Dynamic Response Test Device and Method of Membrane Structure under Wind-Driven Rain Load

Abstract

The present invention discloses a dynamic response test device and method for a membrane structure under wind-driven rain load. The device includes: a wind chamber; a tensioning assembly disposed in the wind chamber for tensioning the membrane structure to be tested and forming a membrane surface with stable pre-tension; a rainfall assembly located in the wind chamber and disposed above the tensioning assembly; a wind supply assembly disposed at the air inlet of the wind chamber for providing a stable wind field for the wind chamber; a signal acquisition assembly including a laser displacement sensor and an anemometer. The laser displacement sensor is located outside the wind chamber and disposed below the tensioning assembly, and the anemometer is located inside the wind chamber and disposed above the tensioning assembly; a control assembly is communicatively connected to the rainfall assembly, the wind supply assembly, the laser displacement sensor, and the anemometer. The structure of the present invention is simple, reduces the cost of testing the dynamic response of the membrane structure, and is easy to operate. While ensuring high test accuracy, it has strong applicability and can be widely applied to the technical field of building membrane structures.

Description

Technical Field

[0001] The present invention relates to the technical field of building membrane structures, and particularly to a dynamic response test device and method for a membrane structure under wind-driven rain load. Background Art

[0002] As a new type of building structure, membrane structures gradually developed in the mid-20th century. It generates rigidity and finally forms through the prestress on the membrane surface. Due to its excellent architectural features, outstanding structural features and appropriate economy, membrane structures are widely used in large-span space structures such as stadiums, exhibition sites and railway (steam) stations. The development of membrane structures includes the development of membrane materials and the development of structural systems. The development of membrane materials enriches the diversity of structural systems and promotes the generation and application of new structural systems; at the same time, the development of structural systems promotes the development of new membrane materials.

[0003] With the wide application of membrane structures, engineering accidents of membrane structures are not uncommon. Before actual engineering applications, membrane structures will be pre-designed with reference to the only current membrane structure design code in China - "Technical Code for Membrane Structures" (CECS158:2015): When mainly considering the adverse effects of wind loads on membrane structures, other adverse loads such as rain, snow, etc. are also considered concurrently for their negative effects. However, after strict anti-wind design, in actual projects, membrane structures may be severely damaged when the wind speed is far lower than the critical buckling wind speed. Usually, the design of membrane structures only combines various most adverse effects for design without considering the coupling effect under the interaction of adverse loads. And as the main design condition, wind usually accompanies the fall of rain. Therefore, it is necessary to study the dynamic response of membrane structures under the coupled action of wind and rain.

[0004] The existing main methods for studying the coupled action of wind and rain include theoretical analysis, numerical simulation and experimental research. In actual engineering, membrane structures have large spans and heights, and it is almost impossible to replicate the test one-to-one. Usually, the test object is made into a scaled-down model, and then the wind and rain test is carried out in a wind tunnel. However, the cost of a conventional wind tunnel is extremely high, resulting in expensive test costs. Summary of the Invention

[0005] In order to solve the above technical problems, the purpose of the present invention is to provide a low-cost, convenient, fast and highly applicable dynamic response test device and method for a membrane structure under wind-driven rain load.

[0006] The first technical solution adopted by the present invention is:

[0007] A dynamic response test device for a membrane structure under wind-driven rain load, comprising:

[0008] An air chamber, with an air inlet and an air outlet respectively provided on two side surfaces of the air chamber;

[0009] A tensioning assembly, which is arranged in the air chamber and is used to tension the membrane structure to be measured and form a first membrane surface with stable pre-tension;

[0010] A rainfall assembly, which is located in the air chamber and is arranged above the tensioning assembly, and is used to drop raindrops onto the first membrane surface;

[0011] An air supply assembly, which is arranged at the air inlet of the air chamber and is used to provide a stable wind field for the air chamber;

[0012] A signal acquisition assembly, which includes a laser displacement sensor and an anemometer. The laser displacement sensor is located outside the air chamber and is arranged below the tensioning assembly, and the anemometer is located in the air chamber and is arranged above the tensioning assembly;

[0013] A control assembly, and the rainfall assembly, the air supply assembly, the laser displacement sensor and the anemometer are all communicatively connected to the control assembly.

[0014] Further, the tensioning assembly includes a horizontal support part, a vertical support part and a clamping device. The clamping device is used to fix the membrane structure to be measured on the horizontal support part and the vertical support part, so that the membrane structure to be measured forms a first membrane surface with stable pre-tension.

[0015] Further, the rainfall assembly includes a rainfall nozzle and a micro water pump. The rainfall nozzle is arranged above the tensioning assembly, the micro water pump is connected to the rainfall nozzle through a pipeline, and the micro water pump is also communicatively connected to the control assembly.

[0016] Further, at least two through holes are provided on the upper surface of the air chamber. The through holes are located above the tensioning assembly and are used to install the rainfall nozzle and the anemometer.

[0017] Further, the rainfall nozzle is arranged directly above the center point of the tensioning assembly.

[0018] Further, the anemometer is arranged on one side of the rainfall nozzle close to the air inlet of the air chamber.

[0019] Further, the air supply assembly includes a fan and a flow guide cover. The outlet of the fan is communicated with the air inlet of the air chamber through the flow guide cover, and the fan is also communicatively connected to the control assembly.

[0020] Further, the air chamber is an acrylic glass air chamber.

[0021] The second technical solution adopted by the present invention is as follows:

[0022] A control method for a dynamic response test device of a membrane structure under wind-driven rain load. The membrane structure to be tested is fixed on the dynamic response test device of the membrane structure under wind-driven rain load. The membrane structure to be tested is tensioned by a tensioning assembly to form a first membrane surface with stable pre-tension. The dynamic response test method includes the following steps:

[0023] Drop raindrops onto the first membrane surface at a preset rainfall intensity through a rainfall assembly, and provide a stable wind field for the wind chamber through a wind supply assembly;

[0024] Obtain wind speed parameters through an anemometer, and determine a wind speed time history curve according to the wind speed parameters;

[0025] Obtain displacement parameters of the first membrane surface through a laser displacement sensor, and obtain a displacement time history curve according to the displacement parameters;

[0026] Calculate the first dynamic response data of the membrane structure to be tested under wind-driven rain load according to the rainfall intensity, the wind speed time history curve, and the displacement time history curve;

[0027] Obtain the similarity ratio parameter between the membrane structure to be tested and the actual membrane structure, and determine the second dynamic response data of the actual membrane structure under wind-driven rain load according to the first dynamic response data and the similarity ratio parameter.

[0028] Further, the step of calculating the first dynamic response data of the membrane structure to be tested under wind-driven rain load according to the rainfall intensity, the wind speed time history curve, and the displacement time history curve specifically includes:

[0029] Determine the aerodynamic load according to the wind speed time history curve;

[0030] Determine the rain load according to the rainfall intensity and the wind speed time history curve;

[0031] Calculate the first dynamic response data of the membrane structure to be tested under wind-driven rain load according to the aerodynamic load, the rain load, and the displacement time history curve.

[0032] The beneficial effects of the present invention are as follows: A dynamic response test device and method for a membrane structure under wind-driven rain load according to the present invention, during the test, the membrane structure to be tested is tensioned by a tensioning assembly in a wind chamber to form a first membrane surface with stable pre-tension, raindrops are dropped onto the first membrane surface at a preset rainfall intensity through a rainfall assembly above the tensioning assembly, at the same time, a stable wind field is provided for the wind chamber by a wind supply assembly at the air inlet of the wind chamber, then the wind speed parameters in the wind chamber are obtained in real time through an anemometer above the tensioning assembly to obtain a wind speed time history curve, and the displacement parameters of the first membrane surface are obtained in real time through a laser displacement sensor to obtain a displacement time history curve, so as to solve the first dynamic response data of the membrane structure to be tested under wind-driven rain load according to the rainfall intensity, wind speed time history curve and displacement time history curve, and then determine the second dynamic response data of the actual membrane structure under wind-driven rain load according to the similarity ratio parameter between the membrane structure to be tested and the actual membrane structure. The dynamic response test device of the present invention has a simple structure, reduces the cost of dynamic response test of building membrane structures, and is easy to operate; the dynamic response test method of the present invention obtains the displacement time history curve of the membrane structure to be tested under wind-driven rain load, combines the wind speed parameters in the wind chamber and the rainfall intensity to obtain the first dynamic response data of the membrane structure to be tested under wind-driven rain load, and then combines the similarity ratio parameter between the membrane structure to be tested and the actual membrane structure to determine the second dynamic response data of the actual membrane structure under wind-driven rain load, so as to study the dynamic response of building membrane structures under the coupling action of wind and rain, provide a theoretical basis for the wind and rain resistance design of building membrane structures, and have strong applicability while ensuring high test accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 FIG. is a schematic structural diagram of a dynamic response test device for a membrane structure under wind-driven rain load provided by an embodiment of the present invention;

[0034] Figure 2 FIG. is a signal connection diagram of a dynamic response test device for a membrane structure under wind-driven rain load provided by an embodiment of the present invention;

[0035] Figure 3 FIG. is a step flow chart of a dynamic response test method for a membrane structure under wind-driven rain load provided by an embodiment of the present invention.

[0036] REFERENCE SIGNS:

[0037] 10, wind chamber; 101, air inlet; 102, air outlet; 103, through hole; 20, tensioning assembly; 30, rainfall assembly; 301, rainfall nozzle; 302, micro water pump; 40, wind supply assembly; 401, fan; 402, flow guide cover; 50, signal acquisition assembly; 501, laser displacement sensor; 502, anemometer; 60, control assembly; 70, membrane structure to be tested. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0038] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. For the step numbers in the following embodiments, they are only set for the convenience of description and explanation, and no limitation is imposed on the order between the steps. The execution order of each step in the embodiments can be adaptively adjusted according to the understanding of those skilled in the art.

[0039] In the description of the present invention, "a plurality of" means more than two. If the first and second are described, it is only for the purpose of distinguishing technical features and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features or implicitly indicating the sequence of the indicated technical features. In addition, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which this technology belongs. The terms used in the description of this specification are only for describing specific embodiments and are not intended to limit the present invention.

[0040] Referring to Figure 1 and 2 , an embodiment of the present invention provides a dynamic response test device for a membrane structure under wind-driven rain loads, including:

[0041] A wind chamber 10, with an air inlet 101 and an air outlet 102 respectively provided on two sides of the wind chamber 10;

[0042] A tensioning assembly 20, which is arranged in the wind chamber 10 and is used to tension the membrane structure 70 to be tested and form a first membrane surface with a stable pre-tension;

[0043] A rainfall assembly 30, which is located in the wind chamber 10 and is arranged above the tensioning assembly 20, and is used to drop raindrops onto the first membrane surface;

[0044] An air supply assembly 40, which is arranged at the air inlet 101 of the wind chamber 10 and is used to provide a stable wind field for the wind chamber 10;

[0045] A signal acquisition assembly 50, which includes a laser displacement sensor 501 and an anemometer 502. The laser displacement sensor 501 is located outside the wind chamber 10 and is arranged below the tensioning assembly 20, and the anemometer 502 is located inside the wind chamber 10 and is arranged above the tensioning assembly 20;

[0046] A control assembly 60, and the rainfall assembly 30, the air supply assembly 40, the laser displacement sensor 501 and the anemometer 502 are all communicatively connected to the control assembly 60.

[0047] As Figure 1The structural schematic diagram of a dynamic response test device for a membrane structure under wind-driven rain load provided by an embodiment of the present invention is shown as follows. Figure 1 In the figure, the control component 60 is connected to the air supply component 40 and the laser displacement sensor 501 through wires. The control component 60 is wirelessly communicatively connected to the rainfall component 30 ( Figure 1 only the rainfall nozzle 301 is shown) and the anemometer 502. It can be understood that Figure 1 the shown connection manner is only one embodiment of the present invention. The control component 60 and the rainfall component 30, the air supply component 40, the laser displacement sensor 501, and the anemometer 502 can be connected by wired communication or wireless communication.

[0048] As Figure 2 shown, the signal connection diagram of a dynamic response test device for a membrane structure under wind-driven rain load provided by an embodiment of the present invention is shown. The control component 60 is used to issue control instructions to control the rainfall component 30, the air supply component 40, the laser displacement sensor 501, and the anemometer 502, and receive the data collected by the laser displacement sensor 501 and the anemometer 502 for subsequent processing.

[0049] Specifically, in the test of the embodiment of the present invention, the tensile component 20 in the wind chamber 10 is used to tension the membrane structure 70 to be tested to form a first membrane surface with a stable pre-tension. The rainfall component 30 above the tensile component 20 drops raindrops onto the first membrane surface at a preset rainfall intensity. At the same time, the air supply component 40 at the air inlet of the wind chamber 10 provides a stable wind field for the wind chamber 10. Then, the anemometer 502 above the tensile component 20 is used to obtain the wind speed parameters in the wind chamber 10 in real time to obtain the wind speed time history curve, and the laser displacement sensor 501 is used to obtain the displacement parameters of the first membrane surface in real time to obtain the displacement time history curve. Thus, the first dynamic response data of the membrane structure under wind-driven rain load is solved according to the rainfall intensity, the wind speed time history curve, and the displacement time history curve. Furthermore, the second dynamic response data of the actual membrane structure under wind-driven rain load is determined according to the similarity ratio parameter between the membrane structure to be tested and the actual membrane structure. The structure of the embodiment of the present invention is simple, reducing the cost of the dynamic response test of the building membrane structure and being easy to operate; it can study the dynamic response of the building membrane structure under the coupling action of wind and rain, providing a theoretical basis for the wind and rain resistance design of the building membrane structure, and having strong applicability while ensuring high test accuracy.

[0050] Further as an optional implementation manner, the tensile component 20 includes a horizontal support part, a vertical support part, and a clamping device. The clamping device is used to fix the membrane structure 70 to be tested on the horizontal support part and the vertical support part, so that the membrane structure 70 to be tested forms a first membrane surface with a stable pre-tension.

[0051] Specifically, the tensioning assembly 20 is made of a steel skeleton and consists of a horizontal support part and a vertical support part according to the required specifications. The membrane structure 70 to be tested is fixed to the steel skeleton through a clamping device. In the embodiment of the present invention, the wind chamber 10 has an air inlet 101 at the front end and an air outlet 102 at the rear end, so that the wind field in the wind chamber 10 is uniform, stable, and unblocked. The membrane structure 70 to be tested is first fixed to the tensioning assembly 20 through a clamping device, and then the tensioning assembly 20 is fixed in the wind chamber 10, so that the windward side of the membrane structure 70 to be tested faces the air inlet of the wind chamber 10, ensuring that the wind direction on the windward side of the membrane structure is horizontal during the test.

[0052] Further as an optional implementation manner, the rainfall assembly 30 includes a rainfall nozzle 301 and a micro water pump 302. The rainfall nozzle 301 is arranged above the tensioning assembly 20, the micro water pump 302 is connected to the rainfall nozzle 301 through a pipeline, and the micro water pump 302 is also communicatively connected to the control assembly 60.

[0053] Specifically, the micro water pump 302 in the embodiment of the present invention is controlled by the control assembly 60, and raindrops can be dropped from the rainfall nozzle 301 onto the membrane structure 70 to be tested at a preset rainfall intensity.

[0054] Refer to Figure 1 Furthermore, as an optional implementation manner, at least two through holes 103 are provided on the upper surface of the wind chamber 10. The through holes 103 are located above the tensioning assembly 20 and are used for installing the rainfall nozzle 301 and the anemometer 502.

[0055] Specifically, through holes 103 are provided on the upper surface of the wind chamber 10 in the embodiment of the present invention, which facilitates the installation of the probe of the anemometer 502 and the rainfall nozzle 301.

[0056] Refer to Figure 1 Furthermore, as an optional implementation manner, the rainfall nozzle 301 is arranged directly above the center point of the tensioning assembly 20.

[0057] Specifically, in the embodiment of the present invention, placing the rainfall nozzle 301 directly above the center point of the tensioning assembly 20 can ensure uniform rainfall and effective coverage of the entire membrane surface.

[0058] Refer to Figure 1 Furthermore, as an optional implementation manner, the anemometer 502 is arranged on one side of the rainfall nozzle 301 close to the air inlet 101 of the wind chamber 10.

[0059] Specifically, in the embodiment of the present invention, the anemometer probe is arranged between the rainfall nozzle 301 and the air inlet 101, that is, above the windward side of the membrane structure 70 to be tested, and can accurately measure the real-time wind speed of the membrane surface.

[0060] Refer to Figure 1, Further as an optional implementation, the air supply component 40 includes a fan 401 and a fairing 402. The outlet of the fan 401 is communicated with the air inlet 101 of the air chamber 10 through the fairing 402, and the fan 401 is also communicatively connected to the control component 60.

[0061] Specifically, in the embodiment of the present invention, the control component 60 controls the operation of the fan 401. The fan 401 generates air flow by the rotation of the fan blades, and the fairing 402 connects the outlet of the fan 401 with the air inlet 101 of the air chamber 10 to form a sealed and stable wind field, providing the required wind field for subsequent tests.

[0062] Further as an optional implementation, the air chamber 10 is an acrylic air chamber 10.

[0063] Specifically, the main body of the air chamber 10 is made of transparent acrylic, and the entire periphery of the air chamber 10 is transparent, facilitating observation and adjustment during the test process.

[0064] Optionally, the laser displacement sensor 501 is arranged directly below the measuring point on the membrane surface. At the same time, the transparent acrylic effectively separates the two without affecting the positioning of the sensor laser, thereby ensuring that the sensor is not affected by wind and rain during the test, making the measurement data accurate and effective.

[0065] Optionally, the control component 60 is composed of a control switch and a signal processing system. The control switch is connected to the fan 401, the micro water pump 302, the laser displacement sensor 501, and the anemometer 502 through wires or wireless communication to achieve the control of each component. The signal processing system performs relevant processing on the real-time wind speed collected by the anemometer 502 and the membrane surface displacement collected by the laser displacement sensor 501, and calculates the dynamic response data of the building membrane to be measured in combination with the preset rainfall intensity.

[0066] The control component 60 in the embodiment of the present invention integrates each control switch and related signal collection and processing, facilitating the operation, statistics, and adjustment during the test process, greatly improving the test efficiency and avoiding unnecessary increase in personnel, time, and cost losses.

[0067] Optionally, the tensioning component 20 in the embodiment of the present invention is fabricated by welding a steel skeleton. The material is selected as smooth ribless steel bars, and the size can be reduced in proportion according to the actual model membrane surface boundary support. During fabrication, attention should be paid to the spatial relationship of the skeleton to avoid the clamping device being unable to fix the membrane surface when tensioning the membrane. After fabrication, the surface and joints of the skeleton need to be polished to make them smooth without sharp protrusions to avoid damaging the membrane surface.

[0068] Optionally, to ensure the accuracy of the test results, the cross-sectional area of the building membrane structure model in the wind chamber 10 should not be too large and should be controlled within the test accuracy range. Therefore, it is necessary to pre-estimate the size of the wind chamber 10 after reducing the model size proportionally. After determining the length, width, and height of the wind chamber 10, calculate the ratio of the windward area of the model to the cross-sectional size of the wind chamber 10 and adjust it to the required value. Then, design the position of the reserved holes to facilitate the fixation of the probe of the anemometer 502 and the probe of the artificial rainfall simulation device during the later test.

[0069] Optionally, in the embodiment of the present invention, the to-be-tested membrane structure 70 is cut according to the size requirements, and four points A, B, C, and D to be tested are marked. The four tension edges of the membrane surface are fixed through a clamping device and installed on the prefabricated tension assembly 20, and the tension assembly 20 is fixed in the wind chamber 10 using a hot melt glue gun; the laser head of the laser displacement sensor 501 is placed below the membrane surface, so that the laser emitted by the laser head is directly aimed at the four pre-marked points A, B, C, and D.

[0070] It can be realized that most of the well-known wind tunnel laboratories in China are currently manufactured by aerospace colleges, with construction costs as high as several million or even tens of millions, high site requirements, and long construction periods, mostly two to five years. To conduct tests in the built wind tunnel tests, reservations are required, the basic operating principles of the wind tunnel need to be learned, relevant precautions need to be understood, and certain test fees need to be paid.

[0071] When particularly high test data accuracy is not required or only the general laws of the building membrane structure under wind-driven rain loads need to be understood, conducting tests in a wind tunnel laboratory will cause excessive waste of time and funds. The dynamic response test device of the embodiment of the present invention can be manufactured according to requirements, with low manufacturing costs and short manufacturing cycles. At the same time, the test site is not greatly restricted, greatly saving various costs. Correspondingly, the great savings in various costs enable the device to significantly lower the threshold for conducting tests, and both the test model and the device can be used repeatedly, greatly avoiding waste.

[0072] The above is an explanation of the structure of the dynamic response test device of the embodiment of the present invention. Next, the dynamic response test method of the embodiment of the present invention will be explained.

[0073] Refer to Figure 3 , the embodiment of the present invention provides a dynamic response test method for a membrane structure under wind-driven rain loads. The to-be-tested membrane structure 70 is fixed on the above-mentioned dynamic response test device for a membrane structure under wind-driven rain loads. The to-be-tested membrane structure 70 is tensioned through the tension assembly 20 to form a first membrane surface with a stable pre-tension. The dynamic response test method includes the following steps:

[0074] S101. Drop raindrops onto the first membrane surface through the rainfall component 30 at a preset rainfall intensity, and provide a stable wind field for the wind chamber 10 through the air supply component 40;

[0075] S102. Obtain the wind speed parameter through the anemometer 502, and determine the wind speed time history curve according to the wind speed parameter;

[0076] S103. Obtain the displacement parameter of the first membrane surface through the laser displacement sensor 501, and obtain the displacement time history curve according to the displacement parameter;

[0077] S104. Calculate the first dynamic response data of the membrane structure 70 to be tested under the action of wind-driven rain load according to the rainfall intensity, the wind speed time history curve, and the displacement time history curve;

[0078] S105. Obtain the similarity ratio parameter between the membrane structure to be tested and the actual membrane structure, and determine the second dynamic response data of the actual membrane structure under the action of wind-driven rain load according to the first dynamic response data and the similarity ratio parameter.

[0079] Specifically, the research on the dynamic response of the building membrane structure under the action of wind-driven rain load in the embodiment of the present invention is based on the actual project. Its basic principle is: fabricate a geometrically similar reduced model of the actual membrane structure (i.e., the membrane structure 70 to be tested), place it in the geometrically similar reduced wind chamber 10 that is pre-designed and fabricated and fix it. The rainfall component 30 and the anemometer 502 are connected to the top of the wind chamber 10. At the same time, the air supply component 40 is connected to the air inlet 101 of the wind tunnel, and the control of the rainfall component 30 and the air supply component 40 is realized through the control component 60. Before the test starts, the rainfall intensity required for the test process is preset in advance through the control component 60. During the test process, the real-time wind speed during the test can be obtained by the anemometer 502 and the wind speed time history curve can be exported. At the same time, the displacement of the building membrane surface is measured by the non-contact laser displacement sensor 501 placed directly below the membrane surface and its displacement time history curve is exported. Then, the dynamic response data such as the displacement, amplitude, and speed of the membrane structure 70 to be tested under the wind-driven rain load are calculated. Furthermore, the dynamic response data of the actual membrane structure are obtained by combining the similarity ratio parameter between the actual membrane structure and the membrane structure to be tested.

[0080] The basic principle and calculation process of the embodiment of the present invention are deduced and described below. The theoretical structural model of the membrane structure to be tested in the embodiment of the present invention is a steel skeleton supported membrane structure. The membrane material is an elastic material, simply supported on four sides, and its two main fiber directions in the orthogonal directions x and y have different Young's moduli; a and b respectively represent the lengths of the membrane in the x and y directions; N ox and N oy respectively represent the pre-tensions in the x and y directions; f1 and f2 are the mid-span arches on the y and x axes respectively; the theoretical derivation is based on the large deflection theory of thin films and the law of conservation of momentum.

[0081] Based on von Karman's large deflection theory and D'Alembert's principle, the dynamic motion equation (1) and compatibility equation (2) of the skeleton-supported membrane are obtained as follows:

[0082]

[0083] In the above equations, ρ0 represents the areal density of the membrane material; c represents the viscous damping coefficient; N x and N y are the stress increments in the x and y directions respectively; N 0x and N 0y represent the pre-tensions in the x and y directions respectively; N xy represents the shear force; w represents the displacement function w(x, y, t); h represents the thickness of the membrane material; E1 and E2 are the Young's elastic moduli in the x and y directions respectively; G represents the shear modulus; k 0x represents the initial principal curvature in the x direction; μ1 and μ2 are the Poisson's ratios in the x and y directions; P W represents the aerodynamic load, and P R represents the rain load.

[0084] The dynamic motion equation (1) and compatibility equation (2) together constitute the governing equations of the skeleton-supported membrane structure under wind-driven rain loads.

[0085] The corresponding displacement boundary conditions (3) and stress boundary conditions (4) for simply supported edges on all four sides are as follows:

[0086]

[0087] Assuming that the displacement boundary conditions (3) and stress boundary conditions (4) are satisfied, simplifying and solving equations (1) and (2) respectively gives the following equations (5) and (6):

[0088]

[0089] In the above equations, W is the given mode function, T(t) is a function of time; m and n are the numbers of sine half-waves in the x and y directions respectively, and are positive integers.

[0090]

[0091] Applying the Galerkin method to transform equation (6) into the following equation (7):

[0092]

[0093] Then, transforming equation (7) into a differential equation (8) as follows:

[0094] A0T″(t)+B0T′(t)+C0T(t)+D0T 2 (t)+E0T3 P(t) = P0 (8)

[0095] Among them, the expressions of some parameters are as follows:

[0096]

[0097] The expression of aerodynamic load is:

[0098] P W = -γ1T″ - γ2VT′ - γ3V 2 T - γ4V 2 (9)

[0099] Among them, the expressions of some parameters are as follows:

[0100]

[0101] In the above formula, ξ and η represent the position coordinates when the air flow is along the arch direction of the membrane surface, The integration region S ∈ {0 ≤ ξ ≤ a, 0 ≤ η ≤ b}, ρ a is the gas density, w is the displacement function of the membrane surface, and z0 is the surface function of the membrane surface.

[0102] The expression of rain load is:

[0103] P R = γ5V(t) 2 + γ5·γ6 (10)

[0104] Among them, the expressions of some parameters are as follows:

[0105]

[0106] In the above formula, ρ w is the density of water (generally taken as ρ w = 1.0×10 3 kg·m -3 ), ρ a is the density of air (generally taken as ρ a = 1.293kg·m -3 ), η is the viscosity coefficient of air (generally taken as η = 17.1×10 -6 kg·m -1 ·s -1 ), V is determined according to the wind speed of different wind speed levels, and the rainfall intensity I can be preset.

[0107] Substitute equations (9) and (10) into equation (8), and through simplified calculation, the differential equation of membrane surface vibration can be obtained as:

[0108] T″(t) + λ1T′(t) + λ2T(t) + λ3T2 (t) + λ4T 3 (t) = λ5T′(t)V(t) + λ6T(t)V(t) 2 + λ7V(t) 2 + λ8 (11)

[0109] Among them, the expressions of some parameters are as follows:

[0110]

[0111] Then, the fourth-order Runge-Kutta method is used to solve the differential equation (11). By solving the differential equation (11), the dynamic response data such as displacement, amplitude, and velocity of the steel skeleton supported membrane structure under wind-driven rain load can be obtained.

[0112] When designing the aerodynamic elasticity and wind-driven rain model of the membrane structure of the membrane surface, considering that the thin film structure belongs to a flexible structure with a low vibration frequency, and the prototype test requires a long period and high cost, therefore, in the embodiments of the present invention, according to the similarity theory, the membrane structure to be measured is used to replace the actual membrane structure test. Finally, when converting to the dynamic response data of the actual membrane structure, it is necessary to calculate in combination with the similarity ratio of the corresponding parameters. In the embodiments of the present invention, the density similarity ratio λ ρ is taken as 1, and the other similarity theories adopted are as follows:

[0113] 1) Geometric similarity means the similarity of the geometric shapes between the test model and the physical prototype, that is:

[0114]

[0115] Among them, L m represents the geometric length of the membrane structure to be measured, and L p represents the geometric length of the actual membrane structure. In the embodiments of the present invention, the geometric similarity ratio λ L = 1 / 20 is selected according to the common membrane material sizes in actual engineering.

[0116] 2) Froude number similarity means the square root of the ratio of inertial force to gravity, that is:

[0117]

[0118] Among them, F r represents the Froude number, ρ represents the density of the object, V represents the moving speed of the object, g represents the acceleration due to gravity, and L is the characteristic length of the object. In the embodiments of the present invention, the Froude numbers of the membrane structure to be measured and the actual membrane structure are the same.

[0119] The volume similarity ratio is:

[0120]

[0121] Among them, λ L represents the volume similarity ratio.

[0122] 3) Euler number similarity means that the ratio of the pressure acting on the object surface to the inertial force, that is:

[0123]

[0124] Among them, P represents the pressure acting on the object surface, represents the Euler number of the membrane structure to be measured, represents the Euler number of the actual membrane structure. In the embodiments of the present invention, the Euler numbers of the membrane structure to be measured and the actual membrane structure are the same.

[0125] The pressure similarity ratio is:

[0126] λ p = λ L (16)

[0127] Among them, λ P represents the pressure similarity ratio.

[0128] 4) Tesla number similarity means that the ratio of the unsteady motion inertial force to the inertial force, that is:

[0129]

[0130] Among them, S r represents the Tesla number. In the embodiments of the present invention, the Tesla numbers of the membrane structure to be measured and the actual membrane structure are the same.

[0131] The time scale ratio λ T is:

[0132]

[0133] The frequency scale ratio λ ω is:

[0134]

[0135] 5) Elastic parameter similarity:

[0136]

[0137] Among them, represents the elastic parameter similarity ratio between the membrane structure to be measured and the actual membrane structure.

[0138] 6) Initial pre-tension number similarity:

[0139] λ N = λ L 2 (21)

[0140] Among them, λ N represents the similarity ratio of the initial pre-tension number between the membrane structure to be measured and the actual membrane structure.

[0141] 7) Similarity in mass number:

[0142]

[0143] Among them, λ M represents the similarity ratio of the mass number between the membrane structure to be measured and the actual membrane structure.

[0144] 8) Similarity in displacement number:

[0145] λ w = λ L (23)

[0146] Among them, λ w represents the similarity ratio of the displacement number between the membrane structure to be measured and the actual membrane structure

[0147] 9) Similarity ratio of rainfall intensity:

[0148]

[0149] Among them, λ w represents the similarity ratio of the rainfall intensity between the membrane structure to be measured and the actual membrane structure.

[0150] The above introduces the various similarity ratio parameters of the membrane structure to be measured and the actual membrane structure in the embodiments of the present invention. According to these similarity ratio parameters and the obtained first dynamic response data, the second dynamic response data of the actual membrane structure under the action of wind-driven rain load can be obtained.

[0151] Further as an optional implementation manner, the step S104 of calculating the first dynamic response data of the membrane structure 70 to be measured under the action of wind-driven rain load according to the rainfall intensity, the wind speed time history curve, and the displacement time history curve specifically includes:

[0152] S1041. Determine the aerodynamic load according to the wind speed time history curve;

[0153] S1042. Determine the rain load according to the rainfall intensity and the wind speed time history curve;

[0154] S1043. Calculate the first dynamic response data of the membrane structure 70 to be measured under the action of wind-driven rain load according to the aerodynamic load, the rain load, and the displacement time history curve.

[0155] Specifically, the expressions of aerodynamic load and rain load have been described in the foregoing content. The aerodynamic load and rain load can be determined according to the wind speed time history curve and rainfall intensity, and then the dynamic response data of the membrane structure to be measured under the action of wind-driven rain load can be solved. Finally, combined with the similarity criteria described above, the dynamic response data of the membrane structure in the actual project can be converted.

[0156] The embodiment of the present invention provides a device and method for measuring the dynamic response of a building membrane structure under wind-driven rain, which are relatively economical, convenient and fast, and have strong applicability. Compared with the prior art, the embodiment of the present invention has the following advantages:

[0157] 1) The structure of the test device is simple, the manufacturing cost of the device is low, the requirements for the test site are not high, and the required power device is simple and stable. The cost of a conventional low-speed test wind tunnel is as high as several million yuan, the construction site requirements are high, and the construction period is long. Conducting a complete test in an existing wind tunnel often costs tens of thousands of yuan. However, the present invention can make a testable device at a lower cost, greatly saving the test funds.

[0158] 2) The test method is simple, does not require too much theoretical basis and does not need to learn too many extra operations. The number of personnel involved in the test process is small, avoiding waste of resources.

[0159] 3) The measurement device has high measurement accuracy, can better reflect the objective law of building membrane materials in actual projects, and does not need to directly contact the membrane materials during the measurement process, which can effectively protect the test equipment, so as to achieve the purpose of multiple and repeated use.

[0160] It should be recognized that the embodiments of the present invention can be implemented or carried out by computer hardware, a combination of hardware and software, or by computer instructions stored in a non-transitory computer-readable memory. The above method can be implemented in a computer program using standard programming techniques - including a non-transitory computer-readable storage medium configured with the computer program, wherein the storage medium so configured causes the computer to operate in a specific and predefined manner - according to the methods and drawings described in the specific embodiments. Each program can be implemented in a high-level procedural or object-oriented programming language to communicate with the computer system. However, if necessary, the program can be implemented in assembly or machine language. In any case, the language can be a compiled or interpreted language. In addition, for this purpose, the program can run on a dedicated integrated circuit programmed for this purpose.

[0161] In addition, the operations of the processes described herein may be performed in any suitable order, unless otherwise indicated herein or otherwise clearly contradicted by the context. The processes described herein (or variations and / or combinations thereof) may be performed under the control of one or more computer systems configured with executable instructions and may be implemented as code (e.g., executable instructions, one or more computer programs, or one or more applications) collectively executed on one or more processors, by hardware, or by a combination thereof. The above computer programs include a plurality of instructions executable by one or more processors.

[0162] Further, the above method can be implemented in any type of computing platform operably connected to a suitable one, including but not limited to personal computers, minicomputers, mainframes, workstations, network or distributed computing environments, separate or integrated computer platforms, or communicating with charged particle tools or other imaging devices, etc. Aspects of the present invention can be implemented in machine-readable code stored on a non-transitory storage medium or device, whether removable or integrated into the computing platform, such as a hard disk, optical read and / or write storage medium, RAM, ROM, etc., such that it can be read by a programmable computer and, when the storage medium or device is read by the computer, can be used to configure and operate the computer to perform the processes described herein. In addition, the machine-readable code, or portions thereof, can be transmitted via a wired or wireless network. When such media include instructions or programs that implement the steps described above in conjunction with a microprocessor or other data processor, the inventions described herein include these and other different types of non-transitory computer-readable storage media. When programmed according to the methods and techniques described in the present invention, the present invention also includes the computer itself.

[0163] The computer program is capable of being applied to input data to perform the functions described herein, thereby transforming the input data to generate output data stored in non-volatile memory. The output information can also be applied to one or more output devices such as a display. In a preferred embodiment of the present invention, the transformed data represents physical and tangible objects, including a specific visual depiction of the physical and tangible objects generated on the display.

[0164] As described above, these are only the preferred embodiments of the present invention. The present invention is not limited to the above-described embodiments. As long as the same means are used to achieve the technical effects of the present invention, any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention. Within the scope of protection of the present invention, its technical solutions and / or implementation manners can have various different modifications and variations.

Claims

1. A dynamic response test device for a membrane structure under wind-driven rain load, characterized in that Comprising: An air chamber, with an air inlet and an air outlet respectively provided on two sides of the air chamber; A tensioning assembly, which is arranged in the air chamber and is used to tension the membrane structure to be tested and form a first membrane surface with stable pre-tension; A rainfall assembly, which is located in the air chamber and is arranged above the tensioning assembly, and is used to drop raindrops onto the first membrane surface; An air supply assembly, which is arranged at the air inlet of the air chamber and is used to provide a stable wind field for the air chamber; A signal acquisition assembly, which includes a laser displacement sensor and an anemometer. The laser displacement sensor is located outside the air chamber and is arranged below the tensioning assembly, and the anemometer is located inside the air chamber and is arranged above the tensioning assembly; A control assembly, and the rainfall assembly, the air supply assembly, the laser displacement sensor and the anemometer are all communicatively connected to the control assembly; Wherein, the control assembly is used to obtain wind speed parameters through the anemometer, determine the wind speed time history curve according to the wind speed parameters, obtain the displacement parameters of the first membrane surface through the laser displacement sensor, obtain the displacement time history curve according to the displacement parameters, calculate and obtain the first dynamic response data of the membrane structure to be tested under the action of wind-driven rain load according to the rainfall intensity, the wind speed time history curve and the displacement time history curve, obtain the similarity ratio parameter between the membrane structure to be tested and the actual membrane structure, and determine the second dynamic response data of the actual membrane structure under the action of wind-driven rain load according to the first dynamic response data and the similarity ratio parameter.

2. The dynamic response test device for a membrane structure under wind-driven rain load according to claim 1, characterized in that: The tensioning assembly includes a horizontal support part, a vertical support part and a clamping device. The clamping device is used to fix the membrane structure to be tested on the horizontal support part and the vertical support part, so that the membrane structure to be tested forms a first membrane surface with stable pre-tension.

3. The dynamic response test device for a membrane structure under wind-driven rain load according to claim 1, characterized in that: The rainfall assembly includes a rainfall nozzle and a micro water pump. The rainfall nozzle is arranged above the tensioning assembly, the micro water pump is connected to the rainfall nozzle through a pipeline, and the micro water pump is also communicatively connected to the control assembly.

4. The dynamic response test device for a membrane structure under wind-driven rain load according to claim 3, characterized in that: At least two through holes are provided on the upper surface of the air chamber, and the through holes are located above the tensioning assembly and are used to install the rainfall nozzle and the anemometer.

5. The dynamic response test device for a membrane structure under wind-driven rain load according to claim 3, characterized in that: The rainfall nozzle is arranged directly above the center point of the tensioning assembly.

6. The dynamic response test device for a membrane structure under wind-driven rain load according to claim 5, characterized in that: The anemometer is arranged on one side of the rainfall nozzle close to the air inlet of the air chamber.

7. The dynamic response test device for a membrane structure under wind-driven rain load according to claim 1, characterized in that: The air supply assembly includes a fan and a flow guide cover. The outlet of the fan is communicated with the air inlet of the air chamber through the flow guide cover, and the fan is also communicatively connected to the control assembly.

8. The dynamic response test device for a membrane structure under wind-driven rain load according to any one of claims 1 to 7, characterized in that : The air chamber is an acrylic air chamber.

9. A dynamic response test method for a membrane structure under wind-driven rain load, characterized in that, The membrane structure to be tested is fixed on the dynamic response test device of the membrane structure according to any one of claims 1 to 8 under the action of wind-driven rain load. The membrane structure to be tested is tensioned by the tensioning assembly to form a first membrane surface with stable pre-tension. The dynamic response test method includes the following steps: Drop raindrops onto the first membrane surface through the rainfall assembly at a preset rainfall intensity, and provide a stable wind field for the air chamber through the air supply assembly; Obtain the wind speed parameter through an anemometer, and determine the wind speed time history curve according to the wind speed parameter; Obtain the displacement parameter of the first membrane surface through a laser displacement sensor, and obtain the displacement time history curve according to the displacement parameter; Calculate the first dynamic response data of the membrane structure to be measured under the action of wind-driven rain load according to the rainfall intensity, the wind speed time history curve, and the displacement time history curve; Obtain the similarity ratio parameter between the membrane structure to be measured and the actual membrane structure, and determine the second dynamic response data of the actual membrane structure under the action of wind-driven rain load according to the first dynamic response data and the similarity ratio parameter.

10. The dynamic response test method according to claim 9, characterized in that, The step of calculating the first dynamic response data of the membrane structure to be measured under the action of wind-driven rain load according to the rainfall intensity, the wind speed time history curve, and the displacement time history curve specifically includes: Determine the aerodynamic load according to the wind speed time history curve; Determine the rain load according to the rainfall intensity and the wind speed time history curve; Calculate the first dynamic response data of the membrane structure to be measured under the action of wind-driven rain load according to the aerodynamic load, the rain load, and the displacement time history curve.

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