Device for towing test of model ship in experimental pool
(57) Abstract:The invention relates to experimental hydromechanics and for the design of equipment for carrying out hydrodynamic and ice studies of models of ships in ice model tank. The invention consists in that the device for towing test of model ship equipped with an additional two rods, two dynamometers, as well as siloperedayuschey plate with a cylindrical sleeve, a support platform with backsplash and bar mechanism. The primary and secondary load cells to form a three-point shift measuring system. Dynamometers through the rod and the frame associated with the towing carriage. A cylindrical sleeve is placed coaxially with a cylindrical bore in the flange of the supporting platform. On the shoulder the printed grid scale mechanism, and a cylindrical sleeve - index. Each of dynamometers contains sensors longitudinal, transverse and vertical forces and is made of two elastic elements, connected in series with each other. The first elastic element is platysternidae elastic element with a Central rod, mostly square in cross section and rectangular is terzani and spokes are made with strain gauges. Spokes made in one piece with the rim and the hub. The movable flange of the first elastic element is rigidly connected with the hub and the rim is connected to the supporting platform. The outputs of the sensors of each dynamometer is connected to the input of the electronic computer. The technical result of the invention consists in extending the range of the simulated processes. 5 Il. The invention relates to experimental hydrodynamics of ship and marine engineering structures and relates to equipment for carrying out hydrodynamic tests of the models in the model tank.A device for towing tests of ship models in the model tank , containing rigidly mounted on the towing carriage frame, a horizontal guide which moves the carriage associated with the dynamometer and provided with rollers, which is a vertical rod connected to the tow in the channel pool model, we have made a prototype.A disadvantage of the known device is the limited range of the simulated processes and reproduced by the dynamometer frequency external hydrodynamic forces, limited component power load. Known wiki drilling platforms) in the dynamic mode of destruction of the ice cover and the consolidated pack jumpers. Special difficulties arise when testing large models prohealthcare offshore structures in ice conditions, due to the significant forces and moments acting on the model, and the lack of rigidity of the experimental setup, performed as a single pole design, and trailed models associated with the dynamometer in a limited area of the fastening rod. In the process of breaking the ice fields have significant amplitude low-frequency oscillations of the model relative to a support mount tow bars. Consequently distorted physical processes of breaking the ice and disrupted the reliability of the measurement information.The claimed invention solves the problem of extending the range of the simulated processes, frequency of external forces played a dynamometer, increase the rigidity of the device and the measurement accuracy in the dynamic mode of destruction of the ice field, especially when testing large models prohealthcare marine engineering structures (including ice-resistant drilling platforms).For this purpose, the device is further provided with two rods, two dynamometers, siloperedayuschey plate with a cylindrical bore in the plate, rigidly fixed on the model, and a support platform connected with dynamometers, which form a tricycle cosmetically system and through the rod performed with variable height transverse rigidity, and a frame associated with a towing carriage, one of dynamometers mounted so that its longitudinal axis coincides with the longitudinal axis of a three-point shift measuring system and with the direction of the towing model, and the other two of the dynamometer are located on the transverse axis of the system is symmetrical about its longitudinal axis, a cylindrical sleeve siloperedayuschey plate is placed coaxially with a cylindrical bore in the flange of the supporting platform can be rotated sloperama plate with the model relative to the vertical axis and fixing the model in a given angular position on the flange of the supporting platform the printed grid scale mechanism, and a cylindrical sleeve siloperedayuschey plates caused the index, each of dynamometers contains sensors longitudinal, transverse and vertical forces and made in the form of series-connected between two elastic elements, one of which is platysternidae elastic element with a Central rod, osnashenye at the same time a whole with them, and the second elastic element is a rim with spokes and the hub, and the spokes are equipped with strain gauges and is an integral whole with the rim and the hub, and 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, the Central core of the first elastic element has in cross section the form mainly of a square, and peripheral rods form mainly rectangles, the axis of the rod coincides with the direction of the longitudinal and transverse axes of the channel of the water tank, while peripheral rods symmetrically located relative to the Central rod, pairs oriented smallest transverse rigidity in the axial direction of the channel of the water tank, on which they are located, the output of sensors each dynamometer is connected to the input of the electronic computer.Mount towed models directly on dynamometers, hanging in turn on the hard bars, the transverse rigidity which increases in the direction to place its seal on the frame of the towing truck, ensures the best possible in the adopted dimensions design gasdynamical mode of destruction of the ice cover.Tricycle device with three dynamometers 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. 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. An important fact is that acting on the towed model from different angles towing significant bending and twisting moments converted a three-point system in the corresponding components of the forces at the points of attachment of the model.Thanks dynamometers released from the action of bending and twisting moments, which increases the measurement accuracy of their forces. Three-shift measuring system in comparison with pillar greatly increases the stiffness of the system model - dynamometer - bar - tow truck. In view of the fact that bending and twisting mwout move the model from these points. Thanks eliminates low-frequency vibrations of the model, characteristic of the pillar system and due to insufficient rigidity of the system in the link model - dynamometer, increases the reliability of the modeling process of breaking the ice fields and measurements.The proposed device is universal and testing of a compact and well streamlined models ( vessel, cylinder, truncated cone) can be performed on one leg with one dynamometer, test models, which have a longitudinal dimension substantially greater than the cross, can be performed on two supports with two dynamometers (both bearings are mounted along the axis of the towing model).In Fig.1 shows a diagram of the device, the side view of Fig.2 is a cross - section of the device along the line a-a of Fig.3, 4 - the design of the dynamometer of Fig.5 is a connection diagram of measuring sensors with mainframe.The device (Fig.1) contains rigidly mounted on the towing carriage 1 frame 2 with the rods 3, which are connected through the dynamometer 4, 5, 6 and the support platform 7 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 is d, which is provided by the ribs 13, made in the form of a rectangular trapezium.Dynamometers made in the form of elastic elements in series 14 and 15 (see Fig. 3,4). Elastic elements 14 are platysternidae springs, containing a Central core 16, the four peripheral rod 17 and a strain transducers 18, concluded between the two flanges 19 and 20 and is an integral whole with them. Elastic elements 15 are rim 21 with spokes 22 and the hub 23. Spokes 22 are equipped with strain gauges 24 and is an integral whole with the rim 21 and the hub 23. Movable flanges 20 patiserrie elastic elements 14 are rigidly connected to the hub 23 of the elastic elements 15 by means of bolts 25 and the rim 21 is also rigidly connected with the supporting platform 7 by bolts 26 (see Fig. 2).Siloperedayuschey plate 8 fixedly connected to the towed model 9, provided with a cylindrical sleeve 27, which caused the index 28, and two rows of holes 29 and 30, which are located on circles having a common center with a cylindrical sleeve 27. The supporting platform 7 is provided with a flange 31 with a cylindrical bore. On the flange of the supporting platform the printed grid scale mechanism 32. Qili the nuclear biological chemical (NBC platform 7, providing the ability to rotate siloperedayuschey plate with the model on the vertical axis. The supporting platform 7 is also equipped with two rows of holes 33 and 34, which are located on circles having a common center with the shoulder 31. Moreover, the diameters of the circles on which there are holes in siloperedayuschey plate and the support platform, and the step between the holes is the same.Holes 29, 33 and 34 made of the same step (7,5o), which is equal to the minimum angle of rotation of the model tests. Holes 30 are made in increments of 2. Thus on the support platform 7 near the attachment of each support are six holes (33, 34) on 4 of them near each foot (total of 12 points) siloperedayuschey plate 8 is rigidly connected with the supporting platform 7 by means of bolts (Fig. not shown) in a fixed angular position of the model, the reference is scaled mechanism.Dynamometers (see Fig. 2) are oriented so that the axis of the rods X', Y' platysternidae elastic element coincide with the directions of the longitudinal X and transverse Y axis channel of the water tank. While peripheral rods 17A (see Fig. 3, 4) located on the axis X', placed symmetrically with the axis X'. Peripheral rods 17B located on the Y-axis', also placed symmetrically relative to the Central rod 16 and is oriented smallest transverse rigidity in the direction of the axis Y'. The Central rod 16 has a cross-sectional shape mainly square (if one of the measured forces Pxor Pysignificantly higher than the other, the cross-section of the Central rod may be in the form of a rectangle), and peripheral rods 17 have a shape in cross section mainly rectangles (such cross-sectional shape of the peripheral rods provides the greatest moment of resistance relative to the moment, twisting the tested model that is necessary to ensure the integrity of the dynamometer in the case of testing the model on single pole or double-seat scheme towing).Dynamometers form a three-point shift measuring system (see Fig. 2) and mounted so that the longitudinal axis X' 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 installed symmetrodonta 18a, attached to the lateral surfaces of the Central rod 16 perpendicular to the axis X', connected in a bridge circuit, which forms the sensor longitudinal force and the strain gages 18b fixed to the side surfaces of the Central rod 16 perpendicular to the axis Y', connected in a bridge circuit, which forms a lateral force sensor . The strain gauges 24, secured to the spokes 22 of the elastic element 15, also connected in a bridge circuit to form the sensor vertical force . Thus, the load at each support contains three load sensor
The electrical outputs of the sensors 35, 36, 37 dynamometer 4, sensors 38, 39, 40 dynamometer 5 and the sensors 41, 42, 43 dynamometer 6 is connected to the input of the electronic computer 44 (see Fig. 5).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 16, 17 and spokes 22. Strain rods and spokes transformations the systematic signals from sensors 35 - 43 dynamometers come to the computer 44, which calculates acting on the towed model forces and moments according to the following algorithms:
< / BR>where PxPyPz, Mx, My, Mz- forces and moments acting on the model with respect to the axes X, Y, Z:
< / BR>- measured components of the force in the direction of the axes X', Y', Z' dynamometers 4, 5, 6, and forces measured by the load cells 4 assigned index 1, and the forces measured by the dynamometer 5 assigned index 2, respectively, the forces measured by the load cell 6, is assigned to the index 3;
Xi, Yi, Zi- coordinates measuring axis sensor i - dynamometer relative to the coordinate system X,Y,Z of the water tank.Due to the fact that one of the dynamometers 3 reference load system is installed so that its longitudinal axis coincides with the longitudinal axis of the system, and the other two of the dynamometer are located on the transverse axis symmetrically relative to the longitudinal axis of the system is significantly simplified system of coefficients in the equations of moments, and with it - yourself equations of moments. The matrix of coefficients, Xi, Yi, Zitakes the form:
< / BR>Xi, Yi, Ziit is shown in Fig. 2, and the i, Yi, Zion the corresponding values of X1X2, Y2,Z1for the proposed design of the device, and taking into account equations forces, takes the form:
< / BR>The main advantage of simplifying the system of equations of the moments is to improve the accuracy of determination of moments, which is achieved by reducing the terms in the equations.Model tests 9 in the ice experienced pool and measurement of forces and moments acting on the model, implemented on several modes of motion of the towing truck 1 on speed. Usually the length of the work area enough for testing at 3 - 4 speeds. After that tow truck 1 with the model 9 is returned to its original position; begins the process of numerazione new ice fields and prepare the device for another series of tests, for example, with the angle of drift of the model . For this, remove the bolts securing the support platform 7 to siloperedayuschey plate 8. Deploy the model 9 for 3 anchor installation at a given angle , which counts for scoring mechanism 28, 32, and fix siloperedayuschey plate with a support platform by bolts through holes 33, 34. The device is ready for a new series of tests.
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.