NL2027503B1 - Natural exposure experiment device, system and method for components under variable amplitude loads - Google Patents

Natural exposure experiment device, system and method for components under variable amplitude loads Download PDF

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NL2027503B1
NL2027503B1 NL2027503A NL2027503A NL2027503B1 NL 2027503 B1 NL2027503 B1 NL 2027503B1 NL 2027503 A NL2027503 A NL 2027503A NL 2027503 A NL2027503 A NL 2027503A NL 2027503 B1 NL2027503 B1 NL 2027503B1
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load
variable amplitude
natural exposure
specimen
water tank
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NL2027503A
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Dutch (nl)
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Li Wen
Huang Peiyan
Zheng Xiaohong
Chen Zhanbiao
Lin Jiaxiang
Yang Yi
Guo Xinyan
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Univ South China Tech
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
    • G01N3/02—Details
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
    • G01N3/08—Investigating strength properties of solid materials by application of mechanical stress by applying steady tensile or compressive forces
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
    • G01N3/20—Investigating strength properties of solid materials by application of mechanical stress by applying steady bending forces
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
    • G01N2203/0001—Type of application of the stress
    • G01N2203/0005—Repeated or cyclic
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
    • G01N2203/003—Generation of the force
    • G01N2203/0032—Generation of the force using mechanical means
    • G01N2203/0033—Weight
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
    • G01N2203/02—Details not specific for a particular testing method
    • G01N2203/0202—Control of the test
    • G01N2203/0208—Specific programs of loading, e.g. incremental loading or pre-loading
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
    • G01N2203/02—Details not specific for a particular testing method
    • G01N2203/026—Specifications of the specimen
    • G01N2203/0262—Shape of the specimen
    • G01N2203/0264—Beam
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
    • G01N2203/02—Details not specific for a particular testing method
    • G01N2203/06—Indicating or recording means; Sensing means
    • G01N2203/067—Parameter measured for estimating the property
    • G01N2203/0676—Force, weight, load, energy, speed or acceleration

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  • Physics & Mathematics (AREA)
  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Biochemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Immunology (AREA)
  • Pathology (AREA)
  • Investigating Strength Of Materials By Application Of Mechanical Stress (AREA)

Abstract

The disclosure relates to a natural exposure experiment device, system and method for components under variable amplitude loads. The natural exposure experiment device for components under variable amplitude loads comprises a plurality of strip-shaped specimens, two ground beams provided in parallel, a loading water tank and a control device, Wherein the plurality of the specimens are placed on the two ground beams, the distance between the two ground beams is adapted to the length of the specimens, a digital display strain gauge and a displacement meter are provided in the middle of the bottom of the specimens, the loading water tank is provided above the specimens, two parallel loading heads are provided between the loading water tank and the specimens, a liquid level sensor is provided at the bottom of the inner side of the loading water tank, the water tank is provided with an inlet pipe and an outlet pipe, and the natural exposure experiment device further comprises a water storage device, a controller, a water supply pump, a drainage pump, a main inlet pipe and a main outlet pipe. The natural exposure experiment device for components under variable amplitude loads provided by the disclosure can realize the natural exposure experiment of the components under the coupling/co-action of various environments and variable amplitude load, and has good versatility and wide application range

Description

NATURAL EXPOSURE EXPERIMENT DEVICE, SYSTEM AND METHOD FOR COMPONENTS UNDER VARIABLE AMPLITUDE LOADS
TECHNICAL FIELD The disclosure relates to the experiment field of materials and structural mechanics, in particular to a natural exposure experiment device, system and method for components under variable amplitude loads.
IO BACKGROUND Major devices or major engineering structures in the fields of aerospace, land transportation, civil engineering, ships, ocean engineering, water conservancy and hydropower, ports, wind power generation, engineering machinery, etc. often bear external loads which are variable amplitude loads or even random loads that vary with time and space. For the anti-fatigue/durability design and safety evaluation of these major devices and major engineering structures, the experiment data currently used mostly come from indoor accelerated constant amplitude fatigue experiments of materials (small specimens) and a very small number of accelerated variable amplitude load experiments. These experiment conditions (environment and load) are obviously quite different from the actual service conditions of the above major devices and major engineering structures. The device and structure design and safety evaluation is based on the data obtained from the indoor accelerated experiment, which will result in security risks or adopt extremely conservative design methods to increase costs and waste resources.
In order to obtain the anti-fatigue/durability performance of the above major devices and major engineering structures more economically and accurately under the actual service environment and load, the ideal method is to develop a small number of natural exposure experiments of major devices and major engineering structure models or important components under variable amplitude loads, which are combined with a large number of accelerated experiments under the coupling/co-action simulating its service environment and loads. However, carrying out natural exposure experiments of structures or components under variable amplitude loads faces the following main difficulties: 1) it is difficult to set, apply and precisely control variable amplitude loads in long-term exposure experiments. For the long-term, continuous, and precise application and control of variable amplitude loads in natural exposure experiments, there is currently no good method; 2) the natural exposure experiment devices and methods of structures or components under variable amplitude loads have not been reported, but the natural exposure experiment methods and devices can be applied to structures or components under variable amplitude loads of multiple environments and multiple specimens haven’t been reported; 3) it is difficult to continuously and accurately test and collect experiment data under the coupling/co-action of natural exposure environments and variable amplitude loads for a long term. The static deformation of materials or small specimens reported in natural exposure experiments is tested by strain gauges, etc. However, it is difficult for the test method using strain gauges to continuously test and collect experiment data for a long term due to its short service life, environmental impact, and difficulty in safeguarding measures such as electricity; 4) it is difficult to operate experiment sites, experiment conditions and devices for a long term. The cycle of natural exposure experiments generally takes decades or even hundreds of years. In such a long cycle, it is extremely difficult to maintain the set experiment conditions (environment, stress, etc.) and ensure the function and stability of the experiment devices, and maintain the experiment sites; 5) in the natural exposure environment, the stress and deformation test methods of structures or components (specimens) under variable amplitude loads need to be improved. On the one hand, the current test method cannot adapt to the test of the deformation and stress changing law of the specimen caused by the change of the environment, it cannot capture the data of change of the deformation and stress of the specimen caused by the change of the environment completely and precisely in real time, and it is difficult to accurately measure the deformation of the specimen at the moment of sudden load change. On the other hand, the previous natural exposure experiment devices cannot simultaneously perform natural exposure experiments on multiple or a batch of the specimens under the co-action of the same environment and load, which is not conducive to statistical analysis of their long-term mechanical properties.
SUMMARY In view of the technical problems in the prior art, one of the objects of the disclosure is to provide a natural exposure experiment device for components under variable amplitude loads, which is capable of accurately controlling the load in long-term experiments and is suitable for experiments under multiple environments, facilitates long-term continuous test of experiment data, facilitates collection of data, and facilitates maintaining. In view of the technical problems in the prior art, the second object of the disclosure is to provide a natural exposure experiment system for components under variable amplitude loads, which is capable of further accurately controlling the load and is capable of testing multiple specimens at the same time, is suitable for experiments under multiple environments, facilitates long-term continuous test of experiment data, facilitates collection of data, and facilitates maintaining.
In view of the technical problems in the prior art, the third object of the disclosure is to provide a natural exposure test method for components under variable amplitude loads, which is capable of accurately simulating, applying and controlling variable amplitude loads in long-term experiments, is capable of capturing the data of change of the deformation and stress of the specimen caused by the change of the environment and load completely and precisely in real time, and is capable of simultaneously performing natural exposure experiments on multiple specimens under the coupling/co-action of the same environment and different environments and variable amplitude loads.
In order to achieve the above objects, the disclosure adopts the following technical solutions: A natural exposure experiment device for components under variable amplitude loads, comprising a plurality of strip-shaped specimens, two ground beams provided in parallel, a loading water tank and a control device, wherein the plurality of the specimens are placed on the two ground beams, the distance between the two ground beams is adapted to the length of the specimens, a digital display strain gauge and a displacement meter are provided in the middle of the bottom of the specimens, the loading water tank is provided above the specimens, two parallel loading heads are provided between the loading water tank and the specimens, a liquid level sensor is provided at the bottom of the inner side of the loading water tank, the water tank is provided with an inlet pipe and an outlet pipe, an inlet solenoid valve is provided on the inlet pipe, and an outlet solenoid valve is provided on the outlet pipe.
Further, the loading head is a cylindrical loading head, and the loading head is in line contact with the specimen.
Further, the side of the ground beam facing the specimen is a cylindrical surface.
Further, a pool is provided under the specimen, the pool is connected to a water pump, the pool is filled with salt water with the same salt content as sea water, and a rain-blocking device capable of blocking rainwater is provided above the loading water tank, the specimen and the pool.
Further, the loading head is a solid round steel column, and the loading head is welded to the bottom surface of the loading water tank.
A natural exposure experiment system for components under variable amplitude loads is provided, comprising a plurality of natural exposure experiment devices for components under variable amplitude loads according to any one of claims 1 to 5, and further comprising a water storage device, a controller, a water supply pump, a drainage pump, a main inlet pipe and a main outlet pipe, wherein the inlet pipe of each loading water tank is connected to the main inlet pipe, the outlet pipe of each loading water tank is connected to the main outlet pipe, the main inlet pipe and the main outlet pipe are both connected to the water storage device, the water supply pump is provided on the main inlet pipe, the drainage pump is provided on the main outlet pipe, and the water supply pump, the drainage pump, the inlet solenoid valve and the outlet solenoid valve are electrically connected with the control device.
Further, a plurality of natural exposure experiment devices for components under variable amplitude loads are arranged in a rectangular array.
A natural exposure experiment method for components under variable amplitude loads is provided, wherein the multi-step variable amplitude load spectrum is firstly set, and the method of measuring the deformation and stress of the specimen in stages 1s used: in the initial stage of the natural exposure experiment, according to the duration of each load step, using the method of ensuring that each load step is tested once in the action time and is continuously measured for two months; after two months, according to the changing law of temperature and humidity, using the method of measuring once at the time point of the lowest temperature and the highest temperature every day respectively, so as to measure the deformation and stress of the specimen; during the measurement, recording the physical parameters such as stress, strain, displacement, temperature, humidity and salinity.
Further, the variable amplitude load is set based on the load borne by the actual equipment or structure, the load data is collected manually or automatically by a detection system, and the principle of damage equivalence is applied. Multiple small loads are equivalent to a large load equal to the amount of damage to the device or structure to form an equivalent sequence consisted of large loads. Then the autocorrelation number or power spectral density of the equivalent load sequence is calculated by the probability analysis method, its probability distribution is checked to obtain the probability distribution function and the autocorrelation function or the power spectral density function of the equivalent load sequence. The functions are then input into commercial software with the random process simulation function or the self-compiled program for numerical simulation. A typical load spectrum that is capable of reflecting the characteristics of the actual load with the same probability distribution and autocorrelation number or power spectral density is obtained. Then according to the minimum sample volume of the load data, the deformation of the specimen and the frequency of stress test, the load simulation spectrum is divided into intervals according to the planned number of steps 5 of the variable amplitude loads, and the average of each interval is taken as the load amplitude. Multi-step variable amplitude load spectrum is generated. Finally, the equivalent (such as equivalent bending moment) method of the actual structure and the load borne by the specimen is then used to determine the size and frequency of various stages of load borne by the specimen.
Further, the method for applying, monitoring and controlling load is to compile the load to be applied to the specimen, that is, the variable amplitude load spectrum, into the control software, the controller sends a numerical signal to instruct the water supply pump, the drainage pump, the inlet solenoid valve, and the outlet solenoid valve to work to achieve loading, the load is monitored by the liquid level sensor and the control signal is sent to the controller, and then the controller sends an instruction so that the water supply pump, the drainage pump, the inlet solenoid valve, and the outlet solenoid valve work.
In general, the disclosure has the following advantages: 1) The natural exposure experiment device and system for components under variable amplitude loads provided by the disclosure can realize the natural exposure experiment of the components under the coupling/co-action of various environments and variable amplitude loads, and has good versatility and wide application range.
2) The natural exposure experiment device and system for components under variable amplitude loads provided by the disclosure can simultaneously perform natural exposure experiments on multiple specimens under the coupling/co-action of the same environment and load, and can also simultaneously perform natural exposure experiments on different specimens under the coupling/co-action of the same environment and different load spectra so as to analyze the long-term mechanical properties of the specimens under the interaction of the same or different load spectra with the natural exposure environment.
3) The natural exposure experiment device and system for components under variable amplitude loads provided by the disclosure has a simple and reasonable configuration and layout. The main components and members have excellent rigidity, strength, stability, reliability and durability. The device and system have the characteristics of being convenient in installation and maintenance, low in cost, etc.
4) The natural exposure experiment device and system for components under variable amplitude loads provided by the disclosure can solve the problems that it is difficult to precisely control variable amplitude loads in long-term experiments, and it is difficult to maintain experiment conditions, devices and sites for a long term.
5) The method for setting multi-step variable amplitude loads provided by the disclosure is determined after reasonable simplification based on the load spectrum borne by the device, structure or component in the actual service process. It has the characteristics that the probability statistical characteristics of the load are the same, and it is easy to simulate and compile, and is convenient for continuous measurement, precise application and control during the long-term experiment. Moreover, the variable amplitude load of the disclosure can reflect the actual bearing conditions of major devices or major engineering structures in the fields of aerospace, land transportation, civil engineering, ships, ocean engineering, water conservancy and hydropower, ports, wind power generation, engineering machinery, etc.
6) The natural exposure experiment method for components under variable amplitude loads provided by the disclosure has the characteristics of flexible changes in response to the deformation and stress changing laws caused by the changes in the environment and the load borne by the specimen. The measurement method of combining a long term and a short term is not only conducive to complete, real-time, long-term, continuous, and high-precision capture of the data of change of the deformation and stress of the specimen caused by the change of the environment and load, but also avoids the processing workload of big data.
BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic structural diagram of an example of a subtropical land environment of a natural exposure experiment device for components under variable amplitude loads according to the disclosure; FIG. 2 is a schematic structural diagram of an example of a subtropical land environment of a natural exposure experiment device for components under variable amplitude loads according to the disclosure from another perspective; FIG. 3 is a schematic structural diagram of an example of a subtropical wave splash zone environment of a natural exposure experiment device for components under variable amplitude loads according to the disclosure; FIG. 4 is a schematic structural diagram of an example of a subtropical wave splash zone environment of a natural exposure experiment device for components under variable amplitude loads according to the disclosure from another perspective; FIG. 5 is a structural schematic diagram of a natural exposure experiment system for components under variable amplitude loads according to the disclosure; FIG. 6 is a variable amplitude step load spectrum of a natural exposure experiment for components under variable amplitude loads according to an embodiment of the disclosure. In the figures, FIGS. 1 to 5 comprise: 1-loading water tank; 2-loading head; 3-specimen; 4-liquid level sensor; 51-inlet solenoid valve; 52-outlet solenoid valve; 61-water supply pump; 62-drainage pump; 7-inlet pipe; 8 -outlet pipe; 9-water tower, 10-digital display strain gauge; 11-displacement meter; 12-ground beam; 131-main inlet pipe; 132-main outlet pipe; l4-controller; 15-pool; 16-rain-blocking device; 17-cable.
DESCRIPTION OF THE EMBODIMENTS The disclosure will be described in further detail hereinafter. Embodiment 1 As shown in FIGS.1 to 2, the natural exposure experiment device, system and method for components under variable amplitude loads comprise: a subtropical environment setting, a natural exposure experiment device, a natural exposure experiment system, and a natural exposure experiment method. The subtropical environment is a subtropical land environment. The natural exposure experiment device for components under variable amplitude loads comprises a plurality of strip-shaped specimens, two ground beams provided in parallel, a loading water tank and a control device, wherein the plurality of the specimens are placed on the two ground beams, the distance between the two ground beams is adapted to the length of the specimens, a digital display strain gauge and a displacement meter are provided in the middle of the bottom of the specimens, the loading water tank is provided above the specimens, two parallel loading heads are provided between the loading water tank and the specimens, a liquid level sensor is provided at the bottom of the inner side of the loading water tank, the water tank is provided with an inlet pipe and an outlet pipe, an inlet solenoid valve is provided on the inlet pipe, and an outlet solenoid valve is provided on the outlet pipe. The loading head is a cylindrical loading head, and the loading head is in line contact with the specimen. The side of the ground beam facing the specimen is a cylindrical surface. The loading head is a solid round steel column, and the loading head is welded to the loading water tank.
A natural exposure experiment system for components under variable amplitude loads comprises a plurality of natural exposure experiment devices for components under variable amplitude loads, and further comprises a water storage device (a water tower), a controller, a water supply pump, a drainage pump, a main inlet pipe and a main outlet pipe, wherein the inlet pipe of each loading water tank is connected to the main inlet pipe, the outlet pipe of each loading water tank is connected to the main outlet pipe, the main inlet pipe and the main outlet pipe are both connected to the water storage device, the water supply pump is provided on the main inlet pipe, the drainage pump is provided on the main outlet pipe, and the water supply pump, the drainage pump, the inlet solenoid valve and the outlet solenoid valve are electrically connected with the control device.
A plurality of natural exposure experiment devices for components under variable amplitude loads are arranged in a rectangular array.
A natural exposure experiment method for components under variable amplitude loads is provided, and the method of measuring the deformation and stress of the specimen in stages is used: the multi-step variable amplitude load spectrum is firstly set, in the initial stage of the natural exposure experiment, according to the duration of each load step, using the method of ensuring that each load step is tested once in the action time and is continuously measured for two months; after two months, according to the changing law of temperature and humidity, using the method of measuring once at the time point of the lowest temperature and the highest temperature every day respectively, so as to measure the deformation and stress of the specimen; during the measurement, recording the physical parameters such as stress, strain, displacement, temperature, humidity and salinity.
The variable amplitude load is set based on the load borne by the actual equipment or structure, the load data is collected manually or automatically by a detection system, and the principle of damage equivalence is applied. Multiple small loads are equivalent to a large load equal to the amount of damage to the device or structure to form an equivalent sequence consisted of large loads. Then the autocorrelation number or power spectral density of the equivalent load sequence is calculated by the probability analysis method, its probability distribution is checked to obtain the probability distribution function and the autocorrelation function or the power spectral density function of the equivalent load sequence. The functions are then input into commercial software with the random process simulation function or the self-compiled program for numerical simulation. A typical load spectrum that is capable of reflecting the characteristics of the actual load with the same probability distribution and autocorrelation number or power spectral density is obtained. Then according to the minimum sample volume of the load data, the deformation of the specimen and the frequency of stress test, the load simulation spectrum is divided into intervals according to the planned number of steps of the variable amplitude loads, and the average of each interval is taken as the load amplitude. Multi-step variable amplitude load spectrum is generated as shown in FIG. 6. Finally, the equivalent (such as equivalent bending moment) method of the actual structure and the load borne by the specimen is then used to determine the size and frequency of various stages of load borne by the specimen. The method for applying, monitoring and controlling load is to compile the load to be applied to the specimen, that is, the variable amplitude load spectrum, into the control software. The controller sends a numerical signal to instruct the water supply pump, the drainage pump, the inlet solenoid valve, and the outlet solenoid valve to work to achieve loading. The load is monitored by the liquid level sensor and the control signal is sent to the controller, and then the controller sends an instruction so that the water supply pump, the drainage pump, the inlet solenoid valve, and the outlet solenoid valve work.
The natural exposure experiment device for components under variable amplitude loads comprises a loading head 2, a loading water tank 1, and a ground beam 12 for loading the specimen 3. Every two specimens 3 are placed in parallel on the ground beam 12, and the weight of the loading water tank 1 and the liquid contained therein is applied to the force of the specimen 3 the same as the gravity direction through the loading head 2. The liquid transmission and storage system is used to provide and adjust the amount of water to the loading water tank, comprising the inlet pipe 7, the outlet pipe 8, the inlet solenoid valve 51, the outlet solenoid valve 52, the water supply pump 61, the drainage pump 62, the water tower 9, the main inlet pipe 131 and the main outlet pipe 132 which are connected to the inlet pipe 7 and outlet pipe 8 of the loading water tank 1 and the water tower 9, respectively. The testing device comprises a liquid level sensor 4, a displacement meter 11 and a digital display strain gauge 10. The liquid level sensor 4 is located at the bottom of the inner side wall of the loading water tank 1 for measuring water pressure. The displacement meter 11 is located on the lower surface of the middle of the specimen 3 for testing the deflection (vertical displacement) of the specimen 3. The digital display strain gauge 10 is located on the lower surface (tensioned part) of the middle of the specimen 3 for measuring the stress and deformation of the tensioned part of the specimen 3. The control device comprises a controller 14, which is electrically connected to the inlet solenoid valve 51, the outlet solenoid valve 52, the water supply pump 61, and the drainage pump 62. The inlet pipe 7 and outlet pipe 8 of each loading water tank 1 are respectively provided with an inlet solenoid valve 51 and an outlet solenoid valve 52 to control the water entry and drainage of the loading water tank 1. The water pump comprises a water supply pump 61 and a drainage pump 62, which are connected to the main inlet pipe 131 and the main outlet pipe 132, respectively, for the water entry and drainage of each loading water tank 1. The controller 14 is located in the indoor monitoring room, and is connected to the inlet solenoid valve 51, the outlet solenoid valve 52, the water supply pump 61 and the drainage pump 62 through the cable 17 and the liquid level sensor 4 for controlling the water supply and drainage of each loading water tank 1 to ensure that the weight of each loading water tank 1 is consistent with the variable amplitude load spectrum.
As shown in FIG. 1, there are more than two ground beams 12, and the distance between every two ground beams 12 is adapted to the span of the specimen 3. The ground beam 12 is designed as a strip-shaped reinforced concrete (RC) member with a semicircular top, any length IS (set according to the size of the experiment site), a height of 20-30cm, and a width of 20-30cm, which is provided on a flat concrete floor, so that the specimen 3 can be placed stably. The ground beam 12 not only functions as a support, but also prevents the specimen 3 from being immersed by the accumulation of water, and facilitates the measurement of the stress and deformation of the specimen 3. A plurality of groups of the specimens 3 are placed in parallel above the ground beam 12 to form a plurality of loading devices. Each loading device is provided with two specimens 3, two loading heads 2 and a loading water tank 1. The distance between the two specimens 3 is adapted to the width of the bottom plate of the loading water tank 1 and the length of the loading head 2.
The loading head 2 is a solid round steel column. The axial direction of the loading head 2 is set in the width direction of the specimen 3 and the loading water tank 1. The length of the loading head 2 is the same as the width of the bottom plate of the loading water tank 1. The bottom of the loading head is in line contact with the upper surface of the specimen, and the upper part thereof 1s welded to the outer surface of the bottom plate of the loading water tank 1. Two parallel loading heads 2 are welded at the bottom of each loading water tank 1. The distance between the two loading heads 2 is equal to the point at the position of one third of the span of the specimen 3, forming a four-point bending loading form.
The loading water tank 1 shown in FIG. 1 is a rectangular container. A loading water tank 1 is placed on top of every two specimens 3. Its volume is set according to the experiment load.
The bottom plate and the side plates do not undergo significant deformation under full load, and no rollover occurs under strong wind. The top plate of the loading water tank 1 is provided as a cover that can be opened conveniently; and the bottom plate and the side plates are provided with reinforcing ribs, wherein the distance between the two reinforcing ribs in the middle of the bottom plate is the same as the distance between the two loading heads 2 bent at four points, and the reinforcing ribs are connected to the two loading heads 2 bent at four points; the side plate is provided with an inlet and an outlet, which are connected to the inlet pipe 7 and the outlet pipe 8, respectively.
The water tower 9 shown in FIG. 5 is a rectangular thick-walled container made of weathering structural steel, and its size is set according to the height of each loading water tank 1 (to ensure a certain water supply pressure), the total water volume to be adjusted in the experiment, and so on. The top is provided with an inlet and an outlet, which are connected with the main inlet pipe 131, the main outlet pipe 132, the water supply pump 61, and the drainage water pump 62. The bottom plate and the side plates are provided with reinforcing ribs. The water tower 9 is placed on a flat cement field, and no obvious deformation occurs during operation.
The main components of the controller 14 comprise: a central processing unit (CPU) for programming and communication with the touch screen and the output module, a digital output module for controlling the opening and closing of the inlet solenoid valve 51 and outlet solenoid valve 52, a PLC analog data collecting module for collecting sensor signals, an AC contactor for controlling the switches of the water supply pump 61 and the drainage pump 62, an air switch and other protective components.
The exposure test method of components in subtropical natural environment under variable amplitude loads comprises the steps of: 1) setting variable amplitude loads: the load data is collected manually or automatically by a detection system, the principle of damage equivalence is applied, a typical load spectrum of the bridge structure that is capable of being numerically simulated with the same statistical characteristics is obtained through the probability statistical analysis, and then is simplified to a multi-step variable amplitude load spectrum. The equivalent method of the actual structure and the load borne by the specimen 3 is then used to determine the size and frequency of various stages of load borne by the specimen 3.
2) designing and producing the specimen 3: according to the shape, size, stress situation of the actual load-bearing component and the experiment conditions of the natural exposure test field, the specimen 3 is designed according to a certain reduction ratio, and a batch of the specimens 3 are made according to relevant standards/regulations.
3) setting natural exposure environment: according to the actual subtropical service environment where the component is located, it is set as a subtropical land environment. For the subtropical land environment, it is only necessary to provide the reinforced concrete ground beam 12 for placing the specimen 3 on the subtropical outdoor open-air experiment site.
4) manufacturing a loading device: first, according to the type and size of a set of two specimens 3, the two loading heads 2 and one loading water tank 1 are made of stainless steel, according to the two loading positions of the four-point bending specimen 3, the two loading heads 2 are respectively welded to the loading position on the bottom surface of the loading water tank 1 in the form of line contact, the loading head 2 is fixedly connected to the loading water tank 1 to form a group of loading devices, an inlet and an outlet are provide on the side wall of the loading water tank 1, and the liquid level sensor 4 is installed below the outlet. Then, according to the number of groups of the specimens 3, the above process is repeated to make a IS plurality of groups of the same loading devices.
5) manufacturing a water tower 9: the size of the water tower 9 is set according to the number and height of the loading water tanks 1 and the total amount of water that needs to be adjusted in the experiment, and the water tower 9 is made of stainless steel plates according to the principle that the bottom plate and the side plates are not deformed when fully loaded, and the height of the water tower 9 is higher than the height of the loading water tank 1 after installation. Reinforcing ribs are provided on the bottom plate and the side plates, and an inlet and an outlet are provided on the top plate to be connected with the inlet pipe 7 and the outlet pipe 8.
6) installing specimen 3: a set group of two specimens 3 are first placed in parallel on the pre-set ground beam 12, the distance between the two specimens 3 is set according to the width of the loading water tank 1, so that the outer side of the specimen 3 is flush with the outer side of the loading water tank 1 or is a little closer to the inside, so that the specimen 3 can be exposed to the natural environment, and the loading head 2 and the loading water tank 1 can be stably placed on the group of two specimens 3. Then, the digital display strain gauge 10 is pasted and the displacement meter 11 is installed on the bottom of the middle span of the specimen 3. For other sets of the specimens, the above installation process is repeated.
7) installing storage water supply and transmission system: the water tower 9 is first installed and placed on a relatively high and flat concrete floor, the main inlet pipe 131 and the main outlet pipe 132 of the PVC thick wall of appropriate size are then selected according to the water supply, drainage, water supply time and drainage time requirements of the experiment system. The main inlet pipe 131 and the main outlet pipe 132 respectively connect the outlet and inlet of the water tower 9 with the inlet pipe 7 and the outlet pipe 8 of each loading water tank 1. 8) installing the control device: the CPU, the touch screen, the output module, the collecting module, the AC contactor, etc. are installed and integrated in the control room to form a controller 14, which is connected to the air switch, the pressure transmitter, the water supply pump 61, the drainage pump 62, the inlet solenoid valve 51, the outlet solenoid valve 52, and the liquid level sensor 4 through the cable 17. The control, data collection and post-processing software are then input into the CPU in the controller 14, and finally the variable amplitude load spectrum is input into the control program.
9) measuring and controlling load: the load applied to the specimen 3 is measured by the liquid level sensor 4, and the size of the load is controlled by the water level (water pressure) of the loading water tank 1. When the load of a certain step is adjusted to the target load, the liquid level sensor 4 sends a signal to the controller 14, and then the control system sends instructions to the water supply pump 61, the drainage pump 62, the inlet solenoid valve 51, and the outlet solenoid valve 52, so that the water supply pump 61 and the drainage pump 62 stop operating, and the inlet solenoid valve 51 and the outlet solenoid valve 52 are closed. The target load is the load data collected manually or automatically by a detection system based on the stress of the components in the actual structure, and the principle of damage equivalence is applied. Multiple small loads are equivalent to a large load equal to the amount of damage to the device or structure to form an equivalent sequence consisted of large loads. Then the autocorrelation number or power spectral density of the equivalent load sequence is calculated by the probability analysis method, its probability distribution is checked to obtain the probability distribution function and the autocorrelation function or the power spectral density function of the equivalent load sequence. The functions are then input into commercial software with the random process simulation function or the self-compiled program for numerical simulation. A typical load spectrum that is capable of reflecting the characteristics of the actual load with the same probability distribution and autocorrelation number or power spectral density is obtained.
Then according to the minimum sample volume of the load data, the deformation of the specimen 3 and the frequency of stress test, the load simulation spectrum is divided into intervals according to the planned number of steps of the variable amplitude loads, and the average of each interval is taken as the load amplitude. Multi-step variable amplitude load spectrum is generated. Finally, the equivalent (such as equivalent bending moment) method of the actual structure and the load borne by the specimen 3 is then used to determine the size and frequency of various stages of load borne by the specimen 3. The load spectrum of the actual component 1s converted to the load spectrum of the specimen 3, and the load spectrum of the specimen 3 is compiled into a variable amplitude load spectrum (target load spectrum) for natural exposure experiments.
10) long-term testing: the specimen 3 will deform under the coupling/co-action of natural exposure environment and variable amplitude load, and the deformation of the specimen 3 will in turn cause changes in its stress. Therefore, in order to ascertain the changing law of the long-term mechanical properties of the specimen 3 under the coupling/co-action of the natural exposure environment and the variable amplitude load, the accuracy of the test is guaranteed and the influence of non-environmental and non-external stress is minimized. For the concrete specimen 3, on the one hand, the disclosure places the cured reinforced concrete (RC) specimen 3 indoors for one year before implementing the natural exposure experiment, so as to minimize the influence of the shrinkage and creep of the concrete on its long-term mechanical properties. On the other hand, regardless of the material of the specimen 3, the disclosure uses the method of measuring the deformation and stress of the specimen 3 in stages according to the number of steps of the load spectrum: in the initial stage of the natural exposure experiment, according to the duration of each load step, using the method of ensuring that each load step is tested once in the action time and is continuously measured for two months; after two months, according to the changing law of temperature and humidity, using the method of measuring once at the time point of the lowest temperature and the highest temperature every day respectively, so as to measure the deformation and stress of the specimen 3. During the measurement, the physical parameters are recorded, such as stress, strain, displacement, temperature, humidity and salinity.
The deflection of the specimen 3 is measured by the displacement meter 11 located at the bottom of the middle span of the specimen 3, the strain is tested by the digital display strain gauge 10 pasted to the tensioned part of the specimen 3, the stress of the specimen 3 is measured by the liquid level sensor 4. The temperature, humidity and salinity are measured by a temperature hygrometer and a salinity meter respectively.
The above natural exposure experiment methods and devices can be used for natural exposure experiment of reinforced concrete (RC) structural parts and steel structural parts of buildings/structures such as bridges, tunnels, ports, wharves, roads, dams, venues, houses, ships, deep-sea platforms, automobiles, aircrafts, etc., reinforced RC structural parts of composite materials and fiber reinforced composite materials (FRP), FRP reinforced steel structural parts, steel-concrete composite structural parts, and sustained load components made of other materials.
In general, the disclosure has the following advantages.
The natural exposure experiment device and system for components under variable amplitude loads of the disclosure have the following advantages.
1) The natural exposure experiment device and system for components under variable amplitude loads provided by the disclosure can realize the natural exposure experiment of the components under the coupling/co-action of various environments and variable amplitude loads, and has good versatility and wide application range.
2) The natural exposure experiment device and system for components under variable amplitude loads provided by the disclosure can simultaneously perform natural exposure experiments on multiple specimens 3 under the coupling/co-action of the same environment and load, and can also simultaneously perform natural exposure experiments on different specimens 3 under the coupling/co-action of the same environment and different load spectra so as to analyze the long-term mechanical properties of the specimens under the interaction of the same or different load spectra with the natural exposure environment.
3) The natural exposure experiment device and system for components under variable amplitude loads provided by the disclosure has a simple and reasonable configuration and layout. The main components and members have excellent rigidity, strength, stability, reliability and durability. The device and system have the characteristics of being convenient in installation and maintenance, low in cost, etc.
4) The natural exposure experiment device and system for components under variable amplitude loads provided by the disclosure can solve the problems that it is difficult to precisely control variable amplitude loads in long-term experiments, and it is difficult to maintain experiment conditions, devices and sites for a long term.
The natural exposure experiment method for components under variable amplitude loads of the disclosure has the following advantages.
1) The method for setting multi-step variable amplitude loads in the experiment method of the disclosure is determined after reasonable simplification based on the load spectrum borne by the device, structure or component in the actual service process. It has the characteristics that the probability statistical characteristics of the load are the same, and it is easy to simulate and compile, and is convenient for continuous measurement, precise application and control during the long-term experiment. Moreover, the variable amplitude load of the disclosure can reflect the actual bearing conditions of major devices or major engineering structures in the fields of aerospace, land transportation, civil engineering, ships, ocean engineering, water conservancy and hydropower, ports, wind power generation, engineering machinery, etc.
2) The natural exposure experiment method for components under variable amplitude loads provided by the disclosure has the characteristics of flexible changes in response to the deformation and stress changing laws caused by the changes in the environment and the load borne by the specimen 3. The measurement method of combining a long term and a short term is not only conducive to complete, real-time, long-term, continuous, and high-precision capture of the data of change of the deformation and stress of the specimen 3 caused by the change of the environment and load, but also avoids the processing workload of big data.
Embodiment 2 The main device and method of this embodiment are the same as in embodiment 1, and the main differences are as follows.
As shown in FIGS. 3 and 4, the natural exposure environment described in this embodiment 1s a subtropical wave splash zone environment. There is also a pool 15 under the specimen 3, and the pool 15 is connected to a water pump. The pool 15 is filled with salt water with the same salt content as seawater. Rain-blocking devices 16 that can block rainwater are provided above the loading water tank 1, the specimen 3 and the pool 15. The pool 15 is a rectangular RC structure with any length (set according to the size of the experiment site), the width which 1s equal to the distance between the two ground beams 12, and the depth which is 1500-2000mm. Its surface needs to be subjected to anti-seepage water treatment, and its two long sides are constructed in accordance with the requirements of the above ground beam 12 and are equipped with drainage devices such as water pumps. The pool 15 is used to configure artificial seawater according to the change of seawater salinity in the subtropical coastal area, and a loading device is placed above the pool 15. The discharge of artificial seawater is completed by supporting water pumps. The rain-blocking device 16 (the rain shed) is an overhead inclined roof-like structure made of weather-resistant and light-permeable PVC and other materials. A stainless steel frame is erected above the pool 15 to prevent rainwater from flowing into the pool 15 and reducing salinity of artificial sea water.
Specifically, this embodiment adopts the exposure experiment method and device for components in subtropical natural environment under variable amplitude loads, and uses carbon fiber reinforced composite material (CFRP) to strengthen the reinforced concrete (RC) beam as the specimen 3. As a typical natural environment in the subtropical zone, the “subtropical wave splash zone environment” carries out natural exposure experiments for components under variable amplitude loads according to the following steps.
(1) Design and production of the specimen 3: according to relevant regulations, the common strengthening member "CFRP-reinforced RC simply supported beam" of the RC bridge in the subtropical zone designs the specimen 3 according to a certain reduction ratio. The size of the RC beam is 1850mm long 100mm widex200mm high, and the span is 1600mm; the concrete is C30; the main reinforcement is ®10II-grade steel bar, the erecting bars and stirrups are both ®81-grade steel bar, and the reinforcement ratio is 0.981%; CFRP is CFRP prepreg with 1560mm lengthx100mm widthx0.23mm calculated thickness woven with T700-12k carbon fiber yarn, such as a carbon fiber laminate (CFL); ultra-high-strength epoxy resin A, B glue is used to symmetrically paste the CFL to the bottom of the RC beam.
Regarding the production of the specimen 3, a steel cage is first rolled, strain gauges are pasted on the lower edge of the main reinforcement, and then concrete is poured. After being placed for 1 day, it is demoulded and maintained for 28 days. After that, it is placed indoors for 1 year, and then the carbon fiber laminate is pasted.
(2) Design and checking calculation of the main device 1) Design of the loading water tank 1: in order to facilitate statistical analysis of the long-term mechanical properties of the specimen 3, each loading water tank 1 (containing liquid) is determined as the load of two specimens 3; according to the size of the specimen and the dead load of the actual component, the load form of the specimen 3 in the natural exposure experiment is determined as four-point bending, and then after the stress and deformation of the loading water tank 1 are calculated according to the equivalent principle of bending moments, the size of the loading water tank 1 is set as: 2000mm lengthx800mm widthx1200mm height; finally, the material, shape and size of the components of the loading water tank 1 are determined as: Frame: in order to ensure the strength and rigidity of the loading water tank 1, square steel pipes are used to form a frame structure. The dimensions of the frame are: length 1=2000mm, width w=800mm, and height h=1200mm. The material of the square steel pipe is the 201 stainless steel, the cross-sectional dimension is 30::30mm, and the thickness is 2mm.
Bottom plate: it is made of the 201 stainless steel plate of 2mm thickness with reinforcing ribs. The size 1s 2000mm long x 800mm wide. Two reinforcing ribs are provided symmetrically in the length direction with a distance of 11=533 3mm in the middle of the bottom surface, and one reinforcing rib is provided at the middle position in the width direction. The material and cross-sectional dimension of the square steel pipe are the same as those of the above square steel pipe to increase the rigidity and load bearing of the bottom plate.
Side plate: it is made of the 201 stainless steel plate of 2mm thickness with reinforcing ribs.
The size of the two side plates in the length direction of the loading water tank 1 is 2000mm long * 1200mm high, and two reinforcing ribs in the height direction are provided, the size of the two side plates in the width direction of the loading water tank 1 is 800mm wide x 1200mm high, and a reinforcing rib in the width direction is provided. The reinforcing rib is made of the above square steel pipe of stainless steel, and its material and cross-sectional dimension are the same as the above square steel pipe.
Cover plate: it is made of the 201 stainless steel plate of 2mm thickness with reinforcing ribs. The size is 2000mm long x 800mm wide. One reinforcing rib is provided in the length direction of the loading water tank 1, and two reinforcing ribs are provided at equal intervals in the width direction. The material and size of the reinforcing ribs are the same as the above square steel pipe of stainless steel.
2) Design of water tower 9: the water tower 9 is used to supply and store water to the entire experiment system, and to form a certain water pressure for each loading water tank 1. For this embodiment, there are 15 loading water tanks 1 in total. According to the variable amplitude (step) load spectrum and considering the dead load of the bridge structure, the maximum water volume that needs to be adjusted for the entire system is 11.52m*. For this reason, the size of the water tower 9 is designed as: 3660mm lengthx 1500mm width*2150mm height, and the material, shape and size of its component parts are determined as: Frame: in order to ensure the strength and rigidity of the water tower 9, square steel pipes are used to form a frame structure. The dimensions of the frame are: length 1=3660mm, width w=1500mm, and height h=2150mm. The material of the square steel pipe is the 201 stainless steel, the cross-sectional dimension is 30x30mm, and the thickness is 2mm.
Bottom plate: it is made of the 201 stainless steel plate of 2mm thickness with reinforcing ribs. The size is 3660mm long x 1500mm wide. Three reinforcing ribs are provided at equal intervals in the length direction on the bottom surface, and two reinforcing ribs are provided at equal intervals in the width direction. The material and cross-sectional dimension of the steel pipe are the same as those of the above square steel pipe to increase the rigidity of the bottom plate.
Side plate: it is made of the 201 stainless steel plate of 2mm thickness with reinforcing ribs.
The size of the two side plates in the length direction of the water tower 9 is 3660mm long *2150mm high. Two reinforcing ribs are provided at equal intervals in the height direction, and three reinforcing ribs are provided at equal intervals in the length direction; the size of the two side plates in the width direction of the water tower 9 are 1500mm widex2150mm high, a reinforcing rib is provided in the width direction, and two reinforcing ribs are provided at equal intervals in the height direction. All reinforcing ribs are made of the above square steel tube of stainless steel, and its material and cross-sectional dimension are the same as the above square steel tube. Cover plate: it is made of the 201 stainless steel plate of 2mm thickness with reinforcing ribs. The size is 3660mm long x 1500mm wide. Two reinforcing ribs are provided at equal intervals in the length direction of the water tower 9 and one reinforcing rib is provided in the width direction. The material and size of the reinforcing ribs are the same as the above square steel pipe of stainless steel. The cover plate is provided with an inlet and an outlet, which are connected with the main inlet pipe 131 and the main outlet pipe 132. 3) Checking calculation Strength checking calculation: the maximum stresses of the bottom plate and the side plate of the loading water tank 1 and the water tower 9 under the set load are all less than the yield strength of the 201 stainless steel (275MPa), which meets the design requirements. Stiffness/deformation checking calculation: the maximum deformation of the bottom plate and the side plate of the loading water tank 1 and the water tower 9 under the set load (the volume of each loading water tank 1 is 1.92m® and the volume of the water tower 9 is about
11.8m*/maximum load) is less than Imm, which meets the design requirements. Stability checking calculation: since the loading water tank 1 is erected on two specimens 3, it is necessary to check whether it will overturn under the action of strong wind (typhoon of level 12). The checking calculation results show that when the volume of the loading water tank 1 is more than 60%, it will not overturn under the action of strong wind, and the stability is good. 4) Design and checking calculation of other main components/members. Loading head 2: the material is SUS304, the size is: the diameter ®1=30mm, and the length L=800mm. Ground beam 12: The material is reinforced concrete, and the concrete number is C30. The top radius of the ground beam 12 is R=300mm, the height is 300mm, and the width 1s 300mm. There are two lengths (10m and Sm). Among them, the one placed on the side of the pool 15 is
5m, and the rest is 10m.
Pool 15: the main structure is reinforced concrete, the concrete number is C30, and it is subjected to anti-seepage and anti-corrosion treatment. The size of the pool 15 is 5000mm longx1300mm widex1500mm deep, and artificial seawater with a depth of 1200mm and a salinity of 3% is maintained during the experiment.
Rain-blocking device 16 (rain shed): the size of the rain shed 16 is: length * width = height=5200x2400x1600mm, in which the support material is SUS304, which is square steel with the cross-section size of 50x50mm and the wall thickness of 3mm; the top material is transparent PVC with a thickness of Smm.
Checking calculation results: the strength of each component/member is sufficient, and its deformation is within the elastic range, which meets the design requirements.
(3) Building a natural exposure experiment field: a 18000mm long x 12000mm wide flat ground is circled on the campus of South China University of Technology in Guangzhou, and the experiment field is built according to the following steps.
1) The concrete is poured after leveling with the thickness of 200mm; 2) The ground beams 12 with a length of 10000mm and a length of 5000mm are respectively poured in the length direction at intervals of 1600mm; 3) A pool 15 is built between two 5000mm long ground beams 12; 4) A rain-blocking device 16 (rain shed) is built above the pool 15; 5) A fence is built around the experiment site.
(4) The subtropical wave splash zone natural environment exposure experiment for components under variable amplitude loads is carried out according to the following steps.
1) variable amplitude loads are set: the load data is collected manually or automatically by a detection system, the principle of damage equivalence is applied, a typical load spectrum of the RC bridge structure that is capable of being numerically simulated with the same statistical characteristics is obtained through the statistical analysis, and then is simplified to a multi-step variable amplitude load spectrum. The equivalent method of the actual structure and the load borne by the specimen 3 is then used to determine the size and frequency of various stages of load borne by the specimen 3. In this embodiment, the dead load of the RC bridge component accounts for 60% of the total load, and the vehicle load accounts for 40%. The maximum value of the total load is controlled to be lower than the cracking load of the concrete. The variable amplitude (vehicle) load spectrum is a step load spectrum. As shown in FIG. 6, 7 days form a cycle, each cycle has 28 steps, and the action time of each step is determined according to the proportion of the action frequency of each load amplitude value in the original load spectrum.
2) the loading water tank 1, the loading head 2, the water tower 9, the specimen 3, the controller 14, and other devices are manufactured; the water pump, the solenoid valve, the pipe, the liquid level sensor 4, the digital display strain gauge 10, the displacement meter 11, etc. are purchased, 3) the loading device is built according to the structure shown in FIG. 1. First, the two loading heads 2 are welded to the bottom plate of the loading water tank 1 according to the four-point bending loading position, and then the two specimens 3 are placed on the ground beam 12 beside the pool 15 and are located directly above the pool 15. A loading water tank 1 with a loading head 2 is placed on the two specimens 3 so that the loading head 2 and the upper surface of the specimen 3 form a line contact to form a set of loading devices. Afterwards, other sets of loading devices are built according to the above method; 4) the rain-blocking device 16 (rain shed) is built above the pool 15 and the loading device, as shown in FIG. 3. The number of rain-blocking devices 16 (rain sheds) is the same as that of the pool 15, and matches the number of loading devices; 5) the storage water supply and transmission system, the test device, and the control device are installed as shown in FIG. 5. In the storage water supply and transmission system, the pipes are weather-resistant round pipes of the PVC thick wall, which are divided into two types: one type comprises the main inlet pipe 131 and the main outlet pipe 132, and the size is ®64mm; the other type comprises the inlet pipe 7 connected to the loading water tank 1 and the outlet pipe 8, and the size is ®32mm; the water pump is a pipe centrifugal pump, which comprises a water supply pump 61 and a drainage pump 62; the solenoid valve of the control device is a normally closed two-port two-position direct-acting solenoid valve, which is provided on the inlet pipe 7 and the outlet pipe 8 of each loading water tank 1; the liquid level sensor 4 of the test device is a general-purpose pressure sensor, and is placed on the lower part of the inner side wall of the loading water tank 1, its measurement accuracy is 0.1%, and the system can control the deviation of the liquid level of less than Imm.
6) Artificial seawater with a salinity of 3% or 2% or 1% is manufactured, and is injected into the pool 15, and then the experiment system is started to start the natural exposure experiment.
(5) Long-term stress and deformation test of the specimen 3: the method of measuring the deformation and stress of the specimen 3 in stages is used according to the number of steps of the load spectrum: in the initial stage of the natural exposure experiment, according to the duration of each load step (see FIG. 6), using the method of ensuring that each load step is tested once in the action time and is continuously measured for two months; after two months, according to the changing law of temperature and humidity, using the method of measuring once at the time point of the lowest temperature and the highest temperature every day respectively, so as to measure the deformation and stress of the specimen.
During the measurement, the physical parameters are recorded, such as stress, strain, displacement, temperature, humidity and salinity.
The deflection of the specimen 3 is measured by the displacement meter 11 located at the bottom of the middle span of the specimen 3; the strain is tested by the digital display strain gauge 10 pasted to the tensioned part of the specimen 3 (an externally attached single-string intelligent strain gauge, with measuring accuracy 2e); and the stress of the specimen 3 is measured by the liquid level sensor 4. The temperature, humidity and salinity are measured by a temperature hygrometer and a salinity meter respectively. (6) Seawater concentration control: the artificial seawater in the pool 15 is set as: 2%, 1%, 2%, 3% according to the changes in salinity (measured data) of the sea area near several main estuaries of the Pearl River (Humen, Yamen, Modaomen) in four seasons, and is controlled according to the method of adjusting once a week, that is, the salt water in the pool 15 is replenished once a week, and its salinity is measured.
When the salinity deviates from the set value, it is adjusted by adjusting the salt or water volume until it reaches the set value.
The above embodiments are preferred embodiments of the disclosure, but the embodiments of the disclosure are not limited by the above embodiments, and any other changes, modifications, substitutions, combinations, simplification, etc. made without departing from the spirit and principle of the disclosure should be equivalent replacement methods, and are all included in the protection scope of the disclosure.

Claims (10)

ConclusiesConclusions 1. Een apparaat voor natuurlijke blootstellingsexperimenten voor componenten onder variabele amplitudebelastingen bestaande uit verschillende strookvormige specimens, twee parallelle grondbalken, een laadwatertank en een bedieningsapparaat, waarbij de verschillende specimens op de twee grondbalken worden geplaatst, de afstand tussen de twee grondbalken wordt aangepast aan de lengte van de specimens, een spanningsmeter met digitaal display en een verplaatsingsmeter worden voorzien in het midden van de onderkant van de specimens, twee parallelle laadkoppen worden voorzien tussen de laadwatertank en de specimens, een vloeistofniveausensor wordt aangebracht aan de onderkant van de binnenzijde van de laadwatertank, de watertank wordt voorzien van een inlaatpijp en een afvoerpijp, een elektromagnetische inlaatklep wordt voorzien op de inlaatpijp en een elektromagnetische afvoerklep wordt voorzien op de afvoerpijp.1. A device for natural exposure experiments for components under variable amplitude loads consisting of several strip-shaped specimens, two parallel ground beams, a loading water tank and a control device, placing the different specimens on the two ground beams, the distance between the two ground beams is adjusted according to the length of the specimens, a strain gauge with digital display and a displacement meter are provided in the center of the bottom of the specimens, two parallel charging heads are provided between the charge water tank and the specimens, a liquid level sensor is provided on the bottom of the inside of the charge water tank, the water tank is provided with an inlet pipe and a discharge pipe, an inlet electromagnetic valve is provided on the inlet pipe, and a discharge electromagnetic valve is provided on the discharge pipe. 2. Het apparaat voor natuurlijke blootstellingsexperimenten voor componenten onder variabele amplitudebelastingen volgens conclusie 1, waarbij de laadkop een cilindrische laadkop is en de laadkop in lijncontact met het specimen is. The apparatus for natural exposure experiments for components under variable amplitude loads according to claim 1, wherein the loading head is a cylindrical loading head and the loading head is in line contact with the specimen. 3. Het apparaat voor natuurlijke blootstellingsexperimenten voor componenten onder variabele amplitudebelastingen volgens conclusie 1, waarbij de zijkant van de grondbalk gericht naar het specimen een cilindrisch oppervlak is.The apparatus for natural exposure experiments for components under variable amplitude loads according to claim 1, wherein the side of the ground beam facing the specimen is a cylindrical surface. 4. Het apparaat voor natuurlijke blootstellingsexperimenten voor componenten onder variabele amplitudebelastingen volgens conclusie 1, waarbij: een bassin wordt voorzien onder het specimen, het bassin wordt aangesloten op een waterpomp, het bassin wordt gevuld met zout water met hetzelfde zoutgehalte als zeewater en boven de laadwatertank, het specimen en het bassin een apparaat is aangebracht dat het regenwater kan tegenhouden. The apparatus for natural exposure experiments for components under variable amplitude loads according to claim 1, wherein: a basin is provided below the specimen, the basin is connected to a water pump, the basin is filled with salt water having the same salinity as sea water and above the cargo water tank , the specimen and the basin is fitted with a device capable of retaining the rainwater. 5. Het apparaat voor natuurlijke blootstellingsexperimenten voor componenten onder variabele amplitudebelastingen volgens conclusie 1, waarbij de laadkop een massieve ronde stalen kolom is, en de laadkop aan de onderkant van de watertank is gelast.The natural exposure experiment apparatus for components under variable amplitude loads according to claim 1, wherein the loading head is a solid round steel column, and the loading head is welded to the bottom of the water tank. 6. Een systeem voor natuurlijke blootstellingsexperimenten voor componenten onder variabele amplitudebelastingen, bestaande uit verschillende apparaten voor natuurlijke blootstellingsexperimenten voor componenten onder variabele amplitudebelastingen volgens een van de conclusies 1 tot en met 5 en verder omvattende een wateropslagapparaat, een controller, een watertoevoerpomp, een drainagepomp, een hoofdinlaatpiijjp en een hoofdafvoerpijp, waarbij de inlaatpijp van elke laadwatertank is aangesloten op de hoofdinlaatpijp, de afvoerpijp van elke laadwatertank is aangesloten op de hoofdafvoerpijp, de hoofdinlaatpijp en de hoofdafvoerpijp beide zijn aangesloten op het wateropslagapparaat, de watertoevoerpomp is voorzien op de hoofdinlaatpijp, de drainagepomp is voorzien op de hoofdafvoerpijp en de watertoevoerpomp, de drainagepomp, de elektromagnetische inlaatklep en de elektromagnetische afvoerklep elektrisch zijn verbonden met het bedieningsapparaat.A system for natural exposure experiments for components under variable amplitude loads, comprising various devices for natural exposure experiments for components under variable amplitude loads according to any one of claims 1 to 5 and further comprising a water storage device, a controller, a water supply pump, a drainage pump, a main inlet pipe and a main discharge pipe, the inlet pipe of each cargo water tank is connected to the main inlet pipe, the discharge pipe of each cargo water tank is connected to the main discharge pipe, the main inlet pipe and the main discharge pipe are both connected to the water storage device, the water supply pump is provided on the main inlet pipe, the drainage pump is provided on the main drain pipe, and the water supply pump, drainage pump, inlet electromagnetic valve and drain solenoid valve are electrically connected to the control device. 7. Het systeem voor natuurlijke blootstellingsexperimenten voor componenten onder variabele amplitudebelastingen volgens conclusie 6, waarbij: verschillende apparaten voor natuurlijke blootstellingsexperimenten voor componenten onder variabele amplitudebelastingen worden opgesteld in een rechthoekige reeks.The natural exposure experiment system for components under variable amplitude loads according to claim 6, wherein: different natural exposure experiment devices for components under variable amplitude loads are arranged in a rectangular array. 8. Een methode voor natuurlijke blootstellingsexperimenten voor componenten onder variabele amplitudebelastingen, waarbij eerst het belastingsspectrum met variabele amplitude en meerdere stappen wordt ingesteld en de methode voor het meten van de vervorming en de druk van het specimen in fasen wordt gebruikt: in de beginfase van het natuurlijke blootstellingsexperiment, volgens de duur van elke belastingsstap, met behulp van de methode om ervoor te zorgen dat elke belastingsstap eenmaal in de actietijd wordt getest en gedurende twee maanden voortdurend wordt gemeten; na twee maanden, volgens de veranderende wet van temperatuur en vochtigheid, met behulp van de methode van eenmaal meten op het tijdstip van respectievelijk de laagste en de hoogte temperatuur elke dag, om de vervorming en druk van het specimen te meten; tijdens de meting het registreren van de fysieke parameters zoals druk, spanning, verplaatsing, temperatuur, vochtigheid en zoutgehalte.8. A method of natural exposure experiments for components under variable amplitude loads, which first sets the variable amplitude load spectrum and multisteps and uses the method of measuring the deformation and pressure of the specimen in stages: in the initial phase of the natural exposure experiment, according to the duration of each load step, using the method of ensuring that each load step is tested once in the action time and continuously measured for two months; after two months, according to the changing law of temperature and humidity, using the method of measuring once at the time of the lowest and highest temperature, respectively, each day, to measure the deformation and pressure of the specimen; during the measurement recording the physical parameters such as pressure, tension, displacement, temperature, humidity and salinity. 9. De methode voor natuurlijke blootstellingsexperimenten voor componenten onder variabele amplitudebelastingen volgens conclusie 8, waarbij: de variabele amplitudebelasting wordt ingesteld op basis van de belasting die wordt gedragen door de werkelijke apparatuur of constructie, de belastinggegevens handmatig of automatisch door een detectiesysteem worden verzameld, het beginsel van gelijkwaardigheid van schade wordt toegepast, een typisch belastingsspectrum dat de kenmerken van de werkelijke belasting kan weergeven en numeriek kan worden gesimuleerd, wordt verkregen door middel van statistische analyse en vervolgens wordt vereenvoudigd tot een belastingsspectrum met variabele amplitude en meerdere stappen en de equivalente methode van de werkelijke constructie en de door het specimen gedragen belasting daarna wordt gebruikt om de grootte en de frequentie van verschillende fasen van belasting gedragen door het specimen te bepalen. The natural exposure experiment method for components under variable amplitude loads according to claim 8, wherein: the variable amplitude load is set based on the load carried by the actual equipment or structure, the load data is collected manually or automatically by a detection system, the principle of damage equivalence is applied, a typical load spectrum that can represent the characteristics of the real load and simulate numerically is obtained through statistical analysis and then simplified to a variable amplitude multi-step load spectrum and the equivalent method of the actual structure and the load borne by the specimen thereafter is used to determine the magnitude and frequency of different phases of load borne by the specimen. 10. De methode voor natuurlijke blootstellingsexperimenten voor componenten onder variabele amplitudebelastingen volgens conclusie 9, waarbij de methode voor het aanbrengen, controleren en bedienen van de belasting bestaat uit het verzamelen van de belasting die op het specimen moet worden aangebracht, met name het belastingsspectrum met variabele amplitude, in de bedieningssoftware, de controller een numeriek signaal stuurt om de watertoevoerpomp, de drainagepomp, de elektromagnetische inlaatklep en de elektromagnetische afvoerklep te instrueren om te werken om de belasting te realiseren, de belasting wordt gecontroleerd door de vloeistofniveausensor en het controlesignaal naar de controller wordt gestuurd en de controller daarna een instructie stuurt zodat de watertoevoerpomp, de drainagepomp, de elektromagnetische inlaatklep en de elektromagnetische afvoerklep werken.The method for natural exposure experiments for components under variable amplitude loads according to claim 9, wherein the method of applying, controlling and operating the load consists of collecting the load to be applied to the specimen, in particular the variable load spectrum amplitude, in the control software, the controller sends a numerical signal to instruct the water supply pump, the drainage pump, the inlet electromagnetic valve and the drain electromagnetic valve to work to realize the load, the load is controlled by the liquid level sensor, and the control signal to the controller is sent and then the controller sends an instruction so that the water supply pump, the drainage pump, the inlet solenoid valve and the drain solenoid valve are working.
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