How agile testing model ship in a towing tank pool and a device for its implementation

 

(57) Abstract:

The invention relates to shipbuilding, in particular to experimental methods test vessel in the model tank, and is intended for maneuvering trials of the vessel in ice. For this curvilinear trajectory model with a radius of circulation set by imposing on the translational motion model with a cart in the channel of the water tank rotational motion with constant angular velocity about a vertical axis. After the model angle of not more than 10° direction model reversiruyut. The device includes a housing placed on the trolley, a vertical shaft on the bearings associated with the actuator to rotate the model includes a motor gear, a lever rigidly connected with a vertical shaft, a load cell with strain gauges and the angle sensor. The device is further provided with an angular gear, the speed sensor truck, limit switches, ski guide, the guide holder and the computer. The invention is aimed at improving the efficiency of the ice fields and ice basin as a whole, as well as improving the reliability of measurement results acting on xperimentally test methods model ship in a towing tank pool.

The known method agile testing model ship in a towing tank basin, which consists in towing the model under the truck around a vertical axis on a circular path, implemented on a rotary installation, and measurement of hydrodynamic forces and moments acting on the model (see, for example, A. C. Vasiliev. The handling of ships, Leningrad: Sudostroenie, 1989). During such movement, the model simulates the movement of a vessel for circulation.

The disadvantage of this method is the need for large radii of rotation to obtain reliable results and, as a consequence of the considerable size of the water tank. With a minimum size equal to 1.5 - 2 m, the working radius of the rotary installation should be 8 - 10 m To obtain more reliable results, the tendency has been to use models with a length of 4 to 6 m For such models, the radius of the installation increases up to 20 - 30 m, and for its placement requires pools of considerable size: up to 75 m in diameter (see, for example, A. C. Vasiliev. The handling of ships, Leningrad: Sudostroenie, 1989, S. 90).

The absence of ice and as a consequence the impossibility of testing models in the ice and measuring forces and moments acting on the model side of the ice field, I is whether the vessel in the model tank using a planar mechanism, which consists in towing the ship with the truck and the imposition on the movement of harmonic oscillations of the model relative to the truck for one coordinate in the transverse direction or their combination and the measurement of the kinematic parameters of motion and hydrodynamic loads acting on the model (see A. C. Vasiliev. The handling of ships, Leningrad: Sudostroenie, 1989, S. 92 - 93), adopted for the prototype.

A disadvantage of the known method are continuously changing radius of circulation and the instantaneous speed of rotation of the center of gravity of the model. This method is not applicable for testing of the ship in the ice, especially in the solid, as the destruction of the ice field moving model of the vessel is random and non-stationary process (see , for example, C. I. Castellan and other ice Resistance movement of the vessel, Leningrad : Sudostroenie, 1968). Therefore, to obtain reliable results of the model must be set constant in time the speed of its center of gravity with a known radius of circulation.

A device for testing ship models in the model tank, comprising a housing with bearings mounted on the carriage and is connected through a vertical shaft with a drive of rotation m is ω, dynamometer with strain gauges and the angle sensor (see ed. St. USSR N 617317, class B 63 B 9/02) adopted for the prototype.

A disadvantage of the known devices is the inability to conduct agile testing in the ice with an adjustable radius of circulation and circular oscillation of the model relative to the vertical axis within the specified limits, and the dynamometer has insufficient accuracy of measurement, as it is installed on the truck and connected to the model through a series of links, including through a gear pair with backlash, and is subject to significant bending moments due to the large distance from the ship on which the impact force. The measuring error of the dynamometer and the design drawbacks of the device, especially manifested when exposed to the shock model of alternating loads, for example, fracture model of the ice field. Drive motor, reduction gear and an electromagnetic brake is rigidly attached to the housing and through him hanging from a dynamometer. Therefore weight and dimensions, and hence the inertia of the drive system model is significantly limited. When exposed to model external variables forces (for example, when the destruction of the ice field case model) is equal to eredivise the dynamometer and distort the measurement result, and the model moves around the vertical axis cannot be considered uniform.

The invention is aimed at providing opportunities for agile testing model of the ship in the ice in a limited width space ice model basin, the efficiency of the ice fields and ice basin as a whole, as well as improving the reliability of measurement results acting on the external forces and moments.

The technical result is achieved in that a curved trajectory with a radius of circulation set by imposing on the translational motion model with a cart in the channel of the water tank, the surface of which is formed ice field with specified physical and mechanical characteristics rotational motion with constant angular velocity about a vertical axis spaced from the center of gravity at a distance r, and after reaching the model angle of not more than 10othe direction of rotation model reversiruyut, and the distance r, the angular velocity of the rotation model and the velocity of the translational motion model with trolley set ratio

< / BR>
where is the angular velocity of rotation of the model around verticali model;

r is the distance from the center of gravity to the axis of rotation,

but the ice loads acting on the model, obtained by subtracting the values of the hydrodynamic loads are pre-defined in the same modes in the absence of the ice field, measured during the test loads in the ice box.

Superimposed on the translational motion model under the truck with a constant velocity V0the rotational motion of the model around a fixed axis with constant angular velocity in the range of angles of spread models are not more than 10owith reversal of the direction of rotation provides movement along a curved trajectory with a known radius of circulation in the confined space of the ice field of the water tank, simulating real processes of vessel movement in the natural environment.

As ice forces and moments acting on the model of the ship, when the destruction of the ice field are constantly changing in time, as random processes, subject to statistical regularities, obtaining reliable results is only possible by averaging them over a period of time during which the speed and the radius of the circulation center of gravity modati model with sufficient practical accuracy can be considered constant for the given values of V0and . When the rotation angles of more than 10omanifest nonlinear effects and the speed of the center of gravity of the vessel can no longer be considered constant: averaging of measurement results of hydrodynamic and ice loads in this case can lead to significant errors. Is ice loads acting on the model, get on the computer by subtracting the magnitude of the hydrodynamic loads from measured during the test loads in the ice box. Hydrodynamic loads are determined beforehand on the same modes of motion in the absence of the ice field.

Device for agile testing model of the vessel in the model tank, comprising a housing placed on the cart, with it set on bearings vertical shaft connected to drive rotation of the model, including the motor, reduction gear, a lever rigidly connected with a vertical shaft, a load cell with strain gauges and the angle sensor, is further provided with an angular gear, the speed sensor truck, limit switches, ski guide, guide holder, and computers, this guide skis mounted on the model symmetrically with respect to its median plane, and dynamome what about the dynamometer and fixing it in position and through the guide holder is connected with the lower end of the vertical shaft with the possibility of vertical displacements of the model and fixing it to the shaft, the upper end of the vertical shaft through an angular gear and clutch is associated with a set on the truck and connected to the horizontal shaft of the motor and gear box, limit switches installed on the trolley at an angular distance of no more than 10orelative to the longitudinal axis of the pool with the possibility of contacting these provisions with the lever, while the dynamometer is made in the form platysternidae system with Central mounted on the axis of rotation model, and four peripheral rods symmetrically positioned relative to the Central rod in the orthogonal planes, one of which passes through the longitudinal axis of the model and the longitudinal axis of the cross section of the Central rod, and the strain gages installed on the Central and peripheral terminals enclosed in the measuring bridges, form the sensors of the longitudinal and transverse forces and torques about the vertical axis, the outputs of which, as well as the angle sensors and the speed of the truck is connected to the computer.

The proposed device provides uniform rotation model of the ship in the ice field, due to the large inertia of the drive system. The moment of inertia of the drive system, including DM number (i = n/nmodels= 3120), defined as the i2JFesignificantly greater than the moment of inertia of the model (i2JFe= 31202(1/2) (50/9.8) 10-2= 248326 kg m2; Jmodels= (1/2)mR2= (1/2) (300/9/8) 1,52= 34 kg m2). Therefore, regardless of operating on the model of alternating external loads arising from the destruction of the ice field that rotates around the vertical axis is performed with a constant angular velocity. This inertial force generated by the model, is void.

Dynamometer mounted on the ship, almost protected from the harmful effects of bending moments, as the shoulder from the point of application of external forces to the axis of the dynamometer is relatively small.

The essence of the claimed invention is illustrated by drawings, where Fig. 1 shows a device for implementing the method agile testing model ship in a towing tank basin, Fig. 2 design of the dynamometer of Fig. 3 - section a-a dynamometer.

Device for agile testing model ship in a towing tank pool consists (Fig. 1) from the housing 1 by bearings 2 mounted on the carriage 3, a vertical shaft 4 with the gear angular gear 5, a horizontal shaft 6 with the gear is imago current 11, which is a thyristor Converter, controlled from the programming device 12, the contact switches 13, 14 are electrically connected with the programming device 12, the guides of the ski 15, mounted on the model of the vessel 16, dynamometer 17 with the shank 18, the lever 19 that is associated with the angle sensors 20 through the lead 21, the speed sensor 22, computers 23.

Dynamometer 17 (Fig. 2, 3) made in the form of platysternidae system and has a Central core 24 and four peripheral rod 25 and 26 with strain gauges 27, 28, 29, concluded between the flanges 30 and 31.

The model of the vessel 16 is immersed in the channel of the water tank filled with water 32, the surface of which is formed ice box 33 required thickness and strength.

The Central rod 24 of the dynamometer is installed on the axis of rotation model Z, and the X' axis of its cross section coincides with the longitudinal axis X of the model ship, the axis Y' parallel to the transverse axis of the model U.

Peripheral rods 25 and 26 are arranged symmetrically relative to the Central rod in the orthogonal planes, with the X' axis of the cross-section of the two rods 25 also coincides with the X axis of the model.

The strain gages most and form the sensor longitudinal forces. The strain gages 28, mounted on the Central rod on the side surfaces normal to the axis Y', enclosed in a measuring bridge and form a lateral force sensor. The strain gages 29, mounted on the peripheral terminals, enclosed in a measuring bridge and form a torque sensor rotation about the z axis.

When you rotate the model on the dynamometer being rigidly connected with it, measures the forces and moment in the coordinate system of the model.

When the execution of a process procedures related to cleaning destroyed during testing ice and freezing new ice fields, the water level and ice fields in the ice pool may vary slightly. To compensate for this change, the level of the lower end of the vertical shaft 4 is connected with the load cell 17 through the guide holder 18 with the possibility of vertical displacements of the model and fixing it to the shaft in accordance with the water level in the pool and the model is loaded.

The proposed method and device are as follows.

The model of the vessel 16 is fixed through the guide skis 15 on the dynamometer 17 at a given distance r from the center of gravity of the model, fix the shaft 4 of the drive maganoy thickness and strength. Tow model 16 under the carriage 3 in the ice box 33 with a constant speed V0that is measured by the speed sensor 22. Include the motor 10, the pre-setting in the software device 12 is required angular velocity of rotation , in accordance with a given velocity V0and the distance r. The rotation of the motor armature 10 through the gear 9, the clutch 8, the horizontal shaft 6, the angular gearbox with gears 5 and 7 and a vertical shaft 4 is passed to the model 16. On the translational motion model of the ship with a speed of V0with the truck superimposed rotational movement of the model relative to truck around a vertical axis coinciding with the longitudinal axis of the shaft 4 and dynamometer 17. When the model angle relative to the direction of towing, coincides with the direction of the longitudinal axis of the canal basin, 10othe arm 19 rigidly mounted on the shaft 4 causes the limit switch 13 or 14, the software device 12 instructs thyristor inverter for reversing the direction of rotation of the engine 10. The model changes the direction of rotation relative to the truck and working mode of movement is repeated again. Acting on the model 16 external hydro is nanometre 17 in the coordinate system of the model. To obtain reliable measurement results enough to propoxylate model at a distance of not less one - half the length of the model. For the model vessel length 4 m one mode of testing ranges from 5.5 m to 15.5 m moving in the ice box. After one of the test conditions alter the velocity V0and/or angular velocity . Usually in one of the ice field is carried out from 3 to 4 runs in different modes. On measured during the tests the values of the speed of the translational movement of the truck V0, the angular speed of rotation of the model (this speed is found from the results of measurements of the angle of rotation over time), and exposed to the distance r from the center of gravity to the axis of rotation define the radius of the circulation model by the formula (1).

Is ice loads acting on the model, get on the computer by subtracting the magnitude of the hydrodynamic loads from measured during the test loads in the ice box. Hydrodynamic loads are determined beforehand on the same modes of motion in the absence of the ice field.

1. How agile testing model ship in a towing tank basin, mainly in the ice, which in tow ship under tow truck is Oh by imposing on the translational motion model with trolley additional movement relative to the truck, and the measurement of kinematic parameters of its motion and hydrodynamic loads acting on the model, wherein the model of the tow in the channel of the water tank, on the surface of the water which is formed ice field with desired physico-mechanical characteristics and movement patterns relative to the truck set in the form of rotational motion with constant angular velocity about a vertical axis spaced from the center of gravity at a distance r, and after reaching the model angle relative to the direction of trolley movement is not more than 10othe direction of rotation model reversiruyut, the distance r, the angular velocity of rotation and the speed of the translational movement is specified by the ratio

< / BR>
where is the angular velocity of the rotation of the model around a vertical axis;

Vo- the velocity of forward movement of the truck;

R is the radius of the circulation center of gravity;

r is the distance from the center of gravity to the axis of rotation,

but the ice loads acting on the model, obtained by subtracting the values of the hydrodynamic loads are pre-defined in the same modes in the absence of the ice field, measured in the process of COI is sane, comprising a housing placed on the cart, with it set on bearings vertical shaft connected to drive rotation of the model, including the motor, reduction gear, a lever rigidly connected with a vertical shaft, a load cell with strain gauges and the angle sensor, characterized in that it is further provided with an angular gear, the speed sensor truck, limit switches, ski guide, guide holder, and computers, this guide skis mounted on the model symmetrically with respect to its median plane, while the dynamometer is connected to the model through the guide skis and installed them with the possibility of moving the model relative to the dynamometer and fixing it in position and through the guide holder is connected with the lower end of the vertical shaft with the possibility of vertical displacements of the model and fixing it to the shaft, the upper end of the vertical shaft through an angular gear and clutch is associated with a set on the truck and connected to the horizontal shaft of the motor and gear box, limit switches installed on the trolley at an angular distance of no more than 10orelative to the longitudinal axis of the pool with the th system with a Central, mounted on the axis of rotation model, and four peripheral rods symmetrically positioned relative to the Central rod in the orthogonal planes, one of which passes through the longitudinal axis of the model and the longitudinal axis of the cross section of the Central rod, and the strain gages installed on the Central and peripheral terminals enclosed in the measuring bridges, form the sensors of the longitudinal and transverse forces and torques about the vertical axis, the outputs of which, as well as the angle sensors and the speed of the truck is connected to the computer.

 

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SUBSTANCE: proposed device includes towing trolley with frame rigidly secured on it; this frame is provided with bar which is connected with model through dynamometers and bearing plate. Dynamometers form three-support force-measuring system; they are provided in each support in form of two interconnected elastic members; one elastic member is made in form of five-rod member provided with longitudinal and lateral force sensors; it is located between two flanges. Second elastic member of dynamometer is made in form of membrane-type elastic member whose membrane is located between rigid rim and rigid central part of this member provided with threaded rod with elastic hinge mounted over vertical axis perpendicularly relative to membrane. Membrane, rim and rigid central part with threaded rod and elastic hinge are made integral. Rim of membrane elastic members is rigidly connected with one of flanges of five-rod elastic member in such way that threaded rod is located along vertical axis of support and is rigidly connected via elastic hinge with bearing plate secured on model. Membrane is provided with resistance strain gages forming vertical force measuring bridge. Second flange of each five-rod member is connected with additional bearing plate secured on bar.

EFFECT: enhanced accuracy of measuring forces and moments.

3 dwg

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