A method for evaluating the porosity of composite materials based on ultrasonic testing

Abstract

The present invention relates to a method for evaluating the porosity of a composite material based on ultrasonic testing. The method comprises selecting a benchmark part and evaluating the part to be tested according to the benchmark part. The present invention proposes a method for evaluating the porosity of a composite material based on ultrasonic testing, which can effectively reduce the R&D cost and shorten the R&D cycle by implementing the method for evaluating the porosity of a composite material through the benchmark part.

Description

Technical Field

[0001] The invention relates to the technical field of ultrasonic detection of composite materials with complex structures, and in particular to a method for evaluating the porosity of composite materials based on ultrasonic detection. Background Art

[0002] Fiber reinforced composite materials have superior properties such as high strength, high hardness and low density, and are widely used in aerospace, military and other fields. Due to the manufacturing process limitations of composite materials, defects such as pores and delamination are easily formed during the manufacturing process. When these defects accumulate to a certain extent, the performance of the components will drop sharply. In order to control the quality of the finished composite materials, it is necessary to characterize the severity of the porosity. Therefore, effective detection of the porosity of composite materials is a necessary means to ensure the quality of composite parts.

[0003] At present, there are two main methods for testing the porosity of composite materials: destructive testing and non-destructive testing. Among them, Boeing, Airbus and other companies all use ultrasonic C-scan methods, based on comparison test blocks or ultrasonic attenuation evaluation curves to achieve porosity evaluation of structural parts. The biggest problem with this method is the preparation of porosity comparison test blocks, because the attenuation coefficients of composite materials with different material systems and porosities are different in the test, so comparison test blocks with different material systems, different thicknesses and different porosities are required. Porosity test blocks are generally obtained through a large number of anatomical screening and metallographic tests. The series of test blocks are time-consuming and costly, so it is generally necessary to carry out trial production of porosity test blocks during process finalization batch production. It is precisely because of the difficulty, time and cost of trial production of porosity test blocks that complex structural composite materials can only use metallographic testing and other destructive testing methods to one-sidedly count and evaluate porosity indicators during the research and development stage and small-batch trial production stage, which leads to continuous detours due to porosity problems during the research and development stage, which not only increases the process iteration cycle, but also increases the research and development cost.

[0004] At present, it is not very reasonable to use porosity test blocks to evaluate test pieces in the research and development stage and small-batch stage of complex structure composite materials. This type of method is only applicable to process finalization batch production. There is an urgent need for a new porosity detection and evaluation technical solution to support the complex structure composite materials in the research and development stage or small-batch trial production stage. Summary of the invention

[0005] In view of the above problems in the prior art, the present invention proposes a method for evaluating the porosity of composite materials based on ultrasonic detection, which can solve the problems of porosity detection and evaluation of complex structure composite materials in the research and development stage or small batch trial production stage, and can effectively reduce the research and development cost and shorten the research and development cycle.

[0006] Specifically, the present invention proposes a method for evaluating the porosity of a composite material based on ultrasonic detection, comprising the steps of:

[0007] S1. After the structural design of the complex composite material parts is completed, the corresponding strength calculation results are output, and the high stress areas are identified according to the strength calculation results. The designed parts are preliminarily partitioned in combination with the part structure to form a preliminary partition diagram;

[0008] S2. After the first batch of complex structure composite parts are trial-produced, ultrasonic penetration C scanning is carried out on the composite parts;

[0009] S3, combining the ultrasound penetration method C scanning result and the preliminary partition map to form a formal partition map;

[0010] S4. Performing regional statistics on the ultrasonic penetration C-scan results of the composite material parts according to the formal partition map;

[0011] S5, sorting the composite material parts according to the high stress area, and selecting the composite material parts with the highest attenuation and the second lowest attenuation;

[0012] S6, carrying out a strength test on the composite material part with the largest attenuation, if the strength test passes, the composite material part with the second largest attenuation is positioned as a benchmark part; if the strength test fails, returning to step S5;

[0013] S7, perform ultrasonic penetration C scanning on the parts to be inspected;

[0014] S8. Performing regional statistics on the ultrasonic penetration C scanning results of the parts to be inspected according to the formal partition map;

[0015] S9. Compare the parts to be inspected with the benchmark parts. If the ultrasonic attenuation value of the high stress area of ​​the parts to be inspected is greater than the ultrasonic attenuation value of the corresponding area of ​​the benchmark parts, the parts shall be rejected. If the ultrasonic attenuation of the high stress area of ​​the parts to be inspected is better than or equivalent to the ultrasonic attenuation value of the corresponding area of ​​the benchmark parts, then compare the ultrasonic attenuation values ​​of other areas. If the ultrasonic attenuation value of the parts to be inspected is worse than that of the benchmark parts, the parts shall be rejected.

[0016] According to an embodiment of the present invention, in step S5, the composite material parts are sorted according to the high stress areas. If the attenuation of the high stress areas is consistent, they are sorted according to the results of other partitions.

[0017] According to an embodiment of the present invention, in step S5, the composite material parts are sorted according to high stress areas, and the influence of system errors needs to be eliminated.

[0018] According to an embodiment of the present invention, in step S7, the detection parameters of the ultrasonic penetration method C-scan of the part to be inspected are the same as the detection parameters of the ultrasonic penetration method C-scan of the benchmark part.

[0019] The present invention provides a method for evaluating the porosity of a composite material based on ultrasonic testing. The method adopts a determined benchmark part and uses the benchmark part to implement the evaluation method for the porosity of the composite material, which can effectively reduce the R&D cost and shorten the R&D cycle.

[0020] It is to be understood that both the foregoing general description and the following detailed description of the present invention are exemplary and explanatory and are intended to provide further explanation of the invention as described. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The accompanying drawings are included to provide a further understanding of the present invention and are incorporated in and constitute a part of this application. The accompanying drawings illustrate embodiments of the present invention and together with the description serve to explain the principle of the present invention.

[0022] In the attached figure:

[0023] Figure 1 A flow chart of a method for evaluating the porosity of a composite material based on ultrasonic testing according to an embodiment of the present invention is shown.

[0024] Figure 2 The strength calculation cloud diagram of the first batch of complex structure composite parts is shown.

[0025] Figure 3 The first batch of C-scan images and corresponding partition diagrams of complex structure composite parts through penetration ultrasonic testing are shown. DETAILED DESCRIPTION

[0026] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application may be combined with each other.

[0027] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments. The following description of at least one exemplary embodiment is actually merely illustrative and is by no means intended to limit the present application and its application or use. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0028] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0029] Unless otherwise specifically stated, the relative arrangement, numerical expressions and numerical values ​​of the parts and steps set forth in these embodiments do not limit the scope of the present application. At the same time, it should be understood that, for ease of description, the sizes of the various parts shown in the accompanying drawings are not drawn according to the actual proportional relationship. The technology, method and equipment known to those of ordinary skill in the relevant field may not be discussed in detail, but in appropriate cases, the technology, method and equipment should be considered as a part of the authorization specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings, so that once a certain item is defined in an accompanying drawing, it does not need to be further discussed in subsequent drawings.

[0030] In the description of the present application, it should be understood that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the device or element referred to must have a specific direction or be constructed and operated in a specific direction, and therefore cannot be understood as limiting the scope of protection of the present application; the directional words "inside and outside" refer to the inside and outside relative to the contours of each component itself.

[0031] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used herein to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" may include both "above" and "below". The device may also be positioned in other different ways, rotated 90 degrees or in other orientations, and the spatially relative descriptions used herein are interpreted accordingly.

[0032] In addition, it should be noted that the use of words such as "first" and "second" to define components is only for the convenience of distinguishing the corresponding components. If not otherwise stated, the above words have no special meaning and cannot be understood as limiting the scope of protection of this application. In addition, although the terms used in this application are selected from well-known and commonly used terms, some terms mentioned in the specification of this application may be selected by the applicant at his or her discretion, and their detailed meanings are explained in the relevant parts of the description of this article. In addition, it is required to understand this application not only by the actual terms used, but also by the meaning implied by each term.

[0033] Figure 1 A flow chart of a composite material porosity evaluation method based on ultrasonic testing according to an embodiment of the present invention is shown. As shown in the figure, the present invention provides a composite material porosity evaluation method based on ultrasonic testing. The evaluation method comprises the following steps:

[0034] S1. After the structural design of complex composite parts is completed, the corresponding strength calculation results are output. Based on the strength calculation results, the high stress area is identified, and the designed parts are preliminarily partitioned in combination with the part structure to form a preliminary partition diagram.

[0035] S2. After the first batch of complex structure composite parts are trial-produced, ultrasonic penetration C scanning is carried out on the composite parts. Conventionally, each batch of complex structure composite parts is set at 12 pieces, and the molding process of this batch of parts should be consistent. The specific number can be adjusted according to the actual molding mold of the parts.

[0036] S3. Combining the ultrasonic penetration method C scanning result and the preliminary partition map generated in step S1, a formal partition map is formed.

[0037] S4. Perform regional statistics on the ultrasonic penetration C-scan results of composite parts according to the formal zoning map.

[0038] S5. Sort the composite parts according to the high stress areas, and select the composite parts with the highest attenuation and the second lowest attenuation.

[0039] S6. Perform a strength test on the composite material part with the largest attenuation. If the strength test passes, the composite material part with the second largest attenuation is used as the benchmark part; if the strength test fails, return to step S5.

[0040] S7. Perform ultrasonic penetration C scanning on the parts to be inspected.

[0041] S8. Perform regional statistics on the ultrasonic penetration C-scan results of the parts to be inspected according to the formal zoning diagram.

[0042] S9. Compare the parts to be inspected with the benchmark parts. If the ultrasonic attenuation value of the high stress area of ​​the parts to be inspected is greater than the ultrasonic attenuation value of the corresponding area of ​​the benchmark parts, the parts should be rejected. If the ultrasonic attenuation of the high stress area of ​​the parts to be inspected is better than or equivalent to the ultrasonic attenuation value of the corresponding area of ​​the benchmark parts, then compare the ultrasonic attenuation values ​​of other areas. If the ultrasonic attenuation value of the parts to be inspected is worse than that of the benchmark parts, the parts should be rejected.

[0043] The present invention provides a method for evaluating the porosity of composite materials based on ultrasonic testing, which mainly includes two parts. The first part is to determine the benchmark parts, including steps S1 to S6. The second part is to evaluate the parts to be tested by using the benchmark parts, including steps S7 to S9. The feature of the present invention is that the parts are divided into zones according to the strength and stress conditions of the parts, and the benchmark parts are selected from the first batch of complex structure composite parts according to the attenuation of ultrasonic testing. The other parts to be tested are subsequently subjected to ultrasonic testing and compared with the benchmark parts for acceptance.

[0044] Preferably, in step S5, the composite material parts are sorted according to the high stress areas. If the attenuation of the high stress areas is consistent, they are sorted according to the results of other partitions.

[0045] Preferably, in step S5, the composite material parts are sorted according to the high stress areas, and the influence of the system error needs to be eliminated.

[0046] Preferably, in step S7, the detection parameters of the ultrasonic penetration C scan of the part to be inspected are the same as those of the ultrasonic penetration C scan of the benchmark part, that is, the part to be inspected and the benchmark part are inspected at the same detection sensitivity.

[0047] Figure 2 The strength calculation cloud diagram of the first batch of complex structure composite parts is shown. Figure 3 The first batch of C-scan images and corresponding partition diagrams of penetration ultrasonic testing of composite parts with complex structures are shown. The following is a detailed description of a composite porosity evaluation method based on ultrasonic testing provided by the present invention in conjunction with the accompanying drawings.

[0048] refer to Figure 2 , use color blocks to distinguish low stress to high stress areas. Figure 2 The first batch of complex structure composite parts ultrasonic penetration method C-scan images and the corresponding preliminary partition map are divided into 4 areas, of which area 4 contains high stress areas, and the remaining areas are divided according to the difference in dB attenuation of the ultrasonic penetration method and the feasibility of the process. Combining the ultrasonic penetration method C-scan results and the preliminary partition map, a formal partition map is formed. According to the formal partition map, the ultrasonic penetration method C-scan results of composite parts are regionally counted, and the specific values ​​of ultrasonic attenuation in each partition of the first batch of 12 parts are given in Table 1.

[0049] Table 1 Attenuation of penetration ultrasonic testing in each test area

[0050]

[0051]

[0052] According to the high stress area, XXXX03 (with the highest attenuation) and XXXX06 (with the second lowest attenuation) were selected, and a strength test was conducted on XXXX03. After the test passed, XXXX06 with the second highest attenuation was determined as the benchmark part. When ultrasonic testing is performed on the parts to be tested later, the test sensitivity must be determined with the benchmark parts before batch testing. The penetration ultrasonic test results of each area of ​​the benchmark parts and batch parts are recorded according to Table 1.

[0053] Table 2 Attenuation of penetration ultrasonic testing in each test area

[0054]

[0055] As shown in Table 2, it includes benchmark parts and parts to be tested. If a 2dB system error is set, the error amount needs to be determined according to the actual condition of the equipment because the system error of each device is different. After comparison, the attenuation of the high stress area of ​​the part to be tested is consistent with that of the benchmark part, and then other areas are compared. It is found that the attenuation of area 3 of part XXXX15 is lower than that of the XXXX06 benchmark part. Therefore, XXXX15 is judged as unqualified and should be rejected.

[0056] The present invention provides an evaluation method for the porosity of composite materials based on ultrasonic testing, which indirectly counts the porosity trend of composite material parts in the form of benchmark parts, thereby avoiding spending a lot of time and cost on preparing porosity test blocks or one-sidedly counting and evaluating porosity indicators through destructive testing methods such as metallographic testing, thereby effectively solving the problems of process iteration cycle and increased R&D costs caused by porosity problems.

[0057] It will be apparent to those skilled in the art that various modifications and variations may be made to the above exemplary embodiments of the present invention without departing from the spirit and scope of the present invention. Therefore, it is intended that the present invention covers modifications and variations of the present invention that fall within the scope of the appended claims and their equivalent technical solutions.

Claims

1. A method for evaluating the porosity of a composite material based on ultrasonic detection, comprising the steps of: S1. After the structural design of the complex composite material parts is completed, the corresponding strength calculation results are output, and the high stress areas are identified according to the strength calculation results. The designed parts are preliminarily partitioned in combination with the part structure to form a preliminary partition diagram; S2. After the first batch of complex structure composite parts are trial-produced, ultrasonic penetration C scanning is carried out on the composite parts; S3, combining the ultrasound penetration method C scanning result and the preliminary partition map to form a formal partition map; S4. Performing regional statistics on the ultrasonic penetration C-scan results of the composite material parts according to the formal partition map; S5, sorting the composite material parts according to the high stress area, and selecting the composite material parts with the highest attenuation and the second lowest attenuation; S6, carrying out a strength test on the composite material part with the largest attenuation, if the strength test passes, the composite material part with the second largest attenuation is positioned as a benchmark part; if the strength test fails, returning to step S5; S7, perform ultrasonic penetration C scanning on the parts to be inspected; S8. Performing regional statistics on the ultrasonic penetration C scanning results of the parts to be inspected according to the formal partition map; S9. Compare the parts to be inspected with the benchmark parts. If the ultrasonic attenuation value of the high stress area of ​​the parts to be inspected is greater than the ultrasonic attenuation value of the corresponding area of ​​the benchmark parts, the parts shall be rejected. If the ultrasonic attenuation of the high stress area of ​​the parts to be inspected is better than or equivalent to the ultrasonic attenuation value of the corresponding area of ​​the benchmark parts, then compare the ultrasonic attenuation values ​​of other areas. If the ultrasonic attenuation value of the parts to be inspected is worse than that of the benchmark parts, the parts shall be rejected.

2. The evaluation method according to claim 1, wherein: In step S5, the composite material parts are sorted according to the high stress area. If the attenuation of the high stress area is consistent, they are sorted according to the results of other partitions.

3. The evaluation method according to claim 1, wherein: In step S5, the composite material parts are sorted according to the high stress areas, and the influence of system errors needs to be eliminated.

4. The evaluation method according to claim 1, wherein: In step S7, the detection parameters of the ultrasonic penetration C scan of the part to be inspected are the same as the detection parameters of the ultrasonic penetration C scan of the benchmark part.

Images