Method and device for identifying surface internal stress of unidirectional tension metal sheet

Abstract

The invention provides a method and a device for identifying surface internal stress of a unidirectional tension metal sheet. The identification method comprises the following steps: monitoring the mode of the unidirectional tension metal sheet in real time, and obtaining the vibration frequency of the unidirectional tension metal sheet; establishing a free vibration differential equation of the unidirectional tension metal sheet on the basis of a Kirkhoff plate-shell theory; representing a general solution of a free oscillatory differential equation of the unidirectional tension metal sheet based on the situation that two opposite sides of the unidirectional tension metal sheet are simply supported and tensioned and the other two opposite sides are randomly supported; based on a free vibration differential equation of the unidirectional tension metal sheet and a general solution of the equation, establishing a frequency equation of the unidirectional tension metal sheet; and based on the vibration frequency of the unidirectional tension metal sheet, the uniform tension acting on the plate edge of the unidirectional tension metal sheet is calculated through a frequency equation. According to the method, the differential equation can be established based on the modal of the one-way tension metal sheet according to the CokylHough plate shell theory, and the surface internal stress state of the metal sheet is identified, so that the evaluation of the performance of the one-way tension metal sheet is realized.

Description

Technical Field

[0001] The invention relates to the technical field of nondestructive detection of in-plane stress of metal thin plates, and in particular to a method and a device for identifying in-plane stress of a unidirectionally tensile metal thin plate. Background Art

[0002] The tensioned metal sheet system has shown broad application prospects in many fields such as architecture, decoration, and engineering structures due to its significant advantages such as high strength, good durability, strong aesthetics, strong flexibility, and energy saving and environmental protection. Tensed metal sheets can meet the needs of different shapes, sizes, and structures, while reducing energy consumption and meeting the requirements of environmental protection and sustainable development. Tensed metal sheets can only exert their excellent working performance when they achieve the desired tensioning effect. The in-plane stress can reflect whether the tensioned metal sheet has achieved the desired tensioning effect. Therefore, accurately grasping the in-plane stress of unidirectional tensioned metal sheets is crucial to the design and use of structures.

[0003] Currently, the existing technology has proposed many non-destructive testing methods, but there is still a lack of methods for identifying in-plane stress of metal sheets under unidirectional tension. Summary of the invention

[0004] In view of the shortcomings of the prior art, the present invention proposes a method and device for identifying in-plane stress of a unidirectional tensioned metal sheet. Based on the modal data of the unidirectional tensioned metal sheet, the stress state of the metal sheet is identified, providing a simple and practical non-destructive testing method for performance evaluation of the unidirectional tensioned metal sheet.

[0005] To achieve the above objectives, the present invention is implemented through the following technical solutions:

[0006] A first aspect of the present invention provides a method for identifying in-plane stress of a unidirectional tensioned metal sheet, comprising:

[0007] Real-time monitoring of the mode of a unidirectional tensioned metal sheet to obtain the vibration frequency of the unidirectional tensioned metal sheet, wherein two pairs of edges of the unidirectional tensioned metal sheet are simply supported and tensioned, and the other two pairs of edges are arbitrarily supported;

[0008] Based on Keurgehof plate and shell theory, the free vibration differential equation of unidirectional tension metal plate is established;

[0009] The general solution of the differential equation for free vibration of a unidirectional tension metal plate is presented based on the case where two pairs of edges of the unidirectional tension metal plate are simply supported and tensioned and the other two pairs of edges are arbitrarily supported.

[0010] Based on the free vibration differential equation of the unidirectional tension metal sheet and the general solution of the equation, the frequency equation of the unidirectional tension metal sheet is established;

[0011] Based on the vibration frequency of the unidirectional tension metal sheet, the uniform tension acting on the edge of the unidirectional tension metal sheet is calculated by the frequency equation, so as to realize the stress identification of the tension at both ends of the unidirectional tension metal sheet.

[0012] In some achievable embodiments, the real-time monitoring of the mode of the unidirectional tension metal sheet and obtaining the vibration frequency of the unidirectional tension metal sheet are specifically:

[0013] Sensors are arranged on the unidirectional tension metal sheet to monitor the mode of the unidirectional tension metal sheet in real time to obtain the vibration frequency of the unidirectional tension metal sheet.

[0014] In some achievable embodiments, the free vibration differential equation of the unidirectional tension metal sheet is established as formula (1):

[0015]

[0016] Where: is the mass per unit area of ​​the metal sheet, D is the bending stiffness of the metal sheet, N x is the uniform tension acting on the edge of the metal plate, w(x,y,t) is the deflection of the metal plate when it vibrates, x is the lateral displacement, y is the longitudinal displacement, and t is the time.

[0017] In some achievable embodiments, the bending stiffness D of the metal sheet is calculated by the following formula:

[0018]

[0019] Where: E is the elastic modulus of the metal sheet, μ is the Poisson's ratio, and h is the thickness of the metal sheet.

[0020] In some achievable embodiments, the general solution of the differential equation characterizing the free vibration of the unidirectional tension metal sheet is as follows:

[0021]

[0022] Where: W j (x, y) is the vibration mode function of the metal plate, T j (t) is the time-dependent amplitude function, Y j (y) represents the jth mode shape function along the y direction, and a is the length of the plate.

[0023] In some achievable embodiments, the frequency equation of the unidirectional tension metal sheet is established based on the free vibration differential equation of the unidirectional tension metal sheet and the general solution of the equation as follows:

[0024] Substituting formula (2) into formula (1) and separating the variables, we can obtain the frequency equation of the unidirectional tension metal sheet, as shown in formula (3):

[0025]

[0026] Where: Y″(y) is the second-order derivative of Y.

[0027] In some achievable embodiments, based on the obtained vibration frequency of the unidirectional tension metal sheet, the uniform tension N acting on the edge of the unidirectional tension metal sheet is calculated using the following formula (4): x :

[0028]

[0029] Where: j is the jth vibration frequency of the metal plate under unidirectional tension.

[0030] A second aspect of the present invention provides an in-plane stress identification device for a unidirectional tensioned metal sheet, comprising:

[0031] A vibration frequency monitoring module is configured to monitor the mode of a unidirectional tension metal sheet in real time to obtain the vibration frequency of the unidirectional tension metal sheet, wherein two pairs of edges of the unidirectional tension metal sheet are simply supported and tensioned, and the other two pairs of edges are arbitrarily supported;

[0032] A free vibration differential equation building module is configured to build a free vibration differential equation of a unidirectional tension metal sheet based on Keuchhof plate and shell theory;

[0033] A free vibration differential equation general solution characterization module is configured to characterize a general solution of a free vibration differential equation of a unidirectional tension metal plate based on a case where two pairs of edges of the unidirectional tension metal plate are simply supported and tensioned and the other two pairs of edges are arbitrarily supported;

[0034] A frequency equation establishing module is configured to establish a frequency equation of the unidirectional tension metal sheet based on a free vibration differential equation of the unidirectional tension metal sheet and a general solution of the equation;

[0035] The calculation module is configured to calculate the uniform tension acting on the edge of the unidirectional tension metal plate based on the vibration frequency of the unidirectional tension metal plate by a frequency equation, thereby realizing stress identification of the tension at both ends of the unidirectional tension metal plate.

[0036] A third aspect of the present invention provides an electronic device, the device comprising:

[0037] one or more processors; and

[0038] A storage device is used to store one or more programs. When the one or more programs are executed by the one or more processors, the one or more processors implement the method described in the first aspect of the present invention.

[0039] A computer-readable storage medium stores a computer program, which, when executed by a processor, implements the method described in the first aspect of the present invention.

[0040] The beneficial effect of the present invention over the prior art is that the method and device for identifying in-plane stress of a unidirectional tensioned metal sheet provided by the present invention can identify the in-plane stress state of the metal sheet based on the mode of the unidirectional tensioned metal sheet, thereby realizing the evaluation of the performance of the unidirectional tensioned metal sheet. The specific advantages include at least one or more of the following:

[0041] (1) The stress identification method proposed in the present invention can obtain the mode of the metal thin plate in real time and monitor the vibration frequency of the metal thin plate in a timely manner by arranging sensors on the metal thin plate.

[0042] (2) The stress identification method proposed in the present invention is based on Keuchoff plate and shell theory and ignores the influence of shear deformation of metal sheets, which brings great convenience to engineering calculations and theoretical research. It is suitable for thin plate and shell structure analysis and is consistent with the performance evaluation of metal sheets in the present invention.

[0043] (3) The stress identification method proposed in the present invention realizes the identification of the in-plane stress state of the metal thin plate by establishing a small deflection bending model of the isotropic thin plate and performing non-destructive testing.

[0044] It should be understood that the implementation of any embodiment of the present invention does not mean that multiple or all of the above-mentioned beneficial effects must be possessed or achieved at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] In order to more clearly illustrate the implementation methods of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for the implementation methods or the description of the prior art. Obviously, the drawings in the following description are only exemplary, and for ordinary technicians in this field, other implementation drawings can be derived from the provided drawings without creative work.

[0046] The structures, proportions, sizes, etc. illustrated in this specification are only used to match the contents disclosed in the specification so as to facilitate understanding and reading by persons familiar with the technology. They are not used to limit the conditions under which the present invention can be implemented, and therefore have no substantial technical significance. Any structural modification, change in proportion or adjustment in size shall still fall within the scope of the technical contents disclosed in the present invention without affecting the effects and purposes that can be achieved by the present invention.

[0047] Figure 1 The overall process diagram of the method for identifying in-plane stress of a unidirectional tensioned metal sheet of the present invention is exemplarily shown;

[0048] Figure 2A schematic diagram of the force of a unidirectional tensioned metal sheet is shown as an example;

[0049] Figure 3 A schematic block diagram of a device for identifying in-plane stress of a unidirectional tensioned metal sheet according to the present invention is exemplarily shown;

[0050] Figure 4 A schematic block diagram exemplarily showing an electronic device provided by the present invention; and

[0051] Figure 5 A schematic block diagram of a computing device provided by the present invention is exemplarily shown.

[0052] In the various drawings, the same or corresponding reference numerals represent the same or corresponding parts. DETAILED DESCRIPTION

[0053] In order to make the purpose, technical solution and advantages of the embodiments of the present invention more clearly understood, the embodiments of the present invention are further described in detail below in conjunction with the embodiments and drawings. Here, the illustrative embodiments of the present invention and their description are used to explain the present invention, but are not intended to limit the present invention.

[0054] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0055] It should be understood that the terms "include / comprise", "consist of..." or any other variations are intended to cover non-exclusive inclusion, so that a product, device, process or method that includes a series of elements includes not only those elements, but also may include other elements not explicitly listed when necessary, or also includes elements inherent to such product, device, process or method. In the absence of more restrictions, the elements defined by the sentence "include / comprise...", "consist of..." do not exclude the presence of other identical elements in the product, device, process or method that includes the elements.

[0056] It is also necessary to understand that terms such as "upper", "lower", "front", "back", "left", "right", "top", "bottom", "inside" and "outside" to indicate directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device, component or structure must have a specific direction, be constructed or operate in a specific direction, and should not be understood as a limitation on the present invention.

[0057] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0058] In view of the fact that there is no method for identifying in-plane stress of unidirectionally tensioned metal sheets in the prior art, the present invention proposes a simple and effective in-plane stress identification method, which identifies the stress state of the metal sheet based on the modal data of the unidirectionally tensioned metal sheet. The method can be applied to the performance evaluation of the unidirectionally tensioned metal sheet, and is simple and practical.

[0059] In order to better understand the above technical solution, the above technical solution will be described in detail below with reference to the accompanying drawings and specific implementation methods.

[0060] The present invention provides a method 100 for identifying in-plane stress of a unidirectionally tensioned metal sheet. Figure 1 The flowchart shown specifically includes the following steps: 101, real-time monitoring of the mode of the unidirectional tension metal sheet, obtaining the vibration frequency of the unidirectional tension metal sheet, wherein two pairs of sides of the unidirectional tension metal sheet are simply supported and tensioned, and the other two pairs of sides are arbitrarily supported; 103, based on the Keuchoff plate and shell theory, establishing the free vibration differential equation of the unidirectional tension metal sheet; 105, based on the situation that two pairs of sides of the unidirectional tension metal sheet are simply supported and tensioned and the other two pairs of sides are arbitrarily supported, characterizing the general solution of the free vibration differential equation of the unidirectional tension metal sheet; 107, based on the free vibration differential equation of the unidirectional tension metal sheet and the general solution of the equation, establishing the frequency equation of the unidirectional tension metal sheet; 109, based on the vibration frequency of the unidirectional tension metal sheet, obtaining the uniform tension acting on the edge of the unidirectional tension metal sheet from the frequency equation, and realizing the stress identification of the tension at both ends of the unidirectional tension metal sheet. The stress identification method provided by the present invention can be based on the mode of the unidirectional tension metal sheet and establish a differential equation according to the Keuchoff plate and shell theory to identify the stress state in the surface of the metal sheet, thereby realizing the evaluation of the performance of the unidirectional tension metal sheet.

[0061] The method steps of the present invention are introduced below with a specific embodiment.

[0062] like Figure 2 As shown in the figure, the unidirectional tension metal sheet studied in the present invention is a thin plate shell. In the plane coordinate system, O is the origin of the metal sheet, a is the length of the metal sheet, b is the width of the metal sheet, and the metal sheet is subjected to a tensile force N at both ends of the plate edge. x The tension can be regarded as uniform tension. When a thin plate is subjected to stress, its deflection is much smaller than the plate thickness, and it also satisfies certain basic assumptions, such as Keuchhof plate and shell theory. The thin plate and shell theory plays a guiding role in various engineering designs. The method of the present invention uses the classical thin plate and shell theory to realize the identification of in-plane stress of a unidirectionally tensioned metal thin plate.

[0063] In block 101 , the mode of the unidirectional tension metal sheet is monitored in real time, and the vibration frequency of the unidirectional tension metal sheet is obtained to serve as a characteristic parameter for subsequent calculation.

[0064] It should be noted that mode is an inherent vibration characteristic of a vibration system, generally including frequency, vibration shape, and damping.

[0065] The modal monitoring is carried out by arranging sensors on the metal sheet and monitoring in real time through the frequency monitoring equipment to obtain the modal data of the unidirectional tension metal sheet and obtain the vibration frequency in the mode of the unidirectional tension metal sheet as the characteristic parameter.

[0066] In block 103, based on the Keurgehof plate and shell theory, a free vibration differential equation of a unidirectional tension metal sheet is established.

[0067] It should be noted that Keuchhof's plate and shell theory ignores the influence of shear deformation and is often applicable to the analysis of thin plate and shell structures. Shear deformation refers to the fact that when an object is subjected to a pair of equal, opposite, parallel and close external forces, the cross section between the two forces on the object will shift relative to each other along the direction of the force. For the field of thin metal plates, the influence of shear deformation can be ignored.

[0068] When dealing with thin plate and shell structures, Keurgehof thin plate and shell theory can significantly simplify the calculation process, effectively reduce the amount of calculation and maintain high accuracy.

[0069] Keurgehov's plate and shell theory has three basic assumptions:

[0070] (1) The layers parallel to the mid-plane of the shell do not squeeze each other;

[0071] (2) Straight normal assumption: the straight line segment perpendicular to the mid-surface before deformation remains straight and perpendicular to the mid-surface after deformation, which is equivalent to ignoring the transverse shear deformation;

[0072] (3) There is no displacement parallel to the mid-plane.

[0073] Based on the above assumptions, it can be understood that the straight line element on the plate is initially perpendicular to the mid-plane, and after deformation, it is still perpendicular to the deformed mid-plane, and all fibers on the mid-plane are inextensible. From this, it can be obtained that the theory derives the approximate mathematical theory of thin deformable bodies. If the linear dimensions and cross-sectional dimensions of any part of the thin plate are of the same order of magnitude, then the general elastic mechanics equations are applicable to any tiny part of it.

[0074] In elastic mechanics, the vibration of a thin plate is mainly described by its deflection, that is, the displacement perpendicular to the mid-plane. For the case of undamped free vibration, the free vibration differential equation of a unidirectional tensioned metal plate can be expressed as a fourth-order partial differential equation, as shown in formula (1):

[0075]

[0076] Where: is the mass per unit area of ​​the metal sheet, D is the bending stiffness of the metal sheet, N x is the uniform tension acting on the edge of the metal plate, is the unknown quantity, that is, the term to be determined, w(x, y, t) is the deflection of the metal plate when it vibrates, x is the lateral displacement, y is the longitudinal displacement, and t is the time.

[0077] It should be noted that the deflection of a metal sheet during vibration is an important variable in the differential equation and is affected by many factors, including material properties, external force, vibration frequency, boundary conditions, etc. Deflection refers to the vertical distance that each point on the surface of a metal sheet deviates from the original plane after being acted upon by an external force. In vibration problems, the deflection changes with time and is an important parameter for describing the dynamic response of the sheet. There are many factors that affect the deflection, mainly including:

[0078] (1) Material properties: The material properties of metal sheets, such as elastic modulus, density, Poisson's ratio, etc., directly affect their deflection during vibration. The larger the elastic modulus, the stronger the ability of the sheet to resist deformation and the smaller the deflection.

[0079] (2) External force: The external force acting on the metal sheet is the direct factor that determines its deflection. The greater the external force, the greater the deflection of the sheet.

[0080] (3) Vibration frequency: The vibration frequency of a metal sheet is closely related to its deflection. In free vibration, the sheet vibrates at a certain natural frequency, and the deflection changes periodically over time. In forced vibration, when the external excitation frequency is close to the natural frequency of the sheet, resonance occurs, and the deflection increases significantly.

[0081] (4) Boundary conditions: The boundary conditions of metal sheets have an important influence on their vibration characteristics. Different boundary conditions (such as fixed support, simply supported, free, etc.) will cause the thin plate to have different natural frequencies and vibration modes, thus affecting its deflection distribution.

[0082] The deflection of a metal sheet during vibration can be obtained by solving the vibration differential equation. Generally speaking, it is necessary to establish the vibration equation of the thin plate, consider its boundary conditions, initial conditions and other factors, and solve the equation by numerical or analytical methods to obtain the deflection distribution of the thin plate during vibration.

[0083] It should also be noted that the bending stiffness of a metal sheet is an important physical quantity that measures its ability to resist deformation when subjected to a bending load. It is usually closely related to the elastic modulus of the metal sheet and the geometric characteristics of the structure. The thickness of the sheet directly affects its bending stiffness. Generally speaking, the greater the thickness, the greater the bending stiffness. The bending stiffness D of a metal sheet is calculated by the following formula:

[0084]

[0085] Where: E is the elastic modulus of the metal sheet, μ is the Poisson's ratio, and h is the thickness of the metal sheet.

[0086] It should be noted here that Poisson's ratio refers to the absolute value of the ratio of the transverse normal strain (strain perpendicular to the load direction) to the axial normal strain (strain parallel to the load direction) when the material is subjected to uniaxial tension or compression. This ratio reflects the degree of lateral deformation of the material when it is subjected to uniaxial stress.

[0087] In block 105 , a general solution of a differential equation for free vibration of a unidirectional tension metal sheet is characterized based on the case where two pairs of edges of the unidirectional tension metal sheet are simply supported and in tension and the other two pairs of edges are arbitrarily supported.

[0088] The boundary conditions of metal sheets have an important influence on their vibration characteristics. The boundary conditions of metal sheets refer to the restrictions or constraints on the boundaries of metal sheets in mechanical analysis or engineering applications. These conditions are crucial for understanding the mechanical behavior of metal sheets, structural analysis and design. Generally speaking, the boundary conditions of metal sheets can be mainly divided into: fixed boundary, simply supported boundary, free boundary and sliding boundary.

[0089] In this embodiment, two opposite sides of the metal sheet are simply supported and in tension, and the other two sides of the metal sheet are arbitrarily supported. The simply supported boundary condition means that the thin plate can only move freely in one direction on the boundary, usually perpendicular to the boundary, and is restricted in other directions. On the simply supported boundary, the thin plate cannot rotate about any axis, but can deflect in the direction perpendicular to the boundary.

[0090] Based on the above situation, the general solution of the differential equation characterizing the free vibration of the unidirectional tension metal plate is:

[0091]

[0092] Where: W j (x, y) is the vibration mode function of the metal plate, T j (t) is the time-dependent amplitude function, Y j (y) represents the jth mode shape function along the y direction, and a is the length of the plate.

[0093] It should be noted that for simply supported boundary conditions, the vibration mode function of the metal plate adopts the sine function The sine function satisfies the boundary conditions of simple support, and the displacement is zero when x=0 and x=a (these two positions are hinged).

[0094] In block 107 , a frequency equation of the unidirectional tension metal sheet is established based on the free vibration differential equation of the unidirectional tension metal sheet and the general solution of the equation.

[0095] Substituting the above formula (2) into formula (1) and separating the variables, the frequency equation of the unidirectional tension metal sheet is obtained, as shown in formula (3):

[0096]

[0097] Where: Y″(y) is the second-order derivative of Y.

[0098] In block 109 , based on the obtained vibration frequency of the unidirectional tension metal sheet, the uniform tension acting on the edge of the unidirectional tension metal sheet is obtained, thereby realizing stress identification of the tension acting on both ends of the unidirectional tension metal sheet.

[0099] Formula (3) is transformed into the following formula (4). Formula (4) and related parameters can be used to calculate the uniform tension N acting on the edge of a unidirectional tensioned metal sheet: x :

[0100]

[0101] Where: j is the j-th vibration frequency of the unidirectional tension metal plate.

[0102] Based on the derivation of formula (3), formula (4) is obtained, and the uniform tensile force N acting on the edge of the unidirectional tension metal sheet is obtained: x , by solving N x The value of can be used to realize the stress identification of the tensile force at both ends of the unidirectional tension metal plate.

[0103] In summary, the stress identification method provided by the present invention combines mechanical analysis with numerical analysis, collects data through sensors, processes and analyzes them, and overcomes the problem that traditional methods are difficult to accurately solve for complex structures or complex load conditions by establishing partial differential equations and using computers to solve them. It can handle complex structural problems and provide high-precision non-destructive stress identification. The present invention has broad application prospects in multiple fields such as architecture, decoration, and engineering structures.

[0104] Figure 3 FIG. 2 shows a schematic block diagram of an in-plane stress identification device 200 for a unidirectional tension metal sheet according to some embodiments of the present invention. Figure 3 As shown, the identification device 200 includes a vibration frequency monitoring module 201 , a free vibration differential equation establishing module 203 , a free vibration differential equation general solution characterization module 205 , a frequency equation establishing module 207 , and a calculation module 209 .

[0105] The vibration frequency monitoring module 201 is configured to monitor the mode of the unidirectional tension metal sheet in real time to obtain the vibration frequency of the unidirectional tension metal sheet, wherein two pairs of sides of the unidirectional tension metal sheet are simply supported and tensioned, and the other two pairs of sides are arbitrarily supported;

[0106] The free vibration differential equation establishing module 203 is configured to establish the free vibration differential equation of the unidirectional tension metal sheet based on the Keuchhof plate and shell theory;

[0107] The free vibration differential equation general solution characterization module 205 is configured to characterize the general solution of the free vibration differential equation of the unidirectional tension metal sheet based on the situation that two pairs of edges of the unidirectional tension metal sheet are simply supported and tensioned and the other two pairs of edges are arbitrarily supported;

[0108] The frequency equation establishing module 207 is configured to establish a frequency equation of the unidirectional tension metal sheet based on the free vibration differential equation of the unidirectional tension metal sheet and the general solution of the equation;

[0109] The calculation module 209 is configured to calculate the uniform tension acting on the edge of the unidirectional tension metal sheet based on the vibration frequency of the unidirectional tension metal sheet by the frequency equation, so as to realize the stress identification of the tension at both ends of the unidirectional tension metal sheet.

[0110] Figure 4 The schematic block diagram of an example electronic device 300 that can be used to implement an embodiment of the present invention is shown. The electronic device 300 includes: one or more processors 301; and a storage device 303 for storing one or more programs. When the one or more programs are executed by the one or more processors, the one or more processors implement Figure 1The identification method 100 shown. The electronic device 300 is intended to represent various forms of digital computers, such as laptop computers, desktop computers, workstations, personal digital assistants, servers, blade servers, mainframe computers, and other suitable computers. The electronic device can also represent various forms of mobile devices, such as personal digital processing, cellular phones, smart phones, wearable devices, and other similar computing devices. The components shown in the present invention, their connections and relationships, and their functions are only examples and are not intended to limit the implementation of the present invention described and / or required herein.

[0111] like Figure 5 As shown, an application scenario of a computer-readable storage medium, or a computing device 400, is shown, including a CPU 401 (computing unit), which can perform various appropriate actions and processes according to a computer program stored in a ROM 402 (read-only memory) or a computer program loaded from a storage unit 408 into a random access RAM 403 (memory). In the RAM 403, various programs and data required for the operation of the computing device 400 can also be stored. The CPU 401, the ROM 402, and the RAM 403 are connected to each other via a bus 404. An I / O interface 405 (input / output interface) is also connected to the bus 404.

[0112] A number of components in the computing device 400 are connected to the I / O interface 405, including: an input unit 406, such as a keyboard, a mouse, etc.; an output unit 407, such as various types of displays, speakers, etc.; a storage unit 408, such as a disk, an optical disk, etc.; and a communication unit 409, such as a network card, a modem, a wireless communication transceiver, etc. The communication unit 409 allows the computing device 400 to exchange information / data with other devices through a computer network such as the Internet and / or various telecommunication networks.

[0113] CPU 401 can be various general and / or special processing components with processing and computing capabilities. Some examples of CPU 401 include, but are not limited to, central processing units (CPUs), graphics processing units (GPUs), various special artificial intelligence (AI) computing chips, various computing units running machine learning model algorithms, digital signal processors (DSPs), and any appropriate processors, controllers, microcontrollers, etc. CPU 401 performs the various methods and processes described above, such as recognition method 100. For example, in some embodiments, recognition method 100 can be implemented as a computer software program, which is tangibly contained in a computer-readable storage medium, such as storage unit 408. In some embodiments, part or all of the computer program can be loaded and / or installed on computing device 400 via ROM 402 and / or communication unit 409. When the computer program is loaded into RAM 403 and executed by CPU 401, one or more steps of recognition method 100 described above can be performed. Alternatively, in other embodiments, CPU 401 can be configured to perform recognition method 100 in any other appropriate manner (e.g., by means of firmware).

[0114] Various embodiments of the systems and techniques described above in the present invention can be implemented in digital electronic circuit systems, integrated circuit systems, field programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), application specific standard products (ASSPs), systems on chips (SOCs), load programmable logic devices (CPLDs), computer hardware, firmware, software, and / or combinations thereof. These various embodiments may include: being implemented in one or more computer programs that can be executed and / or interpreted on a programmable system including at least one programmable processor, which can be a special purpose or general purpose programmable processor that can receive data and instructions from a storage system, at least one input device, and at least one output device, and transmit data and instructions to the storage system, the at least one input device, and the at least one output device.

[0115] The program code for implementing the method of the present invention can be written in any combination of one or more programming languages. These program codes can be provided to a processor or controller of a general-purpose computer, a special-purpose computer or other programmable data processing device, so that the program code, when executed by the processor or controller, enables the functions / operations specified in the flow chart and / or block diagram to be implemented. The program code can be executed entirely on the machine, partially on the machine, partially on the machine as a stand-alone software package and partially on a remote machine, or entirely on a remote machine or server.

[0116] In the context of the present invention, a computer-readable storage medium may be a tangible medium that may contain or store a program for use by or in conjunction with an instruction execution system, device, or equipment. A computer-readable storage medium may be a machine-readable signal medium or a machine-readable storage medium. A computer-readable storage medium may include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, devices, or equipment, or any suitable combination of the foregoing. A more specific example of a computer-readable storage medium may include an electrical connection based on one or more lines, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

[0117] The embodiments of the present invention have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A method for identifying in-plane stress of a unidirectionally tensioned metal sheet, characterized in that: include: Real-time monitoring of the mode of a unidirectional tensioned metal sheet to obtain the vibration frequency of the unidirectional tensioned metal sheet, wherein two pairs of edges of the unidirectional tensioned metal sheet are simply supported and tensioned, and the other two pairs of edges are arbitrarily supported; Based on Keurgehof plate and shell theory, the free vibration differential equation of unidirectional tension metal plate is established; The general solution of the differential equation for free vibration of a unidirectional tension metal plate is presented based on the case where two pairs of edges of the unidirectional tension metal plate are simply supported and tensioned and the other two pairs of edges are arbitrarily supported. Based on the free vibration differential equation of the unidirectional tension metal sheet and the general solution of the equation, the frequency equation of the unidirectional tension metal sheet is established; Based on the vibration frequency of the unidirectional tension metal sheet, the uniform tension acting on the edge of the unidirectional tension metal sheet is calculated by the frequency equation, so as to realize the stress identification of the tension at both ends of the unidirectional tension metal sheet.

2. The stress identification method according to claim 1, characterized in that: The real-time monitoring of the mode of the unidirectional tension metal sheet and the acquisition of the vibration frequency of the unidirectional tension metal sheet are specifically: Sensors are arranged on the unidirectional tension metal sheet to monitor the mode of the unidirectional tension metal sheet in real time to obtain the vibration frequency of the unidirectional tension metal sheet.

3. The stress identification method according to claim 1, characterized in that: The free vibration differential equation of the unidirectional tension metal sheet is established as formula (1): Where: is the mass per unit area of ​​the metal sheet, D is the bending stiffness of the metal sheet, N x is the uniform tension acting on the edge of the metal plate, w(x,y,t) is the deflection of the metal plate when it vibrates, x is the lateral displacement, y is the longitudinal displacement, and t is the time.

4. The stress identification method according to claim 3, characterized in that: The bending stiffness D of the metal sheet is calculated by the following formula: Where: E is the elastic modulus of the metal sheet, μ is the Poisson's ratio, and h is the thickness of the metal sheet.

5. The stress identification method according to claim 3, characterized in that: The general solution of the differential equation characterizing the free vibration of the unidirectional tension metal sheet is as follows: Where: W j (x, y) is the vibration mode function of the metal plate, T j (t) is the time-dependent amplitude function, Y j (y) represents the jth mode shape function along the y direction, and a is the length of the plate.

6. The stress identification method according to claim 5, characterized in that: The frequency equation of the unidirectional tension metal sheet is established based on the free vibration differential equation of the unidirectional tension metal sheet and the general solution of the equation as follows: Substituting formula (2) into formula (1) and separating the variables, we can obtain the frequency equation of the unidirectional tension metal sheet, as shown in formula (3): Where: Y″(y) is the second-order derivative of Y.

7. The stress identification method according to claim 6, characterized in that: Based on the obtained vibration frequency of the unidirectional tension metal sheet, the uniform tension N acting on the edge of the unidirectional tension metal sheet is calculated using the following formula (4): x : Where: j is the jth vibration frequency of the metal plate under unidirectional tension.

8. A device for identifying in-plane stress of a unidirectionally tensioned metal sheet, characterized in that: include: A vibration frequency monitoring module is configured to monitor the mode of a unidirectional tension metal sheet in real time to obtain the vibration frequency of the unidirectional tension metal sheet, wherein two pairs of edges of the unidirectional tension metal sheet are simply supported and tensioned, and the other two pairs of edges are arbitrarily supported; A free vibration differential equation building module is configured to build a free vibration differential equation of a unidirectional tension metal sheet based on Keuchhof plate and shell theory; A free vibration differential equation general solution characterization module is configured to characterize a general solution of a free vibration differential equation of a unidirectional tension metal plate based on a case where two pairs of edges of the unidirectional tension metal plate are simply supported and tensioned and the other two pairs of edges are arbitrarily supported; A frequency equation establishing module is configured to establish a frequency equation of the unidirectional tension metal sheet based on a free vibration differential equation of the unidirectional tension metal sheet and a general solution of the equation; The calculation module is configured to calculate the uniform tension acting on the edge of the unidirectional tension metal plate based on the vibration frequency of the unidirectional tension metal plate by the frequency equation, so as to realize the stress identification of the tension at both ends of the unidirectional tension metal plate.

9. An electronic device, comprising: one or more processors; as well as A storage device for storing one or more programs, when the one or more programs are executed by the one or more processors, the one or more processors implement the method described in any one of claims 1 to 7.

10. A computer-readable storage medium having a computer program stored thereon, wherein when the program is executed by a processor, the method according to any one of claims 1 to 7 is implemented.

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