Showing papers on "Inertia published in 1986"
TL;DR: In this paper, a Lagrange multiplier technique is employed to impose that, in the contact area, the surface displacements of the contacting bodies are compatible with each other, and Coulomb's law of friction is enforced in a global sense over each surface segment.
284 citations
TL;DR: In the absence of particle inertia, a fraction of the particles may be suspended indefinitely, but inertia, however weak eventually causes all particles to settle out at a rate that over most parametric ranges is faster than in still fluid as mentioned in this paper.
Abstract: Statistics have been computed for the motion Of small particles settling under gravity in an ensemble of randomly oriented, periodic, cellular flow fields that are steady in time. The particles are small, spherical, and subject to a quasi-steady Stokes drag force from the flow. In the absence of particle inertia, a fraction of the particles may be suspended indefinitely, but inertia, however weak eventually causes all particles to settle out at a rate that over most parametric ranges is faster than in still fluid. More surprisingly, particles with small free fall velocity and weak inertia show a strong tendency to collect along isolated paths. Reducing inertia does not greatly alter this process, but only delays it.
199 citations
TL;DR: In this article, a detailed analytical, experimental and numerical study concerning determination of an optimum specimen geometry used in the Split-Hopkinson Pressure Bar (SHPB) test technique is presented, where the longitudinal and axial specimen inertia and the effects of interfacial friction between the Hopkinson bars and cylindrical specimen are considered.
108 citations
TL;DR: In this paper, a new method for free-vibration analysis using the boundary element technique is presented, which utilizes a fictitious vector function to approximate the inertia forces and then uses the well-known concept of complementary functions and particular integrals to solve the resulting governing differential equations.
Abstract: A new method for the free-vibration analysis using the boundary element technique is presented The method utilizes a fictitious vector function to approximate the inertia forces and then uses the well-known concept of complementary functions and particular integrals to solve the resulting governing differential equations The necessary particular integrals are defined for the two and three-dimensional analyses, and the present formulation is applied to a number of two-dimensional problems to show its accuracy and efficiency in the solution of realistic engineering problems
99 citations
07 Apr 1986
TL;DR: Algorithms for the identification of the following robot dynamics parameters are presented: linkcenter of mass positions, link inertia matrices, joint friction coefficients, load mass, load center of mass position and load inertia matrix.
Abstract: Algorithms for the identification of the following robot dynamics parameters are presented: link center of mass positions, link inertia matrices, joint friction coefficients, load mass, load center of mass position and load inertia matrix. Required measurements are the joint forces/torques and the resulting joint motion (joint position, velocity and acceleration). Software implementations are used to show how the algorithms perform on simulated measurement data.
94 citations
TL;DR: In this article, the inertial range structure of turbulence is studied on the basis of an approximation derived by a systematic method of Lagrangian renormalized expansions, which is also applied to the problem of a passive scalar field convected by turbulence.
Abstract: The inertial range structure of turbulence is studied on the basis of an approximation derived by a systematic method of Lagrangian renormalized expansions. This method is also applied to the problem of a passive scalar field convected by turbulence, and some of its consequences are examined. Numerical values are obtained for various dimensionless constants in the inertial range including those in the k−5/3 spectrum law for the turbulent energy and the scalar field.
66 citations
TL;DR: In this article, the effects of fluid inertia and turbulence on the force coefficients of squeeze film dampers are investigated analytically and both the convective and the temporal terms are included in the analysis of inertia effects.
Abstract: The effects of fluid inertia and turbulence on the force coefficients of squeeze film dampers are investigated analytically. Both the convective and the temporal terms are included in the analysis of inertia effects. The analysis of turbulence is based on friction coefficients currently found in the literature for Poiseuille flow. The effect of fluid inertia on the magnitude of the radial direct inertia coefficient (i.e., to produce an apparent added mass at small eccentricity ratios, due to the temporal terms) is found to be completely reversed at large eccentricity ratios. The reversal is due entirely to the inclusion of the convective inertia terms in the analysis. Turbulence is found to produce a large effect on the direct damping coefficient at high eccentricity ratios. For the long or sealed squeeze film damper at high eccentricity ratios, the damping prediction with turbulence included is an order of magnitude higher than the laminar solution.
57 citations
TL;DR: In this paper, the authors present a new approach to design a simple manipulator with better dynamic behavior based on eliminating coefficients of nonlinear terms in the system's kinetic and potential energy equations.
Abstract: This paper presents a new approach to designing a simple manipulator with better dynamic behavior. The method is based on eliminating coefficients of nonlinear terms in the system's kinetic and potential energy equations. Accordingly, a set of design criteria regarding the link's inertia distribu tion can be established for each robot type. A robot designed to satisfy these criteria will result in much simplified dy namics. Also we find that for some configurations of three- and four-link robots, it is possible to design for completely linearized dynamic equations.
53 citations
53 citations
TL;DR: One of the key assumptions involved in the stochastic formulation of quantum mechanics, the inverse proportionality of the quantum diffusion constant to the inertial mass, is shown to be amenable to experimental test as mentioned in this paper.
50 citations
TL;DR: In this article, the effects of the particle inertia and the crossing-trajectories effect on the particle dispersion were investigated, and it was shown that the effect of the crossing trajectories on particle motion is very significant.
Abstract: A set of second-order modelled equations for the motion of particles are presented. We consider the effects of the particle inertia and the crossing-trajectories effect on the particle dispersion. A simple case of a particle mixing layer in a decaying homogeneous turbulence for light and heavy particles is calculated. The results show that the crossing-trajectories effect on particle dispersion is very significant, while inertia only has a slight effect. This behaviour has been observed in experiments (Wells & Stock 1983) and is well predicted by an asymptotic analysis (Csanady, 1963). The calculation also shows that there is a significant difference between Favre-averaged particle velocity and conventional-averaged particle velocity in the low-particle-concentration region. All calculations are in good agreement with Wells & Stock's experimental data.
Patent•
30 Apr 1986
TL;DR: In this paper, a flywheel energy storage system with a continuously variable output speed employing a pair of variable inertia flywheels for energy storage and transfer and a second pair of Variable Inertial Flywheel (VIN) for control of the inertia of the first flywheel was presented.
Abstract: A flywheel energy storage system with a continuously-variable output speed employing a pair of variable inertia flywheels for energy storage and transfer and a second pair of variable inertia flywheels for control of the inertia of the first flywheels. A gear type transmission is provided for coupling each of the flywheels to an input shaft and each of the flywheels with an output shaft with multiple output shaft speed ranges. A system for automatic control of shifting is provided.
TL;DR: In this paper, the effect of flow inertia on vertical, natural convection in saturated, porous media is investigated. But the authors focus on the non-Darcy regime, where the thermal boundary layer is thicker than the pure-darcy flow and the maximum temperature gradient decreases with increasing ξ.
TL;DR: In this paper, a numerical simulation of capillary jets motivated by the study of drop-on-demand ink-jet printing is presented for three Weber numbers with a simplified nozzle entry pressure history that has been converted to a velocity history at the nozzle exit by a momentum integral applied to the nozzle region.
TL;DR: In this article, the Lyapunov and Riccati differential equations with periodically time-varying coefficients are considered under the assumption of detectability of the underlying periodic system and two inertia theorems are provided linking the inertia of the solution to the so-called monodromy matrix.
Abstract: The Lyapunov and Riccati differential equations with periodically time-varying coefficients are considered. Under the assumption of detectability of the underlying periodic system, two inertia theorems are provided linking the inertia of the solution to the one of the so-called monodromy matrix.
TL;DR: Experimental pressure distribution measurements in hybrid journal bearings are presented and the influence of inertia forces in the recess outlets and pressure generation in the pockets for high rotating speeds are shown in this paper, which is in good agreement with the theoretical results given by an established model.
01 Apr 1986
TL;DR: A manipulator design theory for reduced dynamic complexity is presented, where the kinematic structure and mass distribution of a manipulator arm are designed so that the inertia matrix in the equation of motion becomes diagonal and/or invariant for an arbitrary arm configuration.
Abstract: A manipulator design theory for reduced dynamic complexity is presented. The kinematic structure and mass distribution of a manipulator arm are designed so that the inertia matrix in the equation of motion becomes diagonal and/or invariant for an arbitrary arm configuration. For the decoupled and invariant inertia matrix, the system can be treated as linear, single-input, single-output systems with constant parameters. As a result, the control of the manipulator arm is simplified, and, more importantly, control performance can be improved due to the reduced dynamic complexity. First, the problem of designing such an arm with the decoupled and/or configuration-invariant inertia matrix is defined. The inertia matrix is then analyzed in relation to the kinematic structure and mass properties of the arm links. Necessary conditions for the manipulator arm to possess a decoupled and/or configuration-invariant inertia matrix are obtained. Using the necessary conditions, we find the kinematic structure and mass properties for which the inertia matrix reduces to a constant, diagonal form. For 2 and 3 degree-of-freedom arms, possible arm designs for decoupled and/or invariant inertia matrices are then determined.
TL;DR: In this paper, the authors describe the moderate-amplitude, three-dimensional oscillations of an inviscid drop in terms of spherical harmonics, which are coupled by quadratic nonlinearities caused by inertia, capillarity, and drop deformation.
Abstract: The moderate‐amplitude, three‐dimensional oscillations of an inviscid drop are described in terms of spherical harmonics. Specific oscillation modes are resonantly coupled by quadratic nonlinearities caused by inertia, capillarity, and drop deformation. The equations describing the interactions of these modes are derived from the variational principle for the appropriate Lagrangian by expressing the modal amplitudes to be functions of a slow time scale and by preaveraging the Lagrangian over the time scale of the primary oscillations. The equations describing the motion of axisymmetric resonant modes are integrable. Stochastic motions are predicted for nonaxisymmetric deformations starting from most initial conditions, even those arbitrarily close to the axisymmetric shapes. The stochasticity is characterized by a redistribution of the energy contained in the initial deformation over all the degrees of freedom of the interacting modes.
Patent•
12 May 1986TL;DR: In this paper, the large rotational inertia applied to a driveline component during normal driving conditions is simulated in a test stand that contains a component that driveably connects an input motor and an output motor.
Abstract: The large rotational inertia applied to a driveline component during normal driving conditions is simulated in a test stand that contains a component that driveably connects an input motor and an output motor. A computer repetitively executes an algorithm that produces a commanded torque signal which is supplied as a control signal to the motor drive of one of the electrical motors to produce an output within that motor equal to the commanded torque. The control system applies to the powertrain component under test an inertia that simulates the actual vehicle inertia. The target state of the system, when the vehicle inertia is applied, is completely defined from information known when the component being tested has substantially less inertia applied.
TL;DR: In this paper, extended Nusselt solutions for laminar film condensation on a vertical surface are presented in closed form, and hence applicable for arbitrary parametric values.
TL;DR: In this article, the authors present a two-dimensional and three-dimensional formulation of the system equations of motion of inertia-variant flexible bodies, in particular, Euler parameters are employed to describe the rotations of the body reference in the spatial analysis.
Abstract: The formulation for the dynamic analysis of undamped linear structural systems using the finite element method results in two element matrices; the mass and stiffness matrices, that describe the element inertia and stiffness properties However, these matrices are not sufficient to describe the dynamics of structures that undergo large rigid-body motion Other element matrices, in addition to the mass and stiffness matrices, are required to account for the inertia coupling between gross motion and elastic deformation These matrices are time-invariant and can be generated and assembled in the same manner as the mass and stiffness matrices are assembled in linear structural dynamics An inherent relation between these matrices and the deformable body mean axes exists This paper is the first of two parts It presents the two-dimensional and three-dimensional formulation of the system equations of motion of inertia-variant flexible bodies In particular, Euler parameters are employed to describe the rotations of the body reference in the spatial analysis In Part II [13], this formulation is applied to the impact analysis of a large-scale constrained flexible aircraft which are modeled as a multi-body system consisting of interconnected rigid and flexible components
TL;DR: In this article, the authors extend the Reynolds equation to include the inertia effects in hydrodynamic lubrication and obtain explicitly the inertia contributions to the dynamics of bearings in some particular cases.
Patent•
10 Apr 1986TL;DR: In this paper, the angular speed of a solar panel carried by the satellite is selectively and temporarily varied about an average value for modifying the inertia cross-product thereof and generating an angular momentum transverse to the angular momentum present in said body with a phase with respect to the nutation motion which tends to decrease the amplitude of the NN motion.
Abstract: For controlling nutation of a three-axis stabilized satellite, the angular speed of a solar panel carried by the satellite is selectively and temporarily varied about an average value for modifying the inertia cross-product thereof and generating an angular momentum transverse to the angular momentum present in said body with a phase with respect to the nutation motion which tends to decrease the amplitude of the nutation motion.
01 Jan 1986
TL;DR: In this paper, the frequency dependence of viscous and inertial fluid forces that act on oscillating, isolated bodies of regular geometry was examined and it was shown that the mechanical admittance of a body submerged in a fluid and supported by springs shows a geometry-dependent resonance.
Abstract: We assume that cochlear fluids are Newtonian and show that for physiological stimuli: fluid compressibility is negligible; convective non-linear inertial forces are small; and both viscous and linear inertial forces are appreciable. We examine the frequency dependence of viscous and inertial fluid forces that act on oscillating, isolated bodies of regular geometry. The mechanical admittance of such a body submerged in a fluid and supported by springs shows a geometry-dependent resonance. This resonance has a quality (Q 3dB ) that is less than 1 for an infinitesimally thin plate vibrating in its plane, but can be arbitrarily large both for a sphere and for a circular cylinder oscillating in a direction perpendicular to its long axis. From considerations of hair cells with free-standing stereocilia in the alligator lizard cochlea we conclude that stereociliary tufts in the cochlea could be resonant mechanical systems.
TL;DR: In this paper, a non-linear force matrix for large amplitude free and forced vibrations of circular plates is derived and the finite element method is used to derive the force matrix. And the relations of amplitude and frequency ratio for different boundary conditions and various load conditions are presented.
Abstract: Geometric non-linearities for large amplitude free and forced vibrations of circular plates are investigated. In-plane displacement and in-plane inertia are included in the formulation. The finite element method is used. An harmonic force matrix for non-linear forced vibration analysis is introduced and derived. Various out-of-plane and in-plane boundary conditions are considered. The relations of amplitude and frequency ratio for different boundary conditions and various load conditions are presented.
TL;DR: In this paper, a modification of the dynamic relaxation method is proposed which facilitates static analysis of non-linear problems using continuous loading in time instead of the ordinary step function of time Inertia and damping forces arising during the loading process are kept at a minimum using an optimum load time history.
Abstract: A modification of the dynamic relaxation method is proposed which facilitates static analysis of non-linear problems Continuous loading in time is adopted instead of the ordinary step function of time Inertia and damping forces arising during the loading process are kept at a minimum using an optimum load time history This results from the stationary condition of an appropriate functional The equation of motion is included as a subsidiary condition Continuous load—deflection curves can be obtained An incremental solution is avoided Application of the method is extremely simple Existing programs based on explicit time integration schemes can be easily adapted for it Sample solutions are presented
TL;DR: In this article, the attitude evolution of a perturbed rotation satellite is analyzed to find an analytic solution corresponding to attitude evolution in space of a satellite submitted to disturbing torques, and a method of resolution leading to a formal solution is given here to the first order.
Abstract: This work aims at finding an analytic solution corresponding to the attitude evolution in space of a satellite submitted to disturbing torques. This paper presents a basic frame applicable to any perturbed rotation satellite, and a method of resolution leading to a formal solution which is given here to the first order. Thus, the main problem is the slow rotation of a body with three unequal axes of inertia, essentially submitted to a dominant solar radiation pressure torque, with the axis pointing far away from a position of equilibrium. The comparison of the results with a numerical integration based upon a HIPPARCOS model is convincing.
TL;DR: In this article, an optimal kinematic design of the mechanism satisfying the given aim and optimal cross-sectional areas of the links were determined such that the shaking force trasmitted to the foundations due to the combined effect of rigid-body inertia forces and KED inertia forces is a minimum.
TL;DR: In this paper, the effect of fluid inertia at low Reynolds number is described, by solution of the steady state Navier-Stokes equation in the form of a perturbation expansion, leading to a system of linear partial differential equations with solutions in a Fourier series.