A method for simulating the polishing process of core-shell composite abrasives

Abstract

The present invention relates to a method for simulating the polishing process of core-shell composite abrasive grains, and the analysis steps are as follows: establishing a workpiece model and setting microscopic parameters for the workpiece model; establishing a core-shell composite abrasive grain model and setting the attributes and parameters of the core-shell composite abrasive grain model; integrating the workpiece model and the core-shell composite abrasive grain model together to establish a core-shell composite abrasive grain polishing workpiece model; setting the impact parameters of the core-shell composite abrasive grains to simulate the polishing process; and performing statistical analysis on the damage and impact damage of the core-shell composite abrasive grains. The present invention has the following technical effects: by using the core-shell composite abrasive grains to polish the workpiece, a composite abrasive grain model of "core-interface-shell" is established; the damage of the core-shell composite abrasive grains and the impact damage of the workpiece during the polishing process are visualized by using the discrete element simulation method, and the damage of the core-shell composite abrasive grains and the impact damage of the workpiece can be intuitively observed.

Description

Technical Field

[0001] The present invention relates to a method for simulating the polishing process of core-shell composite abrasive grains, belonging to the technical field of precision machining of composite abrasive grains. Technical Background

[0002] In view of the "hard" impact on the workpiece surface caused by traditional inorganic abrasive grains driven by the ultrasonic cavitation effect, problems such as large scratches, cracks and pits are likely to occur. The core-shell composite abrasive grains proposed this time use a polymer with better elasticity as the core and an inorganic material as the coating layer, effectively reducing the impact damage of the abrasive grains on the workpiece surface.

[0003] The present invention provides a method for simulating the polishing process of core-shell composite abrasive grains. From the literature that has been mastered, there has been no report on the simulation of the destruction of core-shell composite abrasive grains and the impact damage of workpieces during the polishing process of core-shell composite abrasive grains using the discrete element method. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for simulating the polishing process of core-shell composite abrasive grains, which can simulate the polishing process of core-shell composite abrasive grains and conduct statistical analysis on the destruction of core-shell composite abrasive grains and the impact damage of workpieces.

[0005] To achieve the purpose of the present invention, the technical solution of the present invention provides a method for simulating the polishing process of core-shell composite abrasive grains, specifically including: S1: Establish a workpiece model and set microscopic parameters for the workpiece model; S2: Establish a core-shell composite abrasive grain model and set the attributes and parameters of the core-shell composite abrasive grain model; S3: Integrate the workpiece model and the core-shell composite abrasive grain model to establish a core-shell composite abrasive grain polishing workpiece model; S4: Set the impact parameters of the core-shell composite abrasive grains and simulate the polishing process; S5: Conduct statistical analysis on the destruction of the core-shell composite abrasive grains and the impact damage of the workpiece.

[0006] In this technical solution, the discrete element method is used to simulate the impact damage of the workpiece during the polishing process of the core-shell composite abrasive grains on the workpiece, capture several model states during the process of the core-shell composite abrasive grains impacting the workpiece, and visually observe the destruction of the core-shell composite abrasive grains and the impact damage of the workpiece during the polishing process.

[0007] In addition, the technical solution provided by the present invention may also have the following additional technical features:

[0008] In the above technical solution, a workpiece model is established, and microscopic parameters are set for the workpiece model, specifically including: S1101: Set the size of the first region, and generate particles according to the first region; S1102: Set the size of the first wall region; S1103: Set the first radius, the first porosity, the first density, and the first damping of the particles; S1104: Appropriately increase the radius of the workpiece particles; S1105: Adjust the radius of the floating particles with a contact number less than 3; S1106: Set the first time for generating the particles, and establish the workpiece model; S1107: Add a Bonded Particle Model (BPM) for modeling, so that parallel bonds are generated between the workpiece particles, set the parameters of the parallel bonds between the workpiece particles, and add the first stiffness, the first normal-to-tangential stiffness ratio, the first friction coefficient, the first critical damping ratio, the first normal strength, the first cohesion, and the first friction angle to the workpiece model; S1108: Set the range of the bonding radius between the workpiece particles; S1109: Delete the first wall to make the model in a relaxed state, and obtain the BPM model of the workpiece.

[0009] This technical solution establishes a workpiece model and specifically sets the parameters of the polished workpiece model according to the actual situation, providing a data basis for subsequent simulations.

[0010] In any of the above technical solutions, establishing a core-shell composite abrasive model specifically includes: S2101: Establishing a shell model of the core-shell composite abrasive; S2102: Setting the size of the second region; S2103: Setting the size of the second wall region and generating shell particles in the second wall region; S2104: Setting the second radius, second porosity, second density, and second damping of the shell particles; S2105: Appropriately expanding the radius of the shell particles; S2106: Adjusting the radius of floating particles with a contact number less than 3; S2107: Setting the second time for generating the shell particles and establishing the shell model of the core-shell composite abrasive; S2108: Adding particle bonding model modeling to generate parallel bonds between the shell particles; S2109: Setting the parameters of the parallel bonds between the shell particles and adding the second stiffness, second normal-to-tangential stiffness ratio, second friction coefficient, second critical damping ratio, second normal strength, second cohesion, and second friction angle to the core-shell composite abrasive shell model; S2110: Setting the bonding radius range between the shell particles; S2111: Deleting the second wall to make the model in a relaxed state and obtaining the corresponding BPM model; S2112: Saving the shell file of the core-shell composite abrasive; S2201: Establishing a core model of the core-shell composite abrasive; S2202: Invoking the shell file of the core-shell composite abrasive; S2203: Setting the third radius, third porosity, third density, and third damping of the core particles; S2204: Setting the size of the third region and generating core particles according to the third region; S2205: Appropriately expanding the radius of the core particles; S2206: Adjusting the radius of floating particles with a contact number less than 3; S2207: Setting the third time for generating the core particles and establishing the core model of the core-shell composite abrasive; S2208: Adding particle bonding model modeling to generate parallel bonds between the core particles; S2209: Setting the parameters of the parallel bonds between the core particles and adding the third stiffness, third normal-to-tangential stiffness ratio, third friction coefficient, third critical damping ratio, third normal strength, third cohesion, and third friction angle to the core model; S2210: Setting the bonding radius range between the core particles; S2211: Obtaining the corresponding BPM model; S2301: Setting the interface layer contact parameters between the core and the shell of the core-shell composite abrasive model. For the bonding interface between the outer shell and the inner core of the core-shell composite abrasive, a displacement-softening contact model is adopted; S2401: Saving the core-shell composite abrasive model.

[0011] In this technical solution, by setting the shell abrasive model of the core-shell composite abrasive model and the core abrasive model of the core-shell composite abrasive model, the core abrasive and the shell abrasive are divided into two groups, and different attribute parameters are respectively assigned to the composite abrasive shell, core, and the interface between the core and the shell to represent the model of the core-shell composite abrasive, providing a data basis and theoretical foundation for subsequent simulations and enhancing the authenticity and effectiveness of the simulation results.

[0012] In any of the above technical solutions, the workpiece model and the core-shell type composite abrasive model are integrated together to establish a core-shell type composite abrasive polishing workpiece model, specifically including: S3101: deleting the first area size and deleting the second area size; S3102: establishing the fourth area size; S3103: determining the workpiece coordinate position; S3104: calling the workpiece model; S3105: determining the coordinate position of the core-shell type composite abrasive; S3106: calling the core-shell type composite abrasive model, and integrating the workpiece model and the core-shell type composite abrasive model; S3107: establishing a core-shell type composite abrasive polishing workpiece model.

[0013] In this technical solution, the area size is redefined, the core-shell composite abrasive model and the workpiece model are called, the workpiece model and the core-shell composite abrasive model are integrated together, and a core-shell composite abrasive impacting workpiece model is constructed to provide conditions for the subsequent simulation of the polishing process.

[0014] In any of the above technical solutions, the impact parameters of the abrasive particles are set to simulate the polishing process, specifically including: S4101: giving the core-shell composite abrasive particles a certain X-direction velocity v x ; S4102: Give the core-shell composite abrasive a certain Y direction speed v y ,in:

[0015] v y =ω(r+v x t) (1)

[0016] Where t is the polishing time, ω is the angular velocity of the polishing disk, and r is the eccentricity of the motion trajectory. The impact angle α of the core-shell composite abrasive at different times can be expressed as:

[0017]

[0018] The core-shell composite abrasive particles are made to perform non-linear motion to impact the workpiece at different impact angles; S4103: the degrees of freedom of the workpiece in the x-direction and the y-direction are fixed to limit its displacement in the x-direction and the y-direction.

[0019] In this technical solution, a certain initial velocity is given to the core-shell composite abrasive particles, so that the core-shell composite abrasive particles perform non-linear motion. By adjusting the X-direction velocity, the core-shell composite abrasive particle movement time, the polishing disk angular velocity, and the eccentricity and other parameters, the workpiece is impacted at different impact angles to simulate the process of polishing the workpiece with the core-shell composite abrasive particles.

[0020] In any of the above technical solutions, statistical analysis is carried out on the damage of the core-shell composite abrasive grains and the impact damage of the workpiece, specifically including: The analysis indexes of the core-shell composite abrasive grains are: crack propagation, interface damage condition and shell layer shedding condition. Observe the interface damage and shell layer shedding conditions of the core-shell composite abrasive grains at different moments when they impact the workpiece. Through the established discrete element model of the core-shell composite abrasive grains for polishing the workpiece, the crack propagation of the core-shell layer and the shell layer shedding condition are obtained, which is beneficial to a more comprehensive analysis of the reasons leading to the failure of the core-shell composite abrasive grains and to explore the stability of the core-shell composite abrasive grains. The evaluation indexes of the impact damage are: the number of cracks, the maximum crack depth and the average crack depth of the impacted part; By analyzing the damage degree of the workpiece, count the number of cracks on the surface and subsurface of the workpiece after impact, and analyze the main factors affecting the generation of the number of cracks during the polishing process; By analyzing the damage depth of the workpiece, count the maximum crack depth and the average crack depth of the workpiece, and analyze the main factors affecting the maximum crack depth and the average crack depth during the polishing process; According to the analysis of the damage degree and damage depth of the workpiece, the impact damage of the core-shell composite abrasive grains for polishing the workpiece is obtained.

[0021] This technical solution analyzes the simulation results. By observing the interface damage and shell layer shedding conditions, it analyzes the reasons leading to the failure of the core-shell composite abrasive grains and explores the stability of the core-shell composite abrasive grains. By detecting the number of cracks, the maximum crack depth and the average crack depth of the impacted part, the impact damage situation of the workpiece is obtained, and the influencing factors are analyzed, so as to improve the polishing effect of the workpiece.

[0022] The additional aspects and advantages of the present invention will become obvious in the following description part, or be understood through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a flow chart of the discrete element analysis method during the polishing process of the core-shell composite abrasive grains of the present invention.

[0024] Figure 2 It is a core-shell composite abrasive grain model of the present invention.

[0025] Figure 3 It is a workpiece model of the present invention.

[0026] Figure 4 It is a contact generation diagram of the bit composite abrasive grains of the present invention.

[0027] Figure 5 It is a discrete element model of the core-shell composite abrasive grains for polishing the workpiece of the present invention.

[0028] Figure 6 It is a diagram showing the impact angle of the core-shell composite abrasive grains of the present invention.

[0029] Figure 7This is the initial state of the discrete element simulation of polishing the workpiece with the core-shell composite abrasive of the present invention.

[0030] Figure 8 This is the state of the discrete element simulation of polishing the workpiece with the core-shell composite abrasive of the present invention at 60 s.

[0031] Figure 9 This is the state of the discrete element simulation of polishing the workpiece with the core-shell composite abrasive of the present invention at 180 s. Detailed implementation manners

[0032] In order to more clearly understand the above objects, features and advantages of the present invention, the present invention will be further described below in conjunction with the accompanying drawings and specific implementation manners. It should be noted that, without conflict, the embodiments of the present application and the features in the embodiments can be combined with each other.

[0033] Many specific details are set forth in the following description in order to fully understand the present invention. However, the present invention may be implemented in other ways different from those described herein. Therefore, the protection scope of the present invention is not limited by the specific embodiments disclosed below.

[0034] The following refers to Figures 1 to 9 Describe the model establishment and numerical simulation method of polishing the workpiece with the core-shell composite abrasive in some embodiments of the present invention.

[0035] In view of the fact that traditional inorganic abrasives cause "hard" impacts on the workpiece surface driven by the ultrasonic cavitation effect, which are prone to problems such as large scratches, cracks and pits. The present invention patent proposes a core-shell composite abrasive, which uses a polymer with better elasticity as the core and an inorganic material as the coating layer, effectively reducing the impact damage of the abrasive on the workpiece surface. The discrete element method is suitable for studying the situation at the micro scale and can better observe the damage of the core-shell composite abrasive and the impact damage of the workpiece during the polishing process.

[0036] In this embodiment, the workpiece to be polished is the workpiece, and the abrasive is the core-shell composite abrasive. By analyzing the damage of the core-shell composite abrasive and the impact damage of the workpiece by giving the core-shell composite abrasive a certain initial velocity, it can be applied to the scenario of workpiece polishing.

[0037] Example 1:

[0038] As Figure 1 shown, this embodiment provides a method for simulating the polishing process of the core-shell composite abrasive, including the following steps:

[0039] S1: Establish a workpiece model and assign parameters to the workpiece model;

[0040] S2: Establish a core-shell composite abrasive model and set the attributes and parameters of the core-shell composite abrasive model;

[0041] S3: Integrate the workpiece model and the core-shell composite abrasive model to establish a core-shell composite abrasive polishing workpiece model;

[0042] S4: Set the impact parameters of the core-shell composite abrasive and simulate the polishing process;

[0043] S5: Conduct statistical analysis on the damage of the core-shell composite abrasive and the impact damage of the workpiece.

[0044] This technical solution models the workpiece and the core-shell composite abrasive. By setting the attributes and parameters of the workpiece model and the core-shell composite abrasive model, the model achieves a better simulation effect.

[0045] In this embodiment, the discrete element simulation method is used to simulate the impact damage of the workpiece during the polishing process of the core-shell composite abrasive. Compared with the related finite element method, the discrete element method used in this embodiment can visualize the workpiece damage process during the polishing process, and can intuitively observe the situation of the workpiece impact damage during the polishing process. Compared with the manual experiment, the discrete element method in this embodiment has a fast calculation speed, simple setting, and saves time and effort.

[0046] Embodiment 2:

[0047] This embodiment provides a method for simulating the polishing process of core-shell composite abrasives. In addition to the technical features of the above embodiment, this embodiment further includes the following technical features:

[0048] Establish a workpiece model and set microscopic parameters for the workpiece model, which specifically includes the following steps:

[0049] S1101: Set the size of the first region and generate particles according to the first region;

[0050] S1102: Set the size of the first wall region;

[0051] S1103: Set the first radius, first porosity, first density, and first damping of the particles;

[0052] S1104: Appropriately enlarge the radius of the workpiece particles;

[0053] S1105: Adjust the radius of the floating particles with less than 3 contacts;

[0054] S1106: Set the first time of the generated particles and establish the workpiece model;

[0055] S1107: Model using the Bonded Particle Model (BPM). Generate parallel bonds between workpiece particles, set the parameters of the parallel bonds between workpiece particles, and add the first stiffness, the first normal-to-tangential stiffness ratio, the first friction coefficient, the first critical damping ratio, the first normal strength, the first cohesion, and the first friction angle to the workpiece model.

[0056] S1108: Set the bonding radius range between workpiece particles.

[0057] S1109: Delete the first wall to make the model in a relaxed state and obtain the BPM model of the workpiece.

[0058] This technical solution sets the generation of workpiece parameters, assigns parameters to the polished workpiece according to the actual situation, and performs modeling. In this specific embodiment, a rectangular workpiece is used as the impacted part, and the size of the impacted part is (80μm × 20μm), so as to make the model achieve a better simulation effect.

[0059] Example 3:

[0060] This embodiment provides a method for simulating the polishing process of core-shell composite abrasives. In addition to the technical features of the above embodiments, this embodiment further includes the following technical features:

[0061] Establish a core-shell composite abrasive model, which specifically includes the following steps:

[0062] S2101: Establish the shell model of the core-shell composite abrasive.

[0063] S2102: Set the size of the second region.

[0064] S2103: Set the size of the second wall region and generate shell particles in the second wall region.

[0065] S2104: Set the second radius, the second porosity, the second density, and the second damping of the shell particles.

[0066] S2105: Appropriately expand the radius of the shell particles.

[0067] S2106: Adjust the radius of the floating particles with less than 3 contacts.

[0068] S2107: Set the second time for generating the shell particles; establish the shell model of the core-shell composite abrasive.

[0069] S2108: Model using the particle bonding model and generate parallel bonds between the shell particles.

[0070] S2109: Set the parallel bond parameters between the shell particles, and add the second stiffness, the second normal-to-tangential stiffness ratio, the second friction coefficient, the second critical damping ratio, the second normal strength, the second cohesion, and the second friction angle to the core-shell composite abrasive shell model;

[0071] S2110: Set the range of the bonding radius between the shell particles;

[0072] S2110: Delete the second wall to make the model in a relaxed state, and obtain the corresponding BPM model;

[0073] S2112: Save the shell file of the core-shell composite abrasive;

[0074] S2201: Establish the core model of the core-shell composite abrasive;

[0075] S2202: Call the shell file of the core-shell composite abrasive;

[0076] S2203: Set the third radius, the third porosity, the third density, and the third damping of the core particles;

[0077] S2204: Set the size of the third region, and generate core particles according to the third region;

[0078] S2205: Appropriately expand the radius of the core particles;

[0079] S2206: Adjust the radius of the floating particles with less than 3 contacts;

[0080] S2207: Set the third time for generating the core particles, and establish the core model of the core-shell composite abrasive;

[0081] S2208: Use the particle bonding model for modeling to generate parallel bonds between the core particles;

[0082] S2209: Set the parallel bond parameters between the core particles, and add the third stiffness, the third normal-to-tangential stiffness ratio, the third friction coefficient, the third critical damping ratio, the third normal strength, the third cohesion, and the third friction angle to the core model;

[0083] S2210: Set the range of the bonding radius between the core particles;

[0084] S2211: Obtain the corresponding BPM model;

[0085] S2301: Set the interface layer contact parameters between the core and the shell of the core-shell composite abrasive model. For the bonding interface between the outer shell and the inner core of the core-shell composite abrasive, use the displacement softening contact model;

[0086] Contact strength F max is composed of the normal phase strength and tangential strength It is obtained by summation. Assuming that the contact strength changes linearly at a certain angle α, the contact strength F is obtained as follows: max Namely:

[0087]

[0088] When the combined contact force is greater than the contact strength (F > Fmax), the contact starts to deform. In each time step, the plastic displacement increment ΔUp is calculated as follows:

[0089]

[0090] In the formula: and respectively represent the normal and tangential plastic displacement increments. For the cumulative plastic displacement, we have:

[0091] Up = ∑|ΔUp| (3 - 3)

[0092] When the cumulative plastic displacement is greater than the maximum displacement (U p > U Pmax ), the contact load is broken.

[0093] S2401: Save the core - shell composite abrasive model.

[0094] In this technical solution, by setting the shell model of the core - shell composite abrasive and the shell model of the core - shell composite abrasive, the core abrasive grains and the shell abrasive grains are divided into two groups, and different attribute parameters are given to the shell layer, core layer of the composite abrasive grains and the interface between the core and the shell respectively to represent the model of the core - shell composite abrasive grains, providing a data basis and theoretical basis for subsequent simulation, and enhancing the authenticity and effectiveness of the simulation results.

[0095] The diameter of the core - shell composite abrasive grains is between 400 nm and 600 nm. In the specific embodiment created this time, the spherical core - shell composite abrasive grains have an inner core diameter of 500 nm and a shell thickness of 80 nm.

[0096] Example 4:

[0097] This embodiment provides a method for simulating the polishing process of core - shell composite abrasive grains. In addition to the technical features of the above - mentioned embodiments, this embodiment further includes the following technical features:

[0098] Integrate the workpiece model and the core - shell composite abrasive grain model to establish a core - shell composite abrasive grain polishing workpiece model, which specifically includes the following steps:

[0099] S3101: Delete the first region size and delete the second region size;

[0100] S3102: Establish the fourth region size;

[0101] S3103: Determine the coordinate position of the workpiece;

[0102] S3104: Call the workpiece model;

[0103] S3105: Determine the coordinate position of the core-shell composite abrasive grains;

[0104] S3106: Call the core-shell composite abrasive grain model and integrate the workpiece model and the core-shell composite abrasive grain model together;

[0105] S3107: Establish a core-shell composite abrasive grain polished workpiece model.

[0106] In this technical solution, the region size is redefined, the core-shell composite abrasive grain model and the workpiece model are called, and a core-shell composite abrasive grain impacting workpiece model is constructed, providing conditions for the subsequent simulation of the polishing process.

[0107] Example 5:

[0108] This embodiment provides a method for simulating the polishing process of core-shell composite abrasive grains. In addition to the technical features of the above embodiments, this embodiment further includes the following technical features:

[0109] Set the impact parameters of the abrasive grains and simulate the polishing process, specifically including the following steps:

[0110] S4101: Assign a certain X-direction velocity v to the core-shell composite abrasive grains x ;

[0111] S4102: Assign a certain Y-direction velocity v to the core-shell composite abrasive grains y , where:

[0112] v y = ω(r + v x t) (5-1)

[0113] In the formula, t is the polishing time, ω is the angular velocity of the polishing disc, and r is the motion eccentricity. Then, the impact angle α of the core-shell composite abrasive grains on the workpiece at different times can be expressed as:

[0114]

[0115] Make the core-shell composite abrasive grains move in a non-linear motion to achieve impacting the workpiece at different impact angles;

[0116] S4103: Fix the degrees of freedom of the workpiece in the x-direction and y-direction and restrict its displacement in the x-direction and y-direction.

[0117] In this technical solution, a certain initial velocity is imparted to the core-shell composite abrasive grains, causing the core-shell composite abrasive grains to move in a non-linear motion. By adjusting parameters such as the velocity magnitude in the X direction, the motion time of the core-shell composite abrasive grains, the angular velocity of the polishing disc, and the eccentricity, the process of simulating the polishing of the workpiece by the core-shell composite abrasive grains with different impact angles is realized.

[0118] Example 6:

[0119] This embodiment provides a method for simulating the polishing process of core-shell composite abrasive grains. In addition to the technical features of the above embodiments, this embodiment further includes the following technical features:

[0120] In any of the above technical solutions, statistical analysis is performed on the damage of the core-shell composite abrasive grains and the impact damage of the workpiece, which specifically includes the following steps:

[0121] The analysis indexes of the core-shell composite abrasive grains are: crack propagation, interface damage condition, and shell layer shedding condition. Observe the interface damage and shell layer shedding conditions of the core-shell composite abrasive grains at different moments when they impact the workpiece. Through the established discrete element model of the core-shell composite abrasive grains polishing the workpiece, the crack propagation of the core-shell layer and the shell layer shedding condition are obtained, which is beneficial to a more comprehensive analysis of the reasons leading to the failure of the core-shell composite abrasive grains and to explore the stability of the core-shell composite abrasive grains.

[0122] The evaluation indexes of the impact damage are: the number of cracks, the maximum crack depth, and the average crack depth of the impacted part; through the analysis of the damage degree of the workpiece, count the number of cracks on the surface and subsurface of the workpiece after impact, and analyze the main factors affecting the generation of the number of cracks during the polishing process; through the analysis of the damage depth of the workpiece, count the maximum crack depth and the average crack depth of the workpiece, and analyze the main factors affecting the maximum crack depth and the average crack depth during the polishing process; based on the analysis of the damage degree and damage depth of the workpiece, the impact damage of the core-shell composite abrasive grains polishing the workpiece is obtained.

[0123] This technical solution analyzes the simulation results. In this embodiment, observe the interface damage and shell layer shedding conditions of the core-shell composite abrasive grains when they impact the workpiece. Cracks first occur in the shell layer of the composite abrasive grains. As the cracks extend to the interface between the core layer and the shell layer, then the cracks continue to extend along the bonding interface. When the interface cracks extend to a certain extent, part of the shell layer sheds, resulting in the failure of the composite abrasive grains. In this embodiment, for the number of cracks inside the workpiece model, the counted number of cracks is 51,000, the maximum crack depth is 6.31 μm, and the average crack depth is 2.98 μm.

[0124] In summary, the beneficial effects of the present invention are:

[0125] 1. The invention uses core-shell composite abrasives to polish workpieces, establishes a "core-interface-shell" composite abrasive model, endows the mechanical properties of the interface of the core-shell composite abrasives, analyzes the constitutive relationship of the core / shell interface and the impact damage of the interface under impact

[0126] 2. The invention realizes the visualization of the damage of core-shell composite abrasives and the impact damage of workpieces during the polishing process, captures several model states for the process of polishing workpieces with composite abrasives, and can intuitively observe the damage of workpieces during the polishing process.

[0127] 3. Using the discrete element simulation method, the impact damage of workpieces during the polishing process of core-shell composite abrasives is simulated. Compared with the related finite element method, the discrete element method in this example can visualize the damage of workpieces during the polishing process and can intuitively observe the impact damage of workpieces during the polishing process. Compared with manual experiments, the discrete element method in this embodiment has a fast calculation speed, simple settings, and saves time and effort.

[0128] In the present invention, the terms "first", "second", "third" are only for the purpose of description and cannot be understood as indicating or implying importance; the directions indicated by the terms "x direction", "y direction", etc. are based on the directions shown in the drawings, which are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the present invention's limitation to the model is only in a specific direction. Therefore, it cannot be understood as a limitation to the present invention.

[0129] In the description of this specification, the description of terms such as "one embodiment" and "specific embodiment" means that the specific features described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features described can be combined in any one or more embodiments or examples in a suitable manner.

Claims

1. A method for simulating the polishing process of core-shell composite abrasive grains, characterized in that, Including: S1: Establish a workpiece model and assign parameters to the workpiece model. The specific steps are as follows: S1101: Set the size of the first region and generate particles according to the first region. S1102: Set the size of the first wall region. S1103: Set the first radius, first porosity, first density, and first damping of the particles. S1104: Appropriately enlarge the radius of the workpiece particles. S1105: Adjust the radius of the floating particles with a contact number less than 3. S1106: Set the first time for generating the particles and establish the workpiece model. S1107: Add a particle bonding model (Bonded Particle Model, BPM) to generate parallel bonds between the workpiece particles, set the parallel bond parameters between the workpiece particles, and add the first stiffness, first normal-to-tangential stiffness ratio, first friction coefficient, first critical damping ratio, first normal strength, first cohesion, and first friction angle to the workpiece model. S1108: Set the range of the bonding radius between the workpiece particles. S1109: Delete the first wall to make the model in a relaxed state and obtain the BPM model of the workpiece. S2: Establish a core-shell composite abrasive model and set the attributes and parameters of the core-shell composite abrasive model. The specific steps are as follows: S2101: Establish the shell model of the core-shell composite abrasive. S2102: Set the size of the second region. S2103: Set the size of the second wall region and generate shell particles in the second wall region. S2104: Set the second radius, second porosity, second density, and second damping of the shell particles. S2105: Appropriately enlarge the radius of the shell particles. S2106: Adjust the radius of the floating particles with a contact number less than 3. S2107: Set the second time for generating the shell particles and establish the shell model of the core-shell composite abrasive. S2108: Add a particle bonding model to generate parallel bonds between the shell particles. S2109: Set the parallel bond parameters between the shell particles, and add the second stiffness, second normal-to-tangential stiffness ratio, second friction coefficient, second critical damping ratio, second normal strength, second cohesion, and second friction angle to the core-shell composite abrasive shell model. S2110: Set the range of the bonding radius between the shell particles. S2111: Delete the second wall to make the model in a relaxed state and obtain the corresponding BPM model. S2112: Save the shell file of the core-shell composite abrasive. S2201: Establish the core model of the core-shell composite abrasive. S2202: Call the shell file of the core-shell composite abrasive. S2203: Set the third radius, third porosity, third density, and third damping of the core particles. S2204: Set the size of the third region and generate core particles according to the third region. S2205: Appropriately enlarge the radius of the core particles. S2206: Adjust the radius of the floating particles with a contact number less than 3. S2207: Set the third time for generating the core particles and establish the core model of the core-shell composite abrasive. S2208: Add a particle bonding model to generate parallel bonds between the core particles. S2209: Set the parallel bond parameters between the nuclear layer particles, and add the third stiffness, the third normal-to-tangential stiffness ratio, the third friction coefficient, the third critical damping ratio, the third normal strength, the third cohesion, and the third friction angle to the nuclear layer model; S2210: Set the range of the bonding radius between the nuclear layer particles; S2211: Obtain the corresponding BPM model; S2301: Set the interface layer contact parameters between the core and the shell of the core-shell composite abrasive model. For the bonding interface between the outer shell and the inner core of the core-shell composite abrasive, use the displacement softening contact model; S2401: Save the core-shell composite abrasive model; S3: Integrate the workpiece model and the core-shell composite abrasive model to establish a core-shell composite abrasive polishing workpiece model; The specific steps are as follows: S3101: Delete the size of the first region and delete the size of the second region; S3102: Establish the size of the fourth region; S3103: Determine the coordinate position of the workpiece; S3104: Call the workpiece model; S3105: Determine the coordinate position of the core-shell composite abrasive; S3106: Call the core-shell composite abrasive model and integrate the workpiece model and the core-shell composite abrasive model; S3107: Establish a core-shell composite abrasive polishing workpiece model; S4: Set the impact parameters of the core-shell composite abrasive and simulate the polishing process; S5: Conduct a statistical analysis of the damage of the core-shell composite abrasive and the impact damage of the workpiece.

2. The method for simulating the polishing process of a core-shell composite abrasive according to claim 1, wherein, Set the impact parameters of the abrasive and simulate the polishing process, specifically including: S4101: Impart a certain velocity v in the X direction to the core-shell composite abrasive grains x ; S4102: Impart a certain velocity v in the Y direction to the core-shell composite abrasive grains y , where: v y = ω(r + v x t) (1) In the formula, t is the polishing time, ω is the angular velocity of the polishing disc, and r is the eccentricity of the motion trajectory. Then, the impact angle α of the core-shell composite abrasive on the workpiece at different times is expressed as: Make the core-shell composite abrasive move in a non-linear motion to achieve impact on the workpiece at different impact angles; S4103: Fix the degrees of freedom of the workpiece in the x and y directions and restrict its displacement in the x and y directions.

3. A method for simulating the polishing process of core-shell composite abrasives according to claim 1, characterized in that, Conduct a statistical analysis of the damage of the core-shell composite abrasive and the impact damage of the workpiece, specifically including: The analysis indicators of the core-shell composite abrasive are: crack propagation, interface failure situation, and shell layer shedding situation. Observe the interface failure and shell layer shedding situations of the core-shell composite abrasive at different times when it impacts the workpiece. Through the established discrete element model of the core-shell composite abrasive polishing workpiece, the crack propagation and shell layer shedding situations of the core-shell layer are obtained, which is conducive to a more comprehensive analysis of the reasons leading to the failure of the core-shell composite abrasive and exploring the stability of the core-shell composite abrasive; The evaluation indicators of the impact damage are: the number of cracks, the maximum crack depth, and the average crack depth of the impacted part; Through the analysis of the damage degree of the workpiece, count the number of cracks on the surface and subsurface of the workpiece after impact, and analyze the main factors affecting the generation of the number of cracks during the polishing process; Through the analysis of the damage depth of the workpiece, count the maximum crack depth and the average crack depth of the workpiece, and analyze the main factors affecting the maximum crack depth and the average crack depth during the polishing process; According to the analysis of the damage degree and damage depth of the workpiece, the impact damage of the core-shell composite abrasive polishing workpiece is obtained.

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