Patent Application
20060218873
Architectural columns have long been used for structural support, aesthetic qualities, and artistic purposes. Architecturally correct columns have traditionally assumed a number of different forms. More specifically, traditional architectural columns have been made from wood, steel, concrete, or molded polymers. Recent developments in material processing have led to the use of fiber-reinforced composite materials in the formation of architectural columns. Conventional fiber-reinforced columns are made by a filament-winding process in which a band of fibers or filaments is wound around a rotating mandrel in a helical winding pattern and then cured to produce a structural column. In the helical winding process, the mandrel rotates while a fiber feed carriage traverses back and forth at a speed regulated to generate the desired helical angles. Since fibers provide the greatest compressive strength when oriented in the direction of the load, the helical winding pattern is manipulated to position the fibers as close to parallel with the longitudinal axis of the column as possible.
Unfortunately, using helical winding methods for the production of architectural columns is limited by a number of drawbacks. First, the glass fibers become very slippery when they are impregnated with wet resin. Consequently, the helical winding process mandates that the fibers be wound over the entire length of the mandrel to prevent the fibers from slipping or otherwise moving when winding relatively low angles. Second, by winding the fibers the entire length of the mandrel and around the end of the mandrel, the fiber material may sag between the impregnator and the pay-out eye as the fiber material is traversed back across the longitudinal axis of the mandrel. This sag often varies the orientation of the fibers laid down on the mandrel, thereby leading to lower strength and a rougher surface finish.
Additionally, the formation of architectural columns using helical winding methods produces significant amounts of wasted fiber and resin material. More specifically, the fiber material used in helical winding methods is wound around the ends of the mandrel In order to keep the fiber material on the mandrel secured at a low angle. Consequently, the entire length of the mandrel must be used, even if a shorter column length is desired. As a result, significant amounts of fiber material must then be removed from the formed column to achieve the desired size. Additionally, removal of the resulting helical wound column necessitates that the fiber material domes formed at the ends of the mandrel be cut off, thereby adding additional processing steps, increasing material waste, and increasing processing time and costs to the formation of the architectural column.
In one of many possible embodiments, an architectural column includes a tubular column body having a longitudinal axis extending from a first end to a second end, at least one inner material layer, at least one compression support layer, and at least one outer material layer, wherein the compression support layer includes a composite fabric.
In another embodiment, a method of making an architectural column includes forming an inner layer, forming a support layer, and forming an outer layer, wherein the support layer includes a composite fabric having fibers and a bonding resin, and the column has a longitudinal axis extending from a first end to a second end.
In yet another embodiment, a method of making an architectural column includes forming a column body by filament-winding an inner layer around a mandrel, wrapping a composite fabric around the inner layer, and filament-winding an outer layer around the composite fabric.
The accompanying drawings illustrate various embodiments of the present exemplary system and method and are a part of the specification. The illustrated embodiments are merely examples of the present system and method and do not limit the scope thereof.
a illustrates a side view of a compression resistive column body, according to one exemplary embodiment.
b is a top-view illustrating a cross-section of an architectural column body, according to one exemplary embodiment.
a-6c are simple perspective views illustrating steps in the formation of an architectural column body, according to one exemplary embodiment.
Throughout the drawings, identical reference numbers designate similar, but not necessarily identical, elements.
An exemplary system and method for implementing an architectural column is disclosed herein. More specifically, a system and method are disclosed herein for forming an architectural column that is resistive to compressive loads by incorporating a unidirectional fabric. Numerous specific details are set forth below for purposes of explanation and to provide a thorough understanding of the present system and method.
In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the present system and method for forming an architectural column. It will be apparent, however, to one skilled in the art, that the present method may be practiced without these specific details. Reference in the specification to “one embodiment” or “an embodiment” means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. The appearance of the phrase “in one embodiment” in various places in the specification are not necessarily all referring to the same embodiment.
Referring now to
In one exemplary embodiment, as shown in
According to one exemplary embodiment described herein, each of the above-mentioned layers is generally made from a fiber-reinforced composite material comprising a plurality of fibers reinforced with a bonding resin. Composite materials offer the unique ability to mix and match fibers and bonding resins to develop a material with specific desired properties. Suitable fibers for use in the composite material include, but are in no way limited to, steel, aluminum, ceramics, carbon, graphite, aramids, E-glass and S-glass fibers, other fibers known to those of skill in the art, or combinations thereof.
The bonding resin of the composite material maintains the structural integrity of the composite while providing the load transfer mechanism between the fibers that are incorporated into the structure. In addition to binding the composite structure together, the resin serves to provide corrosion resistance, protects the fibers from external damage, and contributes to the overall composite toughness from surface impacts, cuts, abrasion, and rough handling. Bonding resins come in a variety of chemical families, each designed to provide certain structural performance, cost and/or environmental resistance. Suitable resins include, but are not limited to, thermoset and thermoplastic resins. Examples of suitable thermoset resins include polyester, epoxy, vinyl ester, bisphenol-A fumarate, chlorendic and phenolic resins. Other suitable bonding resins include metal or ceramix matrices.
The bonding resin may also include one or more fillers and/or additives. Fillers are used to improve performance and reduce the cost of the composite material by lowering the cost of the significantly more expensive resin and imparting benefits such as shrinkage control, surface smoothness and crack resistance. Additives expand the usefulness of polymers, enhance their processability, and/or extend product durability.
According to one exemplary embodiment illustrated in
Continuing with
In one exemplary embodiment, the support layer (212) comprises a unidirectional (UD) fabric or a fabric in which a majority of the fibers are aligned in the same direction. The UD fabric (218) may also contain a small amount of fiber or other material aligned in other directions to hold the primary fibers in position, although the other fibers may also offer some structural properties. In one exemplary embodiment, the UD fabric (218) comprises a 0°/90° fabric having approximately 75% of the fibers by weight aligned in one direction. In yet another exemplary embodiment, the UD fabric (218) has approximately 90% of the fibers by weight aligned in one direction. According to these exemplary embodiments, UD fibers are straight and uncrimped. Consequently, using a UD fabric offers the ability to place fibers in the column body (230) where they are most beneficial, in the optimum quantity (no more or less than required), and at the desired angle. More specifically, according to one exemplary embodiment, any range of fibers of the UD fabric (218) may be oriented with regards to a single desired axis including, but not limited to, as low as approximately 10% to 25% of the fibers by weight up to approximately 75% or 90% of the fibers by weight, depending on the fabric used.
According to one exemplary embodiment, the UD fabric (218) forming the support layer (212) comprises a weft UD fabric in which the primary fibers are aligned at substantially 90° relative to the length of the fabric roll. As a result, when used as the composite fabric for the support layer (212), a weft UD fabric yields a support layer (212) with a majority of the fibers oriented at substantially 0° relative to the longitudinal axis (290) of the column body (230). According to one exemplary embodiment, the use of a weft UD fabric yields a support layer (212) with a majority of the fibers oriented between approximately 0° and approximately 20° relative to the longitudinal axis (290) of the column body (230). This configuration provides superior axial load bearing strength, due to fiber orientation, when compared to traditional helically wound columns in which the fibers are typically oriented at about 30° or greater relative to the longitudinal axis of the column.
In another exemplary embodiment, the composite fabric of the support layer (212) comprises a woven fabric. Woven fabrics are produced by the interlacing of warp (0° relative to the fabric roll length) fibers and weft (90°) fibers in a regular pattern or weave style. The fabric's integrity is maintained by the mechanical interlocking of the fibers. Due to the presence of the weft fibers, the woven fabric also provides superior axial load bearing strength when compared to traditional helically wound columns. In another embodiment the composite fabric comprises a multi-axial fabric, or a fabric having one or more layers of long fibers held in place by a secondary non-structural stitching thread. The main fibers can be any of the above-mentioned structural fibers available in any combination. The stitching process incorporated by the multi-axial fabric allows a variety of fiber orientations, beyond the simple 0/90° of woven fabrics, to be combined into one fabric.
In another embodiment the composite fabric of the support layer (212) comprises a hybrid fabric, a fabric having more than one type of structural fiber in its construction. The incorporation of a hybrid fabric allows two fibers to be presented in just one layer of fabric rather than two. In one embodiment a woven hybrid has one fiber running in the weft direction and the second fiber running in the warp direction. In another embodiment the hybrid fabric includes alternating threads of each fiber in each warp/weft direction. Although hybrids are most commonly found in 0/90° woven fabrics, they may also be used in 0/90° stitched, unidirectional, and/or multi-axial fabrics.
Generally, the fiber-reinforced column body is not limited to the embodiments described above, but may include any number of inner and outer layers and support layers. Additional layers may use different composite materials, fabrics, winding patterns, fiber orientations, fibers, bonding agents, or combinations thereof. For example,
Referring again to the exemplary embodiment of
In one embodiment, the taper of the column (100) may be achieved by forming the column body (130) with the desired taper and applying a surface material (132) of uniform thickness over the column body (130). A method of forming the column body (130) is described in more detail below. In another embodiment, the taper may be achieved by forming a column body (130) of uniform diameter from top to bottom and coating the column body (130) with a surface material having a thickness that decreases from the bottom toward the top of the column body (130). The taper may also be achieved by a combination of the above methods, or by any other method known to those of skill in the art.
The column (100) may also include a base (140) and/or plinth (150). The decorative base (140) the column (100) helps to define the order or style of the column (100). The base (140), along with the capital (110) and the column body (130), gives the column (100) its own distinctive character. The base (140) is typically round with various designs and moldings. The base (140) rests on the plinth (150), generally a square or rectangular block or slab with short legs (152). The plinth (150) provides an interface between the base (140) and the ground or floor, and can be designed to raise the column body (130) off the ground to allow air to circulate in the interior of the column (100). The base (140) and plinth (150) can be molded in one piece or may constitute separate pieces, but generally are formed independent of the column body (130).
Referring now to
As illustrated in
As illustrated in
As shown in
In one exemplary embodiment, the fabric (618) may be pre-impregnated with a bonding resin such that the fabric (618) may omit passing through a resin bath prior to wrapping over the inner layer (610). In another embodiment, the fabric (618) is wet-wrapped around the inner layer (610) by either passing the fabric (618) through a resin bath (not shown) before wrapping it around the inner layer (610), or by wrapping the fabric (618) around the inner layer (610) and then coating it with a bonding resin. The fabric (618) may be coated with the bonding resin by any means, such as with a brush, squeegee, rag, cloth, roller, or any other means known to those of skill in the art.
After the support layer(s) (612) has been formed around the inner layer(s) (step 520;
Once the layers are deposited, the composite column is cured (step 540;
With the column body (630) cured (step 540;
In conclusion, the structure of the composite column body described above permits the quick and efficient manufacture of lightweight architectural columns having substantial load-bearing capacities. The column and methods of making it reduce fiber and resin waste, cut processing times, and reduce overall costs compared to traditional helical wound structures.
The preceding description has been presented only to illustrate and describe exemplary embodiments of the present system and method. It is not intended to be exhaustive or to limit the system and method to any precise form disclosed. Many modifications and variations are possible in light of the above teaching. It is intended that the scope of the system and method be defined by the following claims.
