bluuebunny/crossref_metadata_2025_split huggingface dataset:
Experimental Study of the Behavior of Certain Connectors in a Vibratory Bowl Feeder
Authors: Rosario Lourdes M. , Hernández-Coronas José D. 
Published: February 2021

Abstract
The design and implementation of vibratory bowl feeders involves the analysis of the behavior of the parts as they are conveyed up the bowl track. This paper presents the results obtained in a series of experiments which study the effect of the vibration amplitude in the feeder on the dynamic orientations of a family of parts. The objective of the study is to investigate how complex parts behave in a vibratory bowl feeder and try to establish a relationship between the orientation of the parts and the vibration amplitude of the bowl feeder. The study consisted of experimenting with four types of connectors that were similar in shape but differ in proportions. By experimenting with a part family, we intend to establish and generalize in the near future a relationship between the tendency of the parts to fall in certain orientations, the amplitude of vibration in the feeder, and geometric features or mass properties. The acquired knowledge could then be incorporated in computer aided design programs, together with existing theory on feeder design, to specify orientation devices and operating parameters in the vibratory bowl feeder.
STEP Pilot Project: Consolidated Schema for Airframe Engineering Analysis
Authors: Liang Jian , Shah Jami J. , Urban Susan D. , Harter Edward , Bluhm Thomas 
Published: February 2021

Abstract
This paper addresses the data modeling aspect of an ongoing research project which is aimed at developing an integrated product data-sharing environment (IPDE) based on the international standard STEP. The data model involves multiple design and analysis applications including: Product Design, Computational Fluid Dynamics Analysis (CFD), Finite Element Analysis (FEA), and feature based manufacturability evaluation. The model makes use of multiple STEP Application Protocols (AP203, 209, 214, 224) and integrated resources from different parts of STEP. Extensions beyond STEP were necessary for CFD analysis, parametric geometry and constraints. The latter were imported from the ENGEN* Data Model and a new STEP-compliant model was created for CFD. The consolidated data model used for a prototype is presented in this paper.
Virtual Reality Sculpture Using Free-Form Surface Deformation
Authors: Furlong Todd J. 
Published: February 2021

Abstract
Free-form deformation allows a user to deform surfaces in an intuitive manner that has been compared to sculpting clay (Sederberg and Parry, 1986). This research investigates the use of this deformation technique to create virtual sculpture in the Iowa State University C2, a CAVE™-like apparatus. Emphasis is on intuitive and direct interaction with a surface in order to mold it into whatever shape the user has in mind. An icon-based menu is provided for changing modes of interaction, and a 3D paint tool allows users to add color to their models. Possible applications of this research include virtual art and conceptual or industrial design.
A Constraint Satisfaction Approach for Multi-Attribute Design Optimization Problems
Authors: D’Ambrosio Joseph , Darr Timothy , Birmingham William 
Published: February 2021

Abstract
In this paper, we describe a multi-attribute domain CSP approach for solving a class of discrete, constrained, optimization problems. The multi-attribute domain CSP formulation provides a compact representation for design problems characterized by multiple, conflicting attributes. Design trade-off information is represented by a multi-attribute value function. Necessary conditions for an optimal solution, defined in terms of the value function, are represented as constraints. This provides a uniform problem-solving approach (constraint satisfaction) for identifying solutions that are both feasible and of high value. We present and characterize a consistency algorithm for this type of CSP.
QFD Models for Research and Development of Future Car
Authors: Tsuda Yasuhisa 
Published: February 2021

Abstract
In succession to Tsuda (1995) in which 2 QFD models were proposed for Concurrent Engineering (CE) development of a complicated product such as an automobile, this report treats a study of QFD models for research and development of a future car. First it is discussed, how to approach a future car concept. As customers can not forecast the future, the market quality requirements do not exist which were the very starting point of the 2 QFD models proposed in Tsuda (1995). Instead, experts must find future quality requirements, which then need to be accepted by customers, together with their backgrounds. These circumstances are considered for modification of the 2 QFD models proposed in Tsuda (1995) into new QFD models. These models will then be compared with a research and development case of a future car which was pushed forward on the same basic concept as these models. This real case aimed at the research of both a future car and the methodology of its research and development. It included not only planning and development of a future car, but also customer researches using this concept car. As a result the 2 new QFD models are proven valid for the research and development of a future car.
Robust Tracking for Uncertain Flexible Structures Using Mixed Time-Optimal and Sliding Mode Control
Authors: Jalili Nader , Olgac Nejat 
Published: February 2021

Abstract
An improvement step in robust control is studied for uncertain (linear or nonlinear) systems. The proposed two-stage control scheme first modifies the original desired trajectory, and then imposes robustness against uncertainties in tracking this modified trajectory. For the trajectory modification stage, a simple scheme is considered : time optimal-rigid body motion (TO). The robustness stage is performed using Sliding Mode Control with Perturbation Estimation (SMCPE), an advanced form of SMC. This routine brings some strong features as demonstrated by examples. A rotating hub with flexible beam attachment is taken as the first example, and an undercontrolled two-mass system with a linear spring as the second. The comparative studies show superior results for the combination of TO-SMCPE over the basic SMCPE. Moreover, this two-stage control exhibits stable and highly advantages performance even for cases where H∞-type of robust control structure is declared unstable by earlier investigations.
Unified Approach of Active Panel Vibration and Flutter Controls Using Piezoelectric Actuation and Iterative Root Locus Method
Authors: Ho Ming T. , Chen Roger R. , Chu Li C. 
Published: February 2021

Abstract
Panel forced-vibration and panel flutter are controlled by using piezoelectric actuation and iterative root locus design method. Although forced-vibration and flutter are essentially two different physical phenomena, their limit-cycle behaviors can both be modeled by a non-linear stiffness driven either by a forcing input or by an aerodynamic load. A nonlinear finite element dynamic model which incorporates these two driving terms has been developed for an aluminum panel with one-sided surface-mounted piezoelectric actuators. The first-order piston theory type relation is used to provide an adequate representation of the supersonic aerodynamic load. Surface strains and their associated strain-rates at various pre-determined locations on the panel are the system outputs for feedback. Input and output filters are used in the control loop in order to avoid aliasing and to minimize effects of noise on unmodeled high frequency modes. The importance of including the filters in the model is also demonstrated. The root locus design method is used iteratively to search for the local optimal output feedback gains either to increase modal damping for the forced-vibration case or to increase critical dynamic pressure for the flutter case. Although the control design is linear, it is shown to work adequately for the numerical simulations using non-linear system model. An experiment is performed to verify the forced-vibration results which serves as an inexpensive way of checking and/or modifying the panel flutter control design before a very expensive wind tunnel testing is arranged.
Spatial Characteristics of Acoustic Boundary Control for Interior Noise Suppression
Authors: Hirsch S. M. , Sun J. Q. 
Published: February 2021

Abstract
Suppressing interior sound radiation in aircraft and automobiles is a important problem. There are two mainstream methods for this problem: active noise cancellation (ANC) and active structural acoustic controls (ASAC). An ANC system often requires a high dimensionality to achieve the level of global noise reduction in a three dimensional volume that ASAC systems with a relatively low dimensionality are capable of, while actuators for structural control systems are power intensive. There are also concerns that structural controls may cause damages to the structure. This paper develops an acoustic boundary actuation method that may retain the advantages of both methods. Steady-state optimal noise control in a rectangular enclosure is studied by using the proposed method. Simulation results are presented to demonstrate the ability of acoustic boundary controls to cancel noise fields due to various sources. A study of the spatial characteristics of the acoustic boundary control as a function of frequency and relative phase of disturbances is also presented. Numerical simulations uncover an interesting phenomenon on the variation of the optimal control vector which may have significant implications to the actuator grouping studies.
Adaptive Noise Cancellation in an Acoustic Duct
Authors: Ben-Amara Foued , Kabamba Pierre T. , Ulsoy A. Galip 
Published: February 2021

Abstract
The problem of adaptive noise cancellation in an acoustic duct is discussed. An adaptive controller design approach based on parametrizing the set of stabilizing controllers using the Youla parametrization and tuning the Youla parameter to achieve regulation is presented. Three controller adaptation algorithms are implemented to solve the noise cancellation problem in an acoustic duct. The experimental results indicate a mixed performance for each of the adaptation algorithms, with good performances observed only in some frequency ranges. The discrepancy between the expected and the observed performances is attributed to unmodeled nonlinearities in the speakers.
Vibration Reduction and Isolation by On-Off Control of Friction Force at Spring Support
Authors: Yamaguchi Hideya , Yashima Masahito , Hirayama Yoshinori 
Published: February 2021

Abstract
This paper presents a new method of on-off control for the spring support to reduce and isolate vibration transmitted to machines or structures. The procedure utilizes the auxiliary spring whose end is designed to control the clamping friction force with the brake mechanism. The clamping friction force is varied according to the switching law that is deduced from the variable structure systems (VSS) control theory taking into account the energy dissipation due to friction. The experiments and numerical simulations confirmed the effectiveness of the proposed method by investigating the transient response and the displacement transmissibility.
Application of Dynamic Vibration Absorbers to Mass Measurement
Authors: Mizuno Takeshi 
Published: February 2021

Abstract
A mass measurement system which uses a dynamic vibration absorber as measuring device is developed. It can measure mass even under weightless conditions like in space stations. In this system, an object to be measured is fixed to a rotating table (rotor) at a distance from the rotational axis. Since it makes the rotor unbalanced, a centrifugal force causes the supporting structure to vibrate during rotation. A dynamic vibration absorber attached to the structure is tuned or controlled to cancel the excitation force. When the structure does not vibrate, the amplitude of motion of the auxiliary mass equals the ratio of the amount of unbalance to the auxiliary mass. Therefore, the mass of the object is determined from the motion of the auxiliary mass. According to the measurement principles, the vibration of the supporting structure must be eliminated. A servocompensator with the performance of automatic frequency tracking is applied to reduce the vibration. Experimental results demonstrate that mass can be measured accurately with the developed measurement system.
Modeling and Feedback Control of Flexible Plate With Focus on the Modes Highly Coupled to Radiation Field
Authors: Ren Mingzhang , Seto Kazuto , Doi Fumio 
Published: February 2021

Abstract
A discretization method based on an inverse modal analysis process is presented for creating a lumped parameter model for actual structure. With the discrete system the standard optimal control law can be formulated in physical state space to design a controller. Furthermore, the method makes it easy to target the vibration modes with prominent sound radiation in control design, that is a simplified consideration of active structural acoustics control. The method is demonstrated and verified by vibration and noise control experiments of a clamped plate. Four highly radiating modes among the first twelve modes of the plate are well controlled by using three sensors and one actuator, based on a 9DOF lumped model of the plate.
High Performance Damping With a Semi-Active Spring
Authors: Bobrow James E. 
Published: February 2021

Abstract
In this paper an approach to vibration suppression is presented that does not use any form of viscous damper. That is, the force generated by the actuator has no velocity dependence. We give three different hardware configurations for an actuator that behaves effectively as a spring with an adjustable unstressed length. By adjusting this unstressed length on-line from feedback, it is possible to obtain fast settling times and superior shock isolation characteristics. At the instants when energy in the actuator is maximized, we discard this energy as heat in the working fluid by opening a low power solenoid valve for a short time interval. This sets the unstressed length of the actuator, or effective spring, to be zero. The total energy in the vibrating structure is therefore decreased at these instants of unstressed length adjustment. Analytical results and simulations are given that demonstrate the performance of our approach.
Actuator Selection for Vibration Control With Control Energy Constraints
Authors: Doki Hitoshi , Hiramoto Kazuhiko , Kaido Jun , Skelton Robert E. 
Published: February 2021

Abstract
This paper deals with a sensor/actuator placement problem in design of active vibration control systems for flexible structures. This problem is formulated as a minimization problem of the total energy which is defined as a sum of a kinetic and strain energy in a controlled structure with a constraint of control effort. The inequality constraint on the variance of the closed-loop control effort is adopted to represent the capacity (dynamic range) of the actuator. Using a design algorithm which iteratively tunes the weighting matrix of the quadratic performance index in the LQG problem, the controller which meets these specifications can be synthesized. The optimal location of the sensor/actuator is determined by calculating the total energy for each candidate under several energy constraints of the control effort. The optimal placement of the sensor/actuator depends on the control energy constraint. Simulations and experiments for a cantilevered beam are conducted. These results of the optimization can be used as a guide to the design of active vibration control system.
Phase Space Interpretation and Stability Analysis of a Self Excited, Friction Damped Turbine Airfoil
Authors: Pesheck E. , Pierre C. 
Published: February 2021

Abstract
The free response motion of a self excited, friction damped, single-degree of freedom, turbine airfoil model is determined utilizing both exact and asymptotic methods. A three-dimensional phase space representation is used to examine the system’s global stability, and to further intuitive understanding of the system dynamics. Conclusions are reached regarding the validity and application of stability predictions through comparison of approximate and exact solutions.
Micro-Scale Simulation of Adhesive Effects During Normal Impact
Authors: Streator Jeffrey L. 
Published: February 2021

Abstract
A numerical simulation is developed to investigate the role of adhesive forces during the normal impact of a rigid body against an elastic surface. The model consists of a rigid, 2D translating body and a surface that is composed of a flexible linear array of particles, coupled to a fixed base via linear springs. Adhesive effects are incorporated in the model by ascribing a Lennard-Jones type interaction potential between the surface and the body. Dynamical equations of motion for the interface are integrated numerically during an impact event. It is found that the coefficient of restitution decreases with increasing interaction strength and decreasing approach velocity. Above a certain interaction strength for given velocity and below a certain velocity for given interaction strength, the body is found not to rebound, but sticks to the surface. The simulation results are found to be in qualitative agreement with the impact model of Dahneke (1973, 1975). Quantitative discrepancies are explained by the effects of surface “plucking.”
The Surface Variational Principle: A Different Perspective for Structural Acoustic Modeling
Authors: Ginsberg J. H. 
Published: February 2021

Abstract
This paper surveys the development and application of the surface variational principle (SVP) governing the acoustic interaction between surface pressure and normal velocity. SVP is analogous to the method of assumed modes for vibration analysis, in that it represents the response in terms of a sequence of basis functions that are globally defined. The system equations governing the series coefficients are obtained by requiring that the value of the variational functional be stationary. In the wavenumber-based version of SVP, the pressure and velocity are represented by dual range Fourier series. A brief description of the steps entailed in formulating the SVP equations and coupling them to the equations for an elastic structure is provided. Then the computational requirements of an SVP analysis relative to conventional boundary element and finite element techniques are discussed. This is followed by an example illustrating the convergence properties of SVP. Another example is used to highlight the physical interpretation of the SVP representation of surface response. The evolution of the present version of SVP is surveyed, along with some of its applications. The paper closes with a brief discussion of possible future applications of the method.
Dynamic Responses of a Cylindrical Shell Subjected to Shock Wave Induced by Underwater Explosion
Authors: Weifang Zhong , Zhongzu Liu 
Published: February 2021

Abstract
The dynamic responses of a finite length cylindrical shell submerged in an infinite, inviscid, irrotational, incompressible fluid and subjected to shock waves induced to underwater explosion due to a spherical charge, are investigated in the view of method of modal superposition. Effects of shock wave pressure and hydrodynamic force are considered in shell equilibrium equations. By expanding distribution function of shock wave pressure into Fourier series and using method of Galerkin, the coupled equations of fluid-structure interaction problem are solved numerically. Finally, displacement re sponse of the shell is obtained.
Mode Localization and Delocalization in Constrained Strings and Beams
Authors: Riedel Chris H. , Tan Chin An 
Published: February 2021

Abstract
The free vibration response of a string and a Euler-Bernoulli beam supported by intermediate elastic constraints is studied and analyzed by the transfer function method. The constrained system consists of three subsystems coupled by constraints imposed at the subsystem interfaces. For both the string and beam systems, curve veering and mode localization are observed in the lower modes when the distance between the elastic constraints is varied. As the mode number increases, the modes of the system become extended indicating that the coupling springs have little effect on the system at higher modes. A wave analysis is employed to further investigate the behavior of the systems at high frequencies. Reflection and transmission coefficients are formulated to show the effects of the constraints on the coupling of the subsystems. The weakly bi-coupled beam produces an interesting phenomena where a particular mode experiences no localization while neighboring modes are localized. The frequency at which this occurs is termed the delocalization frequency. Only one delocalization frequency exists and it occurs where the reflection coefficient of the propagating wave becomes zero.
Interpreting Proper Orthogonal Modes in Vibrations
Authors: Feeny B. F. 
Published: February 2021

Abstract
We investigate the interpretation of proper orthogonal modes (POMs) of displacements in both linear and nonlinear vibrations. The POMs in undamped linear symmetric systems can represent linear natural modes if the mass distribution is known. This is appoximately true in a distributed system if it is discretized uniformly. If a single mode dominates, the dominant POM approximates the dominant mode. This is also true if a distributed system is discretized arbitrarily. Generally, the POMs represent the principal axes of inertia of the data in the coordinate space. For synchronous nonlinear normal modes, the dominant POM represents a best fit of the nonlinear modal curve. Linear and nonlinear simulation examples are presented.
Nonlinear Localization in Systems of Tautochronic Vibration Absorbers
Authors: Chao Chang-Po , Shaw Steven W. 
Published: February 2021

Abstract
The system considered consists of a rigid rotor and N centrifugal pendulum vibration absorbers (CPVAs) riding on epicycloidal paths tuned to order n, the same as the dominant order of the applied torque. An investigation is carried out to determine the effects that a dynamic instability of the synchronous motion of CPVAs has on the system performance. Using various co-ordinate transformations, including a group-theory-based transformation and an angular transformation, the system dynamics are modeled by a set of 2N first-order, averaged, autonomous differential equations. A bifurcation analysis of these equations shows that in the post-bifurcation dynamic, one of the N absorbers moves out of step and at a much larger amplitude than its partners. This localized response is dynamically stable and leads to the worst-case (that is, the smallest) operating torque range of all the possible post-critical steady-state solutions. Analytical estimates of the torque range and the rotor acceleration are derived based on a truncated version of the equations, and more accurate estimates are obtained from a numerical solution of the non-truncated equations. The results are found to be very accurate when compared to numerical simulations.