Method and device for testing model of marine engineering structure

FIELD: experimental hydrodynamics.

SUBSTANCE: method comprises making a model dynamically similar to the marine engineering structure in mass, sizes, location of the center of gravity, and inertia moment and mounting the model in the experimental tank by means of anchor-type links provided with dynamometers. The device comprises experimental tank and model provided with anchor-type links for connecting with the frame. The anchor-type links are provided with dynamometers and devices for control of initial tension. The frame has flat horizontal base, vertical pillars , and blocks. The base is provided with the members for securing the vertical pillars at specified points of the base. The vertical pillars are provided with blocks and members that are mounted for permitting movement along the pillars and their locking at a given position. The model is provided with the pickups of angular and linear movements. The outputs of the dynamometers and pickups of angular and linear displacements of the model are connected with the input of the computer.

EFFECT: expanded functional capabilities.

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The invention relates to experimental hydrodynamics of marine engineering structures and relates to methods of testing their models in the model tank and the equipment used.

For the development of offshore oil and gas fields is the design and construction of various marine structures, including, in particular, the floating production platform for continuous operation in deep water in extreme wave and ice conditions.

The most promising platforms for such conditions is a platform with anchor restraint system. These test objects are unique and virtually unstudied in experimental hydrodynamics due to the presence of sophisticated restraint systems.

Testing platforms in the ice model tank, as a rule, is carried out in the mode of the reverse movement, i.e. the model pull towing carriage on the fixed ice field (see, for example, patent RF №216843S, CL 63 In 9/02, G 01 M 10/00). During such tests get information about the size of global ice loads. However, the test platform with anchor restraint system in such a facing movement with rigid fastening it on the dynamometer is not possible to evaluate all kinematic and force characteristics of the platform and anchor ties hold.

There is a method of model testing marine inzhenerno the structures in the ice model tank, namely, that the model is fixed on the dynamometer in the channel of the water tank, must be an ice field or prepare hummocky the formation of fragments of ice, pull with bulldozer towing truck received ice formation on the test model and measure the current on the model of the global forces and moments (see, for example, patent RF №2112689, CL 63 In 9/02, G 01 M 10/00, B. I. No. 16, 1998), adopted for the prototype.

The disadvantage of this method of testing is rigid fastening of the tested models on the dynamometer, restricting her freedom of movement, it is not possible to evaluate all kinematic and force characteristics of the platform and anchor ties her hold, and global forces and moments generated in such a rigid clamping is substantially underestimated.

A device for testing models of marine engineering structures in ice model tank containing a channel filled with water on the surface of which is formed ice box, removable metal farm fixedly connected to the bottom of the channel, a tow Dolly with electric drive and running wheels in contact with the rails laid along the channel, and is equipped with a bulldozer to move the ice field, the speed sensor tow truck, torque and re is asterousia apparatus (see, for example, patent RF №2112689, CL 63 In 9/02, G 01 M 10/00, B. I. No. 16, 1998), as adopted for the prototype.

A disadvantage of the known device is the impossibility of testing anchored objects and measurement of kinematic and force platform parameters and anchor links.

The invention is aimed at providing the possibility of testing the model tank models of marine engineering structures with anchor restraint system and measurement of kinematic and power characteristics as the model as a whole, and anchor links.

For this preliminary model perform dynamically similar marine engineering construction on weight and size characteristics, the position of the center of gravity and moments of inertia with respect to axes X, Y, Z model before testing the model engineering supply anchor restraint system, pinning model in the channel of the water tank passes through equipped with dynamometers force of the tension anchor link that is chosen dynamically similar field object, for which pre-determine and pick up a special booth stiffness characteristics mentioned anchor links, and in the process slipped on easily on the tested model of ice formation measure angular and linear displacement model and anchor links - tension, and the global forces and moments, acting on the model are determined by calculation on the ratios

where

m is the mass of the model structures with regard to added masses of water;

rGis the radius vector of the center of gravity in the associated coordinate system;

the inertia tensor structures (including attached moments of inertia and static moments);

the vector of linear speed of the pole associated coordinate system;

the vector of angular velocity of the pole associated coordinate system;

- the main vector of external forces;

the main moment of external forces about the pole of the associated coordinate system.

In the device for testing models of marine engineering structures in ice model tank to achieve this goal the model is equipped with anchor links, by which it is fixed on the farm, anchor link is equipped with dynamometers tension force and the adjusting device connection on the specified initial tension and made uniform in length, farm includes a flat horizontal base, vertical posts and blocks, and the basis of the farm is equipped with a device mounting uprights with the possibility to set the key in the set points of the base, and vertical Stoics equipped with modules and devices attaching them with the opportunity to offset their height along the racks and fixing in a predetermined position, and the model is equipped with sensors of its angular and linear displacement in the direction of the axes X, Y, Z, the outputs of the load cells tension anchor links, sensors, angular and linear displacements of the model is connected with the input of the computer.

For a correct determination of kinematic and power characteristics required to ensure dynamic similarity model and its anchor restraint system full-scale object. To this end, in the model experiment of dynamic similarity model was carried out according to weight and size characteristics in accordance with the selected scale of the model, the position of the center of gravity and moments of inertia with respect to axes X, Y, Z model, and anchor links was carried out on a number of characteristics of the anchor chains: mass, stiffness, initial tension, the line slack anchor chain and other natural object anchor ties are long or short communication, heterogeneous in length, consisting of a chain of near anchors, steel rope and chain near Lozovoy point. As a result of displacement of communications facilities are stretched due to elastic deformation, turning into pulled the string, and when reverse bias turn into a normal anchor chain. All of these features the STI field anchor ties retention structures are simulated in the model experiment. For this purpose, we first calculate the stiffness characteristics of the selected connection, which in the model experiment can be represented as a bundle of several relations (4÷6). Then the prepared connection is mounted on a special stand, along with the force sensors tension; stretch their degrees at the same elongation Δl within the elastic strain and measure the strength of tension in the relationship. If necessary, change the stiffness characteristics of communication, adding or removing a portion of the filaments in the bundle.

In the process of model testing direct measurements determine the tension force in the anchor links, angular and linear models. Global forces and moments acting on the model are determined by calculation. In the basis of calculation based on the algorithm for solving a nonlinear system of equations of equilibrium of an object during joint movement and deformation is inhomogeneous on the length of the anchor links. The length of each link in the current time is determined by the known coordinates of the respective anchor points and the computed coordinates (according to the measurement of linear and angular displacements of the model) kluczowych the points of attachment of the anchor links to the model.

The above algorithm to solve the nonlinear system of equations for the determination of the global forces and moments is implemented in the corresponding DL program the computer. The initial data for calculations of the program are:

- inertial-mass properties model;

geometrical parameters of the anchored system at the initial moment of time (including the coordinates of the center of gravity coordinates of the anchor and kluczowych points, and the points of the platform, which is measured move);

components of the matrix damping anchored system;

- temporary account changes in the three coordinates of the measured points and angles of roll, pitch, yaw model;

- temporary record change efforts tension ties;

- stiffness characteristics mediamonitoring links.

The output of the program are issued restored implementation in time all six component of the global ice load.

The essence of the invention is illustrated by drawings, where figure 1 shows a device for implementing the method of testing models of marine engineering structures with anchor restraint system in the model tank; figure 2 - the same device, side view; figure 3 is a photograph prepared to test the model in the field of continuous simulated ice (with the technological cart on the model).

Device for testing models of marine engineering structures in ice model tank contains (1) channel 1 is filled with water, on the surface of which is formed ice is field 2, tow truck 3 with the drive and running wheels in contact with the rails 4 are laid along the channel, the speed sensor tow truck 5, bulldozer 6, removable metal farm 7 fixedly connected to the bottom of the channel, model engineering structures 8 which is provided with anchor links 9, by which it is fixed on the farm, dynamometers tension force in the links 10, the adjusting device connection on the specified initial tension of 11 (figure 2). Farm 7 includes a flat base 12, vertical posts 13, the blocks 14. The base farm 12 is equipped with a device mounting uprights 13 with the possibility of their installation in the set points of the base (not shown). The upright support 13 is provided blocks and device mounting 14 with the possibility of mixing height along the racks and fixing in a predetermined position. Model 8 includes gyroscopically sensors its angular movements (roll, pitch, yaw) 15 and is connected by flexible connections with precision potentiometric sensors 16, 17 linear model in the direction of the axes X, Y, Z. the Outputs of the load cells tension anchor links 10, rotary sensors 15 and sensors linear models 16, 17 are connected with the input of the computer (PC and lines of communication with her dynamometers and sensors not shown).

The offer is tion method and the device are as follows.

Choose the scale of the model, calculate and pick up the weight and dimensions of the model, the position of the center of gravity and moments of inertia with respect to axes X, Y, Z model.

Identify and select anchor connection 9, providing dynamic similarity in situ anchor links. Equip anchor link dynamometers tension force and determine on a special stand stiffness characteristics of the link. On the technological flooring laid over the channel of the water tank, install a removable metal farm 7 with vertical posts 13 and the blocks 24. The upright support 13 is installed in the specified (estimated) points to the base 12 of the farm and fix them motionless. Blocks 14, mounted on the vertical posts 13, set at a given height and fixed in this position. Hung hoist on farm 7 model marine engineering structures 8. Fix in kluczowych points of the model anchor connection 9, is equipped with dynamometers tension force 10, pass them through a respective blocks 14 on the base farm 12 and the vertical posts 13 and output along the sides of the channel of the water tank. Raise farm 7 on technological flooring. Apart technological flooring. Lower metal farm 7 on the bottom of the channel of the water tank and connected with it by anchor links 9 model 8, neatly Podravina the ends of acorn the x links 9. Connect the ends of the anchor ties with the adjusting device connection on the specified initial tension 11, the opposite ends of which are fixedly mounted on the sides of the channel of the water tank. Set on the model 8 rotary sensors 1-5. Pull the technological cart (see figure 3) with the sensors 16, 17 linear movement so that it is located above the test model 8. Connect the model 8 flexible connections with the sensors 16, 17. The cables from the sensors 15, 16, 17 and dynamometers tension force 10 laid inside the test model 8, display technology cart and then to a workplace of the operator. Connect the cables of the load cells and sensors of angular and linear displacements of transformative equipment and computers. Regulate by means of a device 11 initial tension in anchor links 9. controlling it on the computer. The device is ready for testing.

Must be the ice field 2. Measure its physical-mechanical characteristics. Check and if necessary adjust the initial tension of the anchor links 9. Set the movement towing carriage 3 with a given velocity V0and pull with bulldozer 6 ice field 2 on the test model, by registering on the computer of the tension force in the anchor links, angular and linear displacement model 8. Process the test results and determine Aut global forces and moments, acting on the test model structures.

1. The method of testing models of marine engineering structures in ice model tank, which consists in the fact that the model is fixed on the dynamometer in the channel of the water tank, must be an ice field or prepare hummocky the formation of fragments of ice, pull with bulldozer towing truck received ice formation on the test model and measure the current on the model of the global forces and moments, characterized in that the model performs dynamically similar marine engineering construction on weight and size characteristics, the position of the center of gravity and moments of inertia with respect to axes X, Y, Z model before testing the model structures provide anchor restraint system, consolidation model in the channel of the water tank passes through equipped with dynamometers force of the tension anchor link that is chosen dynamically similar field object, for which pre-determine and pick up a special booth stiffness characteristics mentioned anchor links, and in the process slipped on easily on the tested model of ice formation measure angular and linear displacement model and anchor links - tension force, and the global forces and moments acting on the model, determine raschet the m by the relations

where m is the mass of the model structures with regard to added masses of water;

rGis the radius vector of the center of gravity in the associated coordinate system;

the inertia tensor structures (including attached moments of inertia and static moments);

the vector of linear speed of the pole associated coordinate system;

the vector of angular velocity of the pole associated coordinate system;

- the main vector of external forces;

the main moment of external forces about the pole of the associated coordinate system.

2. Device for testing models of marine engineering structures in ice model tank containing a channel filled with water on the surface of which is formed ice box, removable metal farm fixedly connected to the bottom of the channel, a tow Dolly with electric drive and running wheels in contact with the rails laid along the channel, and is equipped with a bulldozer to move the ice field, the speed sensor tow truck, torque and registration apparatus, characterized in that the model is equipped with anchor St is same, by which it is fixed on the farm, anchor link is equipped with dynamometers tension force and the adjusting device connection on the specified initial tension and made uniform in length, farm includes a flat horizontal base, vertical posts and blocks, and the basis of the farm is equipped with a device mounting uprights can be installed in specific points of the base, and the upright is equipped with modules and devices attaching them with the opportunity to offset their height along the racks and fixing in a predetermined position, and the model is equipped with sensors of its angular and linear displacement in the direction of the axes X, Y, Z, outputs dynamometers force of the tension anchor links, sensors, angular and linear displacements of the model is connected with the input of the computer.



 

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