Additive metal fatigue life-cycle rapid prediction method based on damage and fracture

Abstract

The invention relates to the technical field of metal fatigue prediction, in particular to a damage and fracture-based additive metal fatigue full-life rapid prediction method, device and equipment and a computer readable storage medium, and the method comprises the following steps: obtaining three-dimensional geometric parameters of internal hole defects; the porosity of the edge of each dangerous defect is calculated, and the critical load of the hole defect is obtained; introducing an equivalent crack surface at the original position of the defect, and calculating an equivalent initial crack length by utilizing the damage constitutive model; and a semi-analytical crack propagation algorithm is adopted, the propagation processes of the surface cracks, the embedded cracks and the corner cracks in the component are calculated, the crack propagation life is obtained, and the shortest crack propagation life is defined as the final structural fatigue full life. The damage constitutive model is utilized to fully consider the damage evolution and load coupling effect of the defect, and the semi-analytical crack propagation calculation method is combined with the acceleration algorithm and the crack conversion mechanism, so that the calculation efficiency is remarkably improved, and the rapid evaluation requirement in engineering practice is met.

Description

Technical Field

[0001] This application relates to the field of metal fatigue prediction technology, and in particular to a method, device, electronic device and computer-readable storage medium for rapid prediction of the entire life of additive metal fatigue based on damage and fracture. Background Technology

[0002] Additive manufacturing technology, as a disruptive rapid prototyping process, has demonstrated enormous potential in the fields of materials science and engineering. Compared to traditional metal forming methods, it offers significant advantages in design-manufacturing integration, achieving near-net-shape forming, and handling complex configurations, thus gradually becoming a preferred path to solve many technical bottlenecks and challenges in the high-end equipment manufacturing field. This technology can flexibly construct components with highly complex geometries, greatly expanding the freedom of product design and significantly shortening the cycle from design to prototype and even final product. Therefore, it has broad application prospects and is receiving increasing attention in industrial fields such as aerospace, biomedicine, automotive, and energy, where structural performance and reliability requirements are extremely stringent.

[0003] However, the inherent characteristics of additive manufacturing processes, such as layer-by-layer deposition, rapid cooling and solidification, and complex thermal histories, often inevitably result in internal defects in the final metal components. These defects, most notably porosity, unfused regions, or inclusions, exhibit complex and varied geometries and highly random spatial distribution and orientation, directly and significantly impacting the macroscopic mechanical properties of the material, particularly its fatigue performance. Under cyclic loading, fatigue failure often initiates at these defects, leading to stress concentration and ultimately structural failure. Therefore, accurately assessing and predicting the full lifespan of additively manufactured components under fatigue loading has become a critical issue that urgently needs to be addressed to ensure the service safety and reliability of additively manufactured components. Summary of the Invention

[0004] This application aims to at least partially address one of the technical problems in the related art.

[0005] Therefore, the first objective of this application is to propose a rapid prediction method for the full life of additive metal fatigue based on damage and fracture, so as to solve the problem that existing technologies cannot accurately assess and predict the full life of metal components under fatigue loads.

[0006] The second objective of this application is to provide an apparatus.

[0007] The third objective of this application is to propose an electronic device.

[0008] The fourth objective of this application is to provide a computer-readable storage medium.

[0009] To achieve the above objectives, the first aspect of this application proposes a rapid prediction method for the entire fatigue life of additive metals based on damage and fracture, comprising: Non-destructive testing is performed on additively manufactured metal components to obtain the three-dimensional geometric parameters of internal pore defects; Based on the aforementioned three-dimensional geometric parameters, multiple defects with the largest defect sizes are selected as hazardous defects. The porosity of each dangerous defect edge is calculated using a damage constitutive model to obtain the critical load of the pore defect; An equivalent crack surface is introduced at the original location of the defect. Based on the critical load of the hole defect, the equivalent initial crack length is calculated using the damage constitutive model. Based on the equivalent initial crack length, a semi-analytical crack propagation algorithm is used to calculate the propagation process of surface cracks, embedded cracks, and corner cracks in the component, obtain the crack propagation life, and define the shortest crack propagation life as the final structural fatigue life.

[0010] Preferably, the non-destructive testing of the additively manufactured metal component to obtain the three-dimensional geometric parameters of internal void defects includes: Three-dimensional non-destructive testing of additively manufactured metal components is performed using an industrial computer tomography system to obtain three-dimensional geometric morphology information of internal defects in the additively manufactured metal components. Based on the aforementioned three-dimensional geometric morphology information, a cone-beam CT three-dimensional reconstruction algorithm is used to reconstruct the image, and the reconstructed image is processed to generate the three-dimensional geometric parameters of the internal hole defects.

[0011] Preferably, the image processing includes: grayscale thresholding, connected component analysis, and morphological operations.

[0012] Preferably, the step of selecting multiple defects with the largest defect size as hazardous defects based on the three-dimensional geometric parameters includes: Based on the dimensions of the three-dimensional geometric parameters, the defects are sorted from largest to smallest, and the largest defects are selected as the dangerous defects for fatigue life calculation.

[0013] Preferably, the step of calculating the porosity of each critical defect edge using a damage constitutive model to obtain the critical load of the pore defect includes: Construct a three-dimensional finite model containing an ellipsoidal hole, with the outside of the hole being a nearly infinite or finite solid. A tensile load consistent with the actual load direction is applied to the three-dimensional finite model; The porosity at each point on the edge of the hole is calculated in real time using a damage constitutive model. Gradually increase the load until the porosity at a certain point on the edge of the hole reaches the material's preset critical porosity for the first time. The applied load at this point is the critical load of the hole defect.

[0014] Preferably, the step of introducing an equivalent crack surface at the original location of the defect, and calculating the equivalent initial crack length using the damage constitutive model based on the critical load of the void defect, includes: Reconstruct the three-dimensional finite model, remove the ellipsoidal hole space, and place a cracked surface in its original position; A tensile load in the same direction as the actual mechanical load is applied to the reconstructed three-dimensional finite model. The porosity at the crack tip is calculated using the damage constitutive model. The crack length is adjusted. When the porosity at the crack tip reaches the critical porosity, the corresponding crack length is the equivalent initial crack length of the defect.

[0015] Preferably, the step of using a semi-analytical crack propagation algorithm based on the equivalent initial crack length to calculate the propagation process of surface cracks, embedded cracks, and corner cracks in the component, obtaining the crack propagation life, and defining the shortest crack propagation life as the final structural fatigue life includes: Based on the equivalent initial crack length, a semi-analytical crack propagation algorithm is used to calculate the propagation rate and direction of surface cracks, embedded cracks, and corner cracks. The stress intensity factor is quickly obtained using analytical formulas. Based on the stress intensity factor, the crack propagation amount is calculated using the crack propagation rate equation. A crack mode transformation rule is introduced. When the crack tip touches the free surface or component boundary, the crack type is immediately changed according to the preset rule, and the lifetime consumed by the crack transformation itself is ignored. When a crack penetrates the entire cross-section, failure is determined. The cumulative number of cycles is the crack propagation life corresponding to this dangerous defect, which is the final structural fatigue life.

[0016] To achieve the above objectives, a second aspect of this application provides a rapid prediction device for the entire fatigue life of additive metals based on damage and fracture, comprising: The data acquisition module performs non-destructive testing on additively manufactured metal components to obtain the three-dimensional geometric parameters of internal holes and defects; The hazardous defect selection module filters out multiple defects with the largest defect size as hazardous defects based on the three-dimensional geometric parameters. The critical load calculation module uses a damage constitutive model to calculate the porosity of each dangerous defect edge and obtain the critical load of the pore defect. The equivalent crack calculation module introduces an equivalent crack surface at the original location of the defect, and calculates the equivalent initial crack length based on the critical load of the hole defect using the damage constitutive model. The fatigue life acquisition module, based on the equivalent initial crack length, uses a semi-analytical crack propagation algorithm to calculate the propagation process of surface cracks, embedded cracks, and corner cracks in the component, obtains the crack propagation life, and defines the shortest crack propagation life as the final structural fatigue life.

[0017] To achieve the above objectives, a third aspect of this application provides an electronic device, including: a processor, and a memory communicatively connected to the processor; The memory stores computer-executed instructions; The processor executes computer execution instructions stored in the memory to implement the method described in any of the preceding descriptions.

[0018] To achieve the above objectives, a fourth aspect of this application provides a computer-readable storage medium, comprising computer-executable instructions stored therein, which, when executed by a processor, are used to implement the method described in any of the above embodiments.

[0019] This application presents a rapid fatigue life prediction method for additive metals based on damage and fracture, aiming to overcome the limitations of existing technologies in additive metal fatigue life prediction. By utilizing a damage constitutive model, the damage evolution of defects and the coupling effect of loads are fully considered, thereby determining a more physically meaningful equivalent initial crack length. A semi-analytical crack propagation calculation method, combined with an accelerated algorithm and crack transformation mechanism, significantly improves computational efficiency, enabling it to meet the rapid assessment needs in practical engineering. This method provides more reliable and conservative fatigue life prediction results by comprehensively analyzing multiple potential hazardous defects and using the shortest life as the total life of the component. This has important guiding significance for the design, certification, and service safety of additively manufactured metal components.

[0020] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0021] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein: Figure 1 The flowchart is a first specific embodiment of the additive metal fatigue life rapid prediction method based on damage and fracture provided by the present invention. Figure 2 The flowchart is a second specific embodiment of the additive metal fatigue life rapid prediction method based on damage and fracture provided by the present invention. Figure 3The GTN model parameter diagram for IN718 alloy; Figure 4 The actual stress-strain curves and schematic diagrams of the stress-strain curves of the material under the Ramberg-Osgood model are shown. Figure 5 This is a schematic diagram of a semi-elliptical crack on the surface. Figure 6 This is a schematic diagram of an embedded elliptical crack. Figure 7 This is a schematic diagram of a corner crack; Figure 8 This is a schematic diagram of crack transformation, where the dashed lines represent the original cracks and the solid lines represent the new cracks; Figure 9 This is a structural block diagram of an additive metal fatigue life rapid prediction device based on damage and fracture, provided in an embodiment of the present invention. Detailed Implementation

[0022] The core of this invention is to provide a method, device, electronic device, and computer-readable storage medium for rapid prediction of the fatigue life of additive metals based on damage and fracture. By integrating the principles of damage mechanics and fracture mechanics, it accurately models and analyzes the complex defects inside additively manufactured metal components, thereby achieving accurate and rapid prediction of the fatigue life of the components.

[0023] To enable those skilled in the art to better understand the present invention, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. Obviously, the described embodiments are merely some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] Please refer to Figure 1 , Figure 1 The flowchart illustrates a first specific embodiment of a rapid prediction method for the entire fatigue life of additive metals based on damage and fracture provided by this invention; the specific operation steps are as follows: Step S101: Perform non-destructive testing on the additively manufactured metal component to obtain the three-dimensional geometric parameters of internal hole defects; Step S102: Select the multiple defects with the largest defect size as dangerous defects based on the three-dimensional geometric parameters; Step S103: Calculate the porosity of each critical defect edge using the damage constitutive model to obtain the critical load of the pore defect; Step S104: Introduce an equivalent crack surface at the original location of the defect, and calculate the equivalent initial crack length using the damage constitutive model based on the critical load of the pore defect. Step S105: Based on the equivalent initial crack length, a semi-analytical crack propagation algorithm is used to calculate the propagation process of surface cracks, embedded cracks and corner cracks in the component, obtain the crack propagation life, and define the shortest crack propagation life as the final structural fatigue life.

[0025] Based on the above embodiments, this embodiment will provide a detailed description of step S101: In one embodiment, an industrial computer tomography system is used to perform three-dimensional non-destructive testing on additively manufactured metal components to obtain three-dimensional geometric morphology information of internal defects in the additively manufactured metal components. Based on three-dimensional geometric topography information, a cone-beam CT three-dimensional reconstruction algorithm is used to reconstruct the image, and the reconstructed image is processed to generate three-dimensional geometric parameters of internal hole defects. The image processing includes grayscale thresholding, connected component analysis and morphological operations.

[0026] Specifically, an industrial computed tomography (CT) system is used to perform three-dimensional non-destructive testing on the additively manufactured metal component to obtain three-dimensional geometric morphology information of internal defects in the component. The industrial CT scanning system is equipped with an X-ray tube and a flat panel detector. The original projection data obtained by CT scan is used to reconstruct the image using a cone-beam CT three-dimensional reconstruction algorithm to generate three-dimensional voxel data of the component. Image processing is performed on three-dimensional voxel data, including grayscale thresholding, connected component analysis, and morphological operations, to accurately identify and separate defects such as pores, unfused areas, or inclusions inside the component. For each identified defect, its specific geometric parameters are extracted. These parameters include the lengths of the major, middle, and minor axes of the equivalent ellipsoid, the spatial direction vector of the ellipsoid, the centroid coordinates, the volume, the surface area, and the shape factor. Based on a preset defect size threshold or combined with preliminary local stress concentration analysis, several potentially dangerous defects that have a significant impact on the fatigue life of the component are selected from all identified defects as the focus of subsequent precise analysis. For selected defects with complex shapes, their geometry is simplified to an approximate ellipsoid or a shape composed of multiple simple geometric shapes.

[0027] Based on the above embodiments, this embodiment will provide a detailed description of step S102: In one embodiment, based on the dimensions of the three-dimensional geometric parameters, the defects are sorted from largest to smallest, and the largest defects are selected as the dangerous defects for fatigue life calculation.

[0028] Based on the above embodiments, this embodiment will provide a detailed description of step S103: In one embodiment, a three-dimensional finite model containing an ellipsoidal hole is constructed, with the area outside the hole being a near-infinite or finite-sized solid. A tensile load consistent with the actual load direction is applied to the three-dimensional finite model; The porosity at each point on the edge of the hole is calculated in real time using a damage constitutive model. Gradually increase the load until the porosity at a certain point on the edge of the hole reaches the material's preset critical porosity for the first time. The applied load at this point is the critical load of the hole defect.

[0029] Specifically, a local three-dimensional finite element model is constructed, which includes a solid region with embedded defect geometry, wherein the boundary size of the solid region is 10 to 20 times the size of the defect feature. In the finite element model, the damage constitutive model (GTN) is integrated through a user subroutine or the built-in material model interface; The finite element model is meshed, and a fine meshing strategy is used in the defect edge and its vicinity to ensure that the local mesh size is less than 1 / 10 of the defect feature size. The mesh element type is an eight-node hexahedral reduced integral element (C3D8R), and a coarse mesh is used in the far field region. Apply cyclic tensile loads that match the actual service conditions of the component. The loads can be uniaxial tensile or complex multiaxial tensile loads. The load direction fully considers the relative orientation relationship with the long axis of the defect. The boundary conditions of the model are set to avoid rigid body displacement and simulate far-field infinite body effects. Numerical iterative calculations are performed, with the external load gradually increased in incremental steps. In each load increment step, the evolution of stress, strain, and porosity at each point on the defect edge is calculated using the GTN model. The critical porosity criterion is used to determine the macroscopic failure of the defect. The porosity evolution at the defect edge is continuously monitored. When the porosity at any point on the defect edge reaches the critical porosity, the external load value at this time is recorded and defined as the critical load for macroscopic failure of the defect.

[0030] Based on the above embodiments, this embodiment will provide a detailed description of step S104: In one embodiment, a three-dimensional finite model is reconstructed, the ellipsoidal hole space is removed, and a crack surface is placed in its original position. A tensile load in the same direction as the actual mechanical load is applied to the reconstructed three-dimensional finite model. The porosity at the crack tip is calculated using a damage constitutive model, and the crack length is adjusted. When the porosity at the crack tip reaches the critical porosity, the corresponding crack length is the equivalent initial crack length of the defect.

[0031] Specifically, a three-dimensional finite element model is reconstructed, the ellipsoidal cavity space is removed, and a crack surface is placed in its original position. The shape of the crack surface is determined based on the position of the ellipsoidal cavity in the structure; for example, the crack surface is elliptical for internal defects and semi-elliptical for surface defects. The normal of the crack surface should be perpendicular to the major axis of the ellipsoidal cavity, and the major axis of the crack surface should be in the same direction as the major axis of the ellipsoidal cavity. A tensile load with the same direction as the actual mechanical load is applied, and the load magnitude is the critical load. The porosity at the crack tip is calculated using the GTN model, and the crack length is adjusted. When the porosity at the crack tip reaches the critical porosity, the crack length is determined as the equivalent crack length.

[0032] Based on the above embodiments, this embodiment will provide a detailed description of step S104: In one embodiment, based on the equivalent initial crack length, a semi-analytical crack propagation algorithm is used to calculate the propagation rate and propagation direction of surface cracks, embedded cracks, and corner cracks, wherein the stress intensity factor is quickly obtained using analytical formulas. The crack propagation amount is calculated based on the stress intensity factor and the crack propagation rate equation. A crack mode transformation rule is introduced. When the crack tip touches the free surface or component boundary, the crack type is immediately changed according to the preset rule, and the lifetime consumed by the crack transformation itself is ignored. When a crack penetrates the entire cross-section, failure is determined. The cumulative number of cycles is the crack propagation life corresponding to this dangerous defect, which is the final structural fatigue life.

[0033] Specifically, an equivalent crack is set as the initial crack, and rapid crack propagation calculations are performed. Surface cracks still propagate in a semi-elliptical shape, embedded cracks propagate in an elliptical shape, and corner cracks propagate in a quarter-elliptical shape, allowing variations in the aspect ratio of the cracks. For surface semi-elliptical cracks, the crack shape variation is calculated by separately calculating the crack frontal propagation at the surface point and the deepest point. The crack stress intensity factor formula is retrieved, and crack propagation calculations are performed primarily in two directions: parallel to the surface of the thin-walled structure and parallel to the thickness of the thin-walled structure. The crack propagation rate is determined by the Paris equation. To accelerate the calculation, the maximum crack propagation of equal length is used as an interval, assuming the crack is in the m-th interval, starting from the length... Extended to During the process, if the stress intensity factor remains constant, then the crack propagation life in the m-th interval satisfies the equation When the crack tip encounters the specimen boundary during crack propagation, a crack transformation occurs. To accelerate the simulation of crack propagation, the crack transformation mechanism needs to be simplified. In this method, it is assumed that the crack immediately transforms into a new crack upon reaching the specimen boundary, and the crack propagation life consumed during the crack transformation process is ignored.

[0034] For the 10 largest defects, rapid crack propagation calculations were performed. The crack propagation life obtained based on the aforementioned method is the total fatigue life when the defect is the main hazard point. The total fatigue life caused by each defect as the main hazard point was compared, and the shortest life among them was determined as the final total structural fatigue life.

[0035] This embodiment provides a rapid fatigue life prediction method for additive metals based on damage and fracture, aiming to overcome the limitations of existing technologies in additive metal fatigue life prediction. By utilizing a damage constitutive model, the damage evolution of defects and the coupling effect of loads are fully considered, thereby determining a more physically meaningful equivalent initial crack length. A semi-analytical crack propagation calculation method, combined with an accelerated algorithm and crack transformation mechanism, significantly improves computational efficiency, enabling it to meet the rapid assessment needs in practical engineering. This method provides more reliable and conservative fatigue life prediction results by comprehensively analyzing multiple potential hazardous defects and using the shortest life as the total life of the component. This has important guiding significance for the design, certification, and service safety of additively manufactured metal components.

[0036] Based on the above embodiments, this embodiment describes the model structure of the method for rapid prediction of the entire fatigue life of additive metals based on damage and fracture, as follows: Figure 2 As shown, the details are as follows: First, industrial CT scanning technology is used to characterize the voids and defects in the additive structure, obtaining information such as the size, shape, and orientation of the defects. Then, the larger defects are focused on, as these are usually more dangerous. For example, the 10 largest defects can be selected as the main objects of analysis.

[0037] Finite element method (FEM) simulations were conducted to determine the critical loads for the 10 largest hole defects. This involved constructing an ellipsoidal hole space and surrounding it with a near-infinite three-dimensional solid much larger than the hole, or creating a finite-sized three-dimensional solid based on the hole defect's location within the structure (e.g., near the surface). A mesh was generated, and a tensile load in the same direction as the actual mechanical load was applied. The porosity at the edge of the ellipsoidal hole was calculated using the GTN model. The tensile load was adjusted, and the load at which the porosity at any point on the edge of the ellipsoidal hole reached the critical porosity was recorded as the critical load. At this point, the hole's load-bearing capacity decreased, and failure began.

[0038] Finite element simulation was conducted to determine the equivalent crack lengths of the 10 largest pore defects. This included: constructing a 3D finite element model, removing the space of the ellipsoidal pores, and placing a crack surface in their original positions. The shape of the crack surface was determined based on the position of the ellipsoidal pore in the structure; for example, the crack surface was elliptical for internal defects and semi-elliptical for surface defects. The normal to the crack surface should be perpendicular to the major axis of the ellipsoidal pore, and the major axis of the crack surface should be in the same direction as the major axis of the ellipsoidal pore. A tensile load with the same direction as the actual mechanical load was applied, and the magnitude of the load was the critical load. The porosity at the crack tip was calculated using the GTN model, and the crack length was adjusted. When the porosity at the crack tip reached the critical porosity, that crack length was determined as the equivalent crack length.

[0039] An equivalent crack is set as the initial crack, and rapid crack propagation calculations are performed. Surface cracks still propagate in a semi-elliptical shape, embedded cracks propagate in an elliptical shape, and corner cracks propagate in a quarter-elliptical shape, allowing variations in the aspect ratio of the cracks. For surface semi-elliptical cracks, the crack shape variation is calculated by separately calculating the crack frontal propagation at the surface point and the deepest point. The crack stress intensity factor formula is retrieved, and crack propagation calculations are performed primarily in two directions: parallel to the surface of the thin-walled structure and parallel to the thickness of the thin-walled structure. The crack propagation rate is determined by the Paris equation. To accelerate the calculation, the maximum crack propagation of equal length is used as an interval, assuming the crack is in the m-th interval, starting from the length... Extended to During the process, the stress intensity factor remains constant, and the crack propagation life in the m-th interval satisfies the equation. When the crack tip encounters the specimen boundary during propagation, a crack transformation occurs. To accelerate the simulation of crack propagation, the crack transformation method needs to be simplified. In this method, it is assumed that the crack immediately transforms into a new crack when it propagates to the specimen boundary, and the crack propagation life consumed by the crack transformation process is ignored.

[0040] For the 10 largest defects, rapid crack propagation calculations were performed. The crack propagation life obtained based on the aforementioned method is the total fatigue life when the defect is the main hazard point. The total fatigue life caused by each defect as the main hazard point was compared, and the shortest life among them was determined as the final total structural fatigue life.

[0041] Based on the above embodiments, this embodiment describes the damage constitutive model (GTN) as follows: The GTN damage model incorporates the initiation, growth, and combined effects of porosity defects into the yield function, and the modified yield function F is written as follows:

[0042] In the formula, It is macroscopic von Mises stress. It is the yield stress of the matrix material. It is hydrostatic pressure. For model parameters, The effective porosity describes the significant decrease in the load-bearing capacity of the matrix material caused by the interconnectedness of pores, and is expressed as:

[0043] in , It is the porosity when the pores begin to bond together, which is macroscopically manifested as the stress-strain curve starting to decrease. This refers to the porosity at the point of final failure. The increase in total porosity can be divided into initial growth and subsequent decline. and extension Two parts, namely:

[0044] The extended portion is related to the accumulation of plastic deformation and assumes that the matrix material is plastically incompressible, expressed as follows:

[0045] It is the volumetric component of the plastic strain rate tensor. Pore initiation is also controlled by plastic strain, and its initiation process follows a normal distribution, expressed as...

[0046] in, It is the volume fraction of two-phase particles that can initiate pore formation. and These represent the average strain and its standard deviation at the initiation of pores. For equivalent plastic strain, the following formula can be used to calculate it based on the equivalent plastic work:

[0047] The above equation contains a total of 7 model parameters: Some of these parameters have empirical values, for example... The remaining five parameters can be obtained by fitting the material's monotonic tensile curve. For example, in the commercial software ABAQUS, the monotonic tensile process can be simulated, and the parameter values ​​can be adjusted using optimization algorithms to fit the engineering stress-strain curve obtained from the experiment. For example, for the IN718 alloy, the model parameters at room temperature are as follows: Figure 3 As shown in the figure These are fitting parameters or empirical parameters, and are all constants. If there are sufficient experimental results, they can be obtained by fitting the experimental results; if there are few experimental data, empirical values ​​can be used as a reference. It is the porosity when the pores begin to coalesce. It is the porosity at the point of final failure. It is the volume fraction of two-phase particles that can initiate pore formation. and These represent the average strain and its standard deviation during pore initiation, respectively.

[0048] If the stress-strain curves obtained from the experiment are unsatisfactory, the stress-strain relationship of the material can be given first using the Ramberg-Osgood model:

[0049] in These are Young's modulus and plasticity-related parameters of the material. These are strain and stress, respectively. Stress-strain curves under different parameters are shown below. Figure 4 Then, the GTN model parameters are determined through fitting.

[0050] Based on the above embodiments, this embodiment describes the method for calculating the equivalent initial crack length of pore defects, as follows: To calculate the equivalent crack length, the critical load at which the void defect causes failure needs to be determined first. This requires characterizing the void defect in the additive structure using industrial CT scanning technology to obtain its size, shape, orientation, etc. Then, we focus on the larger defects, which are typically more dangerous. Generally, additive manufacturing void defects are ellipsoidal in shape; for ease of calculation, we use an ellipsoid as a typical object in our finite element simulation, as detailed below.

[0051] Construct an ellipsoidal void space and set up a nearly infinite three-dimensional solid with a size much larger than the void on the outside, or set up a finite three-dimensional solid according to the distribution location of the void defect in the structure (such as near the surface).

[0052] The process involves meshing the holes and applying a tensile load in the same direction as the actual mechanical load, taking into account both the load direction and the orientation of the major axis of the ellipsoidal hole. The porosity at the edge of the ellipsoidal hole is calculated using the GTN model. The magnitude of the tensile load is adjusted, and the load at which the porosity at any point on the edge of the ellipsoidal hole reaches the critical porosity is recorded as the critical load. At this point, the load-bearing capacity of the hole edge decreases, and failure begins.

[0053] Reconstruct the 3D finite element model, remove the ellipsoidal hole space, and place a crack surface in its original position. The shape of the crack surface is determined by the position of the ellipsoidal hole in the structure; for example, the crack surface is elliptical for internal defects and semi-elliptical for surface defects. The normal of the crack surface should be perpendicular to the major axis of the ellipsoidal hole, and the major axis of the crack surface should be in the same direction as the major axis of the ellipsoidal hole.

[0054] A tensile load in the same direction as the actual mechanical load is applied, and the load magnitude is the critical load. The porosity at the crack tip is calculated using the GTN model. The crack length is adjusted, and when the porosity at the crack tip reaches the critical porosity, the crack length is determined as the equivalent crack length.

[0055] Based on the above embodiments, this embodiment describes a rapid crack propagation calculation method as follows: In engineering design, fatigue crack propagation life analysis is one of the important means to determine the safety of components. Crack propagation life is commonly calculated in two ways: numerical calculation and semi-analytical methods. Numerical calculation methods require building a model, dividing it into elements, and calculating the stress intensity factor distribution at the crack tip and the crack propagation rate week by week. This process requires mesh generation week by week and the use of finite element software, consuming significant computational resources and time, and cannot provide rapid crack propagation life estimation.

[0056] To perform rapid crack propagation life analysis, a semi-analytical method can be used. This process simplifies the specimen to simple shapes, such as plates, cylinders, and tubes. Cracks can also be simplified to surface semi-elliptical cracks, internal elliptical cracks, corner cracks, and edge cracks. After simplification, the stress intensity factor distribution at the crack tip can be calculated using empirical formulas, thus allowing for rapid calculation of the crack propagation process. When analyzing the propagation of a single surface crack, the crack is typically simplified to a surface semi-elliptical crack. Different methods, such as single-degree-of-freedom, two-degree-of-freedom, and multi-degree-of-freedom methods, can be used for crack propagation analysis using analytical methods and the finite element method. The two-degree-of-freedom method is widely used due to its combination of accuracy and speed.

[0057] In the two-degree-of-freedom assumption, surface cracks still propagate in a semi-elliptical shape, embedded cracks propagate in an elliptical shape, and corner cracks propagate in a quarter-elliptical shape, allowing for variations in the aspect ratio of the cracks. For surface semi-elliptical cracks, the crack shape variation is calculated by separately calculating the crack leading-edge propagation at the surface point and the deepest point.

[0058] Based on their location within the flat plate, planar cracks can be classified into three types: corner cracks, edge cracks, and embedded cracks. The shape of the naturally occurring initial crack lead is quite complex and cannot be used in two-degree-of-freedom fatigue crack propagation calculations. Even using the finite element method, the initial crack shape cannot be completely guaranteed after mesh generation. Therefore, the shape of the planar crack needs to be simplified in the calculation.

[0059] The stress intensity factor for an elliptical crack within a flat plate exists according to a formula, which facilitates the calculation of crack propagation in both directions. For example... Figure 5 , Figure 6 , Figure 7As shown, the simplified dimension of the crack parallel to the length of the plate (i.e., parallel to the surface of the thin-walled structure) is: or The dimension perpendicular to the length direction of the plate (i.e., the thickness direction of the thin-walled structure) is or The length of the plate is defined as Thickness is defined as The distance from the center of the crack surface to the surface of the flat plate is... The picture Let be the angle between the crack tip and the length direction of the plate. Points A and C represent the two vertices of the elliptical crack tip. When the simplified crack contains a complete elliptical shape in a certain direction, the dimension needs to be multiplied by 2.

[0060] Within the framework of linear elastic fracture mechanics, the crack propagation rate can be expressed by the Paris equation:

[0061] In the formula The number of cycles is The amount of crack propagation around the clock. For the range of stress intensity factors, These are the fitting parameters. It's important to note that the stress intensity factor range is a function of the crack length, i.e. .

[0062] Although calculating the stress intensity factor and crack propagation using empirical formulas is much more efficient than using finite element methods, the computation time is still considerable when the crack propagation life is long enough. Therefore, an accelerated algorithm is needed, specifically by fixing the crack length variation. Calculate interval lifetime Using the maximum crack propagation of equal length as an interval, assuming the crack is in the m-th interval, from length... Extended to If the stress intensity factor remains constant during the process, then the crack propagation life in the m-th interval satisfies the following equation:

[0063] Since we simplified the crack surface to an ellipse, semi-ellipse, or quarter-ellipse, we need to consider both the major and minor axes of the elliptical crack when calculating crack propagation. After determining the crack propagation in these two main directions, we obtain a new crack surface based on the new major and minor axis lengths.

[0064] In a three-dimensional structure, when the crack tip encounters the specimen boundary during crack propagation, a crack transformation occurs. To simulate the crack propagation process, the crack transformation mechanism needs to be simplified. Crack transformation can take several forms, such as... Figure 8 As shown: an embedded crack transforms into a surface crack (EC-SC); a surface crack transforms into a corner crack (SC-CC); a surface crack transforms into a through crack (SC-TC); and a corner crack transforms into a side crack (CC-BC). The dashed lines in the figure represent the crack leading edge before transformation, and the corresponding crack size is determined by... and The converted crack size is represented by... and To express.

[0065] In this method, it is assumed that a crack immediately transforms into a new crack upon reaching the specimen boundary, and the crack propagation life consumed during the crack transformation process is ignored. Failure occurs when the crack propagates throughout the entire structure. Therefore, the crack propagation life can be quickly calculated based on an equivalent initial crack, ultimately yielding the total fatigue life.

[0066] Please refer to Figure 9 , Figure 9 This invention provides a structural block diagram of a rapid prediction device for the entire fatigue life of additive metals based on damage and fracture; the specific device may include: The data acquisition module 100 performs non-destructive testing on additively manufactured metal components to obtain the three-dimensional geometric parameters of internal holes and defects. The hazardous defect selection module 200 filters multiple defects with the largest defect size as hazardous defects based on the three-dimensional geometric parameters. The critical load calculation module 300 uses a damage constitutive model to calculate the porosity of each dangerous defect edge and obtain the critical load of the pore defect. The equivalent crack calculation module 400 introduces an equivalent crack surface at the original location of the defect, and calculates the equivalent initial crack length based on the critical load of the hole defect using the damage constitutive model. The fatigue life acquisition module 500, based on the equivalent initial crack length, uses a semi-analytical crack propagation algorithm to calculate the propagation process of surface cracks, embedded cracks, and corner cracks in the component, obtains the crack propagation life, and defines the shortest crack propagation life as the final structural fatigue life.

[0067] This embodiment provides a rapid prediction device for the entire fatigue life of additive metals based on damage and fracture, used to implement the aforementioned rapid prediction method for the entire fatigue life of additive metals based on damage and fracture. Therefore, the specific implementation of this device can be found in the embodiment section of the aforementioned rapid prediction method for the entire fatigue life of additive metals based on damage and fracture. For example, the data acquisition module 100, the hazardous defect selection module 200, the critical load calculation module 300, the equivalent crack calculation module 400, and the fatigue life acquisition module 500 are respectively used to implement steps S101, S102, S103, S104, and S105 in the aforementioned rapid prediction method for the entire fatigue life of additive metals based on damage and fracture. Therefore, the specific implementation can be referred to the descriptions of the corresponding embodiments, and will not be repeated here.

[0068] To implement the above embodiments, this application also proposes an electronic device, including: a processor and a memory communicatively connected to the processor; the memory stores computer execution instructions; the processor executes the computer execution instructions stored in the memory to implement the method provided in the foregoing embodiments.

[0069] To implement the above embodiments, this application also proposes a computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, are used to implement the methods provided in the foregoing embodiments.

[0070] To implement the above embodiments, this application also proposes a computer program product, including a computer program that, when executed by a processor, implements the methods provided in the foregoing embodiments.

[0071] The collection, storage, use, processing, transmission, provision, and disclosure of user personal information involved in this application all comply with the provisions of relevant laws and regulations and do not violate public order and good morals.

[0072] It should be noted that personal information collected from users should be used for legitimate and reasonable purposes and should not be shared or sold outside of these legitimate uses. Furthermore, such collection / sharing should only be conducted after receiving the user's informed consent, including but not limited to notifying the user to read the user agreement / user notice and sign an agreement including the relevant user information before the user uses the function. In addition, any necessary steps must be taken to protect and safeguard access to such personal information data and ensure that others with access to personal information data comply with their policies and procedures.

[0073] This application is intended to provide an implementation scheme for users to selectively prevent the use or access to their personal information data. Specifically, this disclosure is intended to provide hardware and / or software to prevent or block access to such personal information data. Risk can be minimized by restricting data collection and deleting data once the personal information data is no longer needed. Furthermore, where applicable, such personal information can be de-identified.

[0074] In the foregoing descriptions of the embodiments, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0075] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0076] Any process or method description in the flowchart or otherwise herein can be understood as representing a module, segment, or portion of code comprising one or more executable instructions for implementing custom logic functions or processes, and the scope of the preferred embodiments of this application includes additional implementations in which functions may be performed not in the order shown or discussed, including substantially simultaneously or in reverse order depending on the functions involved, as should be understood by those skilled in the art to which embodiments of this application pertain.

[0077] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (such as a computer-based system, a processor-included system, or other system that can fetch and execute instructions from, an instruction execution system, apparatus, or device). For the purposes of this specification, "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transmit programs for use by, or in conjunction with, an instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of computer-readable media include: an electrical connection having one or more wires (electronic device), a portable computer disk drive (magnetic device), random access memory (RAM), read-only memory (ROM), erasable and editable read-only memory (EPROM or flash memory), fiber optic devices, and portable optical disc read-only memory (CDROM). Alternatively, the computer-readable medium may be paper or other suitable media on which the program can be printed, since the program can be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, interpreting, or otherwise processing as necessary, and then stored in a computer memory.

[0078] It should be understood that various parts of this application can be implemented using hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented using software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware as in another embodiment, it can be implemented using any one or a combination of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0079] Those skilled in the art will understand that all or part of the steps of the methods in the above embodiments can be implemented by a program instructing related hardware. The program can be stored in a computer-readable storage medium, and when executed, the program includes one or a combination of the steps of the method embodiments.

[0080] Furthermore, the functional units in the various embodiments of this application can be integrated into a processing module, or each unit can exist physically separately, or two or more units can be integrated into a module. The integrated module can be implemented in hardware or as a software functional module. If the integrated module is implemented as a software functional module and sold or used as an independent product, it can also be stored in a computer-readable storage medium.

[0081] The storage medium mentioned above can be a read-only memory, a disk, or an optical disk, etc. Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of this application.

Claims

1. A rapid prediction method for the entire fatigue life of additive metals based on damage and fracture, characterized in that, include: Non-destructive testing is performed on additively manufactured metal components to obtain the three-dimensional geometric parameters of internal pore defects; Based on the aforementioned three-dimensional geometric parameters, multiple defects with the largest defect sizes are selected as hazardous defects. The porosity of each dangerous defect edge is calculated using a damage constitutive model to obtain the critical load of the pore defect; An equivalent crack surface is introduced at the original location of the defect. Based on the critical load of the hole defect, the equivalent initial crack length is calculated using the damage constitutive model. Based on the equivalent initial crack length, a semi-analytical crack propagation algorithm is used to calculate the propagation process of surface cracks, embedded cracks, and corner cracks in the component, obtain the crack propagation life, and define the shortest crack propagation life as the final structural fatigue life.

2. The method for rapid prediction of the entire fatigue life of additive metals based on damage and fracture according to claim 1, characterized in that, The non-destructive testing of the additively manufactured metal component to obtain the three-dimensional geometric parameters of internal voids and defects includes: Three-dimensional non-destructive testing of additively manufactured metal components is performed using an industrial computer tomography system to obtain three-dimensional geometric morphology information of internal defects in the additively manufactured metal components. Based on the aforementioned three-dimensional geometric morphology information, a cone-beam CT three-dimensional reconstruction algorithm is used to reconstruct the image, and the reconstructed image is processed to generate the three-dimensional geometric parameters of the internal hole defects.

3. The method for rapid prediction of the entire fatigue life of additive metals based on damage and fracture according to claim 2, characterized in that, The image processing includes: grayscale thresholding, connected component analysis, and morphological operations.

4. The method for rapid prediction of the entire fatigue life of additive metals based on damage and fracture according to claim 1, characterized in that, The step of selecting the largest defects as hazardous defects based on the three-dimensional geometric parameters includes: Based on the dimensions of the three-dimensional geometric parameters, the defects are sorted from largest to smallest, and the largest defects are selected as the dangerous defects for fatigue life calculation.

5. The method for rapid prediction of the entire fatigue life of additive metals based on damage and fracture according to claim 1, characterized in that, The calculation of the porosity at the edge of each dangerous defect using a damage constitutive model, and the acquisition of the critical load for the pore defect, includes: Construct a three-dimensional finite model containing an ellipsoidal hole, with the outside of the hole being a nearly infinite or finite solid. A tensile load consistent with the actual load direction is applied to the three-dimensional finite model; The porosity at each point on the edge of the hole is calculated in real time using a damage constitutive model. Gradually increase the load until the porosity at a certain point on the edge of the hole reaches the material's preset critical porosity for the first time. The applied load at this point is the critical load of the hole defect.

6. The method for rapid prediction of the entire fatigue life of additive metals based on damage and fracture according to claim 1, characterized in that, The equivalent crack surface introduced at the original location of the defect, and the equivalent initial crack length calculated using the damage constitutive model based on the critical load of the void defect, includes: Reconstruct the three-dimensional finite model, remove the ellipsoidal hole space, and place a cracked surface in its original position; A tensile load in the same direction as the actual mechanical load is applied to the reconstructed three-dimensional finite model. The porosity at the crack tip is calculated using the damage constitutive model. The crack length is adjusted. When the porosity at the crack tip reaches the critical porosity, the corresponding crack length is the equivalent initial crack length of the defect.

7. The method for rapid prediction of the entire fatigue life of additive metals based on damage and fracture according to claim 6, characterized in that, Based on the equivalent initial crack length, a semi-analytical crack propagation algorithm is used to calculate the propagation process of surface cracks, embedded cracks, and corner cracks in the component, obtain the crack propagation life, and define the shortest crack propagation life as the final structural fatigue life. Based on the equivalent initial crack length, a semi-analytical crack propagation algorithm is used to calculate the propagation rate and direction of surface cracks, embedded cracks, and corner cracks. The stress intensity factor is quickly obtained using analytical formulas. Based on the stress intensity factor, the crack propagation amount is calculated using the crack propagation rate equation. A crack mode transformation rule is introduced. When the crack tip touches the free surface or component boundary, the crack type is immediately changed according to the preset rule, and the lifetime consumed by the crack transformation itself is ignored. When a crack penetrates the entire cross-section, failure is determined. The cumulative number of cycles is the crack propagation life corresponding to this dangerous defect, which is the final structural fatigue life.

8. A rapid prediction device for the entire fatigue life of additive metals based on damage and fracture, characterized in that, include: The data acquisition module performs non-destructive testing on additively manufactured metal components to obtain the three-dimensional geometric parameters of internal holes and defects; The hazardous defect selection module filters out multiple defects with the largest defect size as hazardous defects based on the three-dimensional geometric parameters. The critical load calculation module uses a damage constitutive model to calculate the porosity of each dangerous defect edge and obtain the critical load of the pore defect. The equivalent crack calculation module introduces an equivalent crack surface at the original location of the defect, and calculates the equivalent initial crack length based on the critical load of the hole defect using the damage constitutive model. The fatigue life acquisition module, based on the equivalent initial crack length, uses a semi-analytical crack propagation algorithm to calculate the propagation process of surface cracks, embedded cracks, and corner cracks in the component, obtains the crack propagation life, and defines the shortest crack propagation life as the final structural fatigue life.

9. An electronic device, characterized in that, include: A processor, and a memory communicatively connected to the processor; The memory stores computer-executed instructions; The processor executes computer execution instructions stored in the memory to implement the method as described in any one of claims 1-7.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer-executable instructions, which, when executed by a processor, are used to implement the method as described in any one of claims 1-7.

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