WO2019138788A1

WO2019138788A1 - Deployable structure and deployable method therefor

Info

Publication number: WO2019138788A1
Application number: PCT/JP2018/046315
Authority: WO
Inventors: 伸介竹内; 佐藤　英一; 裕史戸部
Original assignee: 国立研究開発法人宇宙航空研究開発機構
Priority date: 2018-01-11
Filing date: 2018-12-17
Publication date: 2019-07-18
Also published as: JP7132634B2; JPWO2019138788A1

Abstract

Provided is a deployable structure which can be compact in form while being stored before or after deployment and which does not retain fold lines. The nozzle 10 of a rocket motor 1 is constituted by a fixed nozzle 11 and a distortable nozzle 12, and the distortable nozzle 12 is attached and affixed to the rear end (lower side in Fig. 1) of the fixed nozzle 11. The distortable nozzle 12 has a truncated cone shape, and the rear end of the fixed nozzle 11 and the leading end (upper side in Fig. 1) of the distortable nozzle 12 have substantially the same diameter. The fixed nozzle 11 is composed of a material similar to that used in regular nozzles, such as a fiber-reinforced composite material. The distortable nozzle 12 is composed of a superelastic alloy.

Description

Expansion structure and expansion method thereof

The present invention relates to an unfolding structure and an unfolding method thereof.

The deployment structure is generally configured to expand the deployment portion. However, when the deployment portion expands, the area and volume after deployment expand more than before deployment, and the accommodation after deployment decreases.

For example, in the case of a rocket nozzle, the larger the aperture ratio, the higher the navigation capability. Therefore, a rocket nozzle having a larger aperture ratio at the nozzle end is preferable.

Patent Document 1 discloses a nozzle adopting a configuration in which the nozzle is geometrically complicated and folded to fold the entire nozzle. As a result, the aperture ratio is large, and a compact nozzle shape can be realized at the time of accommodation.

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

However, for example, in the foldable nozzle of Patent Document 1 described above, many folds will be formed when folded, and even after the folded state from the folded state, fold marks will remain in the folded portion.

If any crease marks remain in the rocket nozzle, the fire from the rocket engine during launch or navigation may cause melting due to local heating. In addition, crease marks cause a decrease in buckling strength.

An object of the present invention is to provide an unfolded structure which can be made into a compact shape before being deployed or after being unfolded and which has no crease marks. Also provided is a method of housing and deploying the deployment structure.

The present invention has the following configurations (1) to (7).
(1) A developed structure that includes a superelastic alloy and is capable of containing a developed portion within the elastic deformation range of the superelastic alloy.
(2) The unfolding structure according to (1), wherein the unfolding 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, the first portion is made of a fiber reinforced composite material or a heat-resistant alloy, and is the expansion portion The expanded structure according to (2), wherein the second portion is made of the superelastic alloy.
(4) The diameter of the virtual circle circumscribing the rear end after distortion is stored so as to be smaller than the diameter of the circumscribed circle on the front end side before distortion, and the distortion state is corrected by the distortion fixing member The expanded structure according to (2) or (3), which is fixed.
(5) The unfolded structure according to (4), wherein the distorted shape fixing member is a knotted cord wound around the rear end.
(6) An expanding method for storing or expanding the expanded structure according to any one of the above (1) to (5),
Distorting the unfolded structure within an elastic deformation range;
Fixing the unfolded structure in the distorted state by a distorted state fixing member;
Deployment method.
(7) The expansion method according to (6), wherein the expanded structure in the distorted state is expanded to an original shape by removing the distorted shape fixing member.

ADVANTAGE OF THE INVENTION According to this invention, it can be made into a compact shape at the time of accommodation after expansion | deployment or after expansion | deployment, and the expansion | deployment structure which a crease mark does not remain can be provided. It is also possible to provide a method for containing or deploying the deployment structure.

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 showing a nozzle for rockets concerning one embodiment of the present 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 made to be distorted. 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 made to be distorted. 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 made to be distorted. 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 made to be distorted. It is a figure which shows the nozzle for rockets concerning one embodiment of the present invention, and is a figure which also shows the state where it was distorted. It is the perspective view which showed an example of the jig for distorting the nozzle for rockets concerning one embodiment of the present invention. FIG. 5 is a diagram showing changes in atomic position in superelasticity and shape memory. It is a figure which shows the stress-strain curve at the time of 10.8ks annealing and water cooling of Ti-4.5Al-3V-2Fe-2Mo alloy at 1073K. FIG. 6 shows the shape and dimensions of a 1⁄4 model of a rocket nozzle.

A rocket nozzle according to an embodiment of the present invention will be described below with reference to the drawings. Note that 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 the present embodiment. The nozzle 10 of the rocket motor 1 according to the present embodiment includes a portion of the fixed nozzle 11 and a portion of the distortable nozzle 12, and the distortable nozzle 12 is a portion on the rear end side of the fixed nozzle 11 (a lower portion of FIG. Is attached and fixed. The distortable nozzle 12 has a frusto-conical shape, and the inner diameter of the rear end portion of the fixed nozzle 11 and the tip end portion (upper part in FIG. 1) of the distortable nozzle 12 is the same. The fixed nozzle 11 is made of, for example, a fiber-reinforced composite material or a heat-resistant alloy as in a normal nozzle. The distortable nozzle 12 is made of a superelastic alloy.

Here, the superelastic alloy which comprises the distortable nozzle 12 (deployment part) is demonstrated. When it is going to produce the nozzle which can be made into a normal metal and which can be distorted, it is possible to make it distorted like the after-mentioned by making the thickness thin enough. However, it is difficult to maintain the properties such as strength and heat resistance required for a rocket nozzle, for example, by using only a thin metal. On the other hand, it must be thick enough to give the nozzle the necessary strength for ordinary metals, but it is difficult to distort with such thick metals, and plastic deformation occurs even if it can be distorted. , It is difficult to restore the original state by its own elastic force.

The 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 developed portion, it is possible to make it into a compact shape before being deployed or after being accommodated, and it is possible to realize a deployed structure in which no crease marks remain. Here, the term "superelasticity" refers to a phenomenon in which deformation caused by applying stress to an alloy exhibiting thermoelastic martensitic transformation undergoes shape recovery without heating after unloading. In FIG. 4, the change in atomic position in the slip deformation is shown at the top as a reference, and the change in atomic position in superelasticity is shown in the middle, and the change in atom position in the shape memory effect is shown at the bottom. Superelasticity changes to a shape memory effect when the temperature goes below the transformation temperature. The superelastic alloy placed just above the transformation temperature is in the matrix state under no stress. When stress is applied here, stress-induced martensitic transformation occurs, martensite variants in the direction of stress relaxation are preferentially generated and grown, and the shape of the entire material changes. Next, when unloading is performed, if the parent phase is originally at a stable temperature, reverse transformation proceeds only by unloading and the shape is recovered. Thus, the property of superelasticity is expressed.

The superelastic alloy can be used without particular limitation, but for example, a Ni-Ti alloy, a Cu-Zn alloy, a Ni-Al alloy, etc. can be used. Examples of the Ni-Ti-based alloy include Ni-Ti-based alloys of 49 to 52 atomic percent Ni. As the Cu—Zn-based alloy, for example, a Cu—Zn alloy of 38.5 to 41.5 wt% Zn is exemplified. As the Ni-Al based alloy, for example, a Ni-Al alloy of 36 to 38 atomic% Al is exemplified. However, these materials need to be thin sheet materials.

As the superelastic alloy, in addition to the Ni-Ti alloy, Cu-Zn alloy, Ni-Al alloy, etc. described above, heating to a near β-Ti alloy for about 1 to 3 hours at about 600 to 1000 ° C. Then, it may be immersed in water and subjected to heat treatment such as rapid cooling to normal temperature to use a thin plate material having developed a superelastic property.
More preferably, an alloy obtained by annealing / water cooling a Ti-4.5Al-3V-2Fe-2Mo alloy (SP-700 manufactured by JFE Steel) can be used as the superelastic alloy. FIG. 5 is a diagram showing a stress-strain curve when Ti-4.5Al-3V-2Fe-2Mo alloy is subjected to 10.8 ks annealing / water cooling at 1073K. In the stress-strain curve of FIG. 5, after applying a strain of 3% at room temperature, the residual strain remains at about 1%, indicating a superelasticity having an elastic recovery strain of about 2%. Such superelastic superelastic alloys can be used to construct the deployed structures of the present invention. Of course, the developed structure of the present invention can also use a superelastic alloy with better characteristics.
In order to obtain superelasticity at room temperature, it is preferable to perform annealing for 600 ks or more at a temperature of 1063 K to 1083 K with respect to the above-mentioned super elastic alloy, and to rapidly cool by water cooling (293 K). The martensitic transformation temperature depends on the volume fraction of the α phase, and when the annealing temperature is lower than 1063 K, the martensitic transformation temperature becomes too low relative to room temperature due to the increase of the volume fraction of the α phase, and stress is applied It is because super-elasticity can not be obtained because slip deformation occurs prior to stress-induced martensitic transformation. Therefore, the annealing temperature is preferably 1063 K or more. On the other hand, when the annealing temperature is higher than 1083 K, the martensitic transformation temperature becomes too high with respect to room temperature due to the decrease of the volume fraction of α phase, and the shape memory effect is exhibited and superelasticity can not be obtained. . Therefore, the annealing temperature is preferably 1083 K or less. From these, the preferable range of the annealing temperature was 1063 K to 1083 K.

FIG. 2 is a view showing the shape of a rocket nozzle according to an embodiment of the present invention. In FIG. 2, the mesh is arranged on the surface of the nozzle so that the state of deformation can be expressed. FIG. 2A is a view showing the rocket nozzle before elastic deformation.

FIGS. 2B to 2E show the rocket nozzle 12 and show the process of distortion. FIG. 2B shows that a part (left end area and right end area) is deformed inward by applying a force from the outside to part of the outer surface of the rocket nozzle 12 (left end area and right end area). Although not shown in FIG. 2B, the opposite side (back side) of the paper also has to be deformed by applying a force from the outside to a part of the outer surface of the rocket nozzle 12.

In FIG. 2C, in addition to the external force of the outer surface of the rocket nozzle 12 (left end region and right end region) being applied from the outside, force is also applied to the central region between the left end region and the right end region, It shows a state in which the amount of deformation is larger than that in FIG. 2B. Although not shown in FIG. 2C, the reverse side (back side) of the paper also has to be deformed by applying a force from the outside to a part of the outer surface of the rocket nozzle 12.

In FIG. 2D and FIG. 2E, the deformation amount is larger than that in FIG. 2C, and the deformation ratio is large in the left end region, the center region, and the right end region.

FIG. 2F shows a state in which distortion is completed because the deformation amount is larger than in FIGS. 2D and 2E, and the dent ratio in the left end region, the center region, and the right end region is increased. The diameter of an imaginary circle circumscribing the plurality of apexes on the upper side (the rear end side of the nozzle) in FIG. 2F is smaller than the diameter of the circle on the lower side (the tip side of the nozzle) in FIG. As a result, the rear end side of the expanded nozzle at the time of deployment is compactly stored in the rocket nozzle which is the deployment structure.

Moreover, the nozzle 12 of FIG. 2F can expand | deploy to the shape of the nozzle for rockets of the state of FIG. 2A by releasing the force applied from the outer side, and it becomes an expansion | deployment structure in which a crease mark does not remain.

The expansion method for storing or expanding the expansion structure of the present embodiment is
(A) distorting the unfolded structure within an elastic deformation range;
(B) fixing the unfolded structure in a distorted state by a distorted state fixing member;
Is a deployment method comprising

Also, by removing the distorted shape fixing member, the unfolded structure in the distorted state can be developed into the original shape.

Hereinafter, an example of a method of storing the expanded structure will be described with reference to FIG. As shown in FIG. 3, only the tip of the truncated cone shaped nozzle 12 (deployed portion) is fixed to the substrate, and the nozzle 12 is distorted using a jig 20. The nozzle 12 is fixed such that its front end side is fixed to the substrate with its front end side down, and its rear end side is on top. The shape of the jig 20 body may be a cylindrical shape whose diameter is larger than the rear end of the nozzle 12. At six angularly equidistant angular positions in the circumferential direction of the jig 20, there are pillars parallel to the axis, and each pillar has two holes for inserting the rod-like members 21 from the outside. ing. Although the nozzle 12 can be most easily folded by providing a hole in each of the six columnar parts, the number of places where the holes are provided is not limited thereto.

Next, the rod-like member 21 is inserted into the hole of each columnar portion from the outside. Then, each end of the rod-like member 21 at each portion is brought into contact with the vicinity of the rear end of the nozzle 12, and each portion of the nozzle 12 in contact with the tip of the rod-like member 21 is distorted uniformly. Push the bar-like member of the inside slightly little by little. By using the jig 20 and the rod-like member 21 as described above, the outer surface of the nozzle 12 can be uniformly pushed inward and distorted from directions at equal intervals in the circumferential direction perpendicular to the axis of the nozzle. In the present embodiment, the nozzle has a star-like shape which is pressed from six directions. Although this uses buckling in the circumferential direction for folding, 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 it is In addition, when the storage is advanced after buckling, it is necessary to further push in a part with a small wave number to store the part which is not pushed in, while the circumferential curvature of the pushed part is large when the wave number is large It is necessary to select an appropriate wave number in the middle because the smaller the distortion and the larger the distortion. Further, assuming an actual operation, it is preferable to use an even wave number that can be pushed sequentially from the opposite place, rather than an odd wave number that requires the whole to be pushed equally at the same time in order to balance the forces. These were comprehensively examined, and the six-star shape fold was adopted in this model. However, the shape is not particularly limited as long as the shape when folded is sufficiently small and the distortion does not remain after expansion.
We actually created a scale model of the rocket nozzle and confirmed that it could be folded and unfolded without problems. FIG. 6 is a diagram showing the shape and dimensions of a rocket nozzle model. The rocket nozzle model is assumed to be applied to a real machine, and its 1⁄4 scale has 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. In the drawing, the rolling direction is indicated by an RD (rolling direction), and the rolling perpendicular direction is indicated by an arrow of a TD (transverse direction). With regard to plate thickness, while it is necessary to have a thickness that withstands circumferential stress and axial buckling due to the internal pressure of the nozzle, 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 at the time of storage can be increased. Although the above-mentioned Ti-4.5Al-3V-2Fe-2Mo alloy, which has been subjected to 10.8ks annealing and water cooling at 1073 K, has an elastic recovery strain of about 2%, assuming that it is used, the above-mentioned folded shape When the plate thickness was calculated in consideration of the distortion at the time of storage and the nozzle internal pressure, the required minimum safety factor was secured, and it was 60 μm. This corresponds to 0.25 mm in a real machine.

If it is sufficiently distorted, the knotting cord is wound around the rear end of the nozzle 12 from the gap of the columnar part of the jig 20 one round or several rounds if necessary to connect the both ends. This knotted cord is an example of the distorted shape fixing member of the present invention. Thereby, the distorted state of the nozzle 12 is fixed. In addition, as a knotted string, a plastic tie wrap, a metal wire, etc. can be used.

Also, when the nozzle is deployed, the elastic force of the nozzle 12 itself immediately deploys to the original perfect truncated cone shape, for example, by removing the distorted shape fixing member (in the case of a knotted string, simply cutting). be able to. The time required for the above-described rocket nozzle scale model deployment was less than one second. From this, it is understood that even a rocket nozzle of actual dimensions deploys within 1 second. This is a sufficiently fast time to deploy and eject the nozzle in space.

The deployable structure of the present invention is not limited to the rocket nozzle. For example, the present invention can be applied to a deployment structure such as an antenna for space deployment, which is devised to be distorted, housed small on the ground, transported to space, and deployed there based on its own elasticity.

Further, the expansion method of the present invention is not limited to the method of storing using the jig 20 as described above, and for example, the expanded structure may be distorted using a mold.

Reference Signs List 1 rocket motor 10 nozzle 11 fixed nozzle 12 distortable nozzle 20 jig 21 rod member

Claims

An unfolded structure comprising a super-elastic alloy, wherein the unfolded portion can be accommodated within the elastic deformation range of the super-elastic alloy.
The deployment structure of claim 1, wherein the 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 expanded portion is The deployed structure according to claim 2, wherein the deployed structure is composed of the superelastic alloy.
The diameter of an imaginary circle inscribed in the rear end after distortion is distorted so as to be smaller than the diameter of the circle on the front end before distortion, and the distorted state is fixed by the distortion fixing member. The expanded structure according to claim 2 or 3.
The deployment structure according to claim 4, wherein the distorted shape fixing member is a knotted cord wound around the rear end.
A deployment method for storing or deploying the deployment structure according to any one of claims 1 to 5, comprising:
Distorting the unfolded structure within an elastic deformation range;
Fixing the unfolded structure in the distorted state by a distorted state fixing member;
Deployment method.
The expansion method according to claim 6, wherein the expanded structure in the distorted state is expanded to an original shape by removing the distorted shape fixing member.