Method for predicting damage evolution and performance degradation of bonding interface under action of random load

Abstract

The invention discloses a method for predicting damage evolution and performance degradation of a bonding interface under the action of a random load, and belongs to the field of bonding interface damage prediction under the action of the random load. The method comprises the following steps: firstly, acquiring a random load signal in a cutting process of a bonding component, carrying out trend term removal processing on the random load signal, and extracting a characteristic section signal; secondly, processing the pre-simulation result of the bonding component to obtain the distribution range of the stress amplitude and frequency of the bonding interface; thirdly, carrying out a vibration load experiment on the standard butt joint bonding sample and the standard shear bonding sample to obtain S-N fatigue life curves in the normal stress direction and the shear stress direction and cohesion parameters after the bonding interface is degraded under different damage degrees; and finally, constructing a bonding component interface damage evolution and performance degradation prediction simulation model, and performing bonding interface damage prediction. The method can effectively predict the damage evolution process and the residual mechanical property of the bonding interface after the action of the high-frequency random vibration load, improves the calculation efficiency, and has guiding significance.

Description

Technical Field

[0001] This invention belongs to the field of adhesive interface damage prediction under random load, and relates to a method for predicting the damage evolution and performance degradation of adhesive interfaces under random load. Specifically, it relates to a method for predicting the damage evolution and performance degradation of adhesive interfaces under random load based on ABAQUS secondary development. Background Technology

[0002] Today, driven by the demand for lightweight manufacturing in high-end industries, bonding technology, with its advantages such as high specific strength and uniform stress distribution, is widely used in aerospace, electronics, and other fields. In the field of precision manufacturing, to ensure the machining accuracy of bonded components, a process flow of bonding first and then machining is usually adopted. However, the random cutting loads generated during the machining process can lead to the accumulation of damage at the bonded interface, thereby affecting the mechanical properties and structural reliability of the bonded components. Therefore, in-depth research on this issue is of great significance for optimizing machining parameters and improving the reliability of bonded components.

[0003] Currently, there is relatively little research on the damage evolution law of the bonding interface under random loads. Most studies focus on the degradation of the interface's mechanical properties under humid heat aging, such as the test method and coupling model for aging and creep damage of the bonding interface of a solid rocket engine disclosed in Chinese invention patent (202410863286.X); and interface fatigue life prediction models under low-frequency constant amplitude loads, such as the multi-axis variable amplitude thermomechanical fatigue life prediction method based on critical surface damage disclosed in Chinese invention patent (201911338597.X). Moreover, most of these studies do not consider the degradation of the interface's mechanical properties under alternating cyclic loads.

[0004] Therefore, a method for predicting the damage evolution and performance degradation of adhesive interfaces that is applicable to high-frequency random loads and considers the degradation of interfacial mechanical properties is needed. Summary of the Invention

[0005] To address the problems existing in the prior art, this invention proposes a method for predicting the damage evolution and performance degradation of the bonding interface under random loading. This invention can predict the degree of damage to the bonding interface during the entire random loading process by inputting characteristic segment signals into the finite element model.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A method for predicting the damage evolution and performance degradation of adhesive interfaces under random loading includes the following steps:

[0008] The first step is to acquire random load signals during the machining process of the bonded components, perform detrending term processing on the random load signals, and extract feature segment signals. Specifically:

[0009] Step 1.1: Collect random load signals in three coordinate directions during the cutting process using a coordinate measuring machine to obtain the original random load signals;

[0010] Step 1.2: Perform detrending data processing on the original random load signals in the three coordinate directions obtained in Step 1.1 to solve the zero-point drift problem that occurred during the acquisition process.

[0011] Step 1.3: Extract feature segment signals from the random load signals in the three coordinate directions obtained after the trend term removal process in Step 1.2. Since the tool cutting path is cyclical, it is only necessary to extract the random load signal from one cycle as the feature segment signal.

[0012] The second step involves establishing a pre-simulation model of the bonded component based on measured random load signals as boundary conditions, since the stress distribution at the bonding interface cannot be directly measured using a coordinate measuring machine. This model aims to obtain the stress response at the bonding interface, without considering damage or degradation at the interface. The pre-simulation results are then analyzed in the time and frequency domains using rainflow counting and power spectral density methods to determine the distribution range of stress amplitude and frequency at the bonding interface. Specifically:

[0013] Step 2.1 involves preprocessing the pre-simulation model of the bonded component, specifically as follows:

[0014] Step 2.1.1: Draw the geometric model of the bonded component;

[0015] Step 2.1.2: Mesh the geometric model of the bonded component obtained in Step 2.1.1 to obtain a mesh model;

[0016] Step 2.1.3: Define the material properties of the mesh model obtained in Step 2.1.2, set the bonding interface as a cohesive element and adopt a bilinear cohesive constitutive model, while the component matrix uses solid elements.

[0017] Step 2.1.4: Create an analysis step and set the required output variables;

[0018] Step 2.1.5: Set constraints and contacts according to the stress conditions during the actual processing of the bonded components;

[0019] Step 2.1.6: Set the boundary conditions of the mesh model and use the characteristic segment signal as the load application condition to obtain the pre-simulation model of the bonded component.

[0020] Step 2.2: Post-process the pre-simulation model of the bonded component to obtain the simulation results;

[0021] Step 2.3: Perform rainflow counting and power spectral density analysis on the simulation results of the pre-simulation model of the bonded component in Step 2.2 to obtain the distribution range of stress amplitude and frequency at the bonded interface.

[0022] The third step involves conducting vibration load tests on standard butt-bonded specimens and standard shear-bonded specimens based on the distribution range of stress amplitude and frequency at the bonding interface obtained in the second step. This yields the SN fatigue life curves in the normal stress direction and the SN fatigue life curves in the shear stress direction, as well as the cohesive force parameters after bonding interface degradation under different damage levels. Specifically:

[0023] Step 3.1: Since the random load signal is a high-frequency cutting force signal, referring to the adhesive tensile and shear strength determination standards GB / T 6329-1996 and GB / T 7124-2008, this invention designs standard butt bonding specimens and standard shear bonding specimens that can be used with a high-frequency vibration test bench. All specimens are prepared according to the specified bonding process.

[0024] Step 3.2 involves conducting fatigue tests on the standard butt-bonded specimens and the standard shear-bonded specimens under different stress amplitudes, specifically as follows:

[0025] Step 3.2.1: Based on the stress amplitude distribution range obtained by the rainflow counting method, divide it into several stress amplitude gradients, and separate the normal stress direction and the shear stress direction.

[0026] Step 3.2.2: Based on the power spectral density analysis results, select the frequency with the largest energy proportion as the fatigue loading frequency, and perform the normal stress direction and shear stress direction separately;

[0027] Step 3.2.3: Based on the experimental conditions set in Steps 3.2.1 and 3.2.2, conduct vibration fatigue tests on standard butt-bonded specimens and standard shear-bonded specimens, and plot the SN fatigue life curves in the normal stress direction and the SN fatigue life curves in the shear stress direction, respectively.

[0028] Step 3.3 involves testing the cohesive force parameters of standard butt-bonded specimens and standard shear-bonded specimens after degradation under different degrees of damage. Specifically:

[0029] Step 3.3.1: Based on the stress amplitude distribution range obtained by the rainflow counting method, select the stress amplitude with the largest proportion in the normal stress direction and the shear stress direction respectively, and use the stress amplitude and the frequency selected in step 3.2.2 as the vibration loading condition;

[0030] Step 3.3.2, based on Miner's theory and SN fatigue life curves, proposes a method using pre-set damage to test the cohesive force parameters of standard butt-bonded specimens and standard shear-bonded specimens after degradation under different damage levels. The Miner's theory calculation formula is as follows:

[0031]

[0032] in, for The actual number of cycles at the stress level; The fatigue life under the corresponding stress level is obtained from the SN fatigue life curve; Indicates the cumulative damage value. Fatigue failure occurs at this time; Indicates the stress level number, This represents the total stress level number;

[0033] Step 3.3.3 involves testing the cohesive force parameters of standard butt-bonded samples after degradation under different degrees of damage. Specifically:

[0034] Step 3.3.3.1: Under the same stress amplitude and frequency, pre-determine the damage to the standard butt joint bonded specimens with different number of cycles;

[0035] Step 3.3.3.2: By testing the residual mechanical properties of standard butt-bonded samples with different degrees of damage, the cohesive force parameters in the normal stress direction after the bonding interface degrades are obtained.

[0036] Step 3.3.4 involves testing the cohesive force parameters of standard shear-bonded specimens after degradation under different degrees of damage. Specifically:

[0037] Step 3.3.4.1: Under the same stress amplitude and frequency, pre-determine the damage to the standard shear bonded specimen with different number of cycles;

[0038] Step 3.3.4.2: By testing the residual mechanical properties of standard shear-bonded specimens with different degrees of damage, the cohesive force parameters in the shear stress direction after the bonding interface degrades are obtained.

[0039] The fourth step involves constructing a simulation model for predicting the interface damage evolution and performance degradation of bonded components based on the normal stress direction SN fatigue life curves and shear stress direction SN fatigue life curves obtained in the third step, as well as the cohesive parameters in the normal stress direction and shear stress direction after the bonding interface degrades under different damage levels. This model is used to predict the bonding interface damage. Specifically:

[0040] Step 4.1 involves preprocessing the simulation model for predicting the interface damage evolution and performance degradation of bonded components. Specifically:

[0041] Step 4.1.1 defines the material properties of the mesh model obtained in Step 2.1.2. The bonding interface is set as a cohesive element using a bilinear cohesive constitutive model, while the matrix portion of the component uses solid elements. Field variables also need to be set. The number of, and define and These refer to the damage values ​​in the directions of normal stress and shear stress, respectively.

[0042] Step 4.1.2: Create an analysis step and set the required output variables;

[0043] Step 4.1.3: Set constraints and contacts according to the stress conditions of the actual processing of the bonded components;

[0044] Step 4.1.4: Set the boundary conditions of the mesh model and use the characteristic segment signal as the load application condition.

[0045] Step 4.2: Based on the ABAQUS secondary development method for predicting the damage evolution and performance degradation of the bonding interface under random load, the interface damage is calculated, specifically as follows:

[0046] Step 4.2.1 proposes a novel damage calculation method. During the implementation of the simulation model for predicting the interface damage evolution and performance degradation of bonded components, damage calculations based on Miner's theory and the SN fatigue life curve are performed at short intervals. This method is called "inter-interval rainflow counting method damage calculation." The time interval for the inter-interval rainflow counting method is set according to the characteristic segment signal duration and load frequency. Second;

[0047] Step 4.2.2, every Trigger a small-interval rain flow counting statistics once per second, and count the stress amplitude of the material integration points of the cohesive unit within the bonding interface.

[0048] Step 4.2.3: Perform rainflow counting statistics on the stress-time history data in the normal stress direction;

[0049] Step 4.2.4: Calculate the damage in the normal stress direction based on Miner's theory and multiply by the corresponding amplification factor. Adding the amplification factor allows for the prediction of damage caused by the load throughout the cutting process using the characteristic segment signal. The corresponding amplification factor... =Effective cutting time throughout the entire process / Signal time of the characteristic segment;

[0050] Step 4.2.5: Perform rainflow counting on the stress-time history data in the shear stress direction and calculate the damage in this interval. In the local coordinate system of the cohesive unit at the adhesive interface, there are two shear stress directions, shear stress-1 and shear stress-2, which are perpendicular to each other, specifically:

[0051] Step 4.2.5.1: Perform rainflow counting statistics on the shear stress in the -1 direction;

[0052] Step 4.2.5.2: Calculate the damage in the shear stress -1 direction based on Miner's theory, and multiply by the corresponding amplification factor. ;

[0053] Step 4.2.5.3: Perform rainflow counting statistics on the shear stress in the -2 direction;

[0054] Step 4.2.5.4: Calculate the damage in the -2 direction of shear stress based on Miner's theory, and multiply by the corresponding amplification factor. .

[0055] Step 4.2.6: After calculating the damage in different directions, it is necessary to perform a progressively cumulative calculation. The calculation formula is as follows: .in, The interval damage values ​​calculated based on the inter-interval rainflow counting method are used in this study. The cumulative damage value from the previous step, This is the updated cumulative damage value;

[0056] Step 4.2.7, for the total damage in both shear stress directions Through the formula: Calculation. Among them, Damage in the shear stress-1 direction Damage in the shear stress -2 direction Total damage in the direction of shear stress;

[0057] Step 4.2.8, for Total damage Assign values ​​to the field variables respectively and ,in, This indicates damage in the direction of normal stress. (Through...) and Changes in field variable values ​​degrade the cohesive parameters of the corresponding cohesive elements. Among them, Damage is in the direction of normal stress. This represents the total damage in the direction of shear stress.

[0058] Step 4.2.9, The total damage from normal stress and shear stress is calculated using the following formula: ;

[0059] Step 4.2.10, if the current analysis step time +Time interval Total Time If the simulation ends, proceed to step 4.3; otherwise, return to step 4.2.3.

[0060] Step 4.3: Post-process the interface damage model of the bonded component under random load, and extract the total average damage value or local damage value of the bonded interface as an indicator to evaluate the interface damage.

[0061] The beneficial effects of this invention are as follows:

[0062] (1) The model established in this invention can effectively predict the damage evolution process and residual mechanical properties of the bonding interface after high-frequency random vibration load.

[0063] (2) The present invention uses characteristic segment signals to predict the degree of interface damage during the entire loading process, which effectively improves computational efficiency;

[0064] (3) This invention has guiding significance for evaluating the degree and evolution of interface damage under different random vibration loads, analyzing the sensitivity of process parameters and optimizing processing parameters. Attached Figure Description

[0065] Figure 1 The graph shows the original collected data in the X, Y, and Z directions, and the results after detrending. Figure 1 (a) Figure 1 In the diagram, (b) represents the original X-axis data and the data after the trend item, respectively. Figure 1 (c) Figure 1 In the table, (d) represents the original Y-axis data and the data after the trend item, respectively. Figure 1 (e) Figure 1 In the table, (f) represents the original data for the Z-axis and the data following the trend, respectively.

[0066] Figure 2 Time-domain and frequency-domain analysis diagrams of the pre-simulation results of the bonded components; Figure 2 (a) in the figure is a stress amplitude distribution diagram from the statistical results of the rainflow counting method. Figure 2 (b) in the figure is a three-dimensional bar chart of amplitude-mean-cycle count from the statistical results of the rainflow counting method. Figure 2 (c) in the figure is the power spectral density (PSD) curve.

[0067] Figure 3 Schematic diagrams of standard butt bonding specimens and standard shear bonding specimens; Figure 3 (a) in the figure is a standard butt bonding sample. Figure 3 (b) in the sample is a standard shear-bonded specimen.

[0068] Figure 4 This is a schematic diagram of the amplification factor in secondary development.

[0069] Figure 5The process of modeling the damage of the adhesive interface under random load.

[0070] Figure 6 Simulation cloud map of damage at the bonding interface; Figure 6 (a) in the diagram is a stress damage contour map in the direction of normal stress; Figure 6 (b) in the diagram is a stress contour plot showing the direction of shear stress. Figure 6 (c) in the diagram represents the overall damage contour map.

[0071] Figure 7 The output curve shows the total damage-time history of the bonding interface. Detailed Implementation

[0072] The present invention will be further described below with reference to the accompanying drawings. The present invention is based on simulation data of interface damage evolution of metal bonded components under random cutting load.

[0073] The first step is to acquire random load signals during the machining process of the bonded components, perform detrending term processing on the random load signals, and extract feature segment signals. Specifically:

[0074] Step 1.1: Collect random load signals in three coordinate directions during the cutting process using a coordinate measuring machine to obtain the original random load signals;

[0075] Step 1.2 involves performing detrending data processing on the original random load signals in the three coordinate directions obtained in Step 1.1 to address the zero-point drift problem that occurred during the acquisition process. The processing results are as follows: Figure 1 ;

[0076] Step 1.3: Extract feature segment signals from the random load signals in the three coordinate directions obtained after the trend term removal process in Step 1.2. Since the tool cutting path is cyclical, it is only necessary to extract the random load signal from one cycle as the feature segment signal.

[0077] The second step involves establishing a pre-simulation model of the bonded component based on measured random load signals as boundary conditions, since the stress distribution at the bonding interface cannot be directly measured using a coordinate measuring machine. This model aims to obtain the stress response at the bonding interface, without considering damage or degradation at the interface. The pre-simulation results are then analyzed in the time and frequency domains using rainflow counting and power spectral density methods to determine the distribution range of stress amplitude and frequency at the bonding interface. Specifically:

[0078] Step 2.1 involves preprocessing the pre-simulation model of the bonded component, specifically as follows:

[0079] Step 2.1.1: Draw the geometric model of the bonded component;

[0080] Step 2.1.2: Mesh the geometric model of the bonded component obtained in Step 2.1.1 to obtain a mesh model;

[0081] Step 2.1.3: Define the material properties of the mesh model obtained in Step 2.1.2, set the bonding interface as a cohesive element and adopt a bilinear cohesive constitutive model, while the component matrix uses solid elements.

[0082] Step 2.1.4: Create an analysis step and set the required output variables;

[0083] Step 2.1.5: Set constraints and contacts according to the stress conditions during the actual processing of the bonded components;

[0084] Step 2.1.6: Set the boundary conditions of the mesh model and use the characteristic segment signal as the load application condition.

[0085] Step 2.2: Post-process the pre-simulation model of the bonded component to obtain the simulation results;

[0086] Step 2.3 involves performing rainflow counting and power spectral density analysis on the simulation results of the pre-simulation model of the bonded component from Step 2.2 to obtain the distribution range of stress amplitude and frequency at the bonded interface. The analysis results are as follows: Figure 2 This section only shows one direction of shear stress; the method does not consider the influence of the mean value.

[0087] The third step involves conducting vibration load tests on standard butt-bonded specimens and standard shear-bonded specimens based on the distribution range of stress amplitude and frequency at the bonding interface obtained in the second step. This yields the SN fatigue life curves in the normal stress direction and the SN fatigue life curves in the shear stress direction, as well as the cohesive force parameters after bonding interface degradation under different damage levels. Specifically:

[0088] Step 3.1: Since the random load signal is a high-frequency cutting force signal, referring to the adhesive tensile and shear strength determination standards GB / T 6329-1996 and GB / T 7124-2008, this invention designs standard butt bonding specimens and standard shear bonding specimens that can be used with a high-frequency vibration test bench. All specimens are prepared according to the specified bonding process. The three-dimensional model is as follows: Figure 3 ;

[0089] Step 3.2 involves conducting fatigue tests on the standard butt-bonded specimens and the standard shear-bonded specimens under different stress amplitudes, specifically as follows:

[0090] Step 3.2.1: Based on the stress amplitude distribution range obtained by the rainflow counting method, divide it into several stress amplitude gradients, and separate the normal stress direction and the shear stress direction.

[0091] Step 3.2.2: Based on the power spectral density analysis results, select the frequency with the largest energy proportion as the fatigue loading frequency, and perform the normal stress direction and shear stress direction separately;

[0092] Step 3.2.3: Based on the experimental conditions set in Steps 3.2.1 and 3.2.2, conduct vibration fatigue tests on standard butt-bonded specimens and standard shear-bonded specimens, and plot the SN fatigue life curves in the normal stress direction and the SN fatigue life curves in the shear stress direction, respectively.

[0093] Step 3.3 involves testing the cohesive force parameters of standard butt-bonded specimens and standard shear-bonded specimens after degradation under different degrees of damage. Specifically:

[0094] Step 3.3.1: Based on the stress amplitude distribution range obtained by the rainflow counting method, select the stress amplitude with the largest proportion in the normal stress direction and the shear stress direction respectively, and use the stress amplitude and the frequency selected in step 3.2.2 as the vibration loading condition;

[0095] Step 3.3.2, based on Miner's theory and SN fatigue life curves, proposes a method using pre-set damage to test the cohesive force parameters of standard butt-bonded specimens and standard shear-bonded specimens after degradation under different damage levels. The Miner's theory calculation formula is as follows:

[0096]

[0097] in, for The actual number of cycles at the stress level; The fatigue life under the corresponding stress level is obtained from the SN fatigue life curve; Indicates the cumulative damage value. Fatigue failure occurs; Indicates the stress level number, This represents the total stress level number;

[0098] Step 3.3.3 involves testing the cohesive force parameters of standard butt-bonded samples after degradation under different degrees of damage. Specifically:

[0099] In step 3.3.3.1, in the pre-simulation results of the bonded component under a certain working condition, 0.5 MPa is the stress amplitude in the main normal stress direction. Based on the fatigue life curve in step 3.2.3, the corresponding fatigue life can be obtained as 3,200,000. Referring to the actual number of times the stress amplitude of 0.5 MPa appears in the rainflow counting method, the maximum damage of the cohesive unit in the bonded interface during the entire random process is estimated. Through calculation, the estimated maximum damage is 0.25. Therefore, bonded interface damage preloading can be performed at a stress amplitude of 0.5 MPa and a frequency of 850 Hz, with 3,200,000 × 0.05, 3,200,000 × 0.15, and 3,200,000 × 0.25 cycles, corresponding to damage values ​​of 0.05, 0.15, and 0.25, respectively.

[0100] Step 3.3.3.2: Perform residual mechanical property tests on standard butt bonding specimens subjected to loading cycles of 160,000, 480,000, and 800,000 respectively to obtain the cohesive force parameters of the bonding interface after degradation under different damage levels in the normal stress direction.

[0101] Step 3.3.4 involves testing the cohesive force parameters of standard shear-bonded specimens after degradation under different degrees of damage. Specifically:

[0102] In step 3.3.3.1, in the pre-simulation results of the bonded component under a certain working condition, 0.6 MPa is the stress amplitude in the main shear stress direction. Based on the fatigue life curve in step 3.2.3, the corresponding fatigue life of 4,600,000 can be obtained. Referring to the actual number of times the stress amplitude of 0.6 MPa appears in the rainflow counting method, the maximum damage of the cohesive unit in the bonded interface during the entire random process is estimated. If the estimated maximum damage is 0.3, then bonded interface damage preloading can be performed at a stress amplitude of 0.6 MPa and a frequency of 850 Hz, with 4,600,000 × 0.10, 4,600,000 × 0.20, and 4,600,000 × 0.30 cycles, with corresponding damage values ​​of 0.05, 0.15, and 0.25, respectively.

[0103] Step 3.3.3.2 involves testing the residual mechanical properties of standard shear-bonded specimens subjected to loading cycles of 460,000, 920,000, and 1,380,000, respectively, to obtain the cohesive force parameters of the bond interface after degradation under different damage levels in the shear stress direction.

[0104] The fourth step involves constructing a simulation model for predicting the interface damage evolution and performance degradation of bonded components based on the normal stress direction SN fatigue life curves and shear stress direction SN fatigue life curves obtained in the third step, as well as the cohesive parameters in the normal stress direction and shear stress direction after the bonding interface degrades under different damage levels. This model is used to predict the bonding interface damage. Specifically:

[0105] Step 4.1 involves preprocessing the simulation model for predicting the interface damage evolution and performance degradation of bonded components. Specifically:

[0106] Step 4.1.1 defines the material properties of the mesh model obtained in Step 2.1.2. The bonding interface is set as a cohesive element using a bilinear cohesive constitutive model, while the matrix portion of the component uses solid elements. Field variables also need to be set. The number of, and define and These refer to the damage values ​​in the directions of normal stress and shear stress, respectively.

[0107] Step 4.1.2: Create an analysis step and set the required output variables;

[0108] Step 4.1.3: Set constraints and contacts according to the stress conditions of the actual processing of the bonded components;

[0109] Step 4.1.4: Set the boundary conditions of the mesh model and use the characteristic segment signal as the load application condition.

[0110] Step 4.2: Based on the ABAQUS secondary development method for predicting the damage evolution and performance degradation of the bonding interface under random load, the interface damage is calculated, specifically as follows:

[0111] Step 4.2.1 proposes a novel damage calculation method. During the implementation of the simulation model for predicting the interface damage evolution and performance degradation of bonded components, damage calculations based on Miner's theory and the SN fatigue life curve are performed at short intervals. This method is called "inter-interval rainflow counting method damage calculation." The time interval for the inter-interval rainflow counting method is set according to the characteristic segment signal duration and load frequency. Second;

[0112] Step 4.2.2, every Trigger a small-interval rain flow counting statistics once per second, and count the stress amplitude of the material integration points of the cohesive unit within the bonding interface.

[0113] Step 4.2.3: Perform rainflow counting statistics on the stress-time history data in the normal stress direction;

[0114] Step 4.2.4: Calculate the damage in the normal stress direction based on Miner's theory and multiply by the corresponding amplification factor. Adding the amplification factor allows for the prediction of damage caused by the load throughout the cutting process using the characteristic segment signal. The corresponding amplification factor... =Total effective cutting time / Feature segment signal time, as shown in the magnified schematic diagram. Figure 4 ;

[0115] Step 4.2.5: Perform rainflow counting on the stress-time history data in the shear stress direction and calculate the damage in this interval. In the local coordinate system of the cohesive unit at the adhesive interface, there are two shear stress directions, shear stress-1 and shear stress-2, which are perpendicular to each other, specifically:

[0116] Step 4.2.5.1: Perform rainflow counting statistics on the shear stress in the -1 direction;

[0117] Step 4.2.5.2: Calculate the damage in the shear stress -1 direction based on Miner's theory, and multiply by the corresponding amplification factor. ;

[0118] Step 4.2.5.3: Perform rainflow counting statistics on the shear stress in the -2 direction;

[0119] Step 4.2.5.4: Calculate the damage in the -2 direction of shear stress based on Miner's theory, and multiply by the corresponding amplification factor. .

[0120] Step 4.2.6: After calculating the damage in different directions, it is necessary to perform a progressively cumulative calculation. The calculation formula is as follows: .in, The interval damage values ​​calculated based on the inter-interval rainflow counting method are used in this study. The cumulative damage value from the previous step, This is the updated cumulative damage value;

[0121] Step 4.2.7, for the total damage in both shear stress directions Through the formula: Calculation. Among them, Damage in the shear stress-1 direction Damage in the shear stress -2 direction Total damage in the direction of shear stress;

[0122] Step 4.2.8, for Total damage Assign values ​​to the field variables respectively and ,in, This indicates damage in the direction of normal stress. (Through...) and Changes in field variable values ​​degrade the cohesive parameters of the corresponding cohesive elements. Among them, Damage is in the direction of normal stress. This represents the total damage in the direction of shear stress.

[0123] Step 4.2.9, The total damage from normal stress and shear stress is calculated using the following formula: ;

[0124] Step 4.2.10, if the current analysis step time +Time interval Total Time If the simulation ends, proceed to step 4.3; otherwise, return to step 4.2.3.

[0125] Step 4.3 involves post-processing the interface damage model of the bonded component under random loads, extracting the total average damage value or local damage value of the bonded interface as an indicator for evaluating the interface damage. Figure 5 This describes the process of modeling damage at the adhesive interface under random loading. Figure 6 For simulation cloud map of adhesive interface damage, Figure 7 This is the output curve of the total damage history of the bonding interface.

[0126] The embodiments described above are merely illustrative of implementation methods of the present invention and should not be construed as limiting the scope of the invention. Those skilled in the art can make variations and improvements to the interface damage evolution and performance degradation prediction methods without departing from the concept of the present invention, including but not limited to adhesive interfaces; these all fall within the protection scope of the present invention.

Claims

1. A method for predicting the damage evolution and performance degradation of adhesive interfaces under random loading, characterized in that, Includes the following steps: The first step is to collect random load signals during the cutting process of the bonded components, perform detrending term processing on the random load signals, and extract feature segment signals. The second step involves using rainflow counting and power spectral density to perform time-domain and frequency-domain analyses on the pre-simulation results of the bonded components, respectively, to obtain the distribution range of stress amplitude and frequency at the bonded interface. The third step involves conducting vibration load tests on standard butt bonding specimens and standard shear bonding specimens based on the distribution range of stress amplitude and frequency at the bonding interface obtained in the second step. This yields the SN fatigue life curves in the normal stress direction and the SN fatigue life curves in the shear stress direction, as well as the cohesive force parameters after bonding interface degradation under different damage levels. The fourth step involves constructing a simulation model for predicting the interface damage evolution and performance degradation of bonded components based on the normal stress direction SN fatigue life curves and shear stress direction SN fatigue life curves obtained in the third step, as well as the cohesive parameters in the normal stress direction and shear stress direction after the bonding interface degrades under different damage levels. This model is used to predict the bonding interface damage.

2. The method for predicting the damage evolution and performance degradation of adhesive interfaces under random loading as described in claim 1, characterized in that, The first step is specifically as follows: Step 1.1: Collect random load signals in three coordinate directions during the cutting process using a coordinate measuring machine to obtain the original random load signals; Step 1.2: Perform detrending data processing on the original random load signals in the three coordinate directions obtained in Step 1.1 to solve the zero-point drift problem that occurred during the acquisition process. Step 1.3: Extract feature segment signals from the random load signals in the three coordinate directions obtained after the trend term removal process in Step 1.2; extract only the random load signal in one cycle as the feature segment signal.

3. The method for predicting the damage evolution and performance degradation of the adhesive interface under random loading as described in claim 2, characterized in that, The second step is specifically as follows: Step 2.1 involves preprocessing the pre-simulation model of the bonded component, specifically as follows: Step 2.1.1: Draw the geometric model of the bonded component; Step 2.1.2: Mesh the geometric model of the bonded component to obtain a mesh model; Step 2.1.3: Define the material properties of the mesh model, set the bonding interface as a cohesive element and adopt a bilinear cohesive constitutive model, and use solid elements for the component matrix. Step 2.1.4: Create an analysis step and set the required output variables; Step 2.1.5: Set constraints and contacts according to the stress conditions during the actual processing of the bonded components; Step 2.1.6: Set the boundary conditions of the mesh model and use the characteristic segment signal as the load application condition to obtain the pre-simulation model of the bonded component; Step 2.2: Post-process the pre-simulation model of the bonded component to obtain the simulation results; Step 2.3: Perform rainflow counting and power spectral density analysis on the simulation results of the pre-simulation model of the bonded component to obtain the distribution range of stress amplitude and frequency at the bonding interface.

4. The method for predicting the damage evolution and performance degradation of the adhesive interface under random loading as described in claim 3, characterized in that, The third step is specifically as follows: Step 3.1: Design standard butt bonding specimens and standard shear bonding specimens that can be used with a high-frequency vibration test bench; Step 3.2 involves conducting fatigue tests on the standard butt-bonded specimens and the standard shear-bonded specimens under different stress amplitudes, specifically as follows: Step 3.2.1: Based on the stress amplitude distribution range obtained by the rainflow counting method, divide it into several stress amplitude gradients, and separate the normal stress direction and the shear stress direction. Step 3.2.2: Based on the power spectral density analysis results, select the frequency with the largest energy proportion as the fatigue loading frequency, and perform the normal stress direction and shear stress direction separately; Step 3.2.3: Conduct vibration fatigue tests on standard butt-bonded specimens and standard shear-bonded specimens to obtain the SN fatigue life curves in the normal stress direction and the SN fatigue life curves in the shear stress direction. Step 3.3 involves testing the cohesive force parameters of standard butt-bonded specimens and standard shear-bonded specimens after degradation under different degrees of damage. Specifically: Step 3.3.1: Based on the stress amplitude distribution range obtained by the rainflow counting method, select the stress amplitude with the largest proportion in the normal stress direction and the shear stress direction respectively, and use the stress amplitude and the frequency selected in step 3.2.2 as the vibration loading condition; Step 3.3.2, based on Miner theory and SN fatigue life curve, proposes a method with preset damage to test the cohesive force parameters of standard butt bonded specimens and standard shear bonded specimens after degradation under different damage degrees. Step 3.3.3: Test the cohesive force parameters of the standard butt bonding specimens after degradation under different damage levels to obtain the cohesive force parameters in the normal stress direction after the bonding interface is degraded. Step 3.3.4: Test the cohesive force parameters of the standard shear bonded specimens after degradation under different damage levels to obtain the cohesive force parameters in the shear stress direction after the bonding interface has degraded.

5. The method for predicting the damage evolution and performance degradation of the adhesive interface under random loading as described in claim 4, characterized in that, In step 3.1, the standard butt bonding specimen and the standard shear bonding specimen are prepared according to the specified bonding process.

6. The method for predicting the damage evolution and performance degradation of the adhesive interface under random loading as described in claim 4, characterized in that, In step 3.3.2, the Miner theoretical calculation formula is as follows: in, for The actual number of cycles at the stress level; The fatigue life under the corresponding stress level is obtained from the SN fatigue life curve; Indicates the cumulative damage value. Fatigue failure occurs at this time; Indicates the stress level number, This represents the total stress level.

7. The method for predicting the damage evolution and performance degradation of the adhesive interface under random loading as described in claim 4, characterized in that, In step 3.3: Step 3.3.3 specifically involves: Step 3.3.3.1: Under the same stress amplitude and frequency, pre-determine the damage to the standard butt joint bonded specimens with different number of cycles; Step 3.3.3.2: By testing the residual mechanical properties of standard butt bonding samples with different degrees of damage, the cohesive force parameters in the normal stress direction after the bonding interface degrades are obtained. Step 3.3.4 specifically involves: Step 3.3.4.1: Under the same stress amplitude and frequency, pre-determine the damage to the standard shear bonded specimen with different number of cycles; Step 3.3.4.2: By testing the residual mechanical properties of standard shear-bonded specimens with different degrees of damage, the cohesive force parameters in the shear stress direction after the bonding interface degrades are obtained.

8. The method for predicting the damage evolution and performance degradation of the adhesive interface under random loading as described in claim 7, characterized in that, The fourth step specifically involves: Step 4.1 involves preprocessing the simulation model for predicting the interface damage evolution and performance degradation of bonded components. Specifically: Step 4.1.1: Define the material properties of the mesh model obtained in Step 2.1.

2. Set the bonding interface as a cohesive element and use a bilinear cohesive constitutive model. Use solid elements for the matrix part of the component. Simultaneously, set the field variables. The number of, and define and These refer to the damage values ​​in the directions of normal stress and shear stress, respectively. Step 4.1.2: Create an analysis step and set the required output variables; Step 4.1.3: Set constraints and contacts according to the stress conditions of the actual processing of the bonded components; Step 4.1.4: Set the boundary conditions of the mesh model and use the characteristic segment signal as the load application condition; Step 4.2: Based on the method for predicting the evolution of adhesive interface damage and performance degradation under random loads developed in ABAQUS secondary development, perform interface damage calculation; Step 4.3: Post-process the interface damage model of the bonded component under random load, and extract the total average damage value or local damage value of the bonded interface as an indicator to evaluate the interface damage.

9. The method for predicting the damage evolution and performance degradation of the adhesive interface under random loading as described in claim 8, characterized in that, Step 4.2 specifically refers to: Step 4.2.1 proposes a damage calculation method. During the implementation of the simulation model for predicting the interface damage evolution and performance degradation of bonded components, damage calculations based on Miner's theory and the SN fatigue life curve are performed at short intervals. This is called the inter-interval rainflow counting method damage calculation. The time interval for the inter-interval rainflow counting method is set according to the characteristic segment signal duration and load frequency. Second; Step 4.2.2, every Trigger a small-interval rain flow counting statistics once per second, and count the stress amplitude of the material integration points of the cohesive unit within the bonding interface. Step 4.2.3: Perform rainflow counting statistics on the stress-time history data in the normal stress direction; Step 4.2.4: Calculate the damage in the normal stress direction based on Miner's theory and multiply it by the corresponding amplification factor. Step 4.2.5: Perform rainflow counting on the stress-time history data in the shear stress direction and calculate the damage in this interval. In the local coordinate system of the cohesive unit at the adhesive interface, there are two shear stress directions, shear stress-1 and shear stress-2, which are perpendicular to each other, specifically: Step 4.2.5.1: Perform rainflow counting statistics on the shear stress in the -1 direction; Step 4.2.5.2: Calculate the damage in the shear stress -1 direction based on Miner's theory, and multiply by the corresponding amplification factor. ; Step 4.2.5.3: Perform rainflow counting statistics on the shear stress in the -2 direction; Step 4.2.5.4: Calculate the damage in the -2 direction of shear stress based on Miner's theory, and multiply by the corresponding amplification factor. ; Step 4.2.6: After calculating the damage in different directions, it is necessary to perform a progressively cumulative calculation. The calculation formula is as follows: ;in, The interval damage values ​​calculated based on the inter-interval rainflow counting method are used in this study. The cumulative damage value from the previous step, This is the updated cumulative damage value; Step 4.2.7, for the total damage in both shear stress directions Through the formula: Calculate; where, Damage in the shear stress-1 direction Damage in the shear stress -2 direction Total damage in the direction of shear stress; Step 4.2.8, for Total damage Assign values ​​to the field variables respectively and ,in, Indicates damage in the direction of normal stress; through and Changes in field variable values ​​respectively degenerate the cohesive parameters of the corresponding cohesive elements; among them... Damage is in the direction of normal stress. This represents the total damage in the direction of shear stress. Step 4.2.9, The total damage from normal stress and shear stress is calculated using the following formula: ; Step 4.2.10, if the current analysis step time +Time interval Total Time If the simulation ends, proceed to step 4.3; otherwise, return to step 4.2.

3.

10. The method for predicting the damage evolution and performance degradation of adhesive interfaces under random loading as described in claim 9, characterized in that, In step 4.2.4, the corresponding amplification factor is applied. =Effective cutting time throughout the entire process / Signal time of the characteristic segment.

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