bluuebunny/crossref_metadata_2025_split huggingface dataset:
Analysis of Impact Noise of Nail Ejection in Wire Nail Machines
Authors: Ding Jack , Al-Jumaily Ahmed , Wilson Doug 
Published: February 2021

Abstract
A wire nail production machine can be classified as one of the punch press machines. By nature, the production of wire nails involves the development of a series of force impulses which in turn generate various sound pressure levels with different frequencies. Typically, the machine operations generating impact noise include pressing, cutting, ejecting, wire gripping and feeding. The punch pressing is the movement of punch header to press forming the nail head. It produces a large force impulse which in turn generates a high level of impact noise and consequently high levels of ancillary impact noise such as the impact noise by the backlashes. It has been found that this type of impact noise is not necessarily the most annoying one. The impact noise generated by nail ejection, however, has been identified as one of the annoying noise components. The ejector used in a nail machine for executing the movement of nail ejection produces ringing noise at high frequencies when it is struck by the punch header in each cycle of the machine operations. This paper presents the analyses of and experiments on the ejection force impulse and the characteristics of the impact noise generated by nail ejection.
The Geometrical Mode Analysis of a Vibrating System With the Planes of Symmetry
Authors: Dan Byung Ju , Choi Yong Je 
Published: February 2021

Abstract
Vibration modes obtained from a modal analysis can be better explained from a screw theoretical standpoint. A vibration mode can be geometrically interpreted as a pure rotation about the vibration center in a plane and as a twisting motion on a screw in a three dimensional space. This paper presents a method to diagonalize a spatial stiffness matrix by use of a parallel axis congruence transformation when the stiffness matrix satisfies some conditions. It also describes that the diagonalized stiffness matrix can have the planes of symmetry depending on the location of the center of elasticity. For a system with the planes of symmetry, the vibration modes can be expressed by the axes of vibration. Analytical solutions for the axes of vibration have been derived. A numerical example of an application to the vibration analysis of an optical disc drive has been presented.
Rotational Shock Performance and Actuator Resonant Delatch Capability of a Computer Hard Disk Drive With Magnetic Cup Latch
Authors: Lin Chen-Chi , Casey Shawn , Wang David , Oveyssi Kamran , Edwards John 
Published: February 2021

Abstract
This paper presents the analytical and experimental studies of the rotational shock performance and actuator resonant delatch capability of a computer hard disk drive with magnetic cup latch. Higher stiffness of the latch board and stronger magnet retention force give better rotational shock performance but degrade the actuator resonant delatch capability. Optimizing the system stiffness and magnet strength is the key to meet both shock and delatch requirements. The effects of the shock pulse width on the shock performance and the numbers of resonant cycles on the delatch process are also investigated.
Dynamic Modeling and its Solving Method of Elastic Foundation for Dynamic Machine
Authors: Liao Dao-Xun , Huang Xiao-Cheng , Lu Yong-Zhong , Jin Wei-Jun 
Published: February 2021

Abstract
Engineering practices indicate that the soil as foundation has great effect on base vibration. In this paper, Vlasov model is applied to base-foundation (soil) system of dynamic machine. According to the elasticity theory and soil dynamics, the kinetic energy and potential of foundation can be derived. Based on the Hamilton’s variational principle, we are able to establish multivariable fonctionelle equation and Euler’s equations of foundation. Consequently, we can obtain the partial differential equation of free vibration for the foundation on condition that the damping of the system is neglected, which equations are different from the existing references. It is very difficult to solve the complicate differential equations. This paper proposes a new solving method that has great improvement for existing literatures. It provides theoretic basis of the dynamic modeling and dynamic characteristic analysis of bas-foundation system for dynamic machine.
Solution of the Moving Mass Problem Using Complex Eigenfunction Expansions
Authors: Lee Keh-Yang , Renshaw Anthony A. 
Published: February 2021

Abstract
A new solution technique is developed for solving the moving mass problem for nonconservalive, linear, distributed parameter systems using complex eigenfunction expansions. Traditional Galerkin analysis of this problem using complex eigenfunctions fails in the limit of large numbers of terms because complex eigenfunctions are not linearly independent. This linear dependence problem is circumvented in the method proposed here by applying a modal constraint on the velocity of the distributed parameter system (Renshaw, 1997). This constraint is valid for all complete sets of eigenfunctions but must be applied with care for finite dimensional approximations of concentrated loads such as found in the moving mass problem. A set of real differential ordinary equations in time are derived which require exactly as much work to solve as Galerkin’s method with a set of real, linearly independent trial functions. Results indicate that the proposed method is competitive with traditional Galerkin’s method in terms of speed, accuracy and convergence.
Stability of Out-of-Plane Vibration of a Uniform Beam Carrying an End Body and Attached Radially to a Rotating Hub
Authors: Naguleswaran S. 
Published: February 2021

Abstract
This paper reports an analytical study on the out-of-plane vibration and stability of a uniform beam attached to a rotating hub and carrying a rigid body at the other end. The parameters which govern the natural frequencies are the hub radius (root offset), speed of rotation of hub, the mass of the end body, its moment of inertia about an axis in the plane of rotation and through the centre of mass, the radial offset of the centre of mass from the beam end It is shown that for certain combinations of the system parameters a ‘tuned’ state (analogous to whirling of a shaft) is possible. It is also shown (hat for some combinations a natural frequency is zero (borderline of instability) even though the axial force distribution in the beam is tensile throughout. Negative centre of mass offset is a necessary but not sufficient condition for zero frequency to occur.
Modal Analysis of Ballooning Strings With Small Sag
Authors: Fan Rongjun , Singh Sushil K. , Rahn Christopher D. 
Published: February 2021

Abstract
During the manufacture and transport of textile products, yarns are rotated at high speed and form balloons. The dynamic response of the balloon to varying rotation speed, boundary excitation, and disturbance forces governs the quality of the associated process. Resonance, in particular, can cause large tension variations that reduce product quality and may cause yarn breakage. In this paper, the natural frequencies and mode shapes of a single loop balloon are calculated to predict resonance. The three dimensional nonlinear equations of motion are simplified via small steady state displacement (sag) and vibration assumptions. Axial vibration is assumed to propagate instantaneously or in a quasistatic manner. Galerkin’s method is used to calculate the mode shapes and natural frequencies of the linearized equations. Experimental measurements of the steady state balloon shape and the first two natural frequencies and mode shapes are compared with theoretical predictions.
Fundamental Frequencies of Cantilever Beams
Authors: Hoffmann Jon A. , Wertheimer Todd 
Published: February 2021

Abstract
A simple relationship which predicts the first mode natural frequency of a tapered cantilever beam is presented as a function of the stiffness to mass ratio and a mass distribution parameter for the beam. In this study the mass distribution parameter, obtained using referenced results, is presented as a function of the taper ratio of the beam for the case of beams with linear tapers. Conical truncated beams, truncated wedges with vibration perpendicular to the parallel sides of the taper, and truncated wedges with vibration parallel to the parallel sides of the taper have been investigated.
Proper Orthogonal Decomposition of an Experimental Cantilever Beam
Authors: Riaz M. S. , Feeny B. F. 
Published: February 2021

Abstract
We apply proper orthogonal decomposition (POD) to an experimental cantilevered beam and obtain a set of proper orthogonal modes (POMs) and proper orthogonal values (POVs). The POMs form a bases that represents the optimal distribution of energy in the system. A set of experiments was performed excited by impulse inputs and sensed with strain gages. The strains were converted to displacements and POD was performed on the displacements. The POMs were compared with the theoretical normal modes. The results confirmed the validity of this method for acquiring lower modes of vibration. The identification of lower modes was robust with respect to the choice of data acquisition parameters and input locations. We also used different types of basis functions for converting strains to displacements.
The Sliding of an Elastic Half-Space Against a Rigid Surface With Friction Reduction due to Incident Dilatational Waves
Authors: Adams George G. 
Published: February 2021

Abstract
The steady sliding of a flat homogeneous and isotropic elastic half-space against a flat rigid surface, under the influence of incident plane dilatational waves, is investigated. The interfacial coefficient of friction is constant with no distinction between static and kinetic friction. It is shown here that the reflection of a harmonic wave under steady sliding consists of a pair of body waves (a plane dilatational wave and a plane shear wave) radiated from the sliding interface. Each wave propagates at a different angle such that the trace velocities along the interface are equal and supersonic. The angles of wave propagation are determined by the angle of the incident wave, by the Poisson’s ratio, and by the coefficient of friction. The amplitude of the incident waves is subject only to the restriction that the perturbations in interface contact pressure and tangential velocity satisfy the inequality constraints for unilateral sliding contact.
It is also found that an incident rectangular wave can allow for relative sliding motion of the two bodies with a ratio of remote shear to normal stress which is less than the coefficient of friction. Thus the apparent coefficient of friction is less than the interface coefficient of friction. This reduction in friction is due to periodic stick zones which propagate supersonically along the interface. Under appropriate conditions, the bodies can move tangentially with respect to each other in the absence of an applied shear stress. The influences of the angle, amplitude, and shape of the incident rectangular wave, the interfacial friction coefficient, the sliding speed, and of the remotely applied normal stress, on friction reduction are determined.
Dynamic Response of Adhesively Bonded Beams Subjected to Harmonic Peeling Loads
Authors: Hamidzadeh H. R. , Prescher J. L. , Nayeb-Hashemi H. 
Published: February 2021

Abstract
The only viable method to join some components is by using adhesive. These components are often subjected to dynamic loading, which may cause initiation and propagation of failure in the joint. In order to insure the reliability of these structures, their dynamic response and factors affecting their response must be understood.
Dynamic response of a single lap joint subjected to an out of plane harmonic force is evaluated. The bonded joint is modeled as Euler Bernoulli beams joined with an adhesive and constrained at one end and subjected to a harmonic force at the free end. The results show that the system response is not sensitive to the damping characteristic of the adhesive. In contrast, the elastic properties, and geometry of adhesive and adherends dominate the response. Significant peel and shear stresses develop in the over lap. These stresses are confined to the edge of the overlap and their magnitude increases as the frequency approaches the natural frequency of the system. The results show that the direction of the shear stress changes as the frequency of applied load sweeps over the first natural frequency. In contrast the peeling stress direction does not change as result of sweeping frequency over the first natural frequency.
Effect of Localized Heat Damage on the Natural Frequency of Glass-Fiber Reinforced Plastics
Authors: Nayeb-Hashemi H. , Harrison A. , Kisnomo P. , Saniei N. 
Published: February 2021

Abstract
The effect of localized heat damage on the first natural frequency of fiber glass reinforced plastic is studied. The study is performed to determine the possibility of using natural frequency to evaluate the damage state of a composite. The natural frequency and its variation with the damage (size, location, and severity) are obtained using finite element analyses, continuum and lumped models. The results show that the natural frequency of composite specimen decreases with the growth of the damage size and increase of damage severity. However, its variation is much more sensitive to the damage size and location than to its severity. The natural frequency apparently does not change significantly with the number of damage spots as long as the total damage area is constant. A correlation between the natural frequency and the residual tensile strength of the composite is obtained, indicating its potential in predicting the residual strength of damaged composites.
Free Vibration of Uniform, Flexible, Cylindrical Shell Rotors
Authors: Wang Fei-Yue , Luo Albert C. J. 
Published: February 2021

Abstract
The critical speeds and responses of uniform, flexible, cylindrical rotors are predicted by use of the Riccati transfer matrix method. The critical speeds are also measured experimentally. The computational and experimental results are in good agreement. The balancing of two cylindrical shell rotors is completed. For the two balanced rotors, no large amplitude vibration occur when the operating, rotational speed passes through critical speeds, and that rotation speed can arrive to a very high value to meet the requirement of isotope separation in engineering.
Influence of Warping Effects on the Dynamic Behavior of Composite Beams Under Bending and Torsion Combined Loads
Authors: Tanghe-Carrier Frédérique , Gay Daniel 
Published: February 2021

Abstract
The dynamic behavior of composite beams under both bending and torsion combined loads is sought with a 1-D approach based on the integral parameter method. The developed theory takes into account side effects due to the deformation of the cross-section out of its plane. In case of beams with a center of symmetry, the effects of bending and torsion are uncoupled. For such beams we evaluate the eigenfrequencies of bending and torsion with non-uniform warping. The present theory is finally implemented through the study of an isotropic sandwich beam: we compare its bending and torsion theoretical eigenfrequencies with FEM and experimental results.
Transfer of Energy From High- to Low-Frequency Modes in the Bending-Torsion Oscillation of Cantilever Beams
Authors: Arafat Haider N. , Nayfeh Ali H. 
Published: February 2021

Abstract
We investigate the nonlinear bending-torsion response of a cantilever beam to a transverse harmonic excitation, where the forcing frequency is near the natural frequency of the first torsional mode. We analyze the case where the first in-plane bending mode is activated by a nonresonant mechanism. We use the method of time-averaged Lagrangian and virtual work to determine the equations governing the modulations of the phases and amplitudes of the interacting modes. These equations are then used to investigate the nonlinear behavior of limit-cycle oscillations of the beam as the excitation amplitude is slowly varied. As an example, we consider the response of an aluminum beam for which the natural frequency of the first in-plane bending mode is fv1 ≈ 5.7 Hz and the natural frequency of the first torsional mode is fϕ1 ≈ 138.9 Hz.
Navigating Expensive and Complex Design Spaces Using Genetic Algorithms
Authors: Zimmerman David C. 
Published: February 2021

Abstract
The overall objective of this study is to formulate and study a generic procedure for navigating expensive and complex design spaces. The term generic is meant to imply that the procedure would be equally valid in exploring design problems in a multitude of fields. The term expensive design space implies that the computational cost, or burden, associated with a single function is considered “large”. What is desired is a methodology which can identify “promising regions” of the design space using as few function evaluations as possible.
To approach this problem, a neural network approach is developed to serve as an inexpensive and generic function approximation procedure. The genetic algorithm was selected as the optimization technique based on its ability to search multi-modal, discontinuous, mixed parameter, and noisy design spaces.
Dynamics of a Vibro-Impacting Hinged Beam: Rigid and Flexible Models
Authors: Fegelman Karen J. L. , Grosh Karl 
Published: February 2021

Abstract
This study investigates the behavior of a vibro-impacting system with a rigid body mode. The model problem has been formulated as both a one-DOF and a multi-DOF piecewise linear system. The behavior of the models for a base excitation frequency range of 50–200 Hz (4.9–19.5% of the fundamental natural frequency of the in-contact case) is shown for constant base motion acceleration and displacement. It is seen that the models do not predict the same motion for the constant acceleration case, but agree quite closely for the constant displacement case. The system is capable of chaotic motion and several examples of Poincaré sections are shown which suggest the presence of a strange attractor. Future work including analytical methods of analysis for both the one- and multi-DOF systems is discussed.
The Analysis of Deflection and Free Vibration of Laminated Composite Plates Embedded With Shape Memory Alloy Fibers by Finite Element Method
Authors: Zhong W. F. , Zou J. , Tang S. B. 
Published: February 2021

Abstract
In this paper a finite element mode of classical symmetrically laminated composite plates embedded with shape memory alloy fibers is developed. The young’s modulus and recovery stress of SMA are calculated by using Brinson’s one-dimensional constitutive relation. The analysis of deflection and free vibration show that the SMA can reduce the deflection and increase the vibration frequencies significantly, and it is a economical and efficient design to place SMA fibers in the outer-most plies for utilizing their tuning function.
Observations on Simulation of Joint Friction
Authors: Segalman Daniel J. 
Published: February 2021

Abstract
Results of Ungar and of Goodman on dissipation rates in bolted joints are discussed. It is shown that an infinite network of discrete sliders and springs such as specified by Iwan in his study of “parallel-series” systems dissipates energy in a manner similar to that shown by Goodman for frictionally joined continua. The nonlinear nature of frictionally joined continua is further examined by computing the force-acceleration behavior of a single degree of freedom system with one slider, demonstrating interesting multiply closed curves.
AutoSEA2: A New Design Evaluation Tool for Noise and Vibration Engineering
Authors: Bremner Paul G. , Burton Thomas E. , Cunningham Andrew 
Published: February 2021

Abstract
This paper describes the development of the AutoSEA2 statistical energy analysis (SEA) code. The development includes a family of quasi-conformal 3D subsystems; an automatic subsystem connection scheme and implementation of full wave transmission theory for more robust and accurate modeling of junctions. The application of these innovations to the modeling of automobile interior noise demonstrates the potential for this evolution of SEA to define a new “design evaluation” process which is an attractive alternative to finite element methods at the design stage.
A Compliant Double Pin Track Link Model for Multibody Tracked Vehicles
Authors: Choi J. H. , Bae D. S. , Ryu H. S. 
Published: February 2021

Abstract
It is the objective of this investigation to develop compliant double pin track link models and investigate the use of these models in the dynamic analysis of high mobility tracked vehicles. There are two major difficulties encountered in developing the compliant track models discussed in this paper. The first is due to the fact that the integration step size must be kept small in order to maintain the numerical stability of the solution. This solution includes high oscillatory signals resulting from the impulsive contact forces and the use of stiff compliant elements to represent the joints between the track links. The characteristics of the compliant, elements used in this investigation to describe the track joints are measured experimentally. The second difficulty encountered in this investigation is due to the large number of the system equations of motion of the three dimensional multibody tracked vehicle model. The dimensionality problem is solved by decoupling the equations of motion of the chassis subsystem and the track subsystems. Recursive methods are used to obtain a minimum set of equations for the chassis subsystem. Several simulation scenarios including an accelerated motion, high speed motion, braking, and turning motion of the high mobility vehicle are tested in order to demonstrate the effectiveness and validity of the methods proposed in this investigation.
Command Preprocessor for Radiotelescopes and Microwave Antennas
Authors: Gawronski Wodek 
Published: February 2021

Abstract
The LQG controllers, designed for the NASA Deep Space Network antennas have small tracking errors and are resistant to wind disturbances. However, during antenna slewing, they induce limit cycling caused by the violation of the antenna rate and acceleration limits. This problem can be avoided by introduction of a command that does not exceed the limits. The command preprocessor presented in this paper generates a command that is equal to the original command if the latter does not exceed the limits, and varies with the maximal (or minimal) allowable rate and acceleration if the limits are met or exceeded. It is comparatively simple since it requires only knowledge of the command at the current and the previous time instants, while other known preprocessors require knowledge of the terminal state and the acquisition time. Thus, the presented preprocessor is more suitable for implementation. In this article analysis of the preprocessor is presented. Also the performances of the preprocessor itself, and of the antenna with the preprocessor is illustrated with typical antenna commands.
Equations of Motion of Spool Valves With Eccentric Clearance
Authors: Duan Shanzhong , Anderson Kurt S. 
Published: February 2021

Abstract
Equations of motion of spool valves have been established under very ideal conditions. In this paper, some important factors are brought into considerations. One of them is the eccentric clearance existing between the valve spool and the sleeve due to fabrication errors. Another is the viscosity of a Newtonian fluid assumed to flow through the valve, which generally results in shear forces acting on the valve spool. Under these conditions, equations of motion of the spool valves are derived. Concepts of Poiseuille flow and Couette flow are used to obtain axial forces acting on the valve spool. The resulting equations of motion of spool valves have the simple form of a second order linear homogeneous ordinary differential equation under the imposed idealizations. The influence of these factors on the motion characteristics of spool valves are in turn discussed.