A Method for Establishing a Simulation Model of Ultrasonic-Assisted Grinding of Fiber Reinforced Composites Based on Multiscale Analysis

Abstract

The present invention discloses a method for establishing a simulation model of ultrasonic-assisted grinding of fiber-reinforced composites based on multi-scale analysis, which includes the following steps: First, a representative volume element at the microscopic scale of the composite material is established, and the mechanical properties of the representative volume element at the microscopic scale of the composite material, including the modulus and failure strength of the composite material, etc., are obtained through finite element analysis and assigned as the material properties of the fiber bundle. Then, the damage failure criterion of the fiber bundle is determined, and a mesoscopic scale simulation model of the fiber-reinforced composite material is established. Next, a corresponding grinding wheel model is established according to the required grinding wheel specifications, and finally, a mesoscopic scale simulation model of ultrasonic-assisted grinding of fiber-reinforced composites is established. The present invention is based on multi-scale model analysis, overcomes the problem of difficult modeling caused by the complex structure of the composite material, observes the processing process at multiple scales, and provides theoretical guidance for revealing the material removal mechanism of ultrasonic-assisted grinding of composites.

Description

Technical Field

[0001] The invention belongs to the field of composite material simulation processing, and specifically relates to a method for establishing a simulation model of fiber-reinforced composite material ultrasonic-assisted grinding processing based on multi-scale analysis. Background Art

[0002] The application of new energy and new materials has gradually become a hot topic with the development of industry. The demand for advanced composite materials in modern industry is increasing day by day. Composite materials such as resin-based fiber-reinforced composite materials and ceramic-based fiber-reinforced composite materials account for an increasing proportion of mechanical structures in the defense field. In this context, the study of the stiffness, strength and damage mechanism of fiber-reinforced composite materials has always been a hot and difficult issue in composite material research. Many scholars have analyzed the performance of composite materials from the aspects of simulation and experiment, but the exploration of the cutting and grinding mechanism of fiber-reinforced composite materials is not yet mature and still needs further exploration.

[0003] Ultrasonic assisted grinding is to integrate ultrasonic vibration system on traditional CNC machine tools, introduce high-frequency ultrasonic vibration in traditional grinding, change the mechanism of action between abrasive grains and workpieces, reduce grinding force, improve processing quality, and reduce grinding wheel wear. It has been proven to be suitable for the processing of hard and brittle materials. However, the ultrasonic assisted grinding test process is difficult to observe, and it cannot output intuitive parameters that reflect the changes in internal stress of the material.

[0004] Establishing a simulation model for ultrasonic-assisted grinding of fiber-reinforced composites and using finite element simulation to simulate the grinding process can effectively solve the above problems, which is of great significance for studying the damage behavior of fiber-reinforced composites and revealing the removal mechanism of fiber-reinforced composites. Today, scholars mostly use macroscopic models to study the damage behavior of fiber-reinforced composites. Macroscopic models have the ability to capture macroscopic or structural level damage, but they are usually insufficient in predicting microscopic damage inside the braided yarn and between the yarns, including fiber damage, fiber matrix debonding and matrix cracking, etc., while microscopic and mesoscopic models that can better observe microscopic damage have problems such as modeling difficulties and poor model accuracy. Summary of the invention

[0005] In view of the deficiencies in the prior art, the present invention proposes a method for establishing a simulation model for ultrasonic-assisted grinding of fiber-reinforced composite materials based on multi-scale analysis.

[0006] A method for establishing a simulation model of ultrasonic-assisted grinding of fiber-reinforced composite materials based on multi-scale analysis includes the following steps:

[0007] Step 1: Establish a micro-scale representative volume unit of fiber reinforced composite materials.

[0008] Step 2: Perform finite element analysis on the micro-scale representative volume element of the fiber-reinforced composite material to obtain the mechanical properties of the micro-scale representative volume element of the fiber-reinforced composite material, and assign them as the material properties of the fiber bundle.

[0009] Step 3: Establish a meso-scale simulation model of the fiber-reinforced composite material, including the braiding structure form and parameters, and the fiber volume fraction; determine the generation and failure criteria for matrix damage of the fiber bundle.

[0010] Step 4: According to the required grinding wheel specifications, use the grinding wheel rapid parametric modeling plug-in to generate a grinding wheel model with randomly distributed abrasive grains.

[0011] Step 5: Based on the above meso-scale simulation model of the fiber-reinforced composite material and the grinding wheel model, establish a meso-scale ultrasonic-assisted grinding processing simulation model of the fiber-reinforced composite material.

[0012] In establishing the micro-scale representative volume element of the fiber-reinforced composite material described in Step 1, it includes determining the unit cell type of the representative volume element, the model shape parameters, the generation and evolution criteria for matrix damage, the generation and evolution criteria for fiber material damage, the failure criteria for the interface, the boundary conditions, etc.

[0013] In the micro-scale representative volume element of the fiber-reinforced composite material described in Step 1, the unit cell types usually include two types: the regular hexahedron unit cell model and the regular hexagonal prism unit cell model. The advantage of the regular hexagonal prism model compared to the regular hexahedron model is that it maintains the transverse isotropy characteristics under the random distribution condition, while the latter shows obvious transverse anisotropy under the uniform distribution assumption.

[0014] In the micro-scale representative volume element of the fiber-reinforced composite material described in Step 1, when determining the failure criteria of the matrix, since the matrix material is usually considered a homogeneous isotropic material, the failure criteria can be selected as the maximum principal stress criterion, the maximum stress criterion, the maximum strain criterion, the Von-Mises criterion, etc.

[0015] In the micro-scale representative volume element of the fiber-reinforced composite material described in Step 1, when determining the failure criteria of the fibers, different types of fibers have different applicable failure criteria. Isotropic fibers such as quartz fibers are applicable to the maximum principal stress criterion, the maximum stress criterion, the maximum strain criterion, the Von-Mises criterion, etc., and transversely isotropic fibers such as carbon fibers are applicable to the Hoffman criterion, the Tsai-Wu criterion, the maximum stress criterion, etc.

[0016] In the micro-scale representative volume element of the fiber-reinforced composite material described in Step 1, for the progressive damage of the matrix material and the fiber material, it is necessary to analyze the generation and evolution criteria for damage under different failure modes (tensile failure, compressive failure, shear failure, etc.) in order to modify the stiffness matrix of the damaged material.

[0017] In the finite element analysis described in Step 2, it refers to applying boundary conditions to the representative volume element at the microscale of the fiber-reinforced composite material until it fails, and calculating the mechanical properties of the material through the obtained stress-strain curve, including tensile strength, shear strength, compressive strength, etc. in different directions.

[0018] In the fiber bundle failure criterion described in Step 3, first, determine the structure of the material at the mesoscale according to the weaving pattern of the material, so as to determine its failure criterion, such as the Hashin criterion, the Puck criterion, etc. Then, regard the fiber bundle as an equivalent homogeneous object and endow it with mechanical properties such as the failure strength parameters obtained in Step 2.

[0019] In the grinding wheel modeling described in Step 4, it includes the process of creating abrasive grains with multiple different shapes and particle sizes, creating the grinding wheel matrix, and randomly distributing the abrasive grains.

[0020] In the mesoscale fiber-reinforced composite material ultrasonic-assisted grinding processing simulation model described in Step 5, the contact type between the units in the contact part of the grinding wheel and the workpiece is surface-to-surface contact, and the friction between the workpiece and the grinding wheel can be processed by means such as penalty function.

[0021] A method for establishing a mesoscale fiber-reinforced composite material ultrasonic-assisted grinding processing simulation model based on multi-scale analysis provided by the present invention has the following advantages:

[0022] First, as a grinding processing simulation model, it can solve problems such as the high cost of fiber-reinforced composite materials and the difficulty in observing the grinding process. Although the commonly used macroscopic models today have the ability to capture macroscopic or structural-level damage, they are usually insufficient in predicting microscopic damage occurring inside and between woven yarns, including fiber damage, fiber-matrix debonding, and matrix cracking. The multi-scale modeling idea provided by the present invention realizes information transmission between different scales through a reasonable homogenization method. This type of method can effectively predict stress, strain, stiffness, damage, and various state variables at multiple scales, overcomes the problem of difficult modeling caused by the complex structure of fiber-reinforced composite materials, and provides theoretical guidance for revealing the material removal mechanism of ultrasonic-assisted grinding of fiber-reinforced composite materials. Brief Description of the Drawings

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0024] Figure 1Flowchart of the method for establishing an ultrasonic-assisted grinding processing simulation model of fiber-reinforced composites based on multi-scale analysis provided by the present invention.

[0025] Figure 2 Schematic diagram of the ultrasonic-assisted grinding processing simulation model of fiber-reinforced composites based on multi-scale provided by the present invention. Specific embodiments

[0026] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0027] As Figure 1 shown, the embodiments of the present invention disclose a method for establishing an ultrasonic-assisted grinding processing simulation model of fiber-reinforced composites based on multi-scale analysis. The experimental method process includes the following steps:

[0028] Step 1: As Figure 2 shown, establish a representative volume element at the microscale of fiber-reinforced composites. The unit cell type of the representative volume element is selected as a regular hexahedron unit cell model. The failure criterion of the fiber is selected as the maximum principal stress criterion, the failure criterion of the matrix is selected as the maximum principal stress criterion, the failure criterion of the interface is selected as the maximum stress criterion, and the constitutive model of the interface is selected as the cohesive model.

[0029] Step 2: Apply periodic boundary conditions to the representative volume element for finite element analysis, process the analysis results, obtain the tensile strength, tensile modulus, compressive strength, compressive elastic modulus, shear strength, etc. of the material, and assign the above mechanical properties as the material properties of the fiber bundle.

[0030] Step 3: As Figure 2 shown, establish a mesoscale simulation model of fiber-reinforced composites. The failure criterion of the matrix is selected as the maximum principal stress criterion, and the fiber bundle is regarded as an equivalent homogeneous object, and its failure criterion is selected as the Tsai-Wu failure criterion.

[0031] Step 4: As Figure 2 shown, use a rapid parametric modeling plugin for the grinding wheel to generate a grinding wheel model with randomly distributed abrasive grains. The grinding wheel selects a resin-bonded diamond grinding wheel with a grit size of 80#. First, create multiple abrasive grains with different shapes and different particle sizes, make their particle sizes follow a normal distribution, then create the grinding wheel matrix, and finally make the abrasive grains randomly distributed on the outer surface of the grinding wheel matrix.

[0032] Step 5: AsFigure 2 As shown, based on the above mesoscale simulation model of fiber-reinforced composites and the grinding wheel model, a mesoscale simulation model of ultrasonic-assisted grinding of fiber-reinforced composites is established.

[0033] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, rather than limiting it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for establishing a simulation model of ultrasonic-assisted grinding of fiber-reinforced composite materials based on multi-scale analysis, characterized in that It includes the following steps: Step 1: Establish a representative volume element (RVE) of the fiber-reinforced composite material at the microscale; Step 2: Conduct a finite element analysis on the RVE of the fiber-reinforced composite material at the microscale, obtain the mechanical properties of the RVE of the fiber-reinforced composite material, and assign them as the material properties of the fiber bundle; Step 3: Establish a mesoscale simulation model of the fiber-reinforced composite material, including the weaving structure form and parameters, and the fiber volume fraction; determine the generation and failure criteria for matrix damage of the fiber bundle; Step 4: According to the required grinding wheel specifications, use a grinding wheel rapid parametric modeling plug-in to generate a grinding wheel model with randomly distributed abrasive grains; Step 5: Based on the above mesoscale simulation model of the fiber-reinforced composite material and the grinding wheel model, establish a mesoscale simulation model for ultrasonic-assisted grinding of the fiber-reinforced composite material.

2. The ultrasonic-assisted grinding process simulation model of fiber-reinforced composite materials based on multi-scale analysis according to claim 1, characterized in that: In establishing the RVE of the fiber-reinforced composite material described in Step 1, it includes determining the unit cell type of the RVE, the model shape parameters, the generation and evolution criteria for matrix material damage, the generation and evolution criteria for fiber material damage, the failure criteria for the interface, and the boundary conditions.

3. The ultrasonic-assisted grinding process simulation model of fiber-reinforced composite materials based on multi-scale analysis according to claim 1, wherein: In the RVE of the fiber-reinforced composite material described in Step 1, the unit cell types include a regular hexahedron unit cell model and a regular hexagonal prism unit cell model.

4. The ultrasonic-assisted grinding process simulation model of fiber-reinforced composite materials based on multi-scale analysis according to claim 1, wherein: In the RVE of the fiber-reinforced composite material described in Step 1, when determining the failure criteria of the matrix, since the matrix material is usually considered a homogeneous isotropic material, the selected failure criteria include: the maximum principal stress criterion, the maximum stress criterion, the maximum strain criterion, and the Von-Mises criterion.

5. The ultrasonic-assisted grinding process simulation model of fiber-reinforced composite materials based on multi-scale analysis according to claim 1, characterized in that: In the RVE of the fiber-reinforced composite material described in Step 1, when determining the failure criteria of the fiber, different failure criteria apply to fibers with different properties. The maximum principal stress criterion, the maximum stress criterion, the maximum strain criterion, and the Von-Mises criterion apply to isotropic fibers, and the Hoffman criterion, the Tsai-Wu criterion, and the maximum stress criterion apply to transversely isotropic fibers.

6. The ultrasonic-assisted grinding process simulation model of fiber-reinforced composite materials based on multi-scale analysis according to claim 1, characterized in that: In the RVE of the fiber-reinforced composite material described in Step 1, the progressive damage of the matrix material and the fiber material needs to analyze the generation and evolution criteria for damage under different failure modes, so as to correct the stiffness matrix of the damaged material. The failure modes include tensile failure, compressive failure, and shear failure.

7. The ultrasonic-assisted grinding process simulation model of fiber-reinforced composite materials based on multi-scale analysis according to claim 1, characterized in that: In Step 2, the finite element analysis refers to applying boundary conditions to the RVE of the fiber-reinforced composite material at the microscale until it fails, and calculating the mechanical properties of the material through the obtained stress-strain curve, including the tensile strength, shear strength, and compressive strength in different directions.

8. The ultrasonic-assisted grinding process simulation model of fiber-reinforced composite materials based on multi-scale analysis according to claim 1, characterized in that: In the fiber bundle failure criterion described in Step 3, first determine the structure of the material at the mesoscale according to the weaving method of the material, so as to determine its failure criterion, including the Hashin criterion and the Puck criterion, and then regard the fiber bundle as an equivalent homogeneous object and assign the failure strength parameters obtained in Step 2 with mechanical properties.

9. The ultrasonic-assisted grinding process simulation model of fiber-reinforced composite materials based on multi-scale analysis according to claim 1, characterized in that: In the grinding wheel modeling described in Step 4, it includes the process of creating multiple abrasive grains with different shapes and particle sizes, creating a grinding wheel matrix, and randomly distributing the abrasive grains.

10. The ultrasonic-assisted grinding process simulation model of fiber-reinforced composite materials based on multi-scale analysis according to claim 1, characterized in that: In the mesoscopic scale fiber-reinforced composite material ultrasonic-assisted grinding simulation model described in Step Five, the contact type between the units in the contact part of the grinding wheel and the workpiece is surface-to-surface contact, and the friction treatment method between the workpiece and the grinding wheel includes using the penalty function.

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