Composite material plate opening strength analysis method, device, equipment and medium

Abstract

The invention discloses a method, a device and equipment for analyzing the opening strength of a composite material plate and a medium. Comprising the steps that the safety margin of an unopened composite material plate is calculated, and when the safety margin is smaller than or equal to 0, the reinforcing offset amount is determined according to the safety margin; the reinforcing strain of the unopened composite material plate is calculated in combination with the reinforcing offset; calculating the unreinforced hole edge strain of the opened composite material plate according to the preset opening size, and analyzing the opening strength of the composite material plate according to the reinforced strain and the unreinforced hole edge strain. By means of the safety margin, whether the initial strength of the composite material plate meets the requirement or not can be judged, the strengthening offset amount is quantitatively determined based on the safety margin, and design blindness is avoided. By acquiring the strain state of the unopened plate after reinforcement, deviation of subsequent strength analysis caused by lack of strain data after reinforcement is avoided. By analyzing the reinforced strain and the unreinforced hole edge strain, the actual strength of the opening reinforced structure can be evaluated, the workload is reduced, and the analysis efficiency is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of material analysis, in particular to a composite plate opening strength analysis method, device, equipment and medium. BACKGROUND

[0002] In the field of composite structure design, composite flat plates are widely used in aerospace and other fields due to their lightweight and high strength characteristics. However, in practical applications, openings are often made in composite flat plates to meet the needs of installation and weight reduction. However, the openings can cause significant stress concentration in the local area of the flat plate, directly leading to a decrease in structural strength. Therefore, local unilateral strengthening design must be performed on the opening area to ensure the safety of the structure.

[0003] In the prior art, finite element analysis method is used to evaluate the hole edge strength, i.e., a finite element model of the opening structure is first established, and then strength calculation is performed in combination with specific working conditions. In some scenarios, the hole edge strain in the un-strengthened state is also calculated preliminarily based on the pre-set opening size, providing a reference for subsequent strengthening design.

[0004] Although the finite element analysis method of the prior art can calculate the hole edge strength, the workload is extremely large, especially in complex scenarios such as aircraft design, where the model and parameters need to be repeatedly adjusted, seriously affecting the size design efficiency. It is difficult to quickly and accurately evaluate the actual strength of the opening strengthening structure, and it is difficult to meet the dual needs of efficient design and safety verification. SUMMARY

[0005] The present application provides a composite plate opening strength analysis method, device, equipment and medium, which solves the technical problem of insufficient strength or even damage at the opening of the composite plate due to stress concentration by using unilateral strengthening structure at the opening of the composite plate and combining strain analysis, stress concentration coefficient calculation and safety margin evaluation.

[0006] According to an aspect of the present application, a composite plate opening strength analysis method is provided, which comprises:

[0007] Calculating the safety margin of the un-opened composite plate, and when the safety margin is less than or equal to 0, determining the strengthening offset based on the safety margin;

[0008] Calculating the strengthening strain of the un-opened composite plate in combination with the strengthening offset;

[0009] Calculating the un-strengthened hole edge strain of the opened composite plate based on the pre-set opening size, and performing composite plate opening strength analysis based on the strengthening strain and the un-strengthened hole edge strain.

[0010] Optionally, the safety margin of the unopened composite material plate is calculated, including: obtaining basic mechanical parameters of the unopened composite material plate, calculating the mid-plane force flow and the bending moment flow according to the basic mechanical parameters, and calculating the surface strain of the unopened composite material plate according to the mid-plane force flow and the bending moment flow, wherein the basic mechanical parameters include the line force, the bending moment, the shell element offset and the thickness of the laminated plate; the strength of the composite material plate is checked by using a strain checking method based on the surface strain, and the safety margin is calculated.

[0011] Optionally, the reinforcing offset is determined according to the safety margin, including: performing single-side reinforcement on the hole edge according to the safety margin, and taking the negative value of the safety margin and the original thickness as the single-side reinforcement thickness; and taking half of the single-side reinforcement thickness as the reinforcing offset.

[0012] Optionally, the reinforcing strain of the unopened composite material plate is calculated in combination with the reinforcing offset, including: replacing the shell element offset in the basic mechanical parameters with the reinforcing offset to calculate the reinforced mid-plane force flow and the bending moment flow; and calculating the reinforcing strain of the unopened composite material plate according to the reinforced mid-plane force flow and the bending moment flow.

[0013] Optionally, the un-reinforced hole edge strain of the opened composite material plate is calculated according to the preset opening size, including: obtaining the far-field stress of the hole edge according to the preset opening size, and calculating the disturbance stress of the hole edge by using the Lekhniski method; and determining the un-reinforced hole edge strain of the opened composite material plate according to the far-field stress and the disturbance stress.

[0014] Optionally, the composite material plate opening strength is analyzed according to the reinforcing strain and the un-reinforced hole edge strain, including: calculating the hole edge stress concentration coefficient according to the reinforcing strain and the un-reinforced hole edge strain; calculating the reinforced hole edge strain of the opened composite material plate according to the hole edge stress concentration coefficient in combination with the surface strain; calculating the principal strain according to the reinforced hole edge strain, and calculating the reinforcing safety margin based on the principal strain, and analyzing the composite material plate opening strength according to the reinforcing safety margin.

[0015] Optionally, the composite material plate opening strength is analyzed according to the reinforcing safety margin, including: judging whether the reinforcing safety margin meets a preset range, if yes, generating a final opening reinforcing structure; otherwise, adjusting the single-side reinforcement thickness based on the reinforcing safety margin until the preset range is met, and generating the final opening reinforcing structure.

[0016] According to another aspect of the present application, a composite material plate opening strength analysis device is provided, which comprises:

[0017] The reinforcing offset calculation module is configured to calculate the safety margin of the unopened composite material plate, and when the safety margin is less than or equal to 0, determine the reinforcing offset according to the safety margin.

[0018] The reinforced strain calculation module is configured to calculate the reinforced strain of the unopened composite material plate in combination with the reinforced bias amount.

[0019] The opening strength analysis module is configured to calculate the un-reinforced hole edge strain of the opened composite material plate according to the preset opening size, and perform opening strength analysis of the composite material plate according to the reinforced strain and the un-reinforced hole edge strain.

[0020] According to another aspect of the present application, an electronic device is provided, the electronic device comprising:

[0021] at least one processor;

[0022] and a memory connected in communication with the at least one processor;

[0023] wherein the memory stores a computer program capable of being executed by the at least one processor, and the computer program is executed by the at least one processor to enable the at least one processor to perform the opening strength analysis method of the composite material plate according to any one of the embodiments of the present application.

[0024] According to another aspect of the present application, a computer readable storage medium is provided, the computer readable storage medium stores computer instructions for enabling a processor to perform the opening strength analysis method of the composite material plate according to any one of the embodiments of the present application when executed by the processor.

[0025] The technical solution of the embodiments of the present application can determine whether the initial strength of the unopened composite material plate meets the requirements through the safety margin, and quantitatively determine the reinforced bias amount based on the safety margin, thereby avoiding the blindness of the reinforced bias amount design and providing accurate parameter basis for subsequent reinforced structure design. By calculating the reinforced strain, the strain state of the unopened plate after reinforcement can be accurately obtained, thereby avoiding the deviation of subsequent strength analysis due to the lack of reinforced strain data. By combining the reinforced strain and the un-reinforced hole edge strain for analysis, the actual strength of the opening reinforced structure can be accurately evaluated, thereby reducing the workload and improving the analysis efficiency.

[0026] It should be understood that the content described in this part is not intended to identify key or important features of the embodiments of the present application, nor is it used to limit the scope of the present application. Other features of the present application will become apparent from the following description. BRIEF DESCRIPTION OF DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0028] Figure 1 is a flow chart of a composite material plate opening strength analysis method according to an embodiment of the present application;

[0029] Figure 2 is a flow chart of another composite material plate opening strength analysis method according to another embodiment of the present application;

[0030] Figure 3 is a structural schematic diagram of a composite material plate opening strength analysis device according to an embodiment of the present application;

[0031] Figure 4 is a structural schematic diagram of an electronic device for implementing a composite material plate opening strength analysis method according to an embodiment of the present application. DETAILED DESCRIPTION

[0032] In order to make the personnel in the technical field better understand the present application, the technical solutions in the embodiments of the present application will be described clearly and completely below in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor should belong to the scope of protection of the present application.

[0033] It should be noted that the terms "first", "second", and the like in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and do not necessarily have to describe a specific order or sequence. It should be understood that the data thus used can be interchanged under appropriate circumstances, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device including a series of steps or units does not have to be limited to those steps or units clearly listed, but can include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0034] Embodiment one

[0035] Figure 1 A flow chart of a composite material plate opening strength analysis method is provided for the first embodiment of the present application. The present embodiment can be applicable to the composite material strength analysis scene. The method can be executed by a composite material plate opening strength analysis device. The composite material plate opening strength analysis device can be realized in the form of hardware and / or software. The composite material plate opening strength analysis device can be configured in a computer controller. As shown in the figure, the method comprises: Figure 1 ​

[0036] S110, calculate the safety margin of the unopened composite material plate, and determine the reinforcement bias amount according to the safety margin when the safety margin is less than or equal to 0.

[0037] The safety margin is an index for measuring whether the structural strength of the composite material plate meets the design requirements, and is used to judge whether the structure has sufficient strength reserve under a specific working condition. The reinforcement bias amount is the thickness offset after single-sided reinforcement of the unopened composite material plate hole edge, and is used to correct the structural geometric parameters to ensure the accuracy of subsequent strain calculation. When the safety margin is less than or equal to 0, it indicates that the strength of the unopened composite material plate does not meet the standard, and single-sided reinforcement is required for the hole edge.

[0038] Optionally, the safety margin of the unopened composite material plate is calculated, including: obtaining the basic mechanical parameters of the unopened composite material plate, calculating the mid-surface force flow and the bending moment flow according to the basic mechanical parameters, and calculating the surface strain of the unopened composite material plate according to the mid-surface force flow and the bending moment flow, wherein the basic mechanical parameters include linear force, bending moment, shell element offset amount and laminate thickness; based on the surface strain, the strain checking method is used to check the strength of the composite material plate, and the safety margin is calculated.

[0039] The linear force refers to the normal force flow along the x and y directions and the shear force flow in the xy plane at the position of the shell element reference plane, with the unit of N / mm. The bending moment refers to the normal bending moment flow around the x and y axes and the torque flow around the normal of the xy plane at the position of the shell element reference plane, with the unit of N・mm / mm. The shell element offset amount refers to the offset distance of the reference plane relative to the mid-plane of the laminate set in the shell element attribute, with the unit of mm. The laminate thickness is the overall thickness of the unopened composite material plate, with the unit of mm. The mid-surface force flow and the bending moment flow are calculated using the following formula (1):

[0040] ; (1)

[0041] wherein, , , represents the force flow at the position of the shell element reference plane, , , represents the bending moment flow at the position of the shell element reference plane, represents the force flow at the position of the shell element mid-plane, represents the bending moment flow at the position of the shell element mid-plane, Z0 represents the offset amount set in the shell element attribute, and t represents the laminate thickness. Then, the controller can calculate the surface strain of the unopened composite material plate according to the mid-surface force flow and the bending moment flow. The surface strain is calculated using the following formulas (2) and (3):

[0042] ; (2)

[0043] (3)

[0044] wherein, denotes the strain considering the bias; denotes the strain at the surface position in the shell element; denotes the curvature at the surface position in the shell element; z denotes the distance from the point to the surface where the strain is calculated, and z = t / 2, -t / 2 are taken respectively to calculate the strain of the upper and lower surfaces, and z = 0 is taken to calculate the strain of the middle surface. Finally, the controller can check the strength of the composite plate based on the surface strain by using a strain checking method and calculate the safety margin. The strain checking method is to compare the actual surface strain of the unopened composite plate with the allowable strain of the material itself. If the actual strain is less than the allowable strain, it means that the structural strength meets the design requirements, and the safety margin is positive, and the larger the value is, the more sufficient the safety reserve is. If the actual strain is equal to the allowable strain, the safety margin is 0, and if the actual strain is greater than the allowable strain, the safety margin is negative, indicating that the structural strength is insufficient.

[0045] Optionally, the reinforcing bias amount is determined according to the safety margin, comprising: performing single-sided reinforcement on the hole edge according to the safety margin, and taking the negative value of the safety margin and the original thickness as the single-sided reinforcement thickness; and taking half of the single-sided reinforcement thickness as the reinforcing bias amount.

[0046] Specifically, when the safety margin is less than or equal to 0, it means that the strength of the unopened composite plate has failed to meet the design requirements, and the strength gap needs to be made up by single-sided reinforcement, and the negative value of the safety margin can directly be used as the basis for calculating the single-sided reinforcement thickness, because it quantifies the degree of insufficient strength. That is, if the original composite plate thickness is t, the single-sided reinforcement thickness is the product of the original thickness and the negative value of the safety margin.

[0047] wherein, the single-sided reinforcement refers to increasing the thickness on one side of the laminate, rather than symmetrically thickening. Therefore, in order to ensure that the subsequent calculation of the reinforcing strain can accurately reflect the influence of the geometric offset of the reinforced structure on the stress state, the offset amount needs to be determined with the middle surface of the laminate as the center, and half of the single-sided reinforcement thickness, i.e. the offset distance of the reinforced part relative to the middle surface, is taken as the reinforcing bias amount.

[0048] S120, calculating the reinforcing strain of the unopened composite plate in combination with the reinforcing bias amount.

[0049] wherein, the reinforcing strain is the strain of the upper and lower surfaces of the unopened composite plate after single-sided reinforcement on the hole edge, which can reflect the improvement of the single-sided reinforcement on the stress state of the structure, and is the basis for subsequent analysis of the strength of the opening structure.

[0050] Optionally, the reinforcing strain of the unopened composite material plate is calculated in combination with the reinforcing bias, including: the reinforcing bias is used to replace the shell element bias in the basic mechanical parameters to calculate the reinforced mid-plane force flow and the bending moment flow; and the reinforcing strain of the unopened composite material plate is calculated according to the reinforced mid-plane force flow and the bending moment flow.

[0051] It can be known that the unilateral reinforcement changes the geometric reference of the original structure, and the shell element bias in the original basic mechanical parameters needs to be replaced by the reinforcing bias to ensure that the calculation reference is consistent with the actual geometric state of the reinforced structure. Subsequently, the calculation logic of the above formula (1) is used to calculate the mid-plane force flow and the bending moment flow of the reinforced laminate plate by using the replaced reinforcing bias as the core parameter in combination with the original linear force, the bending moment and the thickness of the laminate plate. The result reflects the correction of the unilateral reinforcement on the internal force distribution of the structure. Then, according to the strain calculation principle of the above formula (2) and (3), the reinforced mid-plane force flow will correspondingly generate the reinforced mid-plane strain, and the reinforced mid-plane bending moment flow will correspondingly generate the reinforced mid-plane curvature. That is, the distance from the point to the mid-plane, the reinforced mid-plane strain, the mid-plane curvature and the z value are substituted into formula (2) and (3), and finally the upper and lower surface strains of the unopened composite material plate are obtained, which are the reinforcing strains.

[0052] S130, calculating the un-reinforced hole edge strain of the opened composite material plate according to the preset opening size, and performing opening strength analysis of the composite material plate according to the reinforcing strain and the un-reinforced hole edge strain.

[0053] The preset opening size refers to the opening related geometric parameters preset on the composite material plate. The un-reinforced hole edge strain is the strain generated in the hole edge region of the composite material plate containing the preset opening size when the hole edge is not subjected to unilateral reinforcement. The stress concentration effect caused by the opening needs to be considered, and the Lehknitskii method is used for calculation.

[0054] Optionally, the un-reinforced hole edge strain of the opened composite material plate is calculated according to the preset opening size, including: the far field stress of the hole edge is obtained according to the preset opening size, and the Lehknitskii method is used to calculate the disturbance stress of the hole edge; and the un-reinforced hole edge strain of the opened composite material plate is determined according to the far field stress and the disturbance stress.

[0055] In one specific embodiment, taking an elliptical hole as an example, the preset opening size includes an elliptical semi-major axis and an elliptical semi-minor axis, the preset opening size directly determines the distribution characteristics of the stress concentration at the hole edge, and is a basic geometric parameter for subsequent stress calculation. The far-field stress refers to the stress of the opening composite plate in a region far away from the hole edge. The far-field stress is obtained based on the stress state of the unopened composite plate, that is, the linear force, the bending moment and the thickness of the laminated plate when the unopened plate is calculated, and the basic stress level of the structure without opening interference is derived by combining the correlation between stress and force flow and bending moment flow. The hole edge disturbance stress is the additional stress generated in the hole edge region due to the existence of the opening, which needs to be calculated by using the Lekhnitski method. The complex stress function is calculated by using the following formula (4):

[0056] ; (4)

[0057] wherein, represents the complex stress function, , is an imaginary unit, represents the elliptical semi-major axis, represents the elliptical semi-minor axis, represents a complex variable, represents a complex root, represents a coefficient in the expansion of the complex stress function. The complex stress function can describe the distribution law of the stress at the hole edge, and then the complex roots of the characteristic equation are solved by using the flexibility matrix coefficients of the plane problem, which are calculated by using the following formula (5):

[0058] ; (5)

[0059] wherein, represents the normal strain in the x direction, represents the normal strain in the y direction, represents the shear strain in the xy plane, represents the normal stress in the x direction, represents the normal stress in the y direction, represents the shear stress in the xy plane, represents the flexibility matrix element of the plane problem, and the complex roots reflect the influence of the anisotropy characteristics of the composite material on the stress transmission. Finally, the disturbance stress is calculated by combining the real part of the complex variable, which is calculated by using the following formula (6):

[0060] ; (6)

[0061] wherein, represents the disturbance normal stress in the x direction, represents the disturbance normal stress in the y direction, represents the disturbance shear stress, represents the complex stress function, Represents the real part of a complex number. To represent a complex variable, , Characteristic equation The complex roots, and , The stress reflects the interference effect of the opening on the local stress field at the edge of the hole.

[0062] It should be noted that the strain and stress of the composite material satisfy the constitutive relation, and the total stress at the hole edge is formed by the superposition of the far-field stress and the disturbance stress, and is calculated using the following formula (7):

[0063] (7)

[0064] in, This represents the total normal stress in the x-direction at the edge of the hole. This represents the total normal stress in the y-direction at the edge of the hole. This represents the total shear stress at the edge of the hole. This represents the normal stress in the far-field x-direction. This represents the normal stress in the y-direction of the far field. Represents the shear stress in the far field. This represents the perturbation normal stress in the x-direction. This represents the perturbation normal stress in the y-direction. This represents the perturbation shear stress. First, the calculated far-field stress is added to the perturbation stress to obtain the total stress at the hole edge in the unreinforced state. Then, using the compliance matrix of the composite material, the total stress is converted into the corresponding strain. The strain components in each direction are calculated by multiplying the stress by the compliance coefficient. The final hole edge strain is the unreinforced hole edge strain.

[0065] The technical solution of this invention, through a safety margin, can determine whether the initial strength of the unopened composite material plate meets the requirements, and quantitatively determine the reinforcement offset based on the safety margin, avoiding the blind design of the reinforcement offset and providing accurate parameter basis for subsequent reinforcement structure design. By calculating the reinforcement strain, the strain state of the unopened plate after reinforcement can be accurately obtained, avoiding deviations in subsequent strength analysis due to the lack of strain data after reinforcement. By combining the reinforcement strain with the strain at the edge of the unreinforced hole for analysis, the actual strength of the open reinforcement structure can be accurately evaluated, reducing workload and improving analysis efficiency.

[0066] Example 2

[0067] Figure 2A flow chart of a composite material plate opening strength analysis method provided for the second embodiment of the present application, the embodiment adds a specific process of composite material plate opening strength analysis according to the strengthened strain and the unstrengthened hole edge strain on the basis of the first embodiment. The specific content of steps S210-S220 is substantially the same as steps S110-S120 in the first embodiment, and therefore will not be described again in the present embodiment. As shown in the first embodiment, the method comprises: Figure 2

[0068] S210, calculate the safety margin of the unopened composite material plate, and when the safety margin is less than or equal to 0, determine the strengthening bias according to the safety margin.

[0069] Optionally, the safety margin of the unopened composite material plate is calculated, including: obtaining the basic mechanical parameters of the unopened composite material plate, calculating the mid-surface force flow and the bending moment flow according to the basic mechanical parameters, and calculating the surface strain of the unopened composite material plate according to the mid-surface force flow and the bending moment flow, wherein the basic mechanical parameters include linear force, bending moment, shell element bias and laminate thickness; based on the surface strain, the strength of the composite material plate is checked by using the strain checking method, and the safety margin is calculated.

[0070] Optionally, the strengthening bias is determined according to the safety margin, including: unilaterally strengthening the hole edge according to the safety margin, and taking the negative value of the safety margin and the original thickness as the unilateral strengthening thickness; taking half of the unilateral strengthening thickness as the strengthening bias.

[0071] S220, calculate the strengthening strain of the unopened composite material plate in combination with the strengthening bias.

[0072] Optionally, the strengthening strain of the unopened composite material plate is calculated in combination with the strengthening bias, including: replacing the shell element bias in the basic mechanical parameters with the strengthening bias to calculate the strengthened mid-surface force flow and the bending moment flow; and calculating the strengthening strain of the unopened composite material plate according to the strengthened mid-surface force flow and the bending moment flow.

[0073] S230, calculate the unstrengthened hole edge strain of the opened composite material plate according to the preset opening size.

[0074] Optionally, the unstrengthened hole edge strain of the opened composite material plate is calculated according to the preset opening size, including: obtaining the far-field stress of the hole edge according to the preset opening size, and calculating the disturbance stress of the hole edge by using the Lekhnitskii method; and determining the unstrengthened hole edge strain of the opened composite material plate according to the far-field stress and the disturbance stress.

[0075] S240, calculate the hole edge stress concentration coefficient according to the strengthened strain and the unstrengthened hole edge strain.

[0076] ​It can be known that the un-reinforced hole edge strain caused by the stress concentration effect of the opening is greater than the strain of the un-opened plate, and the reinforced strain is the strain of the un-opened plate after single-side reinforcement, which can be used as a benchmark for evaluating the influence of the opening. The hole edge stress concentration coefficient is calculated by the following formula (8):

[0077] ; (8)

[0078] wherein, represents the stress concentration coefficient in the x direction, represents the stress concentration coefficient in the y direction, represents the shear stress concentration coefficient in the xy plane, represents the hole edge strain of the x direction opening plate, represents the strain of the x direction intact plate, represents the hole edge strain of the y direction opening plate, represents the strain of the y direction intact plate, represents the hole edge strain of the xy plane opening plate, represents the strain of the xy plane intact plate. By taking the reinforced strain as a benchmark, the strain concentration coefficient is calculated by comparing with the un-reinforced hole edge strain, and the coefficient reflects the amplification multiple of the hole edge strain caused by the opening relative to the un-opened reinforced state.

[0079] S250, according to the hole edge stress concentration coefficient, the reinforced hole edge strain of the opening composite plate is calculated in combination with the surface strain.

[0080] Specifically, when the hole edge is single-side reinforced, the hole edge strain of the opening structure needs to consider the strain improvement caused by the reinforcement and the strain concentration effect of the opening. The calculated hole edge stress concentration coefficient is multiplied by the surface strain of the un-opened composite plate, and the upper and lower surface strains of the hole edge of the opening structure after single-side reinforcement of the hole edge are derived, which is the reinforced hole edge strain, and fully reflects the actual strain state of the hole edge under the combined action of single-side reinforcement and opening strain concentration. The reinforced hole edge strain is calculated by the following formula (9):

[0081] ; (9)

[0082] wherein, represents the stress concentration coefficient in the x direction, represents the hole edge strain of the x direction opening plate on the Z1 surface, represents the hole edge strain of the x direction opening plate on the Z2 surface, represents the strain of the intact plate in the x direction on the Z1 surface, represents the hole edge strain of the y direction opening plate on the Z1 surface, represents the hole edge strain of the xy plane opening plate on the Z1 surface, a strain of a perfect plate in the x direction of the Z2 surface, a hole edge strain of the open plate in the y direction of the Z2 surface, a strain of a perfect plate in the x direction of the Z1 surface, a hole edge strain of the open plate in the xy plane of the Z2 surface.

[0083] S260, calculate the principal strain according to the reinforced hole edge strain, and calculate the reinforced safety margin based on the principal strain, and perform composite plate opening strength analysis according to the reinforced safety margin.

[0084] Specifically, the principal strain is calculated by using the following formula (10):

[0085] ; (10)

[0086] wherein, a normal strain in the x direction, a normal strain in the y direction, a shear strain in the xy plane, a maximum principal strain, a minimum principal strain.

[0087] Optionally, the composite plate opening strength analysis according to the reinforced safety margin comprises: judging whether the reinforced safety margin meets a preset range, if yes, generating a final opening reinforcing structure; otherwise, adjusting the single-side reinforcing thickness based on the reinforced safety margin until the preset range is met, and then generating the final opening reinforcing structure. The preset range can be 0-0.2.

[0088] Specifically, if the calculated reinforced safety margin meets the preset range, it indicates that the current single-side reinforcing structure can make the strength of the composite plate opening meet the requirements and no damage occurs, and thus the final opening reinforcing structure can be generated. If the reinforced safety margin does not meet the preset range, for example, the safety margin is too small or even negative, it indicates that the current single-side reinforcing thickness is insufficient and the stress at the opening is still too large, which has a risk of damage. At this time, the thickness of the single-side reinforcing structure needs to be adjusted. Increasing the reinforcing thickness can improve the bearing capacity of the structure and disperse the stress concentration at the hole edge, that is, the thickness to be increased can be determined according to the degree of deficiency of the safety margin. Then, the reinforced safety margin after adjusting the thickness is recalculated, and the judgment is performed again until the safety margin meets the preset range, and then the final opening reinforcing structure is generated.

[0089] The technical scheme of the embodiment of the present application can determine whether the initial strength of the unopened composite material plate meets the requirements through the safety margin, and quantitatively determine the strengthening bias based on the safety margin, thereby avoiding the blindness of the strengthening bias design and providing accurate parameter basis for subsequent strengthening structure design. By calculating the strengthening strain, the strain state of the unopened plate after strengthening can be accurately obtained, thereby avoiding the deviation of subsequent strength analysis due to the lack of strain data after strengthening. By combining the strengthening strain and the unopened hole edge strain for analysis, the actual strength of the opening strengthening structure can be accurately evaluated, thereby reducing the workload and improving the analysis efficiency.

[0090] Embodiment three

[0091] Figure 3 A structural schematic diagram of a composite material plate opening strength analysis device provided for the third embodiment of the present application is shown in FIG. 3. Figure 3 As shown in the figure, the device comprises: a strengthening bias calculation module 310, configured to calculate the safety margin of the unopened composite material plate, and determine the strengthening bias according to the safety margin when the safety margin is less than or equal to 0.

[0092] A strengthening strain calculation module 320, configured to calculate the strengthening strain of the unopened composite material plate in combination with the strengthening bias.

[0093] An opening strength analysis module 330, configured to calculate the unopened hole edge strain of the opening composite material plate according to a preset opening size, and perform composite material plate opening strength analysis according to the strengthening strain and the unopened hole edge strain.

[0094] Optionally, the strengthening bias calculation module 310 specifically comprises: a safety margin calculation unit, configured to: obtain the basic mechanical parameters of the unopened composite material plate, calculate the mid-surface force flow and the bending moment flow according to the basic mechanical parameters, and calculate the surface strain of the unopened composite material plate according to the mid-surface force flow and the bending moment flow, wherein the basic mechanical parameters include the line force, the bending moment, the shell element bias and the thickness of the laminated plate; perform strength checking on the composite material plate based on the surface strain by using a strain checking method, and calculate the safety margin.

[0095] Optionally, the strengthening bias calculation module 310 specifically comprises: a strengthening bias calculation unit, configured to: perform single-side strengthening on the hole edge according to the safety margin, and take the negative value of the safety margin and the original thickness as the single-side strengthening thickness; and take half of the single-side strengthening thickness as the strengthening bias.

[0096] Optionally, the strengthening strain calculation module 320 is specifically configured to: replace the shell element bias in the basic mechanical parameters with the strengthening bias to calculate the strengthened mid-surface force flow and the bending moment flow; and calculate the strengthening strain of the unopened composite material plate according to the strengthened mid-surface force flow and the bending moment flow.

[0097] Optionally, the opening strength analysis module 330 specifically comprises: an unstiffened hole edge strain calculation unit, configured to: obtain far-field stress of a hole edge according to a preset opening size, and calculate disturbance stress of the hole edge by using the Lekhnitskii method; and determine unstiffened hole edge strain of the opening composite material plate according to the far-field stress and the disturbance stress.

[0098] Optionally, the opening strength analysis module 330 specifically comprises: an opening strength analysis unit, configured to: calculate a hole edge stress concentration coefficient according to the stiffened strain and the unstiffened hole edge strain; calculate stiffened hole edge strain of the opening composite material plate according to the hole edge stress concentration coefficient in combination with surface strain; calculate principal strain according to the stiffened hole edge strain, and calculate a stiffening safety margin based on the principal strain; and perform opening strength analysis of the composite material plate according to the stiffening safety margin.

[0099] Optionally, the opening strength analysis unit is specifically configured to: determine whether the stiffening safety margin meets a preset range, and if yes, generate a final opening stiffening structure; otherwise, adjust a single-side stiffening thickness based on the stiffening safety margin until the stiffening safety margin meets the preset range, and generate the final opening stiffening structure.

[0100] The technical scheme of the embodiment of the present application can determine whether the initial strength of the unopened composite material plate meets the requirement through the safety margin, and quantitatively determine the stiffening offset based on the safety margin, thereby avoiding the blindness in the design of the stiffening offset and providing accurate parameter basis for subsequent stiffening structure design. By calculating the stiffening strain, the strain state of the unopened plate after stiffening can be accurately obtained, thereby avoiding the deviation in subsequent strength analysis due to the lack of strain data after stiffening. By combining the stiffening strain and the unstiffened hole edge strain for analysis, the actual strength of the opening stiffening structure can be accurately evaluated, thereby reducing the workload and improving the analysis efficiency.

[0101] The composite material plate opening strength analysis device provided in the embodiment of the present application can execute the composite material plate opening strength analysis method provided in any embodiment of the present application, and has the corresponding function modules and beneficial effects of the execution method.

[0102] Embodiment four

[0103] Figure 4A structural diagram of an electronic device 10 that can be used to implement embodiments of the present application is shown. The electronic device is intended to represent various forms of digital computers, such as laptops, desktops, tablets, personal digital assistants, servers, blade servers, mainframes, and other appropriate computers. The electronic device can also represent various forms of mobile devices, such as personal digital assistants, cellular telephones, smartphones, wearable devices (e.g., headsets, glasses, watches, etc.), and other similar computing devices. The components shown here, their connections and relationships, and their functions, are meant to be examples only, and are not meant to limit implementations of the present application described and / or claimed in this document.

[0104] As shown in Figure 4 The electronic device 10 includes at least one processor 11, and a memory, such as a read-only memory (ROM) 12, a random access memory (RAM) 13, etc., communicatively connected to the at least one processor 11, where the memory stores computer programs executable by the at least one processor. The processor 11 can perform various appropriate actions and processes according to the computer programs stored in the read-only memory (ROM) 12 or loaded into the random access memory (RAM) 13 from the storage unit 18. In the RAM 13, various programs and data required for the operation of the electronic device 10 can also be stored. The processor 11, the ROM 12, and the RAM 13 are connected to each other through a bus 14. An input / output (I / O) interface 15 is also connected to the bus 14.

[0105] Various components in the electronic device 10 are connected to the I / O interface 15, including an input unit 16, such as a keyboard, a mouse, etc., an output unit 17, such as various types of displays, speakers, etc., a storage unit 18, such as a magnetic disk, an optical disk, etc., and a communication unit 19, such as a network card, a modem, a wireless communication transceiver, etc. The communication unit 19 allows the electronic device 10 to exchange information / data with other devices through a computer network, such as the Internet, and / or various telecommunication networks.

[0106] The processor 11 can be various general and / or special purpose processing components with processing and computing capabilities. Some examples of the processor 11 include, but are not limited to, a central processing unit (CPU), a graphics processing unit (GPU), various special-purpose artificial intelligence (AI) computing chips, various processors running machine learning model algorithms, a digital signal processor (DSP), and any appropriate processor, controller, microcontroller, etc. The processor 11 performs various methods and processes described above, such as a composite material panel opening strength analysis method.

[0107] In some embodiments, a composite panel opening strength analysis method can be implemented as a computer program tangibly embodied in a computer readable storage medium, e.g., storage unit 18. In some embodiments, parts or all of the computer program can be loaded and / or installed onto electronic device 10 via, e.g., ROM 12 and / or communication unit 19. When the computer program is loaded onto RAM 13 and executed by processor 11, one or more steps of a composite panel opening strength analysis method as described above can be performed. Alternatively, in other embodiments, processor 11 can be configured to perform a composite panel opening strength analysis method by other means, e.g., with the aid of firmware.

[0108] Various implementations of the systems and techniques described above can be realized in digital electronic circuitry, integrated circuitry, specially designed application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), computer hardware, firmware, software, and / or combinations thereof. These various implementations can include implementation in one or more computer programs that are executable and / or interpretable on a programmable system including at least one programmable processor, which can be special or general purpose, coupled to receive data and instructions from, and to transmit data and instructions to, a storage system, at least one input device, and at least one output device.

[0109] Computer programs used to implement the methods of the application can be written in any combination of one or more programming languages. These computer programs can be provided to a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the computer program, when executed by the processor of the machine, implements the functions / acts specified in the flowcharts and / or block diagrams. The computer program can be executed entirely on a machine, partially on a machine, partially on a machine and partially on a remote machine or entirely on a remote machine or server.

[0110] In the context of the present application, a computer-readable storage medium can be a tangible medium that can contain or store a computer program for use by or in connection with an instruction execution system, apparatus, or device. A computer-readable storage medium can include, but is not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. Alternatively, a computer-readable storage medium can be a machine-readable signal medium. More specific examples of a machine-readable storage medium will include one or more lines of a program of instructions in a transitory signal, a portable computer diskette, 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 disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

[0111] To provide for interaction with a user, the systems and techniques described here can be implemented on an electronic device having a display device (e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor) for displaying information to the user and a keyboard and a pointing device (e.g., a mouse or a trackball) by which the user can provide input to the electronic device. Other kinds of devices can be used to provide for interaction with a user as well; for example, feedback provided to the user can be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback); and input from the user can be received in any form, including acoustic, speech, or tactile input.

[0112] The systems and techniques described here can be implemented in a computing system that includes a back end component (e.g., as a data server), or that includes a middleware component (e.g., an application server), or that includes a front end component (e.g., a user computer having a graphical user interface or a Web browser through which a user can interact with an implementation of the systems and techniques described here), or any combination of such back end, middleware, or front end components. The components of the system can be interconnected by any form or medium of digital data communication (e.g., a communication network). Examples of communication networks include a local area network (LAN), a wide area network (WAN), blockchain network, and the Internet.

[0113] The computing system can include clients and servers. A client and server are generally remote from each other and typically interact through a communication network. The relationship of client and server arises by virtue of computer programs running on the respective computers and having a client-server relationship to each other. The server can be a cloud server, also known as a cloud computing server or cloud host, which is a host product in the cloud computing service system, and solves the defects of large management difficulty and weak business scalability in traditional physical host and VPS service.

[0114] It should be understood that the various forms of flow shown above can be used to reorder, add or delete steps. For example, each step described in the present application can be executed in parallel, sequentially or in a different order, as long as the desired results of the technical solutions of the present application can be achieved, which is not limited herein.

[0115] The above detailed description does not constitute a limitation on the scope of protection of the present application. Those skilled in the art should understand that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present application shall be included in the scope of protection of the present application.

Claims

1. A method of analyzing the open-hole strength of a composite material panel, characterized in that, The method comprises the following steps: calculating the safety margin of the unopened composite material plate, and determining the reinforcing bias according to the safety margin when the safety margin is less than or equal to 0; calculating the reinforcing strain of the unopened composite material plate in combination with the reinforcing bias; calculating the un-reinforced hole edge strain of the opened composite material plate according to a preset opening size, and performing the opening strength analysis of the composite material plate according to the reinforcing strain and the un-reinforced hole edge strain.

2. The method of claim 1, wherein, The method for calculating the safety margin of the unopened composite material plate comprises the following steps: obtaining the basic mechanical parameters of the unopened composite material plate, calculating the mid-surface force flow and the bending moment flow according to the basic mechanical parameters, and calculating the surface strain of the unopened composite material plate according to the mid-surface force flow and the bending moment flow, wherein the basic mechanical parameters comprise the line force, the bending moment, the shell element bias and the thickness of the laminated plate; performing the strength check of the composite material plate by using the strain check method based on the surface strain, and calculating the safety margin.

3. The method of claim 2, wherein, The method for determining the reinforcing bias according to the safety margin comprises the following steps: performing the single-side reinforcement on the hole edge according to the safety margin, and taking the negative value of the safety margin and the original thickness as the single-side reinforcement thickness; taking half of the single-side reinforcement thickness as the reinforcing bias.

4. The method of claim 2, wherein, The method for calculating the reinforcing strain of the unopened composite material plate in combination with the reinforcing bias comprises the following steps: replacing the shell element bias in the basic mechanical parameters with the reinforcing bias to calculate the reinforced mid-surface force flow and the bending moment flow; calculating the reinforcing strain of the unopened composite material plate according to the reinforced mid-surface force flow and the bending moment flow.

5. The method of claim 1, wherein, The method for calculating the un-reinforced hole edge strain of the opened composite material plate according to a preset opening size comprises the following steps: obtaining the far-field stress of the hole edge according to the preset opening size, and calculating the hole edge disturbance stress by using the Lekhniski method; determining the un-reinforced hole edge strain of the opened composite material plate according to the far-field stress and the disturbance stress.

6. The method of claim 3, wherein, The method for performing the opening strength analysis of the composite material plate according to the reinforcing strain and the un-reinforced hole edge strain comprises the following steps: calculating the hole edge stress concentration coefficient according to the reinforcing strain and the un-reinforced hole edge strain; calculating the reinforced hole edge strain of the opened composite material plate according to the hole edge stress concentration coefficient in combination with the surface strain; calculating the principal strain according to the reinforced hole edge strain, calculating the reinforcing safety margin based on the principal strain, and performing the opening strength analysis of the composite material plate according to the reinforcing safety margin.

7. The method of claim 6, wherein, The method for performing the opening strength analysis of the composite material plate according to the reinforcing safety margin comprises the following steps: determining whether the reinforcing safety margin meets a preset range, and generating a final opening reinforcing structure if yes; otherwise, adjusting the single-side reinforcement thickness based on the reinforcing safety margin until the reinforcing safety margin meets the preset range, and generating the final opening reinforcing structure.

8. A device for analyzing the open strength of a composite material plate, characterized in that, The method comprises the following steps: a reinforcing bias calculation module is configured to calculate the safety margin of the unopened composite material plate, and determine the reinforcing bias according to the safety margin when the safety margin is less than or equal to 0; a reinforcing strain calculation module is configured to calculate the reinforcing strain of the unopened composite material plate in combination with the reinforcing bias; an opening strength analysis module is configured to calculate the un-reinforced hole edge strain of the opened composite material plate according to a preset opening size, and perform the opening strength analysis of the composite material plate according to the reinforcing strain and the un-reinforced hole edge strain.

9. An electronic device, comprising: The electronic device comprises: at least one processor; and a memory connected in communication with the at least one processor; wherein the memory stores a computer program capable of being executed by the at least one processor, and the computer program is executed by the at least one processor to enable the at least one processor to execute the method of any one of claims 1-7.

10. A computer storage medium, characterized in that, The computer storage medium stores computer instructions for causing the processor to implement the method of any one of claims 1-7 when executed.

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