Test method for exploring ideal working pressure range of air column under high pressure and heavy load

Abstract

The invention discloses a test method for exploring an ideal working pressure range of an air column under high pressure and heavy load, and the method comprises the steps: firstly fixing the air column, uniformly distributing a plurality of hanging points on the surface of the air column, inflating the air column to enable the working pressure of the air column to be the lower limit of a preset working pressure range, hanging a load on each hanging point, and after the load is hung, stopping the air column; the air column is inflated, and the working pressure is increased step by step; measuring, recording and analyzing the height of the hanging point in the middle from the ground after the working pressure is adjusted each time, and finding out a linear change interval of the hanging point in the middle, namely an ideal working pressure range. The method simulates the working pressure and the bearing load when the gas column works, can truly and accurately reflect the working state of the gas column, and guarantees the reality, effectiveness and reliability of subsequent tests.

Description

Technical Field

[0001] The invention belongs to the technical field of gas models, and in particular relates to a test method for exploring an ideal working pressure range of a gas column under high pressure and heavy load. Background Art

[0002] Due to the heavy snowfall in the northern region that had not been seen in 10 years, a large amount of snow adhered to the surface of a single air column of a certain type of air canopy. The snow's own weight was greater than the working pressure inside the air column, resulting in the air column's own insufficient stiffness and resulting in collapse.

[0003] The working pressure of the gas column is set according to the design technical conditions and the statistical snowfall data in the past ten years. There are the following problems:

[0004] ①During the design and development phase, the product was designed based on the snowfall in the past ten years as a technical indicator, without accurately assessing the impact of heavy snow on the air column. Due to heavy snowfall, the weight of the air shed increased sharply, the actual load was greater than the design estimate, and the preset working pressure did not match the actual work, causing the air column to collapse or be damaged.

[0005] ② The work pressure does not set up two different working modes for summer and winter according to the temperature, rain, snow and other meteorological conditions throughout the year. Summary of the invention

[0006] Purpose of the Invention

[0007] In view of the above problems of the existing gas columns, the present invention provides a test method for exploring the ideal working pressure range of the gas column under high pressure and heavy load.

[0008] Inventing technical solutions

[0009] An experimental method for exploring the ideal working pressure range of an air column under high pressure and heavy load, wherein the method first fixes the air column, evenly distributes a number of hanging points on the surface of the air column, inflates the air column so that the working pressure of the air column is the lower limit of a preset working pressure range, hangs a load on each hanging point, and after the load is hung, inflates the air column to increase the working pressure step by step; after each adjustment of the working pressure, the height of the middle hanging point (if the number of hanging points is an odd number, the middlemost hanging point is measured, and if the number of hanging points is an even number, the two middlemost hanging points are measured) from the ground is measured and recorded and analyzed to find the linear change interval of the middle hanging point, which is the ideal working pressure range.

[0010] Preferably, the load is suspended from the middle to both sides.

[0011] Preferably, a plurality of pressure measuring nozzles are arranged on the surface of the gas column, and the pressure measuring nozzles are used to monitor the pressure changes inside the gas column in real time.

[0012] Preferably, the air column is inflated by controlling the fan through a PLC system.

[0013] Preferably, the fan speed is collected through a proximity switch, and the fan speed is converted into a corresponding pulse signal and transmitted to the PLC controller.

[0014] Preferably, before hanging the load, the load is converted according to the technical conditions of the air column and the snow load analysis, and the test load of each hanging point is designed.

[0015] Preferably, if the air column shows obvious crushing after a load is hung on it at the lower limit of the working pressure range, the upper and lower limits of the working pressure range of the air column are increased, the load is hung on the air column again and subsequent tests are carried out until the ideal working pressure range is found.

[0016] Preferably, the analysis method is: plotting multiple sets of test data into a line graph and analyzing the height change trend of the middle hanging point from the ground, finding the ideal working pressure range under the load based on the linear crossover range of the multiple sets of test data, and the test data are the working pressure and the height of the middle hanging point from the ground under the corresponding working pressure.

[0017] Preferably, a high-pressure heavy-load test is conducted after the preset working pressure range test is completed. High-pressure heavy-load test: Based on the product design technical requirements, it is a supplementary test after the ideal working pressure and load test of the product to increase the pressure and load that the product can withstand during normal operation. This test mainly verifies the safety and reliability of the ideal pressure and load design.

[0018] Preferably, the process of designing the test load for each hanging point includes the following steps:

[0019] (1) A coordinate system is established with the span width of the inflatable shed as the X-axis, the midpoint of the span width as the origin O, the arch height as the Y-axis, and the length direction of the shed as the Z-axis, and the basic equation of the aerodynamic form of the inflatable shed is obtained:

[0020] x 2 +(y+a) 2 =R 2

[0021] y=Ra,x=0

[0022]

[0023] (2) Calculate the projected area S of the inflatable shed body T :

[0024]

[0025] Among them, L is the span width of the shed, R is the arch radius of the shed; Δr is the radius of the air column;

[0026] (3) Calculate the standard value of snow load S in the vertical direction of the projection surface of the inflatable shedK :

[0027] S K =μ r S0

[0028] Among them, μ r is the roof snow distribution coefficient, S0 is the basic snow pressure;

[0029] (4) The projected snow load on the inflatable shed is F X ; The projected snow load on each air column is F X1 , Fx1 is evenly distributed on n hanging points, and the load of each hanging point is Fx2.

[0030] F X =S K S T

[0031]

[0032] Advantages of the present invention:

[0033] 1) Real simulation of the working state of the gas column

[0034] This method simulates the working pressure and load of the gas column when it is working, and can truly and accurately reflect the working state of the gas column, ensuring the authenticity, effectiveness and reliability of subsequent tests.

[0035] 2) Quantitative testing and analysis

[0036] The control variable method is used to ensure the single variable principle, the test data is quantitatively tested and recorded, the test data is sorted and drawn into a line graph, and the trend of the line graph is observed and analyzed to find out the linear change range.

[0037] 3) Extreme pressure test

[0038] On the basis of the working pressure test, an ultimate pressure test is added. Through the ultimate pressure test, the accuracy and reliability of the selected working pressure range are verified.

[0039] 4) Scientific validity of the test method

[0040] The test adopts methods such as controlled variables and quantitative analysis, takes real data from the field as the test basis, improves the working quality of the product, and provides a scientific and ideal test method for inflatable products. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 The figure is a connection diagram of the equipment used in a test method for exploring the ideal working pressure range of a gas column under high pressure and heavy load.

[0042] Figure 2 It is a structural diagram of the pressure monitoring system.

[0043] Figure 3 Schematic diagram of the coordinate system for calculating the basic equations of the aerodynamic form of the inflatable shed.

[0044] Figure 4 Schematic diagram of snow load distribution on arch structure.

[0045] Figure 5 Schematic diagram of the test principle.

[0046] In the figure: 1. gas column; 2. bow tie; 3. pressure measuring nozzle; 4. valve; 5. fixed constraint module; 6. load; 7. pressure measuring nozzle; 8. hook. DETAILED DESCRIPTION

[0047] The present invention is achieved through the following technical solutions.

[0048] An experimental method for exploring the ideal working pressure range of an air column under high pressure and heavy load, the method first fixes the air column with a fixed constraint module and rigging, evenly distributes 25 hanging points on the surface of the air column, fills the working pressure of the air column to A Pa, starts hanging the load at each hanging point, and hangs from the middle to both sides. After the load is hung, the working pressure is increased step by step. The working pressure can be set manually, the PLC system controls the fan to inflate, records and analyzes the height changes of 13 hanging points in each set of test data, finds the linear change interval of the hanging point, and then obtains the ideal working pressure range.

[0049] Three pressure measuring nozzles are designed on the surface of the gas column, and a redundant design is adopted to monitor the pressure changes inside the gas column in real time. The redundant design can ensure the accuracy of the monitoring data through pairwise comparison.

[0050] The proximity switch collects the fan speed, converts the fan speed into a corresponding pulse signal and transmits it to the PLC controller.

[0051] The control box is composed of a PLLC control system, a display screen and an operation panel. The operation panel can be used to design the working pressure range, which can meet the setting of multiple and large working ranges. The operation panel can also switch the control system to automatic and manual modes to meet the pressure adjustment during the test process.

[0052] The method specifically comprises the following steps:

[0053] 1) Set the test load

[0054] ① Analyze and convert the load according to the technical conditions of the air column and the amount of snow load, and design the test load for each hanging point.

[0055] 2) Preset working pressure range

[0056] ①After each hanging point is loaded with the specified test load, preset the working pressure range, and then adjust the pressure step by step from low to high. After each pressure adjustment, let it stand for 10 minutes, measure and record the height of the 13th hanging point (25 hanging points) from the ground, and collect and analyze the data.

[0057] ② Load correction test: According to the field test, if the preset working pressure range in ① is inaccurate, the gas column will be obviously crushed at the lower limit of the working pressure range, and the surface stiffness of the gas column will be insufficient at the upper limit of the working pressure range. At this time, it is necessary to increase the upper and lower limits of the working pressure range of the gas column and repeat the test step ① until the ideal working pressure range is found after multiple tests.

[0058] 3) Statistical analysis of test data

[0059] Multiple groups of test data are summarized, organized and analyzed, drawn into a line graph and their changing trends are analyzed. According to the linear crossover range of multiple groups of test data, the ideal working pressure range under the load is found.

[0060] If the air shed is used in Hebei, it is found that there may be gusts of level 11 in the area. The wind speed parameter should be considered as the maximum wind speed condition of level 11 during design. The air shed is used for 5 years and is designed as a temporary building. GB 50009-2012 "Code for Loads on Building Structures", considering the characteristics of the air shed and the use environment, the load calculation of the air shed is mainly to calculate the snow load.

[0061] Design principle:

[0062] The main pneumatic component of the inflatable shed is the shed body. The coordinate system is established with the span width as the X-axis, the midpoint of the span width as the origin O, the arch height as the Y-axis, and the length direction of the shed as the Z-axis. The coordinate system diagram is shown in Figure 3 .

[0063] The basic equation of the pneumatic form of the inflatable shed is obtained as follows:

[0064] x 2 +(y+a) 2 =R 2

[0065] y=Ra(x=0)

[0066]

[0067] Through repeated iterative calculation, the value of a is 2813mm, and R is 12813mm.

[0068] L——Span width 25000mm

[0069] R——Arch radius 12813mm

[0070] Δr——Radius of air column 1000mm

[0071] Projected area S of the inflatable shed T :

[0072]

[0073] Snow load calculation

[0074] Standard value of snow load S in the vertical direction of the projection surface of the inflatable shed K :

[0075] S K =μ r S0=140N / m 2

[0076] μ r ——Roof snow distribution coefficient 0.4, see Figure 4 .

[0077] S0——Basic snow pressure 0.35kN / m 2 , refer to the 50-year snow pressure value in Hebei in GB 50009.

[0078] Then the projected snow load F of the large inflatable shed is X ; Projected surface snow load F of each air column X1 , Fx1 snow load is evenly distributed on 25 hanging points, and the load on each hanging point is Fx2.

[0079] F x =S K S T =140000N

[0080] (As shown in the figure, it is pushed out from a 60° angle)

[0081]

[0082] Test Principle

[0083] The projection size of a single air column of the main body of the air canopy is 40m×29m, and the projection size of a single air column of each main body is 2m×25m (the angle of the projection ground at about 2m on both sides is relatively large relative to the ground, and the amount of snow is small, so it is not calculated. Figure 5 After the snow stopped, the on-site staff randomly selected three unit air columns on the air canopy, selected three one-square-meter areas above each air column, and then weighed the snow in the area, recorded the data and calculated the average value. The on-site measurement test data was about 10kg / m 2 , the actual maximum snow load of this single air column is about 500kg. The calculation formula is H = M / S*ρ, F = SK *S, M - weight of snow; S - area of ​​snow measured; H - thickness of snowfall; S K ——Standard value of snow load S K ; ρ——density of new snow is 0.05~0.10g / cm 3 (Take 0.07 when snow has just started).

[0084] The average snowfall thickness H is calculated to be about 15 mm. According to the standard value of snow load S K The theoretical maximum snow load is about 700kg.

[0085] Example

[0086] This test method has been successfully applied to a large inflatable air canopy in the north, solving the problem of the northern air canopy being crushed due to heavy snow, providing a wider working environment for inflatable model products, and improving the quality of inflatable model products.

[0087] In this embodiment, the main body of the air column is an arched structure, which is composed of 25 pieces with a diameter of 2m. The pieces are made of PVC material and are processed by splicing and heat sealing. The charging and discharging ports, pressure measuring nozzles, and fans are all finished products. A bow tie is attached to the surface of the air column, which mainly plays the role of bearing loads and fixed constraints. Bottom fixed constraint: Fixed constraint modules are used on both sides of the air column to clamp it. The control chassis consists of a PLC control system, a display screen, and an operation panel. The operation panel can set the working pressure range, which can meet the working range of multiple intervals and large intervals; the operation panel can also switch the control system to automatic and manual modes to meet the pressure adjustment during the test process.

[0088] In this test, the air column is set up about 500m next to a greenhouse. The surrounding area should be open and free of obstacles. The ground should be hardened and smooth with cement. The test air column should be set up and work at the same time as the greenhouse. The test process is as follows:

[0089] 1) After the gas column is inflated to the specified pressure, it is erected using a crane.

[0090] 2) Use fixed restraint modules inside and outside the bottom of the air column to secure it.

[0091] 3) One end of the ground mooring rigging is connected to the inner and outer bow knots on the surface of the gas column, and the other end is connected to the ground bolt.

[0092] 4) The control box and the fan are connected to the air column to control the working pressure range of the air column.

[0093] 5) Keep the working pressure of the air column consistent with the working pressure of the greenhouse, and monitor the status of the air column and greenhouse in real time.

[0094] Test results:

[0095] 1) The gas column is mounted with a specified load and works within the specified pressure range. The gas column is in good condition.

[0096] 2) Different working pressure ranges are formulated according to the temperature conditions in different seasons and rainy and snowy weather throughout the year, and the working status of the air column and greenhouse is well fed back.

[0097] 3) Regularly take the surface pieces of the air column (size 200×200) mm and repair them, measure the remaining strength of the air column material, and ensure the safe operation of the air column.

[0098] The protection scope of the present invention is not limited to the above-mentioned embodiments. Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the scope of the present invention. If these changes and modifications fall within the scope of the claims of the present invention and their equivalents, the present invention is intended to include these changes and modifications.

Claims

1. A test method for exploring the ideal working pressure range of a gas column under high pressure and heavy load, characterized in that: The method first fixes the air column, evenly distributes a number of hanging points on the surface of the air column, inflates the air column so that the working pressure of the air column is at the lower limit of a preset working pressure range, hangs a load on each hanging point, and after the load is hung, inflates the air column to increase the working pressure step by step; after each adjustment of the working pressure, the height of the hanging point in the middle from the ground is measured and recorded and analyzed to find the linear change interval of the hanging point in the middle, which is the ideal working pressure range.

2. A test method for exploring the ideal working pressure range of a gas column under high pressure and heavy load as claimed in claim 1, characterized in that: When hanging the load, hang from the center to both sides.

3. A test method for exploring the ideal working pressure range of a gas column under high pressure and heavy load as claimed in claim 1, characterized in that: A number of pressure gauges are arranged on the surface of the gas column, and the pressure gauges are used to monitor the pressure changes inside the gas column in real time.

4. A test method for exploring the ideal working pressure range of a gas column under high pressure and heavy load as claimed in claim 1, characterized in that: The fan is controlled by the PLC system to inflate the air column.

5. A test method for exploring the ideal working pressure range of a gas column under high pressure and heavy load as claimed in claim 4, characterized in that: The fan speed is collected through the proximity switch, and the fan speed is converted into a corresponding pulse signal and transmitted to the PLC controller.

6. A test method for exploring the ideal working pressure range of a gas column under high pressure and heavy load as claimed in claim 1, characterized in that: Before hanging the load, the load is converted according to the technical conditions of the air column and the snow load analysis, and the test load for each hanging point is designed.

7. A test method for exploring the ideal working pressure range of a gas column under high pressure and heavy load as claimed in claim 6, characterized in that: If the air column shows obvious crushing after the load is hung on it at the lower limit of the working pressure range, then increase the upper and lower limits of the working pressure range of the air column, hang the load on the air column again and conduct subsequent tests until the ideal working pressure range is found.

8. A test method for exploring the ideal working pressure range of a gas column under high pressure and heavy load as claimed in claim 1, characterized in that: The analysis method is: plot multiple sets of test data into a line graph and analyze the changing trend of the height of the middle hanging point from the ground. According to the linear crossover range of multiple sets of test data, the ideal working pressure range under the load is found. The test data are the working pressure and the height of the middle hanging point from the ground under the corresponding working pressure.

9. A test method for exploring the ideal working pressure range of a gas column under high pressure and heavy load as claimed in claim 1, characterized in that: After the preset working pressure range test is completed, a high pressure heavy load test is carried out.

10. A test method for exploring the ideal working pressure range of a gas column under high pressure and heavy load as claimed in claim 6, characterized in that: The process of designing the test load for each attachment point includes the following steps: (1) A coordinate system is established with the span width of the inflatable shed as the X-axis, the midpoint of the span width as the origin O, the arch height as the Y-axis, and the length direction of the shed as the Z-axis, and the basic equation of the aerodynamic form of the inflatable shed is obtained: x 2 +(y+a) 2 =R 2 y=Ra,x=0 (2) Calculate the projected area S of the inflatable shed body T : Among them, L is the span width of the shed, R is the arch radius of the shed; Δr is the radius of the air column; (3) Calculate the standard value of snow load S in the vertical direction of the projection surface of the inflatable shed K : S K =μ r S0 Among them, μ r is the roof snow distribution coefficient, S0 is the basic snow pressure; (4) The projected snow load on the inflatable shed is F X ; The projected snow load on each air column is F X1 , Fx1 is evenly distributed on n hanging points, and the load of each hanging point is Fx2. F X =S K S T

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