Showing papers on "Critical speed published in 1970"
TL;DR: In this article, the non-linear response of an elastic string to a moving load is studied, using a special perturbation method, and solutions are obtained that are valid throughout a particular neighborhood of the critical speed of the linear theory.
Abstract: The non-linear response of an elastic string to a moving load is studied, using a special perturbation method. Solutions are obtained that are valid throughout a particular neighborhood of the critical speed of the linear theory. The solutions show how the transitions from subcritical responses to supercritical responses, and vice versa , take place near the critical speed.
18 citations
TL;DR: In this article, an analysis which predicts that multirecessor hydrostatic journal bearings exhibit dynamic instability at and above a certain speed of shaft rotation is summarized. But this instability is characterized by the centre of the shaft exercising vibrations in a closed orbit of high eccentricity at a frequency equal to one half of the critical shaft speed.
Abstract: An analysis which predicts that multirecess hydrostatic journal bearings exhibit dynamic instability at and above a certain speed of shaft rotation is summarized. This instability is characterized by the centre of the shaft exercising vibrations in a closed orbit of high eccentricity at a frequency equal to one half of the critical shaft speed. Futhermore, this frequency corresponds to the natural frequency of the system at zero eccentricity in the absence of shaft rotation. An expression for the critical speed of an orifice compensated bearing with four recesses is given and an experimental verification of these predictions is presented.
9 citations
TL;DR: In this paper, the nonlinear response of an elastic beam to a moving transverse load is studied, using a special perturbation method, and solutions are obtained that remain valid throughout some neighborhood of the critical speed of the linear beam theory.
4 citations
Patent•
28 Oct 1970
TL;DR: In this article, a system involving co-ordinated control of the speed and pitch of an engine-driven ship's propeller is presented, where consecutive periodic measurements of fuel consumption per engine revolution are compared and the speed is automatically adjusted until the fuel consumption is a minimum.
Abstract: 1,210,387 Automatic control of ship propulsion INSTITUT FUR SCHIFFBAU Nov 13, 1967, No51488/67 Heading G3R In a system involving co-ordinated control of the speed and pitch of an engine-driven ship's propeller, consecutive periodic measurements of fuel consumption per engine revolution are compared and the speed and pitch automatically adjusted until the fuel consumption per revolution is a minimum As shown, a signal dependent on the speed of a ships' propeller 11 driven by an engine 6 is produced by a transducer 9 and compared with a desired speed signal selected by manual adjustment of a lever 1 so that any difference is effective to correct the speed by operation of an engine speed governor 5 Signals which are a function of propeller thrust and pitch are produced by transducers 12 and 13 and compared with a desired value selected by adjustment of a lever 19 controlled automatically by a member 18 in correspondence with lever 1, or manually, so that any difference is effective to vary propeller pitch by operating a controller 14 through means 15 which limit the variation if fuel consumption is excessive The quantity of fuel used per engine revolution is computed at 7 from a fuel-flow transducer 8 and speed transducer 9 and periodically stored and compared with the previous measurement at 16 Any differences cause adjustment of the speed datum and, by virtue of thrust transducer 12, the pitch datum, until fuel consumption per engine revolution reaches a minimum If a unit 2, responding to transducer 9, detects that a critical speed has existed for more than a predetermined time it causes a shift away from this speed
2 citations
1 citations