阅读说明：本技术 氢燃料电池汽车的碳纤维复合材料产品的裂纹维修方法 (Crack repair method for carbon fiber composite product of hydrogen fuel cell automobile ) 是由 代艳青 郝义国 于 2020-11-27 设计创作，主要内容包括：本发明涉及汽车复材产品修复技术领域,尤其涉及氢燃料电池汽车的碳纤维复合材料产品的裂纹维修方法,包括以下步骤：S1、根据碳纤维复合材料产品所产生的裂纹确定维修区域的范围,维修区域的形状根据产品上裂纹的实际分布形式而定,确定了维修区域的范围后,进行非维修区域的保护工作；S2、维修区域的表面打磨粗化及清洁；S3、修补之前的备料准备工作,包括裁剪碳纤维布和调配树脂两部分；S4、碳纤维补片修补；S5、补片加热固化；S6、维修区域后处理。本发明以创新的裂纹维修方法对碳纤维复合材料产品的裂纹区域进行修复,使其满足使用的强度要求,无需将产品整体更换,成本较低,解决了碳纤维复合材料汽车产品后期维修的问题。(The invention relates to the technical field of automobile composite product repair, in particular to a crack repair method of a carbon fiber composite product of a hydrogen fuel cell automobile, which comprises the following steps: s1, determining the range of a maintenance area according to cracks generated by the carbon fiber composite material product, determining the shape of the maintenance area according to the actual distribution form of the cracks on the product, and performing protection work of a non-maintenance area after determining the range of the maintenance area; s2, polishing, roughening and cleaning the surface of the maintenance area; s3, preparing materials before repairing, wherein the preparing work comprises cutting carbon fiber cloth and preparing resin; s4, repairing the carbon fiber patch; s5, heating and curing the patch; and S6, repairing the area and post-processing. The method repairs the crack area of the carbon fiber composite product by an innovative crack maintenance method, so that the crack area meets the use strength requirement, the product is not required to be integrally replaced, the cost is low, and the problem of later maintenance of the carbon fiber composite automobile product is solved.)

1. The crack repairing method of the carbon fiber composite material product of the hydrogen fuel cell automobile is characterized in that: the method comprises the following steps:

s1, determining the range of a maintenance area according to cracks generated by the carbon fiber composite material product, determining the shape of the maintenance area according to the actual distribution form of the cracks on the product, and performing protection work of a non-maintenance area after determining the range of the maintenance area, wherein the specific flow is as follows:

determining the minimum outline boundary where the crack is located, wherein the minimum outline boundary is the minimum outline boundary containing the crack when the crack is a single crack, and the minimum outline boundary is the minimum outline boundary containing all cracks in a concentrated area when the crack is the crack in the concentrated area and is in a regular shape;

after the minimum outline boundary is determined, amplifying the circle of the minimum outline boundary by Dmm, wherein D is more than or equal to 30mm, and obtaining a maintenance area;

after the maintenance area is determined, sticking and protecting the area outside the maintenance area on the carbon fiber composite material product by using a masking tape;

s2, grinding, roughening and cleaning the surface of the maintenance area, wherein the specific process comprises the following steps:

polishing and roughening the surface of the product in the maintenance area by using sand paper;

after polishing is finished, cleaning and wiping the polished area by using a cleaning agent;

s3, preparing materials before repairing, wherein the preparing work comprises cutting carbon fiber cloth and preparing resin;

wherein, the specific flow of cutting the carbon fiber cloth is as follows:

determining the number N of layers of the carbon fiber repairing patch, wherein the relation between the number N of layers and the wall thickness T1 of the crack area of the product and the single-layer thickness T2 of the carbon fiber cloth is as follows: n is T1 × 0.25/T2, and the calculation result of N adopts a principle of a further method to take an integer;

after the number N of the carbon fiber maintenance patches is determined, the shape and the size of each carbon fiber maintenance patch in a first carbon fiber maintenance patch N1 layer and a second carbon fiber maintenance patch N2 … layer N carbon fiber maintenance patch Nn layer are determined according to the shape and the size of a minimum outline boundary and a maintenance area, wherein the shape and the size of N1 are the same as those of the minimum outline boundary, the shape and the size of N2 are amplified by D/Nmm on the basis of the shape and the size of N1, the shape and the size of N3 are amplified by D/Nmm on the basis of the shape and the size of N2, and the like, the shape and the size of Nn are the same as those of the maintenance area;

after the shape and the size of each layer of carbon fiber repairing patch are determined, drawing the shape of each carbon fiber repairing patch on the carbon fiber cloth by using a drawing tool, cutting each piece of material by using scissors after drawing, and sorting and storing the pieces according to the sequence of use;

wherein, the concrete flow of blending resin is as follows:

the resin is A/B bi-component epoxy resin, and A, B components are mixed according to the mass ratio of 1:5 when the resin is prepared;

s4, repairing the carbon fiber patch, wherein the concrete flow is as follows;

brushing a layer of resin on the surface of a cleaned maintenance area of a product, wherein the resin is required to be uniform and not to flow on the surface of the product;

then attaching a first layer of carbon fiber maintenance patch N1 to a maintenance area, wherein N1 is overlapped with the center of the maintenance area, brushing a layer of resin on the surface of the first layer of carbon fiber maintenance patch N1, wherein the resin needs to fully and uniformly infiltrate the carbon fiber maintenance patch and cannot flow;

then, a second layer of carbon fiber maintenance patch N2 is pasted on the first layer of carbon fiber maintenance patch N1 in the same pasting mode, the centers of N2 and N1 are overlapped, a layer of resin is brushed on the surface of the second layer of carbon fiber maintenance patch N2, and the resin needs to fully and uniformly infiltrate the carbon fiber maintenance patch and cannot flow;

in the same way, until the Nn of the Nth layer of the carbon fiber repair patch is pasted, uniformly brushing a layer of resin on the surface of the Nn after the Nn is pasted, wherein the carbon fiber repair patch is required to be completely soaked by the resin and does not flow and hang;

finally, placing the repaired product in a dust-free normal-temperature environment for standing;

s5, heating and curing the patch, wherein the specific flow is as follows;

after the repaired product is stood at normal temperature to be surface-dried, a hot air gun is used for heating the region of the product with the patch to accelerate curing, and the heating is continuously carried out until the initial curing strength is reached;

s6, performing post-treatment on the maintenance area, wherein the specific flow is as follows:

heating and curing the patch area of the product, tearing off the masking tape adhered outside the maintenance area, then using abrasive paper to soak, and polishing the boss at the joint of the masking tape and the maintenance area until no boss exists; and wiping the maintained area clean after polishing.

2. The method for repairing cracks in a carbon fiber composite product for a hydrogen fuel cell vehicle according to claim 1, wherein: when the crack on the surface of the product penetrates the wall thickness of the product, after the range of the repair area on one side of the product is determined and the protection work for the non-repair area is performed by step S1, the range of the repair area on the other side of the product is determined again and the protection work for the non-repair area is performed by step S1.

3. The method for repairing cracks in a carbon fiber composite product for a hydrogen fuel cell vehicle according to claim 1, wherein: in step S2, when the surface of the product within the maintenance area is sanded and roughened by using sand paper, the transverse and longitudinal cross sanding is maintained to ensure that the sanding degree meets the requirement and the sanding depth needs to be kept consistent.

4. The method for repairing cracks in a carbon fiber composite product for a hydrogen fuel cell vehicle according to claim 1, wherein: in step S3, D/N is not less than 5 mm.

5. The method for repairing cracks in a carbon fiber composite product for a hydrogen fuel cell vehicle according to claim 1, wherein: in step S5, the heat gun was set at 100 ℃ at a distance of 150mm from the surface of the patch area.

6. The method for repairing cracks in a carbon fiber composite product for a hydrogen fuel cell vehicle according to any one of claims 1 to 5, wherein: and after the steps S1-S6 are finished, whether surface painting is carried out or not is determined according to the state of the original surface of the product and the position of the product in the vehicle body.

Technical Field

The invention relates to the technical field of repair of automobile composite products, in particular to a crack repair method for a carbon fiber composite product of a hydrogen fuel cell automobile.

Background

With the rise of new energy automobiles, the lightweight of automobiles is emphasized by various large host factories, and more lightweight materials are applied to automobile products. The carbon fiber composite material becomes a preferable material for light weight of automobiles due to a plurality of advantages of excellent high specific modulus, high specific strength, designability and the like, and more automobile manufacturers apply the carbon fiber composite material to automobile products so as to achieve the purpose of making automobiles lighter and safer.

However, due to the material characteristics of the carbon fiber composite material, the product made of the carbon fiber composite material has no plasticity, and does not have certain plasticity and ductility unlike the traditional sheet metal and plastic. Due to no plasticity, when the product of the carbon fiber composite material cracks due to accidents such as scratch and collision, the common maintenance mode can only replace damaged parts, and further, the later-stage use and maintenance cost of the automobile manufactured by the carbon fiber composite material is higher.

Disclosure of Invention

The invention aims to provide a crack maintenance method of a carbon fiber composite product of a hydrogen fuel cell automobile, aiming at the existing technical current situation, the product is not required to be integrally replaced, the cost is lower, and the problem of later maintenance of the carbon fiber composite automobile product is solved.

In order to achieve the purpose, the invention adopts the following technical scheme:

the crack repairing method for the carbon fiber composite material product of the hydrogen fuel cell automobile comprises the following steps:

s1, determining the range of a maintenance area according to cracks generated by the carbon fiber composite material product, determining the shape of the maintenance area according to the actual distribution form of the cracks on the product, and performing protection work of a non-maintenance area after determining the range of the maintenance area, wherein the specific flow is as follows:

determining the minimum outline boundary where the crack is located, wherein the minimum outline boundary is the minimum outline boundary containing the crack when the crack is a single crack, and the minimum outline boundary is the minimum outline boundary containing all cracks in a concentrated area when the crack is the crack in the concentrated area and is in a regular shape;

after the minimum outline boundary is determined, amplifying the circle of the minimum outline boundary by Dmm, wherein D is more than or equal to 30mm, and obtaining a maintenance area;

after the maintenance area is determined, sticking and protecting the area outside the maintenance area on the carbon fiber composite material product by using a masking tape;

s2, grinding, roughening and cleaning the surface of the maintenance area, wherein the specific process comprises the following steps:

polishing and roughening the surface of the product in the maintenance area by using sand paper;

after polishing is finished, cleaning and wiping the polished area by using a cleaning agent;

s3, preparing materials before repairing, wherein the preparing work comprises cutting carbon fiber cloth and preparing resin;

wherein, the specific flow of cutting the carbon fiber cloth is as follows:

determining the number N of layers of the carbon fiber repairing patch, wherein the relation between the number N of layers and the wall thickness T1 of the crack area of the product and the single-layer thickness T2 of the carbon fiber cloth is as follows: n is T1 × 0.25/T2, and the calculation result of N adopts a principle of a further method to take an integer;

after the number N of the carbon fiber maintenance patches is determined, the shape and the size of each carbon fiber maintenance patch in a first carbon fiber maintenance patch N1 layer and a second carbon fiber maintenance patch N2 … layer N carbon fiber maintenance patch Nn layer are determined according to the shape and the size of a minimum outline boundary and a maintenance area, wherein the shape and the size of N1 are the same as those of the minimum outline boundary, the shape and the size of N2 are amplified by D/Nmm on the basis of the shape and the size of N1, the shape and the size of N3 are amplified by D/Nmm on the basis of the shape and the size of N2, and the like, the shape and the size of Nn are the same as those of the maintenance area;

after the shape and the size of each layer of carbon fiber repairing patch are determined, drawing the shape of each carbon fiber repairing patch on the carbon fiber cloth by using a drawing tool, cutting each piece of material by using scissors after drawing, and sorting and storing the pieces according to the sequence of use;

wherein, the concrete flow of blending resin is as follows:

the resin is A/B bi-component epoxy resin, and A, B components are mixed according to the mass ratio of 1:5 when the resin is prepared;

s4, repairing the carbon fiber patch, wherein the concrete flow is as follows;

brushing a layer of resin on the surface of a cleaned maintenance area of a product, wherein the resin is required to be uniform and not to flow on the surface of the product;

then attaching a first layer of carbon fiber maintenance patch N1 to a maintenance area, wherein N1 is overlapped with the center of the maintenance area, brushing a layer of resin on the surface of the first layer of carbon fiber maintenance patch N1, wherein the resin needs to fully and uniformly infiltrate the carbon fiber maintenance patch and cannot flow;

then, a second layer of carbon fiber maintenance patch N2 is pasted on the first layer of carbon fiber maintenance patch N1 in the same pasting mode, the centers of N2 and N1 are overlapped, a layer of resin is brushed on the surface of the second layer of carbon fiber maintenance patch N2, and the resin needs to fully and uniformly infiltrate the carbon fiber maintenance patch and cannot flow;

in the same way, until the Nn of the Nth layer of the carbon fiber repair patch is pasted, uniformly brushing a layer of resin on the surface of the Nn after the Nn is pasted, wherein the carbon fiber repair patch is required to be completely soaked by the resin and does not flow and hang;

finally, placing the repaired product in a dust-free normal-temperature environment for standing;

s5, heating and curing the patch, wherein the specific flow is as follows;

after the repaired product is stood at normal temperature to be surface-dried, a hot air gun is used for heating the region of the product with the patch to accelerate curing, and the heating is continuously carried out until the initial curing strength is reached;

s6, performing post-treatment on the maintenance area, wherein the specific flow is as follows:

heating and curing the patch area of the product, tearing off the masking tape adhered outside the maintenance area, then using abrasive paper to soak, and polishing the boss at the joint of the masking tape and the maintenance area until no boss exists; and wiping the maintained area clean after polishing.

Further, when the crack on the surface of the product penetrates the wall thickness of the product, after the range of the repair area on one side of the product is determined and the protection work for the non-repair area is performed through step S1, the range of the repair area on the other side of the product is determined again through step S1 and the protection work for the non-repair area is performed.

Further, in step S2, when the surface of the product within the maintenance area is sanded and roughened by using sand paper, the transverse and longitudinal cross-lapping is maintained to ensure that the sanding degree meets the requirement, and the sanding depth needs to be kept consistent.

Further, in step S3, D/N is not less than 5 mm.

Further, in step S5, the heat gun is located 150mm from the surface of the patch area, and the temperature is set to 100 ℃.

Further, after the steps S1-S6 are completed, whether surface painting is performed is determined according to the state of the original surface of the product and the position of the product in the vehicle body.

The invention has the beneficial effects that:

the method repairs the crack area of the carbon fiber composite product by an innovative crack maintenance method, so that the crack area meets the use strength requirement, the product is not required to be integrally replaced, the cost is low, and the problem of later maintenance of the carbon fiber composite automobile product is solved.

Drawings

FIG. 1 is a flow chart of a crack repair method of the present invention;

FIG. 2 is a schematic diagram of the present invention for determining the scope of repair (the minimum contour boundary is square);

FIG. 3 is a schematic view of the present invention for determining the scope of service (the minimum contour boundary is a circle).

Detailed Description

The invention will be further explained with reference to the drawings.

Referring to fig. 1, a method for repairing cracks in a carbon fiber composite product of a hydrogen fuel cell vehicle, i.e., a vehicle component made of a carbon fiber composite material, includes the following steps:

s1, determining the range of a maintenance area according to cracks generated by the carbon fiber composite material product, determining the shape of the maintenance area according to the actual distribution form of the cracks on the product, and performing protection work of a non-maintenance area after determining the range of the maintenance area; s2, polishing, roughening and cleaning the surface of the maintenance area; s3, preparing materials before repairing, wherein the preparing work comprises cutting carbon fiber cloth and preparing resin; s4, repairing the carbon fiber patch; s5, heating and curing the patch; and S6, repairing the area and post-processing.

The specific process of step S1 is:

determining the minimum outline boundary where the crack is located, wherein the minimum outline boundary is the minimum outline boundary containing the crack when the crack is a single crack, and the minimum outline boundary is the minimum outline boundary containing all cracks in a concentrated area when the crack is the crack in the concentrated area and is in a regular shape; after the minimum outline boundary is determined, amplifying the circle of the minimum outline boundary by Dmm, wherein D is more than or equal to 30mm, and obtaining a maintenance area; and after the maintenance area is determined, sticking and protecting the area outside the maintenance area on the carbon fiber composite material product by using the masking tape.

Referring to fig. 2-3, the minimum contour boundary is a1 and the repair area is a 2. In fig. 2, the minimum contour boundary is a square, and the circumference of the minimum contour boundary is enlarged by 30mm to obtain a maintenance area; in fig. 3, the minimum contour boundary is a circle, and the circumference of the minimum contour boundary is enlarged by 40mm to obtain a repair area.

When the crack on the surface of the product penetrates the wall thickness of the product, after the range of the repair area on one side of the product is determined and the protection work for the non-repair area is performed by step S1, the range of the repair area on the other side of the product is determined again and the protection work for the non-repair area is performed by step S1.

When the crack on the surface of the product extends to the edge of the product, the edge of the product is taken as the boundary of the repair area.

The specific process of step S2 is:

polishing and roughening the surface of the product in the maintenance area by using sand paper, wherein the sand paper is 240 meshes; after polishing is completed, the polished area is cleaned and wiped by using a cleaning agent. When the sand paper is used for polishing and coarsening the surface of a product within a maintenance area, the horizontal and vertical cross polishing is kept to ensure that the polishing degree meets the requirement, and meanwhile, the polishing depth needs to be kept consistent, so that the phenomenon of unevenness caused by polishing in the same maintenance area is avoided.

In step S3, the specific procedure for cutting the carbon fiber cloth is as follows:

determining the number N of layers of the carbon fiber repairing patch, wherein the relation between the number N of layers and the wall thickness T1 of the crack area of the product and the single-layer thickness T2 of the carbon fiber cloth is as follows: n is T1 × 0.25/T2, and the calculation result of N adopts a principle of a further method to take an integer; after the number N of the carbon fiber maintenance patches is determined, the shape and the size of each carbon fiber maintenance patch in a first carbon fiber maintenance patch N1 layer and a second carbon fiber maintenance patch N2 … layer N carbon fiber maintenance patch Nn layer are determined according to the shape and the size of a minimum outline boundary and a maintenance area, wherein the shape and the size of N1 are the same as those of the minimum outline boundary, the shape and the size of N2 are amplified by D/Nmm on the basis of the shape and the size of N1, the shape and the size of N3 are amplified by D/Nmm on the basis of the shape and the size of N2, and the like, the shape and the size of Nn are the same as those of the maintenance area; after the shape and the size of each layer of carbon fiber maintenance patch are determined, the shape of each carbon fiber maintenance patch is drawn on the carbon fiber cloth by using drawing tools (such as a ruler, compasses, a marking pen and the like), and after the drawing is finished, each material sheet is cut by using scissors and is arranged and stored according to the use sequence.

Preferably, the D/N is not less than 5mm to ensure the appearance quality of the repaired product. If the actually calculated D/N is less than 5mm, the dimension D should be increased properly.

In step S3, the specific process of blending resin is as follows:

the resin adopts A/B bi-component epoxy resin which is a normal-temperature curing system, the curing degree can reach 60 percent after curing for 24 hours at normal temperature, and then related polishing and carrying treatment can be carried out.

When blending the resin, A, B components are blended and mixed according to the mass ratio of 1: 5. The total amount of resin used depends on the size of the repair area and the number of carbon fiber repair patches. The resin prepared in a single time needs to be used within 1 hour, if the time exceeds 1 hour, the resin needs to be prepared again for operation, and the resin needs to be slowly stirred in the process of preparing and stirring so as to avoid excessive bubbles generated in the stirring process.

The specific process of step S4 is:

brushing a layer of resin on the surface of a cleaned maintenance area of a product by using a 1-inch wooden handle brush or other brushes, wherein the resin is required to be uniform and not to flow on the surface of the product; then attaching a first layer of carbon fiber maintenance patch N1 to a maintenance area, wherein N1 is overlapped with the center of the maintenance area, brushing a layer of resin on the surface of the first layer of carbon fiber maintenance patch N1, wherein the resin needs to fully and uniformly infiltrate the carbon fiber maintenance patch and cannot flow; then, a second layer of carbon fiber maintenance patch N2 is pasted on the first layer of carbon fiber maintenance patch N1 in the same pasting mode, the centers of N2 and N1 are overlapped, a layer of resin is brushed on the surface of the second layer of carbon fiber maintenance patch N2, and the resin needs to fully and uniformly infiltrate the carbon fiber maintenance patch and cannot flow; in the same way, until the Nn of the Nth layer of the carbon fiber repair patch is pasted, uniformly brushing a layer of resin on the surface of the Nn after the Nn is pasted, wherein the carbon fiber repair patch is required to be completely soaked by the resin and does not flow and hang; and finally, placing the repaired product in a dust-free normal-temperature environment for standing for more than 4 hours.

The specific process of step S5 is:

and (3) after the repaired product is stood at normal temperature until the surface is dried, heating the region of the product with the patch by using a hot air gun to accelerate curing, and continuously heating to the initial curing strength. The distance between the hot air gun and the surface of the patch area is 150mm, the temperature is set to be 100 ℃, and the time for heating and curing is not less than 2 hours.

The specific process of step S6 is:

heating and curing the patch area of the product, tearing off the masking tape adhered outside the maintenance area, then soaking with abrasive paper, and polishing the boss at the joint of the masking tape and the maintenance area until no boss exists, wherein the abrasive paper is 400 meshes; and wiping the maintained area clean after polishing. During the polishing process, sufficient water needs to be ensured to infiltrate the sand paper and the polishing area so as to avoid influencing the apparent quality after polishing.

And after the steps S1-S6 are finished, whether surface painting is carried out or not is determined according to the state of the original surface of the product and the position of the product in the vehicle body. For covering parts or interior decoration parts of automobiles and the like, coating and painting are needed after repair, so that the colors of the covering parts or interior decoration parts are consistent with those of automobile bodies; for the carbon fiber part in the lower vehicle body or chassis area, coating and painting are not needed.

The method repairs the crack area of the carbon fiber composite product by an innovative crack maintenance method, so that the crack area meets the use strength requirement, the product is not required to be integrally replaced, the cost is low, and the problem of later maintenance of the carbon fiber composite automobile product is solved.

It should be understood that the above-mentioned embodiments are merely preferred embodiments of the present invention, and not intended to limit the scope of the invention, therefore, all equivalent changes in the principle of the present invention should be included in the protection scope of the present invention.