A method for determining buckling failure of fixed-roof storage tanks

Abstract

The present invention discloses a method for determining buckling failure of fixed-roof storage tanks, which relates to the field of storage tank safety technology. The method comprises: obtaining the buckling mode of the fixed-roof storage tank under the action of second-order and multi-order harmonic settlement; performing Fourier decomposition on the measured uneven settlement to obtain the settlement amplitude of harmonics of different orders; drawing the harmonic settlement amplitude-radial displacement curve at the buckling position of the tank top to determine the critical settlement amplitude of the tank top, and on this basis constructing a tank top buckling failure criterion to determine the tank top buckling damage factor; drawing the harmonic settlement amplitude-radial displacement curve at the buckling position of the tank wall to determine the critical settlement amplitude of the tank wall, and on this basis constructing a tank wall buckling failure criterion to determine the tank wall buckling damage factor; and then determining whether buckling occurs in the fixed-roof storage tank and the location where buckling occurs. The present invention considers factors more comprehensively, thereby improving the accuracy of the buckling failure determination results of the fixed-roof storage tank.

Description

Technical Field

[0001] The present invention relates to the technical field of storage tank safety, and in particular to a method for determining buckling failure of a fixed-roof storage tank. Background Art

[0002] A fixed-roof storage tank is a vertical cylindrical tank with a welded top structure connected to the tank body, leaving the top stationary. Under the effects of the storage medium and the tank's gravity, fixed-roof tanks can experience various settlement deformations, such as uniform settlement, planar tilt settlement, and uneven settlement. Uneven settlement is the most detrimental, causing damage to the tank or causing functional failure. Therefore, establishing buckling and yield failure criteria for fixed-roof tanks under uneven settlement is crucial for ensuring their safe operation.

[0003] In the prior art, Marr proposed a control standard for uneven settlement: S = 11L 2 Y / (EH), where S is the maximum allowable value of uneven settlement, L is the arc length between uneven settlement detection points, Y is the yield strength of the tank wall steel, E is the elastic modulus, and H is the tank height. The specific implementation process of determining uneven settlement using this control standard includes: setting multiple uneven settlement detection points on the tank body surface and determining the arc length between the uneven settlement detection points; obtaining the tank height, elastic modulus, and yield strength of the tank wall steel through physical measurement, and combining the arc length between the uneven settlement detection points with the tank height, elastic modulus, and yield strength of the tank wall steel to obtain the maximum allowable value of uneven settlement, thereby formulating the buckling failure determination criteria for fixed-roof tanks.

[0004] The defects of the above-mentioned existing technology are: when determining the arc length between the uneven settlement detection points, only the relevant parameters of the tank body are considered, and the changes in the location where the uneven settlement of the tank occurs are not considered. As a result, the buckling failure judgment criteria for fixed-roof tanks are not accurate enough. Summary of the Invention

[0005] Based on this, it is necessary to provide a method for determining buckling failure of fixed-roof storage tanks to address the above technical issues.

[0006] An embodiment of the present invention provides a method for determining buckling failure of a fixed-roof storage tank, comprising:

[0007] Obtain the buckling modes of fixed-roof tanks under 2nd and multi-order harmonic settlement;

[0008] Obtain the measured uneven settlement suffered by the fixed roof tank, perform Fourier decomposition on the measured uneven settlement, and obtain the settlement amplitude C of different order harmonics n ;

[0009] According to the buckling mode of the fixed-roof tank under the action of the second-order harmonic settlement, the harmonic settlement amplitude-radial displacement curve of the tank top buckling position is drawn; the harmonic settlement amplitude-radial displacement curve of the tank top buckling position is combined with the influence of multi-order harmonic settlement on the radial displacement of the tank top position to obtain the critical settlement amplitude U of the fixed-roof tank top nc-buckle-r ; According to the critical settlement amplitude U of the fixed roof tank roof nc-buckle-r and the sedimentation amplitude C of different order harmonics n Construct the tank roof buckling failure criterion to determine the tank roof buckling damage factor CDF buckle-r ;

[0010] According to the buckling mode of fixed-roof tank under multi-order harmonic settlement, the harmonic settlement amplitude-radial displacement curve of the tank wall buckling position is drawn; the harmonic settlement amplitude-radial displacement curve of the tank wall buckling position is combined with the influence of the second-order harmonic settlement on the radial displacement of the tank wall position to obtain the critical settlement amplitude U of the fixed-roof tank wall. nc-buckle-w ; According to the critical settlement amplitude U of the fixed roof tank wall nc-buckle-w and the sedimentation amplitude C of different order harmonics n Construct the tank wall buckling failure criterion to determine the tank wall buckling damage factor CDF buckle-w ;

[0011] According to the tank roof buckling damage factor CDF buckle-r and tank wall buckling damage factor CDF buckle-w , determine whether and where buckling occurs in fixed roof tanks.

[0012] Optionally, the buckling modes of a fixed-roof tank under second-order and multi-order harmonic settlement are obtained, which includes:

[0013] A numerical model of the tank is established, and the arc length method is used to track the buckling behavior of the fixed-roof tank under harmonic settlement. The buckling behavior includes pre-buckling behavior, buckling critical point, and post-buckling behavior.

[0014] The buckling behaviors of fixed-roof storage tanks under second-order and multi-order harmonic settlement are analyzed respectively, and the buckling modes of the tanks at different orders are obtained.

[0015] Optionally, a harmonic settlement amplitude-radial displacement curve at the tank top buckling position is drawn based on the buckling mode of the fixed-roof tank under the action of the second-order harmonic settlement, including:

[0016] The harmonic settlement amplitude-radial displacement curve is drawn with the harmonic settlement amplitude of the tank top under the second-order harmonic settlement as the horizontal axis and the radial displacement of the tank top as the vertical axis;

[0017] Under the action of the second-order harmonic settlement, when the radial displacement of the tank roof reaches the tank roof buckling threshold RDRc, the tank roof buckles.

[0018] Optionally, according to the critical settlement amplitude U of the fixed-roof tank roof nc-buckle-r and the sedimentation amplitude C of different order harmonics n The tank roof buckling failure criterion is constructed and its calculation formula is:

[0019]

[0020] Among them, CDF buckle-r is the tank roof buckling damage factor, U nc-buckle-r is the critical settlement amplitude of the fixed roof tank roof, C n is the settlement amplitude of harmonics of different orders, n is the harmonic order;

[0021] When CDF buckle-r When CDF is greater than 1, the tank roof buckles; buckle-r When it is less than 1, the tank roof does not buckle.

[0022] Optionally, a harmonic settlement amplitude-radial displacement curve at the tank wall buckling position is drawn based on the buckling mode of the fixed-roof storage tank under the action of multi-order harmonic settlement, including:

[0023] The harmonic settlement amplitude-radial displacement curve is drawn with the harmonic settlement amplitude of the tank wall under multi-order harmonic settlement as the horizontal coordinate and the radial displacement of the tank wall as the vertical coordinate;

[0024] Under the action of multi-order harmonic sedimentation, when the radial displacement of the tank wall reaches the tank wall buckling threshold RDW c The tank wall buckles.

[0025] Alternatively, according to the critical settlement amplitude U of the fixed roof tank wall nc-buckle-w and the sedimentation amplitude C of different order harmonics n The tank wall buckling failure criterion is constructed, and its calculation formula is:

[0026]

[0027] Among them, CDF buckle-w is the tank wall buckling damage factor, U nc-buckle-w is the critical settlement amplitude of the fixed roof tank wall, C n is the settlement amplitude of harmonics of different orders, n is the harmonic order;

[0028] When CDF buckle-w When CDF is greater than 1, the tank wall buckles; buckle-w When it is less than 1, the tank wall does not buckle.

[0029] Optionally, determining whether buckling occurs in the fixed-roof storage tank and the location where the buckling occurs specifically includes:

[0030] As the measured differential settlement of fixed-roof tanks increases, the tank roof buckling damage factor CDF buckle-r Less than 1, tank wall buckling damage factor CDF buckle-w When it is less than 1, the fixed-roof tank does not buckle;

[0031] As the measured differential settlement of fixed-roof tanks increases, the tank roof buckling damage factor CDF buckle-r Greater than 1, tank wall buckling damage factor CDF buckle-w When it is less than 1, the tank roof buckles but the tank wall does not buckle;

[0032] As the measured differential settlement of fixed-roof tanks increases, the tank roof buckling damage factor CDF buckle-r Less than 1, tank wall buckling damage factor CDF buckle-w When it is greater than 1, the tank roof does not buckle, but the tank wall buckles.

[0033] The above-mentioned method for determining buckling failure of a fixed-roof storage tank provided by the embodiment of the present invention has the following beneficial effects compared with the prior art:

[0034] The present invention draws a harmonic settlement amplitude-radial displacement curve at a tank top buckling position based on the buckling mode of a fixed-roof storage tank under the action of second-order harmonic settlement, determines the critical settlement amplitude of the tank top of the fixed-roof storage tank, and constructs a tank top buckling failure criterion on this basis to determine the tank top buckling damage factor; draws a harmonic settlement amplitude-radial displacement curve at a tank wall buckling position based on the buckling mode of the fixed-roof storage tank under the action of multi-order harmonic settlement, determines the critical settlement amplitude of the tank wall of the fixed-roof storage tank, and constructs a tank wall buckling failure criterion on this basis to determine the tank wall buckling damage factor; and determines whether buckling occurs in the fixed-roof storage tank and the location where buckling occurs based on the tank top buckling damage factor and the tank wall buckling damage factor.

[0035] Compared with the existing technology, the above process takes into account the influence of multi-order harmonic settlement on the radial displacement of the tank top position when constructing the tank top buckling failure criterion under the action of second-order harmonic settlement; takes into account the influence of second-order harmonic settlement on the radial displacement of the tank wall position when constructing the tank wall buckling failure criterion under the action of multi-order harmonic settlement; and takes into account the influence of second-order and multi-order harmonic settlement on the radial displacement of both the tank top and the tank wall of the fixed-roof tank. The factors considered are more comprehensive, which improves the accuracy of the buckling failure judgment results of the fixed-roof tank. The method is simple and convenient for engineering application. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 A schematic flow chart of a method for determining buckling failure of a fixed-roof storage tank provided in one embodiment;

[0037] Figure 2A buckling modal diagram of a fixed-roof storage tank under harmonic settlement in a buckling failure determination method for a fixed-roof storage tank provided in one embodiment is shown. Figure 2 (a) in the figure is the buckling mode under the second-order harmonic settlement. Figure 2 (b) is the buckling mode under the action of the third-order harmonic settlement. Figure 2 (c) in the figure is the buckling mode under the action of the fourth-order harmonic settlement. Figure 2 (d) in the figure is the buckling mode under the fifth-order harmonic settlement. Figure 2 (e) in the equation is the buckling mode under the action of the 6th harmonic settlement. Figure 2 (f) in the equation is the buckling mode under the action of the 7th harmonic settlement. Figure 2 (g) in the figure is the buckling mode under the action of 8th-order harmonic settlement;

[0038] Figure 3 A settlement-displacement curve diagram of a tank wall buckling position for a method for determining buckling failure of a fixed-roof storage tank provided in one embodiment;

[0039] Figure 4 A method for determining buckling failure of a fixed roof storage tank provided in an embodiment is provided. 2c-buckle-w Schematic diagram of the calculation process;

[0040] Figure 5 A settlement-displacement curve diagram of a tank roof buckling position for a method for determining buckling failure of a fixed-roof storage tank provided in one embodiment;

[0041] Figure 6 A method for determining buckling failure of a fixed roof storage tank provided in an embodiment is provided. 3c-buckle-r Schematic diagram of the calculation process;

[0042] Figure 7 FIG1 is a load proportional factor-displacement curve diagram of a method for determining buckling failure of a fixed-roof storage tank provided in one embodiment. Figure 7 (a) in the equation is the buckling mode, Figure 7 (b) in the figure is the load proportional factor-displacement curve. DETAILED DESCRIPTION

[0043] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0044] In one embodiment, a method for determining buckling failure of a fixed roof tank is provided, such as Figure 1 As shown, the method includes:

[0045] Step 1: Obtain the buckling modes of the fixed-roof tank under second-order and multi-order harmonic settlement.

[0046] Step 2: Obtain the measured uneven settlement suffered by the fixed-roof tank, perform Fourier decomposition on the measured uneven settlement, and obtain the settlement amplitude C of different order harmonics. n .

[0047] Step 3: Draw the harmonic settlement amplitude-radial displacement curve of the tank top buckling position according to the buckling mode of the fixed-roof tank under the action of the second-order harmonic settlement; the harmonic settlement amplitude-radial displacement curve of the tank top buckling position is combined with the influence of multi-order harmonic settlement on the radial displacement of the tank top position to obtain the critical settlement amplitude U of the fixed-roof tank top. nc-buckle-r ; According to the critical settlement amplitude U of the fixed roof tank roof nc-buckle-r and the sedimentation amplitude C of different order harmonics n Construct the tank roof buckling failure criterion to determine the tank roof buckling damage factor CDF buckle-r .

[0048] The harmonic settlement amplitude-radial displacement curve is plotted with the harmonic settlement amplitude of the tank roof under second-order harmonic settlement as the horizontal axis and the radial displacement of the tank roof as the vertical axis. Under the action of second-order harmonic settlement, when the radial displacement of the tank roof reaches the tank roof buckling threshold (RDRc), the tank roof buckles.

[0049] Step 4: Draw the harmonic settlement amplitude-radial displacement curve at the buckling position of the tank wall according to the buckling mode of the fixed-roof tank under the action of multi-order harmonic settlement; the harmonic settlement amplitude-radial displacement curve at the buckling position of the tank wall is combined with the influence of the second-order harmonic settlement on the radial displacement of the tank wall position to obtain the critical settlement amplitude U of the fixed-roof tank wall. nc-buckle-w ; According to the critical settlement amplitude U of the fixed roof tank wall nc-buckle-w and the sedimentation amplitude C of different order harmonics n Construct the tank wall buckling failure criterion to determine the tank wall buckling damage factor CDF buckle-w .

[0050] Among them, the harmonic settlement amplitude of the tank wall under multi-order harmonic settlement is used as the horizontal coordinate, and the radial displacement of the tank wall is used as the vertical coordinate to draw the harmonic settlement amplitude-radial displacement curve. Under the action of multi-order harmonic settlement, when the radial displacement of the tank wall reaches the tank wall buckling threshold RDW, c The tank wall buckles.

[0051] Step 5: Based on the tank top buckling damage factor CDF buckle-r and tank wall buckling damage factor CDF buckle-w , determine whether and where buckling occurs in fixed roof tanks.

[0052] As the measured differential settlement of fixed-roof tanks increases, the tank roof buckling damage factor CDF buckle-r Less than 1, tank wall buckling damage factor CDF buckle-w When it is less than 1, the fixed roof tank does not buckle.

[0053] As the measured differential settlement of fixed-roof tanks increases, the tank roof buckling damage factor CDF buckle-r Greater than 1, tank wall buckling damage factor CDF buckle-w When it is less than 1, the tank top buckles but the tank wall does not buckle.

[0054] As the measured differential settlement of fixed-roof tanks increases, the tank roof buckling damage factor CDF buckle-r Less than 1, tank wall buckling damage factor CDF buckle-w When it is greater than 1, the tank roof does not buckle, but the tank wall buckles.

[0055] A specific embodiment of the present invention is provided:

[0056] (1) A numerical model of the tank is established, and the arc length method is used to track the pre-buckling behavior, buckling critical point, and post-buckling behavior of the tank under harmonic settlement.

[0057] (2) Buckling analysis, such as Figure 2 As shown, for 10000m 3 The buckling modes of fixed roof tanks under 2nd to 8th order harmonic settlement were analyzed, and the buckling modes of tanks at different orders were determined.

[0058] Figure 2 (a) in the figure is the buckling mode under the second-order harmonic settlement. Figure 2 (b) is the buckling mode under the action of the third-order harmonic settlement. Figure 2 (c) in the figure is the buckling mode under the action of the fourth-order harmonic settlement. Figure 2 (d) in the figure is the buckling mode under the fifth-order harmonic settlement. Figure 2 (e) in the equation is the buckling mode under the action of the 6th harmonic settlement. Figure 2 (f) in the equation is the buckling mode under the action of the 7th harmonic settlement. Figure 2 (g) in the figure is the buckling mode under the action of 8th-order harmonic settlement.

[0059] Buckling occurs at the bottom of the tank wall under 3rd to 8th order harmonic settlement, and at the top of the tank under 2nd order harmonic settlement. Because buckling occurs at different locations under different order harmonic settlements, it is necessary to establish corresponding buckling failure criteria for different buckling locations.

[0060] (3) Establishment of tank wall buckling criterion

[0061] The harmonic settlement amplitude-radial displacement curve at the tank wall buckling position is as follows: Figure 3 As shown in the figure, under the action of harmonic settlement, the harmonic settlement amplitude-radial displacement curve initially changes linearly. After reaching the critical harmonic settlement amplitude, the radial displacement increases rapidly. Under the action of multi-order (n=3, 4, 5, 6, 7, 8) harmonic settlement, when the radial displacement of the tank wall reaches the tank wall buckling threshold RDW, the radial displacement of the tank wall reaches the tank wall buckling threshold RDW. c When , the tank wall buckles. Since the uneven settlement can be expressed as the superposition value of harmonic settlement of different orders through the Fourier basis, the tank wall buckling failure criterion under the action of uneven settlement can be expressed as:

[0062]

[0063] Among them, CDF buckle-w is the tank wall buckling damage factor, U nc-buckle-w is the critical settlement amplitude of the fixed roof tank wall, C n is the sedimentation amplitude of different order harmonics, n is the harmonic order. buckle-w When CDF is greater than 1, the tank wall buckles; buckle-w When it is less than 1, the tank wall does not buckle.

[0064] Through the tank buckling modal analysis, it can be found that although the buckling position of the tank occurs at the tank top under the action of the second-order harmonic settlement, it is necessary to consider the influence of the radial displacement of the tank wall caused by the second-order harmonic settlement on the tank wall buckling. 2c-buckle-w It cannot be directly obtained by numerical techniques, but can be obtained by Figure 4 The method provided determines U 2c-buckle-w First, you can Figure 4 Determine the tank wall buckling threshold RDW c ; Then, extend the linear part of the harmonic settlement amplitude-radial displacement curve; Finally, determine U 2c-buckle-w Value, U 2c-buckle-w Values ​​are only used to calculate CDF buckle-w , and has no actual physical meaning. Figure 4 The unloading of the nonlinear part is caused by the unloading of the tank wall after the tank roof buckles. Table 1 lists the U nc-buckle-w The value of .

[0065] Table 1U nc-buckle-w value

[0066] <![CDATA[U 2c-buckle-w ]]> <![CDATA[U 3c-buckle-w ]]> <![CDATA[U 4c-buckle-w ]]> <![CDATA[U 5c-buckle-w ]]> <![CDATA[U 6c-buckle-w ]]> <![CDATA[U 7c-buckle-w ]]> <![CDATA[U 8c-buckle-w ]]> 12.5mm 3.9mm 2.9mm 2.1mm 1.7mm 1.4mm 1.1mm

[0067] (4) Tank roof buckling criterion

[0068] The harmonic settlement amplitude-radial displacement curve of a fixed roof tank under the action of second-order harmonic settlement is as follows: Figure 5 As shown in Figure 1, it is assumed that when the radial displacement of the tank roof reaches the tank roof buckling threshold RDRc, the tank roof buckles. Similarly, the influence of the radial displacement of the tank roof position caused by the harmonic settlement of order n=3, 4, 5, 6, 7, and 8 on the tank wall buckling is considered to establish the buckling criterion of the tank roof under the action of uneven settlement. Determine U 3c-buckle-r The process and U 2c-buckle-w Same, such as Figure 6 As shown, U 4c-buckle-r , U 5c-buckle-r with U 6c-buckle-r The determination process will not be repeated. Under the action of n=7,8 order harmonic settlement, the radial direction of the tank roof is extremely small and can be ignored. The failure criterion for the tank roof buckling under uneven settlement can be expressed as:

[0069]

[0070] Among them, CDF buckle-r is the tank roof buckling damage factor, U nc-buckle-r is the critical settlement amplitude of the fixed roof tank roof, C n is the sedimentation amplitude of different order harmonics, n is the harmonic order. buckle-r When CDF is greater than 1, the tank roof buckles; buckle-r When it is less than 1, the tank roof does not buckle. Table 2 lists the U nc-buckle-r The value of .

[0071] Table 2U nc-buckle-r value

[0072] <![CDATA[U 2c-buckle-r ]]> <![CDATA[U 3c-buckle-r ]]> <![CDATA[U 4c-buckle-r ]]> <![CDATA[U 5c-buckle-r ]]> <![CDATA[U 6c-buckle-r ]]> <![CDATA[U 7c-buckle-r ]]> <![CDATA[U 8c-buckle-r ]]> 5.5mm 7.7mm 19.4mm 25.8mm 60.6mm 0 0

[0073] For example, Figure 7 As shown, Figure 7 (a) in the equation is the buckling mode, Figure 7 (b) is the load proportional factor-displacement curve. The proposed method is used to calculate whether the tank will buckle under the action of measured uneven settlement, and the calculation results are verified using finite element calculation. The settlement detection points of the selected tank settlement cases are 12, and the Fourier basis is used to decompose them to obtain the harmonic settlement amplitude. See Table 3, calculate CDF respectively. buckle-w , CDF buckle-r value.

[0074] Table 3 Harmonic Subsidence Amplitude

[0075] <![CDATA[C0]]> <![CDATA[C1]]> <![CDATA[C2]]> <![CDATA[C3]]> <![CDATA[C4]]> <![CDATA[C5]]> <![CDATA[C6]]> Case 1 11.7 12.1 7.7 3.4 2.1 1.9 2.3

[0076] For Case 1, CDF buckle-w The value of is 4.47, CDF buckle-r The value is 2.06, CDFbuckle-w Greater than CDF buckle-r , indicating that the tank wall buckles first. Further analysis shows that the tank wall begins to buckle when the load scale factor is 0.22 (= 1 / 4.47). Finite element calculation results show that the tank roof begins to buckle when the load scale factor is 0.3.

[0077] The load scale factor is a variable value. buckle-r and tank wall buckling damage factor CDF buckle-w When both are less than 1, the load proportional factor can be used to amplify them simultaneously and observe the order of the two factors being greater than 1. buckle-r If the tank wall buckling damage factor CDF is greater than 1, the tank roof buckles; if the tank wall buckling damage factor CDF buckle-w If it is greater than 1, the tank wall will buckle.

[0078] The above-described embodiments merely illustrate several implementations of the present invention. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, and all such variations and improvements fall within the scope of protection of the present invention.

Claims

1. A method for determining buckling failure of a fixed-roof storage tank, characterized in that: include: Obtain the buckling modes of fixed-roof tanks under 2nd and multi-order harmonic settlement; Obtain the measured uneven settlement suffered by the fixed roof tank, perform Fourier decomposition on the measured uneven settlement, and obtain the settlement amplitude C of different order harmonics n ; According to the buckling mode of the fixed-roof tank under the action of the second-order harmonic settlement, the harmonic settlement amplitude-radial displacement curve of the tank top buckling position is drawn; the harmonic settlement amplitude-radial displacement curve of the tank top buckling position is combined with the influence of multi-order harmonic settlement on the radial displacement of the tank top position to obtain the critical settlement amplitude U of the fixed-roof tank top nc-buckle-r ; According to the critical settlement amplitude U of the fixed roof tank roof nc-buckle-r and the sedimentation amplitude C of different order harmonics n Construct the tank roof buckling failure criterion to determine the tank roof buckling damage factor CDF buckle-r ; According to the buckling mode of fixed-roof tank under multi-order harmonic settlement, the harmonic settlement amplitude-radial displacement curve of the tank wall buckling position is drawn; the harmonic settlement amplitude-radial displacement curve of the tank wall buckling position is combined with the influence of the second-order harmonic settlement on the radial displacement of the tank wall position to obtain the critical settlement amplitude U of the fixed-roof tank wall. nc-buckle-w ; According to the critical settlement amplitude U of the fixed roof tank wall nc-buckle-w and the sedimentation amplitude C of different order harmonics n Construct the tank wall buckling failure criterion to determine the tank wall buckling damage factor CDF buckle-w ; According to the tank roof buckling damage factor CDF buckle-r and tank wall buckling damage factor CDF buckle-w , determine whether and where buckling occurs in fixed roof tanks.

2. A method for determining buckling failure of a fixed-roof storage tank according to claim 1, characterized in that: The method of obtaining the buckling mode of the fixed-roof storage tank under the action of second-order and multi-order harmonic settlement includes: A numerical model of the tank is established, and the arc length method is used to track the buckling behavior of the fixed-roof tank under harmonic settlement. The buckling behavior includes pre-buckling behavior, buckling critical point, and post-buckling behavior. The buckling behaviors of fixed-roof storage tanks under second-order and multi-order harmonic settlement are analyzed respectively, and the buckling modes of the tanks at different orders are obtained.

3. The method for determining buckling failure of a fixed-roof storage tank according to claim 1, wherein: The method of drawing a harmonic settlement amplitude-radial displacement curve at the tank top buckling position according to the buckling mode of the fixed-roof storage tank under the action of the second-order harmonic settlement includes: The harmonic settlement amplitude-radial displacement curve is drawn with the harmonic settlement amplitude of the tank top under the second-order harmonic settlement as the horizontal axis and the radial displacement of the tank top as the vertical axis; Under the action of the second-order harmonic settlement, when the radial displacement of the tank roof reaches the tank roof buckling threshold RDRc, the tank roof buckles.

4. The method for determining buckling failure of a fixed-roof storage tank according to claim 1, wherein: The critical settlement amplitude U of the fixed roof tank roof is nc-buckle-r and the sedimentation amplitude C of different order harmonics n The tank roof buckling failure criterion is constructed and its calculation formula is: Among them, CDF buckle-r is the tank roof buckling damage factor, U nc-buckle-r is the critical settlement amplitude of the fixed roof tank roof, C n is the settlement amplitude of harmonics of different orders, n is the harmonic order; When CDF buckle-r When CDF is greater than 1, the tank roof buckles; buckle-r When it is less than 1, the tank roof does not buckle.

5. The method for determining buckling failure of a fixed-roof storage tank according to claim 1, wherein: The method of drawing a harmonic settlement amplitude-radial displacement curve at the tank wall buckling position according to the buckling mode of the fixed-roof storage tank under the action of multi-order harmonic settlement includes: The harmonic settlement amplitude-radial displacement curve is drawn with the harmonic settlement amplitude of the tank wall under multi-order harmonic settlement as the horizontal coordinate and the radial displacement of the tank wall as the vertical coordinate; Under the action of multi-order harmonic sedimentation, when the radial displacement of the tank wall reaches the tank wall buckling threshold RDW c The tank wall buckles.

6. The method for determining buckling failure of a fixed-roof storage tank according to claim 1, wherein: The critical settlement amplitude U of the fixed roof tank wall nc-buckle-w and the sedimentation amplitude C of different order harmonics n The tank wall buckling failure criterion is constructed, and its calculation formula is: Among them, CDF buckle-w is the tank wall buckling damage factor, U nc-buckle-w is the critical settlement amplitude of the fixed roof tank wall, C n is the settlement amplitude of harmonics of different orders, n is the harmonic order; When CDF buckle-w When CDF is greater than 1, the tank wall buckles; buckle-w When it is less than 1, the tank wall does not buckle.

7. The method for determining buckling failure of a fixed-roof storage tank according to claim 1, wherein: Determining whether buckling occurs in the fixed-roof storage tank and the location where buckling occurs specifically includes: As the measured differential settlement of fixed-roof tanks increases, the tank roof buckling damage factor CDF buckle-r Less than 1, tank wall buckling damage factor CDF buckle-w When it is less than 1, the fixed-roof tank does not buckle; As the measured differential settlement of fixed-roof tanks increases, the tank roof buckling damage factor CDF buckle-r Greater than 1, tank wall buckling damage factor CDF buckle-w When it is less than 1, the tank roof buckles but the tank wall does not buckle; As the measured differential settlement of fixed-roof tanks increases, the tank roof buckling damage factor CDF buckle-r Less than 1, tank wall buckling damage factor CDF buckle-w When it is greater than 1, the tank roof does not buckle, but the tank wall buckles.

Images