A displacement calculation method for polycarbonate U-shaped hollow plate

Abstract

A method for calculating the displacement of a polycarbonate U-shaped hollow plate, comprising the steps of measuring and determining the basic parameters of the U-shaped hollow plate; determining the equivalent thickness t of the plate; eq ; Determine the bending stiffness D of the plate; Determine the displacement reduction coefficient η; Determine the adjustment coefficient γ; Determine the mid-span vertical displacement ω of the U-shaped hollow plate according to the vertical displacement formula. In the mid-span vertical displacement ω formula, μ is the flexural coefficient, q is the load on the plate, and a is the width of the plate in the size parameter. The present invention provides a displacement calculation formula for a polycarbonate U-shaped hollow flat plate and the determination of related parameters in the formula. The displacement calculation formula for the U-shaped hollow plate is based on the small displacement calculation theory of the plate, and the values ​​of basic parameters, equivalent thickness, bending stiffness, coefficient parameters, displacement reduction coefficient, adjustment coefficient and other parameters are determined in turn according to the results of experiments and finite element calculations, and finally the vertical displacement calculation formula for the U-shaped hollow plate is obtained, filling the gap in the displacement calculation theory of the U-shaped hollow plate.

Description

Technical Field

[0001] The present invention belongs to the field of displacement calculation of polycarbonate hollow plates, and particularly relates to a method for calculating the displacement of a polycarbonate U-shaped hollow plate. Background Art

[0002] As a new material, polycarbonate has excellent properties such as light weight, high strength, high light transmittance, heat preservation and heat insulation. At the same time, solid plates and hollow plates made of polycarbonate materials are increasingly used in the roofing systems of important public buildings such as stadiums, airports, and high-speed railway stations. Polycarbonate hollow plates are divided into multi-layer orifice cavities, multi-layer X-shaped cavities, multi-layer V-shaped cavities, etc. according to the cavities, and are divided into hollow flat plates, arc hollow plates, etc. according to the shape. According to the span of the hollow plate, the common number of layers is generally 2-7 layers, and the thickness is 4mm-30mm.

[0003] The U-shaped hollow plate is mechanically connected at the support position, which is convenient for construction and has better waterproof performance; the U-shaped hollow plate has multiple cavities, and has more excellent vertical stiffness and heat preservation and heat insulation performance. Therefore, the U-shaped hollow plate is widely used in actual projects.

[0004] When polycarbonate is applied to U-shaped hollow plates, the elastic modulus of the material is low, only 1 / 30 of that of glass materials. Therefore, when the U-shaped hollow plate is used as a component of the roofing system, deformation mainly plays a controlling role. When the U-shaped hollow plate fails, the material foundation is in an elastic state.

[0005] At present, there is no displacement calculation formula for U-shaped hollow plates in the publicly available technologies, and the research results on the deformation performance of U-shaped hollow plates are lacking. The standard provisions lack detailed regulations on its displacement calculation formula. In actual projects, it is mainly based on engineering experience to match the specifications, models and thicknesses of U-shaped hollow plates according to the span. In case of special situations, such as snow load or wind load exceeding the conventional experience values, engineering experience is not referenceable and safe.

[0006] At the same time, in the existing publicly available technologies, the thin plate displacement calculation formula ⑤ is derived under small displacement conditions. It assumes that the plate is only subjected to bending, only has bending stress and the in-plane membrane stress is ignored. The applicable range is mainly ω < t, where ω is the maximum displacement of the plate and t is the plate thickness, that is, the plate height. When ω > t, the formula ⑤ calculation produces significant errors, that is, the calculated displacement is larger than the actual one, and as the ratio of displacement to plate thickness ω / t increases, the calculated displacement is too large to be acceptable, losing the significance of calculation and engineering significance.

[0007]

[0008] In the formula: μ is the deflection coefficient, υ is the Poisson's ratio, q is the uniform load on the plate surface, a is the width of the plate, E is the elastic modulus of the plate, and D is the bending stiffness of the plate.

[0009] Since there is no displacement calculation formula for U-shaped hollow plates in the currently disclosed technologies, in the case of U-shaped hollow plates with multiple cavities, the applicable range of formula ⑤ is ω < t. If the total height of the plate is taken as t in the bending stiffness D formula ④ of the plate and only formula ⑤ is used to calculate the displacement, the result will be seriously distorted.

[0010] Therefore, there is an urgent need for a displacement calculation method for polycarbonate U-shaped hollow plates that is compatible with the actual stress. Summary of the Invention

[0011] The object of the present invention is to provide a displacement calculation method for polycarbonate U-shaped hollow plates, to solve the technical problem that the displacement calculated by only using the thin plate displacement calculation formula for U-shaped hollow plates will be seriously distorted; and to solve the technical problem that according to engineering experience, the specifications, models and thicknesses of U-shaped hollow plates are matched according to the span. In case of special situations exceeding the conventional experience values, the existing engineering experience is not referenceable and safe.

[0012] To achieve the above object, the present invention adopts the following technical solutions:

[0013] A displacement calculation method for polycarbonate U-shaped hollow plates is as follows:

[0014] Step 1, measure and determine the basic parameters of the U-shaped hollow plate,

[0015] The basic parameters include dimensional parameters, plate type, form of support connection points, load on the plate body, and load application direction;

[0016] Step 2, determine the equivalent thickness t of the plate according to the dimensional parameters in the basic parameters of Step 1 eq ;

[0017] The cross-section of the U-shaped hollow plate is a cavity with an opening and a void truss structure, and the equivalent thickness t is obtained eq related to the dimensions of the upper and lower surface layers;

[0018] Step 3, determine the bending stiffness D of the plate according to the equivalent thickness t of the plate obtained in Step 2 eq， ;

[0019] Step 4, determine the displacement reduction coefficient η,

[0020] The displacement reduction coefficient η is a parameter directly related to the displacement;

[0021] Introduce the coefficient parameter θ to convert the displacement reduction coefficient η into a physical parameter related to the dimensional parameters in the basic parameters and the load on the plate body,

[0022] The calculation formula of the displacement reduction coefficient η is fitted into a power function formula related to the coefficient parameter θ, and the value range of the displacement reduction coefficient η is obtained;

[0023] Step 5: Determine the adjustment coefficient γ, and determine the range of the adjustment coefficient according to the load direction in the basic parameters of step 1; Step 6: Obtain and calculate the mid-span vertical displacement ω of the U-shaped hollow plate according to formula ①:

[0024]

[0025] Where μ is the deflection coefficient, q is the load on the plate, and a is the width of the plate in the dimensional parameters.

[0026] The basic parameters in step 1 include:

[0027] Dimensional parameters: board width a, board height h, upper surface thickness t 1 , thickness of lower surface layer t 2 The height h from the plate centroid to the lower surface layer 1 ;

[0028] The form of plate type and support connection point: a one-way plate with fixed hinge supports on opposite sides is used to determine the form of the calculation model;

[0029] The load q on the plate is equivalent to the uniformly distributed load on the plate surface;

[0030] Load action direction: There are two forms: load action direction upward or load action direction downward, and the corresponding value of the adjustment coefficient γ has two ranges.

[0031] In step 2, the equivalent thickness of the plate is eq The calculation formula is as follows:

[0032] First determine h 1 :

[0033]

[0034] Then the h obtained in formula ② is 1 Substituting into formula ③, we get the equivalent thickness t eq :

[0035]

[0036] Where, t 1 is the thickness of the upper surface layer, t 2 is the thickness of the lower surface layer, h is the height of the plate, h 1 It is the height of the plate centroid from the lower surface layer.

[0037] In step 3, the calculation formula of the bending stiffness D of the plate is as follows:

[0038]

[0039] Where D is the bending stiffness of the plate, E is the elastic modulus of the plate, and t is the equivalent thickness t eq , υ is Poisson's ratio.

[0040] In step 4, the displacement reduction factor η is considered to be directly related to the displacement ω / t eq is the parameter;

[0041] According to the calculation formula ④ of the bending stiffness D of the plate and the calculation formula ⑤ of the displacement of the plate, ω / t eq Converted into physical parameters related to the basic parameters of the board, the proportional conversion process is shown in formula ⑥:

[0042]

[0043] Where: ω is the vertical displacement of the plate, μ is the flexure coefficient, υ is the Poisson's ratio, q is the load on the plate, a is the width of the plate, E is the elastic modulus of the plate, D is the bending stiffness of the plate, t eq is the equivalent thickness of the plate; Formula ⑥ is based on ω and Proportional to D is proportional, so and is proportional to; the displacement reduction coefficient η is converted into relationship curve.

[0044] In step 4, the coefficient parameter θ is introduced.

[0045]

[0046] In the formula, q is the load on the plate, a is the width of the plate, E is the elastic modulus of the plate, and t eq is the equivalent thickness of the plate;

[0047] The calculation formula of displacement reduction coefficient η is as follows:

[0048]

[0049] In the formula, ω 1 The maximum mid-span displacement calculated by the plate displacement calculation formula ⑤;

[0050] ω 2 In order to consider the form of plate type and support connection point in the foundation parameters, a one-way plate model with fixed hinge supports on opposite sides is established, and the maximum mid-span displacement of the finite element calculation is considered considering large deformation geometric nonlinearity;

[0051] A scatter plot is established based on the data of η and θ, and the calculation formula of the displacement reduction coefficient η using power function fitting is as follows:

[0052] η=0.7e (-θ / 30) +0.3 ⑨;

[0053] The value range of η is 0.3~1.0.

[0054] In step 5, the calculation formula of the adjustment coefficient γ is as follows:

[0055]

[0056] In the formula, ω 2 In order to consider the form of plate type and support connection point in the foundation parameters, a one-way plate model with fixed hinge supports on opposite sides is established, and the maximum mid-span displacement of the finite element calculation is considered considering large deformation geometric nonlinearity;

[0057] ω 3 is the maximum mid-span displacement in the actual test comparison results.

[0058] When the load acts downward, the value range of γ is [1.1~1.3],

[0059] When the load acts upward, the value range of γ is [1.3~1.5].

[0060] Preferably, when the load acts downward, γ takes the value of 1.1;

[0061] Preferably, when the load acts upward, γ takes a value of 1.5.

[0062] Compared with the prior art, the present invention has the following characteristics and beneficial effects:

[0063] The present invention proposes a vertical displacement calculation formula for a U-shaped hollow plate based on theoretical formulas, test data and engineering experience. The present invention provides a displacement calculation formula for a polycarbonate U-shaped hollow flat plate and the determination of relevant parameters in the formula. The displacement calculation formula for the U-shaped hollow plate is based on the small displacement calculation theory of the plate, and the values ​​of basic parameters, equivalent thickness, bending stiffness, coefficient parameters, displacement reduction coefficient, adjustment coefficient and other parameters are determined in sequence according to the test and finite element calculation results, and finally the vertical displacement calculation formula for the U-shaped hollow plate is obtained, filling the gap in the displacement calculation theory of the U-shaped hollow plate. BRIEF DESCRIPTION OF THE DRAWINGS

[0064] The present invention will be further described in detail below in conjunction with the accompanying drawings.

[0065] Figure 1 It is a structural schematic diagram of the plane layout of the U-shaped hollow plate and the support connection points of the present invention.

[0066] Figure 2 It is a schematic diagram of the half-span cross-section structure of a U-shaped hollow plate.

[0067] Figure 3 It is the mid-span deformation diagram of the U-shaped hollow plate.

[0068] Figure 4 It is the schematic diagram of the cross-section parameters of the U-shaped hollow plate.

[0069] Figure 5 It is the fitting formula diagram of η and θ.

[0070] Figure 6 It is the comparison result when the load acts upward.

[0071] Figure 7 It is the comparison result when the load acts downward.

[0072] Figure 8 It is the comparison result between the calculation result of the formula of the present invention and the test value.

[0073] Reference signs: 1 - support connection point, 2 - vertical rib, 3 - upper surface layer, 4 - lower surface layer, 5 - intermediate layer. Detailed implementation manners

[0074] For the embodiments, see Figure 1 As shown, the present invention mainly takes the U-shaped hollow plate as the research object. The U-shaped hollow plate is a kind of hollow plate. See Figure 1 As shown, it means that vertical support connection points 1 protruding from the plane of the flat plate are provided at both edges of the hollow flat plate, with a length of L and a width of a. The cross-section of the U-shaped hollow is shown in Figure 2 As shown. For the U-shaped hollow plate, due to the existence of multiple cavities, the applicable range of formula ⑤ is ω < t. Here, t should not be the total thickness (i.e., the total height) of the plate, but the equivalent thickness t of the plate eq , and the thickness t in formula ④ should also be taken as the equivalent thickness t eq . According to engineering experience, the maximum displacement of the plate is generally 1 to 5 times that of the equivalent thickness t eq . If only formula ⑤ is used to calculate the displacement, the result will be seriously distorted.

[0075] The present invention proposes a method for calculating the displacement of a polycarbonate U-shaped hollow plate. The calculation method is as follows:

[0076] Step 1: Measure and determine the basic parameters of the U-shaped hollow plate,

[0077] The basic parameters include dimensional parameters, plate type, form of the support connection point, load applied to the plate body, and load application direction.

[0078] The basic parameters in Step 1 include:

[0079] Dimensional parameters: width a of the plate, height h of the plate, thickness t of the upper surface layer 1 , thickness t of the lower surface layer 2 and height h of the centroid axis of the plate from the lower surface layer1 ;

[0080] The form of the plate type and the support connection point: a one-way plate with fixed hinge supports on opposite sides, which determines the form of the calculation model;

[0081] The load q on the plate is equivalent to the uniformly distributed load on the plate surface;

[0082] Load action direction: There are two forms: load action direction upward or load action direction downward, and the corresponding value of the adjustment coefficient γ has two ranges.

[0083] Step 2: Determine the equivalent thickness t of the plate based on the size parameters of the basic parameters in step 1. eq .

[0084] The plane layout and support connection points of the U-shaped hollow plate are as follows: Figure 1 As shown in the figure, L is the long side of the plate, that is, the direction of the rib, and a is the width of the plate.

[0085] At this time, determine the equivalent thickness t of the U-shaped hollow plate eq .

[0086] The cross-sectional structure of the U-shaped hollow plate is as follows: Figure 2 As shown, the cavity in the cross section is a mouth shape, similar to the hollow truss structure. The thickness of the upper surface layer 3 and the lower surface layer 4 of different brands varies, but is generally between 0.6mm and 0.9mm. The thickness of the middle layer 5 is generally between 0.15mm and 0.2mm. Figure 3 As shown, the deformation diagram is based on the plane section assumption, the influence of shear can be ignored, the deformation between layers can be coordinated and consistent, and the relative sliding between layers can be ignored.

[0087] Generally speaking, the thickness of the upper and lower surface layers is 3 to 6 times the thickness of the middle layer, and the upper and lower surface layers are farthest from the neutral axis. The vertical rib 2 is perpendicular to the short side span direction of the plate, see Figure 4 As shown. Therefore, the equivalent thickness t eq The calculation formula is simplified to only consider the influence of the upper and lower surface layers, and the equivalent thickness calculation formula can be applied to U-shaped hollow plates with different cavities.

[0088] Equivalent thickness of the plate t eq The calculation formula is as follows:

[0089] First determine h 1 :

[0090]

[0091] Then the h obtained in formula ② is 1 Substituting into formula ③, we get the equivalent thickness t eq :

[0092]

[0093] Where, t 1 is the thickness of the upper surface layer, t 2 is the thickness of the lower surface layer, h is the height of the plate, h 1 It is the height of the plate centroid from the lower surface layer.

[0094] Step 3: According to the equivalent thickness t of the plate obtained in step 2 eq， Determine the bending stiffness D of the plate.

[0095] The calculation formula of the bending stiffness D of the plate is as follows:

[0096]

[0097] Where D is the bending stiffness of the plate, E is the elastic modulus of the plate, and t is the equivalent thickness t eq , υ is Poisson's ratio.

[0098] Step 4: Determine the displacement reduction coefficient η. On the basis of the displacement calculation formula of the existing plate, set the displacement reduction coefficient η for the U-shaped hollow plate.

[0099] Step a, the displacement reduction factor η is considered to be directly related to the displacement ω / t eq As parameters,

[0100] The displacement reduction coefficient η is derived from The proportional relationship is as follows:

[0101] According to the calculation formula ④ of the bending stiffness D of the plate and the calculation formula ⑤ of the displacement of the plate, ω / t eq Converted into physical parameters related to the plate foundation parameters, the proportional conversion process is shown in formula ⑥:

[0102]

[0103]

[0104] Where: ω is the vertical displacement of the plate, μ is the flexure coefficient, υ is the Poisson's ratio, q is the load on the plate, a is the width of the plate, E is the elastic modulus of the plate, D is the bending stiffness of the plate, t eq is the equivalent thickness of the plate; Formula ⑥ is based on ω and Proportional to D is proportional, so and is proportional to; the displacement reduction coefficient η is converted into relationship curve.

[0105] Step b, at this time, the coefficient parameter θ is introduced to convert the displacement reduction coefficient η into physical parameters related to the size parameters in the basic parameters and the load on the plate.

[0106] In the formula, q is the load on the plate, a is the width of the plate, E is the elastic modulus of the plate, and t eq is the equivalent thickness of the plate;

[0107] The calculation formula of the displacement reduction coefficient η is fitted into a power function formula related to the coefficient parameter θ, and the value range of the displacement reduction coefficient η is obtained.

[0108] The specific process is as follows:

[0109] According to the test data of a U-shaped hollow board manufacturer, the Poisson's ratio of the material used in the product is υ=0.4, and the elastic modulus is E=2400Mpa. The U-shaped hollow board is a one-way board connected to the opposite sides. Select different load conditions and carry out the following steps:

[0110] First, the maximum mid-span displacement ω is calculated according to the plate displacement calculation formula ⑤ 1 ; Then, a one-way plate model with fixed hinge supports on opposite sides is established, and the geometric nonlinearity of large deformation is considered to calculate the maximum mid-span displacement ω 2 .

[0111] The calculation formula of displacement reduction coefficient η is as follows:

[0112]

[0113] In the formula, ω 1 The maximum mid-span displacement calculated by the plate displacement calculation formula ⑤;

[0114] ω 2 In order to consider the form of plate type and support connection point in the foundation parameters, a one-way plate model with fixed hinge supports on opposite sides is established, and the maximum mid-span displacement is calculated by finite element calculation considering large deformation geometric nonlinearity.

[0115] The data calculations of η and θ are shown in Tables 1 and 2.

[0116] Table 1 Values ​​of η and θ under downward load.

[0117] θ 3.36 5.28 16.81 25.15 26.41 30.26 39.51 47.54 58.1 η 0.97 0.90 0.69 0.58 0.57 0.53 0.47 0.43 0.39

[0118] Table 2 Values ​​of η and θ when the load acts in the upward direction.

[0119] θ 7.39 14.79 22.18 4.71 9.41 14.12 20.17 23.53 n 0.91 0.75 0.64 0.98 0.84 0.77 0.64 0.60

[0120] Create a scatter plot of the data of η and θ in Table 1 and Table 2. Based on the above data, see Figure 5As shown, the displacement reduction coefficient formula using power function fitting is shown in formula ⑨.

[0121] η=0.7e (-θ / 30) +0.3 ⑨;

[0122] As θ increases, η gradually decreases until it approaches 0.3, and the value range of η is 0.3 to 1.0. 2 Values ​​and adjusted R 2 The values ​​are all greater than 0.967, and the formula fits very well. 2 The coefficient of determination is the coefficient of determination, which is a statistic that measures the goodness of fit. The goodness of fit refers to the degree of fit of the regression line to the observed value. 2 The closer the value is to 1, the better the regression line fits the observed values.

[0123] Therefore, based on the calculation results of the classical theory of small plate deformation and the finite element calculation results considering geometric nonlinearity, the displacement reduction coefficient η is introduced to obtain the displacement calculation formula of the U-shaped hollow plate under large deformation. The displacement reduction coefficient η is only related to the coefficient parameter θ, which is related to the plate's own parameters and the load it is subjected to.

[0124] Step five, determine the adjustment coefficient γ, and determine the value range of the adjustment coefficient according to the load direction in the basic parameters in step one.

[0125] The calculation formula of the adjustment coefficient γ is as follows:

[0126]

[0127] In the formula, ω 2 In order to consider the form of plate type and support connection point in the foundation parameters, a one-way plate model with fixed hinge supports on opposite sides is established, and the maximum mid-span displacement of the finite element calculation is considered considering large deformation geometric nonlinearity;

[0128] ω 3 is the maximum mid-span displacement in the actual test comparison results.

[0129] The U-shaped hollow plates from two domestic manufacturers were used for the test. By comparing the test results with the finite element calculation results considering geometric nonlinearity, the adjustment coefficient γ=ω was introduced. 3 / ω 2 , γ is related to the direction of load.

[0130] The load acts in a downward direction, and the values ​​of γ are shown in Table 3.

[0131] Table 3 Calculated values ​​of γ when the load acts in the downward direction.

[0132]

[0133] Table 4 Calculated values ​​of γ when the load direction is upward.

[0134]

[0135] The comparison results are shown in Table 3 and Table 4. There is no obvious regularity between θ and γ, but the range of γ values ​​can be obtained. γ is based on the value when the U-shaped hollow plate is close to failure.

[0136] Therefore, when the load acts downward, the value range of γ is [1.1~1.3], and the preferred value is 1.1; when the load acts upward, the value range of γ is [1.3~1.5], and the preferred value is 1.5.

[0137] Step six, calculate and determine the mid-span vertical displacement ω of the U-shaped hollow plate.

[0138] The mid-span vertical displacement ω of the U-shaped hollow plate is obtained and calculated according to formula ①:

[0139]

[0140] Where μ is the deflection coefficient, q is the load on the plate, and a is the width of the plate in the dimensional parameters.

[0141] To illustrate the accuracy of the formula, the calculation results of the present invention by formula ①, the test value and the comparison results of the calculation results of the traditional plate calculation formula ⑤ are shown in FIG. Figures 6 to 8 shown.

[0142] Figure 6 The corresponding data are shown in Table 5.

[0143] Table 5 Calculation results when the load acts upward.

[0144]

[0145] from Figure 6 It can be seen that the calculation results of several methods are not much different from the experimental results. Because the value of θ is relatively small, the in-plane film stress is not obvious. The calculation result of γ=1.5 is closest to the experimental value.

[0146] Figure 7 The corresponding data are shown in Table 6.

[0147] Table 6 Calculation results when the load acts downward.

[0148]

[0149] from Figure 7It can be seen that when θ≤20, the calculation results of several methods are not much different from the test results, which is consistent with the comparison results when the load acts upward. As the value of θ increases, the difference between the calculation results of formula ① and the test values ​​becomes larger and larger, even reaching a difference of several times, while the calculation results of γ=1.1 are closest to the test values.

[0150] Figure 8 The corresponding data are shown in Table 7.

[0151] Table 7 Calculation results and test values ​​of the formula of the present invention.

[0152]

[0153] Next table:

[0154]

[0155] Therefore, when the load acts downward, γ takes a value of 1.1; when the load acts upward, γ takes a value of 1.5. The comparison results with the test values ​​are as follows: Figure 8 As shown, it can be seen that the value of γ is reasonable.

Claims

1. A method for calculating the displacement of a polycarbonate U-shaped hollow plate, characterized in that: The calculation method is as follows: Step 1: Measure and determine the basic parameters of the U-shaped hollow board. The foundation parameters include size parameters, plate type, form of support connection points, load on the plate and direction of load action; Step 2: Determine the equivalent thickness t of the plate based on the size parameters in the basic parameters of step 1. eq ; The cross section of the U-shaped hollow plate is the mouth-shaped cavity, and the equivalent thickness t is obtained eq Related to the size of the upper and lower surface layers; Step 3: According to the equivalent thickness t of the plate obtained in step 2 eq , determine the bending stiffness D of the plate; The calculation formula of the bending stiffness D of the plate is as follows: Where D is the bending stiffness of the plate, E is the elastic modulus of the plate, and t is the equivalent thickness t eq ,υ is Poisson’s ratio; Step 4: Determine the displacement reduction coefficient η, The displacement reduction factor η is considered to be directly related to the displacement ω / t eq is the parameter; According to the calculation formula ④ of the bending stiffness D of the plate and the calculation formula ⑤ of the displacement of the plate, ω / t eq Converted into physical parameters related to the basic parameters of the board, the proportional conversion process is shown in formula ⑥: Where: ω is the vertical displacement of the plate, μ is the deflection coefficient, q is the load on the plate, and a is the width of the plate. Formula ⑥ is based on ω and Proportional to D is proportional, so and is proportional to; the displacement reduction coefficient η is converted into The relationship curve of The coefficient parameter θ is introduced to convert the displacement reduction coefficient η into physical parameters related to the size parameters in the basic parameters and the load on the plate. The calculation formula of displacement reduction coefficient η is as follows: Where ω1 is the maximum mid-span displacement calculated by the plate displacement calculation formula ⑤; ω2 is the maximum mid-span displacement calculated by finite element calculation considering the form of plate type and support connection points in the foundation parameters, and the one-way plate model with fixed hinge supports on opposite sides is established; The calculation formula of the displacement reduction coefficient η is fitted into a power function formula related to the coefficient parameter θ, and the value range of the displacement reduction coefficient η is obtained; A scatter plot is established based on the data of η and θ, and the calculation formula of the displacement reduction coefficient η using power function fitting is as follows: η=0.7e (-θ / 30) +0.3⑨; The value range of η is 0.3~1.0; Step 5, determine the adjustment coefficient γ, and determine the value range of the adjustment coefficient according to the load action direction in the basic parameters in step 1; Step 6: Obtain and calculate the mid-span vertical displacement ω of the U-shaped hollow plate according to formula ①:

2. The displacement calculation method of the polycarbonate U-shaped hollow plate according to claim 1, characterized in that: The basic parameters in step 1 include: Dimensional parameters: plate width a, plate height h, upper surface layer thickness t1, lower surface layer thickness t2 and plate centroid height h1 from lower surface layer; The form of plate type and support connection point: a one-way plate with fixed hinge supports on opposite sides is used to determine the form of the calculation model; The load q on the plate is equivalent to the uniformly distributed load on the plate surface; Load action direction: There are two forms: load action direction upward or load action direction downward, and the corresponding value of the adjustment coefficient γ has two ranges.

3. The displacement calculation method of the polycarbonate U-shaped hollow plate according to claim 2, characterized in that: In step 2, the equivalent thickness of the plate is eq The calculation formula is as follows: First determine h1: Then substitute h1 obtained in formula ② into formula ③ to obtain the equivalent thickness t eq : Where t1 is the thickness of the upper surface layer, t2 is the thickness of the lower surface layer, h is the height of the plate, and h1 is the height of the plate centroid from the lower surface layer.

4. The displacement calculation method of the polycarbonate U-shaped hollow plate according to claim 1, characterized in that: In step 5, the calculation formula of the adjustment coefficient γ is as follows: Where ω2 is the maximum mid-span displacement of the finite element calculation considering the form of the plate type and the support connection point in the foundation parameters, and the one-way plate model with fixed hinge supports on the opposite sides is established; ω3 is the maximum mid-span displacement in the actual test comparison results.

5. The displacement calculation method of the polycarbonate U-shaped hollow plate according to claim 4, characterized in that: When the load acts downward, the value range of γ is [1.1~1.3], When the load acts upward, the value range of γ is [1.3~1.5].

6. The displacement calculation method of the polycarbonate U-shaped hollow plate according to claim 5, characterized in that: When the load acts downward, γ takes the value of 1.1; When the load acts upward, γ takes the value of 1.5.

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