阅读说明：本技术 碳纤维复合材料钻孔缺陷定量评价方法 (Quantitative evaluation method for drilling defects of carbon fiber composite material ) 是由 陈明 李超 徐锦泱 安庆龙 明伟伟 马海善 于 2019-11-13 设计创作，主要内容包括：一种碳纤维复合材料钻孔缺陷定量评价方法,通过引入撕裂缺陷、毛刺缺陷评价中的二维面积因子及基于颜色识别的缺陷面积计算技术,得到①三维分层因子即分层缺陷的体积占名义钻削体积的比值作为分层缺陷；②二维缺陷因子即缺陷面积占名义制孔面积的比值作为出口撕裂缺陷；③钻头出口处的表层的纤维拔出作为出口毛刺缺陷；经加权得到定量评价指标<Image he="70" wi="461" file="DDA0002271746230000011.GIF" imgContent="drawing" imgFormat="GIF" orientation="portrait" inline="no"></Image>当<Image he="58" wi="42" file="DDA0002271746230000012.GIF" imgContent="drawing" imgFormat="GIF" orientation="portrait" inline="no"></Image>为0.6～1时,则被测碳纤维复合材料即为缺陷产品。本发明克服现有的碳纤维复合材料钻孔加工质量评价标准中评价因素的缺失问题,提高定量评价结果的准确性。(A quantitative evaluation method for carbon fiber composite drilling defects comprises the steps of obtaining ① three-dimensional layering factors, namely the ratio of the volume of layering defects to the nominal drilling volume, as the layering defects, ② two-dimensional defect factors, namely the ratio of the defect area to the nominal drilling area, as the outlet tearing defects, pulling out fibers on the surface layer at the outlet of a ③ drill bit to serve as the outlet burr defects, and obtaining quantitative evaluation indexes through weighting by introducing two-dimensional area factors in the evaluation of the tearing defects and the burr defects and by using a defect area calculation technology based on color identification When in use When the carbon fiber composite material is 0.6-1, the detected carbon fiber composite material is a defective product. The invention overcomes the defect of evaluation factors in the existing evaluation standard of the drilling processing quality of the carbon fiber composite material and improves the accuracy of quantitative evaluation results.)

1. A quantitative evaluation method for drilling defects of carbon fiber composites is characterized in that ① three-dimensional layering factors, namely the ratio of the volume of layering defects to the nominal drilling volume, serve as layering defects, ② two-dimensional defect factors, namely the ratio of the defect area to the nominal drilling area, serve as outlet tearing defects, fibers on the surface layer of an outlet of a ③ drill bit are pulled out to serve as outlet burr defects, and quantitative evaluation indexes are obtained through weighting in a carbon fiber composite drilling process

2. The method according to claim 1, wherein the quantitative evaluation index is preferably a quantitative evaluation index

3. The method of claim 2, wherein the nominal area of the hole is calculated by calibrating the nominal hole diameter of the carbon fiber composite bore hole.

4. The method as claimed in claim 2, wherein the defect area is realized by color recognition, and the specific steps include:

①, scanning and detecting the processed carbon fiber composite material layer by using an ultrasonic scanning microscope to obtain layered images from the first layer to the last layer;

②, taking a picture of the outlet position of the processed carbon fiber composite material to obtain the image of the burr defect and the tearing defect at the outlet position;

③ the method comprises taking a square frame of unit area surrounding the hole making range, performing image recognition, pixelizing the picture, recognizing the color pixel area of the position corresponding to the defect, and comparing with the unit area to obtain two-dimensional ratio data of different defect factors.

Technical Field

The invention relates to a technology in the field of machining, in particular to a comprehensive defect evaluation method for three typical defects of carbon fiber composite materials, namely delamination, tearing and burrs, based on color area identification.

Background

The carbon fiber reinforced composite material is a material with high strength and light weight which is widely applied in aerospace equipment at present. Since the member connection is mainly performed by a connection method such as a bolt and a rivet, a large amount of hole processing is required. However, due to the property difference of the two-phase material of the carbon fiber composite material, the processing defect is very easy to generate during the pore-forming process, and the two-phase material is mainly classified into three types: delamination defects, exit tear defects, and exit burr defects. At present, the comprehensive influence of various defects is not considered in the detection and evaluation standard of the processing quality of the composite material, so that the processing capacity and the characteristics of a used hole making process and a used cutter cannot be accurately evaluated, and a quantitative evaluation index cannot be given, so that the fatigue strength and the service life of a composite material finished product cannot be predicted.

Disclosure of Invention

The invention provides a quantitative evaluation method for the drilling defects of carbon fiber composites, aiming at the defect that the existing defect detection means uses the ratio of the maximum diameter value of the range of the burr defects or the tearing defects to the nominal diameter of the drilled holes as an evaluation factor for evaluating the burr defects and the tearing defects in the composite drilling process to cause the deviation of the evaluation result.

The invention is realized by the following technical scheme:

the invention relates to a quantitative evaluation method for drilling defects of a carbon fiber composite material, which comprises the following steps of:

① taking the ratio of the volume of the three-dimensional delamination factor to the nominal drilling volume as the delamination defect;

② two-dimensional defect factor, namely the ratio of the defect area to the nominal hole making area is used as the outlet tearing defect;

③ drawing out the surface fiber at the outlet of the drill as outlet burr defect;

weighting to obtain quantitative evaluation indexWhen in use

When the carbon fiber composite material is 0.6-1, the detected carbon fiber composite material is a defective product, wherein: gamma ray_b、γ_tAnd gamma_dSequentially comprises a weight coefficient of burr defects, a weight coefficient of tearing defects and a weight coefficient of layered defects,

and F_vThe burr defect evaluation factor, the tearing defect evaluation factor and the three-dimensional layered defect evaluation factor are sequentially used.

The quantitative evaluation index is preferablyWherein: burr defect evaluation factorTear defect evaluation factor

Three-dimensional layered defect evaluation factorVolume of delamination defect in carbon fiber composite

Nominal volume V of carbon fiber composite material with delamination defect_nom＝p·h·A_nom，

Area of k-th layer where delamination defect occurs

Is the defective area of the ith burr, A_nomIs the nominal area of the hole.

The area of the ith tear.

And the nominal area of the hole is obtained by calibrating the nominal aperture of the carbon fiber composite material drilled hole and calculating.

The defect area is realized by adopting a color identification mode, and the specific steps comprise:

①, scanning and detecting the processed carbon fiber composite material layer by using an ultrasonic scanning microscope to obtain layered images from the first layer to the last layer;

②, taking a picture of the outlet position of the processed carbon fiber composite material to obtain the image of the burr defect and the tearing defect at the outlet position;

③ the method comprises taking a square frame of unit area surrounding the hole making range, performing image recognition, pixelizing the picture, recognizing the color pixel area of the position corresponding to the defect, and comparing with the unit area to obtain two-dimensional ratio data of different defect factors.

The pixelation is realized by using, but not limited to, Imagine J software.

Technical effects

Compared with the prior art, the method has the advantages that the hole making defects of the carbon fiber composite material are accurately and quantitatively evaluated; the method has the advantages that comprehensive defect evaluation of the drilling quality of the carbon fiber composite material plate from the layering defect, the tearing defect and the burr defect is realized, the inaccuracy of the conventional calculation method is overcome, the calculation efficiency is improved, the method can be closer to the actual situation of the hole making defect of the carbon fiber composite material plate, a more accurate means is provided for quantitative evaluation of the hole making defect, and the accurate prediction of the strength and the service life of a hole making workpiece made of the carbon fiber composite material is realized.

Drawings

FIG. 1 is a general schematic of the present invention;

FIG. 2 is a schematic diagram of a layered defect area and a nominal borehole area in an embodiment;

FIG. 3 is a schematic diagram illustrating a burr defect area processing process in an embodiment;

FIG. 4 is a schematic view of a tear defect area processing process in an embodiment.

Detailed Description

As shown in fig. 1, in the method for quantitatively evaluating the drilling quality of the carbon fiber composite material according to the embodiment, the drilling quality is quantitatively evaluated by introducing a delamination defect, an outlet tearing defect, and an outlet burr defect in the carbon fiber composite material drilling process.

The quantitative evaluation factor

Obtained by the following process:

as shown in fig. 2, the ultrasonic scanning is performed to identify the layering area in one layer of the processed carbon fiber composite material, and then the three-dimensional layering factor is calculated by the following formula:

V_nom＝p·h·A_nom，

as shown in fig. 3, firstly, image acquisition is performed on a drilling hole outlet, then image processing is performed, a square frame surrounding a unit area of a hole making range is taken, image recognition is performed on the square frame, pixelation is performed on the picture by using Imagine J software, the color pixel area of a position corresponding to a defect is recognized, and then comparison is performed with the unit area, so that two-dimensional proportion data of the burr defect is obtained.

As shown in fig. 4, the image of the tearing defect is processed, a square frame surrounding the unit area of the hole making range is taken for image recognition, the image is firstly pixilated by using Imagine J software, the color pixel area of the position corresponding to the defect is recognized, and then the color pixel area is compared with the unit area, so that the two-dimensional proportion data of the tearing defect is obtained.

The influence weights of the three defects on the hole making quality are analyzed and assigned.

Reuse formulaDetermining a quantitative evaluation factor

The foregoing embodiments may be modified in many different ways by those skilled in the art without departing from the spirit and scope of the invention, which is defined by the appended claims and all changes that come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.