Method and device for solving stress intensity factor of hole surface crack

Abstract

The invention provides a method and a device for solving a stress intensity factor of a hole surface crack based on a weight function. The method comprises the following steps: identifying a plurality of geometric parameters of a hole surface crack; determining a plurality of characteristic parameters influencing the stress intensity factor according to the plurality of geometric parameters; carrying out sensitivity analysis on the plurality of characteristic parameters; establishing a reference solution matrix according to a result of the sensitivity analysis; determining a weight function coefficient in a weight function formula through the reference solution matrix; the integral operation in the weight function formula solving process is converted into polynomial multiplication, so that a stress intensity factor solving formula is obtained; and substituting the weight function coefficient into a weight function formula, and obtaining stress intensity factors under different geometric parameter combinations in combination with a stress intensity factor solving formula.

Description

Technical Field

[0001] The present invention relates to the field of damage tolerance, and more particularly, to a method and device for solving the stress intensity factor of a crack on the surface of a hole. Background Art

[0002] Airworthiness regulations such as FAR33.70 / CCAR33.70 / CS-E 515 and other engine regulations clearly require that damage tolerance assessments must be carried out on the life-limiting components of civil engines. Machining defects on the surface of the disk holes may cause non-containment accidents of aero-turbine engines. For this reason, the FAA has issued Advisory Circular AC33.70-2, requiring probabilistic damage tolerance assessments to be carried out for machining defects on the surface of round holes. Crack growth analysis is an important part of probabilistic damage tolerance assessment, and the stress intensity factor is a key factor in crack growth analysis. Therefore, an accurate and efficient method for solving the stress intensity factor is of great significance.

[0003] The stress intensity factor is a measure of the stress field singularity in the region near the crack tip under the condition of small-scale yielding. Generally, methods for solving the stress intensity factor include the complex variable function method, the singular integral equation and integral transform method, the weight function method, etc. The most important numerical methods are the finite element method (FEM), as well as the boundary element method (BEM) and the boundary collocation method (BCM), etc. Among them, methods such as the complex variable function method can only solve the theoretical solutions of a limited number of stress intensity factors for simple geometric bodies, and the application scope is very limited. The finite element method requires certain modeling experience, and analysis needs to be carried out for each geometric configuration, and the calculation efficiency is low. The weight function method separates the geometric influence factors from the stress influence factors, is applicable to the solution of the stress intensity factor under different stress distributions, and has high solution efficiency, so it is widely used in engineering.

[0004] Although existing stress intensity factor manuals contain tables and formulas for solving the stress intensity factor of some geometric configurations, the application scope is limited. The engine structure is affected by temperature, pressure, centrifugal force, etc., and the stress situation is complex. For the stress intensity factor of a crack on the surface of a round hole, a solution model still needs to be developed independently. The stress intensity factor of a crack on the surface of a round hole belongs to the problem of solving three-dimensional stress intensity factors. Compared with two-dimensional problems, there are more geometric parameters affecting it. Therefore, the dimension and quantity of the reference solution matrix required for solving the weight function are large. If the number of data points in the reference solution matrix is too large, it will cause difficulties in matrix construction and reduce the subsequent solution efficiency. Summary of the Invention

[0005] The present invention content is provided to introduce some concepts in a simplified form that will be further described in the following specific embodiments. The present invention content is not intended to identify the key features or essential features of the claimed subject matter, nor is it intended to be used to help determine the scope of the claimed subject matter.

[0006] One of the objectives of the present invention is to provide a method and device for solving the stress intensity factor of a crack on the surface of a hole based on a weight function. Among them, aiming at the problems of many geometric parameters of the crack type on the surface of the hole, large dimensions and large quantity in establishing the reference solution matrix, through sensitivity analysis of geometric characteristic parameters, according to the results of sensitivity analysis, the density of sampling points is set according to the influence degree of characteristic parameters, so that the established reference solution matrix can be used for solving as accurately and efficiently as possible. On the other hand, the process of solving the stress intensity factor involves integrating the product of stress and weight function on the stress path, and this method further improves the efficiency of solving the stress intensity factor by transforming the integral operation into polynomial solving.

[0007] According to one aspect of the present disclosure, there is provided a method for solving the stress intensity factor of a crack on the surface of a hole based on a weight function, including: identifying a plurality of geometric parameters of the crack on the surface of the hole; determining a plurality of characteristic parameters that affect the stress intensity factor according to the plurality of geometric parameters; performing sensitivity analysis on the plurality of characteristic parameters; establishing a reference solution matrix according to the results of sensitivity analysis; determining the weight function coefficients in the weight function formula through the reference solution matrix; transforming the integral operation in the process of solving the weight function formula into polynomial multiplication to obtain a stress intensity factor solving formula; and substituting the weight function coefficients into the weight function formula and combining with the stress intensity factor solving formula to obtain the stress intensity factor under different combinations of geometric parameters.

[0008] In an embodiment of the present disclosure, establishing a reference solution matrix according to the results of sensitivity analysis further includes: respectively determining the sampling quantity of each characteristic parameter in the plurality of characteristic parameters according to the influence degree of the plurality of characteristic parameters on the stress intensity factor; determining the corresponding geometric configuration for each group of characteristic parameters corresponding to each characteristic parameter; and establishing a finite element mesh based on each geometric configuration and the sampling quantity of each characteristic parameter, and solving the stress intensity factor of each group of characteristic parameters by the finite element method, so as to construct a reference solution matrix.

[0009] In a further embodiment of the present disclosure, solving the stress intensity factor of each group of characteristic parameters by the finite element method to construct a reference solution matrix further includes: constructing a test matrix based on the stress intensity factor of each group of characteristic parameters; applying reference loads under uniform stress and linear stress conditions to the test matrix to obtain a plurality of shape factors; and constructing a reference solution matrix based on the plurality of shape factors.

[0010] In a further embodiment of the present disclosure, in the case of uniform stress, the corresponding reference stress intensity factor is And in the case of linear stress, the corresponding reference stress intensity factor Wherein, a is the crack length in the hole thickness direction; σ 0 is the unit stress; F r1, F r2 is the shape factor; and

[0011]

[0012] where c is the crack length in the width direction of the hole.

[0013] In another embodiment of the present disclosure, determining the weight function coefficients in the weight function formula by referring to the reference solution matrix further includes: interpolating the input geometric parameters in the reference solution matrix to obtain the corresponding shape factor by the interval linear interpolation method; and determining the weight function coefficients in the weight function formula based on the corresponding shape factor and by the following items: the corresponding reference stress intensity factor under the uniform stress condition; the corresponding reference stress intensity factor under the linear stress condition; and the geometric relationship derived from the weight function formula.

[0014] In a further embodiment of the present disclosure, determining the weight function coefficients in the weight function formula by referring to the reference solution matrix further includes: combining the corresponding reference stress intensity factor under the uniform stress condition, the corresponding reference stress intensity factor under the linear stress condition with the stress intensity factor in integral form, where the stress intensity factor in integral form is:

[0015]

[0016] where σ I (x) is the stress distribution on the crack surface; m(x,a) is the weight function formula.

[0017] In another embodiment of the present disclosure, converting the integral operation in the solution process of the weight function formula into polynomial multiplication to obtain the stress intensity factor solution formula further includes: polynomializing the stress intensity factor solution formula in the integral form along the c surface direction to obtain the stress intensity factor solution formula in polynomial form as:

[0018]

[0019]

[0020] where K c represents the stress intensity factor in the c direction; K ci represents the stress intensity factor corresponding to the X i term; C i represents the coefficient; width represents the width of the crack on the hole surface; m p represents the weight function formula, which is:

[0021]

[0022] where M 1c 、M2c and M 3c are the weight function coefficients of the weight function formula.

[0023] In another embodiment of the present disclosure, the plurality of geometric parameters include: width W, thickness t, hole offset distance B, hole diameter D, crack length a in the hole thickness direction, crack length c in the hole width direction, and crack offset surface distance T; and the plurality of characteristic parameters include a / c, D / t, B / W, T / t, a / T, and c / (B - D / 2).

[0024] According to another aspect of the present disclosure, there is provided a device for solving the stress intensity factor of a hole surface crack based on a weight function, including: a memory; a communication interface; and at least one processor communicatively coupled to the memory and the communication interface, the at least one processor being configured to: identify a plurality of geometric parameters of the hole surface crack; determine a plurality of characteristic parameters that affect the stress intensity factor according to the plurality of geometric parameters; perform a sensitivity analysis on the plurality of characteristic parameters; establish a reference solution matrix according to the results of the sensitivity analysis; determine the weight function coefficients in the weight function formula through the reference solution matrix; convert the integral operation in the process of solving the weight function formula into polynomial multiplication to obtain a stress intensity factor solving formula; and substitute the weight function coefficients into the weight function formula and combine with the stress intensity factor solving formula to obtain the stress intensity factor under different combinations of geometric parameters.

[0025] According to another aspect of the present disclosure, there is provided a non-transitory computer-readable medium storing computer-executable instructions, the computer-executable instructions causing the device for solving the stress intensity factor of a hole surface crack based on a weight function to: identify a plurality of geometric parameters of the hole surface crack; determine a plurality of characteristic parameters that affect the stress intensity factor according to the plurality of geometric parameters; perform a sensitivity analysis on the plurality of characteristic parameters; establish a reference solution matrix according to the results of the sensitivity analysis; determine the weight function coefficients in the weight function formula through the reference solution matrix; convert the integral operation in the process of solving the weight function formula into polynomial multiplication to obtain a stress intensity factor solving formula; and substitute the weight function coefficients into the weight function formula and combine with the stress intensity factor solving formula to obtain the stress intensity factor under different combinations of geometric parameters.

[0026] These and other features and advantages will become apparent by reading the following detailed description and referring to the associated drawings. It should be understood that the foregoing general description and the following detailed description are illustrative and do not limit the various aspects claimed. Description of the Drawings

[0027] To understand the manner in which the above-described features of the present invention can be used in detail, the above briefly summarized content can be described more specifically with reference to the embodiments, some aspects of which are shown in the accompanying drawings. However, it should be noted that the drawings only show certain typical aspects of the present invention and should not be considered as limiting its scope, as the description may allow other equally effective aspects.

[0028] Figure 1 is a schematic diagram of a hole surface crack model according to an embodiment of the present invention.

[0029] Figure 2 is a flowchart of a method for solving the stress intensity factor of a hole surface crack based on a weight function according to an embodiment of the present invention.

[0030] Figure 3 is a schematic diagram of the process of establishing a stress intensity factor solution model according to an embodiment of the present invention.

[0031] Figure 4a and Figure 4b is a schematic diagram of the comparison of stress intensity factors at different a / c ratios according to an embodiment of the present invention.

[0032] Figure 5 is a schematic diagram of the comparison error between the calculation model and the commercial software according to an embodiment of the present invention.

[0033] Figure 6 is a schematic diagram of a device for solving the stress intensity factor of a hole surface crack based on a weight function according to an embodiment of the present invention.

[0034] In the accompanying drawings, the drawings are not drawn to actual scale. Detailed Embodiments

[0035] Embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although some embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure can be implemented in various forms and should not be construed as limited to the embodiments set forth herein. Instead, these embodiments are provided to more thoroughly and completely understand the present disclosure. It should be understood that the drawings and embodiments of the present disclosure are for illustrative purposes only and are not used to limit the scope of protection of the present disclosure.

[0036] In the description of the present disclosure, it should be noted that unless otherwise specified, the meaning of "a plurality" is more than two; the orientation or positional relationships indicated by terms such as "upper", "lower", "left", "right", "inner", "outer", etc. are only for the convenience of describing the present disclosure and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present disclosure. In addition, terms such as "first", "second", "third", etc. are only used for descriptive purposes and cannot be construed as indicating or implying relative importance. "Vertical" is not strictly vertical, but within the allowable error range. "Parallel" is not strictly parallel, but within the allowable error range.

[0037] The orientation terms appearing in the following description are all the directions shown in the figures and do not limit the specific structure of the present disclosure. In the description of the present disclosure, it should also be noted that unless otherwise clearly specified and limited, the terms "mounted", "connected", and "coupled" 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 directly connected or indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the present disclosure can be understood according to specific circumstances.

[0038] Referring to "embodiments" herein means that the specific features, structures, or characteristics described in connection with the embodiments can be included in at least one embodiment of the present disclosure. The phrase appearing in various positions in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art explicitly and implicitly understand that the embodiments described herein can be combined with other embodiments.

[0039] In the description of the embodiments of the present disclosure, the term "and / or" is merely a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " herein generally represents an "or" relationship between the associated objects before and after.

[0040] Existing stress intensity factor manuals contain tables and formulas for solving stress intensity factors of some geometric configurations, but their application ranges are limited. Due to the influence of factors such as thermal stress and temperature on the engine structure, the stress conditions are complex, and for the stress intensity factor solution model of the hole surface crack type, it is still necessary to develop it independently.

[0041] The hole surface crack model is as Figure 1As shown, it may involve a total of seven geometric parameters, including: width W, thickness t, hole offset distance B, hole diameter D, crack length a in the hole thickness direction, crack length c in the hole width direction, and crack offset surface distance T. Additionally, with the center of the semi-ellipse as the origin, a represents the crack length on one side, and a1 represents the crack length on the other side. Correspondingly, the reference solution matrix required for solving the weight function has a large dimension and a large quantity. However, if there are too many data points in the reference solution matrix, it will cause difficulties in matrix construction and reduce the subsequent solution efficiency. Accordingly, the present disclosure proposes a method for solving the stress intensity factor of a surface crack of a hole based on the weight function. A reference solution matrix is established based on the sensitivity analysis of geometric characteristic parameters, and the calculation efficiency is further improved by converting the integral operation into a polynomial operation. The entire process can efficiently and accurately solve the stress intensity factor of the surface crack of the hole.

[0042] Figure 2 FIG. is a flowchart of a method for solving the stress intensity factor of a surface crack of a hole based on the weight function according to an embodiment of the present invention.

[0043] As Figure 2 shown in FIG., in step 202, multiple geometric parameters of the surface crack of the hole can be identified. Among them, the multiple geometric parameters may include, for example: width W, thickness t, hole offset distance B, hole diameter D, crack length a in the hole thickness direction, crack length c in the hole width direction, and crack offset surface distance T.

[0044] In step 204, multiple characteristic parameters that affect the stress intensity factor can be determined based on the multiple geometric parameters. Among them, the multiple characteristic parameters may include a / c, D / t, B / W, T / t, a / T, and c / (B - D / 2).

[0045] In step 206, a sensitivity analysis can be performed on the multiple characteristic parameters.

[0046] In step 208, a reference solution matrix can be established based on the results of the sensitivity analysis. Specifically, for example, the sampling quantity of each characteristic parameter among the multiple characteristic parameters can be determined according to the influence degree of the multiple characteristic parameters on the stress intensity factor. For each set of characteristic parameters corresponding to each characteristic parameter, the corresponding geometric configuration is determined, and a finite element mesh is established based on each geometric configuration and the sampling quantity of each characteristic parameter. The stress intensity factor of each set of characteristic parameters is solved by the finite element method, thereby constructing a reference solution matrix.

[0047] In a non-limiting embodiment, solving the stress intensity factor of each set of characteristic parameters by the finite element method to construct the reference solution matrix may further include: constructing a test matrix based on the stress intensity factor of each set of characteristic parameters, then applying reference loads under uniform stress and linear stress conditions to the test matrix to obtain a plurality of shape factors, and then constructing the reference solution matrix based on the plurality of shape factors.

[0048] Wherein, under the condition of uniform stress, the corresponding reference stress intensity factor is And under the condition of linear stress, the corresponding reference stress intensity factor Wherein, a is the crack length in the hole thickness direction; σ 0 is the unit stress; F r1 , F r2 is the shape factor; and

[0049]

[0050] Wherein, c is the crack length in the hole width direction.

[0051] In step 210, the weight function coefficient in the weight function formula can be determined through the reference solution matrix. Specifically, for example, geometric parameters can be input for interpolation in the reference solution matrix, and the corresponding shape factor can be obtained through the interval linear interpolation method. Then, based on the corresponding shape factor, and through the following items, the weight function coefficient in the weight function formula is determined: the reference stress intensity factor corresponding to the uniform stress condition; the reference stress intensity factor corresponding to the linear stress condition; and the geometric relationship derived from the weight function formula.

[0052] In a further non-limiting embodiment, determining the weight function coefficient in the weight function formula through the reference solution matrix may further include: combining the reference stress intensity factor corresponding to the uniform stress condition, the reference stress intensity factor corresponding to the linear stress condition with the stress intensity factor in integral form, where the stress intensity factor in integral form is:

[0053]

[0054] Wherein, σ I (x) is the crack surface stress distribution; m(x, a) is the weight function formula.

[0055] In step 212, the integral operation in the process of solving the weight function formula can be transformed into polynomial multiplication to obtain the stress intensity factor solution formula. Specifically, the stress intensity factor solution formula in integral form with respect to the c surface direction can be polynomialized to obtain the stress intensity factor solution formula in polynomial form as:

[0056]

[0057]

[0058] Among them, K c represents the stress intensity factor in the c direction; K ci represents the stress intensity factor corresponding to the X i term; C i represents a coefficient; width represents the width of the crack on the hole surface; m p represents the weight function formula, which is:

[0059]

[0060] Among them, M 1c 、M 2c and M 3c are the weight function coefficients of the weight function formula.

[0061] In step 214, the weight function coefficients can be substituted into the weight function formula, and combined with the stress intensity factor solution formula to obtain the stress intensity factors under different combinations of geometric parameters.

[0062] Figure 3 Fig. shows a schematic diagram of the process of establishing a stress intensity factor solution model according to an embodiment of the present invention, which can be applied to industries such as aerospace, for example.

[0063] In step 302, geometric parameters can be identified, including, for example, width W, thickness t, hole offset distance B, hole diameter D, crack length a in the hole thickness direction, crack length c in the hole width direction, and crack offset surface distance T, as Figure 1 shown in.

[0064] In step 304, geometric characteristic parameters that affect the stress intensity factor can be identified according to the above geometric parameters (i.e., Figure 2 the characteristic parameters in), such as a / c, D / t, B / W, T / t, a / T, and c / (B - D / 2).

[0065] In step 306, a sensitivity analysis can be performed on the characteristic parameters obtained in step 304. The specific steps are as follows:

[0066] In step 322, a test matrix for the stress intensity factor is constructed, where it is required that the sampling points of the test matrix have sufficient coverage.

[0067] In step 324, for example, a = 1 can be fixed, and different geometric parameters can be obtained by the ratios of different characteristic parameters a / c, D / t, B / W, T / t, a / T, c / (B - D / 2). Each set (a / c, D / t, B / W, T / t, a / T, c / (B - D / 2)) corresponds to a geometric configuration. For example, the range of characteristic parameters can be determined according to the specific application scenario. Considering that the possible form of the crack on the hole surface is generally a shallow surface crack, the range of the characteristic parameter a / c is determined to be [0.5, 4] (as shown in Table 1 below). According to this range, the sampling points can be further determined to be 0.5 and 4, and the sampling points of the remaining characteristic parameters can be selected similarly.

[0068] In step 326, for each geometric configuration, a finite element mesh is established, and each stress intensity factor is solved by the finite element method.

[0069] As a non - restrictive example, Figure 4a and Figure 4b shows the sensitivity analysis of a / c, and the same for the remaining characteristic parameters. Among them, Figure 4a shows the stress intensity factor in the c - direction under a uniform load, while Figure 4b shows the stress intensity factor in the c - direction under a linear load. In Figure 4a and Figure 4b , the ordinate Kc_S0 represents the stress intensity factor in the c - direction under a uniform stress, Kc_S1 represents the stress intensity factor in the c - direction under a linear stress, and the abscissa N represents the serial number of the sensitivity analysis case. Through the sensitivity analysis of each characteristic parameter, it is found that the characteristic parameters a / T, c / (B - D / 2), a / c, D / t have a greater impact on the stress intensity factor, while B / W, T / t have a smaller impact on the stress intensity factor.

[0070] In step 308, a reference solution matrix can be established according to the results of the above - mentioned sensitivity analysis. The sampling points of the reference solution matrix can be as shown in Table 1. Among them, for T / t and B / W with a smaller impact, sparser sampling points can be used, while for the remaining characteristic parameters, denser sampling points can be used.

[0071] Table 1 Data points for constructing the reference solution matrix

[0072]

[0073] Apply a reference load to the crack surface and solve it by the finite element method to obtain the corresponding stress intensity factors K r1 and K r2 . Specifically, the selection of the reference load for the reference solution matrix can be as follows:

[0074] (1) In the case of a uniform stress σ = 1, the corresponding reference stress intensity factor is:

[0075]

[0076] (2) Under linear stress , the corresponding reference stress intensity factor is:[[]]

[0077]

[0078] where K r1 , and K r2 are stress intensity factors; a is the crack size; σ 0 is the unit stress, i.e., 1; F r1 , and F r2 are shape factors, and Q can be expressed as:[[]]

[0079]

[0080] Since the K r1 , and K r2 under uniform stress and linear stress have been solved by the finite element method above, the shape factors F r1 and F r2 in the formula can be further obtained through the above formula, and then the reference solution matrix is formed by the shape factors under different geometric characteristic parameters.[[]]

[0081] On the other hand, in step 310, the calculation process of the weight function can be optimized, and the integral operation in the process of solving the weight function is transformed into polynomial multiplication. The specific process is as follows:[[]]

[0082] The stress intensity factor solution formula is as shown in formula (1):[[]]

[0083]

[0084] where σ I (x) is the crack face stress distribution, m(x,a) is the weight function, and the weight function formula is shown in formula (2). The following is the derivation in the c direction (surface direction, see Figure 1 ):[[]]

[0085]

[0086] where c represents the crack length; x represents the distance of the stress distribution path from the crack origin; M 1c , M 2c , and M 3c represent the coefficients of the weight function, which are related to the geometric dimensions of the cracked body, the crack shape, etc.[[]]

[0087] Assume that the stress distribution σ(X) = ∑C i X i , where Ci The polynomial fitting coefficients representing the stress distribution, setting the normalized coordinates

[0088] By setting Substituting into formula (2) to perform variable substitution on formula (1), the intermediate variable m can be obtained i It is:

[0089]

[0090] Further transform m i into polynomial form:

[0091]

[0092] For the formula (1) after variable substitution, the stress intensity factor in the c direction can be expressed as:

[0093]

[0094]

[0095] Among them, K ci represents the stress intensity factor corresponding to the x i term, and K c represents the stress intensity factor in the c direction; width is the width W.

[0096] In step 312, the coefficients of the weight function, that is, M 1c 、M 2c 、M 3c . Specifically, any geometric parameters can be input, transformed into characteristic parameters, and interpolated in the reference solution matrix obtained in the above step 308 to obtain the shape factor corresponding to the geometric characteristic parameters. For example, interpolation can be performed in the reference solution matrix constructed according to Table 1 (i.e., a five-dimensional matrix with the characteristic parameters a / T, a / c, D / t, c / (B - D / 2), T / t as dimensions), and the values in this five-dimensional matrix can be obtained through batch processing by finite element analysis.

[0097] As a non-limiting example, the interpolation can, for example, adopt the interval linear interpolation method. According to Table 1, it is necessary to perform linear interpolation in the five-dimensional space.

[0098] The specific solution process of the weight function coefficients is as follows:

[0099] First, substitute the uniformly distributed stress σ = 1 and its stress intensity factor into formula (1) to obtain equation (1).

[0100] Then, substitute the linear stress and its stress intensity factor Substitute into Equation (1) to obtain Equation (2).

[0101] In addition, perform a second-order derivative on Equation (2), that is, the weight function in the c direction satisfies the following geometric conditions:

[0102]

[0103] According to Equation (6), Equation (3) can be obtained:

[0104] M 2c = 3(7)

[0105] According to the above Equations (1) to (3), the weight function coefficients in the c direction can be obtained as:

[0106]

[0107]

[0108] Then, according to Equation (4) and the weight function coefficient formulas (7) to (9) obtained above, the stress intensity factors under different combinations of geometric parameters can be solved.

[0109] In Step 314, the stress intensity factor solution model obtained by the stress intensity factor solution method of the present disclosure can be compared with the finite element analysis results to carry out the verification of the stress intensity factor solution to verify the accuracy of the stress intensity factor solution model of the present disclosure.

[0110] Figure 5 The comparison error between the stress intensity factor solution model of the present disclosure and the finite element software is shown, and the error calculation formula is as follows:

[0111] Error = (SIF test - SIF FEM ) / SIF FEM (10)

[0112] Among them, SIF test represents the stress intensity factor result solved by Equation (4) established by the present disclosure; SIF FEM represents the stress intensity factor solved by the finite element method; Error is the relative error between the two.

[0113] In Figure 5 , error_Ka represents the relative error of the stress intensity factor in the a direction, while error_Kc represents the relative error of the stress intensity factor in the c direction. It can be seen from Figure 5 that the error is basically within 5%, and very few are in the range of 5% - 10%. Thus, the stress intensity factor solution model of the present disclosure can meet the error requirements.

[0114] Figure 6 FIG. 2 shows a block diagram of a stress intensity factor solving device for a hole surface crack based on a weight function according to an embodiment of the present invention. The device shows a general hardware environment in which the present invention can be applied according to an exemplary embodiment of the present invention. The device can be any machine configured to perform processing and / or computing, and can be, but is not limited to, a workstation, a server, a desktop computer, a laptop computer, a tablet computer, a personal digital assistant (PDA), a smart phone, or any combination thereof. The above system can be implemented in whole or at least in part by this device or a similar device or system.

[0115] The device may include components that can be connected to or communicate with the bus 620 via one or more communication interfaces 630. For example, the device may include a bus 620, a processor 605, a memory 610, a communication interface 630, and so on.

[0116] The processor 605 can be any type of processor, and can include, but is not limited to, a general-purpose processor and / or a special-purpose processor (such as a special processing chip), a smart hardware device (such as a general-purpose processor, a DSP, a CPU, a microcontroller, an ASIC, an FPGA, a programmable logic device, discrete gate or transistor logic components, discrete hardware components, or any combination thereof). In some cases, the processor 605 can be configured to operate the memory array using a memory controller. In other cases, the memory controller (not shown) can be integrated into the processor 605. The processor 605 is responsible for managing the bus 620 and general processing, including executing software 615 stored in the memory 610. The processor 605 can also be configured to perform various functions related to solving the stress intensity factor of the hole surface crack based on the weight function described herein. For example, the processor 605 can be configured to: identify a plurality of geometric parameters of the hole surface crack; determine a plurality of characteristic parameters that affect the stress intensity factor according to the plurality of geometric parameters; perform a sensitivity analysis on the plurality of characteristic parameters; establish a reference solution matrix according to the results of the sensitivity analysis; determine the weight function coefficients in the weight function formula through the reference solution matrix; convert the integral operation in the process of solving the weight function formula into a polynomial multiplication to obtain a stress intensity factor solving formula; and substitute the weight function coefficients into the weight function formula and combine the stress intensity factor solving formula to obtain the stress intensity factor under different geometric parameter combinations.

[0117] The memory 610 can be any storage device capable of implementing data storage. The memory 610 may include, but is not limited to, disk drives, optical storage devices, solid-state memories, floppy disks, hard disks, magnetic tapes, or any other magnetic medium, optical discs, or any other optical medium, ROM (Read-Only Memory), RAM (Random Access Memory), cache memory, and / or any other memory chip or cartridge, and / or any other medium from which a computer can read data, instructions, and / or code. The memory 610 can store computer-executable software 615 including computer-readable instructions that, when executed, cause the processor to perform the various functions described herein. The memory 610 can have various data / instructions / codes for implementing the various functions related to the aeroengine thrust management design described herein.

[0118] The software 615 can be stored in the memory 610 and includes, but is not limited to, an operating system, one or more applications, drivers, and / or other data and code. Instructions for performing the various functions described herein can be included in one or more applications, and the components of the device can be implemented by the processor 605 reading and executing the instructions of one or more applications. In some cases, the software 615 may not be directly executable by the processor, but can (e.g., when compiled and executed) cause the computer to perform the various functions related to the technical publication compilation management described herein.

[0119] The stress intensity factor solving method and device for the hole surface crack based on the weight function of the present invention are described above. Compared with the solutions in the prior art, the present invention can improve the construction efficiency of the reference solution matrix by optimizing the process of establishing the reference solution matrix. In addition, by interpolating the optimized reference solution matrix, the interpolation efficiency during the solving process can be improved. Furthermore, by converting the integral operation in the weight function solving process into polynomial multiplication, the stress intensity factor solving efficiency can be further improved.

[0120] The above-described content includes examples of aspects of the claimed subject matter. Of course, it is not possible to describe every conceivable combination of components or methods for the purpose of depicting the claimed subject matter, but one of ordinary skill in the art should recognize that many further combinations and permutations of the claimed subject matter are possible. Thus, the disclosed subject matter is intended to cover all such alterations, modifications, and variations that fall within the spirit and scope of the appended claims.

Claims

1. A method for solving the stress intensity factor of a crack on the surface of a hole based on a weight function, characterized in that, it includes: identifying a plurality of geometric parameters of the crack on the surface of the hole; determining a plurality of characteristic parameters that affect the stress intensity factor according to the plurality of geometric parameters; performing a sensitivity analysis on the plurality of characteristic parameters; establishing a reference solution matrix according to the results of the sensitivity analysis; determining the weight function coefficients in the weight function formula through the reference solution matrix; converting the integral operation in the process of solving the weight function formula into a polynomial multiplication to obtain a stress intensity factor solving formula; and substituting the weight function coefficients into the weight function formula and combining with the stress intensity factor solving formula to obtain the stress intensity factors under different combinations of geometric parameters.

2. The method according to claim 1, characterized in that, establishing a reference solution matrix according to the results of the sensitivity analysis further includes: respectively determining the sampling number of each characteristic parameter in the plurality of characteristic parameters according to the influence degree of the plurality of characteristic parameters on the stress intensity factor; determining the corresponding geometric configuration for each group of characteristic parameters corresponding to each characteristic parameter; and establishing a finite element mesh based on each geometric configuration and the sampling number of each characteristic parameter, and solving the stress intensity factor of each group of characteristic parameters by the finite element method, thereby constructing a reference solution matrix.

3. The method according to claim 2, characterized in that, solving the stress intensity factor of each group of characteristic parameters by the finite element method to construct a reference solution matrix further includes: constructing a test matrix based on the stress intensity factors of each group of characteristic parameters; applying reference loads under uniform stress and linear stress conditions to the test matrix to obtain a plurality of shape factors; and constructing the reference solution matrix based on the plurality of shape factors.

4. The method according to claim 3, characterized in that, In the case of the uniform stress, the corresponding reference stress intensity factor is and In the case of the linear stress, the corresponding reference stress intensity factor where a is the crack length in the thickness direction of the hole; σ 0 is the unit stress; F r1 , F r2 is the shape factor; and where c is the crack length in the hole width direction.

5. The method according to claim 1, characterized in that, determining the weight function coefficients in the weight function formula through the reference solution matrix further includes: interpolating the input geometric parameters in the reference solution matrix and obtaining the corresponding shape factors by the interval linear interpolation method; and determining the weight function coefficients in the weight function formula based on the corresponding shape factors and through the following items: the corresponding reference stress intensity factor under uniform stress conditions; the corresponding reference stress intensity factor under linear stress conditions; and the geometric relationship derived from the weight function formula.

6. The method according to claim 5, characterized in that, determining the weight function coefficients in the weight function formula through the reference solution matrix further includes: combining the corresponding reference stress intensity factor under uniform stress conditions, the corresponding reference stress intensity factor under linear stress conditions with the stress intensity factor in integral form, where the stress intensity factor in integral form is: where, σ I (x) is the stress distribution on the crack surface; m(x,a) is the weight function formula.

7. The method according to claim 1, characterized in that, converting the integral operation in the process of solving the weight function formula into a polynomial multiplication to obtain a stress intensity factor solving formula further includes: Polynomialize the stress intensity factor solution formula in the form of surface direction integration of c to obtain the stress intensity factor solution formula in polynomial form as follows: Among them, K c represents the stress intensity factor in the c direction; K ci represents the stress intensity factor corresponding to the X i term; C i represents a coefficient; width represents the width of the surface crack of the hole; m p represents the weight function formula, which is: Among them, M 1c , M 2c and M 3c are the weight function coefficients of the weight function formula.

8. The method according to claim 1, characterized in that the multiple geometric parameters include: width W, thickness t, hole offset distance B, hole diameter D, crack length a in the hole thickness direction, crack length c in the hole width direction, and crack offset surface distance T; and the multiple characteristic parameters include a / c, D / t, B / W, T / t, a / T, and c / (B - D / 2).

9. A device for solving the stress intensity factor of a crack on the hole surface based on a weight function, characterized in that it includes: a memory; a communication interface; and at least one processor communicatively coupled to the memory and the communication interface, the at least one processor being configured to: identify multiple geometric parameters of the crack on the hole surface; determine multiple characteristic parameters affecting the stress intensity factor according to the multiple geometric parameters; perform a sensitivity analysis on the multiple characteristic parameters; establish a reference solution matrix according to the results of the sensitivity analysis; determine the weight function coefficients in the weight function formula through the reference solution matrix; convert the integral operation in the process of solving the weight function formula into polynomial multiplication to obtain the stress intensity factor solution formula; and substitute the weight function coefficients into the weight function formula and combine the stress intensity factor solution formula to obtain the stress intensity factors under different combinations of geometric parameters.

10. A non-transitory computer-readable medium storing computer-executable instructions, the computer-executable instructions, when executed by a device for solving the stress intensity factor of a crack on the hole surface based on a weight function, cause the device for solving the stress intensity factor of a crack on the hole surface based on a weight function to: identify multiple geometric parameters of the crack on the hole surface; determine multiple characteristic parameters affecting the stress intensity factor according to the multiple geometric parameters; perform a sensitivity analysis on the multiple characteristic parameters; establish a reference solution matrix according to the results of the sensitivity analysis; determine the weight function coefficients in the weight function formula through the reference solution matrix; convert the integral operation in the process of solving the weight function formula into polynomial multiplication to obtain the stress intensity factor solution formula; and substitute the weight function coefficients into the weight function formula and combine the stress intensity factor solution formula to obtain the stress intensity factors under different combinations of geometric parameters.

Images