bluuebunny/crossref_metadata_2025_split huggingface dataset:
Stress Analysis and Strength of Joints Combining Adhesives With Bolts Subjected to Torsions
Authors: Yoneno Masahiro , Sawa Toshiyuki , Nishijima Hidekazu , Matsuo Motohiro 
Published: July 2023

Abstract
The stress distributions in joints combining adhesives with bolts are analyzed by using axisymmetrical theory of elasticity as a three-body contact problem when torsion is applied to the joints. The joints consist of two hollow cylinders and they are fastened by a bolt and nut after being joined with an adhesive. When an external torsion is applied to combination joints, an increment / decrement of torsion occurs in the bolt. A method for estimating the variation of torsion in the bolt is proposed. In addition, using the interface stress distribution, a method for predicting strength of the combination joint is proposed. The torsional load produced in the bolt was measured using strain gauges. Strength of the combination joint was also measured. A fairly good agreement was seen between the analytical and the experimental results. It is shown that the increment of torsional load occurs in the bolt is small. It is found that the strength of the combination joints is greater than that of adhesive joints. It is also seen that the combination joint strength increases as the initial clamping force increases and that it is greater than that of bolted joints without adhesives.
Contact Pressure Distribution in a Key Joint
Authors: Váradi Károly , Verghese D. M. , Engelbrecht S. 
Published: July 2023

Abstract
This paper contains an investigation of the contact pressure distribution in a key joint using the Finite Element Method. The key is mounted using an interference fit, and the torque transmission is increased in steps from 0 to 25, 50, 75, and 100 % of the maximum torque. The obtained pressure distributions show a very pronounced transition of the stress distribution from pure interference fit to almost pure torque transmission. It is also found that the pressure distribution and the number of contact surfaces depends heavily on the initial fit between the shaft and the key.
Applications of Active Noise and Vibration Control in Automotive Vehicles
Authors: Shoureshi Rahmat A. , Gasser Robert , Knurek Thomas , Wheeler Matthew 
Published: July 2023

Abstract
Competitive pressure in improving automotive fuel economy has forced manufacturers to design smaller and lighter vehicles with more and more non-metallic (composite) components. This manufacturing trend has resulted in vehicles with increased levels of noise and vibrations. In parallel, there have been efforts in using different noise control techniques quieting small aircraft. Today, noise and vibration control have become a prime consideration in the general manufacturing industry, and more specifically the aircraft and automotive industries. Increased attention to product quality has brought the issue of “psycho-acoustics” to the transportation industry. Automotive manufacturers believe that noise and vibration levels in a vehicle are measures of quality used by the consumer. Thus within recent years, there has been a major increase of effort in the design of noise and vibration characteristics of vehicles that would better appeal to the occupants. This paper presents some results from our research and development in the area of active/adaptive noise control in transportation systems with specific results from our activities related to aircraft and to automotive vehicles.
Application of Active Noise Control in Corporate Aircraft
Authors: Jackson Philip J. B. , Ross Colin F. 
Published: July 2023

Abstract
Following the successful introduction of Active Noise Control (ANC) systems as standard production fits on commuter aircraft (Saab2000, Saab340B and Dash8Q series 100, 200 & 300), recent efforts have focused on developing low-cost, low-weight systems for smaller corporate aircraft.
This paper describes the approach taken by Ultra to the new technical challenges and the resulting improvements to the design methodology. A review of system performance on corporate (King Air & Twin Commander) turboprop aircraft shows repeatable global Tonal Noise Reductions (TNR’s) of &gt; 8 dBA throughout the whole cabin, achieving reductions &gt; 20 dB in some locations at the blade-pass frequency (BPF), and major comfort benefits throughout the flight envelope with a weight penalty of less than 20 kg.
A “New” Approach to Active Noise Control in Ducts
Authors: Mehta Prashant , Zheng Yuan , Chait Yossi , Hollot C. V. 
Published: July 2023

Abstract
In this paper we consider the fixed-filter design approach for active noise control (ANC) in ducts. Based on a large body of literature during the past decade that deals strictly with adaptive filter solutions (see [1] and references contained therein) the fixed-filter approach appears to be all but discarded for this application. The ANC system under consideration has a similar configuration to those used in most adaptive implementations; i.e., a duct equipped with both feedforward and feedback sensors and a control speaker. Our design of a linear, time-invariant controller involves three steps: (1) system identification from the experimental duct frequency response, (2) H∞ synthesis using the identified plant and model errors, and (3) use of Quantitative Feedback Theory (QFT) to further improve performance by sequential tuning of the feedback and feedforward filters using the experimental data. Preliminary experiments indicate that attenuation levels of 10–30 dB are achievable over a 400 Hz band without amplification in the immediate range. An important consequence of LTI designs is that performance is guaranteed for wideband noise as well as pure tone disturbances — in adaptive schemes stability and performance may be very difficult (if impossible) to guarantee beforehand. This paper focuses on the third step of our three-step approach — the QFT design aspect — (the other two steps are described in [2]).
Experimental Active Vibration Control of Automotive Chain Drive Systems
Authors: Dishan Huang , Fan Q. , Tan C. A. 
Published: July 2023

Abstract
Impact between chain links and sprockets during their engagements is generally considered to be the major source of noise in power transmission chains. To reduce the noise, one approach is to reduce the tension in the chain. However, this would lead to excessive chain vibrations and subsequently reduce the life span and durability of the chain. This paper presents an experimental approach to reduce vibrations of a chain drive system. Experiments were conducted on a test stand which consists of an automotive chain running between two fixed sprockets. The experiment results show that the amplitude of vibration of the chain can be reduced by as much as 90% in the speed range under consideration.
The Impulse Response of Panels
Authors: Reynolds Robert R. 
Published: July 2023

Abstract
The impulse response of a thin, elastic panel is predicted using classical modal analysis and a new asymptotic modal approximation. The asymptotic solution requires much less solution effort than the classical solution. It is shown that the latter also provides a good estimate of the local panel response near the excitation and of the average response away from the excitation for short to moderate times after the input pulse. The method yields excellent predictions of the most important features of the response; the maximum amplitude of the response and its decay behavior. It is expected that this method will provide engineers with a very efficient, method for estimating structural behavior for vibration isolation and control purposes.
On the Energy Dissipation Characterisctics of Active Constrained Layer Damping
Authors: Baz A. 
Published: July 2023

Abstract
The shear strains in the visco-elastic cores of beams controlled by Active Constrained Layer Damping (ACLD) treatments are determined and compared with those of beams controlled by Active Control (AC) and conventional Passive Constrained Layer Damping (PCLD) treatments. Such comparison is essential in quantifying the individual contribution of the active and passive damping components, to the overall damping characteristics, when each operates separately and when both are combined to interact in unison as in the ACLD treatments. The comparisons are based on distributed-parameter models which describe the behavior of beams controlled by ACLD as well as beams treated by AC and PCLD treatments. The distributed-parameter models give closed-form expressions for the energy dissipation characteristics of the ACLD treatments in comparison with those of the AC/PCLD treatments. The results obtained indicate that the ACLD treatments are capable of developing shear deformations, in the visco-elastic cores, higher than those generated by the AC/PCLD treatments when the ratio of the longitudinal rigidity of the constraining layer to that of the base beam is less than 1. With such enhanced shear deformation capabilities, the ACLD treatments can develop high damping and effective attenuation of the vibration of critical structural systems.
On Optimal Placement of Piezoelectric Actuators in Vibration Control of Adaptive Structures
Authors: Gabbert Ulrich , Schulz Ingolf 
Published: July 2023

Abstract
The paper presents an optimality criterion for the placement of actuators in adaptive mechanical structures, which can be formulated independently of the control algorithm and the actuator type. The basic idea is an energetically approach of a dynamic system. Treating a vibration as a periodically transformation between different energy forms, damping demands that the vibration energy must be deleted. In vibration control a part of this energy is transmitted to active or passive damping elements and changed into other energy forms, which do not contribute to the movement of the system. A maximum input of energy into the actuators during the considered time range is expected for optimal vibration control of the system. To ensure the time invariance of the criterion, the results of the simulation (finite element method, Newmark integration scheme) are transformed from the time domain into the frequency domain using the discrete Fourier transformation. The proposed technique of actuator placement is demonstrated at an excited beam structure.
Design of a Piezoelectric Actuator for Active Vibration Control
Authors: Brennan M. J. , Garcia-Bonito J. , Elliott S. J. , David A. , Pinnington R. J. 
Published: July 2023

Abstract
In an active vibration control system there is a requirement for actuators, sensors and an electronic controller. Although there have been significant advances in controller design, in terms of software, hardware and control algorithms, this has not been matched in the design of the transducers. This paper is concerned with the area of actuator design. Novel transducers are described that use piezoelectric devices as the active elements, and are designed to be used as a large displacement vibration actuators over a broad range of frequencies. Because piezoelectric elements are high impedance devices, the designs of the actuators have to incorporate impedance transformers so that the displacement output from the piezoelectric element is amplified significantly and two different ways of achieving this are described.
Uniform Damping and Stiffness Control of Structures With Distributed Actuators
Authors: Washington Gregory , Silverberg Larry 
Published: July 2023

Abstract
The research in this paper introduces an algorithm for uniformly damping and stiffening structures using distributed actuators. Inherent in this algorithm is the ability to eliminate structural biases, which can cause steady state error. The method involves the utilization of modal techniques to calculate the proportional, integral, and derivative gains in a feedback control law. The gains are calculated by first converting the system into the modal domain, second by employing the principles of uniform damping and stiffening to the system in the modal domain, and finally by converting that system back into the physical domain. The beauty of this technique lies in the fact that even though the principles of modal control are used in gain setting, no modal information is needed in the final control law. The theory is validated by simulations and is illustrated in an example. Since a modal approach and distributed actuation is utilized, the benefit to active control and adaptive structures is discussed.
Neural-Network-Based Control of Vibration in the Presence of Uncertainties in System Parameters and Excitation Frequencies
Authors: Wang T.-C. , Sinha A. 
Published: July 2023

Abstract
A neural-network-based algorithm has been developed to control steady state vibration in a flexible structure. The main feature of this algorithm is that neural networks are trained to compensate for uncertainties in system parameters and excitation frequencies. Numerical results are presented to corroborate the validity of this algorithm.
An Optimization Based Technique for Determining Nonlinear Normal Modes
Authors: Slater Joseph C. 
Published: July 2023

Abstract
This paper examines a new approach for determining the nonlinear normal modes of undamped non-gyroscopic multiple degree of freedom systems. The method presented here can be called an optimized Poincare section technique. Algebraic solutions generally assume a solution for nonlinear modes in the form of polynomial expansions. This method makes only the assumption of repetitive motion in numerically determining the mode shapes. The advantage of this approach is that the accuracy obtained in the mode shape identification is a function only of the accuracy of the numerical integration and optimization used and not of the number of terms in the power series representation of the nonlinear mode shape. However, invariance of the modal manifolds cannot be proven using this technique, and mode bifurcations can be easily overlooked.
On-Line Prediction and Optimization of a CVD Barrel Reactor: An Experimental Study
Authors: Mahajan R. L. , Walker K. J. 
Published: July 2023

Abstract
Neural networks offer an attractive technique for process modeling and optimization. Once trained, these models tend to be very fast and can be easily updated. In this paper, we exploit these desirable properties of neural networks and demonstrate that these models can be incorporated, on-line, into a process to provide real-time analysis as well as estimate settings for process optimization. The process selected is a mock-up chemical vapor deposition barrel (CVD) reactor. The temperature distribution on the facets of the susceptor is influenced by the flow imbalance through the two inlet nozzles and their orientations. A statistical design of experiments (DOE) is conducted to relate the input parameters to the output (average temperature and temperature variation) and a neural network model is trained using the DOE points. The model is then embedded in a PC which is also used to control the flow meters monitoring flow entering the barrel reactor through the two nozzles. The temperature readings are fed into a data acquisition system which is interfaced with the PC. It is shown that for given input settings the neural network model predicts the average temperature over the surface of the susceptor facet in less than a fraction of a second. A side by side comparison with the experimental average temperature shows excellent agreement for a wide range of input parameters. A deviation model exhibits similar agreement. The deviation model, in conjunction with a steepest descent algorithm, provided an estimate of optimum settings for minimum deviation.
Liquid Slug Motion in Compliant Piping
Authors: Wiggert D. C. , Hatfield F. J. 
Published: July 2023

Abstract
An approximate method of estimating the displacements and stresses in piping caused by a liquid slug moving in a voided line is presented. The event is caused when the slug experiences a change in momentum and transfers a force at a discrete location in the pipe. The most significant mode of the piping response is treated as a single-degree-of-freedom system that responds to the transient hydrodynamic excitation. Impact factors are generated for several representative hydrodynamic waveforms. An example is presented to demonstrate the methodology.
Three-Dimensional Numerical Analysis of Low Reynolds Number Precessing Jets
Authors: Manohar Shailesh S. , Pauley Laura L. , Kulkarni Anil K. 
Published: July 2023

Abstract
Experimental observations have shown that precessing jets have two distinct flow regimes. At “subcritical” Strouhal numbers, the jet continues to move away from the axis of precession. At “supercritical” Strouhal numbers, the jet bends back towards the axis of precession and eventually appears axisymmetric downstream. The objective of this study is to numerically determine the critical Strouhal number for the transition between the two flow regimes and to observe the nature of a precessing jet. A three-dimensional Navier Stokes solver employing the artificial compressibility method and a four-stage Runge-Kutta scheme has been used. Two Reynolds numbers, 125 and 250 were considered. The precessing jet was found to have a pressure gradient acting across it which caused it to spiral and bend back towards the axis of precession. The critical Strouhal number was independent of the Reynolds number and determined to be ∼ 5 × 10−3. This conclusion compared favorably with experimental observations at high Reynolds numbers.
Parametric Study of Pin Length and Reynolds Number Effects on Heat Transfer in a Cast Pin Fin Coldwall for Electronic Systems
Authors: Short Byron Elliott , Raad Peter E. , Price Donald C. 
Published: July 2023

Abstract
At low to moderate Reynolds numbers, cast pin fin coldwalls provide an excellent combination of performance and low unit cost for air-cooled electronic systems. The purpose of the paper is to study the details of the fluid dynamics in order to better understand the heat transfer performance within the flow regime appropriate for cast pin fin coldwalls.
A parametric study is presented examining the variation in the Nusselt number over a range of pin lengths and Reynolds numbers. The numerical study uses a five-pin cell to simulate an embedded flow pattern within a large array of staggered pin fins. The modeling technique was previously validated using experimental data.
Performance comparisons are made for pin length-to-pin diameter ratios of 2 ≤ L/d ≤ 6 and for 200 ≤ Red ≤ 2000. Conclusions are drawn assessing the effects of the fluid dynamics, such as the horseshoe vortices formed at the pin-wall interface, on the local heat transfer mechanisms. Effects of the pin spacing were addressed by a previous experimental study.
On the Routinization of Analysis for Physical Design
Authors: Peak Russell S. , Scholand Andrew J. , Fulton Robert E. 
Published: July 2023

Abstract
While it is generally agreed physical designers would like to benefit more from analysis, methodologies are lacking for identifying appropriate analysis models and transforming them into readily usable tools. This paper identifies physical designer needs with respect to analysis, and introduces the term “routinization” to describe the process of creating routine analysis modules — automated analysis models that can be regularly used in product design.
A routinization methodology is presented with electronic packaging examples. Based on the multi-representation architecture (MRA), a design-analysis integration strategy, this methodology creates catalogs of product model-based analysis models (PBAMs) — analysis modules that associate design data with specific analysis models to obtain results in a highly automated manner.
The methodology is illustrated using a simple PBAM for PWB warpage analysis. Applications to solder joint fatigue and plated through hole deformation are also highlighted, with solution methods ranging from encoded formulae to multi-vendor 3D finite element analysis. Observations are given, including how routinization aides both electronic packaging researchers and physical designers. While it enables researchers to more readily benefit designers, it also acts as a catalyst for identifying needed research extensions.
Prevention of Overheating and Frequent Thermal Cycling of Outdoor Electronic Cabinets Cooled by Forced Air Convection in Cold Climates
Authors: Zimmerman Eric B. , Hegab Hisham , Colwell Gene T. 
Published: July 2023

Abstract
Telephone companies use electronics to route calls between customers. These electronics are generally packaged together and placed in steel containers located outdoors. When a significant amount of electronics are packaged together the cooling capacity of natural convection is exceeded and supplementary cooling systems are needed. Forced air cooling is generally the system of choice given the relative low cost and simplicity when compared to alternative cooling methods. Simple axial flow fans are typically turned on and off by a thermostat located inside the cabinet to keep the inside air temperature below a predetermined maximum. While the behavior of an electronics cabinet with this type of cooling system may be acceptable under conditions of a summer day in the desert southwest, it may overheat or have unacceptable thermal cycling during the cold days of winter. Numerical simulation using a system of lumped thermal capacitances is used to predict the air-flow rate which would prevent thermal cycling and reduce operating temperatures to well below that found in the summer months.
Dynamic Analysis of the Lightweight Mission Specialist Seats for the Space Shuttle Orbiter
Authors: Jermstad Wayne A. 
Published: July 2023

Abstract
The Orbiter Lightweight Seat - Mission Specialist (LWS-MS) is designed to replace the existing mission specialist seats in the space shuttle orbiter. The goal of the LWS-MS project is to reduce the weight of each seat by 50%, while increasing crashworthiness. The development of typical aircraft seats relies heavily on dynamic crash testing. The LWS-MS team at the NASA Johnson Space Center (JSC) reduced the amount of dynamic testing required by performing dynamic analysis of the seat and occupant.
The analysis uses the Dynamic Analysis and Design Software (DADS) package by Computer Aided Design Software, Inc. Custom code was added to model the seat restraint system, and to model contact between the occupant and the seat. The occupant is modeled as a group of rigid bodies. The seat is represented by its mass and stiffness matrices and by its normal modes. The DADS model shows good correlation with test data for both low and high level input tests.
Linear Visco-Elastic Material Model for Headform Skin With Applications to Interior Head Impact Protection
Authors: Faruque M. O. , Liu N. , Chou C. C. 
Published: July 2023

Abstract
Vinyl rubber dummy skin used in the deformable featureless head form exhibits rate sensitivity. This rate sensitivity seems to play a significant role in the interior head impact evaluation. In order to characterize the rate dependency of dummy skin, a linear visco-elastic material law is developed in FCRASH. To validate this model, a number of hcadform drop tests and interior head impact events are simulated using FCRASH and results are compared with the test data. Evidently excellent agreement is achieved between the analyses and the test data.