A large-span stability test device and method for LNG tank dome

Abstract

The present invention discloses a large-span stability test device and method for LNG storage tank domes, including an experimental model, a loading mechanism, a monitoring mechanism and a data acquisition mechanism; the experimental model is arched, and the main body of the experimental structure is a single-layer rib-ring type spherical lattice shell structure; the loading mechanism is used to load the loading points on the experimental model; a monitoring mechanism is provided at the loading point, and the monitoring mechanism is used to monitor the mechanical state, displacement state and strain state of the loading point; the monitoring mechanism is connected to the data acquisition mechanism by electrical signals. The stability changes of large-span domes under the action of internal and external loads (such as concrete pouring) in an experimental environment can be continuously and dynamically monitored to effectively test the overall bearing capacity and stability of the large-span dome, and help solve the technical difficulties in the design of ultra-large storage tank domes.

Description

Technical Field

[0001] The invention relates to the technical field of design of extra-large LNG storage tanks, and in particular to a large-span stability test device and method for a LNG storage tank dome. Background Art

[0002] LNG storage tanks are responsible for storing LNG, and their safe operation plays a vital role in the smooth operation of the entire LNG industry chain. In recent years, due to the continuous increase in demand for natural gas, natural gas has been greatly developed and utilized, and LNG storage tanks have also developed in the direction of large reserves. Compared with conventional storage tanks, the weight of the dome of super-large LNG storage tanks increases, the area increases by several thousand square meters, and there are many technical difficulties such as large span, long tank diameter and low horizontal stiffness, complex vibration mode of the tank structure, and difficult casting. It is urgent to independently master the design and construction technology of the dome of super-large LNG storage tanks, which has great strategic and economic significance for promoting the development of my country's national economy.

[0003] 22x10 4 m 3 LNG storage tanks are the largest LNG storage tanks under construction in China. Only a few design or research institutes in China have mastered the full set of design technologies, and there is currently a lack of experimental research on the stability of large-span domes of LNG storage tanks. In order to meet the data and theoretical support requirements for the design of storage tank domes in China, a large-span stability experimental device and method for LNG storage tank domes is provided, which is of great significance to revealing the changing laws and failure mechanisms of the stability of large-span domes under internal and external loads (such as concrete pouring). Summary of the invention

[0004] The purpose of the present invention is to provide a large-span stability test device and method for an LNG storage tank dome, so as to solve the problems existing in the above-mentioned prior art and effectively monitor the overall bearing capacity and stability of the large-span dome.

[0005] To achieve the above-mentioned purpose, the present invention provides the following scheme: The present invention provides a large-span stability experimental device for an LNG storage tank dome, comprising an experimental model, a loading mechanism, a monitoring mechanism and a data acquisition mechanism; the experimental model is arched, and the main body of the experimental structure is a single-layer rib-ring spherical lattice shell structure; the loading mechanism is used to load the loading point on the experimental model; the monitoring mechanism is arranged at the loading point, and is used to monitor the mechanical state, displacement state and strain state of the loading point; the monitoring mechanism is connected to the data acquisition mechanism by electrical signals.

[0006] Preferably, the experimental model comprises main radial ribs, secondary radial ribs, ring rods and reinforcing ribs, and the lattice shell of the experimental model of the single-layer rib-ring spherical lattice shell structure is a symmetrical structure, the main radial ribs and the secondary radial ribs are evenly distributed along the radial direction of the lattice shell and intersect at the top of the sphere; the ring rods and the reinforcing ribs are annularly distributed along the circumferential direction of the lattice shell, and the ring rods and the reinforcing ribs form a rigid intersecting system with the main radial ribs and the secondary radial ribs.

[0007] Preferably, the experimental model further comprises peripheral supports, which are composed of square steels welded to the outermost secondary radial ribs and square steels arranged circumferentially at the center of the outermost circle of secondary radial ribs, and the peripheral supports are used to apply effective full constraints to the frame model.

[0008] Preferably, the ring rod, main radial ribs, secondary radial ribs and reinforcing ribs are connected to form a plurality of unit grids from large to small from the arch to the lower part, and only two rods intersect at each node; the position of the loading point is the upper surface of the node of the rigid intersecting system formed by the intersection of the main radial rib or the secondary radial rib and the ring rod or the reinforcing rib.

[0009] Preferably, the loading mechanism includes a hydraulic loader, a hydraulic load-bearing frame, a piping system and a hydraulic operating table. The hydraulic loader is used to apply a load to the loading point, and the hydraulic load-bearing frame is used to withstand the balance force system generated when the hydraulic loader loads the experimental model; the piping system is used to connect the hydraulic loader and the hydraulic load-bearing frame with the hydraulic operating table to realize hydraulic loading; the hydraulic operating table is used to control the state of the on-site output equipment and perform automatic control loading.

[0010] Preferably, the monitoring mechanism includes a resistance strain gauge, a strain meter and a temperature compensation gauge, the resistance strain gauge is arranged at the loading point, and the resistance strain gauge is electrically signal connected to the strain gauge; the temperature compensation gauge is set based on the bridge characteristics using a compensation block compensation method, and the temperature compensation gauge is connected to the strain gauge and is used to eliminate the impact of temperature changes on the resistance strain gauge.

[0011] Preferably, the monitoring mechanism also includes a displacement sensor and a tension sensor, and the tension sensor is arranged below the loading point. At the same time, the displacement sensor is also fixed below the loading point, and a distance is left between the displacement sensor and the ground; the displacement sensor and the tension sensor are both electrically connected to the data acquisition mechanism.

[0012] Preferably, the data acquisition mechanism includes a data acquisition card and a data acquisition processing system, and the displacement sensor and the tension sensor are connected to the data acquisition card via electrical signals.

[0013] A method for testing the large-span stability of a LNG storage tank dome is applied to the above-mentioned large-span stability test device for a LNG storage tank dome, and comprises the following steps:

[0014] Step 1: Select the number and position of loading points according to the experimental requirements, and paste the resistance strain gauges at the loading points;

[0015] Step 2: Connect and weld the experimental devices and instruments correctly, and use a multimeter to test them in time to ensure that the experimental instruments and circuits are accurate and usable;

[0016] Step 3: Use the hydraulic loading mechanism to conduct a preload test, cycle twice, and then unload, check the reliability of the device and personnel, eliminate the gaps in the nodes and joints, and put the structure into normal working condition;

[0017] Step 4: Use a graded equal load method and a hydraulic loader to load, first apply the initial load, after the initial load is applied, adjust the instrument to zero and simultaneously record the data of the strain gauge, displacement sensor and tension sensor as the initial reading;

[0018] Step 5: Load in stages. After adding each level of load, the load needs to be stabilized for 5 minutes, and then the parameter data is read;

[0019] Step 6: To avoid accidental errors in the experiment, at least two loading cycles are required;

[0020] Step 7: Read the experimental data from the data acquisition agency and analyze and process the acquired data.

[0021] Compared with the prior art, the present invention has achieved the following beneficial technical effects:

[0022] 1. The large-span structural performance experimental device of the LNG storage tank dome provided by the present invention can continuously and dynamically monitor the structural performance changes of the large-span dome during the loading process under the experimental environment, effectively verify the dome design calculation results, ensure the structural strength of the dome design, improve the accuracy of the design, and support the dome cement pouring construction operation, thereby providing support for the actual construction and construction of the dome.

[0023] 2. The frame model provided by the present invention has a simple structure, strong practicability, high safety, and is easy to expand. It can provide an important reference for revealing the structural performance change law and failure mechanism of the large-span dome of the LNG storage tank during the loading process.

[0024] 3. The loading device provided by the present invention can realize flexible arrangement of loads in space and loading force, so as to effectively simulate the load conditions of the LNG storage tank dome under actual working conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0026] Figure 1 It is the top view of the experimental model;

[0027] Figure 2 This is the overall structural diagram of the large-span stability test device for the LNG tank dome;

[0028] Figure 3 This is a schematic diagram of the peripheral support structure of the experimental model;

[0029] Figure 4 is a working schematic diagram of the hydraulic loading mechanism (where point A is the loading point);

[0030] Figure 5 This is the overall schematic diagram of loading, monitoring and data collection during the experiment;

[0031] Among them, 11. main radial ribs, 12. secondary radial ribs, 13. ring rods, 14. reinforcing ribs, 15. peripheral supports; 16. square steel; 21. loading points, 22. resistance strain gauges, 23. strain gauges, 24. temperature compensation sheets, 25. data acquisition cards, 26. data acquisition and processing systems; 31. experimental models, 32. tension sensors, 33. displacement sensors, 34. hydraulic loaders, 35. hydraulic load frames, 36. piping systems, 37. hydraulic control panels. DETAILED DESCRIPTION

[0032] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] The purpose of the present invention is to provide a large-span stability test device and method for an LNG storage tank dome, so as to solve the problems existing in the above-mentioned prior art and effectively monitor the overall bearing capacity and stability of the large-span dome.

[0034] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0035] like Figure 1-5As shown, this embodiment provides a large-span stability test device for a tank dome, including an experimental model 31, a loading mechanism, a monitoring mechanism, and a data acquisition mechanism.

[0036] The main radial ribs 11 and the secondary radial ribs 12 in the present invention constitute the radial ribs of the experimental model 31, and the two are evenly distributed along the radial direction and intersect at the top of the ball; the ring rods 13 and the reinforcing ribs 14 are distributed in the circumferential direction, and form a rigid intersecting system with the main radial ribs 11 and the secondary radial ribs 12; the peripheral support 15 is composed of square steel 16 welded to the outermost secondary radial ribs and square steel 16 arranged in the center of the outermost circle of secondary radial ribs, so as to impose effective full constraints on the experimental model, and the square steel 16 here can also be replaced by H-shaped steel. Further, the attached Figure 1 The experimental model 31 is arched, and the main structure is a single-layer rib-ring spherical lattice shell, which adopts a symmetrical structure, and the curvature of the curve on any symmetric surface in the track is equal. In the experimental model, the ring rod 13, the main radial rib 11, the secondary radial rib 12, and the reinforcing rib 14 are connected to form multiple unit grids from large to small from the top of the arch to the bottom. Each node has only two rods intersecting, and the node structure is simple.

[0037] The loading point 21 of the present invention is arranged on the upper surface of the node of the rigid intersecting system formed by the intersection of the main radial rib 11 or the secondary radial rib 12 and the ring rod 13 or the reinforcing rib 14, and is loaded by a multi-channel servo hydraulic loading system to achieve comprehensive loading according to experimental needs.

[0038] The resistance strain gauge 22 of the present invention is mainly arranged on the upper surface of the outer ring radial rib of the node of the rigid intersecting system formed by the intersection of the main radial rib 11 or the secondary radial rib 12 of the experimental model and the ring rod 13 or the reinforcing rib 14. When the model undergoes mechanical deformation due to loading, the resistance wire of the resistance strain gauge 22 is also deformed, thereby changing the resistance of the resistance wire, and the change value is proportional to the strain on the surface of the component to which the strain gauge is pasted.

[0039] The strain gauge 23 of the present invention is connected to the resistance strain gauge 22, and converts the resistance signal of the resistance strain gauge 22 when the change occurs into a voltage signal, and then displays the corresponding strain value through operations such as amplification, filtering, and analog-to-digital conversion. The temperature compensation sheet 24 adopts the compensation block compensation method based on the bridge characteristic setting, and connects the resistance strain gauge 22 and the strain gauge 23. The resistance strain gauge 22 pasted on the model for measuring the model strain is used as a working sheet and connected to the ab bridge arm of the bridge; in addition, the resistance strain gauge 22 of the same specification is pasted on a piece of material that is the same material as the experimental model 31 but does not participate in the deformation, and is ensured to be under the same temperature conditions, and connected to the bridge and the working sheet to form a half bridge of the measuring bridge. The other two bridge arms of the bridge are fixed non-inductive standard resistors inside the strain gauge 23, forming an equal-arm bridge to eliminate the influence of temperature changes on the resistance strain gauge 22 and reflect the actual strain of the model.

[0040] The data acquisition card 25 of the present invention is connected to the tension sensor 32 and the displacement sensor 33 to collect sensor data, and is connected to the data acquisition processing system 26 to realize data acquisition and processing. The data acquisition processing system 26 mainly monitors the operation process of the experimental device, obtains experimental data, analyzes and processes it, and assists the data acquisition card 25 to realize data acquisition during the experiment.

[0041] In this embodiment, the tension sensor 32 should cooperate with the hydraulic loader 34, be arranged near the loading point 21, and be connected to the data acquisition card 25. The tension sensor 32 uses two tension transmission parts to transmit force. When the loading force changes, the tension sensor 32 can convert the physical data signal into an electronic signal output that can be accurately measured. The displacement sensor 33 should be fixed at a certain height below the loading point and above the ground to monitor the deformation of the loading point.

[0042] The hydraulic loader 34 is a main component of the hydraulic loading mechanism. The hydraulic oil with a certain pressure is pressed into the working cylinder of the hydraulic loader 34 by a high-pressure oil pump, so that it pushes the piston, applies a load to the test model 31, and the applied load is measured by the tension sensor 32. The hydraulic load-bearing frame 35 is used to bear the balance force system generated when the hydraulic loader 34 loads the structure.

[0043] The pipeline system 36 is used to connect the hydraulic loader 34, the hydraulic bearing frame 35, and the hydraulic control panel 37 of the hydraulic loading mechanism to realize the hydraulic loading of the model. The hydraulic control panel 37 of the present invention is composed of various valves, hydraulic components and electrical control components, programmable controllers (PLCs) and other components, and is connected to various parts of the hydraulic loading mechanism including but not limited to the hydraulic loader 34 and the hydraulic bearing frame 35 through the pipeline system 36, monitors the input status of the site, and controls the status of the output device of the site according to the logic controller, thereby realizing automatic control loading.

[0044] The experimental method of the above-mentioned LNG tank dome large-span stability experimental device has the following specific steps:

[0045] Step 1: According to the experimental requirements, the number and position of the loading points 21 are selected, and the resistance strain gauge 22 is pasted on the upper surface of the outer diameter rib.

[0046] Step 2: Correctly connect and weld the experimental devices and instruments, and use multimeters and other instruments to conduct timely inspections to ensure that the experimental instruments and circuits are accurate and usable.

[0047] Step 3: Use the hydraulic loading mechanism to conduct a preload test and cycle twice, then unload, check the reliability of the device and personnel, eliminate the gaps in the nodes and joints, and put the structure into normal working condition.

[0048] Step 4: Use the hydraulic loader 34 to load with graded equal loads, first apply a small initial load, and after the initial load is applied, adjust the instrument to zero and simultaneously record the initial readings of the strain gauge 23, the displacement sensor 33, the tension sensor 32, etc.

[0049] Step 5: Load in stages. After adding each level of load, the load needs to be stabilized for 5 minutes, and then the parameter data is read.

[0050] Step 6: To avoid accidental errors in the experiment, at least two loading cycles are required.

[0051] Step 7: Read the experimental data from the data acquisition agency and analyze and process the acquired data.

[0052] It should be noted that it is obvious to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present invention, and any figure mark in the claims should not be regarded as limiting the claims involved.

[0053] The present invention uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only used to help understand the method and core ideas of the present invention. At the same time, for those skilled in the art, according to the ideas of the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A large-span stability test device for LNG tank dome, characterized by: The invention comprises an experimental model, a loading mechanism, a monitoring mechanism and a data acquisition mechanism; the experimental model is arched, and the main body of the experimental model is a single-layer rib-ring type spherical lattice shell structure; the loading mechanism is used to load the loading point on the experimental model; the monitoring mechanism is arranged at the loading point, and the monitoring mechanism is used to monitor the mechanical state, displacement state and strain state of the loading point; the monitoring mechanism is connected to the data acquisition mechanism by electrical signals; The experimental model comprises main radial ribs, secondary radial ribs, ring rods and reinforcing ribs. The lattice shell of the experimental model of the single-layer rib-ring spherical lattice shell structure is a symmetrical structure. The main radial ribs and the secondary radial ribs are evenly distributed along the radial direction of the lattice shell and intersect at the top of the sphere. The ring rods and the reinforcing ribs are annularly distributed along the circumferential direction of the lattice shell, and the ring rods and the reinforcing ribs form a rigid intersecting system with the main radial ribs and the secondary radial ribs. The experimental model further includes a peripheral support, which is composed of square steel welded to the outermost secondary radial ribs and square steel arranged circumferentially at the center of the outermost secondary radial ribs, and the peripheral support is used to apply effective full constraints to the frame model; The ring rod, main radial rib, secondary radial rib and reinforcing rib are connected to form a plurality of unit grids from large to small from the arch to the bottom, and only two rods intersect at each node; the position of the loading point is the upper surface of the node of the rigid intersecting system formed by the intersection of the main radial rib or the secondary radial rib and the ring rod or the reinforcing rib.

2. The LNG storage tank dome large span stability test device according to claim 1 is characterized in that: The loading mechanism includes a hydraulic loader, a hydraulic load-bearing frame, a pipeline system and a hydraulic operating table. The hydraulic loader is used to apply a load to the loading point, and the hydraulic load-bearing frame is used to withstand the balance force system generated when the hydraulic loader loads the experimental model; the pipeline system is used to connect the hydraulic loader and the hydraulic load-bearing frame with the hydraulic operating table to realize hydraulic loading; the hydraulic operating table is used to control the state of the on-site output equipment and automatically control the loading.

3. The LNG storage tank dome large span stability test device according to claim 1 is characterized in that: The monitoring mechanism includes a resistance strain gauge, a strain meter and a temperature compensation gauge. The resistance strain gauge is arranged at the loading point, and the resistance strain gauge is electrically connected to the strain gauge. The temperature compensation gauge is set based on the bridge characteristics using a compensation block compensation method, and the temperature compensation gauge is connected to the strain gauge and is used to eliminate the impact of temperature changes on the resistance strain gauge.

4. The LNG storage tank dome large span stability test device according to claim 3 is characterized in that: The monitoring mechanism also includes a displacement sensor and a tension sensor. The tension sensor is arranged below the loading point. At the same time, the displacement sensor is also fixed below the loading point, and a distance is left between the displacement sensor and the ground. The displacement sensor and the tension sensor are both electrically connected to the data acquisition mechanism.

5. The LNG storage tank dome large span stability test device according to claim 4 is characterized in that: The data acquisition mechanism includes a data acquisition card and a data acquisition processing system. The displacement sensor and the tension sensor are connected to the data acquisition card through electrical signals, and the data acquisition card is electrically connected to the data acquisition processing system.

6. A method for testing the large-span stability of a LNG storage tank dome, applied to the large-span stability testing device for a LNG storage tank dome according to any one of claims 1 to 5, characterized in that: The following steps are involved: Step 1: Select the number and position of loading points according to the experimental requirements, and paste the resistance strain gauges at the loading points; Step 2: Connect and weld the experimental devices and instruments correctly, and use a multimeter to test them in time to ensure that the experimental instruments and circuits are accurate and usable; Step 3: Use the loading mechanism to conduct a preload test, cycle twice, and then unload to check the reliability of the device, eliminate the gaps between nodes and joints, and put the structure into normal working state; Step 4: Use a graded equal load method and a hydraulic loader to load, first apply the initial load, after the initial load is applied, adjust the instrument to zero and simultaneously record the data of the strain gauge, displacement sensor and tension sensor as the initial reading; Step 5: Load in stages. After adding each level of load, the load needs to be stabilized for 5 minutes, and then the parameter data is read; Step 6: To avoid accidental errors in the experiment, at least two loading cycles are required; Step 7: Read the experimental data from the data acquisition agency and analyze and process the acquired data.

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