JP3506868B2 - Artificial defect material of fiber reinforced resin composite material and method for producing the same - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an aircraft, an automobile,
The present invention relates to an artificial defect material used in nondestructive inspection of a fiber reinforced resin composite material used as a material for ships or general industrial equipment and a manufacturing method thereof, and particularly, to a fiber reinforced resin composite material effective in ultrasonic flaw detection. An artificial defect material and a manufacturing method thereof.

[0002]

2. Description of the Related Art In recent years, the application of fiber-reinforced resin composite materials has been expanding in all industries, and there is a high demand for reliability in its strength. Against this background, nondestructive inspection of composite material parts is important. Is. A non-destructive inspection requires a standard defect test piece in which an artificial defect material is inserted, and in particular, the standard defect test piece is indispensable in ultrasonic flaw detection.

The most excellent artificial defect material in the ultrasonic flaw detection method is air (or gas or vacuum space), and this air blocks 100% of ultrasonic permeability.
It is known to have the property of reflecting 100% of the reflectivity.

Conventionally, as a method for producing this standard defect test piece, as disclosed in, for example, Japanese Patent Laid-Open No. 61-265565, a columnar material is cut out from a once molded part, and delamination is performed on this columnar material. After forming the, again to return to the cut out holes to adhere to the method of manufacturing a standard defect test piece,
As shown in the document “Yasai Nondestructive Inspection Technology” (1996, Industrial Research Board, Publishing Company, 7.4 composite material), a polytetrafluoroethylene film was used as an artificial defect material, and this film was used. A method is known in which a prepreg is inserted between laminated materials to form a standard defect test piece.

[0005]

The method of producing a standard defect test piece by cutting a cylindrical material from a molded part requires a great deal of labor and time for production, and the shape of the artificial defect is limited to a circular shape. Further, in the case of a thin-walled molded part, there is a problem that it is difficult to return the holes to the holes and bond them after forming delamination on the cut columnar material.

The manufacturing method using a polytetrafluoroethylene film as an artificial defect material utilizes the non-adhesiveness and releasability of the polytetrafluoroethylene film. By releasing with a mold, an extremely thin release layer is created, and this release layer works effectively in the ultrasonic flaw detection method of nondestructive inspection, the transmission method blocks the transmission of ultrasonic waves, and the reflection method efficiently transmits ultrasonic waves. It has the property of reflecting,
When this film is used as an artificial defect material, the film sometimes stays in close contact with the composite material without releasing it, and does not function as an artificial defect material at all, or peels off only partially, resulting in defects. There is a problem that the size is unclear and inaccurate, and the reliability and stability of inspection are low.

The present invention has been made in view of the present situation, and as a characteristic of the material itself, it has a high attenuation ability and a high reflection ability with respect to ultrasonic waves, and can cause a difference in transmittance even in an X-ray inspection method. It is an object of the present invention to provide an artificial defect material of a fiber-reinforced resin composite material that can be manufactured and is easy to manufacture, and a manufacturing method thereof.

[0008]

The artificial defect material of the fiber reinforced resin composite material of the present invention is constituted by containing glass micro hollow spheres in a sheet, and the gas existing inside the glass micro hollow spheres is ultrasonic wave. Demonstrate excellent characteristics against.

The artificial defect material of the fiber-reinforced resin composite material of the present invention can obtain high flexibility and workability by forming the sheet from silicon rubber. Although the ultrasonic characteristics of this silicone rubber are not at the air level, they have superior characteristics compared to conventional polytetrafluoroethylene sheets.

The artificial defect material of the fiber-reinforced resin composite material of the present invention has a glass micro hollow sphere diameter of 30 to 150 μm,
By setting the thickness of the sheet to 0.1 to 0.3 mm, a few glass micro hollow spheres are dispersed in the thickness direction of the sheet, whereby the characteristics against ultrasonic waves are further improved. By setting the content of the glass micro hollow spheres to 30 to 60%, it becomes possible to obtain high ultrasonic characteristics in the entire area of the sheet.

In the method for producing an artificial defect material of a fiber-reinforced resin composite material of the present invention, glass micro hollow spheres are uniformly dispersed in a two-liquid mixed curing type silicone rubber before curing, and this is removed in a vacuum container. It is characterized in that it is cured as a sheet of a predetermined thickness while foaming, and glass micro hollow spheres can be easily and uniformly dispersed in the sheet.

The method for producing an artificial defect material of a fiber-reinforced resin composite material of the present invention is to uniformly disperse glass micro hollow spheres in a silicone rubber before curing of a two-liquid mixing curing type, and remove this in a vacuum container. After foaming, place it on a smooth plate, place a heavy object with a smooth bottom on it, insert a spacer of a predetermined thickness between the plate and the heavy object, and further while defoaming in a vacuum container. It is characterized in that it is cured to form a sheet having a predetermined thickness, and glass micro hollow spheres can be easily and uniformly dispersed in the sheet.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an artificial defect material of a fiber-reinforced resin composite material according to an embodiment of the present invention,
The artificial defect material 1 is composed of glass micro hollow spheres 3 dispersed in a silicon rubber bonding base material 2. The glass micro hollow sphere 3 has a sphere diameter of about 30 to 150 μm,
The thickness T of the bonding base material (sheet) 2 is set to about 0.1 to 0.3 mm. Preferably, the artificial defect material 1 has a content of the glass micro hollow spheres 3 in the bonding substrate 2 of 30 to 60%.
Then, a few glass micro hollow spheres 3 are dispersed and arranged in the thickness T direction of the artificial defect material 1.

This artificial defect material 1 is cut with a cutter or the like in accordance with a required artificial defect size, laminated on a laminated material of prepreg and cured, and used as a standard defect test piece in a nondestructive inspection of a fiber reinforced resin composite material. Used.

Next, a method of manufacturing the artificial defect material 1 will be described.

First, a glass micro hollow sphere 3 having a sphere diameter of about 30 to 150 μm is prepared, and the glass micro hollow sphere 3 is a two-component mixed curing type uncured silicone rubber in which a curing agent is mixed with a main agent to cure the glass micro hollow sphere 3. It is added to the solution so that the content rate is about 30 to 60%, and stirred to uniformly disperse the glass micro hollow spheres 3 in the silicone rubber solution. As the glass micro hollow spheres 3, a trade name “Glass Micro Balloon” manufactured by Nippon Silica Industry Co., Ltd. was used.

Next, the silicon rubber solution impregnated with the glass micro hollow spheres 3 is degassed in a vacuum vessel for 0.1 to 0.1 times.
It is cured into a sheet with a thickness of about 0.3 mm.

Next, the hardened sheet is cut into a size of an artificial defect into which the hardened sheet is to be inserted by a cutter or the like.

The cut sheet pieces are laminated on a prepreg laminate and cured to form standard defect specimens for nondestructive inspection of fiber reinforced resin composites.

Another embodiment of the method for producing the artificial defect material 1 is a two-component mixed curing type in which the glass micro hollow spheres 3 having a sphere diameter of about 30 to 150 μm are mixed and hardened by mixing a main agent with a hardening agent. The content of 3 in the silicone rubber solution before curing
Add about 0 to 60% and stir to evenly disperse the glass micro hollow spheres 3 in the silicon rubber solution, and then degas the silicon rubber solution impregnated with the glass micro hollow spheres 3 in a vacuum container. Place the defoamed solution on a smooth plate, place a heavy object with a smooth bottom on it, insert a spacer of a specified thickness between the plate and the heavy object, and further in a vacuum container. While defoaming, it is cured into a sheet having a thickness of 0.1 to 0.3 mm.

Therefore, the artificial defect material 1 in this embodiment is mainly composed of the glass micro hollow spheres 3,
Since the glass micro hollow spheres 3 have a gas inside, by arranging a few glass micro hollow spheres 3 in the thickness T direction of the sheet 2 in a dispersed manner, it is excellent against ultrasonic waves. In addition, the ultrasonic characteristics of the silicone rubber used as the sheet 2 are superior to those of the conventional polytetrafluoroethylene sheet, although not at the air level.

Further, the artificial defect material 1 in the present embodiment
Uses silicone rubber as a binder, it is highly flexible and has excellent workability.

[0023]

EXAMPLE As shown in FIGS. 2 (a) and 2 (b), the inventors of the present invention used four kinds of artificial defect materials indicated by reference signs A, B, C and D,
Prepare a piece cut into a size of 25 mm × 25 mm,
2/3 t from the surface of the CFRP plate 4 having a thickness t of 4.4 mm,
The CFRP test piece 5 was manufactured by inserting the CFRP plate 4 from the back surface into a 1 / 3t portion, stacking the CFRP plate 4 and curing the CFRP plate 4.

The artificial defect material A is silicon rubber containing glass micro hollow spheres (artificial defect material 1 of the present invention), the artificial defect material B is silicon rubber, the artificial defect material C is a lead plate, and the artificial defect material D is conventional. It is a polytetrafluoroethylene sheet as a material.

The characteristics of each artificial defect material A, B, C, D are shown in Table 1.
Shown in.

[0026]

[Table 1] Table 2 shows the results of ultrasonic flaw detection tests using CFRP test pieces 5 containing the artificial defect materials A, B, C, and D.

[0027]

[Table 2] In Table 2, the reception sound pressure ratio is an experimental value of the ultrasonic flaw detection reception sound pressure ratio of the CFRP test piece 5 (a comparison value with a constant transmission voltage and reception sensitivity). The theoretical reflectance is a theoretical reflectance obtained from the acoustic impedance (density × sound velocity) of the CFRP plate 4 and the artificial defect plates A, B, C and D.

This reflectance is given by the following equation.

[0029]

[Equation 1] As shown in Table 2, in the artificial defect material A, a well-balanced low reception sound pressure ratio was measured in both the transmission method and the reflection method over a wide frequency range of 1 to 5 MHz. The artificial defect material B has a lower received sound pressure ratio in the reflection method than the artificial defect material A, but has a considerably higher received sound pressure ratio in the transmission method than the artificial defect material A and is not balanced. The artificial defect material C showed a received sound pressure ratio lower than that of the artificial defect material A at a frequency of 1 MHz in the reflection method, but was considerably higher than the artificial defect material A in the received sound pressure ratio in the reflection method of other frequencies and the transmission method. It showed a high received sound pressure ratio. As described above, the artificial defect material D adheres to the inside of the circle in FIG. 2 in this test piece 5, and the received sound pressure ratio of Table 2 measured at this portion is compared with any other artificial defect material in the transmission method. However, it showed a very high value.

There are two methods of ultrasonic flaw detection, a transmission method and a reflection method, and the artificial defect material is required to be a well-balanced material exhibiting excellent characteristics with respect to both methods. The artificial defect material A has excellent characteristics in both the transmission method and the reflection method, and it can be seen that it is the optimum material as the artificial defect material.

In this embodiment, the content of the glass micro hollow spheres in the artificial defect material is 50%. However, when the content of the glass micro hollow spheres is 30%, the artificial defect material permeation method is used. It has been confirmed by experiments by the inventors of the present invention that the attenuation factor in Example 2 and the reflectance by the reflection method are slightly lowered, but they are sufficient as the ultrasonic characteristics of the artificial defect material.

The content of the glass micro hollow spheres is 60%.
If it is higher than 0.1, the strength of the artificial defect material becomes insufficient because the bonding base material becomes insufficient.

[0033]

Industrial Applicability As described above, the artificial defect material of the present invention is formed by containing glass micro hollow spheres in a sheet, and is manufactured by laminating this on a prepreg laminate and heating and curing. Therefore, it shows excellent attenuation property in ultrasonic flaw detection transmission method, is not affected by the high and low frequency of ultrasonic flaw detection, and has a reflectance of 3 times or more compared with polytetrafluoroethylene sheet in ultrasonic flaw detection method. Therefore, it is possible to obtain excellent characteristics with respect to ultrasonic waves.

In the artificial defect material of the present invention, the glass micro hollow spheres have a diameter of 30 to 150 μm and the sheet has a thickness of 0.1 to 0.3 mm. It is possible to disperse two or three pieces in the thickness direction of the material, which makes it possible to further improve the characteristics with respect to ultrasonic waves. In addition, the content of the glass micro hollow spheres is 30
By setting the content to -60%, uniform high ultrasonic characteristics can be obtained over the entire area of the sheet.

In the method for producing an artificial defect material of the present invention, glass micro hollow spheres are uniformly dispersed in a two-liquid mixed curing type unhardened silicone rubber, and this is defoamed in a vacuum container to a predetermined thickness. Since it is cured as a sheet, the glass micro hollow spheres can be easily and uniformly dispersed in the sheet.

The method for producing an artificial defect material of the present invention is
Glass micro hollow spheres are evenly dispersed in a two-liquid mixed curing type unhardened silicone rubber, degassed in a vacuum container and then placed on a smooth plate, and a heavy object with a smooth bottom surface Place a spacer of a specified thickness between the plate and the heavy object, and then cure while degassing in a vacuum container to cure it as a sheet of a specified thickness. The spheres can be easily and uniformly dispersed.

[Brief description of drawings]

FIG. 1 is a perspective view showing an artificial defect material of a fiber-reinforced resin composite material according to an embodiment of the present invention.

FIG. 2 (a) is a plan view showing the configuration of a CFRP test piece used in an experiment conducted by the present inventors, and FIG. 2 (b) is (a).
FIG.

[Explanation of symbols]

1 Artificial defect material 2 Bonding base material 3 Glass micro hollow spheres 4 CFRP plate 5 CFRP test piece T thickness

Continuation of front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) G01N 29/00-29/28 G01N 23/00-23/227

Claims (8)

(57) [Claims] 1. An artificial defect material of a fiber reinforced resin composite material, characterized in that glass microhollow spheres are contained in a sheet. 2. The artificial defect material of the fiber-reinforced resin composite material according to claim 1, wherein the sheet is a two-liquid mixed curing type silicone rubber. 3. The glass micro hollow spheres have a spherical diameter of 30 to 150 μm.
The artificial defect material of the fiber-reinforced resin composite material according to claim 1 or 2, wherein the sheet thickness is m and the sheet thickness is 0.1 to 0.3 mm. 4. The content of glass micro hollow spheres is 30 to 60%.
The artificial defect material of the fiber-reinforced resin composite material according to any one of claims 1 to 3, wherein 5. A glass microhollow sphere is uniformly dispersed in a two-liquid mixed curing type silicone rubber before curing, and this is cured as a sheet having a predetermined thickness while defoaming in a vacuum container. A method for manufacturing an artificial defect material of a fiber-reinforced resin composite material. 6. Microscopic hollow glass spheres are uniformly dispersed in a two-liquid mixed curing type silicone rubber before curing, which is degassed in a vacuum container and then placed on a smooth plate, and the bottom surface is placed thereon. Is characterized by placing a smooth heavy object, inserting a spacer of a predetermined thickness between the plate and the heavy object, and further curing while defoaming in a vacuum container to cure it as a sheet of a predetermined thickness. A method for producing an artificial defect material of a fiber-reinforced resin composite material. 7. The glass micro hollow spheres have a diameter of 30 to 150 .mu.m.
7. The method for producing an artificial defect material for a fiber-reinforced resin composite material according to claim 5, wherein the sheet has a thickness of 0.1 to 0.3 mm. 8. The content of glass micro hollow spheres is 30 to 60%.
The method for producing an artificial defect material of a fiber-reinforced resin composite material according to any one of claims 5 to 7, wherein