An experimental method for exploring the ideal working pressure range of a gas column under high pressure and heavy load.

Abstract

This invention discloses an experimental method for exploring the ideal working pressure range of an air column under high pressure and heavy load. The method involves first fixing the air column and evenly distributing several hanging points on its surface. The air column is then inflated to bring its working pressure to the lower limit of a preset working pressure range. A load is suspended from each hanging point. After the load is fully suspended, air is inflated into the air column, gradually increasing the working pressure. After each pressure adjustment, the height of the middle hanging point from the ground is measured and recorded, and the results are analyzed to identify the linear variation range of the middle hanging point, which represents the ideal working pressure range. This method simulates the working pressure and load of the air column during operation, accurately reflecting its working state and ensuring the authenticity, effectiveness, and reliability of subsequent experiments.

Description

Technical Field

[0001] This invention belongs to the field of air model technology, and in particular relates to an experimental method for exploring the ideal working pressure range of an air column under high pressure and heavy load. Background Technology

[0002] Due to the heavy snowfall unseen in 10 years in northern regions, a large amount of snow accumulated on the surface of a certain type of inflatable roof column. The weight of the column exceeded the internal working pressure, resulting in insufficient rigidity and subsequent collapse.

[0003] The working pressure of this air column is set based on design technical conditions and snowfall data statistics from the past ten years, and it has the following problems:

[0004] ① During the design and development phase, this product was based on snowfall data from the past ten years as its design technical specifications, without accurately assessing the impact of blizzards on the air column. Heavy snowfall caused a sharp increase in the weight of the air canopy, resulting in an actual load exceeding the design estimate. This mismatch between the preset working pressure and the actual working pressure led to air column collapse or damage.

[0005] ② The work pressure was not adjusted according to the temperature and weather conditions such as rain and snow throughout the year, and there were no different work modes for summer and winter. Summary of the Invention

[0006] Purpose of the invention

[0007] To address the aforementioned problems with existing air columns, this invention provides an experimental method for exploring the ideal working pressure range of an air column under high pressure and heavy load.

[0008] Invention Technology Solutions

[0009] An experimental method for exploring the ideal working pressure range of an air column under high pressure and heavy load involves first fixing the air column and evenly distributing several hanging points on its surface. The air column is then inflated to a working pressure equal to the lower limit of the preset working pressure range. A load is suspended from each hanging point. After the load is fully suspended, air is inflated into the air column, gradually increasing the working pressure. After each pressure adjustment, the height of the middle hanging point (if the number of hanging points is odd, the middle hanging point is measured; if the number of hanging points is even, the two middle hanging points are measured) from the ground is measured and analyzed. The linear variation range of the middle hanging point is then identified as the ideal working pressure range.

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

[0011] Preferably, several pressure probes are provided on the surface of the air column, which are used to monitor the pressure changes inside the air column in real time.

[0012] Preferably, the air column is inflated by a blower controlled by a PLC system.

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

[0014] Preferably, before suspending the load, the load is calculated based on the air column technical conditions and snow load, and the test load for each suspension point is designed.

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

[0016] Preferably, the analysis method is as follows: plot multiple sets of test data into a line graph and analyze the trend of the change in the height of the middle hanging point from the ground. Based on the linear intersection range of multiple sets of test data, find the ideal working pressure range under the load. 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. The high-pressure heavy-load test, based on the product design technical requirements, is a supplementary test after the ideal working pressure and load test, increasing the pressure and load the product can withstand during normal operation. This test primarily 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) Establish a coordinate system with the span of the inflatable shed as the X-axis, the midpoint of the span as the origin O, the arch height as the Y-axis, and the length of the shed as the Z-axis, and derive the basic equations of the aerodynamic form of the inflatable shed:

[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] Where L is the span width of the shed body, R is the arch radius of the shed body, and Δr is the air column radius;

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

[0027] S K =μ r S0

[0028] Where, μ r S0 is the roof snow distribution coefficient, and S0 is the basic snow pressure.

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

[0030] F X =S K S T

[0031]

[0032] Advantages of this invention:

[0033] 1) Realistically simulate the working state of the air column

[0034] This method simulates the working pressure and load of the air column during operation, which can accurately reflect the working state of the air column and ensure the authenticity, effectiveness and reliability of subsequent tests.

[0035] 2) Quantitative testing and analysis

[0036] The controlled variable method was used to ensure the principle of single variable, and the experimental data were quantitatively tested and recorded. The experimental data were then organized and plotted into line graphs. The trend of the line graphs was observed and analyzed to find the range of linear change.

[0037] 3) Extreme pressure test

[0038] In addition to the working pressure test, an ultimate pressure test is added. The ultimate pressure test verifies the accuracy and reliability of the selected working pressure range.

[0039] 4) Scientific validity of experimental methods

[0040] This experiment employs methods such as controlled variables and quantitative analysis, using real-world data as the basis for the experiment, thereby improving the quality of product performance and providing a scientific and ideal testing method for inflatable products. Attached Figure Description

[0041] Figure 1 This is a schematic diagram of the equipment used in an experimental method to explore the ideal working pressure range of an air column under high pressure and heavy load.

[0042] Figure 2 This is a schematic diagram of the pressure monitoring system.

[0043] Figure 3 This is a schematic diagram of the coordinate system used to calculate the basic equations for the aerodynamics of an inflatable shed.

[0044] Figure 4 This is a schematic diagram of the snow load distribution on an arched structure.

[0045] Figure 5 This is a schematic diagram illustrating the experimental principle.

[0046] In the diagram: 1. Air column; 2. Bow; 3. Pressure gauge; 4. Valve; 5. Fixed constraint module; 6. Load; 7. Pressure gauge; 8. Hook. Detailed Implementation

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

[0048] An experimental method for exploring the ideal working pressure range of an air column under high pressure and heavy load is proposed. The method first uses a fixed constraint module and rigging to fix the air column. Twenty-five hanging points are evenly distributed on the surface of the air column. The air column is inflated to a working pressure of A Pa. A load is then suspended from each hanging point, starting from the center and moving outwards. After the load is fully suspended, the working pressure is gradually increased. The working pressure can be manually set. A PLC system controls the blower for inflation. Data from each test group, including changes in the height of the 13 hanging points, is recorded and analyzed to identify the linear variation range of the hanging points, thus obtaining the ideal working pressure range.

[0049] The air column surface is designed with three pressure gauges, which are redundant to monitor the pressure changes inside the air column in real time. The redundancy design can ensure the accuracy of the monitoring data by comparing each gauge in pairs.

[0050] The proximity switch collects the fan speed and converts the fan speed into a corresponding pulse signal, which is then transmitted to the PLC controller.

[0051] The control box consists of a PLLC control system, a display screen, and an operation panel. The operation panel can be designed with working pressure ranges to meet the needs of setting multiple ranges and large ranges of working pressure. The operation panel can also switch the control system to automatic and manual modes to meet the needs of pressure adjustment during the test process.

[0052] The method specifically includes the following steps:

[0053] 1) Set the test load

[0054] ①Based on the technical conditions of the air column and the snow load, the load was converted and the test load for each hanging point was designed.

[0055] 2) Preset working pressure range

[0056] ① After attaching the specified test load to each hanging point, 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 hook hanging point (out of 25 hook hanging points) from the ground, and collect and analyze the data.

[0057] ② Load Correction Test: Field tests revealed that if the preset working pressure range (①) is inaccurate, significant crushing of the air column occurs at the lower limit of the working pressure range, and insufficient surface stiffness of the air column occurs at the upper limit. In this case, it is necessary to increase the upper and lower limits of the air column working pressure range and repeat test step ① until the ideal working pressure range is found through multiple tests.

[0058] 3) Statistical analysis of experimental data

[0059] The test data from multiple sets were summarized, organized, and analyzed. A line graph was plotted and its trend was analyzed. Based on the linear intersection range of the multiple test data, the ideal working pressure range under the load was determined.

[0060] If the inflatable shelter is to be used in Hebei Province, and investigations indicate that the area may experience gusts of up to level 11, the design should consider the maximum wind speed condition of level 11. The inflatable shelter is intended for use for 5 years and is designed as a temporary structure. According to GB 50009-2012 "Code for Design of Building Structures," considering the characteristics and operating environment of the inflatable shelter, the load calculation mainly involves calculating the snow load.

[0061] Design principles:

[0062] The main pneumatic component of the inflatable shed is the shed body. A 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 of the shed as the Z-axis. A schematic diagram of the coordinate system can be found here. Figure 3 .

[0063] Therefore, the basic equations for the pneumatic mechanism of the inflatable shed are derived, as shown below:

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

[0065] y = Ra (x = 0)

[0066]

[0067] Through repeated iterative calculations, if a is 2813 mm, then R is 12813 mm.

[0068] L – Span width 25000mm

[0069] R – Arch radius 12813mm

[0070] Δr — Air column radius 1000mm

[0071] The 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 inflatable shed projection surface K :

[0075] S K =μ r S0 = 140 N / m 2

[0076] μ r —The snow distribution coefficient on the roof is 0.4, see Figure 4 .

[0077] S0 – Basic snow load 0.35 kN / m 2 Refer to the snow pressure value for Hebei Province that occurs once every 50 years in GB 50009.

[0078] The snow load F on the projected surface of a large inflatable shed X Snow load F on the projected surface of each air column X1 The snow load Fx1 is evenly distributed across 25 hanging points, with each hanging point bearing a load of Fx2.

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

[0080] (As shown in the figure, this is derived from a 60° angle)

[0081]

[0082] Experimental Principle

[0083] The projected dimensions of a single air column in the main structure of the canopy are 40m × 29m, and the projected dimensions of each main air column are 2m × 25m (the angle relative to the ground is relatively large at approximately 2m on both sides, and the snow accumulation is small, so it is not calculated). Figure 5 (As shown). After the snow stopped, on-site staff randomly selected three air columns from the canopy, and then randomly selected three one-square-meter areas above each air column. The snow in these areas was then weighed, the data was recorded, and the average value was calculated. The on-site measurement data was approximately 10 kg / m². 2 Calculations show that the actual maximum snow load of a single air column is approximately 500 kg. The calculation formulas are H = M / S * ρ, F = SK *S, M—Weight of snow; S—Area of ​​snow measured; H—Snowfall depth; S K —Standard value of snow load S K ρ—The density of fresh snow is 0.05~0.10 g / cm³. 3 (Take 0.07 for freshly fallen snow).

[0084] The calculated average snowfall depth H is approximately 15mm; based on the standard snow load value S... K The theoretical maximum snow load is calculated to be approximately 700 kg.

[0085] Example

[0086] This experimental method has been successfully applied to a large inflatable shed in northern China, solving the problem of sheds collapsing due to heavy snow, providing a wider working environment for inflatable products, and improving the quality of inflatable products.

[0087] In this embodiment, the main body of the air column is an arched structure composed of 25 PVC panels, each 2m in diameter, joined together using a heat-sealing process. The inflation / deflation ports, pressure testing nozzles, and blower are all pre-finished components. A bow is attached to the surface of the air column, primarily serving to bear loads and provide structural support. Bottom structural support: The air column is clamped and secured on both the inner and outer sides using structural support modules. The control box consists of a PLC control system, a display screen, and an operation panel. The operation panel allows setting working pressure ranges, accommodating multiple and large working ranges. The operation panel also allows switching the control system between automatic and manual modes to accommodate pressure adjustments during the test.

[0088] In this experiment, the air column was erected approximately 500 meters away from a greenhouse. The surrounding area should be open and unobstructed, and the ground should be hardened and smooth with cement. The erection and operation time of the air column and the greenhouse should be consistent. The experimental procedure is as follows:

[0089] 1) After inflating the air column to the specified pressure, use a crane to erect it.

[0090] 2) Fix the air column inside and outside with a fixed constraint module.

[0091] 3) One end of the ground anchoring rigging is connected to the inner and outer bows on the surface of the air column, and the other end is connected to the ground bolts.

[0092] 4) The control box and 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 the greenhouse in real time.

[0094] Experimental results:

[0095] 1) The air column is loaded with a specified load and operates within the specified pressure range, and the air column is in good condition.

[0096] 2) Based on the temperature and weather conditions in different seasons throughout the year, different working pressure ranges were set, and the working status of the air column and greenhouse was well reported.

[0097] 3) Periodically take a 200×200 mm sample from the surface of the air column and repair it. Measure the remaining strength of the air column material to ensure safe operation of the air column.

[0098] The scope of protection of this invention is not limited to the embodiments described above. Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its scope. If such modifications and variations fall within the scope of the claims of this invention and their equivalents, then the intent of this invention also includes these modifications and variations.

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 several hanging points on its surface, and inflates the air column to bring its working pressure to the lower limit of the preset working pressure range. A load is then suspended at each hanging point. After the load is fully suspended, air is inflated into the air column, gradually increasing the working pressure. After each pressure adjustment, the height of the middle hanging point from the ground is measured and recorded, and analyzed to identify the linear variation range of the middle hanging point, which is the ideal working pressure range. Several pressure gauges are installed on the surface of the air column to monitor the internal pressure changes in real time. The analysis method involves plotting multiple sets of test data into a line graph and analyzing the trend of the height variation of the middle hanging point from the ground. Based on the linear intersection range of multiple sets of test data, the ideal working pressure range under that load is determined. The test data consists of the working pressure and the height of the middle hanging point from the ground at the corresponding working pressure.

2. The experimental method for exploring the ideal working pressure range of a gas column under high pressure and heavy load as described in claim 1, characterized in that, When suspending loads, suspend from the middle outwards to both sides.

3. The experimental method for exploring the ideal working pressure range of a gas column under high pressure and heavy load as described in claim 1, characterized in that, The air column is inflated by a blower controlled by a PLC system.

4. The experimental method for exploring the ideal working pressure range of a gas column under high pressure and heavy load as described in claim 3, characterized in that, The fan speed is collected via a proximity switch and converted into a corresponding pulse signal, which is then transmitted to the PLC controller.

5. The experimental method for exploring the ideal working pressure range of a gas column under high pressure and heavy load as described in claim 1, characterized in that, Before suspending the load, the load is calculated based on the air column technical conditions and snow load, and the test load for each suspension point is designed.

6. The experimental method for exploring the ideal working pressure range of a gas column under high pressure and heavy load as described in claim 5, characterized in that, If the air column shows obvious crushing after a load is suspended on it at the lower limit of the working pressure range, then the upper and lower limits of the working pressure range of the air column should be increased, the load should be resuspended on the air column, and subsequent tests should be conducted until the ideal working pressure range is found.

7. The experimental method for exploring the ideal working pressure range of a gas column under high pressure and heavy load as described in claim 1, characterized in that, After the preset working pressure range test is completed, a high-pressure heavy-load test will be conducted.

8. The experimental method for exploring the ideal working pressure range of a gas column under high pressure and heavy load as described in claim 5, characterized in that, The process of designing the test load for each hanging point includes the following steps: (1) Establish a coordinate system with the span of the inflatable shed as the X-axis, the midpoint of the span as the origin O, the arch height as the Y-axis, and the length of the shed as the Z-axis, and derive the basic equations of the aerodynamic form of the inflatable shed: (2) Calculate the projected area S of the inflatable shed body. T : Where L is the span width of the shed body, and R is the arch radius of the shed body; Where is the radius of the air column; (3) Calculate the standard value S of snow load in the vertical direction of the projection surface of the inflatable shed body. K : in, The snow distribution coefficient on the roof. Basic snow load; (4) The snow load on the projected surface of the inflatable shed is F. X The snow load projected onto the surface of each air column is F. X1 Fx1 is evenly distributed on n hanging points, and the load at each hanging point is Fx2; 。

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