Method and device for calculating fracture toughness of SMAs, terminal and storage medium

Abstract

The invention provides a method and device for calculating the fracture toughness of SMAs, a terminal and a storage medium. The method comprises the following steps: performing a crack propagation test on SMAs to be tested at a preset temperature, and determining an elastic component increment and a non-elastic component increment under a load-displacement curve from a previous period to a current period; according to the elastic component increment and the inelastic component increment, the J integral of the SMAs to be measured in the current period is calculated; the fracture toughness value of the to-be-tested SMAs is determined according to the J integral of the to-be-tested SMAs, the fracture toughness value of the to-be-tested SMAs can be determined, and the problem that in the prior art, load test setting and data processing are needed for calculation of the fracture toughness of the SMAs is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of metal fatigue crack analysis, and in particular to a calculation method, device, terminal and storage medium for the fracture toughness of SMAs. Background Art

[0002] Nickel-titanium (NiTi) shape memory alloys (SMAs) are smart materials with characteristic deformation responses to thermal stimuli. This deformation originates from a first-order displacement-reversible solid-solid phase transition, that is, from high-temperature austenite to low-temperature martensite. Repeated cyclic phase transitions lead to the gradual accumulation of dislocations. The areas that do not undergo austenite-to-martensite transformation reduce the ability of SMAs to deform according to external stimuli. Potential microcracks will eventually lead to failure or fracture after a sufficient number of cycles.

[0003] Compared with traditional structural metals, the fracture behavior of SMAs is more complex due to the presence of austenite to martensite phase transformation, orientation and reorientation of martensitic variants, the possibility of overload and transformation-induced plasticity, and thermo-mechanical coupling related to latent heat. In the prior art, the fracture characteristics of SMAs can be measured using full-field displacement data obtained by digital image correlation, which requires relatively complex test setup and strict post-processing of full-field data, resulting in cumbersome operation. Summary of the invention

[0004] The embodiments of the present invention provide a method, device, terminal and storage medium for calculating the fracture toughness of SMAs, so as to solve the problem in the prior art that the calculation of the fracture toughness of SMAs requires load test setting and data processing.

[0005] In a first aspect, an embodiment of the present invention provides a method for calculating the fracture toughness of SMAs, comprising:

[0006] A crack growth test is performed on the SMAs to be tested at a preset temperature to determine the increment of elastic components and the increment of inelastic components under the load-displacement curve from the previous cycle to the current cycle;

[0007] Calculating the J integral of the SMAs to be tested in the current cycle according to the elastic component increment and the inelastic component increment;

[0008] The fracture toughness value of the SMAs to be tested is determined based on the J-integral of the SMAs to be tested.

[0009] In a possible implementation, determining the elastic component increment and the inelastic component increment under the load-displacement curve from the previous cycle to the current cycle includes:

[0010] according to Determine the elastic component increment and the inelastic component increment under the load-displacement curve from the previous cycle to the current cycle;

[0011] in, represents the elastic component increment under the load-displacement curve from the (i-1)th cycle to the i-th cycle in the crack growth test, P i represents the load applied to the SMAs to be tested in the i-th cycle of the crack growth test, P i-1 represents the load applied to the SMAs to be tested in the (i-1)th cycle of the crack growth test, represents the elastic displacement component in the i-th cycle of the crack growth test, represents the elastic displacement component in the (i-1)th cycle of the crack growth test, C i represents the unloading elastic compliance in the crack growth test, represents the inelastic component increment under the load-displacement curve from the (i-1)th cycle to the i-th cycle in the crack growth test, represents the inelastic displacement component in the i-th cycle of the crack growth test, represents the inelastic displacement component in the (i-1)th cycle of the crack growth test, δ i represents the total displacement component in the i-th cycle in the crack growth test.

[0012] In a possible implementation, calculating the J-integral of the SMAs to be tested in the current cycle according to the elastic component increment and the inelastic component increment includes:

[0013] Calculating the elastic component of the J-integral of the SMAs to be tested according to the elastic component increment;

[0014] Calculating the inelastic component of the J-integral of the SMAs to be tested according to the inelastic component increment;

[0015] The J-integral of the SMAs to be measured is calculated based on the elastic component of the J-integral and the inelastic component of the J-integral.

[0016] In a possible implementation, calculating the elastic component of the J-integral of the SMAs to be tested according to the elastic component increment includes:

[0017] according to Calculate the elastic component of the J-integral of the SMAs to be tested;

[0018] in, represents the elastic component of the J-integral of the SMAs to be measured in the ith week, represents the elastic component of the J-integral of the (i-1)th weekly SMAs to be measured, represents the elastic-plastic factor of the (i-1)th period, B represents the thickness of the SMAs to be tested, and b i-1 represents the length of the unruptured ligament on the SMAs to be measured at the (i-1)th week, represents the geometric correlation factor, a i represents the crack depth on the SMAs to be measured in the (i-1)th week, a i-1 represents the crack depth on the SMAs to be measured in the (i-1)th week.

[0019] In one possible implementation, The method of determining

[0020]

[0021] Where W represents the width of the SMAs to be measured;

[0022] The method of determining

[0023]

[0024] In a possible implementation, the calculating the inelastic component of the J-integral of the SMAs to be tested according to the inelastic component increment includes:

[0025] according to Calculate the inelastic component of the J-integral of the SMAs to be tested;

[0026] in, represents the inelastic component of the J-integral of the SMAs to be measured in the ith week, represents the inelastic component of the J-integral of the (i-1)th weekly SMAs to be measured, represents the inelastic plastic factor of the (i-1)th period, represents the geometric correlation factor.

[0027] In one possible implementation, The method of determining

[0028]

[0029] The method of determining

[0030]

[0031] In a second aspect, an embodiment of the present invention provides a device for calculating the fracture toughness of SMAs, comprising:

[0032] A calculation module, for performing a crack growth test on the SMAs to be tested at a preset temperature, and determining an elastic component increment and an inelastic component increment under a load-displacement curve from a previous cycle to a current cycle;

[0033] The calculation module is further used to calculate the J integral of the SMAs to be tested in the current cycle according to the elastic component increment and the inelastic component increment;

[0034] A processing module is used to determine the fracture toughness value of the SMAs to be tested according to the J-integral of the SMAs to be tested.

[0035] In a third aspect, an embodiment of the present invention provides a terminal comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, the steps of the method for calculating the fracture toughness of SMAs as described in the first aspect or any possible implementation of the first aspect are implemented.

[0036] In a fourth aspect, an embodiment of the present invention provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the method for calculating the fracture toughness of SMAs as described in the first aspect or any possible implementation method of the first aspect are implemented.

[0037] The embodiment of the present invention provides a calculation method, device, terminal and storage medium of the fracture toughness of SMAs. By performing a crack extension test on the SMAs to be tested at a preset temperature, the elastic component increment and the inelastic component increment under the load-displacement curve from the previous cycle to the current cycle are determined; according to the elastic component increment and the inelastic component increment, the J-integral of the SMAs to be tested in the current cycle is calculated; according to the J-integral of the SMAs to be tested, the fracture toughness value of the SMAs to be tested is determined, thereby realizing the determination of the fracture toughness value of the SMAs to be tested, and solving the problem in the prior art that the calculation of the fracture toughness of SMAs requires load test setting and data processing. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0039] Figure 1 is a flow chart of the implementation of the method for calculating the fracture toughness of SMAs provided in an embodiment of the present invention;

[0040] Figure 2is a schematic diagram of a JR curve provided by an embodiment of the present invention;

[0041] Figure 3 is a schematic structural diagram of a device for calculating the fracture toughness of SMAs provided in an embodiment of the present invention;

[0042] Figure 4 is a schematic diagram of a terminal provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0043] In the following description, specific details such as specific system structures, technologies, etc. are provided for the purpose of illustration rather than limitation, so as to provide a thorough understanding of the embodiments of the present invention. However, it should be clear to those skilled in the art that the present invention may be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to prevent unnecessary details from obstructing the description of the present invention.

[0044] In order to make the purpose, technical solutions and advantages of the present invention more clear, specific embodiments will be described below in conjunction with the accompanying drawings.

[0045] Figure 1 A flow chart of a method for calculating the fracture toughness of SMAs provided in an embodiment of the present invention is described in detail as follows:

[0046] Step 101 , performing a crack growth test on the SMAs to be tested at a preset temperature, and determining the elastic component increment and the inelastic component increment under the load-displacement curve from the previous cycle to the current cycle.

[0047] The crack extension test in this embodiment measures the fracture toughness of conventional tough materials and extends to the apparent elastic property changes caused by martensitic transformation or martensitic orientation. It relies on the ASTM standard method, which applies loads to the SMAs to be tested at different temperatures to perform isothermal fracture tests, which can also be called isothermal load-displacement tests. Based on the concept of elastic-plastic fracture mechanics, the J integral is used as the fracture criterion.

[0048] During crack growth tests, the crack length of the SMAs being tested changes.

[0049] The SMAs to be tested may be NiTi SMAs to be tested.

[0050] In one embodiment, determining the elastic component increment and the inelastic component increment under the load-displacement curve from the previous cycle to the current cycle may include:

[0051] according to Determine the elastic component increment and the inelastic component increment under the load-displacement curve from the previous cycle to the current cycle;

[0052] in, represents the elastic component increment under the load-displacement curve from the (i-1)th cycle to the i-th cycle in the crack growth test, P i represents the load applied to the SMAs in the i-th cycle of the crack growth test, P i-1 represents the load applied to the SMAs in the (i-1)th cycle of the crack growth test, represents the elastic displacement component in the i-th cycle of the crack growth test, represents the elastic displacement component in the (i-1)th cycle of the crack growth test, C i represents the unloading elastic compliance in the crack growth test, represents the inelastic component increment under the load-displacement curve from the (i-1)th cycle to the i-th cycle in the crack growth test, represents the inelastic displacement component in the i-th cycle of the crack growth test, represents the inelastic displacement component in the (i-1)th cycle of the crack growth test, δ i represents the total displacement component in the i-th cycle in the crack growth test.

[0053] Step 102, calculating the J-integral of the SMAs to be tested in the current cycle according to the elastic component increment and the inelastic component increment.

[0054] In one embodiment, calculating the J-integral of the SMAs to be tested in the current cycle according to the elastic component increment and the inelastic component increment may include:

[0055] Calculate the elastic component of the J-integral of the SMAs to be tested based on the elastic component increment;

[0056] Calculate the inelastic component of the J-integral of the SMAs to be tested according to the inelastic component increment;

[0057] The J-integral of the SMAs to be tested is calculated based on the elastic component of the J-integral and the inelastic component of the J-integral.

[0058] Optionally, the elastic component of the J-integral of the SMAs to be tested is calculated based on the elastic component increment, including:

[0059] according to Calculate the elastic component of the J-integral of the SMAs to be tested;

[0060] in, represents the elastic component of the J-integral of the SMAs to be measured in the ith week, represents the elastic component of the J-integral of the (i-1)th weekly SMAs to be measured, represents the elastic-plastic factor of the (i-1)th period, B represents the thickness of the SMAs to be tested, and b i-1 represents the length of the unruptured ligament on the SMAs to be measured at the (i-1)th week, represents the geometric correlation factor, a i represents the crack depth on the SMAs to be measured in the (i-1)th week, a i-1 represents the crack depth on the SMAs to be measured in the (i-1)th week.

[0061] Based on the inelastic component increment, the inelastic component of the J-integral of the SMAs to be tested is calculated, including:

[0062] according to Calculate the inelastic component of the J-integral of the SMAs to be tested;

[0063] in, represents the inelastic component of the J-integral of the SMAs to be measured in the ith week, represents the inelastic component of the J-integral of the (i-1)th weekly SMAs to be measured, represents the inelastic plastic factor of the (i-1)th period, represents the geometric correlation factor.

[0064] In this embodiment, calculating the J-integral of the SMAs to be tested according to the elastic component of the J-integral and the inelastic component of the J-integral may include:

[0065] The sum of the elastic component of the J-integral and the inelastic component of the J-integral is calculated, and the calculated sum is used as the J-integral of the SMAs to be tested. The J-integral of the SMAs to be tested is the J-integral of the i-th cycle. Similarly, the J-integral of each subsequent cycle can be calculated using the above calculation method.

[0066] In the process of calculating the elastic and inelastic components of the J-integral of the SMAs to be tested, the elastic-plastic factor can be calculated based on the unruptured ligaments and widths of the SMAs to be tested.

[0067] In one embodiment, The method of determining

[0068]

[0069] Where W represents the width of the SMAs to be measured.

[0070] For the plasticity factor of conventional ductile materials, both phase transformation and plasticity are shear-driven processes, and the phase transformation shrinkage has little effect on the overall fracture toughening enhancement of the tested SMAs.

[0071] The method of determining

[0072]

[0073] It should be noted that the calculation of the geometric correlation factor depends on the elastic plasticity factor. In this embodiment, The method of determining

[0074] The method of determining

[0075] Step 103, determining the fracture toughness value of the SMAs to be tested according to the J-integral of the SMAs to be tested.

[0076] After determining the J integral of the SMAs to be tested, the change in crack depth of the SMAs to be tested from the 1st cycle to the i-th cycle is calculated, for example, Δa. The JR curve can be constructed based on the J integral and Δa of the SMAs to be tested, and the JR curve is essentially a power law that applies to the data of J and Δa. To determine the fracture toughness value of the SMAs to be tested, follow the ASTM E1820 procedure.

[0077] See also Figure 2 The JR curve shown. First, draw a construction line from the origin with a slope of 2σ Y , σ Y Represents the effective yield strength, which is the average of the critical stress and the ultimate tensile strength. The critical stress represents the stress or orientation required to initiate a phase transformation, which depends on whether the material is in an austenitic or adaptive martensitic state under zero load. For temperatures above the martensite stop, the critical stress is the yield stress of the martensite. Then two parallel exclusion lines are drawn at the abscissa 0.15mm and 1.5mm, and the data points of J-Δa between the two exclusion lines are plotted, and a power law regression is fitted, where the curve is the regression line and the data corresponding to the circle are the data points of Δa. Then draw an offset line parallel to the construction line, which intersects the abscissa at 0.2mm. The intersection of the offset line at 0.2mm and the regression line is the critical value of the J integral. If the thickness requirements of the SMAs to be tested are met, the remaining intermediate values ​​can be regarded as size-independent fracture toughness values. The thickness requirement here is B>10J IC / σ Y , J IC represents the critical value of the J-integral.

[0078] The embodiment of the present invention conducts a crack extension test on the SMAs to be tested at a preset temperature to determine the elastic component increment and the inelastic component increment under the load-displacement curve from the previous cycle to the current cycle; calculates the J-integral of the SMAs to be tested in the current cycle according to the elastic component increment and the inelastic component increment; determines the fracture toughness value of the SMAs to be tested according to the J-integral of the SMAs to be tested, thereby achieving the determination of the fracture toughness value of the SMAs to be tested, which solves the problem in the prior art that the calculation of the fracture toughness of SMAs requires load test setting and data processing.

[0079] It should be understood that the order of execution of the steps in the above embodiment does not necessarily mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiment of the present invention.

[0080] The following is an embodiment of the device of the present invention. For details not described in detail therein, reference may be made to the corresponding method embodiment described above.

[0081] Figure 3 The schematic diagram of the structure of the calculation device of the fracture toughness of SMAs provided by the embodiment of the present invention is shown. For the convenience of explanation, only the part related to the embodiment of the present invention is shown, which is described in detail as follows:

[0082] like Figure 3 As shown, the calculation device 3 for the fracture toughness of SMAs includes: a calculation module 31 and a processing module 32 .

[0083] A calculation module 31 is used to perform a crack growth test on the SMAs to be tested at a preset temperature to determine the elastic component increment and the inelastic component increment under the load-displacement curve from the previous cycle to the current cycle;

[0084] The calculation module 31 is further used to calculate the J integral of the SMAs to be tested in the current cycle according to the elastic component increment and the inelastic component increment;

[0085] The processing module 32 is used to determine the fracture toughness value of the SMAs to be tested according to the J-integral of the SMAs to be tested.

[0086] In a possible implementation, when the calculation module 31 determines the elastic component increment and the inelastic component increment under the load-displacement curve from the previous cycle to the current cycle, it is used to:

[0087] according to Determine the elastic component increment and the inelastic component increment under the load-displacement curve from the previous cycle to the current cycle;

[0088] in, represents the elastic component increment under the load-displacement curve from the (i-1)th cycle to the i-th cycle in the crack growth test, P i represents the load applied to the SMAs in the i-th cycle of the crack growth test, P i-1 represents the load applied to the SMAs in the (i-1)th cycle of the crack growth test, represents the elastic displacement component in the i-th cycle of the crack growth test, represents the elastic displacement component in the (i-1)th cycle of the crack growth test, C i represents the unloading elastic compliance in the crack growth test, represents the inelastic component increment under the load-displacement curve from the (i-1)th cycle to the i-th cycle in the crack growth test, represents the inelastic displacement component in the i-th cycle of the crack growth test, represents the inelastic displacement component in the (i-1)th cycle of the crack growth test, δ i represents the total displacement component in the i-th cycle in the crack growth test.

[0089] In a possible implementation, the calculation module 31 calculates the J-integral of the SMAs to be measured in the current cycle according to the elastic component increment and the inelastic component increment, and is used to:

[0090] Calculate the elastic component of the J-integral of the SMAs to be tested based on the elastic component increment;

[0091] Calculate the inelastic component of the J-integral of the SMAs to be tested according to the inelastic component increment;

[0092] The J-integral of the SMAs to be tested is calculated based on the elastic component of the J-integral and the inelastic component of the J-integral.

[0093] In a possible implementation, when the calculation module 31 calculates the elastic component of the J-integral of the SMAs to be measured according to the elastic component increment, it is used to:

[0094] according to Calculate the elastic component of the J-integral of the SMAs to be tested;

[0095] in, represents the elastic component of the J-integral of the SMAs to be measured in the ith week, represents the elastic component of the J-integral of the (i-1)th weekly SMAs to be measured, represents the elastic-plastic factor of the (i-1)th period, B represents the thickness of the SMAs to be tested, and b i-1 represents the length of the unruptured ligament on the SMAs to be measured at the (i-1)th week, represents the geometric correlation factor, a i represents the crack depth on the SMAs to be measured in the (i-1)th week, a i-1 represents the crack depth on the SMAs to be measured in the (i-1)th week.

[0096] In a possible implementation, the calculation module 31 determines When, according to

[0097]

[0098] Where W represents the width of the SMAs to be measured;

[0099] In a possible implementation, the calculation module 31 determines When, according to

[0100]

[0101] In a possible implementation, when the calculation module 31 calculates the inelastic component of the J-integral of the SMAs to be tested according to the inelastic component increment, it is used to:

[0102] according to Calculate the inelastic component of the J-integral of the SMAs to be tested;

[0103] in, represents the inelastic component of the J-integral of the SMAs to be measured in the ith week, represents the inelastic component of the J-integral of the (i-1)th weekly SMAs to be measured, represents the inelastic plastic factor of the (i-1)th period, represents the geometric correlation factor.

[0104] In a possible implementation, the calculation module 31 determines Time Based

[0105]

[0106] In a possible implementation, the calculation module 31 determines Time Based

[0107]

[0108] The above-mentioned device for calculating the fracture toughness of SMAs performs a crack extension test on the SMAs to be tested at a preset temperature, and the calculation module determines the elastic component increment and the inelastic component increment under the load-displacement curve from the previous cycle to the current cycle; according to the elastic component increment and the inelastic component increment, the calculation module calculates the J-integral of the SMAs to be tested in the current cycle; according to the J-integral of the SMAs to be tested, the processing module determines the fracture toughness value of the SMAs to be tested, thereby realizing the determination of the fracture toughness value of the SMAs to be tested, which solves the problem in the prior art that the calculation of the fracture toughness of SMAs requires load test setting and data processing.

[0109] Figure 4 is a schematic diagram of a terminal provided by an embodiment of the present invention. Figure 4 As shown, the terminal 4 of this embodiment includes: a processor 40, a memory 41, and a computer program 42 stored in the memory 41 and executable on the processor 40. When the processor 40 executes the computer program 42, the steps in the above-mentioned calculation method of the fracture toughness of each SMA are implemented, for example Figure 1 Alternatively, when the processor 40 executes the computer program 42, the functions of each module / unit in the above-mentioned device embodiments are realized, for example Figure 3 Functions of the modules / units 31 to 32 are shown.

[0110] Exemplarily, the computer program 42 may be divided into one or more modules / units, which are stored in the memory 41 and executed by the processor 40 to implement the present invention. The one or more modules / units may be a series of computer program instruction segments capable of implementing specific functions, which are used to describe the execution process of the computer program 42 in the terminal 4. For example, the computer program 42 may be divided into Figure 3 Modules / units 31 to 32 are shown.

[0111] The terminal 4 may include, but is not limited to, a processor 40 and a memory 41. Those skilled in the art will appreciate that Figure 4 It is only an example of terminal 4 and does not constitute a limitation on terminal 4. It may include more or fewer components than shown in the figure, or a combination of certain components, or different components. For example, the terminal may also include input and output devices, network access devices, buses, etc.

[0112] The processor 40 may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor or any conventional processor, etc.

[0113] The memory 41 may be an internal storage unit of the terminal 4, such as a hard disk or memory of the terminal 4. The memory 41 may also be an external storage device of the terminal 4, such as a plug-in hard disk, a smart media card (SMC), a secure digital (SD) card, a flash card, etc. equipped on the terminal 4. Further, the memory 41 may also include both an internal storage unit and an external storage device of the terminal 4. The memory 41 is used to store the computer program and other programs and data required by the terminal. The memory 41 may also be used to temporarily store data that has been output or is to be output.

[0114] The technicians in the relevant field can clearly understand that for the convenience and simplicity of description, only the division of the above-mentioned functional units and modules is used as an example for illustration. In practical applications, the above-mentioned function allocation can be completed by different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiment can be integrated in a processing unit, or each unit can exist physically separately, or two or more units can be integrated in one unit. The above-mentioned integrated unit can be implemented in the form of hardware or in the form of software functional units. In addition, the specific names of the functional units and modules are only for the convenience of distinguishing each other, and are not used to limit the scope of protection of this application. The specific working process of the units and modules in the above-mentioned system can refer to the corresponding process in the aforementioned method embodiment, which will not be repeated here.

[0115] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0116] Those skilled in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present invention.

[0117] In the embodiments provided by the present invention, it should be understood that the disclosed devices / terminals and methods can be implemented in other ways. For example, the device / terminal embodiments described above are only schematic. For example, the division of the modules or units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0118] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0119] In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0120] If the integrated module / unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the present invention implements all or part of the processes in the above-mentioned embodiment method, and can also be completed by instructing the relevant hardware through a computer program. The computer program can be stored in a computer-readable storage medium. When the computer program is executed by a processor, the steps of the above-mentioned calculation method of the fracture toughness of each SMA can be implemented. Among them, the computer program includes computer program code, and the computer program code can be in source code form, object code form, executable file or some intermediate form. The computer-readable medium may include: any entity or device capable of carrying the computer program code, recording medium, U disk, mobile hard disk, disk, optical disk, computer memory, read-only memory (ROM), random access memory (RAM), electric carrier signal, telecommunication signal and software distribution medium.

[0121] The embodiments described above are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included in the protection scope of the present invention.

Claims

1. A method for calculating the fracture toughness of SMAs, characterized in that: include: A crack growth test is performed on the SMAs to be tested at a preset temperature to determine the increment of elastic components and the increment of inelastic components under the load-displacement curve from the previous cycle to the current cycle; Calculating the J integral of the SMAs to be tested in the current cycle according to the elastic component increment and the inelastic component increment; The fracture toughness value of the SMAs to be tested is determined based on the J-integral of the SMAs to be tested.

2. The method for calculating the fracture toughness of SMAs according to claim 1, characterized in that: Determining the elastic component increment and the inelastic component increment under the load-displacement curve from the previous cycle to the current cycle includes: according to Determine the elastic component increment and the inelastic component increment under the load-displacement curve from the previous cycle to the current cycle; in, represents the elastic component increment under the load-displacement curve from the (i-1)th cycle to the i-th cycle in the crack growth test, P i represents the load applied to the SMAs to be tested in the i-th cycle of the crack growth test, P i-1 represents the load applied to the SMAs to be tested in the (i-1)th cycle of the crack growth test, represents the elastic displacement component in the i-th cycle of the crack growth test, represents the elastic displacement component in the (i-1)th cycle of the crack growth test, C i represents the unloading elastic compliance in the crack growth test, represents the inelastic component increment under the load-displacement curve from the (i-1)th cycle to the i-th cycle in the crack growth test, represents the inelastic displacement component in the i-th cycle of the crack growth test, represents the inelastic displacement component in the (i-1)th cycle of the crack growth test, δ i represents the total displacement component in the i-th cycle in the crack growth test.

3. The method for calculating the fracture toughness of SMAs according to claim 2, characterized in that: The calculating the J integral of the SMAs to be tested in the current cycle according to the elastic component increment and the inelastic component increment includes: Calculating the elastic component of the J-integral of the SMAs to be tested according to the elastic component increment; Calculating the inelastic component of the J-integral of the SMAs to be tested according to the inelastic component increment; The J-integral of the SMAs to be measured is calculated based on the elastic component of the J-integral and the inelastic component of the J-integral.

4. The method for calculating the fracture toughness of SMAs according to claim 3, characterized in that: The step of calculating the elastic component of the J-integral of the SMAs to be tested according to the elastic component increment comprises: according to Calculate the elastic component of the J-integral of the SMAs to be tested; in, represents the elastic component of the J-integral of the SMAs to be measured in the ith week, represents the elastic component of the J-integral of the (i-1)th weekly SMAs to be measured, represents the elastic-plastic factor of the (i-1)th period, B represents the thickness of the SMAs to be tested, and b i-1 represents the length of the unruptured ligament on the SMAs to be measured at the (i-1)th week, represents the geometric correlation factor, a i represents the crack depth on the SMAs to be measured in the (i-1)th week, a i-1 represents the crack depth on the SMAs to be measured in the (i-1)th week.

5. The method for calculating the fracture toughness of SMAs according to claim 4, characterized in that: The method of determining Where W represents the width of the SMAs to be measured; The method of determining 6. The method for calculating the fracture toughness of SMAs according to claim 3, characterized in that: The step of calculating the inelastic component of the J-integral of the SMAs to be tested according to the inelastic component increment comprises: according to Calculate the inelastic component of the J-integral of the SMAs to be tested; in, represents the inelastic component of the J-integral of the SMAs to be measured in the ith week, represents the inelastic component of the J-integral of the (i-1)th weekly SMAs to be measured, represents the inelastic plastic factor of the (i-1)th period, represents the geometric correlation factor.

7. The method for calculating the fracture toughness of SMAs according to claim 6, characterized in that: The method of determining The method of determining 8. A device for calculating the fracture toughness of SMAs, characterized in that: include: A calculation module, for performing a crack growth test on the SMAs to be tested at a preset temperature, and determining an elastic component increment and an inelastic component increment under a load-displacement curve from a previous cycle to a current cycle; The calculation module is further used to calculate the J integral of the SMAs to be tested in the current cycle according to the elastic component increment and the inelastic component increment; A processing module is used to determine the fracture toughness value of the SMAs to be tested according to the J-integral of the SMAs to be tested.

9. A terminal comprising a memory and a processor, wherein the memory is used to store a computer program, and the processor is used to call and run the computer program stored in the memory, characterized in that: When the processor executes the computer program, the processor implements the steps of the method for calculating the fracture toughness of SMAs as described in any one of claims 1 to 7 above.

10. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the computer program implements the steps of the method for calculating the fracture toughness of SMAs as described in any one of claims 1 to 7 above.

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