Device for conducting the towing tests of marine engineering facility model in model testing basin

FIELD: experimental hydromechanics; designing of equipment for conducting hydrodynamic and ice searches of marine engineering facility models in model testing basins.

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

 

The invention relates to experimental hydromechanics and for the design of equipment for carrying out hydrodynamic and ice studies of models of marine engineering structures in the model tank.

A device for towing test of model ship in a towing tank basin (see RF patent №2113373, bull. No. 7, 1998), containing a tow truck with fixed frame with three rods, which through the dynamometers and the support platform is connected with the model of the ship, and dynamometers, forming a three-point shift measuring system made in each support in the form of series-connected between two elastic elements, one of which is platysternidae elastic element with sensors longitudinal and transverse forces, located between the two flanges, and the second elastic element is a rim with spokes and the hub, and the spokes are equipped with strain gauges forming the sensor vertical force, the movable flange of the first elastic element is rigidly connected with the hub of the second elastic element, and its rim is connected with the supporting platform, a stationary flanges patiserrie elastic elements rigidly connected through a rod to the frame of the towing truck, we have made a prototype.

However, for the known device characteristic lack of that is the ability to measure forces and moments due to losses, occur in the bearings mounting dynamometers. Measurement error can reach 10% or more. These errors are due to the fact that in the known device, there are no fixed reference point in dynamometers for the unambiguous transformation acting on the device moments in force.

Another disadvantage of the known devices is the occurrence of errors in the measurement of forces and moments in the presence of longitudinal waviness or drawdown track on separate sections, for example, the appearance of defects in the shoes, the locking rails. In this case, the tow truck when driving on the track can be deformed in both longitudinal and transverse directions. This can lead to significant internal forces in the device, if it supports much posted on the towing carriage.

In addition, the device may deviate from the vertical axis, causing the dynamometers additional force proportional to the force of weight of the device and corresponding angles. All of this ultimately may result in reduced reliability and validity of the measurements.

The claimed invention solves the problem of increasing the accuracy of measurement of forces and moments.

For this purpose, the device of the second elastic element is designed as a membrane of an elastic element, the membrane of which is enclosed is between a rigid rim and a hard Central part of this element, which includes a threaded rod with an elastic hinge, mounted on a vertical axis perpendicular to the membrane, and the membrane rim and rigid Central portion with a threaded rod and an elastic hinge is made for a single entity, the rim of the membrane elastic elements are rigidly connected with one of the flanges platysternidae elastic element, and the connection specified is carried out so that the threaded rod is located along the vertical axis of the support and through the elastic hinge rigidly connected with the support plate, fixed on the model, the membrane is equipped with strain gauges connected in a measuring bridge vertical force, while the second flange of each element platysternidae connected with added support plate attached to the rod.

The device, which represents a three-shift measuring system, with three dynamometers strength: longitudinal PX, cross RYand vertical PZmounted in each support, allows towing tests of large prohealthcare models of marine engineering structures under different angles towing in a wide range of modeling of physical-mechanical and geometrical characteristics of the ice field, while providing the best possible in the received ha is arith design the stiffness of the system and eliminating low-frequency vibrations of the model, typical pillar system of measurement.

Although dynamometers measure directly only the three components of forces (longitudinal, transverse, and vertical), the device generally provides a measurement of the three components of forces and three moments in orthogonal planes, acting on the towed model.

To accurately convert the bending and twisting moments tricycle system in force and their measurement is necessary to provide a fixed reference point in the system mounting dynamometers through the support plate with the test model. These "points" are elastic hinges in the threaded rods, which are equipped with membrane sensors vertical force. Thanks to the elastic hinges is provided unambiguous (lossless) transformation acting on the model moments in force.

The connection device frame towing truck through one rod, in contrast to the known device with three spaced along the frame bars, have greatly reduce errors in the measurement of forces and moments due to the longitudinal waviness or drawdown track in some areas, such as defects in the shoes, the locking rails. In addition, it is possible to reduce the angles of deflection of the device from the vertical axis and the resulting additional the forces, proportional to the force of weight of the device.

The essence of the claimed invention is illustrated by drawings, where figure 1 shows a diagram of the device in side view; figure 2 - cross section of the device along the line A-A; figure 3 an enlarged image of the remote element I.

The device (1) contains rigidly mounted on the towing carriage 1 frame 2 of the post 3, through which the load cells 4, 5, 6 and the support platform 7 is connected with siloperedayuschey plate 8 mounted on model engineering structures 9, trailed in the channel of the water tank 10 filled with water 11. On the surface of the water in the channel of the water tank numerouno ice field 12.

Dynamometers are made (see figure 3) in the form of elastic elements in series 13, 14. Elastic elements 13 are platysternidae springs, containing a Central core 15, the four peripheral rod 16 and a strain transducers 17, concluded between the two flanges 18, 19 and made in one piece with them. Elastic elements 14 are made in the form of an elastic membrane elements, membrane 20 which lies between the rigid rim 21 and the rigid Central part 22, is equipped with a threaded rod 23 with the elastic hinge 24. A threaded rod with an elastic hinge is installed on the vertical axis perpendicular to the membrane. The membrane 20 is equipped with strain gauges 25, caterinadiani in the bridge circuit of the vertical dimension with respect to the membrane forces P Z. The rim 21 of the membrane elastic elements is rigidly connected to the flange 19 platysternidae elastic element (screws figure 3 not shown). The specified connection is realized in such a way that the threaded rod 23 is located along the vertical axis of the support and through the elastic hinge 24 rigidly connected with the support plate 7. The flanges 18 of each of platysternidae element are connected to the inputs of the support plate 26, secured to the rod 3 (screws figure 3 not shown). Connection of load cells 4, 5, 6 with the support plate 7 by screws 27. For the alignment of dynamometers on the base plate 7 of the threaded rods 23 provided with a flange 28, and the plate 7 to the respective grooves. The membrane 20, the rim 21, a rigid Central portion 22 with the screw rod 23, the elastic hinge 24 and the flange 28 is made for a single unit.

Siloperedayuschey plate 8 still connected to the towed model 9 and is provided with a cylindrical sleeve 29 with the scale of the grid, and the base plate 7 provided with a cylindrical bore, providing the ability to rotate siloperedayuschey plate 8 together with the model 9 relative to the vertical axis of the device. The base plate 7 provided with holes 30, and siloperedayuschey stove - corresponding screw holes formed on the same diameter and the same pitch as the holes 30. After RA the gate 9 at a given angle relative to the vertical axis of the base plate 7 is rigidly connected with the plate 8 with the screws (2 screws not shown). The channel 31 in the flange 19 serves to strip conductors from the membrane sensor inside platysternidae elastic element 13.

Dynamometers 4, 5, 6 (see figure 1 and 2) form a three-point shift measuring system and installed so that the longitudinal axis of the dynamometer 4 coincides with the longitudinal axis X three-shift measuring system and with the direction of the towing model (X-axis coincides with the longitudinal axis of the channel of the water tank). The other two dynamometer 5 and 6 are installed symmetrically to the X axis, with the longitudinal axis of the load cells 5 and 6 are directed parallel to the axis X of the system.

The device operates as follows. When driving tow truck 1 in the channel of the water tank 10 model 9 marine engineering structures, tow mode " hard saraiki", there hydrodynamic side water and ice forces and moments from breaking the ice field 12. These forces and moments are transmitted to the load cells 4, 5, 6, deforming the measuring rods 15, 16 and membrane 20. Deformation of the rods and membranes converted by the strain gages 17 and 25 into electrical signals proportional to the current forces and moments. And thanks to the elastic hinge 24, which are equipped with dynamometers, transforming moments in force lossless. Electrical signals from the measuring sensors (t and sensor longitudinal forces P X1PX2, RX3three sensor lateral forces PY1PY2, RY3and three sensor vertical forces PZ1PZ2PZ3come on the computer, which calculates acting on the towed model forces and moments on algorithms

PX=PX1+PX2+PX3

PY=PY1+PY2+PY3

PZ=PZ1+PZ2+PZ3

,

,

where

PXPYPZ, MX, MY, MZ- forces and moments acting on the model with respect to the axes X, Y, Z system associated with the channel of the water tank;

Pxi, RYiPZi- components of longitudinal, transverse and vertical forces measured by the load cells 4, 5, 6;

Xi, Yi, Zi- coordinates measuring axis of the respective sensor 1 dynamometer relative to the coordinate system X, Y, Z.

Model tests 9 in the ice model tank and measuring forces and moments have been conducted in several modes of motion of the towing truck 1 on speed. To conduct a new series of tests, for example, with an angle of drift models, towing truck with the test model is derived from the work area pool. Covered new ice box. Deploy the model 9 classifies the flax 3-anchor installation at a given angle, after disconnecting the plate 7 from siloperedayuschey plate 8 (unscrewing the screws that are installed in the holes 30). The angle of spread model 9 counts the scale on the grid 29 and fix siloperedayuschey plate 8 with the support plate 7 by screws through the holes 30. The device is ready for a new series of tests.

1. Device for towing test of model marine engineering structures in the model tank containing a tow truck with a fixed frame with a barbell, which through the dynamometers and the anchor plate is connected with the model, and dynamometers, forming a three-point shift measuring system made in each support in the form of series-connected between two elastic elements, one of which is platysternidae elastic element with sensors longitudinal and transverse forces, located between the two flanges, wherein the second elastic element dynamometer is made in the form of a membrane of an elastic element, the membrane which lies between the rigid rim and a hard Central part of this element, which includes a threaded rod with an elastic hinge, mounted on a vertical axis perpendicular to the membrane, and the membrane rim and rigid Central portion with a threaded rod and an elastic hinge is made for a single unit, the rim of the membrane pack the natives elements rigidly connected with one of the flanges platysternidae elastic element, the specified connection is realized in such a way that the threaded rod is located along the vertical axis of the support and through the elastic hinge rigidly connected with the support plate, fixed on the model, the membrane is equipped with strain gauges connected in a measuring bridge vertical force, while the second flange of each of platysternidae element connected to the inputs of the support plate, fixed on the rod.



 

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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.

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