
Authors: Šittner P. , Novák V. , Lukáš P. , Neov D. 
Published: November 2021

Abstract
Shape memory alloy (SMA) elements are being embedded in smart materials and hybrid composites as actuating and/or sensing elements responding to the stress and temperature stimuli. In order to design smart composites, in-situ experimental information about evolution of internal stresses and phase fractions in the embedded SMA elements and internal stresses in neighboring matrix during actuation cycles would be of interest. Such experimental data have to be obtained nondestructively from the microscopic particles or fibres deep in the bulk specimens exposed to stress and/or thermal variations. In-situ neutron diffraction experimental techniques fulfill in principle these requirements. However, reliable evaluation of internal stresses from neutron diffraction experiments in the smart SMA composites can be made only after the lattice plane responses of monolithic SMAs in thermomechanical cyclic loads are fully understood. In this paper, the results of the in-situ investigations of stress induced martensitic transformation (SIMT) in tensile tests carried out on monolithic CuAlZnMn SMA polycrystal are reported, and the observed lattice plane responses are interpreted using a selfconsistent model of SMA polycrystal.
Power Consumption for Active Acoustic Control of Launch Vehicle Payload Fairings
Authors: Griffin Steven F. , Lane Steven A. , Leo Donald J. 
Published: November 2021

Abstract
Vibroacoustics during space vehicle launch has been blamed for as many as 60% of first day satellite failures. At the Air Force Research Laboratory in Albuquerque NM USA, modeling and analysis was performed to determine the feasibility of monolithic piezoceramic actuators and active acoustic control to reduce noise transmission during launch of the OSP launch vehicle with a hypothetical composite fairing. Voltage, power and energy were studied as a function of transmission reduction. The conclusion reached for the case explored in depth was that off-the-shelf monolithic piezoceramic actuators did not have sufficient control authority to reduce noise transmission at realistic sound levels.
Mechanical Characterization and Design of Shape Memory Alloy Composites for Functionally Graded Adaptive Structures
Authors: Bruck Hugh A. , Moore Charles L. 
Published: November 2021

Abstract
Shape Memory Alloys (SMAs) are being embedded in smart structures for sensing and actuation. The resulting structure is a composite material that possesses a heterogeneous architecture, requiring a system-based approach to optimize its design. In order to develop this approach, it is necessary to determine appropriate thermomechanical models for designing heterogeneous smart structures. In this investigation, the constitutive and actuation behavior of SMA wire-reinforced epoxy composites are charaacterized. A structural model is then verified for predicting the actuation behavior of functionally graded adaptive structures fabricated from SMA composites.
MR Fluid Sponge Materials and Devices
Authors: Carlson J. David , Chrzan Michael J. 
Published: November 2021

Abstract
Stable, high-strength, magnetorheological (MR) fluids and devices such as rotary brakes and linear vibration dampers that enable the benefits of controllable fluid technology are now commercially available. Recently, a new way of using MR fluids in which the fluid is contained in an absorbent matrix has been developed. Such MR fluid sponge devices enable the benefits of controllable MR fluids to be realized in cost sensitive applications. Most of the high-cost components normally associated with a fluid filled device can be eliminated with this approach. Low-cost, controllable MR fluid sponge dampers are particularly appropriate for moderate-force vibration control problems where a high degree of control authority is desired such as a new generation of high-performance, home washing machines now being developed.
Estimation of Soil Resistance Using a Strain Gauge Array
Authors: Adamchuk Viacheslav I. , Morgan Mark T. , Sumali Hartono 
Published: November 2021

Abstract
A vertical smooth blade with an array of strain gauges was designed to continuously measure mechanical resistance of soil at multiple depths. As the blade (tapered cantilevered beam) cuts through the soil, strain gauges detect deformation caused by varying soil resistance. Recorded strain data was used to estimate resistance pressure at different depths that cause the same deformation of the blade with known geometry and material properties. Verification of the analytical solution was performed in the laboratory by applying varying combinations of static loads, and numerically by finite element modeling. Field tests involved on-the-go measurement of integrated resistance pressures that were compared to cone penetrometer readings obtained from corresponding spots within the field.
Distributed Piezotransducers for Damage Detection
Authors: Kawiecki Grzegorz 
Published: November 2021

Abstract
The purpose of this paper is to show the feasibility of applying neural networks and arrays of piezotransducers for condition monitoring of basic structural components. It is shown that simple neural networks can be used to interpret damage-related anomalies in signals transferred between elements of a piezotransducer array. These relatively low frequency signals in the 0 Hz–1 kHz range carry enough information to determine damage location and size with a reasonable accuracy. The feasibility of a neural network-based expert system for signal processing is shown using a simple closed-form model of a thin, homogeneous vibrating plate. A new type of a rosette piezotransducer is presented. This type of a piezotransducer can generate and sense complex strain fields containing more damage-related information.
Dielectric Response of Adaptive Piezoelectric Sensoriactuators
Authors: Vipperman Jeffrey S. , Li Deyu 
Published: November 2021

Abstract
This paper closely examines the nature of the dielectric response of piezoceramics that are used as Adaptive Piezoelectric Sensoriactuators (APSAs). Firstly, it is demonstrated that he APSA possesses real time structural health monitoring abilities, based on the capacitance measurement of the piezoceramic. Secondly, nonideal behavior including lossy, hysteretic, and field dependence is measured in the piezoceramics and a method mitigating some of this response in the Adaptive Piezoelectric Sensoriactuator is proposed.
Nonlinear Coupled Transverse and Axial Vibration of a Compliant Structure: Free and Forced
Authors: Han Seon M. , Benaroya Haym 
Published: November 2021

Abstract
A compliant tower in the ocean environment is modeled as a beam undergoing coupled transverse and axial motion. The beam is supported by a torsional spring and has a point mass at the other end. It is assumed that the strains are small but the rotation is moderate compared to the strain so that the equations of motion for the axial and transverse motion are nonlinearly coupled. The nonlinear coupled equations of motion are derived here using Hamilton’s principle. The forced responses due to random waves are observed here. The responses are obtained numerically using the finite difference approach.
Non-Standard Reduction of Noisy Structural Systems: Shallow Arches
Authors: Vedula Lalit , Sri Namachchivaya N. 
Published: November 2021

Abstract
The dynamics of a shallow arch subjected to small random external and parametric excitation is invegistated in this work. We develop rigorous methods to replace, in some limiting regime, the original higher dimensional system of equations by a simpler, constructive and rational approximation – a low-dimensional model of the dynamical system. To this end, we study the equations as a random perturbation of a two-dimensional Hamiltonian system. We achieve the model-reduction through stochastic averaging and the reduced Markov process takes its values on a graph with certain glueing conditions at the vertex of the graph. Examination of the reduced Markov process on the graph yields many important results such as mean exit time, stationary probability density function.
Stability of High-Speed Milling
Authors: Insperger Tamás , Stépán Gábor 
Published: November 2021

Abstract
The stability charts of high-speed milling are constructed. Non-conventional unstable regions and vibration frequencies are identified. These are related to flip bifurcation, i.e. period doubling vibrations occur apart of the conventional self-excited vibrations typical for turning or low-speed milling with multiple active teeth. A new stability criterion is proposed and applied for the delayed parametric excitation model of milling.
Optimization of Gearshifting in Automatic Transmissions
Authors: Haj-Fraj Ali , Pfeiffer Friedrich 
Published: November 2021

Abstract
A method for the optimization of gear shift operations in automatic transmissions is proposed in this paper. Based on a mechanical model of the power train the control parameters for the clutch pressure as well as those for the load-reduction are optimized in order to improve the performance of the automatic transmission with respect to passengers comfort and gear shift duration. Scalar criteria, which are capable of describing these effects are formulated. The nonlinear optimization problem is solved with a sequential quadratic programming algorithm. The results show a significant improvement in terms of the optimization criteria.
On the Coupled Flap-Lag Bending Vibration of Propeller Blades: An Exact Dynamic Finite Element Formulation
Authors: Hashemi S. M. , Richard M. J. 
Published: November 2021

Abstract
An exact Dynamic Finite Element (DFE) approach for the coupled Flap-Lag vibration of blades is presented. DFE can be considered as a combination of the Finite Element Method (FEM) and the Dynamic Stiffness Matrix (DSM) formulations. The weighted residual method is used and the weighting and shape functions are chosen referring to the appropriate closed form solution of the non-coupled member equations. Based on the DFE approach, the natural frequencies for a scaled propeller blade are calculated and they are compared to the experimental data and other existing results.
Hydroadhesive Gripping by Using the Peltier Effect
Authors: Seliger Günther , Stephan Jörg , Lange Stephan 
Published: November 2021

Abstract
The automated handling of non-rigid sheet material, especially wovens, has to meet the requirements of damage free gripping independently of the material behavior. In this paper, a survey of different physical principles for grippers is given. Hydroadhesive gripping with frozen water as active medium has been selected as the most promising approach. Based on this principle, a novel hydroadhesive gripper prototype has been developed. The gripping process has been mathematically and numerically modeled and validated by experimental results. The analytical method enables to calculate the process parameters like gripping time, Peltier-Module geometry as well as holding forces in designing for implementation.
Dynamic Error Prediction and Compensation of Coordinate Measuring Machines
Authors: Dong Chensong , Zhang Chuck , Wang Ben , Zhang Guoxiong 
Published: November 2021

Abstract
Coordinate measuring machines (CMMs) are already widely used as a measuring tool in the manufacturing industry. Fast probing is now the trend for next generation CMMs. However, increases in the measuring velocity of CMMs are limited by dynamic errors that occur in CMMs.
In this paper, theoretical analysis and experimental research is used to create a systematic approach for modeling the dynamic errors of a touch-trigger probe CMM. First, an overall analysis of the dynamic errors of CMMs is given, and methods to improve the stiffness of air bearings are presented. Weak elements of the CMM are identified with a laser interferometer. The probing process, as conducted with a touch-trigger probe, is analyzed and dynamic errors are measured. Based on these analyses, the dynamic errors in touch-trigger probing are modeled using neural networks. In turn, dynamic errors are predicted. An approach to achieving software error compensation is discussed. Finally, the method and results from this study illustrate that it is possible to compensate for dynamic errors of CMMs.
Fixture Configuration Design Using a Computer Experiment
Authors: Xie L. Shelley , Hu S. Jack , Li Wei , Sudjianto A. 
Published: November 2021

Abstract
A new approach to fixture configuration design is developed based on the design and analysis of computer experiments (DACE). In the past, fixture configuration design undergoes three steps in an iterative manner: locator position design, clamp position design, and clamping force design. The fixture and workpiece were generally assumed to be rigid bodies. In this study, a sampled computer experiment is conducted with a finite element analysis (FEA). Surrogate models are developed based on the responses of this experiment. The purpose of building these models is to represent complex physical relations among the design variables in a simple functional form such that design analysis can be conducted efficiently. The surrogate response models can be used to provide a directional guidance in optimization, to identify feasible fixture configuration designs for flexible workpieces, and more importantly to enable a simultaneous design of locator/clamp positions and clamping forces. In the surrogate models workpiece deflections and locator reaction forces are used as variables. Distance-based Latin Hypercube Sampling Design (LHD) is used to increase the number of the sample points and to evenly spread them in the design space. Multivariate Adaptive Regression Splines (MARS) and Gaussian Stochastic Kriging (GSK) models are employed to capture nonlinear relationship among the design variables. The proposed approach is illustrated with examples.
On the Numerical Solutions of Nonlinear Machine-Tool Chatter With Multiple Delays
Authors: Fofana M. S. , Ryba Pamela B. 
Published: November 2021

Abstract
Stable and unstable machining during chatter and the occurring nonlinear phenomenon have been identified numerically. The corresponding governing equations for the machining model are nonlinear differential equations with multiple time delays. A characteristic equation for the linearized stability about equilibrium machining is analyzed. From this it is readily seen that stable machining increases as the feed rate factor increases. The change in character of nonlinear chatter is viewed as a phase portrait trajectory in a phase plane.
Automatic Defects Measurement on Silicon Wafer Surface by Laser Scattered Defect Pattern
Authors: Takahashi Satoru , Miyoshi Takashi , Takaya Yasuhiro 
Published: November 2021

Abstract
A new optical measurement method for evaluating the defects on silicon wafer surfaces quantitatively, applicable to in-process measurement, is presented. The experimental system for measuring the defects consists of a Fourier transform optical system using a high-power objective lens. In order to verify the feasibility of the applications of this method to automatic in-process measurement, a two-stage measurement for detecting and evaluating small particles, which are typical defects on silicon wafer surfaces, was carried out. The results showed that the proposed two-stage measurement method is effective for measuring small defects in the sub-micro meter scale size.