CN116519261B - Floating offshore platform free attenuation test device, method and application - Google Patents

Abstract

The floating type offshore platform free damping test device comprises a fixed frame, a base plate, an electromagnet, an adjusting device, an electromagnet sucker, an air flotation slide block, an optical axis, a guide rod, a guide part, a displacement sensor and an upper computer, wherein the guide rod is connected to the lower end of the air flotation slide block, the lower end of the guide rod is fixedly used for fixing a floating platform test member, the air flotation slide block moves in a vertical free damping mode along a first optical axis and a second optical axis by virtue of the air flotation slide block, the guide rod and the fixed floating platform test member move in the vertical free damping mode along the first optical axis and the second optical axis by virtue of the air flotation slide block, and the effect is that the drawing accuracy of a vertical free damping curve drawn by collecting displacement data is synergistically improved.

Description

Floating offshore platform free attenuation test device, method and application

Technical field

The invention belongs to the technical field of marine engineering, and in particular relates to a free attenuation physical model test device for free attenuation model testing of a single degree of freedom of a floating ocean platform.

Background technique

Floating offshore platforms are an indispensable technology for exploring deep-sea oil and gas resources and renewable energy. For example, semi-submersible floating drilling platforms are used to develop deep-sea oil and gas resources, and floating offshore wind turbine platforms are used to develop deep-sea wind power. Correctly understanding the structural characteristics of floating offshore platforms is of great significance for improving the efficiency of marine resource detection and reducing economic costs.

During the design and development process of floating offshore platform structures, the economics and reliability of the structure are mainly verified through numerical simulations and physical model tests. Usually, the dynamic response of the floating offshore platform is analyzed through numerical simulation, and then the pool physical model test is carried out to verify the reliability of the numerical model. Physical model tests generally include: static water attenuation test, seakeeping test and combined wind and wave test, etc. The hydrostatic attenuation test is directly related to the rationality of the structure's own characteristics, including the basic frequency of the structure and structural damping. Therefore, the success or failure of the still water free attenuation test is of great significance to the design of floating offshore platforms.

The main principle of the static water free attenuation test is: in the early stage of the test, a certain initial displacement or load is given to the test object to cause the floating structure to deviate from the original equilibrium position. When the water surface stabilizes, the floating structure is instantly released. Subsequently, the floating offshore platform will oscillate regularly on the water until it decays. During the free attenuation process, the motion time history curve in the direction of the degree of freedom is obtained through the motion monitored by the motion measurement system. Finally, by analyzing the motion history curve, the vibration period and damping of the result can be obtained.

At present, the free attenuation test method for floating offshore platforms based on physical model testing has not yet formed a system, and a complete test method has not yet guided the actual free attenuation work. The usual method is: the experimenter stands in the water, adds weights or artificially presses to make the floating structure deviate from the original equilibrium position, and then completes free attenuation by removing the weights or releasing the arms.

This method has great limitations. The free attenuation curve obtained by this method usually has more noise and low accuracy. Its main shortcomings are: 1. During the manual pressing process, a certain initial value cannot be given. An accurate comparison with numerical simulation results cannot be made. 2. When the scale of the floating structure is large, it is difficult to make the structure deviate from the original equilibrium position and achieve stability through human operation, and it is difficult to achieve free attenuation of the floating structure. 3. When manually pressing or adding heavy objects, the tester usually needs to be in the water. During the release process, the tester needs to stay in the water. During the free decay process of the structure, people in the water interfere with the flow field around the structure, affecting the accuracy of the physical model test. 4. When the water depth is deep and people cannot stand in the water, it is more difficult to carry out free attenuation physical model tests. 5. The ideal state of the free attenuation test is that the structure only oscillates attenuated in the direction of a single degree of freedom. Otherwise, it will be coupled with the motion of other degrees of freedom of the structure, which will greatly affect the accuracy of the free attenuation. However, the artificial pressing method cannot ensure that the floating body structure oscillates and attenuates in the direction of single degree of freedom.

The existing floating offshore platform free attenuation test device basically adopts the loading and unloading structure of the fixed floating platform test component. During the loading and unloading process, the movement of the fixed floating platform test component is a free movement with multiple degrees of freedom. Coupling, for the one-way degree of freedom attenuation test, this loading and unloading structure has no way to limit the coupling to other degrees of freedom, which greatly reduces the drawing of the free attenuation curve of the one-way degree of freedom, making it difficult to draw the curve accurately. For the one-way degree-of-freedom attenuation test, the important vertical degree-of-freedom attenuation test requires an accurate free attenuation curve to accurately analyze the operating characteristics of the floating offshore platform.

Contents of the invention

In order to solve the problem of free attenuation test device with basically no coupling of other degrees of freedom in the vertical degree of freedom attenuation test, and to be closer to the ideal zero friction, simulate the problem of free attenuation of the floating structure in the water without other external friction. , In a first aspect, a floating offshore platform free attenuation test device according to some embodiments of the present application includes

a base plate, which is arranged vertically;

An electromagnet, the electromagnet is arranged on the surface of the substrate;

The adjusting device includes a nut and a bolt. The nut is arranged on the upper part of one side of the base plate. The bolt cooperates with the nut. The electromagnet is connected to the lower end of the bolt. The bolt and the nut cooperate to move the bolt in the vertical direction, so that the electromagnet can move in the vertical direction to change the initial position of the free attenuation test in the vertical direction;

Electromagnet suction cup, the electromagnet suction cup is correspondingly arranged below the electromagnet. Before the start of the free attenuation test, the electromagnet suction cup is attracted to the electromagnet in the vertical initial position. When the free attenuation test begins, the electromagnet suction cup is disconnected from the electromagnet at the vertical initial position;

Air flotation slider, the electromagnet suction cup is arranged on the air flotation slider, the air flotation slider includes a first through hole and a second through hole arranged laterally along the substrate, the electromagnet suction cup is provided The upper surface of the air-bearing slider between the first through-hole and the second through-hole;

Optical axis, the optical axis is axially arranged in the vertical direction and the optical axis is arranged on the base plate, the optical axis cooperates with the air-floating slider to guide the air-floating slider to the position where the air-floating slider is positioned The vertical movement, the optical axis includes a first optical axis and a second optical axis, the first optical axis cooperates with the first through hole of the air bearing slider in the vertical direction, and the third optical axis The two optical axes cooperate with the second through hole of the air bearing slider in the vertical direction, and there is a first gap between the first optical axis and the first through hole that cooperates with the first optical axis. The first gap is the vertical gap between the peripheral surface of the first optical axis and the inner wall of the first through hole, and high-pressure gas flows through the first through hole of the air bearing slider, There is a second gap between the second optical axis and the second through hole matching the second optical axis, and the second gap is the position between the peripheral surface of the second optical axis and the inner wall of the second through hole. The vertical gap is provided, and high-pressure gas flows through the second through hole of the air-bearing slider, and the electromagnet chuck is disposed on the center between the first optical axis and the second optical axis. The upper surface of the air-floating slider is disconnected by the electromagnet suction cup and the electromagnet. The air-floating slider moves in the vertical direction along the first optical axis and the second optical axis. Free attenuation movement, and the first gap is maintained between the first optical axis and the first through hole matching the first optical axis, the second optical axis and the third optical axis matching the second optical axis The second gap is maintained between the two through holes;

Guide rod, the guide rod is connected to the lower end of the air flotation slider, and the lower end of the guide rod fixes the floating platform test component. The air flotation slider moves along the first optical axis and the second optical axis. The shaft is free to attenuate movement in the vertical direction, and the guide rod and the fixed floating platform test member follow the air-floating slider to move freely in the vertical direction along the first optical axis and the second optical axis;

A displacement sensor that collects displacement data of the movement of the air-bearing slider in real time;

The upper computer receives the displacement data of the movement of the air-floating slider collected by the displacement sensor, and draws the free attenuation curve of the fixed floating platform test component based on the displacement data.

According to the free attenuation test device of a floating offshore platform in some embodiments of the present application, air outlets are evenly spaced on the circumference of the inner walls of the first through-hole and the second through-hole, and the air float is supplied to the air float through the air compressor. High-pressure gas is introduced into the interior of the slider, and the high-pressure gas is evenly distributed around the first through-hole and the second through-hole through the air channel.

The floating offshore platform free attenuation test device according to some embodiments of the present application also includes

Fixed frame, the fixed frame is a frame of rectangular structure, the first cross beam on the upper part of one side of the fixed frame is connected to the base plate, and the lower part of the fixed frame on one side is opposite to the upper cross beam. The second cross member is connected to the two lower side cross members in the middle of the axial direction;

The front and back thread bolts include a first front and back thread bolt and a second front and back thread bolt. One end of the first front and back thread bolt is fixed on the first beam, and the other end is fixed on the upper end surface of the base plate. One end of the second front and back thread bolt is fixed on the first cross beam, and the other end is fixed on the upper end surface of the base plate. The first front and back thread bolts and the second front and back thread bolts are arranged on the base plate in a transverse direction. both ends of the upper end surface.

According to some embodiments of the floating offshore platform free attenuation test device of the present application, the optical axis is fixed on one side of the base plate by the fixing block, and the fixing block includes a first upper fixing block, a first A lower fixing block, a second upper fixing block and a second lower fixing block. The first upper fixing block and the first lower fixing block are vertically opposite to each other and fixed to the vertical direction of the board surface on one side of the base plate. The second upper fixing block and the second lower fixing block are arranged oppositely in the vertical direction, and are fixed at two relative positions in the vertical direction of the board surface on one side of the base plate, and the first The upper fixing block and the second upper fixing block are arranged in two relative positions of the transverse plate surface of the base plate in the transverse direction, and the first lower fixing block and the second lower fixing block are arranged in the transverse direction of the transverse plate surface of the base plate. two relative positions, the first optical axis is fixed between the first upper fixed block and the first lower fixed block in the axial direction in the vertical direction, and the second optical axis is fixed in the axial direction in the Vertically fixed between the second upper fixed block and the second lower fixed block.

According to some embodiments of the floating offshore platform free attenuation test device of the present application, the first upper fixed block, the first lower fixed block, the second upper fixed block and the second lower fixed block extend forward from the plate surface of the base plate. A connection hole is formed in the part to connect with the optical axis, so that there is a certain distance between the optical axis and the surface of the substrate, and the first upper fixed block and the second upper fixed block limit the position of the air-floating slider. The highest movement distance in the vertical direction, the first lower fixed block and the second lower fixed block limit the lowest movement distance of the air-floating slide block in the vertical direction.

The floating offshore platform free attenuation test device according to some embodiments of the present application further includes a guide part, the guide part includes a guide hole, the guide part is provided at the bottom of the board surface of the base plate, and is formed by the plate of the base plate. The part extending forward forms the guide hole, the guide rod cooperates with the guide hole, and the diameter of the guide hole is larger than the guide rod, so that the guide is not touched during the vertical free attenuation movement. the inner wall of the hole.

According to some embodiments of the floating offshore platform free attenuation test device of the present application, the guide portion is disposed below the first lower fixing block and the second lower fixing block on the surface of the base plate, and is located in the transverse direction. Between the first lower fixed block and the second lower fixed block.

In the second aspect, according to the free attenuation test method of a floating offshore platform in some embodiments of the present application, any one of the test devices is used to implement the test method, and the test method includes the following steps:

S10. Adjust the front and back thread screws to be screwed into one end of the base plate to adjust the level of the base plate so that the level of the air-floating slider on the base plate is within the required range;

S20. The air compressor performs and maintains high-pressure inflation of the first through hole and the second through hole of the air flotation slider, so that there is a gap between the first optical axis and the first through hole matching the first optical axis. And maintain a first gap, and have and maintain a second gap between the second optical axis and the second through hole matching the second optical axis;

S30. Adjust the screw of the adjusting device so that the vertical position of the electromagnet connected to the screw is adjusted to a certain distance from the equilibrium position. Then energize the electromagnet to allow the floating platform test component to pass through the electromagnet of the air-floating slider. The suction cup is adsorbed and connected to the electromagnet, thereby causing the floating platform test component to deviate from the equilibrium position of the floating platform test component by a certain distance;

S40. When the flow field is stable, the electromagnet is powered off, and the floating platform test component disconnects from the electromagnet and moves freely, and the direction of movement is restricted by the first optical axis and the second optical axis, so that the floating platform test component The platform test component only has vertical free attenuated movement, and the displacement data of the air-floating slider movement is collected in real time by the displacement sensor until the free attenuated movement of the floating platform test component ends;

S50. Use the displacement data of the air-floating slider movement collected in real time by the displacement sensor to draw a free attenuation curve. The free attenuation curve starts from the starting position of the fixed floating platform test component at the vertical deviation from the equilibrium position. Free decay curve for free decay motion.

The free attenuation test method for floating offshore platforms according to some embodiments of the present application also includes

S60. Repeat steps S10-S50 to draw multiple sets of free attenuation curves.

In a third aspect, the application of the floating offshore platform free attenuation test device according to any one of some embodiments of the present application in the floating offshore platform free attenuation test.

Beneficial effects:

In the first aspect of the present invention, the air-bearing slider moves vertically along an optical axis with extremely low surface roughness. There is a slight gap between the optical axis and the through hole, and is arranged in a non-contact manner. However, this gap is very small. It is possible that the optical axis and the through-hole may come into contact with the wall surface when the level of the air-floating slider is not accurate enough. In the present invention, by using the air-floating slider, air outlets are evenly spaced around the inner wall of the through-hole. The air compressor injects high-pressure gas into the air-floating slider, and the high-pressure gas is evenly distributed circumferentially in the through-hole through the air channel, so that the optical axis can be corrected by the pressure of the high-pressure gas so that the optical axis does not conflict with the through-hole. The contact between the walls reduces the effect of friction on free attenuated motion.

In the second aspect, the function of high-pressure gas correction is limited. In order to form a relative motion closer to zero damping between the optical axis and the air-bearing slider, the level of the air-bearing slider needs to be within a reasonable range. Therefore, the present invention can also adjust the levelness of the linear air flotation slider by adjusting the screw-in depth of the front and back teeth, so that the levelness of the air flotation slider is within a reasonable range, so that the high-pressure gas correction function can be applicable, so that in The combination of these two methods results in a relative motion closer to zero damping between the optical axis and the air bearing slider.

In the third aspect, the guide rod is connected to the lower end of the air-floating slider, and the lower end of the guide rod fixes the floating platform test member, and the air-floating slider moves along the first optical axis and the third optical axis. The two optical axes are free to attenuate in the vertical direction, and the guide rod and the fixed floating platform test member follow the air-floating slider to freely attenuate in the vertical direction along the first optical axis and the second optical axis. In the above-mentioned relative motion that is closer to zero damping, the optical axis limiter causes the air-bearing slider to drive the fixed floating platform test component to only move in the vertical direction along the optical axis, shielding other free movements in the free attenuation. degree of influence.

In the fourth aspect, through the combination of the adjustment device, the electromagnet suction cup and the electromagnet, the initial position of the free attenuation of the floating platform can be accurately changed, avoiding the problem of low artificial pressing accuracy and affecting the flow field around the structure, thereby affecting the free attenuation accuracy. .

In the fifth aspect, the combination of various technical means of the present invention synergistically improves the drawing accuracy of the vertical free attenuation curve drawn by collecting displacement data. The corresponding experimental data is described in detail in the experimental example.

Description of the drawings

Figure 1 is a schematic structural diagram of the free attenuation test device of a floating offshore platform.

Figure 2 is the free attenuation curve obtained by the traditional model test method.

Figure 3 is a free attenuation curve obtained by the present invention.

Reference signs:

10.Substrate;

21. Electromagnet, 22. Electromagnet suction cup

31. Nut, 32. Bolt

40. Air-floating slider

51. The first optical axis, 52. The second optical axis, 53. The first upper fixed block, 54. The first lower fixed block, 55. The second upper fixed block, 56. The second lower fixed block

61. Guide rod, 62. Guide part

70. Fixed floating platform test components

80.Fixed frame

91. The first front and back thread bolt, 92. The second front and back thread bolt

Detailed ways

Embodiments of the present application are described in detail below with reference to the accompanying drawings, in which examples of the embodiments are shown, wherein the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions.

The existing floating offshore platform free attenuation test device basically adopts the loading and unloading structure of the fixed floating platform test member 70. The inventor found that during the loading and unloading process, the movement of the fixed floating platform test member 70 is a free movement with multiple characteristics. The coupling of degrees of freedom in one direction. For the one-way degree of freedom attenuation test, this loading and unloading structure has no way to limit the coupling in other degrees of freedom. This greatly reduces the drawing of the free attenuation curve of the one-way degree of freedom, resulting in the drawing of the curve. Difficult to be precise.

For the one-way degree of freedom attenuation test, the important vertical degree of freedom attenuation test requires an accurate free attenuation curve to accurately analyze the operating characteristics of the floating offshore platform. For this reason, the inventor hopes to obtain a vertical degree of freedom attenuation test that can accurately analyze the operating characteristics of the floating offshore platform. The degree-of-freedom attenuation test basically does not have a free attenuation test device coupled with other degrees of freedom, and can be closer to the ideal zero friction, simulating the free attenuation of the floating structure in the water without other external friction.

Embodiment 1: Figure 1 is a schematic structural diagram of the free attenuation test device of the floating offshore platform of the present invention. As shown in Figure 1, it includes a fixed frame 80, a base plate 10, an electromagnet 21, an adjustment device, an electromagnet suction cup 22, and an air flotation device. Slider 40, optical axis, guide rod 61, guide part 62, displacement sensor and host computer, among which:

The fixed frame 80 is a rectangular structure frame, which is mainly composed of beams and pillars. The fixed frame 80 is fixed in an environment (such as a workbench) and has high stability for suspending the base plate 10 . The upper first crossbeam on one side of the fixed frame 80 is connected to the base plate 10 , and the second crossbeam on the lower side of the fixed frame 80 that is opposite to the upper crossbeam is connected to the two lower crossbeams. The side beam is in the middle of the axis. This method can maintain the stability of the fixed frame 80 while allowing the second beam to rearwardly transfer the installation and movement position of the guide rod 61 and/or the fixed floating platform test member 70 .

The base plate 10 is arranged vertically. The base plate 10 is a vertically longer rectangular plate. The base plate 10 and the fixed frame 80 are connected by front and back thread bolts 32. The front and back thread bolts 32 include a third A front and back thread bolt 91 and a second front and back thread bolt 92. One end of the first front and back thread bolt 91 is fixed on the first beam, and the other end is fixed on the upper end surface of the base plate 10. The second front and back thread bolt 91 is One end of the reverse thread bolt 92 is fixed on the first cross beam, and the other end is fixed on the upper end surface of the base plate 10 . The first front and back thread bolts 91 and the second front and back thread bolts 92 are arranged on the base plate in a transverse direction. 10 at both ends of the upper end surface.

The electromagnet 21 is arranged on the surface of the substrate 10 . The adjustment device includes a nut 31 and a bolt 32. The nut 31 is arranged on the upper part of one side of the base plate 10. The bolt 32 cooperates with the nut 31. The electromagnet 21 is connected to the bolt. At the lower end of 32, the bolt 32 cooperates with the nut 31 to move the bolt 32 vertically, so that the electromagnet 21 can move vertically to change the initial position of the free attenuation test in the vertical direction. . Therefore, the electromagnet 21 is arranged on the plate surface of the base plate 10 through the nut 31 , and the nut 31 fixed on the plate surface of the base plate 10 extends forward from the portion of the plate surface of the base plate 10 The bolt 32 holes for installing the bolts 32 are formed so that there is a certain distance between the basic plate surface and the bolt 32 holes, thereby achieving the function of not touching moving parts.

The electromagnet sucker 22 is correspondingly arranged below the electromagnet 21. Before the free attenuation test starts, the electromagnet sucker 22 is attracted to the electromagnet 21 in the vertical initial position. When the free attenuation test begins, the electromagnet suction cup 22 is disconnected from the electromagnet 21 at the vertical initial position.

The electromagnet suction cup 22 is disposed on the air flotation slider 40 . The air flotation slider 40 includes first through holes and second through holes arranged laterally along the substrate 10 . The electromagnet suction cup 22 is disposed on the air flotation slider 40 . On the upper surface of the air slider 40 between the first through hole and the second through hole, the electromagnet chuck 22 is disposed between the first through hole and the second through hole.

The optical axis is axially arranged in the vertical direction and is arranged on the base plate 10 . The optical axis is fixed on one side of the base plate 10 by the fixing block. The fixed blocks include a first upper fixed block 53, a first lower fixed block 54, a second upper fixed block 55 and a second lower fixed block 56. The first upper fixed block 53 and the first lower fixed block 54 are vertically opposite to each other. The second upper fixing block 55 and the second lower fixing block 56 are arranged opposite to each other in the vertical direction and fixed on the two vertical positions of the board surface on one side of the base plate 10 . Two relative positions of the board surface of one side of the base plate 10 in the vertical direction, the first upper fixing block 53 and the second upper fixing block 55 are arranged laterally in two relative positions of the lateral board surface of the base plate 10, The first lower fixing block 54 and the second lower fixing block 56 are arranged in two relative positions on the transverse board surface of the base plate 10, and the first optical axis 51 is fixed in the axial direction in the vertical direction. Between the first upper fixed block 53 and the first lower fixed block 54, the second optical axis 52 is fixed in the vertical direction in the axial direction to the second upper fixed block 55 and the second lower fixed block 56. between. The first upper fixing block 53, the first lower fixing block 54, the second upper fixing block 55 and the second lower fixing block 56 form connection holes from the forward extending portions of the board surface of the base plate 10 to connect with the optical axis, There is a certain distance between the optical axis and the surface of the substrate 10 so as to avoid touching moving parts. The first upper fixed block 53 and the second upper fixed block 55 limit the maximum movement distance of the air-floating slide block 40 in the vertical direction, and the first lower fixed block 54 and the second lower fixed block 56 limit is the lowest movement distance of the air-bearing slider 40 in the vertical direction.

The optical axis cooperates with the air-bearing slider 40 to guide the air-bearing slider 40 to move in the vertical direction. The optical axis includes a first optical axis 51 and a second optical axis 52. The first optical axis The optical axis 51 cooperates with the first through hole of the air floating slider 40 in the vertical direction, and the second optical axis 52 cooperates with the second through hole of the air floating slider 40 in the vertical direction. Vertically matched, there is a first gap between the first optical axis 51 and the first through hole matching the first optical axis 51 , and the first gap is between the peripheral surface of the first optical axis 51 and the first optical axis 51 . The inner wall of a through hole is in the vertical gap, and high-pressure gas flows through the first through hole of the air bearing slider 40. The second optical axis 52 and the second optical axis 52 cooperate with each other. There is a second gap between the second through holes. The second gap is the vertical gap between the peripheral surface of the second optical axis 52 and the inner wall of the second through hole, and the air-bearing slider High-pressure gas flows through the second through hole of 40, and the electromagnet chuck 22 is disposed on the upper surface of the air-floating slider 40 between the first optical axis 51 and the second optical axis 52. By the electromagnet suction cup 22 and the electromagnet 21 being attracted and disconnected, the air-bearing slider 40 can freely move attenuated in the vertical direction along the first optical axis 51 and the second optical axis 52 , and the first gap is maintained between the first optical axis 51 and the first through hole that cooperates with the first optical axis 51 , and the second optical axis 52 and the first through hole that cooperates with the second optical axis 52 The second gap is maintained between the second through holes. Air outlets are provided at even intervals on the circumferential surfaces of the inner walls of the first through-hole and the second through-hole, and high-pressure gas is introduced into the interior of the air-floating slider 40 through the air compressor, and the high-pressure gas passes through the air passage. The circumferential surfaces of the first through-hole and the second through-hole are evenly spread.

Guide rod 61, the guide rod 61 is connected to the lower end of the air flotation slider 40, the lower end of the guide rod 61 fixes the floating platform test member 70, and the air flotation slider 40 moves along the first The optical axis 51 and the second optical axis 52 are free to attenuate movement in the vertical direction. The guide rod 61 and the fixed floating platform test member 70 follow the air-floating slider 40 along the first optical axis 51 and the second optical axis 52 . The two optical axes 52 are free to move attenuatingly in the vertical direction.

The guide portion 62 includes a guide hole. The guide portion 62 is disposed at the bottom of the board surface of the base plate 10 . The guide hole is formed by a portion of the board surface of the base plate 10 that extends forward. The guide rod 61 and The guide hole is matched and the hole diameter of the guide hole is larger than that of the guide rod 61 so that the inner wall of the guide hole is not touched during the free attenuated movement in the vertical direction. The guide portion 62 is disposed below the first lower fixing block 54 and the second lower fixing block 56 on the surface of the base plate 10 and is laterally located between the first lower fixing block 54 and the second lower fixing block. 56 in the middle.

In the present invention, the air-floating slider 40 moves vertically along the optical axis with extremely low surface roughness. There is a slight gap between the optical axis and the through-hole, and is arranged in a non-contact manner. However, this gap is very small and may not be in the air-floating position. When the level of the slider 40 is not accurate enough, the optical axis and the through-hole may come into contact with the wall surface. The present invention uses the air-floating slider 40 to provide air outlets at even intervals on the circumference of the inner wall of the through-hole, and compresses the air through the hole. High-pressure gas is introduced into the machine-to-air slider 40, and the high-pressure gas is evenly distributed circumferentially in the through-hole through the air channel, so that the optical axis can be corrected by the pressure of the high-pressure gas, so that the optical axis does not conflict with the wall of the through-hole. contact, reducing the impact of friction on free decay motion. However, the function of high-pressure gas correction has limitations. In order to form a relative motion closer to zero damping between the optical axis and the air-bearing slider 40, the horizontality of the air-bearing slider 40 needs to be within a reasonable range. Therefore, , the present invention can also adjust the levelness of the linear air flotation slider 40 by adjusting the screwing depth of the front and back teeth, so that the levelness of the air flotation slider 40 is within a reasonable range, so that the high-pressure gas correction function can be applicable, thereby With the combination of these two methods, a relative motion closer to zero damping is formed between the optical axis and the air bearing slider 40 . Therefore, the guide rod 61 is connected to the lower end of the air-floating slider 40, and the lower end of the guide rod 61 fixes the floating platform test member 70, and the air-floating slider 40 moves along the first light The shaft 51 and the second optical axis 52 move freely in the vertical direction, and the guide rod 61 and the fixed floating platform test member 70 follow the air-floating slider 40 along the first optical axis 51 and the second optical axis 52 . The optical axis 52 is free to attenuate movement in the vertical direction. In the relative motion closer to zero damping, the optical axis is limited so that the air-bearing slider 40 drives the fixed floating platform test component 70 only in the vertical direction along the optical axis. Motion, shielding the influence of other motion degrees of freedom in free attenuation. The combination of these methods synergistically improves the accuracy of drawing the vertical free attenuation curve drawn by collecting displacement data.

The displacement sensor collects displacement data of the movement of the air-floating slider 40 in real time. Displacement sensors, such as laser displacement sensors, are arranged to collect displacement movement data of the air-bearing slider 40 . The displacement sensor may be mounted on the fixed frame 80 .

The host computer receives the displacement data of the movement of the air-floating slider 40 collected by the displacement sensor, and draws the free attenuation curve of the fixed floating platform test component 70 based on the displacement data.

The air-floating slider 40 is rigidly connected to the guide rod 61 and the floating platform test component. Since the air-floating slider 40 can shield the movement in other directions through the restriction of the optical axis, the floating platform test component only has vertical movement. Therefore , the movement of the air-floating slider 40 of the present invention is consistent with the movement of the floating platform test component. Therefore, the movement monitoring of the air-floating slider 40 can reflect the movement of the floating platform test components,

The equilibrium position is to simulate the floating body structure (fixed floating platform test component 70) to decay freely in the water without other external friction. When simulating the balance of the floating body structure, the position of the electromagnet suction cup 22 can be expressed as on the base plate 10 The vertical equilibrium position, in an example, can be determined as, under the above premise, the vertical position of the base plate 10 where the upper end surface of the electromagnet chuck 22 is located is the equilibrium position.

The upper end surface of the electromagnet suction cup 22 and the upper end surface of the air flotation slider 40 are at the same height. Therefore, monitoring the vertical movement of the air flotation slider 40 can obtain the vertical movement data of the floating platform test component, and it can be understood that Under the above premise, the vertical position of the base plate 10 where the upper end surface of the air-floating slider 40 is located can also be used to represent the equilibrium position.

In addition, the lower end surface of the electromagnet 21 and the upper end surface of the electromagnet suction cup 22 are overlapping surfaces. It can also be understood that under the above premise, the vertical position of the base plate 10 where the lower end surface of the electromagnet 21 is located can also be used to represent the equilibrium position. The displacement data of the air-floating slider 40 compared to the equilibrium position collected by the displacement sensor can be processed as the vertical distance of the air-floating slider 40 from the equilibrium position, that is, the vertical distance of the simulated floating structure from the equilibrium position. .

Therefore, the free attenuation test method of the floating offshore platform of the present invention, using the test device to implement the test method, includes the following steps:

S10. Adjust the front and back thread screws to be screwed into one end of the base plate 10 to adjust the level of the base plate 10 so that the level of the air-floating slider 40 on the base plate 10 is within the required range.

S20. The air compressor performs and maintains high-pressure inflation of the first through hole and the second through hole of the air flotation slider 40, so that the first optical axis 51 and the first through hole matching the first optical axis 51 A first gap is provided and maintained between the holes, and a second gap is provided and maintained between the second optical axis 52 and the second through hole matching the second optical axis 52 .

S30. Adjust the screw of the adjusting device so that the vertical position of the electromagnet 21 connected to the screw is adjusted to a certain distance from the equilibrium position. Then, the electromagnet 21 is energized to allow the floating platform test component to pass through the air-floating slider 40 The electromagnet suction cup 22 is adsorbed and connected to the electromagnet 21, thereby causing the floating platform test component to deviate from the equilibrium position of the floating platform test component by a certain distance.

S40. When the flow field is stable, the electromagnet 21 is powered off, and the floating platform test component disconnects from the electromagnet 21 and moves freely. At this time, the structure falls vertically and begins to freely decay until it is completed. And the movement direction is restricted by the first optical axis 51 and the second optical axis 52, so that the floating platform test member only has vertical free attenuated movement, and the displacement of the air-floating slider 40 is collected in real time by the displacement sensor. data until the end of the free decay motion of the floating platform test member.

S50. Use the displacement data collected in real time by the displacement sensor to collect the movement of the air-floating slider 40, and draw a free attenuation curve from the displacement data. The free attenuation curve is the vertical movement of the fixed floating platform test member 70. A free decay curve in which free decay motion begins at a starting position that deviates from the equilibrium position.

S60. Repeat steps S10-S50 to draw multiple sets of free attenuation curves.

Embodiment 2: Different from the existing free attenuation physical model test methods of marine engineering structures, the present invention proposes a free attenuation physical model test method for floating offshore platforms with simple operation and high precision. The device in this method consists of an air bearing, a guide rod 61, an electromagnet 21 and a test component. Through the air-floating slider 40 and the optical axis, while constraining the floating offshore platform to move in other degrees of freedom, the friction force along the optical axis direction is smaller. The electromagnet 21 and the adjustment device can be used to accurately change the initial position of the free attenuation of the floating platform, avoiding the problem of low accuracy of manual pressing and affecting the flow field around the structure, thereby affecting the accuracy of the free attenuation. The invention can effectively ensure the test accuracy of the free attenuation physical model, is simple to operate, and has high test efficiency.

A free attenuation simulation method for floating offshore platforms based on linear air bearings. The device in this method mainly consists of: floating platform model specimen, fixed frame 80, air floating slider 40, optical axis, air compressor and electromagnetic Iron 21 regulation system. The free attenuation model test device is connected to the workbench through the fixed frame 80, thereby completing the fixation of the device. The air compressor is used to inflate the air floating slider 40, and the air enters the through hole of the air floating slider 40, so that the air floating slider 40 is not in contact with the optical axis. At the same time, the air-floating slider 40 can make the floating platform model move only along the optical axis direction, shielding the influence of other degrees of freedom of movement in free attenuation.

The electromagnet 21 adjustment system is mainly composed of the electromagnet 21, the electromagnet 21 adjustment rod and the electromagnet suction cup 22. Before starting the test, adjust the position of the electromagnet 21 by adjusting the length of the electromagnetic adjustment rod. Then, the electromagnet 21 and the electromagnet 21 are washed and adsorbed, and the floating structure deviates from the equilibrium position. Then the power is cut off, and the structure falls vertically and begins to decay freely until it is completed.

The optical axis is connected to the substrate 10 through a fixing device. The base plate 10 is connected to the fixed frame 80 through front and back thread bolts 32 . The levelness of the linear air-floating slider 40 can be adjusted by adjusting the screw-in depth of the front and back teeth. The floating platform test member is connected to the air flotation slider 40 through the guide rod 61 . The electromagnet 21 is connected to the electromagnet 21 adjusting rod through bolts 32, and then the electromagnet adjusting rod is connected to the base plate 10 through fasteners. The electromagnet sucker 22 is connected to the air-floating slider 40 through bolts 32 . Finally, the fixed frame 80 is connected to the workbench to realize the fixation of the entire device.

The invention can be applied to the free attenuation simulation of floating offshore platforms in different water depths, and has simple operation and high test accuracy. The electromagnet 21 system can deviate the floating body structure from the designated position, avoiding the problem of inaccurate initial deviation position caused by manual pressing. The solution of air-bearing slider 40, optical axis, and air compressor is used to restrict the movement in other directions while reducing the impact of friction on free attenuation. Testers do not need to enter the water to avoid errors in the free attenuation test structure caused by testers entering the water.

At the beginning of the test, the overall test device was fixed to the working platform, and the level of the free attenuation test device was adjusted by adjusting the screw-in depth of the positive and negative thread screws.

Subsequently, the air-floating slider 40 is inflated by an air compressor to ensure that the air-floating slider 40 is in non-contact with the optical axis.

When the test is officially started, the electromagnet 21 is first moved to a certain position through the electromagnet 21 adjusting rod. Then, the electromagnet 21 is energized, so that the floating platform test component is attracted to the electromagnet 21 through the electromagnet suction cup 22, thereby causing the floating platform test component to deviate from its equilibrium position by a specified distance.

When the flow field is stable, the electromagnet 21 is powered off, and the floating platform test component is disconnected from the electromagnet 21 and falls freely. When the free attenuation is completed, repeat this step to conduct multiple sets of free attenuation tests.

The invention can effectively ensure that the structure can move freely without friction in the direction of a single degree of freedom. The free attenuation test method is simple to operate and can greatly ensure the accuracy of the attenuated motion of the structure in the direction of a single degree of freedom. At the same time, it can reduce the error problem caused by test personnel entering the water, which is of great significance for the free attenuation test of floating platforms.

Experimental example:

Figure 2 shows the free attenuation curve obtained using the traditional manual pressing method. It can be clearly seen that although the curve is showing a free attenuation curve, due to the interference of other factors, the free attenuation curve appears irregular. It can be seen that the peak value of the free attenuation curve does not decrease slowly with the increase of time, and there is a problem that the rear peak value is higher than the front peak value. In the traditional model test, the structure is in the process of free attenuation. Except for the direction of the attenuation degree of freedom, other degrees of freedom are unconstrained. Therefore, under experimental conditions, the ideal single degree of freedom attenuation cannot be satisfied, and motion in other degrees of freedom is inevitable. When the tester stands in the water, there are disturbance forces in other directions except the free attenuation direction, which will increase the movement of the floating structure in other directions. In the single-degree-of-freedom free attenuation curve, it is very difficult to obtain an accurate free attenuation curve because of motion in other degrees of freedom directions.

Figure 3 is a free attenuation curve obtained by using the linear air bearing free attenuation physical model test method proposed by the present invention. It can be clearly seen that compared with Figure 2, its free attenuation curve has been greatly improved, and the peak value of the attenuation curve slowly decreases with time. The main reason is that by introducing the air-floating slider 40, the optical axis, and the air compressor, the air-floating slider 40 is rigidly connected to the floating body structure. At the same time, the air-floating slider 40 can only move with a single degree of freedom along the optical axis. It can effectively constrain the movement of other degrees of freedom. At the same time, because the linear air bearing is in contact with the optical axis with air, it can effectively reduce the friction between the linear air bearing and the optical axis, greatly avoiding the impact of friction on free attenuation. At the same time, an electromagnet 21 system is introduced to control the release of the structure through the electromagnet 21 to prevent test personnel from entering the water and further reduce the impact of test personnel's participation on free attenuation.

In the description of the present invention, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", " "Back", "Left", "Right", "Vertical", "Horizontal", "Top", "Bottom", "Inside", "Outside", "Clockwise", "Counterclockwise", "Axis", The orientations or positional relationships indicated by "radial direction", "circumferential direction", etc. are based on the orientations or positional relationships shown in the drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply the referred devices or components. Must have a specific orientation, be constructed and operate in a specific orientation and are therefore not to be construed as limitations of the invention.

In addition, the terms “first” and “second” are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of indicated technical features. Therefore, features defined as "first" and "second" may explicitly or implicitly include at least one of these features. In the description of the present invention, "plurality" means at least two, such as two, three, etc., unless otherwise expressly and specifically limited.

In the present invention, unless otherwise clearly stated and limited, the terms "installation", "connection", "connection", "fixing" and other terms should be understood in a broad sense. For example, it can be a fixed connection or a detachable connection. , or integrated; it can be mechanically connected, electrically connected or communicable with each other; it can be directly connected or indirectly connected through an intermediate medium; it can be the internal connection of two elements or the interaction between two elements, Unless otherwise expressly limited. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

In the present invention, unless otherwise expressly stated and limited, a first feature being "on" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. touch. Furthermore, the terms "above", "above" and "above" the first feature is above the second feature may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is higher in level than the second feature. "Below", "below" and "beneath" the first feature to the second feature may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature has a smaller horizontal height than the second feature.

In the present invention, the term "and/or" describes the association of associated objects, indicating that there can be three relationships, for example, A and/or B, which can mean: A exists alone, A and B exist simultaneously, and B exists alone. these three situations. The character "/" generally indicates that the related objects are in an "or" relationship. "At least one" refers to one or more; "At least one of A and B", similar to "A and/or B", describes the association relationship of associated objects, indicating that there can be three relationships, for example, A and B At least one of them can represent three situations: A alone exists, A and B exist simultaneously, and B exists alone.

As used herein, the terms "one embodiment," "some embodiments," "examples," "specific examples," or "some examples" mean specific features, structures, materials, or features described in connection with the embodiment or example. Features are included in at least one embodiment or example of the invention. In this specification, the schematic expressions of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the specific features, structures, materials or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, those skilled in the art may combine and combine different embodiments or examples and features of different embodiments or examples described in this specification unless they are inconsistent with each other.

The above are only preferred embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any person familiar with the technical field can, within the technical scope disclosed by the present invention, proceed according to the present invention. Any equivalent replacement or modification of the created technical solution and its inventive concept shall be covered by the protection scope of the invention.

Claims (10)

1. A floating offshore platform free attenuation test device, characterized by including: Base plate (10), the base plate (10) is arranged vertically; Electromagnet (21), the electromagnet (21) is arranged on the surface of the substrate (10); Adjustment device, the adjustment device includes a nut (31) and a bolt (32). The nut (31) is arranged on the upper part of one side of the base plate (10). The bolt (32) and the nut (31) cooperates. The electromagnet (21) is connected to the lower end of the bolt (32). The bolt (32) cooperates with the nut (31) to cause the bolt (32) to move vertically. The electromagnet (21) can move vertically to change the vertical initial position of the free attenuation test; Electromagnet suction cup (22), the electromagnet suction cup (22) is correspondingly arranged below the electromagnet (21). Before the start of the free attenuation test, the electromagnet suction cup (22) is in the vertical direction. The initial position is attracted to the electromagnet (21). At the beginning of the free attenuation test, the electromagnet suction cup (22) is disconnected from the electromagnet (21) in the vertical initial position; Air-floating slider (40), the electromagnet suction cup (22) is arranged on the air-floating slider (40), the air-floating slider (40) includes a third plate arranged transversely along the base plate (10). A through-hole and a second through-hole, the electromagnet chuck (22) is disposed on the upper surface of the air-floating slider (40) between the first through-hole and the second through-hole; Optical axis, the optical axis is axially arranged in the vertical direction and the optical axis is arranged on the base plate (10), and the optical axis cooperates with the air-bearing slider (40) to guide the The air-bearing slider (40) moves in the vertical direction, and the optical axis includes a first optical axis (51) and a second optical axis (52). The first optical axis (51) is connected with the air-bearing slider. The first through hole of the block (40) cooperates in the vertical direction, and the second optical axis (52) cooperates with the second through hole of the air bearing slide block (40) in the vertical direction. , there is a first gap between the first optical axis (51) and the first through hole matching the first optical axis (51), the first gap is the relationship between the peripheral surface of the first optical axis (51) and The inner wall of the first through hole is in the vertical gap, and high-pressure gas flows through the first through hole of the air bearing slider (40). The second optical axis (52) and the There is a second gap between the second through holes matched with the second optical axis (52). The second gap is the vertical distance between the peripheral surface of the second optical axis (52) and the inner wall of the second through hole. There is a gap in the direction, and high-pressure gas flows through the second through hole of the air-floating slider (40). The electromagnet chuck (22) is arranged between the first optical axis (51) and the third The upper surface of the air-floating slider (40) in the middle of the two optical axes (52) is disconnected by the electromagnet suction cup (22) and the electromagnet (21). The slider (40) moves freely in the vertical direction along the first optical axis (51) and the second optical axis (52), and the first optical axis (51) and the first optical axis (51) The first gap is maintained between the first through holes that cooperate with each other, and the second gap is maintained between the second optical axis (52) and the second through hole that cooperates with the second optical axis (52). ; Guide rod (61), the guide rod (61) is connected to the lower end of the air-floating slider (40), and the lower end of the guide rod (61) fixes the floating platform test member (70). By the The air-floating slider (40) moves freely in the vertical direction along the first optical axis (51) and the second optical axis (52), the guide rod (61) and the fixed floating platform test member (70 ) follows the air-bearing slider (40) to move freely in the vertical direction along the first optical axis (51) and the second optical axis (52); A displacement sensor that collects displacement data of the movement of the air-bearing slider (40) in real time; The upper computer receives the displacement data of the movement of the air-floating slider (40) collected by the displacement sensor, and draws the free attenuation curve of the fixed floating platform test component (70) based on the displacement data. 2. The floating offshore platform free attenuation test device according to claim 1, characterized in that air outlets are evenly spaced on the circumferential surfaces of the inner walls of the first through-hole and the second through-hole, and are supplied to the floating offshore platform through an air compressor. High-pressure gas is introduced into the air-floating slider (40), and the high-pressure gas is evenly distributed around the first through-hole and the second through-hole through the air channel. 3. The floating offshore platform free attenuation test device according to claim 1 or 2, characterized in that, it also includes Fixed frame (80). The fixed frame (80) is a frame with a rectangular structure. The first cross beam at the upper part of one side of the fixed frame (80) is connected to the base plate (10). The fixed frame (80) The second crossbeam on the lower part of one side that is opposite to the upper crossbeam is connected to the middle part of the two lower side crossbeams in the axial direction; The front and back thread bolts (32) include a first front and back thread bolt (91) and a second front and back thread bolt (92). One end of the first front and back thread bolt (91) is fixed on the first beam, and the other end of the first front and back thread bolt (91) is fixed on the first beam. One end is fixed on the upper end surface of the base plate (10), one end of the second front and back thread bolt (92) is fixed on the first cross beam, and the other end is fixed on the upper end surface of the base plate (10). A front and back thread bolt (91) and a second front and back thread bolt (92) are horizontally arranged at both ends of the upper end surface of the base plate (10). 4. The floating offshore platform free attenuation test device according to claim 3, characterized in that the optical axis is fixed on one side of the base plate (10) by the fixing block, and the fixing block It includes a first upper fixed block (53), a first lower fixed block (54), a second upper fixed block (55) and a second lower fixed block (56). The first upper fixed block (53), the first The lower fixing blocks (54) are arranged oppositely in the vertical direction and are fixed at two opposite positions in the vertical direction on one side of the base plate (10). The second upper fixing block (55) and the second lower fixing block (54) are The fixing blocks (56) are arranged oppositely in the vertical direction and are fixed at two opposite positions in the vertical direction on one side of the base plate (10). The first upper fixing block (53) and the second upper fixing block (56) are The block (55) arranges two relative positions of the lateral plate surface of the base plate (10) in a transverse direction, and the first lower fixing block (54) and the second lower fixing block (56) arrange the base plate (10) in a transverse direction. 10) Two relative positions of the transverse plate surface, the first optical axis (51) is fixed to the first upper fixed block (53) and the first lower fixed block (54) in the vertical direction in the axial direction ), the second optical axis (52) is fixed in the vertical direction between the second upper fixed block (55) and the second lower fixed block (56) in the axial direction. 5. The floating offshore platform free attenuation test device according to claim 4, characterized in that the first upper fixed block (53), the first lower fixed block (54) and the second upper fixed block (55) And the second lower fixed block (56) forms a connection hole from the forwardly extending portion of the plate surface of the base plate (10) to connect with the optical axis, so that there is a certain distance between the optical axis and the plate surface of the base plate (10). distance, the first upper fixed block (53) and the second upper fixed block (55) limit the maximum movement distance of the air-floating slider (40) in the vertical direction, and the first lower fixed block ( 54). The second lower fixed block (56) limits the minimum movement distance of the air-bearing slide block (40) in the vertical direction. 6. The floating offshore platform free attenuation test device according to claim 5, characterized in that it also includes a guide part (62), the guide part (62) includes a guide hole, and the guide part (62) is arranged on At the bottom of the board surface of the base plate (10), the guide hole is formed by the forward extending portion of the board surface of the base plate (10). The guide rod (61) cooperates with the guide hole. The guide hole The hole diameter is larger than the guide rod (61), so that the inner wall of the guide hole is not touched during the vertical free attenuation movement. 7. The floating offshore platform free attenuation test device according to claim 6, characterized in that the guide part (62) is arranged on the first lower fixed block (54) on the surface of the base plate (10). ) and below the second lower fixed block (56), and laterally in the middle of the first lower fixed block (54) and the second lower fixed block (56). 8. A free attenuation test method for floating offshore platforms, characterized in that the test method is implemented using the test device according to any one of claims 1 to 7, and the test method includes the following steps: S10. Adjust the screwing of the front and back thread bolts (32) on one end of the base plate (10) to adjust the level of the base plate (10) so that the levelness of the air-floating slider (40) on the base plate (10) is within the scope of need; S20. The air compressor performs and maintains high-pressure inflating of the first through hole and the second through hole of the air flotation slider (40), so that the first optical axis (51) and the first optical axis (51 ) There is and maintains a first gap between the first through-holes that cooperate with each other, and there is and maintains a second gap between the second optical axis (52) and the second through-hole that cooperates with the second optical axis (52); S30. Adjust the screw of the adjusting device so that the vertical position of the electromagnet (21) connected to the screw is adjusted to a certain distance from the equilibrium position, and then energize the electromagnet (21) to allow the floating platform test component to pass through the air. The electromagnet suction cup (22) of the floating slide block (40) is adsorbed and connected to the electromagnet (21), thereby causing the floating platform test component to deviate from the equilibrium position of the floating platform test component by a certain distance; S40. When the flow field is stable, the electromagnet (21) is powered off, and the floating platform test component disconnects from the electromagnet (21) and moves freely, and is connected by the first optical axis (51) and the second optical axis ( 52) Limit the direction of movement so that the floating platform test component only has vertical free attenuated motion, and the displacement sensor collects the displacement data of the movement of the air-floating slider (40) in real time until the floating platform test component The free decay movement ends; S50. Use the displacement data of the air-floating slider (40) movement collected in real time by the displacement sensor to draw a free attenuation curve. The free attenuation curve is when the fixed floating platform test component (70) deviates from the balance in the vertical direction. The starting position of the position begins the free decay curve of the free decay motion. 9. The free attenuation test method of the floating offshore platform according to claim 8, characterized in that it also includes S60. Repeat steps S10-S50 to draw multiple sets of free attenuation curves. 10. Application of the free attenuation test device of the floating offshore platform according to any one of claims 1 to 7 in the free attenuation test of the floating offshore platform.