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Showing papers on "Rotary inertia published in 1995"


Book ChapterDOI
Richard P. Rumelt1
01 Jan 1995
TL;DR: In this paper, the authors argue that strategy scholars have incorrectly borrowed from economists the assumption of organizational plasticity and argue that inertia, rather than plasticity, is the norm in large firms.
Abstract: In this article I argue that strategy scholars have incorrectly borrowed from economists the assumption of organizational plasticity. Particularly in large firms, inertia, rather than plasticity, is the norm. Unfortunately, there can be no simple theory of inertia as its causes are multiple and varied. After sketching out the shapes of the most important sources of inertia, I turn to the problem of overcoming inertia—the question of organizational transformation. Starting with a simple model of organizational capabilities as existing on two levels (unit-based and rooted in coordination among units), I draw some preliminary conclusions about the shape of organizational transformation. In particular, I focus on the interplay between incentive intensity and coordinative capacity and argue that most transformations move through a sequence of phases in which coordinative capacity is first dramatically reduced and then rebuilt along new lines.

322 citations


Journal ArticleDOI
TL;DR: In this article, the exact vibration frequencies of generally laminated beams are found using a new method, including the effect of rotary inertia and shear deformations. But this method is not suitable for rigid structures.

96 citations


Journal ArticleDOI
TL;DR: In this article, a one-dimensional model considering the transverse shear effect and rotary inertia for the free vibration analysis of a sandwich plate with an across-the-width delamination located at the interface between the upper face and core is developed.
Abstract: Consider a sandwich plate with anisotropic composite laminated faces and an ideally orthotropic honeycomb core. In this paper, a one-dimensional model considering the transverse shear effect and rotary inertia for the free vibration analysis of a sandwich plate with an across-the-width delamination located at the interface between the upper face and core is developed. With this model, the natural frequencies and mode shapes of the delaminated composite sandwich beams can be obtained by solving the eigenvalues and eigenvectors of 12 simultaneous homogeneous algebraic equations. Because there are no such general solutions presented in the literature, verification is done by some special cases such as delaminated composite beams (without core) and perfect composite sandwich beams (without delamination). Based upon this general solution, the effects of faces, core, and delamination on free vibration behavior of composite sandwiches are studied thoroughly.

71 citations


Journal ArticleDOI
TL;DR: In this paper, the boundary stabilization of a nonlinear plate model is studied and the equations used take in consideration the in-plane accelerations and the rotary inertia of the cross sections.
Abstract: The boundary stabilization of a nonlinear plate model is studied. The equations used take in consideration the in-plane accelerations and the rotary inertia of the cross sections. Applying linear feedbacks, the authors obtain the exponential decay of the energy.

60 citations


Journal ArticleDOI
TL;DR: In this paper, a Mindlin-Engesser model is developed for the vibration analysis of moderately thick plates with arbitrarily oriented stiffeners, and the resulting energy functionals are minimized using the Ritz procedure with a set of admissible two-dimensional functions expressed in the form of simple polynomials.

53 citations


Journal ArticleDOI
TL;DR: In this article, the authors derived the equation of motion which governs the lateral vibration of a spinning pretwisted beam and applied the Galerkin method to obtain the associated finite element equations of motion.

52 citations


Journal ArticleDOI
TL;DR: In this paper, a transverse vibration model for drill bits is presented which includes the effects of gyroscopic moments and rotary inertia on the natural frequencies of drill bit transverse vibrations.

48 citations


Journal ArticleDOI
TL;DR: In this paper, two sets of exact natural frequency and mode shape formulae for an axially loaded Timoshenko uniform single-span beam carrying elastically supported end masses are derived.

41 citations


Journal ArticleDOI
TL;DR: In this paper, the parametric instability behavior of a plate subjected to localized in-plane compressive or tensile periodic edge loading is studied, considering the effects of transverse shear deformation and rotary inertia.

39 citations


Journal ArticleDOI
TL;DR: In this paper, the exact vibration frequencies for variable cross-section beams are found using the dynamic stiffness matrix approach, and compared with known results of beams with various taper ratios.
Abstract: The Timoshenko beam model incorporates the effect of shear deformations and rotary inertia in the vibration response of beams. For constant cross-section beams it was shown that the effect is dependent on the aspect ratio of the beams, and for beams with large ratio the effect is small. In this work exact vibration frequencies for variable cross-section beams are found using the dynamic stiffness matrix approach. An example is given and compared with known results of beams with various taper ratios.

39 citations


Journal ArticleDOI
TL;DR: In this paper, the effects of geometric non-linearity shear deformation and rotary inertia on a rotating blade subjected to axial periodic forces are studied by Lagrange's equation and a Galerkin finite element method.

Journal ArticleDOI
TL;DR: In this article, the influence of distributed rotary inertia and shear deformation on the motion of a mass-loaded clamped-free Timoshenko beam by means of an exact solution was determined.

Journal ArticleDOI
TL;DR: It is proved that the momentum wheels increase the effective moment of inertia of the gyrostat-satellite system about some desired axis and a new set of stability criteria is obtained which includes the effects of the coupling between the orbital and attitude dynamics and may be useful in the design of attitude control systems for large spacecraft in low Earth orbit.
Abstract: The steady motions of a rigid body rotating about its maximum principal axis of inertia, while the radius vector lies in the direction of its minimum principal axis of inertia, is known to be stable in the sense of Lyapunov. Due in part to their stowed configuration in launch vehicles, however, satellites typically have an initial rotation about their minimum principal axis of inertia. Such rotation may be unstable in the presence of some dissipations. This paper investigates the effect of momentum wheels on the stability of steady motions. It is proved that the momentum wheels increase the effective moment of inertia of the gyrostat-satellite system about some desired axis. Stability of the steady rotation about the desired axis can be established only for the case when the moment of inertia of the axis aligned with the radius vector is smaller than that of the axis of linear momentum. A new set of stability criteria is obtained which includes the effects of the coupling between the orbital and attitude dynamics and may be useful in the design of attitude control systems for large spacecraft in low Earth orbit. >

Journal ArticleDOI
TL;DR: In this article, an improved transfer matrix technique is applied to study the dynamics of a bottomhole assembly (BHA) system which is always subject to a large axial load.

Journal ArticleDOI
TL;DR: In this article, a finite element model based on a higher order shear deformation theory was used to investigate the harmonic response of composite beams. But only uniaxial bending is considered and the interlaminar shear stresses are neglected.

Journal ArticleDOI
TL;DR: In this article, the authors considered the parametric instability of a cantilever pretwisted beam rotating around its longitudinal axis at a time-dependent speed which contains a steady state part and a small periodically fluctuating component.

Journal ArticleDOI
TL;DR: In this article, the exact vibration frequencies of multi-span laminated beams are found using the exact element method, including the effect of rotary inertia and shear deformations.

Journal ArticleDOI
TL;DR: In this paper, the free vibration analysis of skew Mindlin plates with intermediate parallel stiffeners attached in two directions is presented, where the Mindlin theory is used to account for the effects of transverse shear deformations and rotary inertia of the plate while the Engesser theory associated with the consideration of torsion is employed for stiffeners.
Abstract: This paper presents a formulation for the free vibration analysis of skew Mindlin plates with intermediate parallel stiffeners attached in two directions The Mindlin theory is used to account for the effects of transverse shear deformations and rotary inertia of the plate while the Engesser theory associated with the consideration of torsion is employed for stiffeners Based on these two theories, the energy functionals for the plate system have been derived To obtain the vibration frequencies, these energy functionals are minimized with the shape functions assumed in a set of two-dimensional mathematically complete polynomials This procedure has been implemented numerically to compute the vibration solutions Convergence studies have been performed to verify the accuracy of this method Sets of first known results have been presented for several stiffened plate structures

Journal ArticleDOI
TL;DR: In this article, a higher-order shear deformation theory, which includes transverse shear strain and rotary inertia, is developed to model the vibration characteristics of the shell.
Abstract: This article presents the vibration analysis of thick doubly curved shallow shells having curvilinear planform. The Gaussian curvature of shell varies from positive (such as spherical) to negative (such as hyperbolic paraboloidal). The boundaries are constrained with either soft-simply supported or fully clamped edges. A higher-order shear deformation theory, which includes transverse shear strain and rotary inertia, is developed to model the vibration characteristics of the shell. The inclusion of Lame parameters in the present formulation accounts for the presence of shell curvature and yields cubic transverse shear strain distribution in contrast with the existing quadratic expressions. A set of versatile, globally continuous shape functions is adopted in the Ritz numerical procedure to approximate the displacement and rotation fields. A set of new results for a wide range of shell configurations is presented with some selected contour and three-dimensional displacement mode shapes.

Journal ArticleDOI
01 Jan 1995
TL;DR: It has been known for some time that the torsional vibration of reciprocating engines and pumps cannot be modelled accurately by representing the reciprocating mechanism by a constant inertia as discussed by the authors.
Abstract: It has been known for some time that the torsional vibration of reciprocating engines and pumps cannot be modelled accurately by representing the reciprocating mechanism by a constant inertia. Ther...

Journal ArticleDOI
TL;DR: In this article, the free vibrational properties of composite noncircular cylindrical shells are investigated using a combination of Bezier functions and beam functions to describe the displacement fields along the circumference and longitudinal directions of the shell surface.
Abstract: The free vibrational characteristics of composite noncircular cylindrical shells are investigated in this paper. The shells are composed of layered media of different material properties. The thickness of each layer is considered to be constant. First order composite shell theory, which includes the effects of shear deformation and rotary inertia, is used in the formulation. A combination of Bezier functions and beam functions is used to describe the displacement fields along the circumference and longitudinal directions, respectively, of the shell surface. The shell is modelled using a number of curved cylindrical panels. Displacement (C0 ), slope (C1 ) and curvature (C2 ) continuities between the panels are enforced by proper blending of the Bezier curves. Numerical results are included for a circular sandwich shell and a two-layer cross-ply oval cylinder that provide excellent agreement with those from the literature. The natural frequencies of clamped oval sandwich cylinders made of stiff outer layers and light middle layer are also presented.

Patent
03 Apr 1995
TL;DR: In this article, an inertia lowering control apparatus for a two-mass inertia system, having a motor (induction motor), a load of the motor, and a flexible drive shaft having a low rigidity interconnected between the motor and load, is used to suppress an axially torsional vibration occurring on the flexible shaft.
Abstract: An inertia lowering control apparatus for a two-mass inertia system, the two-mass inertia system having a motor (induction motor), a load of the motor, and a flexible drive shaft having a low rigidity interconnected between the motor and load, is used to suppress an axially torsional vibration occurring on the flexible shaft in the two-mass inertia system. For example, the first-order lag filter having a transfer function as 1/(1+STF) is added at an output portion of the Simulator Following Control section which serves as a disturbance suppression circuit together with a shaft torque estimating observer to estimate a shaft applied torque τS. A simulation of the above-described example indicated that even if the observer gain of the shaft torque estimating observer was relatively small, the effect of suppressing the axially torsional vibration was remarkable.

Journal ArticleDOI
TL;DR: In this article, the stability of a rotating cracked shaft subjected to the end load, an axial compressive force, is studied and the influences of the existing open crack on the natural whirling speeds of the shaft are discussed.

Journal ArticleDOI
TL;DR: In this article, a thermal postbuckling analysis for a moderately thick rectangular plate subjected to uniform and non-uniform tent-like temperature loading and combined axial compression and uniform temperature loading is presented.
Abstract: A thermal postbuckling analysis is presented for a moderately thick rectangular plate subjected to (1) uniform and non-uniform tent-like temperature loading; and (2) combined axial compression and uniform temperature loading. The initial geometrical imperfection of plate is taken into account. The formulations are based on the Reissner-Mindlin plate theory considering the effects of rotary inertia and transverse shear deformation. The analysis uses a deflection-type perturbation technique to determine the thermal buckling loads and postbuckling equilibrium paths. Numerical examples are presented that relate to the performances of perfect and imperfect, moderately thick rectangular plates and are compared with the results predicted by the thin plate theory.

Patent
28 Sep 1995
TL;DR: In this paper, speed n and indicated torque MM are measured under controlled operating conditions in both a run-up phase as well as in a coasting phase, in order to eliminate the loss moment in the determination of the moment of inertia.
Abstract: For largely automatic determination of the moment of inertia of, in particular, an internal combustion engine on a testing stand, speed n and indicated torque MM are measured under controlled operating conditions in both a run-up phase as well as in a coasting phase. In order to eliminate the loss moment in the determination of the moment of inertia, the measuring points of the respectively same speed from the run-up phase and the coasting phase are interpreted in combination, this enabling an exact determination of the moment of inertia in a very simple way with the devices that are usually already present at a testing stand.

Journal ArticleDOI
TL;DR: In this paper, the instantaneous squeeze-film force between a heat exchanger tube and a support plate is studied, based on a two-dimensional rectangular plate model, and a short-sleeve squeezefilm model for arbitrary tube motion is developed.

Patent
25 Oct 1995
TL;DR: In this paper, a method and system of damping nutation of a spacecraft (20) having a desired spin axis along a first principal inertia axis utilizes a momentum source (28) oriented along a second primary inertia axis perpendicular to the first principal inertial axis.
Abstract: A method and system of damping nutation of a spacecraft (20) having a desired spin axis along a first principal inertia axis utilizes a momentum source (28) oriented along a second principal inertia axis perpendicular to the first principal inertia axis. An angular rate of the spacecraft (20) is sensed along an axis transverse to both the first principal inertia axis and the second principal inertia axis. An angular rate signal representative of the angular rate is generated. The angular rate signal is processed to form a control signal representative of a desired torque to drive the momentum source. The desired torque has a first additive component proportional to a derivative of the angular rate to critically damp the nutation under an at least second order model of the spacecraft (20). The momentum source (28) is driven in dependence upon the control signal. Preferably, the desired torque has a second additive component proportional to a momentum stored in the momentum source (28) to inhibit a conversion of the nutation into a tilt of the desired spin axis.

Journal ArticleDOI
TL;DR: A general finite element formulation using cubic Hermitian interpolation for dynamic analysis of pipes conveying fluid is presented in this paper, where both the effects of shearing deformations and rotary inertia are considered.
Abstract: A general finite element formulation using cubic Hermitian interpolation for dynamic analysis of pipes conveying fluid is presented. Both the effects of shearing deformations and rotary inertia are considered. The development retains the use of the classical four degrees-of-freedom for a two-node element. The effect of moving fluid is treated as external distributed forces on the support pipe and the fluid finite element matrices are derived from the virtual work done due to the fluid inertia forces. Finite element matrices for both the support pipe and moving fluid are derived and given explicitly. A numerical example is given to demonstrate the validity of the model.

Journal ArticleDOI
TL;DR: In this article, the problem of the nonstationary vibrations of an infinite elastic uniform thick plate resting on a thermoelastic isotropic half-space is solved, and the equations of the plate motion take into consideration the rotary inertia and transverse shear deformations.
Abstract: The problem of the nonstationary vibrations of an infinite elastic uniform thick plate resting on a thermoelastic isotropic half-space is solved. The equations of the plate motion take into consideration the rotary inertia and transverse shear deformations, and the half-space equations take the thermal flow lag into account. Both welded and smooth contacts between layer and half-space are considered. Nonstationary vibrations are excited by the instantaneous change in the ambient temperature above the plate to some magnitude that then does not change with time or by the instantaneous change in the plate temperature. The plate nonstationary vibrations, in their turn, give rise to three types of plane surface of strong discontinuity propagating in the thermoelastic half-space. The solution behind the wave fronts up to the contact boundary is constructed by virtue of ray series. Unknown functions entering into the ray series coefficients and into the equations of the plate motion are determined from the bound...

Journal ArticleDOI
TL;DR: In this paper, the authors explored a new technique to improve dynamic response and vibration characteristics of sandwich beams with composite skins and viscoelastic core by using 55-Nitinol shape memory alloy (SMA) wires.
Abstract: The objective of this paper is to explore a new technique to improve dynamic response and vibration characteristics of sandwich beams with composite skins and viscoelastic core by using 55-Nitinol shape memory alloy (SMA) wires. The SMA wires are embedded at the interfaces between the composite skins and the viscoelastic core. The Timoshenko beam theory including the effects of transverse shear deformation and rotary inertia was used. A coupled dynamic equations of motion with prestress introduced due to activation (or deactivation) of SMA wires were developed. Numerical results include nonlinear natural frequency of free vibration of mode I as a function of the amplitude of vibration and the dynamic response in time domain as well as in frequency domain were presented. The transform from time domain to frequency domain was achieved by using Fast Fourier Transform (FFT). It is observed that the nonlinear natural frequency strongly depends on the amplitude of vibration. As the amplitude ratio becomes small (less than 0.1) the nonlinear frequency agrees well with the linear frequency. Very significant differences in dynamic responses were observed for cases when SMA wires were activated and SMA wires were not activated.