JP4998060B2 - Hydraulic pressure destruction test apparatus and test method for propellant tank for spacecraft - Google Patents

Description

  The present invention relates to a hydraulic pressure destruction test apparatus and test method for a propellant tank for a spacecraft, and more particularly, to a hydraulic pressure destruction test apparatus and a test method for a large tank that contains a liquid as a propellant in a weightless state in space.

In general, propellant tanks for spacecraft that travel in outer space such as artificial satellites have a liquid passage (channel) covered with a mesh on the inner periphery of a spherical tank in order to efficiently discharge the remaining liquid. (See Patent Document 1).
In these liquid passages, particularly mesh portions, there is a possibility of vibration fatigue failure due to liquid vibration, sloshing, and out-of-plane pressure fluctuation during satellite operation. Therefore, these propellant tanks had to be subjected to a strength test against vibration fatigue failure.
However, in the past, there was a need to conduct a destructive test on the mesh welded portion of the channel member in a state closer to the actual machine, but this was difficult to implement. Therefore, a destructive test was performed by applying a mechanical load to the mesh welded portion of the channel member.

For example, a part of the channel member 1 as shown in FIG. 11 is cut to form the jig support portion 2, and a test piece 4 in which the mesh 3 is seam welded is created. This is a destructive test as shown in FIG. The load bar 6 is inserted into the channel member 1 and the load P is applied through the steel ball 7. After the test piece 4 is lowered together with the load bar 6 and the jig support portion 2 comes into contact with the jig 8, it is possible to measure the load until the load is applied to the mesh 3 and breaks.
JP-A-9-20299 (FIG. 3)

However, when the uniform load applied to the mesh of the channel member due to liquid vibration, sloshing, or out-of-plane pressure fluctuation is replaced with a mechanical load, the shape of the indenter (pushing jig) for applying the mechanical load The effect is inevitable. For this reason, with a mechanical load, it is impossible to apply a completely uniform load to the mesh, and the strength obtained by the uniform load due to pressure is different from the concentrated load at the contact end of the indenter. Become. Therefore, it has been difficult to reproduce the fracture that occurs in the actual outer space in the above-described destructive testing of the mechanical load system.
In addition, a hydraulic vibration fatigue destruction method that is considered to be closer to reality has not been established.

  The present invention has been made in view of the above-described circumstances, and an object of the present invention is to provide a fluid pressure destruction test apparatus and a test method for a mesh portion inside a propellant tank for a spacecraft.

In the hydraulic pressure break test apparatus and test method according to the present invention, the following means are employed in order to solve the above problems.
A spacecraft propellant tank hydraulic pressure breakage test apparatus according to a first aspect of the present invention is a mesh member liquid pressure breakage test apparatus seam welded to an opening surface of a channel member, which is placed on a base member. A test piece holding base having a space that enables out-of-plane deformation of the mesh member of the test piece, a hydraulic bottom plate placed on the test piece holding base and pressing the periphery of the opening of the test piece, and the hydraulic bottom plate A membrane member placed on the cylinder, a cylinder that sandwiches the periphery of the membrane member between the hydraulic bottom plate and opens toward the test piece, and a piston inserted through the cylinder, An out-of-plane hydraulic pressure is applied to the mesh member of the test piece held on the test piece holding base by the cylinder and the piston through the membrane member.

The membrane member is rubber having a thickness of 0.2 to 1.0 mm.
In addition, a film member intrusion preventing member is provided in the axial direction of both ends of the opening of the channel member.

  A hydraulic fracture test method for a propellant tank for a spacecraft according to a second aspect of the present invention is a hydraulic fracture test method for a mesh member seam welded to an opening surface of a channel member. A test piece preparation step of providing an opening for applying pressure, a step of installing a membrane member intrusion prevention member in the axial direction of both ends of the opening of the channel member, and a membrane member breakage prevention material at the edge of the opening And a pressurizing step of applying an out-of-plane hydraulic pressure to the mesh member by a cylinder through a flexible membrane member entering from the opening.

  In the pressurizing step, a synthetic rubber adhesive is applied between the cylinder and the membrane member.

According to the present invention, the following effects can be obtained.
A hydraulic pressure destruction test apparatus for a spacecraft propellant tank according to the present invention is mounted on a base member, and a test piece holding base having a space that enables out-of-plane deformation of a mesh member of the test piece, A hydraulic bottom plate placed on the test piece holder and holding the periphery of the opening of the test piece, a membrane member placed on the hydraulic bottom plate, and a peripheral edge of the membrane member between the hydraulic bottom plate The cylinder and the piston include a cylinder that is sandwiched and opened toward the test piece, and a piston that is inserted into the cylinder, and a mesh member of the test piece that is held by the test piece holding base via a membrane member. Since the hydraulic pressure in the out-of-plane direction is applied by the above, it is possible to perform a hydraulic breakdown test close to the actual.

Further, since the membrane member is rubber having a thickness of 0.2 to 1.0 mm, it is possible to cause out-of-plane bending deformation in the mesh member that is expanded and entered from the opening and seam-welded.
Further, since the membrane member intrusion preventing member is installed in the axial direction of both ends of the opening of the channel member, the mesh member can surely cause out-of-plane bending deformation of the mesh member.

  Also, a hydraulic pressure breakage test method for a propellant tank for a spacecraft according to the present invention is a liquid pressure breakage test method for a mesh member seam welded to an opening surface of a channel member, and the liquid pressure breakage test method is applied to the channel surface of the channel member. A test piece preparation step of providing an opening for applying pressure, a step of installing a membrane member intrusion prevention member in the axial direction of both ends of the opening of the channel member, and a membrane member breakage prevention material at the edge of the opening Since it consists of a step of installing and a pressurizing step of applying hydraulic pressure in the out-of-plane direction to the mesh member through a flexible membrane member entering from the opening, a hydraulic pressure breakdown close to actual A test can be performed.

  Moreover, since a synthetic rubber adhesive is applied between the cylinder and the membrane member in the pressurizing step, liquid leakage can be prevented.

Hereinafter, embodiments of a hydraulic pressure destruction test apparatus and a test method for a propellant tank for a spacecraft according to the present invention will be described with reference to the drawings.
FIG. 1 is a longitudinal sectional view showing a hydraulic fracture testing apparatus according to an embodiment of the present invention. 2 is a cross-sectional view taken along line AA in FIG. 3 is a cross-sectional view taken along line BB in FIG.

The hydraulic pressure breaking test apparatus M is an apparatus for testing the durability of the channel mesh member 61 of the satellite propellant tank 60 described later.
The hydraulic fracture test apparatus M is placed on the base member 10 and has a test piece holding base 12 having a space 11 that enables an out-of-plane deformation of a mesh member 27 (see FIG. 7) of a test piece 18 described later. A hydraulic bottom plate 13 placed on the test piece holder 12 and holding the periphery of the opening of the test piece, a membrane member 14 (see FIG. 5) placed on the hydraulic bottom plate 13, and the membrane member 14 The cylinder 15 includes a cylinder 15 that has a peripheral edge between the hydraulic bottom plate 13 and opens toward the test piece, and a piston 16 that is inserted through the cylinder 15.

The base member 10 is fixed to the foundation by bolts 17.
The test piece holding base 12 has a space 11 that allows the mesh member of the test piece to be deformed out of the plane, and has a concave groove 19 that holds both ends of the test piece 18 so as to span the space 11. is doing.

The specimen holder 12 is fixed to the base member 10 with bolts 20.
The hydraulic bottom plate 13 has an opening 13 a substantially equal to the opening formed in the test piece at the center, and presses the periphery of the opening of the test piece 18. Further, the opening 13 a is expanded in a tapered shape toward the opening of the cylinder 15 installed on the upper side, and is fixed to the cylinder 15 with a bolt 25.

  The membrane member 14 only needs to have elasticity and water tightness, and natural rubber, synthetic rubber, or the like can be used. The thickness may be in the range of 0.2 mm to 1.0 mm.

  The cylinder 15 is fixed to the test piece holder 12 with bolts 21. A piston 16 is inserted into the cylinder 15 via an O-ring 22. An upper pressing plate 23 is attached to the upper end of the cylinder 15 with bolts 24 in order to prevent the piston 16 from coming off.

FIG. 4 is a plan view of the hydraulic pressure breaking test apparatus. FIG. 5 is an enlarged sectional view taken along the line CC of FIG.
The membrane member 14 is sandwiched between the hydraulic bottom plate 13 and the cylinder 15 and covers the opening 13 a of the hydraulic bottom plate 13. In addition, a synthetic rubber adhesive is applied between the membrane member 14 and the cylinder 15 to serve as a seal and hold the applied pressure.

FIG. 6 is an explanatory diagram showing an example of a propellant tank for satellite.
Inside the satellite propellant tank 60 is provided a channel mesh member 61 that guides the propellant that has passed through the mesh and entered the channel to the outlet by a surface tension effect in a weightless space.

  In the channel mesh member 61, vibration fatigue failure may occur due to liquid vibration, sloshing, and out-of-plane pressure fluctuation during flight of the satellite. Accordingly, the channel mesh member 61 of the satellite propellant tank 60 needs to be subjected to a strength test against vibration fatigue failure.

FIG. 7 is a plan view of a test piece used in a hydraulic pressure destruction test apparatus for a propellant tank for a satellite.
FIG. 8 is a side view in which a part of the test piece is cut away. 9 is a cross-sectional view taken along the line DD of FIG.
In the test piece 18, a mesh member 27 is seam welded to an opening surface of a channel member 26 having a predetermined length. The mesh member 27 used here is made of, for example, austenitic stainless steel, and a wire diameter of 0.035 mm is 325 per inch in the longitudinal direction of the channel, and a wire diameter of 0.025 mm is in the width direction. 2300 are arranged per inch.
In another example, 40 wires having a diameter of 0.190 mm per inch in the longitudinal direction of the channel and 400 wires having a wire diameter of 0.140 mm are disposed in the width direction per inch.
The wire diameter in the longitudinal direction and the width direction and the number per inch may be other than the two examples described above. In particular, the wire diameter is preferably 0.2 mm or less.

  Further, the test piece 18 has a rectangular opening 28 for applying a hydraulic pressure to the channel surface of the channel member 26. It is preferable that the cut surface of the opening 28 and the inner side surface of the channel are processed to be the same surface, and the corner portion is chamfered so that the membrane member 14 is not damaged.

Next, a hydraulic fracture test method using the hydraulic fracture test apparatus configured as described above and a test piece will be described.
First, the mesh member 27 is seam welded to the opening surface of the channel member 26 having a predetermined length in the test piece preparation step, and the rectangular opening portion 28 for applying the hydraulic pressure to the channel surface is cut.
At this time, the corners are chamfered by cutting so that the cut surface of the opening 28 and the inner surface of the channel are the same surface. Thereby, the test piece 18 is created.

Next, the test piece 18 is set on the test piece holding base 12. At this time, in order to prevent the membrane member from expanding and entering in the axial direction of both ends of the opening of the channel member, a membrane member intrusion preventing member 29 such as silicon is installed.
In addition, it is preferable to install a film member damage prevention material (not shown) such as a synthetic resin backing plate at the edge of the opening 28 of the set test piece 18 so that the film member 14 is not damaged.
Furthermore, a synthetic rubber adhesive is applied between the membrane member 14 and the cylinder 15 to prevent liquid leakage and maintain the pressure generated by the piston 16.

When the setting of the test piece 18 is completed, the process proceeds to the pressurizing step. Specifically, the piston 16 is lowered through the steel ball 31 by a pressurizing device (not shown).
Then, the liquid filled in the cylinder 15 receives pressure, and the membrane member 14 disposed between the hydraulic bottom plate 13 and the cylinder 15 is expanded and deformed by the hydraulic pressure. Then, the expanded membrane member 14 enters from the opening 28 and applies a fluid pressure in the out-of-plane direction to the mesh member 27.
In this way, it is possible to perform a hydraulic breakage test on the seam welded mesh of the channel member.

FIG. 10 is a diagram showing the hydraulic load range (ΔF) and the number of repetitions of fracture (Nf) by the test apparatus of the present invention.
As shown in FIG. 10, when the hydraulic load was 2000 N, the number of fracture repetitions was about 230 times and about 500 times. Further, when the hydraulic load was 1000 N, the number of repetitions of fracture was about 1800 times. Moreover, when the hydraulic load was 500 N, the number of repetitions of fracture was about 1300 times and about 4400 times.
The load ratio R shown in the figure indicates the ratio of the minimum load to the maximum load (R = minimum load / maximum load).

  From the above results, it has been found that there is a certain correlation between the hydraulic load and the number of repetitions of fracture. Thus, according to the hydraulic fracture test apparatus M and the test method according to the present embodiment, a hydraulic fracture test close to an actual machine can be performed.

  Note that the operation procedure shown in the above-described embodiment, various shapes and combinations of the constituent members, and the like are examples, and various modifications can be made based on design requirements and the like without departing from the gist of the present invention.

In the embodiment described above, the case of the propellant tank for satellites has been described as the propellant tank for spacecraft, but the present invention is not limited to this.
In addition to those for satellites, those that need to be propelled or attitude-controlled (including propellant tanks) in a weightless state, such as rockets, spacecrafts, and space stations, may be used.

It is a longitudinal cross-sectional view which shows the hydraulic pressure destruction test apparatus of the propellant tank for satellites concerning one Embodiment of this invention. It is the sectional view on the AA line of FIG. It is the BB sectional view taken on the line of FIG. It is a top view of the hydraulic pressure destruction test apparatus of the propellant tank for the satellite. FIG. 3 is an enlarged sectional view taken along the line CC in FIG. 2. It is explanatory drawing which shows an example of the propellant tank for satellites. It is a top view of the test piece used for a hydraulic fracture test apparatus. It is the side view which notched a part of the test piece. It is the DD sectional view taken on the line of FIG. It is a figure which shows the hydraulic load range ((DELTA) F) and fracture | rupture repetition number (Nf) by the test apparatus. It is a perspective view which shows the channel mesh test piece by the conventional mechanical load loading system. It is explanatory drawing of the testing apparatus by the conventional mechanical load loading system.

Explanation of symbols

DESCRIPTION OF SYMBOLS M ... Hydraulic pressure destruction test apparatus 10 ... Base member 11 ... Space 12 ... Test piece holding stand 13 ... Hydraulic bottom plate 14 ... Membrane member 15 ... Cylinder 16 ... Piston 18 ... Test piece 19 ... Concave groove 26 ... Channel member 27 ... Mesh member 28 ... Opening 29 ... Membrane member intrusion prevention member 60 ... Satellite propellant tank (propellant tank for spacecraft)
61 ... Channel mesh member P ... Load

Claims (4)

A hydraulic fracture test device for a mesh member seam welded to an opening surface of a channel member,
A test piece holder with a space placed on the base member and allowing out-of-plane deformation of the mesh member of the test piece;
A hydraulic bottom plate placed on the specimen holder and holding the periphery of the opening of the specimen;
A membrane member placed on the hydraulic bottom plate;
A cylinder that is sandwiched between a peripheral edge of the membrane member and the hydraulic bottom plate and that opens toward the test piece;
A piston inserted through the cylinder;
It consists of a membrane member intrusion prevention member installed in the axial direction at both ends of the opening of the channel member ,
A liquid in a propellant tank for a spacecraft, wherein fluid pressure in an out-of-plane direction is applied to the mesh member of the test piece held on the test piece holding table by the cylinder and the piston through the membrane member. Pressure fracture test equipment.   2. The hydraulic pressure destruction test apparatus for a propellant tank for a spacecraft according to claim 1, wherein the film member is rubber having a thickness of 0.2 to 1.0 mm. A hydraulic fracture test method for a mesh member seam welded to an opening surface of a channel member,
A test piece creating step of providing an opening for applying a hydraulic pressure to the channel surface of the channel member;
Installing a membrane member intrusion prevention member in the axial direction of both ends of the opening of the channel member;
A pressurizing step of applying an out-of-plane hydraulic pressure to the mesh member by a cylinder through a flexible membrane member entering from the opening;
A hydraulic fracture test method for a propellant tank for a spacecraft, comprising: 4. The hydraulic pressure destruction test method for a spacecraft propellant tank according to claim 3, wherein a synthetic rubber adhesive is applied between the cylinder and the membrane member in the pressurizing step .

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