Membrane structure test device for applying normal load and load simulation method

Abstract

The invention discloses a membrane structure test device for applying a normal load and a load simulation method, and relates to the field of membrane structure test equipment.The box structure main frame of the device is constructed by welding light-weight thin-wall steel, orthogonal stiffened rib plates are welded to side sealing plates on the periphery, one end of the device is connected with a membrane structure test piece, and the other end of the device is connected with the membrane structure test piece; the side surface is connected with a pressure acquisition-control module through an air pipe, and a sealing gasket at the joint is reinforced; the pressure acquisition-control module is connected with the pneumatic valve module through a signal data line, two ends of the pneumatic valve module are connected with the test box and the air source module to form an air path, the pressure in the test box is adjusted through air inflation or air exhaust, and accurate and uniformly distributed normal load is applied. The adjustable pressure difference between the inside and the outside of the box body is formed through air exhaust and air inflation, the normal uniform load acts on the flexible membrane surface structure, the pressure in the test box is monitored in real time, rapid conversion of air inflation and air exhaust and fine dynamic adjustment of different flow rates are achieved, the technical principle is simple and reliable, the applicability is high, and the expansion applicability is high.

Description

Technical Field

[0001] The invention relates to the field of membrane structure test equipment, and in particular to a membrane structure test device for applying a normal load and a load simulation method. Background Art

[0002] For tensile and inflatable membrane structures, engineers often evaluate their true structural behavior and mechanical properties through load tests. In the prior art, integrated test equipment combining plane and saddle-shaped tensile membrane structures with measurement tools has been widely used in the structural behavior and performance testing of tensile membrane structures.

[0003] In terms of membrane structure test equipment, Liu Changjiang and others invented a saddle-shaped membrane structure test device (CN201810163170), which can adjust the span-ratio of the saddle-shaped membrane structure and measure the stress condition of the saddle-shaped membrane structure under different span-ratios; Ma Anqi and others invented a dual-purpose test device for saddle and plane membrane structures (CN202211052746), which is suitable for plane structure tests and saddle membrane structure tests, and can flexibly adjust the span-ratio of the saddle-shaped membrane structure and monitor the stress condition by adding cross bars in the design; Ma Yue and others invented a tensile membrane structure experimental device combined with photogrammetry (CN202210012254), which is suitable for obtaining the displacement and deformation of the thin film structure during the tensile membrane structure test; Ma Xiaowu and others invented a spatial membrane structure test device (CN201810815406), which is suitable for precise displacement measurement of specific membrane surface points during the tensile membrane structure test. The above-mentioned test devices are all suitable for installing and tensioning small-sized tensile flat membrane structures. The test methods only focus on the shape measurement and tension measurement of the tensile forming, and it is also impossible to carry out load tests on the tensile membrane structures.

[0004] In terms of uniform load application equipment, Dong Xinping et al. invented a precise application device for normal uniform pressure in indoor model tests (CN202020593319), which applies normal uniform pressure to the test structure by converting the weight of the counterweight block into oil pressure in the hollow film structure. The device can only apply normal pressure to structures of specific shapes and sizes, and cannot test larger structures and cannot load normal phase suction. Ouyang Yu et al. invented a loading device for simulating uniform load (CN201721900168), which injects water into the designed enclosure and impermeable film through a designed drainage mechanism to achieve simulated uniform loading on the surface of the specimen; Ye Shenghua et al. designed a uniform load loading system (CN202321709512), which applies a uniform load to the lower components through a water bag filled with water through a receiving tank. The above two methods overcome the problems of efficiency, accuracy and safety in laying heavy objects, but they can only achieve uniform loading in the direction of gravity, and cannot achieve normal loading of curved structures. Li Ming et al. designed a test device for a shaped airbag and a uniformly distributed load applied to a plate (CN 201520808985). The device simulates the situation where a plate is subjected to a uniformly distributed load by using the principle that a closed gas transfers the same pressure to the shaped airbag in all directions. However, the device is only applicable to load tests on flat plates of a specific size and cannot perform corresponding tests on curved structures.

[0005] In summary, the current test equipment for membrane structures is concentrated on the tensioning forming, deformation and tension detection of tensioned membrane structures. The test equipment for uniformly distributed normal load is limited to plane structures, shapes and sizes, and can only achieve simple static loading. It is impossible to conduct tests on other membrane structures (such as inflatable air pillow membrane structures), and it is impossible to achieve load changes and loading of normal suction loads.

[0006] Therefore, technicians in this field are committed to developing a membrane structure testing device and load simulation method for applying normal loads. They hope that the device can realize the accurate application of normal suction and pressure loads on the flexible membrane surface of various membrane structures such as tensioned membranes and air pillows, and have the ability to simulate quasi-static and dynamic loads, thus overcoming the difficulties of stacking loads, multi-point loading, etc., which cannot accurately control the normal direction and real-time dynamic control. Summary of the invention

[0007] In view of the above-mentioned defects of the prior art, the technical problem to be solved by the present invention is that the loading of the flexible membrane surface structure is mostly carried out by stacking loading and multi-point loading, which can only roughly approximate the uniformly distributed normal load and cannot achieve accurate membrane surface normal loading.

[0008] To achieve the above object, the present invention provides a membrane structure test device for applying normal load, comprising a steel structure test box, a pressure acquisition-control module, a pneumatic valve module, an air source module and a membrane structure specimen, wherein:

[0009] The main frame of the box structure of the steel structure test box is configured to be welded and constructed with light-weight thin-walled steel materials, orthogonal stiffening ribs are welded to the side sealing plates around the steel structure test box, the first end of the steel structure test box is connected to the membrane structure test piece, the side of the steel structure test box is connected to the pressure collection-control module through an air pipe, and silicone sealing pads are provided at the connection between the steel structure test box and the membrane structure test piece, and between the steel structure test box and the pressure collection-control module and are fastened with bolts;

[0010] The pressure acquisition-control module is connected to the pneumatic valve module via a signal data line. The two ends of the pneumatic valve module are respectively connected to the steel structure test box and the air source module via air pipes to form an air circuit. The internal pressure of the steel structure test box is quickly adjusted by inflation or exhaust, forming an internal and external pressure difference acting on the membrane structure specimen, thereby applying an accurately evenly distributed normal load.

[0011] Furthermore, the steel structure test box includes a square C-shaped steel ring beam, a thin-walled square steel pipe, a thin steel plate, an orthogonal stiffening rib plate, a universal caster, a steel box door and a metal hinge, wherein:

[0012] The square C-shaped steel ring beam is arranged at the front and rear ends of the steel structure test box to form the main frame of the steel structure test box;

[0013] The thin-walled square steel pipes are distributed at the four corners of the square C-shaped steel ring beam and vertically connected to the square C-shaped steel ring beam by welding;

[0014] The thin steel plates are distributed on the upper, lower, left and right sides of the main frame of the steel structure test box, and the thin-walled square steel tubes and the square C-shaped steel ring beams are connected by welding to form the steel structure box; the orthogonal stiffening ribs are arranged on the surface of the thin steel plates to improve the out-of-plane stiffness of the thin steel plates;

[0015] The universal casters are distributed around the bottom of the main frame of the steel structure test box and are connected to the front and rear ends of the thin-walled square steel pipe at the bottom by welding;

[0016] The steel box door is connected to the rear side of the main frame of the steel structure test box through the metal hinge.

[0017] Furthermore, the pressure acquisition-control module includes an air pressure sensor, an industrial control card and a processor, wherein:

[0018] The air pressure sensor has a first end connected to the steel structure test box through an air pipe, and a second end connected to the input end of the industrial control card through a signal line;

[0019] The industrial control card is connected to the processor, transmits pressure information to the processor, receives valve update instructions from the processor, and outputs valve adjustment instructions to the pneumatic valve module through the output end of the industrial control card.

[0020] Furthermore, the pneumatic valve module includes a flow regulating submodule and an air path conversion submodule, the flow regulating submodule and the air path conversion submodule are connected via an air pipe, the air pipe layout of the flow regulating submodule is set as multiple branch air paths converging into a main air path, the flow regulating submodule realizes air volume control of the branch air paths and the converging main air paths, the air pipe layout of the air path conversion submodule is set as two branch air paths converging into a main air path, and the air path conversion submodule is set as that when the air source is not connected to the air path, the membrane structure testing device can be connected to the atmosphere to maintain normal operation.

[0021] Furthermore, the flow regulating submodule includes a first normally open solenoid valve, a first branch confluence three-way joint, a first main confluence three-way joint and an electric proportional valve. Each branch gas circuit in the flow regulating submodule is provided with the first normally open solenoid valve, one end of the first normally open solenoid valve is connected to the steel structure test box through an air pipe, the other end of the first normally open solenoid valve is connected to the first branch confluence three-way joint through an air pipe, and then connected to the first main confluence three-way joint through an air pipe to realize multi-branch confluence to the main pipe, and the first main confluence three-way joint is connected to the electric proportional valve through an air pipe.

[0022] Furthermore, the gas circuit conversion submodule includes a second normally open solenoid valve, a second branch confluence three-way joint, a second main confluence three-way joint and a normally closed solenoid valve, one end of the main pipe of the second branch confluence three-way joint is connected to the gas source module, a branch pipe of the second branch confluence three-way joint is connected to the second normally open solenoid valve through an air pipe, and the other end of the second normally open solenoid valve is connected to the atmosphere; the other end branch pipe of the second branch confluence three-way joint is connected to the normally closed solenoid valve through an air pipe, and the other end of the normally closed solenoid valve is connected to the branch pipe of the second main confluence three-way joint through an air pipe.

[0023] Furthermore, the air source module comprises a vacuum pump and an air compressor, and the vacuum pump and the air compressor are respectively connected to two air paths of the air path conversion submodule through air pipes.

[0024] Furthermore, the membrane structure specimen includes a membrane structure, an aluminum alloy profile clamp and a silicone sealing gasket. The aluminum alloy profile clamp is used to install the membrane structure specimen in the steel structure test box. The aluminum alloy profile clamp is fixedly connected to the steel structure test box by fastening bolts, and the silicone sealing gasket is arranged between the aluminum alloy profile clamp and the steel structure test box.

[0025] On the other hand, the present invention further provides a membrane structure load simulation method for applying a normal load, the method using a membrane structure test device for applying a normal load provided by the present invention to simulate applying a normal load to the membrane structure specimen, the method comprising the following steps:

[0026] S1: Install the membrane structure specimen and the aluminum alloy profile fixture, and use bolts to fasten the aluminum alloy profile fixture and silicone sealing gasket to the steel structure box;

[0027] S2: Close the steel box door, and fasten the steel box door and silicone sealing gasket to the steel structure box with bolts to form a sealed test box;

[0028] S3: Connect to the pressure acquisition-control module, input the steel structure test chamber task information and pressure sensor information, and start the logic control algorithm;

[0029] S4: Connect the pneumatic valve module;

[0030] S5: Start the vacuum pump and air compressor to start the test and perform load simulation loading.

[0031] Furthermore, in step S3, the logic control algorithm compares the air pressure of the steel structure test box collected in real time with the air pressure set in the task information, updates the valve action of the pneumatic valve module in real time, realizes air path conversion and air flow adjustment, and when the air pressure of the steel structure test box reaches the air pressure set in the task information, maintains or changes the pressure to realize simulated loading of static load and dynamic load.

[0032] In a preferred embodiment of the present invention, compared with the prior art, the present invention has the following beneficial effects:

[0033] 1. The present invention realizes accurate normal load loading of flexible membrane surface structures, can simulate normal suction and pressure loads of various membrane structures, and explore the structural behavior and mechanical properties of membrane structures under such loads;

[0034] 2. The present invention adopts thin-walled steel to weld and build the main frame of the test box. The thin-walled steel plates reinforced by welding orthogonal stiffening ribs are used to improve the strength and rigidity. The openings on the front and rear sides connecting the membrane structure test piece and the sealed box door adopt silicone sealing pads and use bolts to fasten to ensure the airtightness of the whole wall room. The larger-sized steel structure test box can have a large load test range, spacious internal equipment layout and observation space, and significantly improve the efficiency of filling and exhausting pressure adjustment;

[0035] 3. The present invention connects the four sides of the membrane structure specimen to the load box. The membrane structure specimen is modularized and can replace various membrane structures. It can conveniently implement various membrane structure tests, such as plane tension membrane, hyperbolic membrane surface, air pillow, etc.

[0036] 4. The present invention can realize the pseudo-dynamic and pulsating real-time dynamic control of flexible membrane structure loading, can realize the pseudo-static and dynamic load simulation of various membrane structures, and can be used to explore the structural performance of membrane structures under static progressive loads and the dynamic characteristics under pseudo-dynamic loads.

[0037] The concept, specific structure and technical effects of the present invention will be further described below in conjunction with the accompanying drawings to fully understand the purpose, characteristics and effects of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 This is a schematic diagram of the connection of modules of a membrane structure test device according to an embodiment of the present invention;

[0039] Figure 2 is a three-dimensional schematic diagram of a membrane structure test device according to an embodiment of the present invention;

[0040] Figure 3 is an assembly diagram of a membrane structure specimen of an embodiment of the present invention;

[0041] Figure 4 It is a top view of the membrane structure test piece assembly diagram of an embodiment of the present invention;

[0042] Figure 5 It is a logic control flow chart of the load simulation method in an embodiment of the present invention.

[0043] The descriptions of the various numbers in the figure are as follows:

[0044] 1-Steel structure test box, 101-Square C-shaped steel ring beam, 102-Thin-walled square steel pipe, 103-Thin steel plate, 104-Orthogonal stiffening rib plate, 105-Universal caster, 106-Steel box door, 107-Metal hinge;

[0045] 2-pressure acquisition-control module, 201-air pressure sensor, 202-industrial control card, 203-processor;

[0046] 3-pneumatic valve module, 31-flow regulating valve submodule, 311-first normally open solenoid valve, 312-first branch confluence three-way joint, 313-first trunk confluence three-way joint, 314-electric proportional valve, 32-gas circuit conversion valve submodule, 321-second normally open solenoid valve, 322-second branch confluence three-way joint, 323-second trunk confluence three-way joint, 324-normally closed solenoid valve;

[0047] 4-air source module, 401-vacuum pump, 402-air compressor;

[0048] 5-membrane structure specimen, 501-membrane structure, 502-aluminum alloy profile fixture, 503-silicone sealing gasket, 504-fastening bolts. DETAILED DESCRIPTION

[0049] The following describes several preferred embodiments of the present invention with reference to the drawings in the specification, so that the technical content is clearer and easier to understand. The present invention can be embodied in many different forms of embodiments, and the protection scope of the present invention is not limited to the embodiments mentioned in the text.

[0050] In the drawings, components with the same structure are indicated by the same numerical reference numerals, and components with similar structures or functions are indicated by similar numerical reference numerals. The size and thickness of each component shown in the drawings are arbitrarily shown, and the present invention does not limit the size and thickness of each component. In order to make the illustration clearer, the thickness of the components is appropriately exaggerated in some places in the drawings.

[0051] like Figure 1 As shown, a membrane structure test device for applying a normal load provided by an embodiment of the present invention adjusts the pressure of a sealed test box tightly mounted with a flexible membrane surface structure by evacuating and inflating air to form an adjustable pressure difference between the inside and outside of the box, and then acts on the flexible membrane surface structure in the form of a normal uniformly distributed load. The membrane structure test device includes a steel structure test box 1, a pressure acquisition-control module 2, a pneumatic valve module 3, an air source module 4 and a membrane structure specimen 5, wherein:

[0052] The main frame of the box structure of the steel structure test box 1 is welded and constructed with lightweight thin-walled steel. The side sealing plates around the steel structure test box 1 are welded with orthogonal stiffening ribs 104. One end of the steel structure test box 1 is connected to the membrane structure specimen 5. The side of the steel structure test box 1 is connected to the pressure collection-control module 2 through an air pipe. A silicone sealing pad 503 is set at the connection between the steel structure test box 1 and the membrane structure specimen 5 and the pressure collection-control module 2 and is fastened with bolts.

[0053] The pressure acquisition-control module 2 is connected to the pneumatic valve module 3 through a signal data line. The two ends of the pneumatic valve module 3 are respectively connected to the steel structure test box 1 and the air source module 4 through air pipes to form an air circuit. The internal pressure of the steel structure test box 1 is quickly adjusted by inflation or exhaust, forming an internal and external pressure difference acting on the membrane structure specimen 5, and applying an accurately evenly distributed normal load.

[0054] like Figure 2 , Figure 3 , Figure 4As shown, the steel structure test box 1 includes a square C-shaped steel ring beam 101, a thin-walled square steel pipe 102, a thin steel plate 103, an orthogonal stiffening rib plate 104, a universal caster 105, a steel box door 106 and a metal hinge 107.

[0055] A square C-shaped steel ring beam 101 is arranged at the front and rear ends of the steel structure test box 1 to form the main frame of the steel structure test box 1. The front side of the main frame is connected to the membrane structure specimen 5. A silicone sealing gasket 503 is arranged at the connection between the two and is fastened by fastening bolts 504 to form a closed test box.

[0056] The thin-walled square steel tubes 102 are distributed at the four corners of the square C-shaped steel ring beam 101, and a multi-distributed design is adopted. The square C-shaped steel ring beam 101 is vertically connected by welding to form the main frame of the steel structure test box 1, which aims to increase the volume of the box while reducing the weight of the box as much as possible;

[0057] The thin steel plates 103 are distributed on the upper, lower, left and right sides of the main frame of the steel structure test box 1, and are connected by welding to the thin-walled square steel tubes 102 and the square C-shaped steel ring beams 101 to form the steel structure box 1. The purpose is to enhance the overall rigidity and sealing of the steel structure box. Orthogonal stiffening ribs 104 are arranged on the surface of the thin steel plates 103 to improve the out-of-plane rigidity of the thin steel plates 103;

[0058] Universal casters 105 are distributed around the bottom of the main frame of the steel structure test box 1, and are connected to the front and rear ends of the thin-walled square steel pipe 102 at the bottom by welding, so as to provide the mobility of the steel structure box;

[0059] The steel box door 106 is connected to the rear side of the main frame of the steel structure test box 1 through a metal hinge 107. A silicone sealing pad 503 is provided at the connection between the two and is fastened by fastening bolts 504 to ensure the air tightness of the box.

[0060] like Figure 2 As shown, the pressure acquisition-control module 2 includes an air pressure sensor 201, an industrial control card 202 and a processor 203. One side of the air pressure sensor 201 is connected to the steel structure test box 1 through an air pipe, and the other side is connected to the input end of the industrial control card 202 through a signal line; the industrial control card 202 is connected to the processor 203, the industrial control card 202 transmits pressure information to the processor 203, and receives the update valve instruction of the processor 203, and outputs the valve adjustment instruction to the pneumatic valve module 3 through the output end of the industrial control card 202. The processor 203 can be a computer or other computer for industrial control purposes.

[0061] like Figure 2As shown, the pneumatic valve module 3 includes a flow regulating submodule 31 and an air path conversion submodule 32. The flow regulating submodule 31 and the air path conversion submodule 32 are connected via an air pipe. The air pipe layout of the flow regulating submodule 31 is set to multiple branch air paths converging into a main air path. The flow regulating submodule 31 realizes air volume control of the branch air paths and the converging main air paths. The air pipe layout of the air path conversion submodule 32 is set to two branch air paths converging into a main air path. The air path conversion submodule 32 is set to enable the membrane structure test device to be connected to the atmosphere to maintain normal operation when the air source is not connected to the air path.

[0062] The flow regulating submodule 31 includes a first normally open solenoid valve 311, a first branch confluence three-way joint 312, a first main confluence three-way joint 313 and an electric proportional valve 314. Each branch gas circuit in the flow regulating submodule 31 is provided with a first normally open solenoid valve 311. One end of the first normally open solenoid valve 311 is connected to the steel structure test box 1 through an air pipe, and the other end of the first normally open solenoid valve 311 is connected to the first branch confluence three-way joint 312 through an air pipe, and then connected to the first main confluence three-way joint 313 through an air pipe, so as to realize the confluence of multiple branches to the main pipe. The first main confluence three-way joint 313 is connected to the electric proportional valve 314 through an air pipe.

[0063] The flow regulating submodule 31 adopts this layout design for the following purposes:

[0064] 1) By controlling the opening and closing number of the first normally open solenoid valve 311 on the branch, the airflow control of the branch gas path is realized, and the rough control of the airflow of the converging main gas path is realized;

[0065] 2) By adjusting the electric proportional valve 314, the air flow of the converging main air path can be precisely controlled.

[0066] The gas circuit conversion submodule 32 includes a second normally open solenoid valve 321, a second branch confluence three-way joint 322, a second main confluence three-way joint 323 and a normally closed solenoid valve 324. One end of the main pipe of the second branch confluence three-way joint 322 is connected to the gas source module 4, and a branch pipe of the second branch confluence three-way joint 322 is connected to the second normally open solenoid valve 321 through an air pipe. The other end of the second normally open solenoid valve 321 is connected to the atmosphere. Its purpose is to be connected to the atmosphere to maintain normal operation when the gas source is not connected to the gas circuit; the other end of the branch pipe of the second branch confluence three-way joint 322 is connected to the normally closed solenoid valve 324 through an air pipe, and the other end of the normally closed solenoid valve 324 is connected to the second main confluence three-way joint branch pipe 323 through an air pipe. Its purpose is to realize the access of the inflation pipeline and the exhaust pipeline by controlling the valve opening and closing combination of the second normally open solenoid valve 321 and the normally closed solenoid valve 324 of the two branches without closing the gas source module 4.

[0067] like Figure 2As shown, the gas source module 4 includes a vacuum pump 401 and an air compressor 402. The vacuum pump 401 and the air compressor 402 are respectively connected to two gas paths of the gas path conversion submodule 32 through gas pipes to provide working gas for the entire device.

[0068] like Figure 4 As shown, the assembly diagram of the membrane structure specimen 5 in this embodiment, the membrane structure specimen 5 includes a membrane structure 501, an aluminum alloy profile fixture 502, a silicone seal 503 and a fastening bolt 504. The membrane structure 501 is installed on the aluminum alloy profile fixture 502, and the aluminum alloy profile fixture 502 on which the membrane structure specimen 501 is installed is connected to the steel structure test box 1 through the fastening bolt 504. A silicone seal 503 is arranged between the aluminum alloy profile fixture 502 and the steel structure test box 1 to ensure the airtightness of the sealed box.

[0069] The membrane structure test device for applying normal load provided by the embodiment of the present invention has the following characteristics compared with the prior art:

[0070] 1. Most of the existing flexible membrane surface structures are loaded by stacking or multi-point loading, which can only roughly approximate the uniformly distributed normal load and cannot achieve the problem of accurate normal loading of the membrane surface. The present invention can achieve accurate normal load loading of the flexible membrane surface structure. The present invention adopts the pneumatic pressure control principle, and forms a sealed test box by tightly connecting the membrane surface structure to the test box. The internal pressure of the sealed box is quickly adjusted by filling and exhausting air to form a pressure difference between the inside and outside of the membrane surface structure, thereby achieving an accurately uniformly distributed normal load. It can simulate the normal suction and pressure loads of various membrane structures, and explore the structural behavior and mechanical properties of the membrane structure under such loads.

[0071] 2. In order to achieve the problem of light weight, high strength, high rigidity and airtightness of a larger-sized (1.8×1.7×1.6m) sealed box, the present invention adopts thin-walled steel to weld and build the main frame of the test box; the thin-walled steel plates reinforced by welding orthogonal stiffening ribs on all sides are used to improve the strength and rigidity; silicone sealing pads are used at the openings on the front and rear sides to connect the membrane structure specimen and the sealed box door, and bolts are used to fasten them to ensure the airtightness of the overall wall room. The main frame of the box structure adopts light-weight thin-walled steel to ensure the structural integrity and obtain a larger internal space; the side sealing plates around the box are reinforced with thin-walled steel plates with stiffening ribs to ensure strength and rigidity; silicone sealing pads are set at the open connections on the front and rear sides to ensure airtightness, which can enable the larger-sized steel structure test box to have a large load test range, spacious internal equipment layout and observation space, and significantly improve the efficiency of filling and exhausting pressure adjustment.

[0072] 3. In view of the problems that the existing membrane structures are simple, single and have poor adaptability, the present invention connects the four sides of the membrane structure specimen with the load box. The membrane structure specimen is modular and can replace various membrane structures. By adopting modular and replaceable membrane structure specimens, various membrane structure tests can be easily realized, such as plane tensioned membrane, hyperbolic membrane surface, air pillow, etc.

[0073] With respect to the membrane structure test device for applying normal load provided by the present invention, the present invention also provides a membrane structure load simulation method for applying normal load based on the membrane structure test device. This method aims at the problem that the loading methods of flexible membrane structures in the prior art are currently static loading and cannot achieve dynamic adjustment and control. Through pseudo-dynamic and pulsating real-time dynamic control of flexible membrane structure loading, a pressure acquisition-control module is designed to monitor the internal pressure of the test box in real time and send a feedback signal to control the pneumatic valve group module according to a logic control algorithm, so as to achieve rapid conversion of inflation and exhaust and fine and dynamic adjustment of different flow rates, which can realize quasi-static and dynamic load simulation of various membrane structures, and can be used to explore the structural performance of membrane structures under static progressive loads and the dynamic characteristics under the action of pseudo-dynamic loads.

[0074] like Figure 5 As shown, the control flow and control logic of the membrane structure load simulation method provided in this embodiment. The user needs to first define the task information (task pressure size and task duration) and sensor information (accuracy and range) of each level of the test box in the running algorithm, and then the control logic starts to execute.

[0075] The specific steps include:

[0076] Step 1: Install the membrane structure specimen 501 and the aluminum alloy profile fixture 502, and use the fastening bolts 504 to fasten the aluminum alloy profile fixture 502 and the silicone sealing gasket 503 to the steel structure box 1;

[0077] Step 2: Close the steel box door 106, and use the fastening bolts 504 to fasten the steel box door 106 and the silicone sealing gasket 503 to the steel structure test box 1 to form a sealed test box;

[0078] Step 3: Connect to the pressure acquisition-control module 2, input the task information of the steel structure test box 1 and the information of the pressure sensor 201, and start the logic control algorithm;

[0079] Step 4: Connect the pneumatic valve module 3;

[0080] Step 5: Start the vacuum pump 401 and the air compressor 402 to start the test and perform load simulation.

[0081] In order to realize the simulated loading of quasi-static load and dynamic load, in step three, the logic control algorithm will compare the air pressure of the steel structure test box 1 collected in real time with the air pressure set in the task information, and update the valve action of the pneumatic valve module 3 in real time to realize the air path conversion and air flow adjustment, and when the air pressure of the steel structure test box 1 reaches the air pressure set in the task information, the pressure is maintained or changed, thereby realizing the simulated loading of quasi-static load and dynamic load.

[0082] In a preferred embodiment of the present invention, the logic control algorithm includes the following detailed steps:

[0083] 01. Obtain current task information (current target pressure P0 and duration △T) and sensor information;

[0084] 02. Read the measured pressure P of the air pressure sensor 202;

[0085] 03. Calculate the current pressure difference △P=P–P0;

[0086] 04. Is the pressure difference △P < 0? If yes, go to 05; otherwise, go to 06;

[0087] 05. The gas path conversion submodule 32 is converted into a charging gas path, and then go to 07;

[0088] 06. The gas path conversion submodule 32 is converted into a gas extraction gas path;

[0089] 07. Determine the opening and closing number of the first normally open solenoid valve 311 in the flow regulating submodule 31 according to the pressure difference ΔP, and determine the opening degree of the electric proportional valve 314 through the PID algorithm;

[0090] 08. Determine whether the pressure P measured by the air pressure sensor 202 satisfies the condition P∈[P0-e p ,P0+e p ]? If “yes”, go to 09, otherwise go to 02;

[0091] 09. Determine whether the timer is started? If yes, go to step 12, otherwise go to step 10;

[0092] 10. Determine whether the duration △T of the current task is zero? If yes, go to step 11, otherwise go to step 12;

[0093] 11. Timer starts, the duration is △T, go to 02;

[0094] 12. Check whether the timer has finished timing. If yes, go to 13, otherwise go to 02;

[0095] 13. Update the next level task information and go to 01.

[0096] In the logic control algorithm of the present embodiment, steps 02-08 compare the real-time collected air pressure of the steel structure test box 1 with the set task air pressure, and update the valve action of the pneumatic valve module 3 in real time according to the measured pressure to achieve air path conversion and air flow adjustment, in order to ensure that the pressure can gradually reach the target pressure, avoid overpressure and thus achieve accurate loading of a normal pressure of a specific magnitude; steps 08-11 provide an option of pressure maintenance and pressure change based on the target pressure being reached, and pressure maintenance can be used to achieve quasi-static load loading; pressure change can execute the next step of loading to achieve dynamic load simulation.

[0097] The membrane structure test device and load simulation method for applying normal load provided by the embodiment of the present invention have simple technical principles, are reliable and have strong applicability, have significant technical advantages, are easy to produce and implement, have outstanding performance indicators, can meet the needs of most flexible membrane structure tests, and have good industrial application prospects. Compared with the existing technology, it has more characteristics:

[0098] 1. Advantages of technical solutions

[0099] The technical solution provided by the embodiment of the present invention adjusts the pressure of the sealed test box with a tightly installed flexible membrane surface structure by vacuuming and inflating, forming an adjustable pressure difference between the inside and outside of the box, and then acts on the flexible membrane surface structure in the form of a normal uniformly distributed load. At the same time, by designing a pressure acquisition-control module, the internal pressure of the test box is monitored in real time, and a feedback signal is sent out according to the logic control algorithm to control the pneumatic valve group module, so as to realize the rapid conversion of inflation and vacuuming and the fine dynamic adjustment of different flow rates. The technical principle is simple, reliable, and highly applicable, and has strong expansion and application. For example: under the condition that the air tightness and strength stiffness meet the requirements, the size of the steel structure test box can be increased for load testing of larger or even full-scale flexible membrane surface structures; the corresponding valve system can be recombined and designed to realize load testing of multi-condition coupling.

[0100] 2. Performance indicators

[0101] Load test range: relative pressure ±50kPa (conservative estimate);

[0102] System loading performance: maximum loading speed 0.75kPa / s, unloading speed 0.5kPa / s, pressure maintenance error less than 0.05kPa;

[0103] System dynamic performance: valve feedback response rate up to 100Hz;

[0104] Sinusoidal waveform load: maximum amplitude 0.5kPa, frequency 0.3Hz.

[0105] 3. Production implementation

[0106] The system is easy to manufacture and implement. All components of the membrane structure test device provided by the embodiment of the present invention can be purchased through conventional channels, and no special processing equipment or instruments are required, and personnel without professional training can also assemble and install it by themselves.

[0107] The preferred specific embodiments of the present invention are described in detail above. It should be understood that a person skilled in the art can make many modifications and changes based on the concept of the present invention without creative work. Therefore, any technical solution that can be obtained by a person skilled in the art through logical analysis, reasoning or limited experiments based on the concept of the present invention on the basis of the prior art should be within the scope of protection determined by the claims.

Claims

1. A membrane structure test device for applying normal load, characterized in that: It includes a steel structure test box, a pressure acquisition-control module, a pneumatic valve module, an air source module and a membrane structure test piece, among which: The main frame of the box structure of the steel structure test box is configured to be welded and constructed with light-weight thin-walled steel materials, orthogonal stiffening ribs are welded to the side sealing plates around the steel structure test box, the first end of the steel structure test box is connected to the membrane structure test piece, the side of the steel structure test box is connected to the pressure collection-control module through an air pipe, and silicone sealing pads are provided at the connection between the steel structure test box and the membrane structure test piece, and between the steel structure test box and the pressure collection-control module and are fastened with bolts; The pressure acquisition-control module is connected to the pneumatic valve module via a signal data line. The two ends of the pneumatic valve module are respectively connected to the steel structure test box and the air source module via air pipes to form an air circuit. The internal pressure of the steel structure test box is quickly adjusted by inflation or exhaust, forming an internal and external pressure difference acting on the membrane structure specimen, thereby applying an accurately evenly distributed normal load.

2. The membrane structure testing device according to claim 1, characterized in that: The steel structure test box includes a square C-shaped steel ring beam, a thin-walled square steel pipe, a thin steel plate, an orthogonal stiffening rib plate, a universal caster, a steel box door and a metal hinge, wherein: The square C-shaped steel ring beam is arranged at the front and rear ends of the steel structure test box to form the main frame of the steel structure test box; The thin-walled square steel pipes are distributed at the four corners of the square C-shaped steel ring beam and vertically connected to the square C-shaped steel ring beam by welding; The thin steel plates are distributed on the upper, lower, left and right sides of the main frame of the steel structure test box, and the thin-walled square steel tubes and the square C-shaped steel ring beams are connected by welding to form the steel structure box; the orthogonal stiffening ribs are arranged on the surface of the thin steel plates to improve the out-of-plane stiffness of the thin steel plates; The universal casters are distributed around the bottom of the main frame of the steel structure test box and are connected to the front and rear ends of the thin-walled square steel pipe at the bottom by welding; The steel box door is connected to the rear side of the main frame of the steel structure test box through the metal hinge.

3. The membrane structure testing device according to claim 2, characterized in that: The pressure acquisition-control module includes an air pressure sensor, an industrial control card and a processor, wherein: The air pressure sensor has a first end connected to the steel structure test box through an air pipe, and a second end connected to the input end of the industrial control card through a signal line; The industrial control card is connected to the processor, transmits pressure information to the processor, receives valve update instructions from the processor, and outputs valve adjustment instructions to the pneumatic valve module through the output end of the industrial control card.

4. The membrane structure testing device according to claim 3, characterized in that: The pneumatic valve module includes a flow regulating submodule and an air path conversion submodule, the flow regulating submodule and the air path conversion submodule are connected via an air pipe, the air pipe layout of the flow regulating submodule is configured such that multiple branch air paths converge into a main air path, the flow regulating submodule realizes air volume control of the branch air paths and the converging main air paths, the air pipe layout of the air path conversion submodule is configured such that two branch air paths converge into a main air path, and the air path conversion submodule is configured such that when the air source is not connected to the air path, the membrane structure testing device can be connected to the atmosphere to maintain normal operation.

5. The membrane structure testing device according to claim 4, characterized in that: The flow regulating submodule includes a first normally open solenoid valve, a first branch confluence three-way joint, a first main confluence three-way joint and an electric proportional valve. Each branch gas circuit in the flow regulating submodule is provided with the first normally open solenoid valve, one end of the first normally open solenoid valve is connected to the steel structure test box through an air pipe, the other end of the first normally open solenoid valve is connected to the first branch confluence three-way joint through an air pipe, and then connected to the first main confluence three-way joint through an air pipe to realize the confluence of multiple branches to the main pipe, and the first main confluence three-way joint is connected to the electric proportional valve through an air pipe.

6. The membrane structure testing device according to claim 5, characterized in that: The gas circuit conversion submodule includes a second normally open solenoid valve, a second branch confluence three-way joint, a second main confluence three-way joint and a normally closed solenoid valve, one end of the main pipe of the second branch confluence three-way joint is connected to the gas source module, a branch pipe of the second branch confluence three-way joint is connected to the second normally open solenoid valve through an air pipe, and the other end of the second normally open solenoid valve is connected to the atmosphere; the other end branch pipe of the second branch confluence three-way joint is connected to the normally closed solenoid valve through an air pipe, and the other end of the normally closed solenoid valve is connected to the branch pipe of the second main confluence three-way joint through an air pipe.

7. The membrane structure testing device according to claim 6, characterized in that: The air source module comprises a vacuum pump and an air compressor, and the vacuum pump and the air compressor are respectively connected to two air paths of the air path conversion submodule through air pipes.

8. The membrane structure testing device according to claim 7, characterized in that: The membrane structure specimen includes a membrane structure, an aluminum alloy profile clamp and a silicone sealing gasket. The aluminum alloy profile clamp is used to install the membrane structure specimen in the steel structure test box. The aluminum alloy profile clamp is fixedly connected to the steel structure test box by fastening bolts, and the silicone sealing gasket is arranged between the aluminum alloy profile clamp and the steel structure test box.

9. A membrane structure load simulation method for applying normal load, characterized in that: The method uses the membrane structure test device according to any one of claims 1 to 8 to simulate applying a normal load to the membrane structure specimen, and the method comprises the following steps: S1: Install the membrane structure specimen and the aluminum alloy profile fixture, and use bolts to fasten the aluminum alloy profile fixture and silicone sealing gasket to the steel structure box; S2: Close the steel box door, and fasten the steel box door and silicone sealing gasket to the steel structure box with bolts to form a sealed test box; S3: Connect to the pressure acquisition-control module, input the steel structure test chamber task information and pressure sensor information, and start the logic control algorithm; S4: Connect the pneumatic valve module; S5: Start the vacuum pump and air compressor to start the test and perform load simulation loading.

10. The membrane structure load simulation method according to claim 9, characterized in that: In step S3, the logic control algorithm compares the air pressure of the steel structure test box collected in real time with the air pressure set in the task information, updates the valve action of the pneumatic valve module in real time, realizes air path conversion and air flow adjustment, and when the air pressure of the steel structure test box reaches the air pressure set in the task information, maintains or changes the pressure to realize simulated loading of quasi-static load and dynamic load.

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