Patent Application
20120202003
This disclosure relates to a method for use in the manufacturing of a fiber reinforced composite article.
Composite materials are used as a replacement to heavier, metallic alloys. The use of composite materials, especially oriented fiber composites, is limited though by the design requirements of the end use application and also the available composite processing techniques. For instance, the manufacturing of an oriented fiber composite typically involves laying-up sheets or layers of dry or pre-impregnated fibers, consolidating the stack of laid-up sheets and impregnating the fibers with the matrix material. Thus, the shape of the article and orientation of the fibers within the article is limited by how the fiber layers can be stacked in the lay-up process. Furthermore, the handling of the fiber sheets and laid-up stack during processing can disturb or damage the fibers to the detriment of the final article.
The various features and advantages of the disclosed examples will become apparent to those skilled in the art from the following detailed description. The drawings that accompany the detailed description can be briefly described as follows.
As illustrated, the composite article 20 includes first fibers 26a that generally extend circumferentially around the central axis 24 and second fibers 26b (reinforcing members) that extend radially with regard to the central axis 24 to form a wall. There are interstitial areas 27 between the first fibers 26a. The first fibers 26a are arranged in fiber sheets or layers 28 that extend circumferentially around the central axis 24. The second fibers 26b extend radially through the fiber layers 28 in at least a portion of the interstitial areas 27, such that the all of the first fiber 26a are intact with regard to any fiber fractures. Additionally, the first fibers 26a may be intact with regard to fiber orientation such that the second fibers 26b do not displace the first fibers 26a to cause bends or deviations on orientation to accommodate the second fibers 26b in the interstitial areas 27. The first fibers 26a and the second fibers 26b are shown schematically and the spacing between the fibers and layers is exaggerated in the drawings for the purpose of visual clarity.
The first fibers 26a and the second fibers 26b in the composite article 20 are dispersed within a matrix 30. The matrix 30, the first fibers 26 and the second fibers 26b form the body of the composite article 20.
The materials of the first fibers 26a, the second fibers 26b and the matrix 30 are selected based upon the desired properties of the composite article 20. In some examples, the composite article 20 may be a polymer matrix composite. Alternatively, the composite article 20 may be a ceramic matrix composite. In either case, the fibers may be carbon fibers or ceramic fibers, but the use of other kinds of fibers is also contemplated. The ceramic fibers may be silicone carbide fibers.
The polymer of the matrix 30 may be epoxy, phenolic, or other suitable polymeric material for the intended end use of the composite article 20. Alternatively, the matrix 30 may be a ceramic material, such a silicon carbide. In another alternative, the matrix 30 may be carbon. Thus, the end composite article 20 may be carbon fiber/carbon matrix, carbon fiber/ceramic matrix, ceramic fiber/carbon matrix, ceramic fiber/ceramic matrix, carbon fiber/polymer matrix or ceramic fiber/polymer matrix, for example. Given this description, one of ordinary skill will recognize other materials that are suited to their particular needs.
A user wraps the fiber layer 28 around the mandrel 42 such that the plurality of needles 44 passes through the interstitial areas 27 of the fiber layer 28 as it is wrapped. As shown in
The fiber layer 28 may be a tape that includes oriented or woven fibers. The tape may be pre-impregnated with a resin that is later used to form the matrix 30 of the composite article 20. Alternatively, the tape or fiber layer 28 may be dry with regard to any resin.
Referring to
The apparatus 40 and method used therewith provide a method for arranging the second fibers 26b with a radial orientation through the fiber layers 28 with little or no disturbance to the first fibers 26a. That is, upon wrapping the fiber layer 28 around the mandrel 42, the needles 44 nestle between the first fibers 26a in the interstitial areas 27 and thereby reduce movement of those fibers to maintain the desired fiber orientation and reduce the possibility of damaging the fibers (i.e., the fibers remain intact).
After threading the second fibers 26b through, the wrapped fiber layers 28 may be further processed to produce the end composite article 20. As an example, if the first fibers 26a are pre-impregnated, the wrapped fiber layers 28 may be thermally treated while remaining on the mandrel 42 to cure the resin. Alternatively, if the first fibers 26a are dry with regard to any resin, the wrapped fiber layers 28 may be impregnated with a resin material. For instance, the resin material may be dip coated onto the wrapped fiber layers 28, sprayed, or resin transfer molded into the first fibers 26a.
After impregnation, the resin may be cured in a known manner before removal of the wrapped fiber layers 28 from the mandrel 42. In an example where the matrix 30 is a ceramic material, the resin may be a pre-ceramic polymer resin that is further thermally treated after curing to convert the pre-ceramic polymer resin to the ceramic material of the matrix 30, such as silicon carbide.
As shown in
In one example, the actuator 60 moves the needles 44 radially outward with regard to the center axis 46 of the mandrel 42 with each revolution of the mandrel 42. Thus, the free end of the needle 44 remains above the wrapped fiber layers 28 but maintains a relatively short extension beyond the radially outer surface of the wrapped fiber layers 28 to thereby reduce spreading. With each revolution, the needles 44 may be incrementally extended from the mandrel 42. Alternatively, the needles 44 may be extended in response to multiple revolutions of the mandrel 42.
Although a combination of features is shown in the illustrated examples, not all of them need to be combined to realize the benefits of various embodiments of this disclosure. In other words, a system designed according to an embodiment of this disclosure will not necessarily include all of the features shown in any one of the Figures or all of the portions schematically shown in the Figures. Moreover, selected features of one example embodiment may be combined with selected features of other example embodiments.
The preceding description is exemplary rather than limiting in nature. Variations and modifications to the disclosed examples may become apparent to those skilled in the art that do not necessarily depart from the essence of this disclosure. The scope of legal protection given to this disclosure can only be determined by studying the following claims.
