JP7132634B2 - Expansion structure and its expansion method - Google Patents

Description

The present invention relates to a deployment structure and its deployment method.

The deployment structure is generally configured such that the deployment portion expands. However, when the deployment portion expands, the area and volume after deployment increase compared to before deployment, and the accommodation capacity after deployment decreases.

For example, in the case of a rocket nozzle, the larger the opening ratio, the higher the navigation performance, so a rocket nozzle having a large opening ratio at the end of the nozzle is preferable.

Patent Literature 1 discloses a nozzle that employs a configuration in which the entire nozzle is folded with geometrically complex creases. This makes it possible to realize a nozzle shape that has a large opening ratio and is compact when accommodated.

U.S. Pat. No. 4,707,899

However, for example, in the folding nozzle of Patent Document 1, many creases are formed when the nozzle is folded, and crease marks remain in the folded portion even after the nozzle is unfolded from the folded state.

If even a small crease mark remains on the rocket nozzle, it may cause melting due to local heating due to flames from the rocket engine during launch or navigation. In addition, crease marks cause a decrease in buckling strength.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a deployment structure that can be made compact when stored before or after deployment and that does not leave crease marks. Also provided is a method of containing and deploying the deployment structure.

The present invention has the following configurations (1) to (7).
(1) A deployment structure including a superelastic alloy and capable of storing a deployment portion within the elastic deformation range of the superelastic alloy.
(2) The deployable structure according to (1), wherein the deployable structure is a rocket nozzle.
(3) The rocket nozzle includes a first portion on the front end side and a second portion on the rear end side, and the first portion is made of a fiber-reinforced composite material or a heat-resistant alloy, and is the deployment portion. The deployment structure according to (2), wherein the second portion is composed of the superelastic alloy.
(4) When stored, the diameter of the virtual circle circumscribing the rear end portion after being distorted is distorted so as to be smaller than the diameter of the circumscribing circle on the front end side before being distorted, and the distorted state is maintained by the distorted shape fixing member. The deployment structure of (2) or (3), which is fixed.
(5) The deployment structure according to (4), wherein the distorted shape fixing member is a knot wound around the rear end.
(6) A deployment method for storing or deploying the deployment structure according to any one of (1) to (5) above,
a step of distorting the deployment structure within an elastic deformation range;
fixing the deployed structure in the distorted state with a distorted state fixing member;
A deployment method comprising
(7) The deployment method according to (6), wherein the distorted deployment structure is deployed to its original shape by removing the distorted shape fixing member.

According to the present invention, it is possible to provide a deployment structure that has a compact shape before and after deployment and does not leave crease marks. A method of containing or deploying the deployment structure can also be provided.

BRIEF DESCRIPTION OF THE DRAWINGS It is sectional drawing which showed the outline of the nozzle for rockets which concerns on one embodiment of this invention. It is a figure which shows the nozzle for rockets which concerns on one embodiment of this invention. It is a figure which shows the nozzle for rockets which concerns on one embodiment of this invention, and is a figure which also shows the process to bend. It is a figure which shows the nozzle for rockets which concerns on one embodiment of this invention, and is a figure which also shows the process to bend. It is a figure which shows the nozzle for rockets which concerns on one embodiment of this invention, and is a figure which also shows the process to bend. It is a figure which shows the nozzle for rockets which concerns on one embodiment of this invention, and is a figure which also shows the process to bend. It is a figure which shows the nozzle for rockets which concerns on one embodiment of this invention, and is a figure which shows the distorted state. It is a perspective view showing an example of a jig for distorting a nozzle for rockets concerning one embodiment of the present invention. FIG. 4 shows changes in atomic positions in superelasticity and shape memory. FIG. 4 is a diagram showing a stress-strain curve when a Ti-4.5Al-3V-2Fe-2Mo alloy is annealed at 1073K for 10.8ks and water-cooled. Fig. 3 shows the shape and dimensions of a quarter model of a rocket nozzle;

A rocket nozzle that is an embodiment of the present invention will be described below with reference to the drawings. In addition, the present invention is not limited by the description of the following embodiments.

FIG. 1 is a schematic cross-sectional view showing a rocket motor 1 equipped with a nozzle according to this embodiment. The nozzle 10 of the rocket motor 1 according to this embodiment consists of a fixed nozzle 11 portion and a bendable nozzle 12 portion. ) and fixed. The bendable nozzle 12 has a truncated cone shape, and the rear end portion of the fixed nozzle 11 and the tip side portion of the bendable nozzle 12 (the upper portion in FIG. 1) have the same inner diameter. The fixed nozzle 11 is made of, for example, a fiber-reinforced composite material or a heat-resistant alloy, like ordinary nozzles. The deflectable nozzle 12 is constructed from a superelastic alloy.

Here, the superelastic alloy forming the bendable nozzle 12 (deployment portion) will be described. If an attempt is made to produce a bendable nozzle with ordinary metal, it is conceivable to make the thickness sufficiently thin so as to bend it as will be described later. However, it is difficult to maintain properties such as strength and heat resistance required for rocket nozzles, for example, with simply thin metals. On the other hand, normal metal must be thick enough to have the strength required for a nozzle. , it is difficult to restore the original state by its own elastic force.

A superelastic alloy can be restored to its original state by its own elastic force by being deformed within the elastic deformation range. By containing the superelastic alloy in the unfolding portion, it is possible to obtain a compact shape before and after unfolding, and it is possible to realize a unfolding structure that does not leave crease marks. Here, the term "superelasticity" refers to a phenomenon in which deformation caused by applying stress to an alloy exhibiting thermoelastic martensitic transformation recovers its shape after unloading without heating. In FIG. 4, for reference, the top row shows changes in atomic positions in slip deformation, the middle row shows changes in atomic positions in superelasticity, and the bottom row shows changes in atomic positions in shape memory effect. Superelasticity transforms into a shape memory effect when the temperature is below the transformation temperature. A superelastic alloy placed just above the transformation temperature is in the matrix state under no stress. When stress is applied here, stress-induced martensite transformation occurs, and martensite variants in the direction of stress relaxation are preferentially generated and grown, and the shape of the entire material changes. Next, when the load is removed, if the temperature of the mother phase is originally stable, the reverse transformation proceeds only by the removal of the load, and the shape is recovered. In this way, superelastic properties are exhibited.

As the superelastic alloy, there is no particular limitation, and for example, Ni--Ti system alloy, Cu--Zn system alloy, Ni--Al system alloy, etc. can be used. Examples of Ni--Ti alloys include Ni--Ti alloys containing 49 to 52 atomic % Ni. Cu--Zn alloys include, for example, Cu--Zn alloys containing 38.5 to 41.5% by weight of Zn. Examples of Ni--Al alloys include Ni--Al alloys containing 36 to 38 atomic % Al. However, these materials must be thin plate materials.

As the superelastic alloy, in addition to the Ni-Ti alloy, Cu-Zn alloy, and Ni-Al alloy mentioned in the previous section, a near β-Ti alloy is heated at about 600 to 1000°C for about 1 to 3 hours. After that, a thin plate material may be used in which a heat treatment such as immersing in water and quenching to room temperature is performed to develop superelastic properties.
More preferably, an alloy obtained by annealing and water-cooling a Ti-4.5Al-3V-2Fe-2Mo alloy (JFE Steel SP-700) can be used as the superelastic alloy. FIG. 5 is a diagram showing a stress-strain curve when a Ti-4.5Al-3V-2Fe-2Mo alloy is annealed at 1073K for 10.8ks and water-cooled. In the stress-strain curve of FIG. 5, after applying a strain of 3% at room temperature, the residual strain remains at about 1%, and the elastic recovery strain is about 2%, indicating superelasticity. A superelastic alloy having such superelasticity can be used to construct the deployable structure of the present invention. Of course, the deployable structure of the present invention can also use a superelastic alloy with better properties.
In order to obtain superelasticity at room temperature, it is preferable to anneal the above-mentioned superelastic alloy at a temperature of 1063K to 1083K for 600ks or more and to cool it rapidly by water cooling (293K). The martensite transformation temperature depends on the volume fraction of the α phase, and when the annealing temperature is lower than 1063K, the martensite transformation temperature becomes too low relative to room temperature due to the increase in the volume fraction of the α phase, and when stress is applied, This is because superelasticity cannot be obtained because slip deformation occurs prior to stress-induced martensite transformation. Therefore, the annealing temperature is preferably 1063K or higher. On the other hand, if the annealing temperature is higher than 1083 K, the martensite transformation temperature becomes too high relative to room temperature due to the decrease in the volume fraction of the α phase, and the shape memory effect is exhibited, making it impossible to obtain superelasticity. . Therefore, the annealing temperature is preferably 1083K or lower. From these, the suitable annealing temperature range was 1063K to 1083K.

FIG. 2 is a diagram showing the shape of a rocket nozzle according to one embodiment of the present invention. In FIG. 2, by arranging a mesh on the surface of the nozzle, the state of deformation can be expressed. FIG. 2A is a diagram showing a rocket nozzle before elastic deformation.

Figures 2B-2E are diagrams of the rocket nozzle 12 showing the process of warping. FIG. 2B shows a state in which a portion (left end region and right end region) of the outer surface of the rocket nozzle 12 (left end region and right end region) is deformed inward by applying force from the outside. Although not shown in FIG. 2B, the opposite side (back side) of the paper must also be deformed by applying force from the outside to a part of the outer surface of the rocket nozzle 12 .

In FIG. 2C, a portion of the outer surface of the rocket nozzle 12 (the left and right end regions) is subjected to an external force, and a central region between the left and right end regions is also subjected to a force to It shows a state in which the amount of deformation is greater than in FIG. 2B. Although not shown in FIG. 2C, the opposite side (back side) of the paper must also be deformed by applying force from the outside to a part of the outer surface of the rocket nozzle 12 .

In FIGS. 2D and 2E, the deformation amount is larger than that in FIG. 2C, and the deformed state is such that the left end region, the central region, and the right end region have a large concave ratio.

FIG. 2F shows a state in which the amount of deformation is even greater than in FIGS. 2D and 2E, and the proportions of depressions in the left end region, the central region, and the right end region are increased, and the distortion is completed. The diameter of an imaginary circle circumscribing a plurality of vertices on the upper side (rear end side of the nozzle) in FIG. 2F is smaller than the diameter of the circle on the lower side (tip side of the nozzle) in FIG. 2F. As a result, the rocket nozzle, which is a deployment structure, can be stored compactly on the rear end side of the nozzle that is extended during deployment.

Further, the nozzle 12 of FIG. 2F can be expanded into the shape of the rocket nozzle in the state of FIG. 2A by releasing the force applied from the outside, and the expanded structure does not leave crease marks.

The deployment method for storing or deploying the deployment structure of this embodiment includes:
(a) bending the deployable structure within an elastic deformation range;
(b) fixing the distorted deployment structure with a distorted state fixing member;
is a deployment method comprising

Further, by removing the distorted shape fixing member, the distorted deployment structure can be deployed to its original shape.

An example of a method for storing the deployment structure will be shown below with reference to FIG. As shown in FIG. 3, only the tip of the truncated conical nozzle 12 (expanded portion) is fixed to the substrate, and the nozzle 12 is distorted using a jig 20 . The nozzle 12 is arranged so that its tip side faces downward, the tip side is fixed to the substrate, and the rear end side faces upward. The jig 20 body may have a cylindrical shape with a larger diameter than the rear end of the nozzle 12 . There are columnar portions parallel to the axis at six positions equiangularly spaced from each other in the circumferential direction of the jig 20, and each columnar portion is provided with two holes for inserting the rod members 21 from the outside. ing. The nozzle 12 can be folded most easily by forming a hole in each of the six columnar portions, but the number of holes is not limited to this.

Next, the rod member 21 is inserted from the outside into the hole of each columnar portion. Then, the tip of the rod-shaped member 21 at each location is brought into contact with the vicinity of the rear end of the nozzle 12, and each location is adjusted so that each portion of the nozzle 12 that is in contact with the tip of the rod-shaped member 21 is evenly distorted. The rod-shaped member of is pushed inward little by little. By using such a jig 20 and rod-shaped member 21, the outer surface of the nozzle 12 can be evenly pushed inward and distorted from each direction at regular intervals in the circumferential direction perpendicular to the axis of the nozzle. As for the folded shape of the nozzle, in this embodiment, it is a star shape pushed in from six directions. This uses buckling in the circumferential direction for folding, but considering the dimensions of this embodiment, the shape with a circumferential wave number of about 6 to 8 has the smallest buckling load, and the load required for folding is also small. One reason is that In addition, as we proceed with the storage after buckling, it is necessary to push in a larger amount in order to store the part that is not pushed in if the wave number is small. Since it becomes smaller and the distortion becomes larger, it is necessary to select an appropriate intermediate wave number. Furthermore, assuming actual work, an even number wave number is preferable to an odd number wave number which requires pressing the entire body evenly at the same time in order to balance forces. Considering all these factors, this model adopts a hexagram-shaped folding. However, the folded shape is not particularly limited as long as the folded shape is sufficiently small and the strain does not remain after unfolding.
We actually created a scale model of the rocket nozzle and confirmed that it can be folded and unfolded without any problems. FIG. 6 is a diagram showing the shape and dimensions of a model of a rocket nozzle. In creating a rocket nozzle model, assuming application to an actual machine, a truncated cone shape with a lower φ (small diameter) of 120 mm, an upper φ (large diameter) of 168 mm, and a height of 66.5 mm was used as a 1/4 scale. In the figure, the rolling direction is indicated by an arrow RD (rolling direction), and the direction perpendicular to the rolling is indicated by an arrow TD (transverse direction). Regarding the plate thickness, while it is necessary to withstand the circumferential stress and axial buckling due to the internal pressure of the nozzle, the strain during storage increases in proportion to the plate thickness, so it is necessary to make it as thin as possible. . Here, if the elastic recovery strain is large, the strain during storage can be increased. The Ti-4.5Al-3V-2Fe-2Mo alloy annealed at 1073K for 10.8ks and water-cooled has an elastic recovery strain of about 2%, but assuming that it is used, the above-mentioned folded shape When the plate thickness was obtained in consideration of the distortion during storage and the internal pressure of the nozzle, it was 60 μm while securing the minimum necessary safety factor. Note that this corresponds to 0.25 mm in the actual machine.

When sufficiently distorted, the knotted string is wound around the vicinity of the rear end of the nozzle 12 through the gaps in the columnar portion of the jig 20 once or several times as necessary to connect the ends. This knotted string is an example of the distorted shape fixing member of the present invention. This fixes the distorted state of the nozzle 12 . A tie wrap made of plastic, a wire made of metal, or the like can be used as the knotted string.

When the nozzle is deployed, for example, by removing the distorted shape fixing member (in the case of a knotted string, simply cutting it), the elastic force of the nozzle 12 itself immediately deploys it to the original complete truncated cone shape. be able to. Deployment of the scale model of the aforementioned rocket nozzle took less than 1 second. From this, it can be seen that even a rocket nozzle of actual dimensions deploys within 1 second. This is fast enough for the time it takes to deploy the nozzle and fire it in space.

In addition, the deployment structure of the present invention is not limited to a rocket nozzle. For example, it can be applied to a deployable structure such as an antenna for deploying in outer space, which is devised how to distort it, is stored in a small size on the ground, is transported to space, and is deployed there based on its own elastic force.

Further, the deployment method of the present invention is not limited to the storage method using the jig 20 as described above, and for example, a mold may be used to distort the deployment structure.

1 rocket motor 10 nozzle 11 fixed nozzle 12 bendable nozzle 20 jig 21 rod-like member

Claims (7)

A deployment structure comprising a super-elastic alloy, wherein no crease mark remains after deployment by making the deployment part retractable within the elastic deformation range of the super-elastic alloy. 2. The deployment structure of claim 1, wherein said deployment structure is a rocket nozzle. The rocket nozzle includes a first portion on the front end side and a second portion on the rear end side, the first portion is made of a fiber reinforced composite material, and the second portion, which is the deployment portion, is 3. The deployable structure of claim 2, comprising said superelastic alloy. When stored, the diameter of the virtual circle inscribed in the rear end after being distorted is distorted so that it is smaller than the diameter of the circle on the front end side before being distorted, and the distorted state is fixed by the distorted shape fixing member. The deployment structure according to claim 2 or 3. 5. The deployment structure according to claim 4, wherein said distorted shape fixing member is a knotted cord wound around said rear end. A deployment method for storing or deploying the deployment structure according to any one of claims 1 to 5,
a step of distorting a thin plate member constituting the deployable structure within an elastic deformation range;
a step of fixing the thin plate material in the distorted state with a distorted state fixing member;
A deployment method comprising 7. The unfolding method according to claim 6, wherein the distorted thin plate material is unfolded to its original shape by removing the distorted shape fixing member.

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