CN104155131A - Cable simulation device and cable simulation method in ship mooring physical model test - Google Patents

Abstract

The invention discloses a cable simulation device and a cable simulation method in a ship mooring physical model test. The cable simulation device comprises a box body, wherein tracks, spring systems, as well as a fixed plate and a tension plate which are horizontally arranged in parallel up and down, are arranged inside the box body; the tension plate can slide up and down along the tracks; the spring systems comprise a plurality of springs and connection pull rods which are different in lengths; the cable simulation method comprises the following steps: according to stress deformation characteristics of a cable to be simulated, the length of each spring and the length of each pull rod are calculated and determined, so as to constitute the spring systems and to keep connection with the tension plate; graded pulling forces are exerted; corresponding elongation of the tension plate is measured; through the spring systems with various lengths, nonlinear tension-elongation relation of the cable is simulated and the tension-elongation relation curves are drawn; the tension-elongation relation curves are compared with the stress deformation theoretical curves of the simulated cable; errors of the test results are checked. The cable simulation device provided by the invention solves technical problem of nonlinear load and deformation relation simulation of the cable in a ship mooring physical model test; the operability is good; the accuracy and the efficiency are high; the experimental effects are favorable.

Description

Cable simulation device and method for ship mooring physical model test

technical field

The invention belongs to the technical field of water transportation engineering, and relates to a ship mooring physical model test device and method suitable for coast, offshore and inland waters, in particular to a cable simulation device and method for ship mooring physical model test.

Background technique

With the development of economic globalization, shipping has occupied a supporting position in the long-distance transportation market with its unique advantages of economy, efficiency, safety and environmental protection. The booming development of the shipping industry has brought unprecedented opportunities for large-scale ships and deep-water terminals. It also poses new challenges to the requirements of port construction. Along with the rapid development of large berths, it often occurs that the mooring cables of large ships break under the effects of wind, waves, tides, etc., causing serious accidents. The force on the mooring ship's cable in front of the wharf has a very complicated relationship with the ship's motion. It not only involves the nonlinear constraints on the ship such as fenders and mooring force, but also involves the effects of wind, water flow and waves. The berth layout scheme of the specific wharf, such as the length of the wharf, the structural layout, etc., will also directly affect the distribution of the mooring force of the ship. Among them, the arrangement, quantity, initial tension and material type of mooring cables will have an important impact on the safety and normal operation of ships and wharf structures. As mentioned above, due to the variety of external loads on the ship, the force on the cable is very complicated. Therefore, it is often necessary to verify and optimize the design of the dock berth and mooring ship cable force through the method of ship mooring physical model test. The stress and deformation characteristics of the cable are related to its length, diameter, material and other factors, showing obvious nonlinear characteristics.

In the currently commonly used ship mooring physical model test, it is impossible to simulate the nonlinear relationship between the tension and deformation of the cable. The simulation of the elastic modulus of the cable is mainly considered. Generally, materials with similar deformation are found, such as reduced steel wire ropes and nylon wires. In the experiment, the tension and deformation of the cable should be considered separately, and multiple experiments are required. The operability and accuracy are poor, the test efficiency is low, and the test effect is poor.

Contents of the invention

In order to overcome the above-mentioned defects in the prior art, the technical problem to be solved by the present invention is to propose a ship mooring physics system that can perform nonlinear tensile deformation simulation tests of cables, has good operability, high accuracy and efficiency, and good test results. Cable simulation device and its method in model test.

The technical purpose of the present invention is achieved in that a cable simulation device in a ship mooring physical model test includes a box, and is characterized in that:

A track, a spring system, a fixed plate and a tension plate arranged horizontally up and down and parallel to each other are arranged in the box, and the tension plate can slide up and down along the track;

The fixed plate is provided with several upper plate holes, and the tension plate is provided with several lower plate holes, the number of the upper plate holes and the lower plate holes is equal, each hole corresponds up and down, and the up and down corresponding holes The vertical projections of the center of the circle coincide;

The spring system is composed of several springs equal to the number of holes in the lower plate, and the upper ends of the springs are rigidly connected with pull rods; the pull rods are slidably passed through the holes in the upper plate of the fixed plate; The lower end passes through the lower plate hole of the tension plate to keep free;

A vertically upward fixing rod is arranged at the center of the upper surface of the fixing plate; a downwardly extending flexible member is arranged at the center of the lower surface of the tension plate.

The fixed plate is rigidly connected to the inner wall of the box; the lower surface of the fixed plate is in contact with the upper end of the track.

The rigid coefficients of the springs are the same; the diameter of the springs is at least not greater than the diameter of the lower plate hole of the tension plate.

The pull rod is marked with a length scale; the diameter of the pull rod is at least not larger than the diameter of the upper plate hole of the fixed plate; a limit nut is provided on a free section of the pull rod away from the spring.

The track is marked with the same standard length scale as the pull rod; the track is provided with a limiter.

Set screws are arranged in the lower plate hole of the tension plate.

The end of the fixed rod far away from the center of the fixed plate is fixed at the test point; the fixed rod is at least a rigid rod with high tensile and compressive strength made of steel, copper, or rubber.

A tensile load is applied to the end of the flexible member away from the center of the tension plate; the flexible member is at least a high-tensile-strength flexible rope made of steel wire rope or polymer nylon rope.

The horizontal section of the box body is one of circular, square or rectangular.

A cable simulation method in a ship mooring physical model test of the present invention is characterized in that using the above-mentioned device comprises the following steps:

(1) According to the load and deformation characteristics of the prototype cable and the design of the physical model test, determine the load and deformation characteristic curve of the cable to be simulated in the model test, and select several points as the simulation control points (P _i , S _i ) _{i=1,... ,n} , P _i is the tensile load corresponding to each control point, S _i is the elongation corresponding to each control point, and n is the number of simulated control points.

(2) Using the formula $P_i=(\frac{S_i}{L_1}+\frac{S_i-S_1}{L_2}+......+\frac{S_i-S_{i-1}}{L_i})\·{K,}_{(i=1,...,\mathrm{no})},$ Calculate and determine the length L _i of each spring, K is the spring stiffness coefficient, and the number of springs is n, corresponding to the number of simulation control points one by one.

(3) According to the calculated length L ₁ of the first spring, close the limiter on the track, limit the position of the tension plate, loosen the limit nut on the pull rod corresponding to the first spring, and adjust the pull rod so that the fixed plate and The length of the first spring between the tension plates is L ₁ , tighten the corresponding positioning screw on the tension plate to fix one end of the first spring, and adjust the position of the corresponding limit nut on the pull rod connected to the spring to ensure that the limit nut and the fixed The distance between the plates is zero, then tighten the limit nuts.

(4) According to the calculated length L _i of the i-th spring, loosen the limit nut on the pull rod corresponding to the i-th spring, and adjust the pull rod so that the length of the i-th spring between the fixed plate and the tension plate is L _i , tighten the corresponding positioning screw on the tension plate to fix one end of the i-th spring, tighten the corresponding limit nut on the pull rod connected to the spring, adjust the position of the corresponding limit nut on the pull rod connected to the spring, and ensure that the limit nut and the fixed The distance between the plates is S _i-1 , then tighten the limit nuts; repeat the above steps until all n springs are set, then open the limiters on each track so that the tension plates can slide along the track.

(5) Connect one end of the simulation device to the test point through a fixed rod, and apply a tensile load in stages on the end of the flexible part far away from the center of the tension plate. The displacement value of the pull-down force plate;

(6) Draw the tension-elongation curve according to the tension values at all levels and the corresponding displacement values, compare it with the theoretical curve of the force deformation of the cable to be simulated, and check the error of the simulation results.

Concrete advantage and effect of the present invention are:

(1) The lengths of different springs can be directly calculated and determined according to theoretical formulas, which has a high degree of theory and reduces the requirements for the operator's test experience.

(2) According to the calculation results, limit nuts are used to constrain each tie rod respectively, so that springs of different numbers and lengths can participate in bearing the tension load under the action of tension at all levels.

(3) Positioning screws are set at each opening of the tension plate to limit the expansion and contraction of the spring, and cooperate with the upper limit nut of the pull rod to adjust the length of each spring according to the calculation result.

(4) A plurality of rails are arranged in the device box, and the tension plate slides along the rails under the action of tension, so as to ensure that the spring group can bear the force as a whole, and also ensure that the direction of the tension action is consistent with the deformation direction of the spring.

(5) Set a limiter on the track to temporarily limit the tension plate when debugging the instrument.

(6) A spring group composed of several springs is arranged between the fixed plate and the tension plate, and holes are provided at the corresponding positions of the fixed plate and the tension plate. The number of springs required in the test can be determined according to the number of simulated control points.

In a word, the cable simulation device and the method thereof in the ship mooring physical model test described in the present invention can carry out the nonlinear tensile deformation simulation test of the cable, with good operability, high accuracy and efficiency, and good test effect.

Description of drawings

Fig. 1 is a structural schematic diagram of a cable simulation device in a ship mooring physical model test of the present invention, in which there are 12 springs.

FIG. 2 is a top view of FIG. 1 .

Fig. 3 is a flowchart of a cable simulation method in a ship mooring physical model test of the present invention.

Fig. 4 is a load-deformation characteristic curve of the cable to be simulated by the cable simulation method in the ship mooring physical model test of the present invention, wherein the number of simulation control points, that is, the number of springs, is 12.

In the figure, 1 box body, 2 fixed plate, 21 upper plate hole, 3 track, 4 tension plate, 41 lower plate hole, 5 limit nut, 6 pull rod, 7 positioning screw, 8 spring system, 81 spring, 9 flexible parts , 10 setscrews, 11 fixed rods, 12 limiters, 13 test points, 14 tensile loads.

Specific embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings.

Detailed ways

A cable simulation device in a ship mooring physical model test of the present invention comprises a box body (1), and is characterized in that:

A track (3), a spring system (8), a fixed plate (2) and a tension plate (4) arranged horizontally up and down and parallel to each other are arranged in the box body (1). The tension plate (4) can be moved along the track (3) Slide up and down;

The fixed plate (2) is provided with several upper plate holes (21), the described tension plate (4) is provided with several lower plate holes (41), and the described upper plate holes (21) and the lower plate The number of holes (41) is equal, each hole corresponds up and down, and the vertical projections of the centers of the corresponding holes up and down coincide;

The spring system (8) is composed of several springs (81) equal in number to the lower plate holes (41), and the upper end of the springs (81) is rigidly connected with a pull rod (6); the pull rod (6) slidably pass in the upper plate hole (21) of the fixed plate (2); the lower end of the spring (81) passes through the lower plate hole (41) of the tension plate (4) and remains free;

A vertically upward fixing rod (11) is arranged at the center of the upper surface of the fixing plate (2); and a downwardly extending flexible piece (9) is arranged at the center of the lower surface of the tension plate (4).

The fixed plate (2) is rigidly connected to the inner wall of the box body (1); the lower surface of the fixed plate (2) is in contact with the upper end of the track (3).

Described spring system (8) is made up of many springs (81) and pull rod (6) of different lengths; The rigidity coefficient of described spring (81) is identical, and direction keeps parallel, and tension load (14) The direction of action is consistent, and is kept perpendicular to the fixed plate (2) and the tension plate (4). The diameter of the spring (81) is at least not greater than the diameter of the lower plate hole (41) of the tension plate (4). Calculate and determine the lengths of each (81) and the pull rod (6) according to the stress-deformation characteristics of the cable to be simulated.

The described pull rod (6) is marked with a length scale such as a millimeter scale; the diameter of the pull rod (6) is at least not greater than the diameter of the upper plate hole (21) of the fixed plate (2); the pull rod (6) is far away from the spring (81) A limit nut (5) is provided on a free section. Adjust the stop nut (5) to adjust the length of the free section of each pull rod (6) and ensure that the other end of the spring (81) is well connected with the fixed plate (2).

The direction of action of the tension load (14) of described track direction and spring system (8) is consistent; The length scale that is marked with pull bar (6) identical unit on the track (3) is as millimeter scale; Set on the track (3) There is a limiter (12), which is used to temporarily limit the position of the tension plate (4) when debugging the instrument.

A positioning screw (7) is arranged in the lower plate hole (41) of the tension plate (4). Adjust the set screw (7), the length of each spring (81) can be adjusted and ensure that one end of the spring (81) is well connected with the tension plate (4). Tighten the set screw (7), the spring (81) is fixed at the lower plate hole (41), loosen the set screw (7), and the spring (81) moves freely in the lower plate hole (41).

One end of the fixed rod (11) away from the center of the fixed plate (2) is fixed on the test point (13); the tensile deformation of the fixed rod (11) itself under the action of tension and pressure should be negligible. The fixed rod (11) is at least a rigid rod member with high tensile and compressive strength made of materials such as steel, copper, or rubber.

A tensile load (14) is applied to the end of the flexible member (9) far away from the center of the tension plate (4); the tensile deformation of the flexible member (9) itself under the action of tension should be negligible. The flexible part (9) is at least a kind of flexible rope with high tensile strength made of materials such as steel wire rope or polymer nylon rope. Through the flexible member (9), the tension load (14) can be applied in stages, and the corresponding movement elongation of the tension plate (4) can be measured to obtain a tension-elongation relationship curve.

The horizontal section of the box body (1) is one of circular, square or rectangular.

A cable simulation method in a ship mooring physical model test of the present invention is characterized in that the above-mentioned device comprises the following steps:

(1) According to the load and deformation characteristics of the prototype cable and the design of the physical model test, determine the load and deformation characteristic curve of the cable to be simulated in the model test, and select several points as the simulation control points (P _i , S _i ) _{i=1,... ,n} , P _i is the tensile load (14) corresponding to each control point, S _i is the elongation corresponding to each control point, n is the number of simulated control points;

(2) Using the formula $P_i=(\frac{S_i}{L_1}+\frac{S_i-S_1}{L_2}+......+\frac{S_i-S_{i-1}}{L_i})\&Center\; Dot;{K,}_{(i=1,...,\mathrm{no})},$ Calculate and determine the length L _i of each spring (81), K is the spring stiffness coefficient, and the number of springs (81) is n, that is, the number of control points of the curve to be simulated. The number of springs is in one-to-one correspondence with the number of simulation control points. Theoretically speaking, the larger N is, the more accurate the simulation will be. In actual tests, the value of N is generally determined according to the theoretical curve of deformation of the cable and the test accuracy. Usually, N is 5-8.

(3) According to the calculated length L ₁ of the first spring (81), close the limiter (12) on the track (3), limit the position of the tension plate (4), and relax corresponding to the first spring (81) The limit nut (5) on the tie rod (6) is adjusted so that the length of the first spring (81) between the fixed plate (2) and the tension plate (4) is L ₁ , and the tension plate is tightened (4) Fix one end of the first spring (81) with the corresponding positioning screw (7), adjust the position of the corresponding limit nut (5) on the pull rod (6) connected to the spring (81), to ensure that the limit nut ( 5) The distance to the fixed plate (2) is zero, then tighten the limit nut (5);

(4) According to the calculated length L _i of the i-th spring (81), loosen the limit nut (5) on the pull rod (6) corresponding to the i-th spring (81), and fix it by adjusting the pull rod (6). The length of the i-th spring (81) between the plate (2) and the tension plate (4) is L _i , tighten the corresponding set screw (7) on the tension plate (4) to fix one end of the i-th spring (81), tighten Corresponding limit nut (5) on the pull bar (6) that links to each other with this spring (81), adjust the position of corresponding limit nut (5) on the pull bar (6) that links to each other with this spring (81), ensure that limit nut ( 5) The distance from the fixed plate (2) is S _i-1 , then tighten the limit nut (5); repeat the above steps until all n springs (81) are set, and then open the The limiter (12) makes the tension plate (4) slide along the track (3).

(5) One end of the simulation device is connected to the test point (13) through the fixed rod (11), and the tensile load (14) is applied in stages at the end of the flexible member (9) away from the center of the tension plate (4), and the tensile load ( 14) The direction of action should be kept perpendicular to the tension plate (4), and the displacement values of the tension plate (4) under the action of the tension loads (14) at all levels should be recorded;

(6) Draw the tension-elongation curve according to the tension values at all levels and the corresponding displacement values, compare it with the theoretical curve of the force deformation of the cable to be simulated, and check the error of the simulation results.

Claims (10)

1. a hawser analogue means in ship mooring physical experiments, comprises casing (1), it is characterized in that:

In casing (1), be provided with track (3), spring system (8) and fixed head (2), tension board (4) upper and lower horizontally disposed and that be parallel to each other, described tension board (4) can slide up and down along track (3);

Described fixed head (2) is provided with several upper plate holes (21), described tension board (4) is provided with several lower plate holes (41), described upper plate hole (21) and the quantity of lower plate hole (41) equate, each hole is corresponding up and down, and the vertical projection in the center of circle of upper and lower corresponding aperture coincides;

Described spring system (8) is made up of the several springs (81) that equate with the quantity of lower plate hole (41), and the upper end rigid connecting of described spring (81) is connected to pull bar (6); Described pull bar (6) is slidably through in the upper plate hole (21) of fixed head (2); The lower end of spring (81) keeps freely through the lower plate hole (41) of tension board (4);

Described fixed head (2) upper surface center is provided with a fixed bar (11) straight up; Described tension board (4) lower surface center is provided with a flexible piece to downward-extension (9).

2. hawser analogue means in a kind of ship mooring physical experiments according to claim 1, is characterized in that: described fixed head (2) is rigidly connected on casing (1) inwall; The lower surface of fixed head (2) contacts with the upper end of track (3).

3. hawser analogue means in a kind of ship mooring physical experiments according to claim 1, is characterized in that: the stiffness coefficient of described spring (81) is identical; The diameter of spring (81) is at least not more than the diameter of the lower plate hole (41) of tension board (4).

4. hawser analogue means in a kind of ship mooring physical experiments according to claim 1, is characterized in that: described pull bar (6) is marked with length scale; The diameter of pull bar (6) is at least not more than the diameter of the upper plate hole (21) of fixed head (2); A free segment away from spring (81) of pull bar (6) is provided with stop nut (5).

5. hawser analogue means in a kind of ship mooring physical experiments according to claim 1, is characterized in that: described track (3) is marked with the length scale with pull bar (6) identical standard; Track (3) is provided with stop (12).

6. hawser analogue means in a kind of ship mooring physical experiments according to claim 1, is characterized in that: in the lower plate hole (41) of described tension board (4), be provided with set screw (7).

7. hawser analogue means in a kind of ship mooring physical experiments according to claim 1, is characterized in that: testing site (13) is fixed in one end away from fixed head (2) center of circle of described fixed bar (11); Fixed bar (11) is at least a kind of high tensile of the materials such as steel, copper or rubber and the rigid bar of Compressive Strength.

8. hawser analogue means in a kind of ship mooring physical experiments according to claim 1, is characterized in that: one end away from tension board (4) circle centre position of described flexible piece (9) is applied with pulling force load (14); Flexible piece (9) is at least the high-tensile flexible rope of one of the material such as wire rope or macromolecule nylon rope.

9. hawser analogue means in a kind of ship mooring physical experiments according to claim 1, is characterized in that: the horizontal cross-section of described casing (1) is the one of circle, square or rectangle.

10. a hawser analogy method in ship mooring physical experiments, is characterized in that, right to use requires the device described in 1 to 9, comprises the following steps:

(1) according to the loaded deformation characteristic of prototype hawser and physical experiments design, determine hawser loaded deformation family curve to be simulated in model test, and choose some as simulation reference mark (P _i, S _i) _{i=1 ..., n}, P _ifor pulling force load (14) corresponding to each reference mark, S _ifor elongation corresponding to each reference mark, n is simulation reference mark number;

(2) adopt formula $P_i=(\frac{S_i}{L_1}+\frac{S_i-S_1}{L_2}+......+\frac{S_i-S_{i-1}}{L_i})\·{K,}_{(i=1,...,n)},$ The length L of every spring of calculative determination (81) _i, K is spring rate, the quantity of spring (81) is n, counts corresponding one by one with simulation control;

(3) according to calculating first spring of gained (81) length L ₁close the stop (12) on closed orbit (3), limit tension board (4) position, loosen the stop nut (5) on the pull bar (6) corresponding with first spring (81), making first spring (81) length between fixed head (2) and tension board (4) by adjusting yoke (6) is L ₁tighten the upper corresponding set screw (7) of tension board (4) and fix one end of first spring (81), regulate the position of the upper corresponding stop nut (5) of pull bar (6) being connected with this spring (81), guarantee that the distance between stop nut (5) and fixed head (2) is zero, then tighten stop nut (5);

(4) according to calculating gained i root spring (81) length L _iloosen the stop nut (5) on the pull bar (6) corresponding with i root spring (81), making i root spring (81) length between fixed head (2) and tension board (4) by adjusting yoke (6) is L _itighten the upper corresponding set screw (7) of tension board (4) and fix one end of i root spring (81), tighten the upper corresponding stop nut (5) of the pull bar (6) being connected with this spring (81), regulate the position of the upper corresponding stop nut (5) of pull bar (6) being connected with this spring (81), guarantee that the distance between stop nut (5) and fixed head (2) is S _i-1, then tighten stop nut (5); Repeat above-mentioned steps, arrange after all n root springs (81) until complete, open the stop (12) on each track (3), tension board (4) can be slided along track (3).

(5) one end of analogue means is connected with testing site (13) by fixed bar (11), one end classification away from tension board (4) circle centre position at flexible piece (9) applies pulling force load (14), pulling force load (14) action direction should keep vertical with tension board (4), and records the shift value of pulling force loads at different levels (14) effect lower pulling force plates (4);

(6) according to values of thrust at different levels and corresponding shift value, draw pulling force-elongation curve, contrast with cable stress Deformation Theory curve to be simulated, and check analog result error.