A tower support structure resistant to explosion loads and its design method

Abstract

The present invention provides a tower support structure resistant to explosion loads and a design method thereof. The tower comprises a plurality of pads connected to a tower body, a support plate connected to the pads, and an upper support ring and a lower support ring connected to the tower body; the upper support ring and the lower support ring are both connected to the pads and to the upper and lower ends of the support plates, respectively. The tower support structure resistant to explosion loads provided by the present invention provides strong support for the tower and has a strong ability to resist explosion wind pressure loads. It can share a large portion of the explosion wind pressure load with anchor bolts, thereby significantly reducing the number and specifications of anchor bolts, significantly reducing the thickness of the skirt, and reducing the requirements for on-site foundation pouring.

Description

Technical Field

[0001] The present invention relates to the technical field of towers, and in particular to an explosion-load-resistant tower support structure and a design method thereof. Background Art

[0002] Towers are one of the most common chemical equipment in the petrochemical industry, and their height-to-diameter ratio is generally greater than 10. With the development of the times, the design conditions of towers have become increasingly stringent. For example, some towers used in offshore platform modules have added explosion wind pressure loads. The so-called "explosion wind pressure load" refers to the explosion of other equipment near the tower, which causes the air to compress and spread in all directions, thereby generating an instantaneous wind pressure P on the tower. b The instantaneous wind pressure will be much greater than the normal natural wind, which will pose a great hidden danger to the safety of the tower itself.

[0003] The traditional design method for towers to withstand wind pressure and earthquakes involves using a large number of anchor bolts evenly distributed around the circumference to secure the skirt to the foundation (or steel structure). However, when subjected to explosive loads, the existing anchor bolt connection method often fails to meet the required strength requirements for the tower skirt. Even if the strength requirements are met, the number and specifications of the required anchor bolts are often very large, and it may even be impossible to arrange the required number of anchor bolts around the circumference. Clearly, relying solely on anchor bolts is no longer sufficient to meet the design conditions for explosive loads on towers. Summary of the Invention

[0004] The first object of the present invention is to disclose a tower support structure that is resistant to explosion loads. The structure provides strong support for the tower and has a strong ability to resist explosion wind pressure loads. It can share a large part of the explosion wind pressure load for the anchor bolts, thereby greatly reducing the number and specifications of the anchor bolts, significantly reducing the thickness of the skirt, and reducing the requirements for on-site foundation pouring.

[0005] To achieve the above-mentioned objectives, the present invention provides a tower support structure that is resistant to explosion loads, comprising a plurality of pads connected to the tower barrel, a support plate connected to the pads, and an upper support ring and a lower support ring connected to the tower barrel; the upper support ring and the lower support ring are both connected to the pads and are respectively connected to the upper and lower ends of the support plates.

[0006] In some embodiments, Teflon plates are attached to both sides of the support plate.

[0007] In some embodiments, the backing plate and the tower barrel are welded by fillet welds.

[0008] In some embodiments, the backing plate and the support plate are welded by a full penetration weld.

[0009] In some embodiments, the upper support ring and the tower barrel, the backing plate, and the support plate are all welded by fillet welds.

[0010] In some embodiments, the lower support ring and the tower barrel, the backing plate, and the support plate are all welded by fillet welds.

[0011] In some embodiments, the upper support ring and the lower support ring are both metal rings.

[0012] In some embodiments, a caliper for clamping the support plate is further included.

[0013] In some embodiments, the support plate is a steel plate.

[0014] In some embodiments, the base plate is located at a mid-height of the tower barrel.

[0015] The second object of the present invention is to disclose a design method for a tower support structure resistant to explosion loads, and to calculate a tower support structure with optimal strength through modeling, mechanical analysis, finite element analysis and other processes.

[0016] To achieve the above object, the present invention discloses a design method for a tower support structure resistant to explosion loads, comprising the following steps:

[0017] Step 1: Use pressure vessel strength calculation software to model the tower and calculate the first-order natural vibration period T of the tower under working conditions;

[0018] Step 2: Set the explosion wind pressure P dynamic Equivalent to static wind pressure P static

[0019] P static =P dynamic ×C D ×DLF

[0020] Among them, P dynamic ——provided by design conditions, unit bar,

[0021] C D [1] ——Drag coefficient of explosion wind load, take 1,

[0022] DLF [1] ——Dynamic load factor, the value range of DLF is 0 to 2;

[0023] Step 3: Substitute the equivalent static wind load P calculated in step 2 static Substitute the calculations from step 1 to calculate the explosion wind pressure thrusts F1, F2, F3...Fi on each segment of the tower (dividing the tower into several segments 1 to i, with each segment length h_i);

[0024] Step 4: Calculate for each segment: q1 = F1 / h_1, q2 = F2 / h_2, q3 = F2 / h_3...qi = Fi / h_i, unit N / m;

[0025] Step 5: Bring q1, q2, q3...qi in step 4 as line loads into the Ansys finite element software for calculation;

[0026] Step 6: Extract the force F at the support structure calculated by finite element method support ;

[0027] Step 7: Check the cross-sectional strength of the supporting structure.

[0028] In some embodiments, the pressure vessel strength calculation software in step 1 is PV Elite software.

[0029] In some embodiments, the value of DLF in step 2 ranges from 0.5 to 1.5.

[0030] In some embodiments, the finite element model in step 5 uses beam elements, the nodes of the support structure use hinged supports, the bottom nodes of the tower use fixed supports, and the constraints of the finite element model are:

[0031] (1) Support structure nodes: ux = 0, uy = 0, uz = 0,

[0032] (2) Bottom node: ux=0, uy=0, uz=0, urx=0, ury=0, urz=0.

[0033] In some embodiments, the cross-sectional strength check of the support structure in step seven is divided into:

[0034] (1) Longitudinal section strength check:

[0035] Shear stress τ on the longitudinal section b-b :

[0036]

[0037] Maximum tensile stress σ on the longitudinal section b-b :

[0038]

[0039] Combined normal stresses σ1 and σ2 on the longitudinal section:

[0040]

[0041]

[0042] According to the third strength theory, the longitudinal section can meet the strength requirements by ensuring the following formula is true:

[0043] |σ1-σ2|≤0.9[σ s ]

[0044] Among them: tr——the thickness of the support plate in mm,

[0045] hr——the height of the support plate in mm,

[0046] wr——the width of the support plate that leaks out of the upper and lower support rings (mm),

[0047] [σ s ]——yield strength of support plate material at room temperature, MPa;

[0048] (2) Transverse section strength check:

[0049] Shear stress τ on the transverse section c-c :

[0050]

[0051] Maximum tensile stress σ on the transverse section c-c :

[0052]

[0053] Combined normal stresses σ3 and σ4 on the transverse section:

[0054]

[0055] According to the third strength theory, the transverse section can meet the strength requirements by ensuring the following formula is true:

[0056] |σ3-σ4|≤0.9[σ s ]

[0057] Among them: tr——the thickness of the support plate in mm,

[0058] hr——the height of the support plate in mm,

[0059] tc——Thickness of upper support ring and lower support ring in mm,

[0060] Le——Effective support range of upper support ring and lower support ring in mm,

[0061]

[0062] [σ s ]——Yield strength of support plate material at room temperature, MPa,

[0063] tp——thickness of pad in mm;

[0064] wk——width of support plate mm

[0065] Compared with the prior art, the beneficial effects of the present invention are as follows: the tower support structure with explosion load resistance provided by the present invention has strong support for the tower, strong resistance to explosion wind pressure load, and can share a large part of the explosion wind pressure load for the anchor bolts, thereby greatly reducing the number and specifications of the anchor bolts, and can significantly reduce the thickness of the skirt, and can also reduce the on-site casting requirements for the foundation. BRIEF DESCRIPTION OF THE DRAWINGS

[0066] Figure 1 This is a structural diagram of a tower support structure capable of resisting explosion loads according to the present invention;

[0067] Figure 2 for Figure 1 A schematic structural diagram of the support structure shown in FIG;

[0068] Figure 3 for Figure 2 Middle AA section view;

[0069] Figure 4 for Figure 3 Enlarged view of the part marked B;

[0070] Figure 5 It is a schematic diagram of tower sections shown in the present invention;

[0071] Figure 6 Schematic diagram of the constraint conditions of the finite element model shown in the present invention;

[0072] Figure 7 This is a schematic diagram of the cross-section BB structure shown in the present invention;

[0073] Figure 8 It is a schematic diagram of the cross-section CC structure shown in the present invention;

[0074] Figure 9 Schematic diagram of equivalent wind pressure in Example 2 of the present invention. DETAILED DESCRIPTION

[0075] The present invention is described in detail below with reference to the various embodiments shown in the accompanying drawings, but it should be noted that these embodiments are not limitations of the present invention, and any equivalent transformations or substitutions in functions, methods, or structures made by ordinary technicians in this field based on these embodiments are all within the scope of protection of the present invention.

[0076] Example 1

[0077] like Figure 1-4A tower support structure resistant to explosion loads is shown, wherein the support structure 2 includes four pads 3 connected to the tower barrel 1, support plates 4 connected to the pads 3, and an upper support ring 5 and a lower support ring 6 connected to the tower barrel 1.

[0078] The four pads 3 are evenly spaced and arranged around the outer wall of the tower cylinder 1. The four pads 3 are located on the same horizontal plane. The support structure 2 is located at the middle height of the tower cylinder 1 and has the strongest ability to resist explosion wind pressure load.

[0079] The upper support ring 5 and the lower support ring 6 are both connected to the backing plate 3 and are respectively connected to the upper and lower ends of the support plate 4. The upper support ring 5 and the lower support ring 6 are both metal rings. The support plate 4 is a steel plate.

[0080] The pad 3 and the tower barrel 1 are welded by fillet welds; the pad 3 and the support plate 4 are welded by full penetration welds; the upper support ring 5 and the tower barrel 1, the upper support ring 5 and the pad 3, the upper support ring 5 and the support plate 4 are all welded by fillet welds; the lower support ring 6 and the tower barrel 1, the lower support ring 6 and the pad 3, the lower support ring 6 and the support plate 4 are all welded by fillet welds; thereby, the tower barrel 1, the pad 3, the support plate 4, the upper support ring 5, and the lower support ring 6 form an integrated structure, which is firm and stable.

[0081] It also includes a clamp 7 for clamping the support plate 4. The four support plates 4 are evenly distributed, so that the support structure 2 is firm and stable and not easy to fall over, thereby providing strong support for the tower cylinder 1 and having strong resistance to explosion wind pressure load. It can share a large part of the explosion wind pressure load for the anchor bolts, thereby greatly reducing the number and specifications of the anchor bolts, and significantly reducing the thickness of the skirt, and also reducing the requirements for pouring the foundation on site.

[0082] Teflon plates 8 are attached to both sides of the support plate 4 , and the Teflon plates 8 enable the support plate 4 and the caliper 7 to slide freely relative to each other without friction.

[0083] like Figure 5-8 The present invention discloses a method for designing a tower support structure resistant to explosion loads, comprising the following steps:

[0084] Step 1: Use pressure vessel strength calculation software to model the tower and calculate the first-order natural vibration period T of the tower under working conditions;

[0085] Step 2: Set the explosion wind pressure P dynamic Equivalent to static wind pressure P static

[0086] P static =P dynamic ×C D ×DLF

[0087] Among them, P dynamic ——provided by design conditions, unit bar,

[0088] C D [1] ——Drag coefficient of explosion wind load, take 1,

[0089] DLF [1] ——Dynamic load factor, the value range of DLF is 0 to 2;

[0090] Step 3: Substitute the equivalent static wind load P calculated in step 2 static Substitute into step 1 to calculate the various sections of the tower (such as Figure 5 As shown, the tower is divided into several segments 1 to i, and the length of each segment is h_i). The explosion wind pressure thrust F1, F2, F3...Fi is received;

[0091] Step 4: Calculate for each segment: q1 = F1 / h_1, q2 = F2 / h_2, q3 = F2 / h_3...qi = Fi / h_i, unit N / m;

[0092] Step 5: Bring q1, q2, q3...qi in step 4 as line loads into the Ansys finite element software for calculation;

[0093] Step 6: Extract the force F at the support structure calculated by finite element method support ;

[0094] Step 7: Check the cross-sectional strength of the supporting structure.

[0095] The pressure vessel strength calculation software in step 1 is PV Elite software. The DLF value in step 2 is in the range of 0.5 to 1.5, which can be selected according to the design data.

[0096] like Figure 6 As shown, in step 5, the finite element model adopts beam elements, the nodes of the support structure adopt hinged supports, the bottom nodes of the tower adopt fixed supports, and the constraints of the finite element model are as follows:

[0097] (1) Support structure nodes: ux = 0, uy = 0, uz = 0,

[0098] (2) Bottom node: ux=0, uy=0, uz=0, urx=0, ury=0, urz=0.

[0099] like Figure 7-8 As shown, the cross-sectional strength check of the support structure in step seven is divided into:

[0100] (1) Longitudinal section strength check:

[0101] The longitudinal section is as follows Figure 7 Section BB shown:

[0102] Shear stress τ on section BB b-b :

[0103]

[0104] Maximum tensile stress σ on section BB b-b :

[0105]

[0106] Combined normal stresses σ1 and σ2 on section BB:

[0107]

[0108]

[0109] According to the third strength theory, cross-section BB can meet the strength requirements if the following formula is established:

[0110] |σ1-σ2|≤0.9[σ s ]

[0111] Where: tr——the thickness of the support plate 4 in mm,

[0112] hr——the height of the support plate 4 in mm,

[0113] wr——the width of the support plate 4 leaking out of the upper and lower support rings in mm,

[0114] [σ s ]——Yield strength of support plate 4 material at room temperature, MPa; (2) Transverse section strength verification:

[0115] The transverse section is as follows Figure 8 Section CC shown.

[0116] Shear stress τ on section CC c-c :

[0117]

[0118] Maximum tensile stress σ on section CC c-c :

[0119]

[0120] Combined normal stresses σ3 and σ4 on section CC:

[0121]

[0122] According to the third strength theory, the section CC can meet the strength requirements if the following equation is true:

[0123] |σ3-σ4|≤0.9[σ s ]

[0124] Where: tr——the thickness of the support plate 4 in mm,

[0125] hr——the height of the support plate 4 in mm,

[0126] tc——Thickness of upper support ring 5 and lower support ring 6 in mm,

[0127] Le——Effective support range of upper support ring 5 and lower support ring 6 in mm,

[0128]

[0129] [σ s ]——Yield strength of support plate 4 material at room temperature, MPa,

[0130] tp——thickness of pad in mm;

[0131] wk——width of support plate in mm,

[0132] like Figure 5 There are only two upper and lower supports in the load-bearing structure, so the force on each support is 1 / 2*F support .

[0133] Example 2

[0134] A tower made of duplex steel S32205, with an inner diameter of 1100mm and a height of about 11m, with an upper wall thickness of 12mm and a lower wall thickness of 24mm; it is connected to the foundation with a skirt; the equipment has a design pressure of 0.75MPa and a design temperature of 180℃; the explosion pressure P dynamic =0.29 bar (gauge pressure), explosion wind load from the beginning to the end, t d =0.099s; yield strength σ of duplex steel S32205 at design temperature s =360MPa.

[0135] According to the support structure and design method proposed in the present invention, the structural dimensions are strength-checked to ensure that the support structure can withstand the explosion shock wave under the design working conditions.

[0136] Step 1: Use the pressure vessel strength calculation software to calculate the first-order natural frequency f of the tower under the design working condition = 8.79 Hz, and the natural vibration period T = 1 / f;

[0137] Step 2: Set the explosion wind pressure P dynamic Equivalent to static wind pressure P static ;

[0138] P static =P dynamic ×C D ×DLF=0.29×1×1.6=0.464brag

[0139] Among them, select DLF=1.6,

[0140] Step 3: Equivalent static wind pressure P static Substitute this into the model built in step 1 and calculate the equivalent static wind pressure thrust F1, F2, F3...F9 on each segment of the tower (segments 1 to 9, each segment has a length of h_1 to h_9).

[0141] Step 4: Calculate the linear load of each section: q1 = 55.3 N / mm, q2 = 63.7 N / mm, q3 = 20.3 N / mm, q4 = 71.7 N / mm, q5 = 71.7 N / mm, q6 = 70.4 N / mm, q7 = 113.1 N / mm, q8 = 70.4 N / mm, q9 = 13.2 N / mm.

[0142] Step 5: Bring q1, q2, q3...q9 in step 4 as line loads into the Ansys finite element software. The finite element model uses beam elements, and the constraints of the finite element model are applied according to Figure 6 As shown in the figure, the bottom nodes are fixed and the nodes at the supporting structure are hinged. The finite element model is established as follows Figure 6 shown.

[0143] Step 6: Extract the force F at the support structure support 、M support , F support =845420N.

[0144] Step 7: Cross-section verification of support structure

[0145] (1) Longitudinal section BB strength check:

[0146] Shear stress τ on longitudinal section BB b-b :

[0147]

[0148] Maximum tensile stress σ on longitudinal section BB b-b :

[0149]

[0150] Combined normal stresses σ1 and σ2 on longitudinal section BB:

[0151]

[0152] According to the third strength theory, the maximum Tresca stress on section BB should be less than 0.9*σ s =324MPa, which can meet the strength requirements. Obviously, the BB section can meet the strength requirements:

[0153] |σ1-σ2|=|248.3-(-12.8)|=261.1MPa≤324MPa

[0154] (2) Transverse section CC strength check:

[0155] Shear stress τ on section CC c-v :

[0156]

[0157] Maximum tensile stress σ on section CC c-c :

[0158]

[0159] Combined normal stresses σ3 and σ4 on section CC:

[0160]

[0161] σ4=-4.4MPa,

[0162] According to the third strength theory, the maximum Tresca stress on the CC section is less than 0.9*σ s , section CC can meet the strength requirements:

[0163] |σ3-σ4|=|181.2-(-4.4)|=185.6MPa≤0.9σ s =324MPa

[0164] The strength calculation of the comprehensive sections BB and CC has passed. Therefore, the supporting structure size of the tower to resist the explosion wind load is able to meet the explosion shock wave with a peak value of 0.29 bar and a period of 0.099s.

[0165] The series of detailed descriptions listed above are only specific descriptions of feasible implementation methods of the present invention. They are not intended to limit the scope of protection of the present invention. Any equivalent implementation methods or changes that do not deviate from the technical spirit of the present invention should be included in the scope of protection of the present invention.

[0166] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. A tower support structure resistant to explosion loads, characterized in that: It includes several pads connected to the tower cylinder, support plates connected to the pads, and upper and lower support rings connected to the tower cylinder; the upper and lower support rings are both connected to the pads and are respectively connected to the upper and lower ends of the support plates; Teflon plates are pasted on both sides of the support plate; The upper support ring and the tower cylinder, the backing plate and the support plate are all welded by fillet welds; The lower support ring and the tower cylinder, the backing plate and the support plate are all welded by fillet welds; The invention also comprises a caliper for clamping the support plate, wherein the Teflon plate enables the support plate and the caliper to slide freely relative to each other without friction.

2. The tower support structure resistant to explosion loads according to claim 1, characterized in that: The backing plate and the tower cylinder are welded by fillet welds.

3. The tower support structure resistant to explosion loads according to claim 1, characterized in that: The backing plate and the support plate are welded by full penetration welds.

4. The tower support structure resistant to explosion loads according to claim 1, characterized in that: The upper support ring and the lower support ring are both metal rings.

5. The tower support structure resistant to explosion loads according to claim 1, characterized in that: The support plate is a steel plate.

6. The tower support structure resistant to explosion loads according to claim 1, characterized in that: The pad is located at the middle height of the tower cylinder.

7. A method for designing a tower support structure resistant to explosion loads according to any one of claims 1 to 6, comprising the following steps: Step 1: Use pressure vessel strength calculation software to model the tower and calculate the first-order natural vibration period T of the tower under working conditions; Step 2: Set the explosion wind pressure P dynamic Equivalent to static wind pressure P static , P static =P dynamic ×C D ×DLF, in, P dynamic ——provided by design conditions, unit bar, C D ——Drag coefficient of explosion wind load, take 1, DLF - dynamic load factor, the value range of DLF is 0 to 2; Step 3: Substitute the equivalent static wind load P calculated in step 2 static Substitute the calculations from step 1 to calculate the explosion wind pressure thrusts F1, F2, F3...Fi on each segment of the tower (dividing the tower into several segments 1 to i, with each segment length h_i); Step 4: Calculate for each segment: q1 = F1 / h_1, q2 = F2 / h_2, q3 = F2 / h_3...qi = Fi / h_i, unit N / m; Step 5: Bring q1, q2, q3...qi in step 4 as line loads into the Ansys finite element software for calculation; Step 6: Extract the force F at the support structure calculated by finite element method support ; Step 7: Check the cross-sectional strength of the supporting structure.

8. The design method of the tower support structure resistant to explosion loads according to claim 7, characterized in that: In step 1, the pressure vessel strength calculation software is PV Elite software.

9. The design method of the tower support structure resistant to explosion loads according to claim 7, characterized in that: The numerical range of DLF in the step 2 is 0.5 to 1.

5.

10. The design method of a tower support structure resistant to explosion loads according to claim 9, characterized in that: In step 5, the finite element model adopts beam elements, the nodes of the support structure adopt hinged supports, the bottom nodes of the tower adopt fixed supports, and the constraints of the finite element model are as follows: (1) Support structure nodes: ux = 0, uy = 0, uz = 0, (2) Bottom node: ux=0, uy=0, uz=0, urx=0, ury=0, urz=0.

11. The design method of a tower support structure resistant to explosion loads according to claim 10, characterized in that: The cross-sectional strength check of the support structure in step seven is divided into: (1) Longitudinal section strength check: Shear stress τ on the longitudinal section b-b : Maximum tensile stress σ on the longitudinal section b-b : Combined normal stresses σ1 and σ2 on the longitudinal section: According to the third strength theory, the longitudinal section can meet the strength requirements by ensuring the following formula is true: |σ1-σ2|≤0.9[σ s ] Among them: tr——the thickness of the support plate in mm, hr——the height of the support plate in mm, wr——the width of the support plate that leaks out of the upper and lower support rings (mm), [σ s ]——yield strength of support plate material at room temperature, MPa; (2) Transverse section strength check: Shear stress τ on the transverse section c-c : Maximum tensile stress σ on the transverse section c-c : Combined normal stresses σ3 and σ4 on the transverse section: According to the third strength theory, the transverse section can meet the strength requirements by ensuring the following formula is true: |σ3-σ4|≤0.9[σ s ] Among them: tr——the thickness of the support plate in mm, hr——the height of the support plate in mm, tc——Thickness of upper support ring and lower support ring in mm, Le——Effective support range of upper support ring and lower support ring in mm, [σ s ]——Yield strength of support plate material at room temperature, MPa, tp——thickness of pad in mm; wk——width of support plate in mm.

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