A multi-factor coupling FRP reinforced concrete beam environment simulation test device

Abstract

The application discloses a kind of environmental simulation test device of FRP reinforced concrete beam considering multi-factor coupling, belong to civil engineering structure durability test equipment technical field, the device includes integrated environmental box system, multi-mode loading system, multi-field coupling measurement and control system and auxiliary support system;Integrated environmental box system includes double-layer insulation stainless steel structure, and multi-mode loading system is integrated with environmental box;Multi-field coupling measurement and control system is with PLC as core, realizes multi-parameter centralized control, data acquisition and multiple safety protection.The application adopts the above-mentioned environmental simulation test device of FRP reinforced concrete beam considering multi-factor coupling, realizes the independent regulation and control of mechanical load, temperature and humidity field, corrosion medium, freeze-thaw cycle multiple factors and collaborative coupling, meets the durability test demand of FRP reinforced concrete in complex environment such as cold region, coastal area, industrial corrosion, improves test authenticity, stability and automation level.

Description

Technical Field

[0001] This invention relates to the field of civil engineering structural durability testing equipment technology, and in particular to an environmental simulation test device for FRP-reinforced concrete beams that considers multiple factors coupled together. Background Technology

[0002] Due to its advantages such as lightweight, high strength, corrosion resistance, and excellent fatigue resistance, FRP (fiber-reinforced polymer) reinforcement is increasingly widely used in concrete structures such as cross-sea bridges, port terminals, industrial plants, and buildings in cold regions. During actual service, FRP-reinforced concrete beams are subjected to long-term static or fatigue loads, while simultaneously exposed to complex environments including temperature variations, humidity fluctuations, salt spray, acid and alkaline gases, seawater corrosion, and freeze-thaw cycles. Their mechanical property degradation and durability failure are the result of the coupled effects of multiple factors, including mechanical loads, temperature and humidity, corrosive media, and freeze-thaw cycles. Experimental conditions based on a single factor or a small number of superimposed factors cannot accurately reflect the structural service degradation patterns, leading to significant discrepancies between experimental results and actual engineering conditions, making it difficult to accurately guide structural design and life assessment.

[0003] The existing experimental equipment has the following obvious defects: The environmental simulation function is limited. Most devices can only achieve a simple superposition of one or two factors such as mechanics and temperature and humidity, or mechanics and corrosion. They lack the ability to simulate freeze-thaw cycles and multiple types of corrosive media in a coordinated manner, and cannot cover complex service scenarios such as cold regions, coastal areas, and industrial corrosion. The separate design of the loading system and the environmental chamber requires the specimen to be disassembled and transported multiple times, which can easily cause interruption of the loading state, secondary damage to the specimen, and poor long-term test stability. Multi-parameter collaborative control has low precision. Parameters such as temperature, humidity, load, corrosion concentration, and freeze-thaw cycle are difficult to independently control and synchronously couple, which cannot meet the requirements of automated and highly stable operation for long-term durability testing. Summary of the Invention

[0004] The purpose of this invention is to provide an environmental simulation test device for FRP-reinforced concrete beams that considers multiple factors coupled together, so as to achieve independent control and synergistic coupling of multiple factors such as mechanical load (static / fatigue), temperature and humidity field, corrosive medium (salt spray / gas), and freeze-thaw cycle, to meet the durability test requirements of FRP-reinforced concrete in complex environments such as cold regions, coastal areas, and industrial corrosion, and to improve the authenticity, stability and automation level of the test.

[0005] To achieve the above objectives, the present invention provides an environmental simulation test device for FRP-reinforced concrete beams considering multi-factor coupling, including an integrated environmental chamber system, a multi-mode loading system, a multi-field coupling measurement and control system, and an auxiliary support system; The integrated environmental chamber system includes a main environmental chamber body, inside which a freeze-thaw cycle module and a corrosive medium module are fixedly installed; The multi-mode loading system includes a portal steel structure reaction frame, a hydraulic servo actuator, and a force transmission assembly. The portal steel structure reaction frame spans above the integrated environmental chamber system. The hydraulic servo actuator is fixed in the middle of the portal steel structure reaction frame and extends downward into the main body of the environmental chamber. The force transmission assembly is located at the lower end of the hydraulic servo actuator and corresponds to and cooperates with the specimen. It is used to apply static loads or fatigue loads to the specimen. The multi-field coupling measurement and control system includes an electrical control cabinet, which contains a PLC controller. The PLC controller is connected to a touch screen and a host computer. The auxiliary support system includes an exhaust purification unit, a media circulation unit, and a maintenance and repair unit to ensure long-term stable operation of the device; the exhaust purification unit is connected to the interior of the main body of the environmental chamber.

[0006] Preferably, the main body of the environmental chamber is a double-layer insulated stainless steel chamber, the top of the main body of the environmental chamber is equipped with a sealed top cover, the side wall of the main body of the environmental chamber is equipped with an observation window and a specimen loading and unloading door, and the bottom of the chamber is equipped with a medium collection tank and a drain valve.

[0007] Preferably, the freeze-thaw cycle module includes an immersion evaporator, an electric heating element, a refrigerant circulation unit, and a freeze-thaw controller. The immersion evaporator and the electric heating element are both installed inside the main body of the environmental chamber. The refrigerant circulation unit is connected to the immersion evaporator. The freeze-thaw controller is connected to the immersion evaporator and the electric heating element respectively to achieve temperature range control of -40℃ to 60℃ and custom freeze-thaw cycle setting.

[0008] Preferably, the corrosive medium module includes a salt spray generating unit, a medium immersion unit, and a gas corrosion unit; the output end of the salt spray generating unit extends into the main body of the environmental chamber, the medium immersion unit is located at the bottom of the main body of the environmental chamber, and the gas corrosion unit is connected to the interior of the main body of the environmental chamber through a gas distributor, achieving a salt spray deposition rate of 1.0~2.0 mL / 80 cm. 2 •h adjustment and CO2 and SO2 gas concentration control from 0 to 5% vol.

[0009] Preferably, the hydraulic servo actuator has a rated load of ≥500kN, an output load frequency of 0.1~10Hz, and a load control accuracy of ±0.1%FS.

[0010] Preferably, the force transmission assembly includes a force sensor, a displacement gauge, a distribution beam, a ball joint support, and an adjustable support arranged sequentially from top to bottom. An FRP-reinforced concrete beam specimen is placed between the distribution beam and the ball joint support. The adjustable support is fixed to the bottom of the main body of the environmental chamber to accommodate specimens of different sizes. The distribution beam and the ball joint support work together to ensure load centering and uniform transmission.

[0011] Preferably, the multi-field coupling measurement and control system is equipped with overload protection, over-temperature protection, medium leakage protection and power failure protection modules, the data acquisition frequency is adjustable from 1Hz to 100Hz, and the data is automatically stored in Excel or CSV format.

[0012] Preferably, the PLC controller is connected to the freeze-thaw cycle module, the corrosive medium module, the temperature and humidity control module, and the hydraulic servo actuator signal respectively to realize centralized control of multiple parameters, data acquisition and storage.

[0013] Preferably, the media circulation unit includes a media storage tank, which is connected to the corrosive media module and the media collection tank via a circulation pump.

[0014] Therefore, the present invention employs the above-mentioned environmental simulation test device for FRP-reinforced concrete beams that considers multiple factors coupled, and the technical effects are as follows: 1) Achieving synergistic coupling of four factors—mechanics, temperature and humidity, corrosion, and freeze-thaw cycles—results in test results that are closer to actual engineering practices; 2) The loading system and environmental chamber are designed as an integrated unit to avoid specimen handling and ensure continuous stability of the load condition; 3) It is flexible in function and supports switching between multiple modes such as salt spray, immersion, and gas corrosion, and is suitable for FRP reinforced concrete beam specimens of different specifications and types.

[0015] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of an embodiment of the environmental simulation test device for FRP-reinforced concrete beams that considers multiple factors coupled according to the present invention.

[0017] Figure Labels 1. Integrated environmental chamber system; 101. Main chamber body; 102. Sealed top cover; 103. Observation window; 104. Specimen loading and unloading door; 105. Immersion evaporator; 106. Electric heating element; 107. Salt spray generator; 108. Gas distributor; 109. Temperature and humidity sensor; 110. FRP reinforced concrete beam specimen; 111. Medium collection tank; 112. Drain valve; 2. Multi-mode loading system; 201. Portal steel structure reaction frame; 202. Hydraulic servo actuator; 203. Force sensor; 204. Displacement needle; 205. Distribution beam; 206. Ball joint support; 207. Adjustable support; 3. Multi-field coupling measurement and control system; 301. Electrical control cabinet; 302. Touch screen; 303. Host computer; 4. Auxiliary support system; 401. Exhaust and purification unit; 402. Medium storage tank; 403. Circulation pump. Detailed Implementation

[0018] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0019] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "first," "second," and similar terms used in this invention do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0020] like Figure 1 As shown, the present invention provides an environmental simulation test device for FRP-reinforced concrete beams considering multi-factor coupling, including an integrated environmental chamber system 1, a multi-mode loading system 2, a multi-field coupling measurement and control system 3, and an auxiliary support system 4.

[0021] Example 1: Freeze-thaw-salt spray-static load coupled durability test (simulation of cold coastal environment) 1. Specimen installation and positioning Open the specimen loading / unloading door 104 and hoist the FRP-reinforced concrete beam specimen 110 into the main body 101 of the environmental chamber. Adjust the spacing of the adjustable supports 207 according to the specimen length to ensure the specimen is placed stably. Install the ball joint support 206 and the distribution beam 205 in sequence. At the same time, fix the displacement pin 204 inside the main body 101 of the environmental chamber and align it with the center of the specimen, ensuring that it is aligned with the hydraulic servo actuator 202. Close the specimen loading / unloading door 104 and the sealing top cover 102, confirm that the chamber is reliably sealed, and observe the specimen fixation status inside the main body 101 of the environmental chamber through the observation window 103 on the opposite side of the specimen loading / unloading door 104.

[0022] 2. Preset test parameters Test parameters were input via touchscreen 302: preloaded static load 50kN; long-term load during coupling phase 150kN; freeze-thaw cycle temperature range -20℃ to 20℃, single cycle 8h; salt spray deposition 1.5mL / 80cm. 2 •h; Data acquisition frequency 10Hz.

[0023] 3. Automatic operation of the test The test procedure is initiated. The hydraulic servo actuator 202 applies a static load according to the set parameters. The hydraulic servo actuator 202 is fixed to the middle of the portal steel reaction frame 201 and extends downwards into the main body 101 of the environmental chamber. The PLC controller in the electrical control cabinet 301 provides real-time feedback closed-loop control via the force sensor 203 to maintain load stability. The freeze-thaw cycle module, salt spray generator 107, and temperature and humidity control module are started simultaneously. The temperature and humidity control module includes a temperature and humidity sensor 109, fixed to the inner wall of the main body 101 of the environmental chamber. The immersion evaporator 105 and the electric heating element 106 work alternately to achieve freeze-thaw cycles, ensuring uniform diffusion of salt spray onto the specimen surface. The multi-field coupled measurement and control system collects data such as load, displacement, temperature, humidity, freeze-thaw cycles, and salt spray concentration in real time and automatically stores it in the host computer 303.

[0024] 4. End of Experiment and Post-processing After the test is completed, the system automatically unloads, starts the exhaust purification unit 401 to discharge the corrosive gas in the chamber; opens the drain valve 112 to empty the residual liquid in the medium collection tank 111; and exports all test data for evaluation of specimen deterioration patterns and durability.

[0025] Example 2: Temperature and Humidity-Gas Corrosion-Fatigue Load Coupled Test (Industrial Corrosion Environment Simulation) 1. Sealing and Environmental Pretreatment The FRP-reinforced concrete beam specimen 110 was installed, fixed, and sealed in the chamber. The gas corrosion unit was activated, and CO2 was introduced into the chamber through the gas distributor 108 to stabilize the concentration at 3% vol. The temperature and humidity control module raised the temperature inside the chamber to 60℃ and the relative humidity to 90%RH, and maintained the environment for 30 minutes.

[0026] 2. Application of fatigue load The fatigue load parameters are set via the host computer 303: frequency 2Hz, load amplitude 20kN~80kN; the hydraulic servo actuator 202 is started to output the fatigue load, and the force sensor 203 and displacement meter 204 monitor and provide feedback in real time.

[0027] 3. Data Acquisition and Security Protection The monitoring and control system continuously records parameters such as load, displacement, temperature, humidity, and CO2 concentration at a 10Hz acquisition frequency, and automatically saves them in CSV format. In the event of overload, over-temperature, or media leakage during operation, the system immediately triggers protection mechanisms and issues audible and visual alarms.

[0028] 4. Shutdown and Specimen Inspection After the test reaches the set number of cycles, the machine will automatically stop, shut down the gas and temperature and humidity system, and open the chamber after exhaust and purification. The specimens will be taken out for appearance, load-bearing capacity and deformation tests, and fatigue durability data comparison and analysis will be completed.

[0029] Example 3: Seawater Immersion-Freeze-Thaw-Static Load Coupling Test (Marine Freeze-Thaw Environment Simulation) 1. Medium preparation and specimen clamping Artificial seawater is injected into the medium storage tank 402 and transported to the medium immersion unit through the circulation pump 403, so that the bottom of the FRP reinforced concrete beam specimen 110 is immersed in seawater; the adjustable support 207 is adjusted and the FRP reinforced concrete beam specimen 110 is fixed, and the sealing top cover 102 is closed.

[0030] 2. Coupling parameter settings Set the static load to 100kN; freeze-thaw cycle -15℃ to 15℃, cycle 6h; maintain the immersion liquid level at 1 / 3 of the specimen height; control the temperature and humidity at RH above 95%.

[0031] 3. Coupled test run Loading and freeze-thaw cycles are synchronized, and the medium circulation unit automatically replenishes and filters the liquid. The measurement and control system collects load, displacement, temperature, liquid level, and number of freeze-thaw cycles throughout the process, ensuring long-term stable operation.

[0032] 4. End of the experiment Stop loading and freeze-thaw cycles, drain the soaking solution and clean the tank, and export the data for durability analysis of FRP concrete beams in marine freeze-thaw environments.

[0033] Therefore, the present invention adopts the above-mentioned environmental simulation test device for FRP-reinforced concrete beams that considers multiple factors coupling, so as to realize the independent control and synergistic coupling of multiple factors such as mechanical load (static / fatigue), temperature and humidity field, corrosive medium (salt spray / immersion / gas), and freeze-thaw cycle, to meet the durability test requirements of FRP-reinforced concrete in complex environments such as cold regions, coastal areas, and industrial corrosion, and improve the authenticity, stability and automation level of the test.

[0034] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. An environmental simulation test device for FRP-reinforced concrete beams considering multi-factor coupling, characterized in that: This includes an integrated environmental chamber system, a multi-mode loading system, a multi-field coupling measurement and control system, and an auxiliary support system; The integrated environmental chamber system includes a main environmental chamber body, inside which a freeze-thaw cycle module and a corrosive medium module are fixedly installed; The multi-mode loading system includes a portal steel structure reaction frame, a hydraulic servo actuator, and a force transmission component. The portal steel structure reaction frame spans above the integrated environmental chamber system. The hydraulic servo actuator is fixed in the middle of the portal steel structure reaction frame and extends downward into the main body of the environmental chamber. The force transmission component is located at the lower end of the hydraulic servo actuator and cooperates with the specimen. The multi-field coupling measurement and control system includes an electrical control cabinet, which contains a PLC controller. The PLC controller is connected to a touch screen and a host computer. The auxiliary support system includes an exhaust purification unit, a media circulation unit, and a maintenance and repair unit to ensure long-term stable operation of the device; the exhaust purification unit is connected to the interior of the main body of the environmental chamber.

2. The environmental simulation test device for FRP-reinforced concrete beams considering multi-factor coupling as described in claim 1, characterized in that: The main body of the environmental chamber is a double-layer insulated stainless steel chamber. The top of the main body of the environmental chamber is equipped with a sealed top cover. The side walls of the main body of the environmental chamber are equipped with observation windows and specimen loading and unloading doors. The bottom of the chamber is equipped with a medium collection tank and a drain valve.

3. The environmental simulation test device for FRP-reinforced concrete beams considering multi-factor coupling as described in claim 1, characterized in that: The freeze-thaw cycle module includes an immersion evaporator, an electric heating element, a refrigerant circulation unit, and a freeze-thaw controller. The immersion evaporator and the electric heating element are both located inside the main body of the environmental chamber. The refrigerant circulation unit is connected to the immersion evaporator, and the freeze-thaw controller is connected to the immersion evaporator and the electric heating element respectively.

4. The environmental simulation test device for FRP-reinforced concrete beams considering multi-factor coupling as described in claim 1, characterized in that: The corrosion medium module includes a salt spray generating unit, a medium immersion unit, and a gas corrosion unit; the output end of the salt spray generating unit extends into the main body of the environmental chamber, the medium immersion unit is located at the bottom of the main body of the environmental chamber, and the gas corrosion unit is connected to the interior of the main body of the environmental chamber through a gas distributor.

5. The environmental simulation test device for FRP-reinforced concrete beams considering multi-factor coupling as described in claim 1, characterized in that: The hydraulic servo actuator has a rated load capacity of ≥500kN, an output load frequency of 0.1~10Hz, and a load control accuracy of ±0.1%FS.

6. The environmental simulation test device for FRP-reinforced concrete beams considering multi-factor coupling as described in claim 1, characterized in that: The force transmission assembly includes a force sensor, a displacement gauge, a distribution beam, a ball joint support, and an adjustable support arranged sequentially from top to bottom. An FRP-reinforced concrete beam specimen is placed between the distribution beam and the ball joint support. The adjustable support is fixed to the bottom of the main body of the environmental chamber. The distribution beam and the ball joint support cooperate with each other.

7. The environmental simulation test device for FRP-reinforced concrete beams considering multi-factor coupling as described in claim 1, characterized in that: The multi-field coupling measurement and control system is equipped with overload protection, over-temperature protection, medium leakage protection and power failure protection modules. The data acquisition frequency is 1Hz~100Hz, and the data is automatically stored in Excel or CSV format.

8. The environmental simulation test device for FRP-reinforced concrete beams considering multi-factor coupling as described in claim 1, characterized in that: The PLC controller is connected to the freeze-thaw cycle module, the corrosive medium module, the temperature and humidity control module, and the hydraulic servo actuator.

9. The environmental simulation test device for FRP-reinforced concrete beams considering multi-factor coupling as described in claim 2, characterized in that: The medium circulation unit includes a medium storage tank, which is connected to the corrosive medium module and the medium collection tank via a circulation pump.

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