GB2128261A

GB2128261A - Honeycomb structure, e.g. for a turbine shroud

Info

Publication number: GB2128261A
Application number: GB8326139A
Authority: GB
Inventors: John R Plautz
Original assignee: Individual
Current assignee: Individual
Priority date: 1982-09-30
Filing date: 1983-09-29
Publication date: 1984-04-26
Also published as: GB2128261B; GB8326139D0

Abstract

Means are provided for mechanically locking an abradable matrix material in the honeycomb structure. The mechanical lock may comprise split and deformed portions 18 of the honeycomb structure extending into adjacent honeycomb cells to engage the abrasive matrix material. The splitting and deforming may be accomplished during the manufacture of the honeycomb structure so that it engages the abradable matrix material prior to setting thereof in the honeycomb material. Alternatively, longitudinally extending members forming the honeycomb structure may be transversely deformed along part or all of their length, nested and secured together to provide mechanical locking for abradable matrix material placed in the honeycomb structure. <IMAGE>

Description

SPECIFICATION Turbine shroud honeycomb matrix mechanical locking structure and method The invention relates to turbine engine shrouds or the like and refers more specifically to a mechanical locking structure for and method of securing an abradable matrix material in a honeycomb structure on a turbine engine shroud or the like.

In the past, bonding of an abradable matrix material to honeycomb structure on turbine engine shrouds or the like, has been accomplished during sintering of the matrix material. The mechanical bond provided between the matrix material and honeycomb structure has in the past been determined by the physical number of contacts between the honeycomb structure and one component of the sintered matrix material.

Approximately 65 bonds per inch between nickel coated aluminum abrasive powder in the sintered matrix material and steel honeycomb structure has been considered adequate to prevent the sintered matrix material from working loose from the honeycomb structure cells in which it is deposited on the shroud.

Thus, in the construction of such shrouds or shroud sections, since the shrouds are normally constructed in sections, the sintering of the abradable material has been necessarily carefully controlled, and samples taken thereof which have been polished and the bonds between the honeycomb structure and the sintered abradable powder laboriously counted as a test of the quality of the shrouds produced. Such testing requires special equipment is time consuming and expensive. Further, the adequacy of the bonding of the matrix material to the honeycomb structure is not well established by such tests.

The structure of the invention is mechanical locking or detent means between a honeycomb structure and matrix material positioned therein.

More specifically in one embodiment, the structure of the invention includes split and deformed honeycomb cell wall portions providing transverse mechanical extensions act as detents in the honeycomb structure to lock the matrix within the honeycomb structure.

In a preferred embodiment of the invention, detent means for locking the matrix within the honeycomb structure is provided by longitudinally deformed central portions of elongated members forming the honeycomb structure which elongated members are secured together with the deformed portions nesting to form the honeycomb structure.

The method of the invention comprises providing mechanical locking means between the honeycomb structure of a shroud for a turbine engine or the like and an abradable matrix within the honeycomb structure. In accordance with the method of the invention, the locking means is provided by splitting and/or deforming some of the walls of selected cells of the honeycomb structure during manufacturing of the honeycomb structure.

The invention will now be described in greater detail, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a perspective view of a turbine shroud section including mechanical locking means between the abradable matrix material and honeycomb structure thereof in accordance with the structure of the invention constructed in accordance with the method of the invention.

Figure 2 is an enlarged transverse section view of the shroud section illustrated in Figure 1, taken substantially on the line 2-2 in Figure 1.

Figure 3 is an enlarged plan view of a portion of the honeycomb structure of the shroud section of Figures 1 and 2 showing one of the honeycomb cells split and deformed to provide a mechanical lock between the honeycomb structure and matrix material of the shroud section.

Figure 4 is a further enlarged plan view of the one split and deformed honeycomb cell of the honeycomb structure illustrated in Figure 3.

Figure 5 is a section view of the split and deformed honeycomb cell illustrated in Figure 4, taken on the line 5-5 in Figure 4.

Figure 6 is a partial elevational view of the split and deformed honeycomb cell illustrated in Figure 4, taken substantially in the direction of arrow 6 in Figure 4.

Figure 7 is an enlarged plan view of a portion of a honeycomb cell simiiar to Figure 4 split and deformed in a different manner to provide a mechanical lock between the honeycomb structure and abradable material.

Figure 8 is a section view of the split and deformed honeycomb cell illustrated in Figure 7, taken on the line 8-8 in Figure 7.

Figure 9 is a partial elevation view of the split and deformed honeycomb cell illustrated in Figure 7, taken in the direction of arrow 9 in Figure 7.

Figure 10 is another plan view of a portion of another embodiment of the honeycomb structure of the shroud section of Figures 1 and 2 showing the members of the honeycomb cell deformed longitudinally and nested to provide a mechanical lock between the honeycomb structure and matrix material of the shroud section.

Figure 11 is an enlarged section view of the honeycomb structure shown in Figure 10 taken substantially on the line 11-11 in Figure 10.

Figure 1 2 is an enlarged section view of the honeycomb structure shown in Figure 10 taken substantially on line 12-12 in Figure 10.

As shown best in Figure 1, the turbine engine shroud section 10 includes an arcuate base 12, honeycomb structure 14 secured to the base 12, and an abradable matrix material 1 6 positioned within the honeycomb structure.

Mechanical locking or detent means 18 is shown operable between the honeycomb structure 14 and abradable matrix 16 in accordance with the invention. In use, the locking means 1 8 prevents the abradable matrix material 1 6 from separating from the honeycomb structure 14.

More specifically, the base 12 is an arcuate steel member having a convex side 20 and a concave side 22. The base 12 has a dovetail cross section portion 24 best shown in Figure 2 which is utilized to secure the base 12 to the casing of a jet engine or the like.

The honeycomb structure 14 as best shown in Figure 3 is constructed of a plurality of separate strips such as strips 26, 28, 30 and 32 bent as shown in Figure 3 to form one half of six-sided honeycomb cells on opposite sides thereof alternately along its length. The strips 26 and 28, 28 and 30 and 30 and 32 are secured together as by welding or the like at junctions such as junctions 34, 35 and 37 respectively to provide the basic honeycomb structure 14.

The honeycomb structure 14 which is thus separately constructed is secured to the concave surface 22 of the base 12 by convenient means such as welding, brazing, or the like.

The abradable material 1 6 is positioned in the individual cells of honeycomb structure 14 such as cell 36 and the shroud section 10 having the abradable material in the cells of the honeycomb structure is sintered at for example 1900 or 1950 .

The abradable material 16 may for example be a blend of nickel and aluminum powder consisting of 75% nickel coated aluminum powder and 25% by weight nickel powder. The nickel aluminum and nickel powder may be mixed with an organic binder comprising two grams of ammoniumalgonate to 100 millilitres of distilled water. The powder and binder are mixed to a pliable consistency.

When such abradable material 1 6 is placed in the honeycomb structure 14 and sintered, it expands so that nickel coated aluminum particles engage the walls of the honeycomb structure.

Where there is no visible line between the nickel coated aluminum particles and the honeycomb structure there is said to be a bond between the abradable matrix material 1 6 and the honeycomb structure. Approximately 65 bonds per inch of honeycomb structure has in the past been determined to provide an acceptable bond between the matrix material and the honeycomb structure.

According to one embodiment of the present invention, however, the separate honeycomb strips such as strips 30 and 32 for example of the honeycomb material of Figure 3 are selectively split and deformed prior to their being assembled in the honeycomb structure and welded together.

As shown best in Figures 3 through 6, the splitting and deforming contemplated provides transversely extending detents or locking means 18, for positively mechanically locking the abrasive matrix material 1 6 into the individual cells such as cell 36 of the honeycomb structure 14. Thus, the matrix material 1 6 is positively prevented from separating from the honeycomb structure 14.

As shown in Figures 3 through 6, the locking means 1 8 is accomplished by a diamond shaped splitting and deforming of one or more of the six side walls of a cell 36 of the honeycomb material 14. The splitting and deforming illustrated in Figure 4 is substantially diamond shaped as shown in Figure 6 with the honeycomb material split at 38 substantially parallel to the concave surface 22 of the base 12.

As shown best in Figure 5, the upper and lower portions of the split side walls are deformed in opposite directions into the individual cells of the honeycomb material 14 to which they are adjacent. As shown in Figure 5, the upper portion 42 and the lower portion 44 of the split and deformed portion of the side wall 40 of the honeycomb structure 14 have their maximum deformation centrally of the split 38.

The general configuration of the splitting and deforming is then a diamond shape and provides a diamond shaped structure producing mechanical locking in both adjacent honeycomb cells that have the common side wall 40.

As in the past, with the honeycomb structure 14 constructed with the split and deformed portions therein as shown in Figure 3, the honeycomb structure 14 is secured to the base 12 and the abrasive matrix material 16 is placed in the individual cells of the honeycomb structure-14.

The shroud section 10 is then sintered to provide the previous bonding between the particles-of the abradable matrix material 16 and the honeycomb structure 1 4 and base 12. However, in accordance with the invention there is also provided the positive mechanical locking between the individual cells 36 and abradable matrix by the locking means 1 8 provided by the split and deformed side walls such as side wall 40: Modifications of the mechanical locking means shown in Figures 4 through 6is contempiated.

Thus, in Figures 7, 8 and 9, a generally X-shaped split and deformed configuration is utilized. In such configuration, a side wall 46 of an individual cell 47 of a honeycomb structure is split at 48 and 50 and the upper and lower ends 52 and 54 of the split and deformed portion of the side wall 46 are deformed to have their maximum dimension again centrally of the splits 48 and 50, all as shown in Figures 7, 8 and 9.

The X-shaped split and deformed structure shown in Figures 7, 8 and 9 again provides mechanical detents or locking means to prevent separation of the abradable matrix material from the honeycomb structure.

In the preferred embodiment of the invention, illustrated in Figures 10 through 12, the individual elongated members 60, 62, 64 and 66 of the honeycomb structure 68 are deformed longitudinally as best shown in Figure 12 over their entire length. The individual honeycomb members such as 60, 62, 64 and 66 are then positioned together with the longitudinally extending deformations therein nested as shown best in Figure 11 and are welded together as before.

The honeycomb structure 68 is then utilized to construct a shroud such as shroud 10 illustrated in Figure 1 as before. In this embodiment of the honeycomb structure, the longitudinally extending deformations in the individual honeycomb members 60, 62, 64 and 66 provide areas such as area 72 and projections such as the projections 74 for receiving the matrix mix and/or extending into the matrix mix to again provide detent means to prevent the matrix mix from becoming loose from the shroud constructed with the honeycomb structure 68, in addition to the bonding of the matrix mix to the honeycomb structure as before.

The honeycomb structure 68 is particularly advantageous in that no cutting of the individual honeycomb members is required whereby heat transfer through the honeycomb structure 68 is not impeded. Thus, in the embodiment of the invention shown in Figures 10, 11 and 12, less than all the honeycomb walls may be deformed as desired.

While multiple embodiments and modifications of the present invention has been considered in detail, it will be understood that other embodiments and modifications thereof are contemplated. lt is the intention to include all such embodiments and modifications as am defined by the appended claims with the scope of the invention.

Claims

1. A shroud section for a turbine engine or the like comprising an arcuate base member having concave and convex sides and including means for securing the shroud section to a turbine engine casing, a honeycomb structure secured to the base on the concave side thereof, a matrix of abradable material within the honeycomb structure, and mechanical locking means operable between the honeycomb structure and abradable matrix- materia for securing the matrix material within the the-hone Vcomb structure.

2. Structure as set forth in claim 1 wherein the matrix material is abradable.

3. Structure as set forth in claim 1, wherein the mechanical locking means comprises deformed portions of the walls of the cells extending transversely into the abradable matrix material.

4. Structure as set forth in claim 3, wherein the deformed portions of the honeycomb structure are deformed in a diamond configuration and the center of the diamond configuration is split substantially parallel to the concave surface of the base and the upper and lower portions of the diamond shaped deformed portion of the honeycomb material extend in opposite directions into adjacent cells with their maximum deformation appearing at the split center of the diamond configuration.

5. Structure as set forth in claim 3, wherein the deformed portions of the honeycomb structure are deformed in an X configuration and the honeycomb structure is split at the bottom and top of the X configuration substantially parallel to the concave surface of the base with the greatest deformation of the deformed material being in opposite directions centrally of the bottom and top of the X configuration.

6. Structure as set forth in claim 3, wherein the honeycomb structure is constructed of a plurality of elongated members having inner and outer edges deformed and secured together wherein the elongated members are deformed transversely longitudinally thereof between the inner and outer edges thereof to provide the portions extending to the abradable matrix material.

7. Structure as set forth in claim 6, wherein the elongated members are deformed transversely longitudinally thereof between the inner arid outer edges thereof over substantially the entire length thereof.

8. Structure as set forth in claim 6, wherein at least part of the portions of the elongated members which are deformed transversely longitudinally are nested before the elongated members are secured together.

9. Honeycomb structure including a plurality of individual cells having a matrix of settable material within the individual cells thereof and mechanical locking means operable between the individual cells of the honeycomb structure including.a portion of at least some of the walls of the cells being-deformed transversely only between and in spaced relation to the ends of the cells so as to extend into the celts.

10. A shroud section for a turbine engine comprising an arcuate base member having a generally T-shape cross section on the convex side thereof with the cross portion of the cross section forming the outermost convex surfaces for securing the shroud section to a turbine engine casing, a honeycomb structure secured to the concave side of the shroud section including a plurality of individual cells constructed of a plurality of separate metal bands bent to form half of six-wálled honeycomb cells alternately on opposite sides thereof .welded together to form six-walled honeycomb structure, a matrix of material within the individual cells of the honeycomb structure and mechanical means for securing the matrix material to the honeycomb structure including portions of at least some of the walls of the cells being deformed transversely only between and in spaced relation to the ends of the cells so as to extend into the cells.

11. The method of constructing a shroud section for a turbine engine or the like comprising forming an arcuate metal base, securing a honeycomb structure on the concave side of the base, placing a settable matrix material into the individual cells of the honeycomb structure and mechanically bonding the matrix material to the honeycomb material.

12. The method as set forth in claim 11, wherein the mechanical bonding step comprises splitting and deforming the honeycomb structure as it is produced to provide portions thereof which extend into the individual cells of the honeycomb structure to engage the matrix material therein prior to its setting.

1 3. The method as set forth in claim 12, wherein the splitting and deforming is accomplished in a diamond configuration with the center of the diamond cut and with the material on each side of the center of the diamond extended in opposite directions into the adjacent honeycomb cells.

14. The method as set forth in claim 12, wherein the splitting and deforming is in an X configuration and the ends of the X configuration are slit and extended in opposite directions into the adjacent honeycomb cells.

15. The method as set forth in claim 11, wherein the honeycomb structure is formed of a plurality of elongated members off-set transversely and secured together and mechanical locking is accomplished by transversely deforming longitudinally extending portions of the elongated members and nesting said deformed portions.

16. A turbine engine shroud section substantially as hereinbefore described with reference to, and as illustrated, by the accompanying drawings.

17. A method of constructing a turbine engine shroud section substantially as hereinbefore described with reference to the accompanying drawings.