摘要:
Methodology and tooling arrangements for increasing interlaminar shear strength in a ceramic matrix composite (CMC) structure are provided. The CMC structure may be formed by a plurality of layers of ceramic fibers disposed between a top surface and a bottom surface of the composite structure. A plurality of surface recesses are formed on the surfaces of the structure. For example, each of the surfaces of the composite structure may be urged against corresponding top and bottom surfaces of a tool having a plurality of asperities. The plurality of surface recesses causes an out-of-plane sub-surface fiber displacement along an entire thickness of the structure, and the sub-surface fiber displacement is arranged to increase an interlaminar shear strength of the structure.
摘要:
The interlocking of two or more sections via the insertion of one or more out-of-plane features in one section or combination of sections through a void in one or more a complementary sections can result in a reinforced ceramic matrix composite article upon securing of the sections. The sections can be secured by friction between two tightly matched sections or by the use of a pin, hook, or clamp. The sections can be constructed from one or more CMC laminate sheets. The out-of-plane feature can be a loop or a flange and the void can be an orifice or a matched loop in the complementary sheet. The securing of the sections can result in a CMC article where the delamination between sheets is inhibited.
摘要:
A method of manufacturing a hybrid structure (100) having a layer of CMC material (28) defining an interior passageway (24) and a layer of ceramic insulating material (18) lining the passageway. The method includes the step of casting the insulating material to a first thickness required for effective casting but in excess of a desired second thickness for use of the hybrid structure. An inner mold (14) defining a net shape desired for the passageway remains in place after the casting step to mechanically support the insulating material during a machining process used to reduce the thickness of the insulating material from the as-cast first thickness to the desired second thickness. The inner mold also provides support as the CMC material is deposited onto the insulating material. The inner mold may include a fugitive material portion (20) to facilitate its removal after the CMC material is formed.
摘要:
A hybrid ceramic structure and a method for protecting the hybrid ceramic structure from moisture attack in a high temperature combustion environment are provided. The structure includes a ceramic matrix composite (CMC) substrate (12). A thermal insulation material (14) is disposed on the substrate. A vapor resistant material (20) is applied through at least one surface of the hybrid ceramic structure while the hybrid ceramic structure is in a bisque condition that provides a degree of porosity to the hybrid ceramic structure so that the vapor resistant material is infiltrated through interstices available within a thickness of the hybrid ceramic structure.
摘要:
A hybrid ceramic structure and a method for protecting the hybrid ceramic structure from moisture attack in a high temperature combustion environment are provided. The structure includes a ceramic matrix composite (CMC) substrate (12). A thermal insulation material (14) is disposed on the substrate. A vapor resistant material (20) is applied through at least one surface of the hybrid ceramic structure while the hybrid ceramic structure is in a bisque condition that provides a degree of porosity to the hybrid ceramic structure so that the vapor resistant material is infiltrated through interstices available within a thickness of the hybrid ceramic structure.
摘要:
A ceramic matrix composite (CMC) structure 12 includes a plurality of layers (e.g., 16, 18, 20) of ceramic fibers. The CMC structure 12 further includes a plurality of spaced apart objects 22 on at least some of the plurality of layers along a thickness of the composite structure. The inclusion of the objects introduces an out-of-plane fiber displacement arranged to increase an interlaminar shear strength of the structure.
摘要:
A ceramic matrix composite (CMC) structure (50) with first (26) and second (28) CMC walls joined at an intersection (34) containing continuous fibers (53). A gusset (52) is formed in the intersection by an inward bending of some or all ceramic fibers (53) of the intersection, resulting in a diagonal brace between the first and second CMC walls. This creates a depression (54) or void (59) in the intersection. One or more ceramic reinforcement devices fill or span the depression to prevent distortion of the gusset. The reinforcement devices may include a ceramic filler (60) or core (61), a CMC rod or cord (56), and a CMC tape (62). The ceramic filler (60) may be continuous with a ceramic insulation layer (36) on an outer surface of the first CMC wall.
摘要:
A stack of substantially parallel ceramic plates (22) separated and interconnected by ceramic spacers (26, 27) forming a seal structure (20) with a length (L), a width (W), and a thickness (T). The spacers are narrower in width than the plates, and may be laterally offset from spacers in adjacent rows to form a space (28) in a row that aligns with a spacer in another adjacent row. An adjacent plate bends into the space when the seal structure is compressed in thickness. The spacers may have gaps (60, 62) forming a stepped or labyrinthine cooling flow path (66) within the seal structure. The spacers of each row may vary in lateral separation, thus providing a range of compressibility that varies along the width of the seal structure.
摘要:
Structural arrangements and methodology are provided for strengthening a bond between corresponding surfaces of a thermally insulating ceramic coating (14) and a ceramic matrix composite substrate (12). A subsurface inclusion of spheroid objects allows to influence a texture of an outer surface of the CMC substrate to enhance the bonding characteristics between the corresponding surfaces.
摘要:
A ceramic matrix composite (CMC) structure and methods of fabricating such structure are disclosed. In one example, the surface of a CMC substrate (12) is urged against a surface of a tool having blunt teeth. The blunt teeth can form surface indents that can serve as a first bond-enhancing arrangement between the surface of the substrate and a corresponding boundary of a thermally-insulating coating (14). In another example, sharp teeth can form surface indents and also penetrate through the surface of the substrate to cut some of the fibers beneath the surface of the substrate into split fiber segments, and a portion of the split fiber segments can protrude above the surface of the substrate. The protruding fiber segments can serve as a second bond-enhancing arrangement between the surface of the substrate and the corresponding boundary of the coating.