A detachable support device and a strength calculation method thereof

Abstract

The application discloses a strength calculation method of a detachable support device, and the method comprises the following steps: acquiring the support force and the radial force per unit length of the detachable support device; calculating the bending moment and the horizontal tension at the connecting section according to the support force and the radial force per unit length; establishing the static moment balance equation of the connecting section, and determining the neutral axis position of the connecting section through iterative calculation; calculating the moment of inertia of the connecting section according to the neutral axis position; and calculating the maximum tensile stress borne by the fastener according to the moment of inertia, the bending moment and the horizontal tension, so as to check the strength of the connecting section. The application deduces the strength checking formula and the judgment basis of the key stress section in the detachable support structure, facilitates the engineering and technical personnel, and ensures the operation safety.

Description

Technical Field

[0001] This invention relates to the field of nuclear power equipment, and in particular to a detachable support device and its strength calculation method. Background Technology

[0002] In the field of pressure vessel and nuclear power equipment manufacturing, with the continuous improvement of equipment capabilities, equipment is becoming increasingly larger and heavier. During the manufacturing and transportation of this heavy equipment, support devices are typically needed for lifting, supporting, or repositioning. Traditional methods often rely on large cranes for hoisting, but this approach is frequently accompanied by high operating costs. Furthermore, in some equipment manufacturing scenarios, the space between the bottom of the heavy container and the foundation is very limited, making it difficult to directly place conventional large lifting devices at the bottom of the heavy container for operation.

[0003] To adapt to confined spaces and reduce reliance on large hoisting equipment, existing technologies employ saddle-type support structures with both ends as load-bearing support points to assist in equipment lifting. However, such support structures have significant limitations in practical applications: currently, relevant domestic and international standards and specifications lack strength calculation methods and verification systems for such support structure systems. During engineering design and operation, the lack of reliable theoretical calculations to assess the safety of critical load-bearing sections poses safety hazards during heavy container lifting operations.

[0004] The statements herein provide only background information in relation to this invention and do not necessarily constitute prior art. Summary of the Invention

[0005] The purpose of this invention is to provide a detachable support device and its strength calculation method to solve the problem of lack of systematic strength calculation for key stress sections in the support device. It has the advantages of strong universality and simple calculation.

[0006] To achieve the above objectives, the present invention provides a strength calculation method for a detachable support device used to support heavy containers. The detachable support device includes a first support portion and a second support portion that are detachably connected. The connection between the first and second support portions forms a connecting section composed of fasteners and a connecting plate. This connecting section, as one of the key load-bearing sections, experiences tensile force borne by the fasteners and compressive force borne by the connecting plate. The method includes: obtaining the supporting force and radial force per unit length of the detachable support device; calculating the bending moment and horizontal tensile force at the connecting section based on the supporting force and the radial force per unit length; establishing the static moment equilibrium equation of the connecting section and determining the neutral axis position of the connecting section through iterative calculation; calculating the moment of inertia of the connecting section based on the neutral axis position; and calculating the maximum tensile stress borne by the fasteners based on the moment of inertia, the bending moment, and the horizontal tensile force, thereby verifying the strength of the connecting section.

[0007] For example, the formula for calculating the bending moment at the connection section based on the supporting force and the radial force per unit length is:

[0008] ;

[0009] in, The total load of the detachable support device. The distance between the two fulcrums of the detachable support device is [missing information], and the radial force per unit length is [missing information]. , The angle between any point of contact between the detachable support device and the heavy container and the vertical axis of symmetry containing the center of the cross-section of the heavy container. Let be the angle between the vertical axis of symmetry containing the center of the cross-section of the heavy container and the initial point of contact. The radius of the heavy container.

[0010] For example, the formula for calculating the horizontal tensile force based on the supporting force and the radial force per unit length is:

[0011] ;

[0012] in, The total load of the detachable support device. The angle between the vertical axis of symmetry containing the center of the cross-section of the heavy container and the initial contact point.

[0013] For example, using the bottom edge of the connecting section as the horizontal reference axis x-axis, the step of determining the position of the neutral axis of the connecting section through iterative calculation includes: setting the initial position of the neutral axis; calculating the number of rows of tension fasteners located above the x-axis and below the neutral axis based on the initial position and the geometric dimensions of the connecting plate; determining whether the static moment balance equation is valid or less than or equal to a preset value based on the static moment balance equation; wherein, the preset value is equal to the product of the absolute value of the static moment of the metal material under compressive stress above the neutral axis about the neutral axis and 0.01; if it is not valid or greater than the preset value, then updating the position value of the neutral axis and the number of rows of tension fasteners located above the x-axis and below the neutral axis, and recalculating the static moment balance equation until the static moment balance equation is valid or less than or equal to the preset value, and outputting the current position of the neutral axis.

[0014] For example, the static moment balance equation is: static moment of the tensioned fastener below the x-axis about the neutral axis + static moment of the tensioned fastener above the x-axis and below the neutral axis about the neutral axis - static moment of the compressive stress metal material above the neutral axis about the neutral axis - static moment of the unstretched fastener above the neutral axis about the neutral axis = 0.

[0015] For example, if the connecting cross section has k columns and n rows of fasteners, the neutral axis is located at position y on the connecting cross section, and the neutral axis y is separated from the x-axis by m rows of fasteners, then the static moment equilibrium equation is:

[0016] ;

[0017] Where S is the area of ​​a single fastener. The height of the connecting plate. The width of the connecting plate is given. In the above formula, the first term is the static moment of the tensioned fastener located below the x-axis about the neutral axis. The second term is the static moment of the tensioned fastener located above the x-axis and below the neutral axis about the neutral axis. The third term is the static moment of the metal material under compressive stress above the neutral axis about the neutral axis. The fourth term is the static moment of the unstretched fastener above the neutral axis about the neutral axis.

[0018] For example, calculating the maximum tensile stress borne by the fastener includes: calculating the maximum tensile force on the single fastener furthest from the neutral axis under pure bending moment based on the moment of inertia and the bending moment, and dividing the maximum tensile force by the area of ​​the single fastener to obtain the bending tensile stress; dividing the horizontal tensile force by the total area of ​​all fasteners to obtain the tensile stress; and adding the bending tensile stress and the tensile stress to obtain the maximum tensile stress borne by the fastener; wherein the maximum tensile stress should not exceed the allowable stress of the fastener.

[0019] For example, the detachable support device further includes a first cross section with the smallest size, which serves as another key stress-bearing cross section. The method further includes: obtaining the shear force and bending moment subjected to the first cross section; calculating the shear stress and bending stress of the first cross section; calculating the shear stress and bending stress using the fourth strength theory to obtain a combined stress for strength verification of the first cross section; wherein the combined stress should not exceed the allowable stress of the material.

[0020] For example, the bending moment experienced by the first section is ,in, The total load of the detachable support device. The distance from the contact point between the heavy container and the detachable support device to the fulcrum; the shear force on the first cross section is... The shear stress of the first cross section is ,in, The area of ​​the first cross-section is ; the bending stress of the first cross-section is . ,in, Let be the section modulus of the first section; the combined stress is calculated using the fourth strength theory. .

[0021] The present invention also provides a detachable support device for supporting heavy containers, comprising: a first support portion and a second support portion that are detachably connected, wherein the connection between the first support portion and the second support portion forms a connection cross section composed of fasteners and a connecting plate; the strength of the fasteners and the connecting plate is verified by the strength calculation method described above.

[0022] Compared with the prior art, the detachable support device and its strength calculation method provided by the present invention have at least the following beneficial effects: The present invention derives the mathematical formula expression of the bending moment of the connecting section formed by the fastener and the connecting plate in the detachable support structure, and provides the strength verification formula and judgment basis of the key stress section (including the connecting section and the first section), which facilitates the majority of engineering technicians to quickly calculate the strength of the connecting section and the first section, and can quickly judge according to the judgment basis, thus ensuring the safety of operation. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the detachable support device according to an embodiment of the present invention;

[0024] Figures 2-4 This is a schematic diagram illustrating the use of the detachable support device according to an embodiment of the present invention;

[0025] Figure 5 This is a schematic diagram of the force analysis of the detachable support device according to an embodiment of the present invention;

[0026] Figure 6 This is a flowchart illustrating the strength calculation method for the detachable support device according to an embodiment of the present invention.

[0027] Figure 7 This is a schematic diagram of the force analysis of the connection section of the detachable support device according to an embodiment of the present invention;

[0028] Figure 8 This is a cross-sectional schematic diagram of the fastener-connecting plate of the detachable support device according to an embodiment of the present invention;

[0029] Figure 9 This is a schematic diagram of the iterative calculation process for the position of the sex axis in an embodiment of the present invention;

[0030] Figure 10 This is a schematic diagram of the force analysis of the first cross section of the detachable support device according to an embodiment of the present invention. Detailed Implementation

[0031] The detachable support device and its strength calculation method proposed in this invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. The advantages and features of this invention will become clearer from the following description. It should be noted that the drawings are in a very simplified form and use non-precise proportions, only for the purpose of conveniently and clearly illustrating the embodiments of this invention. Please refer to the drawings to make the objectives, features, and advantages of this invention more apparent and understandable. It should be understood that the structures, proportions, sizes, etc., depicted in the accompanying drawings are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed in the specification, and are not intended to limit the implementation conditions of this invention. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportional relationships, or adjustments to the size, without affecting the effects and objectives achieved by this invention, should still fall within the scope of the technical content disclosed in this invention.

[0032] To solve the problem of lifting and lowering heavy containers, such as Figure 1As shown, this embodiment of the invention provides a detachable support device 100, which is used to support heavy containers. Its overall structure is a saddle-type simply supported beam. The detachable support device 100 includes a first support part 101 and a second support part 102 that are detachably connected. The connection between the first support part 101 and the second support part 102 forms a connecting section 106, which is composed of fasteners 161 and connecting plates 162. In this embodiment, bolts and nuts are used as the fasteners 161. The bottoms of the first support part 101 and the second support part 102 are respectively provided with casters 105 to facilitate movement and position adjustment of the support device at the bottom of the heavy container, reducing reliance on on-site cranes and other lifting equipment, simplifying operation, and greatly improving installation efficiency. In actual operation, it is used in conjunction with a lifting mechanism 103 (such as a jack) and bottom sleepers 104. By placing the lifting mechanism 103 and sleepers 104 at designated positions on the first support part 101 and the second support part 102 respectively... Figure 1 As shown), the synchronous operation of the lifting mechanism 103 lifts the support device and heavy container to the predetermined height.

[0033] In this embodiment, the first support portion 101 and the second support portion 102 have the same structure and shape. This embodiment will take the first support portion 101 as an example for detailed description. The first support portion 101 includes a pad 111, which has an arc-shaped support surface and is in contact with the outer curved surface of the heavy container to support the heavy container; a cover plate 112, which is horizontally arranged at the top of the first support portion 101 and connected to the pad 111; a plurality of stiffening plates 113, which are vertically arranged below the cover plate 112, connecting the cover plate 112 and the bottom plate to form an integral load-bearing frame; and a plurality of web plates 114, which are arranged between the pad 111 and the bottom plate, connecting the pad 111 and the bottom plate to form an integral load-bearing frame. The web plates 114 are distributed along the length direction of the first support portion to form a plurality of reinforcing ribs to enhance the bending stiffness of the support device.

[0034] like Figures 2-4As shown, the working principle and usage process of the detachable support device 100 provided in this embodiment are as follows: First stage: Push the first support part 101 and the second support part 102, which are in a disassembled state, into the bottom of the heavy container 200 from both sides, and use the casters 105 at the bottom to move and adjust their position within the confined space; Second stage: Align the first support part 101 and the second support part 102, and use fasteners 161 and connecting plates 162 to fix them into a single load-bearing structure; Third stage: Place the lifting mechanism 103 (such as a jack) and sleepers 104 at designated positions on both sides of the detachable support device 100; Fourth stage: Simultaneously operate the lifting mechanism 103 to lift the detachable support device 100 and the heavy container 200 to a predetermined height. For lowering and dismantling, simply reverse the above four stages.

[0035] Based on the detachable support device 100 provided in the above embodiments, this invention also provides a method for calculating the strength of the detachable support device. On the one hand, this method can verify the strength of the detachable support device 100, thereby ensuring operational safety. On the other hand, this method can derive a mathematical formula for the bending moment of the connecting section 106 in the detachable support device 100, thereby facilitating engineers to quickly calculate the strength of the connecting section.

[0036] In practical use, a stress analysis is first performed on the detachable support device 100 to identify the key stress-bearing sections and components. The stress analysis of the detachable support device 100 is as follows: Figure 5 As shown, the detachable support device 100 can be considered as a simply supported beam with both ends simply supported. The cross-sectional dimensions of the beam are not fixed at each location. When the beam is subjected to... Figure 5 When the load is described, according to the general knowledge of mechanics of materials, the bending moment generated at section 2-2 (i.e. the connecting section) is the largest, while section 1-1 (i.e. the first section) has the smallest cross-sectional area and bending modulus of the beam. Therefore, sections 1-1 and 2-2 are the critical sections.

[0037] Based on the above stress analysis results, since section 2-2 (i.e., the connecting section) bears the maximum bending moment, and this section is composed of fasteners and connecting plates, its mechanical properties differ significantly from those of a homogeneous section. Therefore, a specific strength check must be performed on this connecting section. Furthermore, since the first and second support parts are detachably connected via fasteners and connecting plates, a physical gap exists between the connecting plates 162 at connecting section 106, preventing the transmission of tensile force. Therefore, the tensile force on connecting section 106 is entirely borne by the fasteners 161 penetrating the connecting plates 162; while under compression, the compressive force is borne by the connecting plates 162. To accurately check the bearing capacity of this connecting section, such as... Figure 6As shown, the strength calculation of the connection section in this embodiment of the invention includes the following steps:

[0038] S11. Obtain the supporting force and radial force per unit length of the detachable support device 100.

[0039] In some embodiments, the detachable support device 100 can be considered as a simply supported beam with both ends simply supported. The detachable support device 100 bears the total load Q transmitted by the heavy container 200. Force analysis shows that the supporting force borne by the connecting section 106 of the detachable support device 100 is Q / 2, and the radial force borne is... In the support force Q / 2 and radial force Under the combined effect of these forces, the bending moment is greatest at and near the connecting section 106. Additionally, the radial force... The horizontal component of the force generates a horizontal tensile force F at the connecting section 106, such as Figure 7 As shown. For example, the radial force per unit length. A radial force per unit length, proposed by scholar Zick, can be used. The representation is as follows:

[0040] (1)

[0041] Wherein, in equation (1) The total load of the support device. Let be the angle between any point of contact between the support device and the heavy container and the vertical axis of symmetry containing the center of the cross-section of the heavy container. Let be the angle between the vertical axis of symmetry containing the center of the cross-section of the heavy container and the initial point of contact. The radius of the heavy container.

[0042] S12. Calculate the bending moment and horizontal tension at the connecting section 106 based on the supporting force and the radial force per unit length.

[0043] In some embodiments, the formula for calculating the bending moment at the connection section based on the supporting force and the radial force per unit length is as follows:

[0044] (2)

[0045] Among them, in equation (2) The total load of the support device. The distance between the two support points of the support device. Let be the angle between any point of contact between the support device and the heavy container and the vertical axis of symmetry containing the center of the cross-section of the heavy container. Let be the angle between the vertical axis of symmetry containing the center of the cross-section of the heavy container and the initial contact point, and , The total contact angle between the support device and the heavy container. The radius of the heavy container.

[0046] It should be noted that, although radial force The horizontal component of the force also generates a bending moment at the connecting section 106 (i.e., section 2-2), but the direction of this bending moment is opposite to the direction of the bending moment of the supporting force Q / at the connecting section 106. Due to the conservative principles of engineering design, the radial force is neglected in the above equation (2). The horizontal component generates a counteracting bending moment at the connecting section 106.

[0047] Furthermore, based on the supporting force and the radial force per unit length, the formula for calculating the horizontal tensile force is as follows:

[0048] (3)

[0049] Among them, in equation (3) The total load of the support device. Let be the angle between any point of contact between the support device and the heavy container and the vertical axis of symmetry containing the center of the cross-section of the heavy container. Let be the angle between the vertical axis of symmetry of the center of the cross-section of the heavy container and the initial contact point. Based on the above equations (2) and (3), the bending moment and horizontal tension at the connecting section 106 can be calculated.

[0050] S13. Establish the static moment equilibrium equation of the connecting section 106, and determine the position of the neutral axis of the connecting section 106 through iterative calculation.

[0051] In some embodiments, since the tensile force in the connecting section 106 is borne only by the fastener 161 and the compressive force by the connecting plate 162, this section is a heterogeneous section with inconsistent tensile and compressive moduli. Its neutral axis no longer coincides with the geometric center axis of the section, but is biased towards the compression side. To solve for the neutral axis, as... Figure 8 As shown, the static moment equilibrium equation is established with the bottom edge of the connecting section 106 as the horizontal reference axis x-axis.

[0052] Under pure bending, the connecting section 106 has no axial force. According to general knowledge of mechanics of materials, we know that:

[0053] (4)

[0054] In the above formula (4), A refers to the cross section of the beam. Formula (4) represents the surface integral of a cross section.

[0055] Furthermore, based on the general assumption of bending stress in mechanics of materials, there is no normal stress between the "longitudinal fibers" within the beam, and it is under uniaxial stress. Therefore, at the connecting section 106:

[0056] (5)

[0057] In the above formula (5) The distance from a point in the cross section to the central axis is called the static moment in mechanics of materials. The left side of equation (5) is called the static moment.

[0058] Based on the above mechanical condition that there is no axial force on the cross section during pure bending, the static moment equilibrium equation is derived as follows:

[0059] The static moment of the tensioned fasteners below the x-axis about the neutral axis + the static moment of the tensioned fasteners above the x-axis and below the neutral axis about the neutral axis - the static moment of the compressive stress metal material above the neutral axis about the neutral axis - the static moment of the untensioned fasteners above the neutral axis about the neutral axis = 0

[0060] In a specific embodiment, if the connecting section 106 is provided with k columns and n rows of fasteners 161, the position of the neutral axis on the connecting section is y, and the neutral axis y and the x-axis include m rows of fasteners, then the static moment equilibrium equation is expressed as:

[0061] (6)

[0062] in, Figure 8 The embodiment shown has two rows of fasteners, namely S is the area of ​​a single fastener. The height of the connecting plate is 162. The width of the connecting plate 162 is given by the following formula (6): the first term is the static moment of the tensioned fastener located below the x-axis about the neutral axis; the second term is the static moment of the tensioned fastener located above the x-axis and below the neutral axis about the neutral axis; the third term is the static moment of the metal material under compressive stress above the neutral axis about the neutral axis; and the fourth term is the static moment of the unstretched fastener above the neutral axis about the neutral axis.

[0063] Equation (6) above includes two unknown variables: the number of fastener rows m between the neutral axis y and the x-axis, and the position y of the neutral axis. y and m are related, depending on the geometric dimensions (height) of the connecting plate 106. and width The values ​​of y and m can be obtained through iterative calculation. Once the value of y is determined, the position of the neutral axis can be determined. In some embodiments, such as... Figure 9As shown, determining the position of the neutral axis of the connecting section through iterative calculation includes:

[0064] Set the initial position of the neutral axis y, and calculate the number m of the tension fasteners located above the x-axis and below the neutral axis based on the initial position and the geometric dimensions of the connecting plate;

[0065] Based on the static moment equilibrium equation, the initial position of the central axis y and the row number m are substituted into the static moment equilibrium equation (i.e., equation (6)), and it is determined whether the static moment equilibrium equation is valid or less than or equal to a preset value; wherein, the preset value is equal to the absolute value of the static moment of the metal material under compressive stress above the neutral axis about the neutral axis ( Figure 9 The product of S3 and 0.01;

[0066] If the result is not true (i.e., the result calculated on the left side of equation (6) is not equal to 0) or is greater than the preset value (i.e., the result calculated on the left side of equation (6) is greater than the preset value), then update the position value of the neutral axis y, and update the number m of the tensile fasteners located above the x-axis and below the neutral axis accordingly. Recalculate the static moment balance equation until the static moment balance equation is true (i.e., the result calculated on the left side of equation (6) is equal to 0) or is less than or equal to the preset value (i.e., the result calculated on the left side of equation (6) is less than or equal to the preset value), and output the current position of the neutral axis, and the iteration terminates.

[0067] S14. Calculate the moment of inertia of the connecting section based on the position of the neutral axis.

[0068] In some embodiments, after determining the neutral axis position y, the moments of inertia of the tension fastener region and the compression connecting plate region about the neutral axis are calculated respectively, and the two are added together to obtain the moment of inertia I of the connecting section 106 composed of the fastener 161 and the connecting plate 162.

[0069] S15. Calculate the maximum tensile stress borne by the fastener based on the moment of inertia I, the bending moment M2, and the horizontal tensile force F, so as to perform strength verification on the connection section.

[0070] In some embodiments, the maximum tensile stress borne by the fastener 161 is formed by the superposition of two parts: the first part is the bending tensile stress under pure bending moment, and the second part is the tensile tensile stress under horizontal tension. The calculation of the bending tensile stress includes, based on the moment of inertia I and the bending moment M2, calculating the stress at the point farthest from the neutral axis (i.e., at a distance y) under pure bending moment. max The bending tensile stress is obtained by dividing the maximum tensile force on a single fastener by the area of ​​the single fastener. The calculation expression is as follows:

[0071] (7)

[0072] Among them, in equation (7) This represents the farthest distance of the tensioned fastener from the neutral axis y.

[0073] In some embodiments, the calculation of the tensile stress includes dividing the horizontal tensile force F by the total area A of all fasteners. total The tensile stress is obtained, and the calculation expression is as follows:

[0074] (8)

[0075] Among them, in equation (8) This represents the total area of ​​the fastener.

[0076] Adding equation (7) for bending tensile stress to equation (8) for tensile stress, we obtain the maximum tensile stress that the fastener can withstand. The calculation expression is as follows:

[0077]

[0078] In the strength verification process, the maximum tensile stress is... The maximum tensile stress should not exceed the allowable stress of the fastener. If the maximum tensile stress exceeds the allowable stress, the fastener is at risk of plastic deformation or fracture.

[0079] Furthermore, in this embodiment, the first cross-section (i.e., surface 1-1) is also a critical cross-section. Due to the abrupt change in cross-sectional dimensions at this location, strength verification is also required. The strength calculation for this first cross-section (i.e., surface 1-1) includes the following steps:

[0080] S21. Obtain the shear force and bending moment acting on the first cross section;

[0081] In some embodiments, the first section is subjected to shear force and bending moment generated by the supporting force Q / 2, such as Figure 10 As shown, the bending moment experienced by the first cross section and shear force The expression is as follows:

[0082] (9)

[0083] (10)

[0084] Among them, in equation (9) The total load of the support device. This is the distance from the contact point between the heavy container and the support device to the fulcrum.

[0085] S22. Calculate the shear stress and bending stress of the first cross section;

[0086] In some embodiments, the shear stress of the first cross section and bending stress The expression is as follows:

[0087] (11)

[0088] (12)

[0089] Wherein, in equation (11) The area of ​​the first cross section; in equation (12) Let be the section modulus of the first section. The section modulus of the bending of any section can be calculated using general knowledge of mechanics of materials.

[0090] S23. The shear stress and bending stress are calculated using the fourth strength theory to obtain the combined stress for strength verification of the first section.

[0091] In some embodiments, the fourth strength theory is used to assess the shear stress. and the bending stress The expression used for calculation is:

[0092] (13)

[0093] The combined stress of the first section can be calculated according to equation (13). The strength of the first section is checked based on the combined stress. The judgment basis for the check is the combined stress. The stress should not exceed the allowable stress of the support material. If the combined stress exceeds the allowable stress of the support material, the first section is at risk of plastic deformation or fracture.

[0094] It should be noted that the strength verification of the remaining stiffening plates 111 and cover plates 112 in the detachable support device 100 can be completed by referring to the relevant calculation formulas for saddles and lug supports in standard NB / T47065. This embodiment of the invention will not elaborate on these details.

[0095] This invention accurately determines the offset position of the neutral axis by establishing a static moment equilibrium equation and introducing an iterative algorithm based on a static moment error threshold of 0.01 times for compressed metal materials. This calculation logic avoids errors in the calculation of the moment of inertia of the connecting sections, thereby preventing fastener fracture failure due to actual stress exceeding the design value. Simultaneously, in the bending moment calculation of the connecting sections, by identifying and ignoring the counteracting bending moment generated by the horizontal component of the radial force, the calculation results are biased towards the safe side (conservative design), simplifying the integral calculation process while improving the safety redundancy of the engineering design. Furthermore, the shear force and bending moment of the first section are combined and checked using the fourth strength theory, conforming to the yield failure criterion of the first section under complex stress states, thus overcoming the limitations of traditional methods that simply check normal stress or shear stress.

[0096] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0097] In the description of this invention, it should be understood that the terms "center," "height," "thickness," "upper," "lower," "vertical," "horizontal," "top," "bottom," "inner," "outer," "axial," "radial," and "circumferential," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0098] In the description of this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0099] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0100] Although the present invention has been described in detail through the preferred embodiments above, it should be understood that the above description should not be considered as a limitation of the present invention. Various modifications and substitutions to the present invention will be apparent to those skilled in the art after reading the above description. Therefore, the scope of protection of the present invention should be defined by the appended claims.

Claims

1. A method for calculating the strength of a detachable support device, the detachable support device being used to support a heavy container, comprising a detachably connected first support portion and a second support portion, wherein the connection between the first support portion and the second support portion forms a connection cross-section composed of fasteners and a connecting plate, the connection cross-section being one of the key stress-bearing cross-sections, wherein the tensile force on it is borne by the fasteners and the compressive force is borne by the connecting plate; characterized in that, The method includes: Obtain the supporting force and radial force per unit length of the detachable support device; Calculate the bending moment and horizontal tension at the connection section based on the supporting force and the radial force per unit length; Establish the static moment equilibrium equation of the connecting section, and determine the position of the neutral axis of the connecting section through iterative calculation; Calculate the moment of inertia of the connecting section based on the position of the neutral axis; The maximum tensile stress borne by the fastener is calculated based on the moment of inertia, the bending moment, and the horizontal tensile force, so as to verify the strength of the connection section.

2. The strength calculation method for the detachable support device as described in claim 1, characterized in that, Based on the supporting force and the radial force per unit length, the formula for calculating the bending moment at the connection section is as follows: ； in, The total load of the detachable support device. The distance between the two fulcrums of the detachable support device is [missing information], and the radial force per unit length is [missing information]. , The angle between any point of contact between the detachable support device and the heavy container and the vertical axis of symmetry containing the center of the cross-section of the heavy container. Let be the angle between the vertical axis of symmetry containing the center of the cross-section of the heavy container and the initial point of contact. The radius of the heavy container.

3. The strength calculation method for the detachable support device as described in claim 2, characterized in that, Based on the supporting force and the radial force per unit length, the formula for calculating the horizontal tensile force is as follows: ； in, The total load of the detachable support device. The angle between the vertical axis of symmetry containing the center of the cross-section of the heavy container and the initial contact point.

4. The strength calculation method for the detachable support device as described in claim 1, characterized in that, Using the bottom edge of the connecting section as the horizontal reference axis x-axis, the step of determining the position of the neutral axis of the connecting section through iterative calculation includes: Set the initial position of the neutral axis, and calculate the number of rows of tension fasteners located above the x-axis and below the neutral axis based on the initial position and the geometry of the connecting plate; Based on the static moment equilibrium equation, determine whether the static moment equilibrium equation is valid or less than or equal to a preset value; wherein, the preset value is equal to the product of the absolute value of the static moment of the metal material under compressive stress above the neutral axis about the neutral axis and 0.01; If the condition is not met or is greater than the preset value, then update the position value of the neutral axis and the number of rows of tension fasteners located above the x-axis and below the neutral axis, and recalculate the static moment balance equation until the static moment balance equation is met or less than or equal to the preset value, and output the current position of the neutral axis.

5. The strength calculation method for the detachable support device as described in claim 4, characterized in that, The static moment equilibrium equation is as follows: The static moment of the tensioned fasteners below the x-axis about the neutral axis + the static moment of the tensioned fasteners above the x-axis and below the neutral axis about the neutral axis - the static moment of the compressive stress metal material above the neutral axis about the neutral axis - the static moment of the untensioned fasteners above the neutral axis about the neutral axis = 0.

6. The strength calculation method for the detachable support device as described in claim 5, characterized in that, If the connecting cross section has k columns and n rows of fasteners, and the neutral axis is located at position y on the connecting cross section, and the neutral axis y is separated from the x-axis by m rows of fasteners, then the static moment equilibrium equation is: ； Where S is the area of ​​a single fastener. The height of the connecting plate. The width of the connecting plate is given. In the above formula, the first term is the static moment of the tensioned fastener located below the x-axis about the neutral axis. The second term is the static moment of the tensioned fastener located above the x-axis and below the neutral axis about the neutral axis. The third term is the static moment of the metal material under compressive stress above the neutral axis about the neutral axis. The fourth term is the static moment of the unstretched fastener above the neutral axis about the neutral axis.

7. The strength calculation method for the detachable support device as described in claim 1, characterized in that, Calculating the maximum tensile stress that the fastener can withstand includes: Based on the moment of inertia and the bending moment, calculate the maximum tensile force on the single fastener furthest from the neutral axis under pure bending moment, and divide the maximum tensile force by the area of ​​the single fastener to obtain the bending tensile stress. Divide the horizontal tensile force by the total area of ​​all fasteners to obtain the tensile stress. The bending tensile stress is added to the tensile tensile stress to obtain the maximum tensile stress that the fastener can withstand; wherein the maximum tensile stress should not exceed the allowable stress of the fastener.

8. The strength calculation method for the detachable support device as described in claim 1, characterized in that, The detachable support device further includes a first cross-section with the smallest dimension, which serves as another key stress-bearing cross-section. The method further includes: Obtain the shear force and bending moment acting on the first cross section; Calculate the shear stress and bending stress of the first cross section; The shear stress and bending stress are calculated using the fourth strength theory to obtain the combined stress for strength verification of the first section; wherein the combined stress should not exceed the allowable stress of the material.

9. The strength calculation method for the detachable support device as described in claim 8, characterized in that, The bending moment experienced by the first section is ,in, The total load of the detachable support device. The distance from the contact point between the heavy container and the detachable support device to the fulcrum; The shear force on the first section is ; The shear stress of the first cross section is ,in, The area of ​​the first cross section; The bending stress of the first section is ,in, The section modulus of the first section is flexural strength. The combined stress is calculated using the fourth strength theory. .

10. A detachable support device for supporting heavy containers, characterized in that, include: A detachably connected first support portion and second support portion, wherein the connection between the first support portion and the second support portion forms a connection cross section composed of fasteners and a connecting plate; The strength of the fastener and the connecting plate is verified by the strength calculation method as described in any one of claims 1 to 9.

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