JP3002504B2 - How to apply internal and external pressure to structures - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for applying internal and external pressure to a structure, and particularly to a structure suitable for a large structure such as a vehicle and an airplane, where the internal and external pressures act. And a method for applying internal / external pressure.

[Conventional technology]

In the conventional pressure applying apparatus and method, as shown in FIG. 8, the inside of the structure 2 is directly pressurized or depressurized.
For example, when performing an internal pressure test of a vehicle body, a method of supplying air from the atmospheric pressure state to a predetermined pressure by a pressurizing device 4 (such as a compressor) in a state where the vehicle body is sealed is used. In this conventional apparatus and method, when pressurization and depressurization are repeatedly performed, it is necessary to release the inside of the structure 2 to the atmospheric pressure once, so that there is a problem that the time per cycle is extremely long. . Further, there is a disadvantage that the state inside the structure 2 cannot be easily observed. Further, when measuring the stress or the like inside the structure 2, it is necessary to take out the wiring from the measuring device, but there has been a problem that an airtight process is required for that.

Furthermore, when the inside of the structure 2 is pressurized,
In order to prevent accidents due to destruction, equipment for safety measures such as covering the structure 2 was required.

As a conventional pressure application test method, for example, a method described in “Aerospace Engineering Handbook”, edited by the Japan Society of Aeronautics and Astronautics, published on Mar. 20, 1974, pages 915 to 918, published by Maruzen Co., Ltd. can be mentioned.

[Problems to be solved by the invention]

In the above prior art, when applying internal pressure and external pressure to a structure using a gas such as air and nitrogen gas, it takes a long time particularly to reduce the pressure. For example, when an internal pressure is applied to a sealed place such as a vehicle body or an outer cylinder from an atmospheric pressure state to a predetermined pressure state, and then the pressure is reduced from the exhaust port to the atmospheric pressure,
As the pressure approached the atmospheric pressure, the rate of pressure decrease slowed. Further, when the pressure is reduced from the atmospheric pressure to the negative pressure side by the vacuum pump or the exhaust pump, the exhaust speed is slower than the application of the internal pressure, and it takes time to reach a predetermined pressure. For this reason, when performing a fatigue test by repeatedly applying internal and external pressures to a structure, there is a problem that one cycle time is longer than that of repeated concentrated loads, the test is long, and a great deal of labor is required. .

Furthermore, in the above-mentioned conventional technology, the inside of the structure is pressurized or depressurized, and there is a problem that the same conditions as those used in a vehicle or an aircraft cannot be reproduced.

An object of the present invention is to pressurize or depressurize the outside of a structure while maintaining the inside of the structure being a test object at substantially atmospheric pressure, to match the structure to its use conditions, and for a short time. It is an object of the present invention to provide an apparatus and a method for applying internal and external pressure to a structure capable of performing a fatigue test.

[Means for solving the problem]

The object is to pressurize a space between a structure having a living space and an outer cylinder that accommodates the structure, and at the same time depressurize a decompression tank that can communicate with the outer cylinder. This is achieved by depressurizing the space between the two and simultaneously pressurizing the pressurizing tank that can communicate with the outer cylinder.

[Action]

According to the inside / outside addition method, the pressurizing and depressurizing of the pressurizing tank and the depressurizing tank are performed in reverse to the pressurizing and depressurizing of the outer cylinder, so that the pressurizing and depressurizing of the outer cylinder are performed in a short time. Can be.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

FIG. 1 shows the configuration of an internal / external pressure applying device for a structure to which the present invention is applied. 1 is an outer cylinder surrounding the structure 2, and 3 is a passage which can enter and exit the structure 2. 4 is a pressurizing device constituted by, for example, a compressor or the like, 5
Is a pressurizing tank maintained at a pressure higher than the atmospheric pressure. Reference numeral 6 denotes a pressure reducing tank maintained at a pressure lower than the atmospheric pressure, and reference numeral 7 denotes an exhaust device for reducing the pressure in the pressure reducing tank 6. Numerals 8 to 11 are valves. Reference numeral 12 denotes a space formed between the outer cylinder 1 and the structure 2, and the structure 2 is formed by increasing and decreasing the pressure in this space.
That is, the external pressure and the internal pressure act on. The pressurizing device 4 and the pressurizing tank 5 are pressurizing means, and the exhaust device 7 and the depressurizing tank 6 are pressure reducing means.

Next, the operation of the internal / external pressure applying device will be described. First, the pressurizing tank 5 is pressurized by the pressurizing device 4 to a predetermined pressure. On the other hand, the pressure reducing tank 6 is reduced to a predetermined pressure by an exhaust device 7, for example, an oil rotary vacuum pump. At this time, a valve 9 of a pipe connecting the pressurizing tank 5 and the outer cylinder 1 and a valve 10 of a pipe connecting the outer cylinder 1 and the depressurizing tank 6 are provided.
Is closed.

Next, the valve 8 and the valve 11 are closed, and the valve 9 is opened. Thereby, the compressed air in the pressurizing tank 5 flows into the space 12 between the outer cylinder 1 and the structure 2. When this state is maintained for a certain period of time, the structure 2 which was in the atmospheric pressure state
External pressure acts on the When the space 12 reaches a predetermined pressure, the valve 9 is closed, and then the valve 10 of the exhaust system is opened. At the same time, the valve 8 is opened to return the pressure in the pressurizing tank 5 to the initial pressure, and the pressurizing device 4
Pressurize inside. When the valve 10 is opened, the space 12 is at a higher pressure than the pressure reducing tank 6, so that the air in the space 12 flows into the pressure reducing tank 6. When this state is maintained for a certain time, the pressure in the space 12 can be reduced to a predetermined pressure. At this time, the internal pressure acts on the structure 2 because the space 12 has a lower pressure than the structure 2. When the pressure in the space 12 is reduced to a predetermined pressure, the valve 10 is closed, the valve 11 is opened, and the pressure in the pressure reducing tank 6 is reduced by the exhaust device 7 to the initially set pressure. If the pressure in the pressurizing tank 5 is increased to the initial pressure by the pressurizing device 4 within the time for reducing the pressure in the depressurizing tank 6 to the initial pressure, the space 12 can be continuously pressurized.

If the above operation is performed in a predetermined cycle, the internal and external pressure application of the structure 2 can be repeatedly performed. FIG. 2 shows an example of the pressure fluctuation in the space 12 between the outer cylinder 1 and the structure 2, and the pressure fluctuation in the pressurizing tank 5 and the depressurizing tank 6. 13 shows an example of the waveform of the pressure fluctuation in the space 12, that is, the waveform of the pressure fluctuation acting on the structure 2, 14 is the waveform of the pressure fluctuation in the pressurizing tank, and 15 is the waveform of the pressure fluctuation in the depressurizing tank. An example is shown. The pressure fluctuation 13
Is repeated between a pressure higher than the atmospheric pressure and a pressure lower than the atmospheric pressure.However, it is also possible to apply a pressure fluctuation above the atmospheric pressure or a pressure fluctuation in a low vacuum region and a high vacuum region below the atmospheric pressure. it can. In FIG. 2, the linear portions indicated by 16, 17, 18, 19, 20, 21 are the valve opening and closing times. The valve opening / closing time can be reduced by installing a valve that can instantaneously operate the valve, such as a solenoid valve, in the valves 8 to 11.

According to this embodiment, since the inside of the structure 2 is always at the atmospheric pressure, the inside of the structure 2 can be observed during the test (temporarily interrupting the pressure fluctuation) by entering and exiting the passage 3. There is an advantage that it can be easily performed. Also, when stress is measured inside the structure 2 by a strain gauge or the like, wiring for measurement can be performed using the passage 3, and special airtight processing for the wiring for measurement is not required.

Next, another embodiment of the internal / external pressure applying apparatus to which the present invention is applied will be described with reference to FIGS. First, the internal / external pressure applying device shown in FIG. 3 includes an outer cylinder 1, a structure 2, a passage 3, a space 12 between the outer cylinder 1 and the structure 2, a pressurizing device 4 as pressurizing means, Pressure reducing device as a pressure reducing means and valves 8, 11
It consists of. According to the present embodiment, the pressurizing tank and the depressurizing tank and the valves attached to these tanks are not required as compared with the first embodiment, so that the apparatus itself can be made compact. In this embodiment, since the application and decompression forces are applied to the outside of the structure 2, the use condition can be reproduced, and the communication passage 3 is provided, so that the inside can be confirmed. It has the same effect as the embodiment.

Next, another embodiment of the internal / external pressure applying method according to the present invention will be described as a fourth embodiment.
This will be described with reference to the drawings. The internal / external pressure applying device shown in this figure is almost the same as that of the embodiment shown in FIG. 3, but in this embodiment, the inside of the structure 2 and the space between the structure 2 and the outer cylinder 1 are different. Both the space 12 can be pressurized and depressurized. Next, a method for applying internal / external pressure according to the present embodiment will be described. When the structure 2 is pressurized, the space 12 is pressurized by the pressurizing device 4 and the inside of the structure 2 is depressurized by the pressure reducing device 7. At this time, the structure 2 is in a state where external pressure is applied.
On the other hand, in order to bring the structure 2 into a state in which the internal pressure is applied,
At the same time as the inside of the structure 2 is pressurized by the pressurizing device 4, the space 12 is depressurized by the depressurizing device 7. This operation is performed by opening and closing the valves 8a and 8b and the valves 11a and 11b, and pressurizes and depressurizes the structure 2. According to the present embodiment, the pressurizing time and the depressurizing time can be shortened compared to the embodiment shown in FIG. Thus, the number of cycles of pressurization and depressurization can be increased in a short period of time. Further, the whole apparatus can be made compact.

Next, FIG. 5 shows an application example of the outer cylinder 1 having a structure capable of partitioning the inside of the outer cylinder 1 into a plurality of airtight chambers. By partitioning the outer cylinder 1 into a plurality by the partition plate 22,
Pressure fluctuation can be applied according to the size of the structure.

FIG. 6 shows an internal / external pressure applying device in which the pressurizing tank 5 and the depressurizing force tank 6 are arranged in one container. Thus, the area occupied by the entire apparatus can be reduced, and the volumes of the pressurizing tank 5 and the depressurizing tank 6 can be arbitrarily changed by the movable partition plate 23. In addition, by providing the pressurizing tank 5 and the depressurizing tank 6, the test time can be shortened.
In the point that the inside can be confirmed, the same effect as that of the one embodiment can be achieved.

FIG. 7 shows an application example of the outer cylinder 1. The outer cylinder 1 is connected by a flange 24 so that it can be divided into a plurality. Thereby, the volume of the outer cylinder 1 can be arbitrarily changed according to the size and length of the structure.

〔The invention's effect〕

According to the present invention, it is possible to perform a fatigue test by matching a structure to be tested with its use conditions,
The condition inside the structure can be inspected with a simple configuration.

Further, by performing the pressurization and decompression of the pressurized tank and the depressurized tank while using the opposite tanks, the fatigue test can be performed in a short time.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing an embodiment of the internal / external pressure applying device according to the present invention, FIG. 2 is a graph showing the pressure fluctuation state of the outer cylinder, pressurizing tank and depressurizing tank of FIG. 1, FIG. 4th
FIGS. 6 and 7 are circuit diagrams showing another embodiment of the internal and external pressure applying device according to the present invention, and FIGS. 5 and 7 are each another embodiment of the outer cylinder used in the internal and external pressure applying device according to the present invention. FIG. 8 is a circuit diagram showing a conventional pressure applying device. 1 ... outer cylinder, 2 ... structure, 3 ... passage, 4 ... pressurizing device, 5 ... pressurizing tank, 6 ... depressurizing tank, 7 ...
Decompression device

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI G01N 3/36 G01N 3/36 (72) Inventor Moritari Hattori 794, Higashitoyoi, Katsumatsu-shi, Yamaguchi Prefecture Inside the Kasado Plant of Hitachi, Ltd. (72) Inventor Takenao Okumoto 794 Kazato Higashi Toyoi, Kudamatsu City, Yamaguchi Prefecture Inside the Kasado Plant, Hitachi, Ltd. References JP-A-61-44555 (JP, U) JP-A-63-63742 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01M 19/00 G01N 3/36 G01M 3 / 26 G01M 3/32 G01M 3/00

Claims (1)

(57) [Claims] 1. A pressure reducing tank which can communicate with the outer cylinder while simultaneously pressurizing a space between a structure having a living space and an outer cylinder accommodating the structure. A method for applying internal / external pressure to a structure, comprising depressurizing a space between the cylinder and a pressurizing tank at the same time as communicating with the outer cylinder.