Embedded body and layered reference block for nondestructive testing of composite material

Abstract

The utility model discloses an insert for nondestructive testing of a composite material and a layered reference block. The insert for nondestructive testing of the composite material comprises a first sub-insert with a first diameter and a second sub-insert with a second diameter, a second sub-insert having a second diameter smaller than the first diameter; the two first sub-embedded bodies are oppositely arranged, and the edges of the two first sub-embedded bodies are fixedly connected, so that a closed air enrichment body is formed between the two first sub-embedded bodies; the second sub-embedded body is located between the two first sub-embedded bodies, and the second sub-embedded body is fixedly connected with one of the first sub-embedded bodies. According to the embedded body for the nondestructive testing of the composite material, the stable embedded body for the nondestructive testing of the composite material can be formed, resin can be prevented from being immersed into the embedded body in the curing process, and gas in the embedded body can be prevented from being immersed into the resin to form natural defects in the pressed process.

Description

Technical Field

[0001] This utility model belongs to the field of nondestructive testing technology for composite materials, specifically relating to an insert and a layered comparison test block for nondestructive testing of composite materials. Background Technology

[0002] Non-destructive testing (NDT) delamination comparison blocks are test blocks pre-placed within composite material parts to simulate delamination defects. These blocks are used for equipment calibration and defect identification comparison during internal quality inspection of composite material parts. The quality of the NDT delamination comparison block largely determines the outcome of the internal quality assessment of the composite material part. Therefore, manufacturing high-quality delamination comparison blocks is crucial for determining the internal quality of composite materials.

[0003] The traditional method for manufacturing delamination comparison test blocks involves pre-laying a double-layer PTFE film inside the composite material part, using the air layer formed between the two PTFE films to simulate delamination defects. However, due to differences in resin flowability, the quality of the delamination comparison test blocks manufactured using this method is not stable. If the resin has good flowability, it can easily penetrate between the two PTFE films during curing, resulting in indistinct echoes and failing to form the expected delamination defects. Furthermore, under pressure, the gas between the two PTFE films can easily penetrate the surrounding resin, forming natural defects around the pre-existing defects. Utility Model Content

[0004] To address the shortcomings of existing technologies, this utility model provides an insert for non-destructive testing of composite materials and a layered comparison test block, which can form a stable insert for non-destructive testing of composite materials. This can prevent resin from seeping into the insert during the curing process and also prevent gas in the insert from seeping into the resin during the pressure process, thus preventing natural defects.

[0005] To achieve the above objectives, the technical solution adopted by this utility model is as follows:

[0006] In a first aspect, an insert for nondestructive testing of composite materials is provided, comprising: a first sub-insert having a first diameter; a second sub-insert having a second diameter smaller than the first diameter; two first sub-inserts disposed opposite to each other, and the edges of the two first sub-inserts being fixedly connected, thereby forming a sealed air-rich mass between the two first sub-inserts; the second sub-insert being located between the two first sub-inserts, and the second sub-insert being fixedly connected to one of the first sub-inserts.

[0007] Furthermore, the axis of the second sub-embedded body coincides with the axis of the first sub-embedded body.

[0008] Furthermore, the total thickness of the second sub-embedded body and the two first sub-embedded bodies is less than or equal to 0.1 mm.

[0009] Furthermore, both the second sub-embedded body and the first sub-embedded body are made of adhesive release fabric.

[0010] In a second aspect, a method for preparing a layered comparison test block for nondestructive testing of composite materials is provided, comprising: preparing an insert, wherein the insert is the nondestructive testing insert for composite materials described in the first aspect; hot-pressing the insert; and embedding the hot-pressed insert into a composite material layup to form a layered comparison test block for nondestructive testing of composite materials.

[0011] Further, the preparation of the insert includes: bonding the second sub-insertion to one of the first sub-insertions with adhesive; setting the two first sub-insertions opposite to each other and bonding the edges of the two first sub-insertions together with adhesive, and placing the second sub-insertion between the two first sub-insertions, thereby obtaining the insert.

[0012] Furthermore, the insert is subjected to hot pressing treatment, including: arranging auxiliary materials according to the auxiliary material arrangement requirements during the curing of the composite material nondestructive testing layered comparison test block; and hot-pressing the insert according to the curing system requirements of the composite material nondestructive testing layered comparison test block to expel excess gas inside the insert to avoid the formation of natural defects during final curing and to compress the thickness of the insert as much as possible.

[0013] Further, embedding the hot-pressed insert into the composite material layup includes: laying a first layup; performing a first vacuum hot compaction after the first layup is laid; after the first vacuum hot compaction, placing the hot-pressed insert at a predetermined position on the first layup and wrapping a twist strip around the insert; then performing a second vacuum hot compaction on the assembly formed by the first layup, the insert, and the twist strip; after the second vacuum hot compaction, laying a second layup on top of the insert and performing a third vacuum hot compaction; after the third vacuum hot compaction, arranging auxiliary materials according to the requirements for making a layered comparison test block for non-destructive testing of composite materials and curing it, thereby embedding the hot-pressed insert into the composite material layup.

[0014] Thirdly, a layered comparison test block for nondestructive testing of composite materials is provided, wherein the layered comparison test block is prepared by the preparation method of the layered comparison test block for nondestructive testing of composite materials described in the second aspect.

[0015] Furthermore, the layered comparison test block for nondestructive testing of composite materials includes: an insert, a first ply located below the insert, a second ply located above the insert, and a twist strip wound around the insert.

[0016] Compared with the prior art, the beneficial effects achieved by this utility model are as follows: This utility model provides a first sub-embedded body with a first diameter; a second sub-embedded body with a second diameter smaller than the first diameter; two first sub-embedded bodies are arranged opposite each other and their edges are fixedly connected, thereby forming a sealed air-rich mass between the two first sub-embedded bodies; the second sub-embedded body is located between the two first sub-embedded bodies and is fixedly connected to one of the first sub-embedded bodies, which can form a stable non-destructive testing embedding for composite materials. This can prevent resin from impregnating into the embedding body during the curing process and also prevent gas in the embedding body from impregnating into the resin during the pressure process, thus preventing natural defects. Attached Figure Description

[0017] Figure 1 This is a schematic diagram showing the relative positional relationship between the first sub-embedded body and the second sub-embedded body in an embedding for non-destructive testing of composite materials provided in this embodiment of the present invention;

[0018] Figure 2 This is a schematic diagram of the structure of a layered comparison test block for nondestructive testing of composite materials provided in this embodiment of the present invention;

[0019] In the diagram: 1. First ply; 2. Inlay; 21. First sub-inlay; 22. Second sub-inlay; 3. Twist strip; 4. Second ply. Detailed Implementation

[0020] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention.

[0021] Example 1

[0022] like Figure 1 As shown, an insert for nondestructive testing of composite materials includes: a first sub-insertion 21 having a first diameter; a second sub-insertion 22 having a second diameter smaller than the first diameter; two first sub-insertions 21 are disposed opposite to each other and their edges are fixedly connected, thereby forming a sealed air-rich mass between the two first sub-insertions 21; the second sub-insertion 22 is located between the two first sub-insertions 21 and is fixedly connected to one of the first sub-insertions 21.

[0023] This invention takes the fabrication of a composite material non-destructive testing insert with a diameter of 6mm as an example to further illustrate the structure and fabrication method of the composite material non-destructive testing insert described in this invention.

[0024] In this utility model, both the first sub-embedded body 21 and the second sub-embedded body 22 are made of adhesive release cloth.

[0025] The method for fabricating an insert for nondestructive testing of composite materials includes: bonding the adhesive surface of a 4mm diameter adhesive release cloth (second sub-insert 22) to the adhesive surface of a 6mm diameter adhesive release cloth (first sub-insert 21), with the 4mm diameter adhesive release cloth centered on the 6mm diameter adhesive release cloth (i.e., keeping the axis of the second sub-insert 22 coincident with the axis of the first sub-insert 21); then bonding the non-adhesive surface of another 6mm diameter adhesive release cloth to the aforementioned 6mm diameter adhesive release cloth, with the edges of the two 6mm diameter adhesive release cloths overlapping. A sealed air-rich mass is formed by wrapping a 4mm diameter adhesive release cloth with the two 6mm diameter adhesive release cloths. This completes the fabrication of the insert for nondestructive testing of composite materials.

[0026] This invention enables the fabrication of composite material non-destructive testing inserts with a total thickness of less than or equal to 0.1 mm for the second sub-insert 22 and the two first sub-inserts 21. In this invention, the first sub-inserts 21 and the second sub-inserts 22 can also be made of other single-sided adhesive materials as needed.

[0027] Example 2

[0028] Based on the composite material nondestructive testing insert described in Example 1, this example provides a method for preparing a layered comparison test block for composite material nondestructive testing. The method includes: preparing an insert 2; hot-pressing the insert 2; and embedding the hot-pressed insert 2 into the composite material layup to form a layered comparison test block for composite material nondestructive testing.

[0029] (1) Preparation of insert 2: First, the second sub-insert 22 is glued to one of the first sub-inserts 21; then, the two first sub-inserts 21 are arranged opposite each other and their edges are glued together, with the second sub-insert 22 located between the two first sub-inserts 21, thereby obtaining insert 2. Specifically, the method of making inserts for non-destructive testing of composite materials in Example 1 can be used to make insert 2.

[0030] (2) Hot pressing treatment of the insert 2: Move the insert 2 into the glass platform and arrange the auxiliary materials according to the auxiliary material arrangement requirements when the composite material non-destructive testing layered comparison test block is cured; hot press the insert 2 according to the curing system requirements of the composite material non-destructive testing layered comparison test block to expel excess gas inside the insert 2 to avoid the formation of natural defects during final curing and to compress the thickness of the insert 2 as much as possible.

[0031] (3) Embedding the hot-pressed insert 2 into the composite material layup: Laying the first layup 1 (the first layup 1 is the layup located below the insert 2), after the first layup 1 is laid, a first vacuum hot compaction is performed. The purpose of this hot compaction step is to remove air trapped between the prepreg layers at the placement position of the insert 2; after the first vacuum hot compaction, the hot-pressed insert 2 is placed at the designated position of the first layup 1, and a twist strip 3 is wrapped around the insert 2. Then, a second vacuum hot compaction is performed on the assembly formed by the first layup 1, the insert 2 and the twist strip 3. The purpose is to eliminate air entrapment between the insert 2 and the first layup 1 and reduce the fiber bridging problem caused by the step difference of the insert; after the second vacuum hot compaction, the second layup 4 is laid on top of the insert 2, and a third vacuum hot compaction is performed to ensure that the second layup 4 and the insert 2 are completely bonded; after the third vacuum hot compaction, auxiliary materials are arranged and cured according to the requirements for the fabrication of a layered comparison test block for non-destructive testing of composite materials, thereby embedding the hot-pressed insert 2 into the composite material layup, and forming a layered comparison test block for non-destructive testing of composite materials through curing and other processes, such as... Figure 2 As shown.

[0032] This invention uses hot compaction to expel excess gas from the insert, preventing it from seeping into the surrounding prepreg and causing natural defects during final curing. At the same time, hot compaction compresses the insert thickness as much as possible to prevent bridging defects caused by the step difference of the insert when the upper prepreg is laid.

[0033] This invention effectively removes excess gas from the prepreg to avoid the formation of natural defects by hot-compacting the prepreg before and after placement and after the prepreg is laid on the upper part of the prepreg. At the same time, twisted strips made of single yarn are wrapped around the defects to reduce the natural defects of fiber bridging in the upper part caused by the step difference of the prepreg.

[0034] This invention can effectively solve the problems of unclear echoes, inability to form the expected delamination defects, and the formation of natural defects around pre-embedded defects in traditional autoclave delamination defect simulation comparison test blocks. It greatly improves the manufacturing quality of non-destructive testing delamination comparison test blocks, brings convenience to product testing, and improves the product's pass rate.

[0035] Example 3

[0036] Based on the composite material nondestructive testing insert described in Example 1 and the preparation method of the composite material nondestructive testing layered comparison test block described in Example 2, this example provides a composite material nondestructive testing layered comparison test block. The layered comparison test block is provided with the composite material nondestructive testing insert described in Example 1 and is manufactured using the preparation method of the composite material nondestructive testing layered comparison test block described in Example 2. It includes: an insert 2, a first layup 1 located below the insert 2, a second layup 4 located above the insert 2, and a twist strip 3 wound around the insert 2. Figure 2 As shown.

[0037] The above description is only a preferred embodiment of the present utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present utility model, and these improvements and modifications should also be considered within the protection scope of the present utility model.

Claims

1. An insert for nondestructive testing of composite materials, characterized in that, include: A first sub-embedded body (21) having a first diameter; A second sub-embedded body (22) having a second diameter smaller than the first diameter; Two first sub-embedded bodies (21) are arranged opposite to each other, and the edges of the two first sub-embedded bodies (21) are fixedly connected, thereby forming a sealed air-rich mass between the two first sub-embedded bodies (21); the second sub-embedded body (22) is located between the two first sub-embedded bodies (21), and the second sub-embedded body (22) is fixedly connected to one of the first sub-embedded bodies (21).

2. The composite material nondestructive testing insert according to claim 1, characterized in that, The axis of the second sub-embedded body (22) coincides with the axis of the first sub-embedded body (21).

3. The composite material nondestructive testing insert according to claim 1, characterized in that, The total thickness of the second sub-embedded body (22) and the two first sub-embedded bodies (21) is less than or equal to 0.1 mm.

4. The insert for nondestructive testing of composite materials according to claim 1, characterized in that, The second sub-embedded body (22) and the first sub-embedded body (21) are both made of adhesive release fabric.

5. A layered comparison test block for nondestructive testing of composite materials, characterized in that, The layered comparison test block includes a hot-pressed insert, which is the non-destructive testing insert for composite materials as described in any one of claims 1 to 4.

6. The composite material nondestructive testing layered comparison test block according to claim 5, characterized in that, Also includes: The first ply (1) located below the insert (2), the second ply (4) located above the insert (2), and the twist strip (3) wrapped around the insert (2).

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