bluuebunny/crossref_metadata_2025_split huggingface dataset:
Concurrently Engineered Active Composite Sandwich Panels
Authors: Koudela K. L. , Koopmann G. H. , Chen W. 
Published: July 2023

Abstract
The objective of this study was to design, fabricate, and test an active panel capable of significantly reducing the radiated sound power from a vibrating structure. To accomplish this objective, a cascaded flextensional actuator was embedded in a composite sandwich panel consisting of inner and outer E-glass/epoxy face sheets separated by a foam core where portions of the core were removed to accept a high performance actuator. The actuator consisted of a cascaded flextensional, mechanical amplifier driven by two, co-fired, multi-layered, piezoceramic stacks. The stack displacements were amplified by the cascaded flextensional to generate the levels of surface normal vibrations of the panel’s composite face sheets to produce the desired sound power reductions. A prototype active composite sandwich panel containing a single embedded cascaded flextensional actuator was fabricated and an experiment was conducted to evaluate its dynamic response. Dynamic finite element analyses were performed to simulate the experiment. Good correlation was obtained between the predictions and the experimental results. Final testing was conducted in air in a sound transmission loss facility to determine the levels of sound pressure reduction achievable with the prototype active composite sandwich panel. Up to a 25 dB reduction in sound pressure level was obtained over the frequency band of interest.
Electronic Hybrid Limiter (EHL) for Pump Displacement
Authors: Paoluzzi R. , Zarotti L. G. , Ruggeri M. , Fantuzzi C. 
Published: July 2023

Abstract
The paper reports upon numerical simulation tests carried out on a variable displacement axial piston pump equipped with multiple automatic controls. The swashplate control circuit includes two classical hydraulic stages with two tandem three way valves (the pressure compensator and the flow limiter) and a servovalve with digital control circuit acting as a hybrid torque or/and speed limiter. The dynamic response of the system is evaluated for both separate and combined control functions. The effect of changes in the digital control circuit is discussed with reference to the system response to various load demands with special emphasis devoted to the benefits induced by the use of fuzzy control logic.
A Survey of Hydraulic Fluid Analysis Methods
Authors: Norvelle F. Don 
Published: July 2023

Abstract
This paper is intended to provide the reader with a brief overview of the types of analyses that can be used to determine the condition of hydraulic fluids. Several types of contamination are discussed along with their effects on the system and components. Methods of detecting these contaminants are then presented. Finally, recommendations are presented for establishing a fluid analysis program. An appendix is included which lists standards and specifications dealing with hydraulic fluid condition analyses.
An Assessment of Simplified Inelastic Analysis Rules of the ASME Code
Authors: Chattopadhyay Somnath 
Published: July 2023

Abstract
The ASME Code specifies rules on low cycle fatigue evaluation for pressure vessels using elastic analyses. In low cycle fatigue, inelastic strains predominate and a knowledge of variation in strain is essential. However, a detailed inelastic analysis can be prohibitively expensive. Therefore the Code recommends performing linear elastic analyses using either modified material property or introducing a correction factor to account for plastic strain intensification. NB 3227.6 of the ASME Code specifies the use of a modified Poisson’s ratio in an elastic analysis for evaluating local thermal stresses when the maximum stress exceeds the yield strength of a material. NB 3228.3 of the ASME Code prescribes the Ke factor to be multiplied to the alternating stress for entering the design fatigue curve. Both these rules have been critically appraised and some possible improvements recommended.
Inelastic Analysis and Design Based on the p-Version of the Finite Element Method
Authors: Szabo Barna A. , Actis Ricardo L. 
Published: July 2023

Abstract
Until very recently, computer codes offering nonlinear capabilities were based on the h-version of the finite element method. In this paper we describe an algorithm and its implementation based on the p-version of the finite element method. The functionalities to be discussed are inelastic material behavior based on the deformation theory of plasticity and large displacements based on the Almansi strain - Cauchy stress formulation. The nonlinear computations are natural extensions of the linear analysis. In fact, linear analyses are viewed as the first step in performing numerical simulations of real physical systems only. The nonlinear computations are needed for controlling modelling errors. Concurrent control of discretization and modelling errors is described and illustrated by an example.
Development of a Generator Within a Bearing to Provide On-Board Power for Freight Cars
Authors: Samy Ram P. , Fuquen R. , French Michael L. , Varonis Orestes J. , Vuksta Ronald J. , Williams Samuel R. 
Published: July 2023

Abstract
The development of electronically controlled pneumatic (ECP) brake systems for freight trains assumes availability of on-board power. This paper describes recent efforts at The Timken Company to answer the question: “Is it possible to develop an electric generator that fits inside a railroad journal roller bearing and generates adequate power to charge an onboard battery in a freight train car?” Three-phase and single-phase permanent magnet generators were designed and developed to answer this important question and were tested successfully at Timken Research, Canton, Ohio. Some design challenges and test results are presented here. In addition to generating power, these devices can also provide information on the rotational speed (rpm) of the axle.
Simulation Test on Tread Shelling of Railroad Wheel
Authors: Sakamoto Haruo , Hirakawa Kenji , Toyama Kazuo , Nishimura Seiichi 
Published: July 2023

Abstract
Damages generated on railroad wheel tread are wear of tread and flange, heat and thermal cracks, spalling, and shelling. These damages are strongly affected by contact fatigue caused by contact rolling between wheel and rail. However, some of them are thermally influenced by skidding or tread braking. Such a thermal effect produces a variety of tread damages, and is a characteristic of damages due to contact fatigue in wheels.
To prevent such damages, it should be required to clarify the mechanism of damage occurrence or to test and reproduce the tread damages in laboratory. For investigation of new wheel or rail material to avoid such damages, laboratory tests creating the tread damages as appeared in service will be also desired.
In this report, simulation tests using the wheel testing machine and the contact fatigue tester in Sumitomo Metal Industries Ltd. are introduced to show how the tests make the damages on wheel tread and test specimen. In the simulation tests, reproduction of tread shelling has been focused on. This study also paid attention to the role of shear stress on contact fatigue, and the maximum depth of contact shear stress is compared for the tests performed.
Flexible Composite Tubulars
Authors: Walsh Thomas J. 
Published: July 2023

Abstract
Flexibility requirements for long length tubes (1000–10,000 meters) are driven not only by in-service environments, but also restrictions on the outer dimensions of a package destined for transport. Long lengths of tube are required to be spooled onto reels with small inner diameters. The ratio of tube outer diameter to the spooling diameter provides an estimate of the flexure strain. For example, a 50 mm OD tube spooled onto a 1 meter ID reel would impose 5% strain in the tube during storage. In extreme oilfield downhole environments, the flexible tube must not only survive the required extension, but also resist chemical attacks at elevated temperatures while maintaining pressure gradients across the tube wall and sustaining tensile loads.
Plane-Strain Near-Tip Fields for Wedge-Shaped Notches in Pressure-Sensitive Drucker-Prager Materials
Authors: Al-Abduljabbar A. , Pan J. 
Published: July 2023

Abstract
Plane-strain stress and slip-line fields near the sharp and round tips of wedge-shaped notches in perfectly plastic pressure-sensitive materials are investigated. The Drucker-Prager yield criterion is adopted to describe the material yielding behavior. Notch-tip stress and slip-line fields are first established for a sharp notch. Then the notch-tip stress and slip-line fields for a round notch tip are obtained. The results indicate that as the wedge angle increases, the opening stress and hydrostatic tension ahead of the tip of the sharp notch decrease. Also, as the wedge angle increases, the extent of the exponential spiral zone ahead of the round notch tip decreases and, consequently, the maximum opening stress and hydrostatic tension ahead of the tip decrease.
Tridimensional FE-Analysis of Stable Crack Growth in a CT-Specimen of a Structural Steel
Authors: Kolednik O. , Shan G. X. , Yan W.-Y. , Fischer F. D. 
Published: July 2023

Abstract
The crack growth in a plain sided Compact Tension specimen made of an annealed mild steel is simulated by a new tridimensional (3D) Finite Element analysis. The crack extension (Δa) is controlled by local Δa vs. load line displacement (vLL) curves originating from a multi-specimen JIC-test. The results of the 3D-analysis fit excellently to the measured load (P) vs. displacement and J-integral (J) vs. Δa-curves. It is shown that the local crack tip opening displacement at the advancing tip, CTOD, reaches a steady state value after a short transition region.
Further, a modified version of a two layer model (TLM), which was used in previous studies, is introduced. The TLM replaces the expensive 3D-analysis by two 2D-analyses, a plane strain analysis for the midsection region and a plane stress analysis for the near side surface region. The modified TLM uses two local Δa vs. vLL curves (for the midsection and the side surface) to control the crack extension in the two layers. The P-vLL- and J-Δa-curves of the modified TLM come very close to the results of the 3D-analysis.
An Integrated Research Approach to Attack Engine HCF Problem
Authors: Chang Jim C. I. 
Published: July 2023

Abstract
High Cycle Fatigue (HCF) has been the latest safety, operational and maintenance problem facing the jet engine community. HCF is caused by off-design operations of high performance aircraft having higher mean stresses on engine components from higher thrust design. The uncharacterized high cycle, low amplitude vibration from unknown unsteady fluid flow induced loading further complicated the stress and strain prediction on the engine components. The conventional fracture mechanics design approach has failed to quantify the HCF failure. The goal of this paper is to give a quantitative evaluation of the HCF problems, causes and research focuses.
Open-Hole Tension Fatigue Behavior of a Graphite/Bismaleimide at Elevated Temperatures
Authors: Gates Thomas. S. , Johnston William M. 
Published: July 2023

Abstract
This investigation utilizes the open hole tension (OHT) specimen loaded in tension-tension fatigue under isothermal, fixed frequency conditions. A range of load levels and temperature levels where chosen to assess performance. These loads and temperatures ranged from relatively benign conditions (low stress, room temperature) up through aggressive conditions (high stress, high temperature). Measurements were made on stiffness, damage accumulation, remaining strength, and changes in weight, and glass transition temperature (Tg).
Results from this work will help explain the roles of aging, load and fatigue in the performance of elevated temperature OHT as well as providing insights to the individual and synergistic contributions of each process. Experimental apparatus, test and data reduction procedures are outlined and explained.
Thermal Stresses in Unidirectional and Cross-Ply Composite Laminates: A 3-D Micromechanical Investigation
Authors: Dix Brian E. , Saigal Anil , Greif Robert 
Published: July 2023

Abstract
A micromechanical finite element model (FEM) has been developed using ANSYS to investigate the effects of temperature and cross-ply stacking on failure of graphite fiber-reinforced epoxy matrix (P75 graphite/934 epoxy) composites. Thermal residual stresses develop as a result of the difference in the coefficients of thermal expansion of the fiber and the matrix, and the operating and stress-free or cure temperature. It has been shown that these thermal stresses can be large enough to cause matrix cracking and possibly even laminate failure. Results from the 3-D micromechanical FEM are compared to those of the 2-D work, using laminated plate theory, done by Bowles and Griffin. A new curve of ultimate radial stress as a function of temperature was also developed. Using this curve, it is shown that the [0]s laminate model does not cross the failure criterion line when subjected to a delta temperature of −500°F. The [0/0/90/90]s model, however, reaches the ultimate radial stress at a temperature of about −15°F, assuming a stress-free temperature of 350°F. Bowles and Griffin’s ultimate radial stress curve, based on a single radial peaking factor, predicted the matrix failure at about 32°F. Further investigation of the model examines the effect of thermal loading on the matrix cracking.
A Comparison of the Timoshenko Theory and the Euler-Bernoulli Theory for Control of Laminated Beams
Authors: Aldraihem Osama J. , Wetherhold Robert C. , Singh Tarunraj 
Published: July 2023

Abstract
In this paper, the governing equations and boundary conditions of laminated beam smart structures are presented. Sensor and actuator layers are included in the beam so as to facilitate vibration supression. Two mathematical models are presented: the shear-deformable (Timoshenko) model and the shear-indeformable (Euler-Bernoulli) model. The differential equations for a continuous beam are approximated by utilizing finite element techniques for both models. A cantilever laminated beam with and without a tip mass is investigated to assess the validity and the accuracy of the two models when used for vibration supression. Comparison between the two models is presented to show the advantages and the limitations of each of the models. Since the Timoshenko beam theory is higher order than the Euler-Bernoulli theory, it is known to be superior in predicting the transient response of the beam. The superiority of the Timoshenko model is more pronounced for beams with a low aspect ratio. It is shown that use of an Euler-Bernoulli model to represent beam dynamics can lead to the design of an unstable controller.
Control of the Yarn Slip Interlace Deflector for a Textile Machine
Authors: Hunt Richard. M. , Beale David. G. , Nelms R. Mark. 
Published: July 2023

Abstract
As part of an industrial textile machine project, electrically controllable deflectors were needed for a yarn slip interlace device. The control system for the deflector needs to be robust and efficient to lower energy consumption and save space. A presentation of a simplified control system using solenoids with mechanical linkages along with details of the solenoid model is included.
Motion Control of a Space Tether at its Retrieval Phase
Authors: Natori M. C. , Iwasa Takashi , Higuchi Ken , Abe Masato 
Published: July 2023

Abstract
A linearized equation of tether motion is introduced by assuming the exponential change of tether length with respect to time and by adding small control deviation to the basic tether length, and the motion control by using optimum regulator is carried out. Some simulation results show very good control efforts. This control strategy is also applied to simulate the motion of a tethered mass on a special experimental equipment on ground, and successful motion control is demonstrated.
Optimal Control of a Two-Link Flexible Manipulator Along Specified Path
Authors: Farid M. , Lukasiewicz S. A. 
Published: July 2023

Abstract
In this paper a technique is proposed to find near time-optimal control solution of a two-link manipulator with torque and path constraints. Both links and joints are assumed to be flexible. The proposed approach is based on transforming the optimal control problem into an equivalent unconstrained optimum design problem using penalty function methods. Since in flexible manipulators the point for which the prescribed motion is specified and the application points of control torques are connected by elastic bodies, their inverse dynamics is non-causal. The proposed algorithm takes into account the non-causality of such systems via considering pre-actuation and post-actuation in the solution procedure.
Experimental Study of a Hydraulically-Amplified, High Displacement, Induced-Strain Actuators, Proof of Concept Demonstrator
Authors: Rusovici Razvan , Giurgiutiu Victor , Rogers Craig A. 
Published: July 2023

Abstract
A rotor blade trailing edge flap actuation device, HAHDIS (Hydraulically-Amplifed, High-Displacement, Induced-Strain Actuator), driven by two high-displacement induced-strain actuators (ISA), has been built and tested at the Center for Intelligent Materials Systems and Structures. The input displacements of the two solid-state piezoceramic ISA are hydraulically amplified and the linear output displacement is transformed, through a kinematic linkage, into the angular deflection of an aircraft servo-tab.
The paper presents the experimental tests and results. The data collected was processed to yield the electrical input energy and mechanical output energy as well as the displacement frequency response of the tab, over the 1–30 Hz frequency range. Good output force, work and displacement frequency responses were recorded over the frequency range of interest. Limitations in the electrical power supply capabilities were identified to be causing response losses at higher driving frequencies.
Coatings for Boundary Layer Control
Authors: Voropaev Gennady A. , Rozumniuk Natalya V. , May Carol L. 
Published: July 2023

Abstract
This study reviews research on boundary layer control coatings conducted initially by Dr. Gennady Voropaev and his team at the Institute of Hydromechanics, Kiev, and later in cooperation with Cortana Corporation, under the support of the Advanced Research Projects Agency. This article principally reviews findings associated with active control, but we summarize results for passive coatings in order to provide appropriate background. We document the existence of two mechanisms for drag reduction of an oscillating surface – 1.) a dynamic mechanism which is related to energy flux to or from the surface; and 2.) a kinematic mechanism which is related to Reynolds stresses. With an isotropic viscoelastic surface, where the phase of the surface disturbance is fixed at approximately π/2, drag reduction can occur only through the dynamic mechanism. However, in the case of an actively oscillating surface, where factors such as the amplitude of longitudinal and normal surface displacements, the phase difference, ϕ, the phase velocity, and the phase relationships between the surface and the external disturbance can be controlled, it is possible to determine conditions where both dynamic and kinematic mechanisms are operational and optimum, thus leading to a more significant reduction of friction drag.
Micro-Cavity Fiber Optic Sensors Embedded Into Laminated Composites for Impact and Impact-Induced Damage Detection
Authors: Chang Chia-Chen , Sirkis Jim 
Published: July 2023

Abstract
This paper describes the use of fiber optic sensors embedded into laminated [902/04/OF(0)/04/902] graphite /epoxy composites for low velocity impact detection and impact-induced damage assessment (The OF(0) denotes an optical fiber orientation of zero degree). The sensor system uses in-line fiber etalon (ILFE) sensors interrogated with path-matched differential interferometry (PMDI) and demodulated with a “single channel phase tracker”.
Initial impact tests comparing surface-mounted ILFE and resistance strain gages using an aluminum plate were favorable. The ILFE sensors were then embedded at the mid-plane of [902/04/OF(0)/04/902] composite plate subjected to transverse impact. The ILFE sensor response was compared to a resistance strain gage bonded to the back side of the specimen, comparison of the sensors showed that, as expected, higher transverse loads provided more dominant membrane stresses. An unexpected result of this series of tests was that the sensor embedded in the middle layer had higher survivability than the resistance strain gage bonded to the rear surface of the plate.
In a final series of experiments, copper coated ILFE sensors embedded in composite plates were investigated for their potential as damage sensors. The strain of the metal coated ILFE sensor and the load cell response were used to plot a hysteresis strain-load curve to assess the impact-induced damage. The result shows the ∼1 J impact energy starts to initiate the composite damage, and the hysteresis loop area is approximately proportional to the delamination area evaluated by X-ray radiographs. Finally, a control group of composite specimens without embedded optical fiber sensors was also tested under low velocity impact. X-ray NDE indicates that the embedded ILFE sensor does not alter the structural integrity based on the macro-scale observations.
Criticality-Based Maintenance: Prioritizing Maintenance Activities for Optimum Equipment Reliability
Authors: Ciliberti V. Anthony 
Published: July 2023

Abstract
Criticality-Based Maintenance (CBM) is a prioritized approach to the maintenance of process equipment in the oil, gas, and petrochemical processing industries. CBM equally weighs process and safety issues in establishing criticality, which gives companies a return on investment for mechanical integrity efforts while establishing compliance with governmental regulations. This approach optimizes the effectiveness of mechanical integrity programs by focusing on the most important, or critical equipment items.
CBM uses a criticality ranking process which is very similar to the methodology used in a process hazard analysis study. All process equipment items are evaluated and then each is given a relative value in an overall criticality hierarchy. With all equipment evaluated for criticality, prioritization of maintenance activities begins.
A Basis for Determining Fill Times for Dry Fire Lines in Highway Tunnels
Authors: Harris Kenneth J. 
Published: July 2023

Abstract
This paper provides a theoretical basis for the fill time of a single long pipeline utilizing the Euler equations for fluid flow and developing the differential unsteady flow equations. These equations are then integrated numerically to provide the theoretical fill time for a particular series of conditions.
Theoretical models can only be analyzed for relatively simple systems. Pipeline systems in tunnels are subject to complex geometries including horizontal and vertical curves, varying size lines, multiple feed points, pumps, and multiple flow paths. Many commercial software packages are available to assist in the steady state analysis, i.e. operating conditions, of pipeline networks under these conditions. These same tools can be adapted for unsteady flow conditions, such as line filling, by dividing the one system into a series of systems. A comparison of the fill time estimates using this method shows reasonable correlation to that using an unsteady flow analysis.