CN112855616A - Containing casing and preparation method thereof - Google Patents

Abstract

It is an object of the present invention to provide a containment case that is capable of better containment. Another object of the present invention is to provide a method for preparing a containment case as described above. The casing comprises a composite body formed by winding a strip-shaped preform for at least three turns, and a linear reinforcing material implanted into the preform for at least two turns in the thickness direction of the preform along the circumferential direction of the casing to connect at least one interlayer interface, wherein the depth of implantation of the reinforcing material is less than the thickness of the preform corresponding to the at least one interlayer interface to be connected.

Description

Containing casing and preparation method thereof

Technical Field

The invention relates to a contained casing and a preparation method thereof.

Background

In aeroengines and gas turbines, there are a large number of blades rotating at high speed, and the rotating blades may come off in the event of foreign object impact, process defects, and the like. Therefore, the engine casing is required to have good containment, which means that the casing can ensure that high-speed and high-energy fragments do not penetrate through the casing, thereby causing damage to equipment and personnel. The large unbalanced load of the rotor of the engine after the blades are flied off can cause the engine to generate continuous vibration before stopping, and the casing is still required to maintain certain structural integrity and not be disassembled.

Meanwhile, the engine case is large in size, and the weight of the engine case has a significant influence on the total weight of the engine, so that the efficiency of the engine is influenced. Carbon fiber composite materials are commonly used for low-temperature end casings in new-generation commercial engines. As proposed in patent application publication EP1674244, a fan-containing casing of equal thickness is manufactured using a three-axis woven preform, a resin-added liquid molding process. In EP1674671 a fan-containing casing of variable thickness is proposed, the reinforcing phase of the casing composite core being a circumferentially aligned, multi-layered superimposed braid, the other composite layers being obtained from a helically wound braid. The patent application published under the number US8322971B2 proposes a composite material containing casing, which is obtained by processing a variable thickness fiber preform by a three-dimensional weaving method, then winding the fiber preform on a mandrel in a laminated manner to obtain a casing preform, and then molding the casing by a resin liquid.

Fig. 1 shows a schematic view of an existing aircraft gas turbine engine, which includes a fan section 91, a core engine 93, a low-pressure turbine 94, and a tail cone 95. A fan housing case 910 is provided on the outer peripheral side of the fan section 91 of the engine, and fan blades 92 are provided on the inner side. Fig. 2 shows a schematic cross-sectional view of a prior art containment case comprising a composite body formed by winding a preform 930 at least three turns, it being understood that the preform 930 is wound three turns as in the embodiment shown in fig. 2, and that the preform 930 may be wound more turns in other embodiments than those shown. The preform 930 may be made by three-dimensional weaving of a plurality of layers.

However, the inventors have found that by winding the preform as in fig. 1 to 2 to produce a containment casing, the interface 931 of the different preform layers is joined by the matrix material. Once subjected to a blade-out load, the base material at interface 931 fails under the effect of the interlaminar stresses, causing debonding at the interface and the various layers to begin to separate. After the blade falls off, the engine can generate severe vibration for a period of time, the influence range of interface failure and debonding is continuously enlarged, and finally the rigidity of the casing is seriously reduced, even the casing is disassembled, and great threat is caused to the safety of the human body.

Disclosure of Invention

It is an object of the present invention to provide a containment case that is capable of better containment.

Another object of the present invention is to provide a method for preparing a containment case as described above.

The casing comprises a composite body formed by winding a strip-shaped preform for at least three turns, and a linear reinforcing material implanted into the preform for at least two turns in the thickness direction of the preform along the circumferential direction of the casing to connect at least one interlayer interface, wherein the depth of implantation of the reinforcing material is less than the thickness of the preform corresponding to the at least one interlayer interface to be connected.

In one or more embodiments, the reinforcement material maintains the connection of the at least one interlayer interface through friction of the reinforcement material with the preform.

In one or more embodiments, the casing includes a housing region, a transition region, and an equal-thickness region in the width direction, and at least one set of the reinforcing material is implanted in each of the housing region, the transition region, and the equal-thickness region.

In one or more embodiments, the reinforcement material is implanted into the thickness direction of the preform for every two turns of the preform.

In one or more embodiments, the reinforcement material is implanted in the thickness direction of the preform for two or more turns of the preform.

In one or more embodiments, the reinforcement material is implanted in a thickness direction of the preform for a full number of turns of the preform.

In one or more embodiments, the reinforcing materials implanted in the preform correspond to different rings, and are spaced apart by a distance in a width direction of the casing.

In one or more embodiments, the reinforcing material is distributed along the outer circumference of the casing 360 °.

In one or more embodiments, the reinforcement material is implanted into the preform at the relatively innermost turn to a depth of at least 50% of the thickness of the turn of the preform.

In one or more embodiments, the preform includes an initiation region and a termination region at both ends thereof in a length direction, and an inner wall region, an outer wall region, and a middle region are sequentially disposed from the initiation region to the termination region;

wherein the thickness of the start region and the thickness of the end region are gradually reduced towards the end portion respectively.

In one or more embodiments, the reinforcing material is a continuous yarn made of one or more of carbon fiber, glass fiber, aramid fiber, ultra-high density polyethylene fiber, polyimide fiber, and basalt fiber, or a filament made of steel or titanium.

To achieve the aforementioned another object, a method for manufacturing a containment case includes:

a. winding the preform on a mandrel;

b. after more than one turn of the preform is wound on the mandrel, providing a reinforcing material on the outside of the preform located opposite the outer ring;

c. sequentially implanting the reinforcing material into the prefabricated body along the circumferential direction of the casing by using a thimble mechanism;

d. and pouring the prefabricated body by using resin and curing and forming.

The gain effect of the invention is that: by embedding the reinforcing materials into the prefabricated body containing the casing, the prefabricated bodies of all layers are limited by the reinforcing materials if the prefabricated bodies are separated in a debonding mode, and therefore the containment of the casing is improved.

Drawings

The above and other features, properties and advantages of the present invention will become more apparent from the following description of the embodiments with reference to the accompanying drawings, in which:

FIG. 1 illustrates a schematic view of a prior art aircraft gas turbine engine;

FIG. 2 is a schematic cross-sectional view of a prior art containment case;

FIG. 3 illustrates a cross-sectional view of one embodiment of the present containment case;

FIG. 4 shows a perspective view of the preform in an expanded state;

FIG. 5 shows a cross-sectional view of the first embodiment of the containment case;

FIG. 6 shows a cross-sectional view of a second embodiment of a containment case;

FIG. 7 shows a cross-sectional view of a third embodiment of a containment case;

fig. 8 to 11 show a schematic view of the containment case preparation process.

Detailed Description

The following discloses many different embodiments or examples for implementing the subject technology described. Specific examples of components and arrangements are described below to simplify the present disclosure, but these are merely examples and are not intended to limit the scope of the present disclosure. For example, if a first feature is formed over or on a second feature described later in the specification, this may include embodiments in which the first and second features are formed in direct contact, and may also include embodiments in which additional features are formed between the first and second features, such that the first and second features may not be in direct contact. Additionally, reference numerals and/or letters may be repeated among the various examples throughout this disclosure. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed. Further, when a first element is described as being coupled or coupled to a second element, the description includes embodiments in which the first and second elements are directly coupled or coupled to each other, as well as embodiments in which one or more additional intervening elements are added to indirectly couple or couple the first and second elements to each other.

It should be noted that, where used, the following description of upper, lower, left, right, front, rear, top, bottom, positive, negative, clockwise, and counterclockwise are used for convenience only and do not imply any particular fixed orientation. In fact, they are used to reflect the relative position and/or orientation between the various parts of the object.

For the avoidance of doubt, the reference numerals in the embodiments described later are independent of the labelling systems of figures 1 to 2 of the background art.

Fig. 3 shows a schematic cross-sectional view of one embodiment of the containment casing, and fig. 4 shows a schematic perspective view of the preform in an expanded state. The containment casing 1 is a composite body 10 formed by winding a strip-shaped preform 2 at least three times, the composite body 10 further comprising a reinforcement 3 in the form of a thread, the reinforcement 3 being implanted, for at least two turns of the preform 2, in the thickness direction a of the preform 2 along the casing circumference, so as to connect at least one interlayer interface 20. Wherein, the implantation depth of the reinforcing material 3 is less than the thickness of the prefabricated body corresponding to the connected interlayer interface. It is understood that the interlayer interface 20 refers to the interface sandwiched between adjacent layers of the preform.

The reinforcing material 3 maintains the connection of at least one interlayer interface 20 by friction with the preform 2. When the casing is loaded, the interlayer interface 20 between adjacent preforms 2 is easily debonded due to stress concentration. After the debonding propagation encounters the obstruction of the reinforcing material 3 across the interface, the debonding propagation either propagates along the reinforcing material 3, causing the path of propagation to increase substantially; or the reinforcing material 3 is destroyed and then expanded, increasing the energy consumed by expansion. In addition, the expansion of the interface debonding still needs to overcome the friction force when the reinforcing material 3 is pulled out, and the reinforcing material 3 uses a material with a strong friction effect, so that a large amount of energy is dissipated in the pulling-out process. This means that a greater driving force is required to debond the expansion interface, or in other words the difficulty of debonding expansion increases significantly. Therefore, the interfacial debonding will be suppressed locally, preventing the casing from extensive debonding and the consequent performance degradation. Specifically, in one or more embodiments, the reinforcing material 3 is a continuous yarn made of one or more of carbon fiber, glass fiber, aramid fiber, ultra-high density polyethylene fiber, polyimide fiber, and basalt fiber, and a filament also made of steel or titanium. The reinforcement 3 may also be made of any other fiber or metal that has a strong friction with the preform 2.

With continued reference to fig. 3, in one embodiment of the containment case, the case 1 includes a containment region 11, a transition region 12, and an equal thickness region 13 in the width direction b, and at least one set of reinforcing materials 3 is implanted into the containment region 11, the transition region 12, and the equal thickness region 13, respectively. Specifically, as shown in fig. 4, the preform 2 is flattened to be approximately rectangular, and the width thereof is equal to or greater than the width of the casing 1. The width direction includes a region 21 corresponding to the casing accommodating region 11, a region 22 corresponding to the transition region 12, and a region 23 corresponding to the equal-thickness region 13. The equal-thickness area 13 comprises an area corresponding to a flange 14 of the casing, a flanging is formed at the flange 14 in an area 23 corresponding to the equal-thickness area 13 in the prefabricated body 2, the containing casing 1 is connected with an engine through bolts, the periphery of the containing casing is not prone to layering due to the fastening effect of the bolts, a part of the casing outside the fastening effect area of the bolts still exists, and the containing capacity of the casing is further improved by respectively implanting reinforcing materials 3 into the areas. It is understood that the direction of the reinforcing material 3 implanted at the corresponding casing flange 14 is the horizontal direction shown in the drawing. Wherein the width direction of the preform 2 is the weaving weft direction.

Please continue to refer to fig. 3. The preform 2 comprises in the longitudinal direction a starting zone 24 and a terminating zone 25, and further comprises an inner wall zone 26, which corresponds to the inner wall of the casing, an outer wall zone 27, which corresponds to the outer wall of the casing, and an intermediate zone 28. The starting zone 24 and the ending zone 25 are located at two ends of the preform 2, the respective lengths are not less than the arc length of 10 degrees of the outer diameter of the casing, the thickness is gradually reduced towards the end part, and the step height of the end part is reduced, so that the possibility of interface failure caused by stress concentration at the position is reduced. The inner wall area 26, the middle area 28 and the outer wall area 27 are arranged in sequence from the starting area 24 to the ending area 25, and the length of the preform 2 is such that the number of turns of winding of the casing preform is not less than 3 and not more than 20. For softer preform materials, reducing the number of turns can improve production efficiency. But the prefabricated body with higher rigidity needs to increase the winding number, so that the prefabricated body area 23 corresponding to the equal-thickness area 13 still has certain deformability, and the prefabricated body can be turned over to form a flange edge. But also needs to avoid too many winding turns and too thin thickness of the single-layer preform, and to avoid too many resin-rich areas on the surface of the preform after molding. The thickness of each area of the prefabricated body is changed according to the requirement by adjusting the layer number of the yarns during weaving, so that the imitated prefabricated body imitating the contour and the thickness distribution of the casing is realized. It is to be understood that fig. 3 is only a schematic representation, and the lengths of the start zone 24, the end zone 25, the inner wall zone 26, the middle zone 28, and the outer wall zone 27 shown in the figure are merely examples, and the actual lengths thereof should not be limited only by those shown in the figure.

In one embodiment of the containment case, the reinforcement material 3 is distributed 360 ° around the circumference of the case, further enhancing the containment of the case as a whole.

In one embodiment of the containment case, the reinforcement 3 is embedded in the preform of the relatively innermost turn to a depth of at least 50% of the thickness of the preform of the turn, so as to ensure that the reinforcement 3 is embedded in the interlayer interface 20 to be connected to a sufficient depth that it will dissipate a great deal of energy during extraction, thus improving the containment of the case.

The following description is directed to a specific implantation of the reinforcing material 3 in various embodiments that house the casing 1.

Implementation mode one

Fig. 5 shows a schematic cross-sectional view of a first embodiment of the containment case, wherein the reinforcement material 3 'is implanted for every two turns of the preform 2' in its thickness direction. In particular, the second set of reinforcing materials 3a 'is implanted in two adjacent turns of preforms 2 a' and 2b 'located on opposite outer sides, and the first set of reinforcing materials 3 b' is implanted in two adjacent turns of preforms 2b 'and 2 c' located on opposite inner sides. Wherein, the second group of reinforcing materials 3a 'and the first group of reinforcing materials 3 b' implanted corresponding to different rings are respectively separated from each other by a distance along the width direction of the casing (i.e. the direction perpendicular to the paper surface) so as to avoid the two groups of reinforcing materials 3a 'and 3 b' from overlapping. The depth h1 of implantation of the reinforcement 3 ' is less than the thickness b1 of the preforms 2a ' and 2b ' corresponding to the interface between the layers to be joined. In some embodiments other than those illustrated, the reinforcing material may be in multiple groups.

Second embodiment

Fig. 6 shows a schematic cross-sectional view of a second embodiment of the containment case, in which the reinforcing material 3 "is implanted in the thickness direction of the preform 2" for every three turns. In particular, the second set of reinforcing materials 3a "is implanted in the three adjacent turns of preforms 2 a", 2b ", 2 c" situated on the opposite outer side, and the first set of reinforcing materials 3b "is implanted in the three adjacent turns of preforms 2 c", 2d ", 2 e" situated on the opposite inner side. Wherein, the second group of reinforcing materials 3a "and the first group of reinforcing materials 3 b" implanted corresponding to different rings are respectively separated from each other by a distance along the width direction of the casing (i.e. the direction perpendicular to the paper surface) so as to avoid the two groups of reinforcing materials 3a "and 3 b" from overlapping. The depth of implantation h2 of the reinforcement 3 "is less than the thickness b2 of the preforms 2 a", 2b ", 2 c" corresponding to the interface between the layers to be joined. In some embodiments other than those shown, the reinforcement material may be in multiple groups, with each group having more than three turns of reinforcement material implanted therein.

Third embodiment

Fig. 7 shows a schematic cross-sectional view of a third embodiment of the containment case, in which the reinforcing material 3 "'is implanted in its thickness direction for all turns of the preform 2"'. Specifically, the number of turns of the preform 2 '"may be three or more as shown, and the preform 2'" is passed through the interlaminar interface formed between all the turns of the preform and implanted into the innermost turn of the preform. The depth of implantation h3 of the reinforcing material 3 "'is less than the thickness b3 of the preform 2"' corresponding to the interface between the layers being joined.

The following description is directed to the method for manufacturing a containment case according to one or more of the above embodiments.

Fig. 8 to 11 show a schematic view of the process for preparing the containment case.

Step a: winding the preform on a mandrel.

As shown in fig. 8, the preform 2 is wound on the core mold 50. The core mold 50 is rigid and has a hollow cylindrical shape, and has a step on its outer surface which matches the starting region 24 of the preform 2. The core is connected to a drive mechanism at the hollowed portion 51 to allow the core to rotate about the axis of rotation. The outer wall 52 of the core is thick enough to ensure the rigidity of the core. Starting from the starting zone 24, the core mold 50 is rotated to wind the preform 2 onto the core mold 50. During winding, the part of the preform 2 corresponding to the flange in the equal-thickness zone 23 is turned over.

Step b: after the preform has been wound more than one turn around the mandrel, reinforcement is provided on the outside of the preform opposite the outer ring.

Specifically, the method comprises the following steps: after the preform 2 is wound one turn and covers the initiation area 24 as shown in fig. 8, the reinforcing material 3 is disposed from the outside of the preform 2 covering the initiation area 24. The preform wound this turn corresponds to the inner wall zone 26 in the preform.

Step c: and sequentially implanting the reinforcing material into the prefabricated body ring along the circumferential direction of the casing by using a thimble mechanism.

Specifically, the method comprises the following steps: as shown in fig. 9, in the area where the start area 24 is stacked with the first turn of the preform, a group of reinforcing materials 3 are sequentially inserted into the casing preform 2 at equal intervals along the circumferential direction of the casing using an ejector mechanism. The distance between the inserted individual reinforcing materials 3 is greater than 5mm and less than 200mm, and the insertion range does not exceed the stacked preform 2. In the process of inserting, part of the reinforcing material 3 is sent into the prefabricated body 2, and when the thimble mechanism is pulled out, the reinforcing material 3 is left in the prefabricated body 2, so that the reinforcing material is implanted. Further, since the reinforcing material 3 is in a linear shape, a portion for connecting the reinforcing materials is left outside the preform. The implantation process is repeated, so that the width direction of the casing corresponds to the areas of the containing area 11, the transition area 12 and the equal-thickness area 13, and at least one group of reinforcing materials 3 are implanted into each area. The region of equal thickness 13 corresponding to the flange edge is now not implanted with reinforcing material. The implantation is such that the reinforcement 3 extends completely through the first winding of the preform and is embedded to a certain length in the starting zone 24. This length is at least equal to the lesser of 70% of the minimum thickness and 2mm to avoid the structure of the thimble colliding with the core die 50. Wherein, at the thicker position of the initial region or the position where the thimble is not easy to collide, the implantation depth should be at least 70% of the thickness of the position, and at this time, the implantation of the reinforcing material 3 is completed for the portion of the initial region 24.

After the preform 2 is wound more turns outside the core mold 50 as shown in fig. 10, the reinforcing material 3 is continuously implanted as follows:

for the first embodiment shown in fig. 5, after the reinforcement material 3 is implanted in the initial region 24, the preform 2 is wound until a complete turn is made, at which time a portion of the intermediate region 28 of the preform is wound onto the mandrel 50 and the first turn of the preform. Then, the thimble mechanism is continuously used to implant a group of reinforcing materials 3' equidistantly in the 360-degree range of the circumferential direction of the casing. The depth of implantation should penetrate the freshly wound preform and be at least 50% of the thickness of the first turn of the preform. The distance between the implanted single reinforcing materials 3' is more than 10mm and less than 200 mm. The implantation process is repeated, so that the width direction of the casing corresponds to the areas of the containing area 11, the transition area 12 and the equal-thickness area 13, and at least one group of reinforcing materials 3' are implanted into each area. The spacing of each set of reinforcing material 3' should be greater than 10mm and less than 200mm, with the actual distance determined by the casing design.

In the second embodiment shown in fig. 6, after the reinforcing material 3 is implanted in the initial region 24, the reinforcing material 3 ″ is implanted by winding a number of more integer turns. In doing so, it should be ensured that the implanted reinforcement material 3 "extends through all of the wound preforms and at least through 50% of the thickness of the preform relative to the innermost turn. For example, after winding two full turns of the preform as shown in the figure, a first set of reinforcing materials 3b "is implanted equidistantly over 360 ° of the circumference of the casing using a thimble mechanism. Two more complete turns of the preform are then wound, followed by implantation of a second set of reinforcing materials 3a ". The above operation is repeated until a sufficient number of turns of reinforcing material 3 "have been wound.

In the third embodiment shown in fig. 7, after the reinforcing material 3 is implanted in the initial region 24 until the last preform 2 "'is completely wound, the reinforcing material 3"' is implanted so as to penetrate through the opposite innermost preform 2 "'and reach at least 50% of the thickness of the pair of innermost preforms 2"'.

As in the previous embodiments one to three, after winding a single layer or several layers, the reinforcement material 3 is implanted until the winding of the last turn of preform 2 and the reinforcement material implantation is completed. The reinforcing materials 3 passing through the different layers of the preform should be staggered by at least 20mm to avoid mutual influence.

Subsequently, as shown in fig. 11, the winding of the termination region 24 is completed, and the reinforcing material 3 is implanted in the region where the termination region 24 overlaps with the last turn of the preform 3. The implantation should be such that the reinforcement material 3 extends completely through the preform in the termination zone 24 and at least up to 50% of the thickness of the last ring of the preform 3.

Subsequently, the flange is bolted in the region other than the flange. The reinforcement material 3 is implanted equally in the thickness direction of the flange edge, the implantation being such that the reinforcement material 3 penetrates all the preform layers 2 until at least 50% of the thickness of the last ring of the preform.

Step d: and pouring the prefabricated body by using resin and curing and forming.

Specifically, a rigid outer mold or a flexible material is used to wrap the outer surface of the wound casing preform 2, a cavity required by liquid molding is formed by the rigid outer mold or the flexible material and the core mold 50, liquid resin is introduced into the cavity by using a proper liquid molding process, the resin is cured by adopting a heating, pressurizing, vacuumizing or other proper process methods, and the cured casing is demolded to complete subsequent processing.

Although the present invention has been disclosed in terms of the preferred embodiment, it is not intended to limit the invention, and variations and modifications may be made by one skilled in the art without departing from the spirit and scope of the invention. Therefore, any modification, equivalent change and modification of the above embodiments according to the technical essence of the present invention are within the protection scope defined by the claims of the present invention, unless the technical essence of the present invention departs from the content of the present invention.

Claims (12)

1. A containment casing comprising a composite body formed by winding a strip-shaped preform through at least three turns, characterized in that said composite body further comprises a reinforcement in the form of a thread implanted along the casing circumference in the direction of the thickness of the preform for at least two turns so as to connect at least one interlaminar interface, said reinforcement being implanted to a depth less than the thickness of the preform corresponding to said at least one interlaminar interface to be connected.

2. A containment case according to claim 1, wherein said reinforcing material maintains the connection of said at least one layer interface by friction of the reinforcing material with the preform.

3. A containment case according to claim 1, wherein the case includes, in a width direction, a containment region, a transition region, and a uniform thickness region, at least one set of said reinforcement material being implanted in each of said containment region, said transition region, and said uniform thickness region.

4. A containment casing according to claim 1, wherein said reinforcing material is implanted into the thickness of the preform for every two turns of said preform.

5. A containment casing according to claim 1, wherein said reinforcing material is embedded in the thickness direction of the preform for more than two turns of said preform.

6. A containment casing according to claim 5, wherein said reinforcing material is implanted in the thickness direction of the preform for a full number of turns of said preform.

7. A containment case according to claim 1, wherein said reinforcing material implanted in said preform for different rings is spaced apart along the width of the case.

8. A containment case according to claim 1, wherein said reinforcing material is distributed along 360 ° of the outer circumference of the case.

9. A containment case according to claim 1, wherein said reinforcing material is embedded in said preform for the innermost turn to a depth of at least 50% of the thickness of the preform for that turn.

10. A containment casing according to claim 1, wherein said preform includes, in the lengthwise direction, an initiation region and a termination region at each end thereof, an inner wall region, an outer wall region and an intermediate region being disposed in that order from said initiation region to said termination region;

wherein the thickness of the start region and the thickness of the end region are gradually reduced towards the end portion respectively.

11. A containment case according to claim 1, wherein said reinforcing material is a continuous yarn made of one or more of carbon fiber, glass fiber, aramid fiber, ultra-high density polyethylene fiber, polyimide fiber, basalt fiber, or a filament made of steel, titanium.

12. A method of making a containment casing according to any one of claims 1 to 11, including:

a. winding the preform on a mandrel;

b. after more than one turn of the preform is wound on the mandrel, providing a reinforcing material on the outside of the preform located opposite the outer ring;

c. sequentially implanting the reinforcing material into the prefabricated body along the circumferential direction of the casing by using a thimble mechanism;

d. and pouring the prefabricated body by using resin and curing and forming.

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