Showing papers on "Rotary inertia published in 1979"

Dynamic Buckling of a Nonlinear Timoshenko Beam

Abstract: The transient motion that results when an ended-loaded column buckles is studied using a nonlinear Timoshenko beam theory. The two-time method is used to construct an asymptotic expansion of the solution. The results are then compared with those of a previous analysis of the same problem that employed the Euler-Bernoulli beam theory. Thus, the effects of shear deformations and rotary inertia on the dynamics of the column are explicitly demonstrated.

Nonlinear Inertia Forces on Bodies

Abstract: The theoretical influence of convective acceleration terms on the inertia force on a body is considered. The assumptions involved in using the inertia force are reviewed and an expression is derived for the inertia force acting on a body subjected to an unsteady and nonuniform flow of an inviscid fluid. Applications to a submerged sphere and to horizontal and vertical cylinders in waves are considered and differences between alternative predictions of the nonlinear inertia forces are compared. It is reassuring to find that the predicted forces are generally less than those calculated when convective acceleration terms are neglected.

Moving load on initially stressed thick plates attached together by a flexible core

Abstract: Vibrations of an infinitely long, prestressed double strip-plate system are studied analytically. The plates are attached together by a flexible core and one of the plates is subjected to a line load which moves with a constant speed along the plate. The constant, uniform prestresses are parallel to and perpendicular to the infinite edges of the plates. The solution is presented within the framework of a plate theory which includes the effects of shear deformation and rotary inertia. Critical characteristic parameters of the system are defined. An example is provided where the bending moments of the plates are calculated. From the results of theoretical analysis, it becomes evident that the prestresses in the system have considerable effect upon the dynamic behaviour of the system.

Fast locking automatic seat belt retractor

Abstract: 1. An automatic quick-locking belt retractor comprising a main housing (14), a winding shaft (2) with associated winding spring and belt (1) wound thereon and a locking mechanism comprising an inertia force sensor (8, 9), a movably arranged locking pawl (4), a locking sprocket (3), a control member (5, 6) mounted concentrically with respect to the winding shaft (2) in the housing, with an arresting drive disc (5) with internal tooth arrangement (5d), which is freely rotatable concentrically with respect to the winding shaft (2) and relative thereto, a control sprocket (6) with external tooth arrangement (6c) and a freely rotatably mounted pawl (10), and a rotary inertia weight (7) for actuating the locking pawl (4) in the event of excessive belt acceleration characterised in that the control member (5, 6) carries the inertia force sensor (8, 9), that the arresting drive disc (5) has a control cam (5a) for engagement of the locking pawl (4) into the locking sprocket (3), that the rotary inertia weight (7) is arranged movably relative to the control sprocket (6), that the mounting location (10a) of the pawl (10) is arranged eccentrically, forming a long (10e) and a short lever (10f), and that projections (7b, 7c) on the rotary inertia weight (7) can be brought into engagement with the ends (10d, 10c) of the pawl (10).

Parametric energy converter

Abstract: A method and apparatus for converting thermal energy into mechanical energy by parametric pumping of rotary inertia. In a preferred embodiment, a modified Tesla turbine rotor is positioned within a rotary boiler along its axis of rotation. An external heat source, such as solar radiation, is directed onto the outer casing of the boiler to convert the liquid to steam. As the steam spirals inwardly toward the discs of the rotor, the moment of inertia of the mass of steam is reduced to thereby substantially increase its kinetic energy. The laminar flow of steam between the discs of the rotor transfers the increased kinetic energy to the rotor which can be coupled out through an output shaft to perform mechanical work. A portion of the mechanical output can be fed back to maintain rotation of the boiler.

Second order nonlinear equations of motion for spinning highly flexible line-elements

Abstract: A formulation is given for the second order nonlinear equations of motion for spinning line-elements having little or no intrinsic structural stiffness. Such elements have been employed in recent studies of structural concepts for future large space structures such as the Heliogyro solar sailer. The derivation is based on Hamilton's variational principle and includes the effect of initial geometric imperfections (axial, curvature, and twist) on the line-element dynamics. For comparison with previous work, the nonlinear equations are reduced to a linearized form frequently found in the literature. The comparison has revealed several new spin-stiffening terms that have not been previously identified and/or retained. They combine geometric imperfections, rotary inertia, Coriolis, and gyroscopic terms.

Finite-Element Analysis of Laminated Composite-Material Plates.

Abstract: : A finite-element formulation of the equations governing the laminated anisotropic plate theory of Yang, Norris and Stavsky, is presented. The theory is a generalization of Mindlin's theory for isotropic plates to laminated anisotropic plates and includes shear deformation and rotary inertia effects. Finite-element solutions are presented for rectangular plates of antisymmetric angle-ply laminates having material properties that are typical of a highly anisotropic composite material. Two sets of material properties that are typical of advanced fiber-reinforced composites are used to show the parametric effects of plate aspect ratio, length-to-thickness ratio, number of layers, and lamination angle. The element is also employed to study the bending of laminated, anisotropic bimodulus material-plates. Results are presented for single-layer and two-layer cross-ply rectangular plates subjected to sinusoidal loading. The report also presents a C deg. finite element for the von Karman equations of thin elastic plates.

Uściślony opis drgań wymuszonych linii wałów z uwzględnieniem asymetrii sztywności na zginanie i podatności fundamentów

Abstract: The paper deals with linear vibrations of shaftings at periodic excitations. The derived formulae are describing the influence of an internal damping, constant axial force, shear forces and rotary inertia on flexural Vibrations. There are also given the formulae concerning with longitudinal and torsional vibrations with an internal damping taken into account. The solution method for a flexural vibrations problem in flexible supported, geared shaft systems with flexural rigidity asymmetry is presented. The possibility of applying, the deformable (or stiff) finite element technique is illustrated for the case of a crankshaft. It is assumed that each node (or stiff finite element) has 6 degrees of freedom. The size of system matrices is reduced by means of transfer matrices related to solution coefficients for adjacent shaft pieces or by use of transfer matrices referred to one crank when the finite element technique is applied.

On the Transient Response of Long Beams Subjected to High Velocity Transverse Impact

Abstract: This paper deals with the plastic deformation of long beams subjected to high velocity transverse impact. The effects of rotary inertia, shear force and strain-rate on the transient response are discussed from the theoretical and experimental results for pure aluminum. It is shown that the deflection curves calculated by the strain-rate dependent traveling-wave theory are in much better agreement with the experimental results than those obtained by the elementary theory. In this computation, the linearized constitutive equations by Malvern are used. The values of the strain-rate constants used in the computation were obtained from the high velocity compression and high angular velocity torsional tests on the same material.