Simulation method of vibration assisted vacuum bag molding process of nanomodified resin

Abstract

The application provides a simulation method of vibration-assisted vacuum bag molding process of nano-modified resin, comprising the following steps: step 1, obtaining the mass ratio of DGEBA, MTHPA and DMP-30 in the nano-SiO2 modified resin; step 2, establishing the nano-SiO2 modified resin matrix in the Material Studio software according to the mass ratio; step 3, pre-relaxing the nano-SiO2 modified resin matrix; step 4, realizing the curing and crosslinking process of the pre-relaxed nano-SiO2 modified resin matrix based on the vibration-assisted vacuum bag molding process through a Perl script; and step 5, calculating the center-of-mass distance between different nano-SiO2 particles in the nano-SiO2 modified resin matrix after the curing and crosslinking process is completed. The application realizes the simulation of the vibration-assisted vacuum bag molding process of the nano-modified resin through the molecular dynamics method, and verifies the vibration effect of the process.

Description

Technical Field

[0001] This invention relates to a simulation method for vibration-assisted vacuum bag molding of nano-modified resin, belonging to the field of composite material simulation design technology. Background Technology

[0002] Resin materials, due to their excellent processability, chemical stability, and lightweight properties, have been widely used in composite matrix, electronic packaging materials, structural functional coatings, and many other fields. However, most resins (such as epoxy resins and unsaturated polyester resins) generally exhibit high brittleness after curing and cross-linking. Introducing nanomaterials into the resin matrix is ​​a common technical approach to improve their toughness. However, nanomaterials are susceptible to agglomeration due to factors such as interparticle forces, electrostatic forces, van der Waals forces, and external energy fields, leading to a deterioration in the overall performance of the modified resin. To address this, some researchers have proposed introducing a vibrational energy field and superimposing a vacuum process during the curing and molding of nano-modified resins, aiming to simultaneously reduce nanoparticle agglomeration and air bubbles within the system, thereby optimizing the modification effect. However, the scale of nanomaterials is on the nanometer scale, and traditional methods for simulating this process face two major bottlenecks: first, the simulation scale is insufficient to cover this scale, making it impossible to fully characterize the microscopic features of the system; second, even if the simulation scale is adequate, it is difficult to demonstrate the interaction forces between different molecules. These problems pose challenges to exploring the mechanism of this process. Summary of the Invention

[0003] The purpose of this invention is to provide a simulation method for vibration-assisted vacuum bag compression molding of nano-modified resins, so as to solve the problems existing in the prior art.

[0004] To address the aforementioned technical problems, this invention provides a simulation method for vibration-assisted vacuum bag molding of nano-modified resin, comprising: Step 1, obtaining the mass ratio of DGEBA, MTHPA, and DMP-30 in the nano-SiO2 modified resin; Step 2, establishing a nano-SiO2 modified resin matrix in Material Studio software based on the mass ratio obtained in Step 1; Step 3, pre-relaxing the nano-SiO2 modified resin matrix, wherein the pre-relaxation includes geometry optimization, NVT balancing, and NPT balancing; Step 4, implementing the curing and crosslinking process of the pre-relaxed nano-SiO2 modified resin matrix based on the vibration-assisted vacuum bag molding process using a Perl script; Step 5, calculating the centroid distance between different nano-SiO2 particles in the cured and crosslinked nano-SiO2 modified resin matrix to verify the vibration effect of the vibration-assisted vacuum bag molding process.

[0005] In one specific implementation, step 4 specifically comprises: Step 4.1 Marking the C atoms, O atoms, and vibrational atom sets participating in the reaction, and setting the corresponding crosslinking target and maximum reaction distance in the Perl script; Step 4.2 Determining whether the following conditions are met: the degree of crosslinking is less than the crosslinking target and the reaction distance is less than the maximum reaction distance. If both conditions are met, the corresponding C atoms and O atoms participating in the reaction are solidified and crosslinked to achieve molecular dynamics equilibrium; Step 4.3 After the crosslinking reaction is solidified, a vibrational energy field is applied to the vibrational atom set. After applying the vibrational energy field, an NPT equilibrium of one atmosphere is applied to simulate the vacuum bag pressing process, and the temperature is adjusted. Specifically, the temperature is increased when the temperature is <90℃ and kept at 90℃. Steps 4.2 to 4.3 are executed repeatedly until the degree of crosslinking is not less than the crosslinking target or the reaction distance is not less than the maximum reaction distance.

[0006] In one specific embodiment, the velocity v of the vibration energy field is calculated as: v = v0 + at, where v0 is the initial velocity, t is the time interval, and a is the acceleration, which is obtained from the vibration energy field of the actual nano-SiO2 modified resin produced by the vibration-assisted vacuum bag molding process.

[0007] In one specific embodiment, step 5 includes: calculating the centroid coordinates of each nano-SiO2 particle in the nano-SiO2 modified resin matrix, and calculating the centroid distance between different nano-SiO2 particles based on the centroid coordinates.

[0008] In one specific embodiment, the mass ratio of DGEBA, MTHPA, and DMP-30 in the nano-SiO2 modified resin is 251.25:200:1.

[0009] In one specific embodiment, the initial centroid distance between different nano-SiO2 particles in the nano-SiO2 modified resin matrix is ​​equal.

[0010] In one specific embodiment, the initial density of the nano-SiO2 modified resin matrix is ​​set to 0.8 g / cm³. 3 The force field used was COMPASSIII, and the density of the pre-relaxed nano-SiO2 modified resin matrix was 1.15725 g / cm³. 3 .

[0011] Compared with the prior art, the beneficial effects of the present invention are as follows.

[0012] This invention implements the curing and crosslinking process of pre-relaxed nano-SiO2 modified resin matrix based on vibration-assisted vacuum bag molding using Perl scripts. This allows for the simulation of the vibration-assisted vacuum bag molding process of nano-modified resin using molecular dynamics methods. By calculating the centroid distance between different nano-SiO2 particles in the cured and crosslinked modified resin matrix, this invention verifies the vibration effect of the vibration-assisted vacuum bag molding process and reveals the mechanism of vibration dispersion of nano-SiO2 particles, thereby exploring the effect of this process on nano-modified resin. Attached Figure Description

[0013] Figure 1 This is a flowchart illustrating the simulation method of the vibration-assisted vacuum bag compression molding process of the nano-modified resin of the present invention.

[0014] Figure 2 The flowchart of step 4 of this invention.

[0015] Figure 3 This is a schematic diagram of the nano-SiO2 modified resin matrix established in an embodiment of the present invention.

[0016] Figure 4 This is a schematic diagram of a nano-SiO2 modified resin matrix with labeled vibrational atom sets, according to an embodiment of the present invention.

[0017] Figure 5 This is a DSC curve of the nano-SiO2 modified resin matrix according to an embodiment of the present invention.

[0018] Figure 6 This is a collection of acceleration data obtained from the vibration energy field of nano-SiO2 modified resin produced by vibration-assisted vacuum bag molding process in this invention.

[0019] Figure 7 This is a crosslinking diagram of three nano-SiO2 particles at different reaction distances in an embodiment of the present invention (polymer molecular chains have been hidden). Detailed Implementation

[0020] The present invention will now be described in detail with reference to the embodiments and accompanying drawings. It should be noted that, unless otherwise specified, the embodiments and features described herein can be combined with each other.

[0021] refer to Figure 1A simulation method for vibration-assisted vacuum bag compression molding of nano-modified resin includes: Step 1, obtaining the mass ratio of DGEBA, MTHPA, and DMP-30 in the nano-SiO2 modified resin, specifically, the mass ratio of DGEBA, MTHPA, and DMP-30 in the nano-SiO2 modified resin is 251.25:200:1; Step 2, converting the mass ratio of DGEBA, MTHPA, and DMP-30 obtained in Step 1 into a molar ratio (including primary crosslinking products), and according to this molar ratio in Material... In Studio software, a nano-SiO2 modified resin matrix is ​​created; Step 3: The nano-SiO2 modified resin matrix is ​​pre-relaxed, including geometry optimization, NVT balancing, and NPT balancing; Step 4: The pre-relaxed nano-SiO2 modified resin matrix is ​​cured and cross-linked using a Perl script based on vibration-assisted vacuum bag molding; Step 5: The centroid distance between different nano-SiO2 particles in the cured and cross-linked modified resin matrix is ​​calculated to verify the effect of the vibration-assisted vacuum bag molding process. Specifically, Step 5 includes: using a Perl script to identify the coordinates of Si and O atoms in different nano-SiO2 particles, then calculating the centroid coordinates of the corresponding nano-SiO2 particles by combining the atomic mass and the corresponding atomic coordinates, and calculating the centroid distance d between different nano-SiO2 particles using the centroid coordinates of two nano-SiO2 particles. The formula for calculating the centroid distance d between different nano-SiO2 particles is: , where m 1i Represents the mass of the i-th atom in one of the nano-SiO2 particles, (x 1i y 1i , z 1i () represents the three-dimensional coordinates of the i-th atom in this nano-SiO2 particle. The coordinates of the centroid of this nano-SiO2 particle, m 2i Represents the mass of the i-th atom in another nano-SiO2 particle, (x 2i y 2i , z 2i () represents the three-dimensional coordinates of the i-th atom in this nano-SiO2 particle. The coordinates of the centroid of this nano-SiO2 particle represent the coordinates of the centroid.

[0022] refer to Figure 2Preferably, step 4 specifically comprises: Step 4.1 Marking the C atoms, O atoms, and vibrational atom sets participating in the reaction, and setting the corresponding crosslinking target and maximum reaction distance in the Perl script; Step 4.2 Determining whether the following conditions are met: crosslinking degree less than the crosslinking target & reaction distance less than the maximum reaction distance. If both conditions are met, the corresponding C atoms and O atoms participating in the reaction are solidified and crosslinked to achieve molecular dynamics equilibrium; Step 4.3 After the crosslinking reaction is solidified, a vibrational energy field is applied to the vibrational atom set. After applying the vibrational energy field, a vacuum bagging process is simulated through NPT equilibrium at one atmosphere. Then, the temperature is adjusted and the reaction distance is increased. Specifically, the temperature is increased when the temperature is less than 90°C and kept warm when the temperature is equal to 90°C. Steps 4.2 to 4.3 are executed repeatedly until the crosslinking degree is not less than the crosslinking target or the reaction distance is not less than the maximum reaction distance.

[0023] Preferably, the formula for calculating the velocity v of the vibration energy field is: v = v0 + at, where v0 is the initial velocity, t is the interval time, and a is the acceleration, which is obtained from the vibration energy field of the actual nano-SiO2 modified resin produced by the vibration-assisted vacuum bag molding process.

[0024] Preferably, the initial centroid distance between different nano-SiO2 particles in the nano-SiO2 modified resin matrix is ​​equal.

[0025] Specifically, the initial density of the nano-SiO2 modified resin matrix was set to 0.8 g / cm³. 3 The force field used was COMPASSIII, and the density of the pre-relaxed nano-SiO2 modified resin matrix was 1.15725 g / cm³. 3 .

[0026] The present invention will further demonstrate the detailed implementation process and technical effects of the simulation method of vibration-assisted vacuum bag compression molding of nano-modified resin through a specific embodiment, so as to facilitate understanding of the essence of the present invention.

[0027] experimental group

[0028] 1. Establishment of the nano-SiO2 modified resin matrix: a. Construct an empty box with dimensions of 80×80×60 mm and add three nano-SiO2 particles with a diameter of 20 Å. The three nano-SiO2 particles are labeled as nano-SiO2 particle No. 1, nano-SiO2 particle No. 2, and nano-SiO2 particle No. 3. Approximately 0.1% hydroxyl groups are grafted onto the surface of each nano-SiO2 particle to simulate the hydrophilicity of untreated nano-SiO2 particles. The grafting rate is calculated using the following formula: Where G represents the grafting rate, W f W represents the mass of the grafted nano-SiO2 particles. iThis represents the mass of the nano-SiO2 particles before grafting. The initial coordinates of the three nano-SiO2 particles were fixed at (60, 40, 30), (30, 22.68, 30), and (30, 27.32, 30), respectively, to ensure that the initial centroid distance between each different nano-SiO2 particle was equal. b. Filling the boxes: DGEBA, MTHPA, and DMP-30 were filled into each box at a mass ratio of 251.25:200:1 (this mass ratio was converted to a molar ratio (including the primary crosslinking product)), and the initial density was set to 0.8 g / cm³. 3 The force field was selected from COMPASSIII to establish the nano-SiO2 modified resin matrix. A schematic diagram of the nano-SiO2 modified resin matrix is ​​shown below. Figure 3 ;

[0029] 2. Pre-relaxation of the nano-SiO2 modified resin matrix: The nano-SiO2 modified resin matrix underwent 10,000 steps of geometry optimization, 100 ps of NVT equilibration, and 150 ps of NPT equilibration at 1 atmosphere. After pre-relaxation, the nano-SiO2 modified resin matrix was approximately 1.15725 g / cm³. 3 ;

[0030] 3. Simulate the curing and crosslinking process: Step a, set the initial reaction distance to 2.5 Å and the maximum reaction distance to 14 Å, and label the C atoms, O atoms, and vibrational atom sets participating in the reaction. Figure 4 In the figure, vibrational atom sets are marked. The yellow part in the nano-SiO2 modified resin matrix represents vibrational atom sets. To investigate the dispersion of nano-SiO2 particles in the early and middle stages of curing (90℃ for 15 min), according to... Figure 5 Test results, setting the crosslinking target to 35%; Step b, determine if the conditions are met: crosslinking degree less than the crosslinking target and reaction distance less than the maximum reaction distance. If the conditions are met, solidify the corresponding C and O atoms participating in the reaction to achieve molecular dynamics equilibrium; Step c, after solidifying the crosslinking reaction, apply a vibrational energy field to the vibrating atom set, and the velocity of the vibrational energy field is determined by... Figure 6 The test acceleration was calculated as shown. After applying the vibration energy field, one atmosphere of pressure was applied through NPT balance to simulate the vacuum bag pressing process. Then the temperature was adjusted. Specifically, the temperature was increased when the temperature was less than 90°C and kept at 90°C. After the above cycle was completed, steps b to c were continued until the degree of crosslinking was not less than the crosslinking target or the reaction distance was not less than the maximum reaction distance.

[0031] 4. Calculate the centroid distance between different nano-SiO2 particles to verify the vibration effect: Calculate the centroid distance between different nano-SiO2 particles inside the nano-modified resin matrix after achieving the cross-linking target.

[0032] control group

[0033] A nano-SiO2 modified resin matrix was established, the nano-SiO2 modified resin matrix was pre-relaxed, and the centroid distance between different nano-SiO2 particles was calculated. The vibration effect was verified to be the same as that of the experimental group.

[0034] The simulated curing and crosslinking process was as follows: Step a, the initial reaction distance was set to 2.5 Å, the maximum reaction distance to 14 Å, and the C and O atoms participating in the reaction were labeled. To investigate the dispersion of nano-SiO2 particles in the early and middle stages of curing (90℃ for 15 min), according to... Figure 5 The test results show that the crosslinking target is set at 35%. Step b involves determining whether the following conditions are met: the degree of crosslinking is less than the crosslinking target and the reaction distance is less than the maximum reaction distance. If the conditions are met, the corresponding C and O atoms involved in the reaction are solidified and crosslinked to achieve molecular dynamics equilibrium. Step c involves applying one atmosphere of pressure through NPT to simulate a vacuum bagging process, then adjusting the temperature and increasing the reaction distance. Specifically, the temperature is increased when the temperature is less than 90°C and kept at 90°C. Steps b to c are repeated until the degree of crosslinking is not less than the crosslinking target or the reaction distance is not less than the maximum reaction distance.

[0035] The centroid coordinates of each nano-SiO2 particle in the experimental group and the control group are shown in Table 1. The centroid distances between different nano-SiO2 particles in the experimental group and between different nano-SiO2 particles in the control group are shown in Table 2.

[0036] As shown in Table 2, after curing and crosslinking, the average centroid distance between different nano-SiO2 particles in the control group decreased from 33.36 Å to 31.71 Å, indicating that there was a tendency for different nano-SiO2 particles to agglomerate under vibration-free conditions. In the experimental group, the average centroid distance between different nano-SiO2 particles decreased by only 0.01 Å compared to the average centroid distance after relaxation (33.36 Å), while it increased by 1.64 Å compared to the control group. This indicates that the experimental group suppressed the agglomeration tendency between nano-SiO2 particles during the curing process and achieved effective simulation of vibration-dispersed nano-SiO2 particles.

[0037] Table 1: Centroid coordinates of nano-SiO2 particles

[0038]

[0039] Table 2: Centroid distance between different nano-SiO2 particles

[0040]

[0041] Figure 7The mechanism of vibration-dispersed nano-SiO2 particles was demonstrated. The distance at which cross-linking began to occur between three nano-SiO2 particles in the experimental group (with an applied vibrational energy field) (4.5 Å) was greater than that in the control group (without a vibrational energy field) (3.5 Å). This is because the polymer chains have a smaller mass compared to the nano-SiO2 particles, resulting in more intense relative motion under vibration and high temperature. The high mobility of the polymer chains allows them to migrate into the space between the nano-SiO2 particles, generating a steric hindrance effect, which in turn pushes the nano-SiO2 particles apart, thereby increasing the centroid distance between different nano-SiO2 particles.

[0042] In summary, this invention can effectively simulate the vibration-assisted vacuum bag molding process of nano-modified resin, verify the vibration effect of the vibration-assisted vacuum bag molding process, and reveal the mechanism of vibration dispersion of nano-SiO2 particles.

[0043] The above description, in conjunction with specific preferred embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various simple deductions and substitutions can be made without departing from the inventive concept, and all such modifications and substitutions should be considered within the scope of protection of the present invention.

Claims

1. A simulation method for vibration-assisted vacuum bag compression molding of nano-modified resin, characterized in that, include: Step 1: Obtain the mass ratio of DGEBA, MTHPA and DMP-30 in the nano-SiO2 modified resin; Step 2: Based on the mass ratio obtained in Step 1, construct a nano-SiO2 modified resin matrix in Material Studio software; Step 3: Pre-relax the nano-SiO2 modified resin matrix, the pre-relaxation including geometry optimization, NVT balancing and NPT balancing; Step 4: Implement the curing and crosslinking process of the pre-relaxed nano-SiO2 modified resin matrix based on vibration-assisted vacuum bag compression molding using a Perl script; Step 5: Calculate the centroid distance between different nano-SiO2 particles in the cured and cross-linked nano-SiO2 modified resin matrix to verify the vibration effect of the vibration-assisted vacuum bag compression molding process. Step 4 specifically involves: Step 4.1 Mark the C atoms, O atoms, and vibrational atom sets participating in the reaction, and set the corresponding crosslinking targets and maximum reaction distance in the Perl script; Step 4.2 Determine if the following conditions are met: the degree of crosslinking is less than the crosslinking target and the reaction distance is less than the maximum reaction distance. If both conditions are met, then the corresponding C and O atoms participating in the reaction are solidified and crosslinked to achieve molecular dynamics equilibrium. Step 4.3 After the curing and crosslinking reaction, a vibrational energy field is applied to the vibrational atom set. After applying the vibrational energy field, an NPT balance of one atmosphere is applied to simulate the vacuum bag pressing process, and the temperature is adjusted. Specifically, the temperature is increased when the temperature is <90℃ and kept at 90℃. Repeat steps 4.2 to 4.3 until the degree of crosslinking is not less than the crosslinking target or the reaction distance is not less than the maximum reaction distance.

2. The simulation method for vibration-assisted vacuum bag compression molding of nano-modified resin as described in claim 1, characterized in that, The velocity of the vibration energy field v The calculation formula is: v = v0 + at, where v0 is the initial velocity, t is the time interval, and a is the acceleration. The acceleration a is obtained from the vibration energy field of the actual nano-SiO2 modified resin produced by the vibration-assisted vacuum bag molding process.

3. The simulation method for vibration-assisted vacuum bag compression molding of nano-modified resin as described in claim 2, characterized in that, Step 5 includes: calculating the centroid coordinates of each nano-SiO2 particle in the nano-SiO2 modified resin matrix, and calculating the centroid distance between different nano-SiO2 particles based on the centroid coordinates.

4. The simulation method for vibration-assisted vacuum bag compression molding process of nano-modified resin as described in claim 3, characterized in that, The mass ratio of DGEBA, MTHPA, and DMP-30 in the nano-SiO2 modified resin is 251.25:200:

1.

5. The simulation method for vibration-assisted vacuum bag compression molding process of nano-modified resin as described in claim 4, characterized in that, The initial centroid distance between different nano-SiO2 particles in the nano-SiO2 modified resin matrix is ​​equal.

6. The simulation method for vibration-assisted vacuum bag compression molding process of nano-modified resin as described in claim 5, characterized in that, The initial density of the nano-SiO2 modified resin matrix was set to 0.8 g / cm³. 3 The force field used was COMPASSIII, and the density of the pre-relaxed nano-SiO2 modified resin matrix was 1.15725 g / cm³. 3 .

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