WO2025006501A1 - Techniques permettant de fabriquer des barres et des barres composites - Google Patents

Techniques permettant de fabriquer des barres et des barres composites Download PDF

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Publication number
WO2025006501A1
WO2025006501A1 PCT/US2024/035472 US2024035472W WO2025006501A1 WO 2025006501 A1 WO2025006501 A1 WO 2025006501A1 US 2024035472 W US2024035472 W US 2024035472W WO 2025006501 A1 WO2025006501 A1 WO 2025006501A1
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WIPO (PCT)
Prior art keywords
mold cavity
fiber
polymer
fluid
fiber strands
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PCT/US2024/035472
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English (en)
Inventor
Massimiliano Moruzzi
Francesco Iorio
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Xaba Inc
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Xaba Inc
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Priority claimed from US18/752,642 external-priority patent/US20240424753A1/en
Application filed by Xaba Inc filed Critical Xaba Inc
Publication of WO2025006501A1 publication Critical patent/WO2025006501A1/fr
Anticipated expiration legal-status Critical
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29B—PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
    • B29B15/00—Pretreatment of the material to be shaped, not covered by groups B29B7/00 - B29B13/00
    • B29B15/08—Pretreatment of the material to be shaped, not covered by groups B29B7/00 - B29B13/00 of reinforcements or fillers
    • B29B15/10—Coating or impregnating independently of the moulding or shaping step
    • B29B15/12—Coating or impregnating independently of the moulding or shaping step of reinforcements of indefinite length
    • B29B15/122—Coating or impregnating independently of the moulding or shaping step of reinforcements of indefinite length with a matrix in liquid form, e.g. as melt, solution or latex
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C70/00—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts
    • B29C70/04—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts comprising reinforcements only, e.g. self-reinforcing plastics
    • B29C70/28—Shaping operations therefor
    • B29C70/40—Shaping or impregnating by compression not applied
    • B29C70/50—Shaping or impregnating by compression not applied for producing articles of indefinite length, e.g. prepregs, sheet moulding compounds [SMC] or cross moulding compounds [XMC]
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C70/00—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts
    • B29C70/04—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts comprising reinforcements only, e.g. self-reinforcing plastics
    • B29C70/28—Shaping operations therefor
    • B29C70/54—Component parts, details or accessories; Auxiliary operations, e.g. feeding or storage of prepregs or SMC after impregnation or during ageing
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C70/00—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts
    • B29C70/04—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts comprising reinforcements only, e.g. self-reinforcing plastics
    • B29C70/28—Shaping operations therefor
    • B29C70/54—Component parts, details or accessories; Auxiliary operations, e.g. feeding or storage of prepregs or SMC after impregnation or during ageing
    • B29C70/541—Positioning reinforcements in a mould, e.g. using clamping means for the reinforcement
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C70/00—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts
    • B29C70/04—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts comprising reinforcements only, e.g. self-reinforcing plastics
    • B29C70/28—Shaping operations therefor
    • B29C70/54—Component parts, details or accessories; Auxiliary operations, e.g. feeding or storage of prepregs or SMC after impregnation or during ageing
    • B29C70/543—Fixing the position or configuration of fibrous reinforcements before or during moulding
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C70/00—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts
    • B29C70/04—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts comprising reinforcements only, e.g. self-reinforcing plastics
    • B29C70/28—Shaping operations therefor
    • B29C70/54—Component parts, details or accessories; Auxiliary operations, e.g. feeding or storage of prepregs or SMC after impregnation or during ageing
    • B29C70/545—Perforating, cutting or machining during or after moulding
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C70/00—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts
    • B29C70/04—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts comprising reinforcements only, e.g. self-reinforcing plastics
    • B29C70/28—Shaping operations therefor
    • B29C70/54—Component parts, details or accessories; Auxiliary operations, e.g. feeding or storage of prepregs or SMC after impregnation or during ageing
    • B29C70/56—Tensioning reinforcements before or during shaping
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C2793/00—Shaping techniques involving a cutting or machining operation
    • B29C2793/0027—Cutting off
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C53/00—Shaping by bending, folding, twisting, straightening or flattening; Apparatus therefor
    • B29C53/02—Bending or folding
    • B29C53/08—Bending or folding of tubes or other profiled members
    • B29C53/083—Bending or folding of tubes or other profiled members bending longitudinally, i.e. modifying the curvature of the tube axis
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29L—INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES
    • B29L2031/00—Other particular articles
    • B29L2031/001—Profiled members, e.g. beams, sections

Definitions

  • the various embodiments relate generally to mechanics of materials and related fabrication techniques and, more specifically, to fabricating composite rebars and beams.
  • GFRP glass fiber reinforced polymer
  • GFRP rebar which is not subject to corrosion, is a viable alternative to steel rebar given that GFRP rebar eliminates one of the biggest vulnerabilities of reinforced concrete - corrosion-induced concrete spalling.
  • GFRP rebar is typically formed by pultrusion of a bundle of resin-impregnated glass fibers through a die that cures and shapes the rebar as the resin polymerizes. Such an approach results in the reinforcing fiber accounting for the majority of the mass of the rebar, which greatly increases the cost of the rebar.
  • Another drawback of using GFRP rebar is that the fiber bundle and the polymerized resin may not simultaneously contribute to the mechanical performance of the rebar.
  • the fibers of a given bundle typically are not straight and parallel with the axis of the rebar. Instead, the fibers of a given bundle usually follow curved paths that are only roughly parallel to the axis of the rebar. Such fibers deflect and straighten out under a tensile load and, therefore, primarily contribute to the axial rigidity of the rebar only after a reasonable amount axial deflection of the rebar has occurred. Consequently, the large number of reinforcing fibers in a conventional GFRP rebar confer only some axial rigidity to the rebar, which means that the axial strength of the reinforcing fibers in GFRB rebar is typically used inefficiently.
  • a method for fabricating a composite structural member includes: positioning each fiber strand included in one or more fiber strands at a respective location within a mold cavity of a polymer mold; exerting a tensile force on each fiber strand included in the one or more fiber strands; filling the mold cavity with a fluid that includes a polymer; and curing the fluid within the mold cavity while the tensile force continues to be exerted on each fiber strand included in the one or more fiber strands.
  • At least one technical advantage of the disclosed techniques relative to the prior art is that the disclosed techniques enable fiber-reinforced composite rebars and beams that have mechanical properties equivalent to conventional composite rebars and beams that include many more reinforcing fibers to be fabricated.
  • a further advantage is that the disclosed techniques enable fiber-reinforced composite rebars and beams that include pre-tensioned reinforcing fibers that enhance the mechanical properties of those rebar and beams to be fabricated.
  • Figure 1 conceptually illustrates a cross section of a composite structural member, according to various embodiments.
  • Figure 2 conceptually illustrates a side cross section of the composite structural member of Figure 1 , according to various embodiments
  • Figure 3 conceptually illustrates a fabrication system configured to implement one or more aspects of the various embodiments.
  • Figure 4 is a more detailed illustration of the polymer mold of Figure 3, according to various embodiments.
  • Figure 5A is a plan view of the fiber-positioning plate of Figure 4, according to various embodiments.
  • Figure 5B is a side view of the fiber-positioning plate of Figure 4, according to various embodiments.
  • Figure 6 is a more detailed illustration of the polymer mold of Figure 3, according to various other embodiments.
  • Figure 7 sets forth a flowchart of method steps for fabricating a composite structural member using an extrusion process, according to various embodiments.
  • Figures 8A - 8D conceptually illustrate various steps included in the method of Figure 7, according to various embodiments.
  • Figure 9 sets forth a flowchart of method steps for fabricating a composite structural member using an extrusion process, according to other various embodiments.
  • FIGS. 10A - 10D conceptually illustrate various steps included in the method of Figure 9, according to other various embodiments
  • FIG. 1 conceptually illustrates a cross section of a composite structural member 100, according to various embodiments.
  • composite structural member 100 is a fiber-reinforced polymeric member, such as a reinforcing bar (commonly referred to as “rebar”) that can be employed to structurally reinforce a concrete structure.
  • rebar reinforcing bar
  • composite structural member 100 has a circular cross-section.
  • composite structural member 100 can have any technically feasible cross section that can be achieved via the methods and techniques describe herein, such as an oval, rectangular, or square cross-section.
  • composite structural member 100 can have a more complex cross section, such as a ring, hollow rectangle, T-beam, I-beam, L-beam, or U-channel, or any other cross-section that can provide bending and/or axial rigidity to a concrete structure when incorporated therein.
  • composite structural member 100 includes one or more fiber strands 101 that are positioned within a cured polymer 102 (cross-hatched) of composite structural member 100.
  • Fiber strands 101 can include one or more glass fibers, carbon fibers, recycled fibers (such as polymer-based fibers), aramid fibers, natural fibers, and/or the like. Further, in some embodiments, each fiber strand 101 is a single fiber, and in other embodiments, each fiber strand 101 is a group of braided or twisted fibers. In some embodiments, the type of fiber material included in fiber strands 101 is selected based on one or more materials included in cured polymer 102.
  • Cured polymer 102 can be any polymer suitable for use in a reinforcement bar or other structural member.
  • cured polymer includes at least one of a thermoplastic polymer, a thermo-setting resin, or a polyamide-containing material.
  • the polymer or polymers included in cured polymer 102 can be selected based on specific requirements of the application for composite structural member 100, including mechanical performance and durability in various environmental conditions.
  • the diameter, material, and position of fiber strands 101 can be selected based on a particular application for fiber-reinforced plastic member 100.
  • fiber strands 101 are selected to provide additional axial rigidity and increased tensile strength to composite structural member 100.
  • one or more fiber strands 101 are positioned within cured polymer 102 (cross-hatched) of composite structural member 100, and are reinforcing fibers that provide additional axial rigidity and increased tensile strength to composite structural member 100.
  • composite structural member 100 includes four fiber strands 101 that are positioned between an outer surface 121 of composite structural member 100 and a center axis 122 of composite structural member 100.
  • any other technically feasible number of fiber strands 101 can be positioned within cured polymer 102.
  • composite structural member 100 includes more than or fewer than four fiber strands 101 positioned between outer surface 121 and center axis 122 of composite structural member 100.
  • each fiber strand 101 is separated from each other fiber strand 101.
  • each fiber strand 101 does not contact another fiber strand 101 included in composite structural member 100.
  • fiber strands 101 are positioned to enable bending of composite structural member 100 into a specified shape during fabrication.
  • fiber strands 101 may have a composition and be positioned within cured polymer 102 to provide flexibility to composite structural member 100 during the bending process.
  • fiber strands 101 may include an elastic fiber, such as hemp, that enables bending of a segment of composite structural member 100 during fabrication.
  • fiber strands 101 may be interwoven, layered, or otherwise positioned within cured polymer 102 to allow for movement and bending of composite structural member 100 during a bending process without compromising the structural integrity of composite structural member 100.
  • fiber strands 101 may include a surface treatment that enables each fiber in fiber strands 101 to elongate, such as the formation of micro-disruptions or micro-cuts on the surface of each fiber.
  • a surface treatment that enables each fiber in fiber strands 101 to elongate, such as the formation of micro-disruptions or micro-cuts on the surface of each fiber.
  • the ability of the fibers within fiber strands 101 to elongate enables the bending of composite structural member 100 during a bending process described below.
  • fiber strands 101 are pre-tensioned when composite structural member 100 is formed, for example via the exertion of a tensile force on fiber strands 101 during fabrication of composite structural member 100.
  • fiber strands 101 are generally straight and parallel with the longitudinal axis of composite structural member 100, which enhances the mechanical performance of composite structural member 100.
  • fiber strands 101 can contribute to the axial rigidity of composite structural member 100 before axial deflection of the rebar has occurred, since fiber strands 101 do not follow curved paths within composite structural member 100.
  • fiber strands 101 have a plurality of knots formed therein. In such embodiments, the knots act a uniform distribution of anchoring points between fiber strands 101 and cured polymer 102, thereby producing homogeneous structure behavior in composite structural member 100.
  • the knots act a uniform distribution of anchoring points between fiber strands 101 and cured polymer 102, thereby producing homogeneous structure behavior in composite structural member 100.
  • FIG. 2 conceptually illustrates a side cross section of composite structural member 100, according to various embodiments.
  • composite structural member 100 includes multiple pre-tensioned fiber strands 101 that are enclosed within cured polymer 102.
  • Pre-tensioned fiber strands 101 are formed with a tensile force (not shown) exerted thereon during fabrication of composite structural member 100. Therefore, pre-tensioned fiber strands 101 are straight and parallel with a longitudinal axis 205 of composite structural member 100.
  • Pre-tensioned fiber strands 101 also include a plurality of knots 202 formed therein.
  • pretensioned fiber strands 101 are parallel with longitudinal axis 205 and do not follow curved paths within composite structural member 100, an axial load 206 parallel with longitudinal axis 205 that is applied to composite structural member 100 encounters the weakest mechanical interaction between pre-tensioned fiber strands 101 and cured polymer 102. Consequently, fiber strands may not respond to axial load 206 simultaneously with cured polymer 102.
  • knots 202 act as additional anchoring points between pre-tensioned fiber strands 101 and cured polymer 102, thereby increasing the mechanical interaction or bond between pre-tensioned fiber strands 101 and cured polymer 102.
  • knots 202 are equally spaced along fiber strands 101 as shown. In other embodiments, knots 202 are not equally space and are instead disposed at certain locations along fiber strands 101 to provide enhanced mechanical coupling at specified locations within composite structural member 100.
  • FIG. 3 conceptually illustrates a fabrication system 300 configured to implement one or more aspects of the various embodiments.
  • Fabrication system 300 enables fabrication of fiber-reinforced composite rebars and beams that have the mechanical properties of conventional composite rebars and beams having orders of magnitude more reinforcing fibers.
  • the fiber-reinforced composite rebars and beams include pre-tensioned and precisely positioned reinforcing fibers disposed within a cured polymer that enhance the mechanical properties of the rebars and beams.
  • fabrication system 300 includes a fiber spool magazine 310, a fiber impregnator 120, a polymer mold 130, a polymer supply system 140, a tensioning device 150, a cutting device 160, and a bending station 170.
  • Fiber spool magazine 310 includes a plurality of fiber spools 311 that each supply a respective fiber strand 301 for inclusion in the composite structural members 309 that are produced by fabrication system 300.
  • fiber strands 301 are consistent with fiber strands 101 of Figure 1 and Figure 2.
  • fiber strands 301 are conveyed or routed to fiber impregnator 320 via rollers 311 , guides, and/or the like.
  • Fiber impregnator 320 saturates, wets, or otherwise impregnates fiber strands 301 prior to the molding and curing of polymer-containing fluid 303 with a suitable resin or other impregnation liquid.
  • Fiber impregnation is performed by fiber impregnator 320 to enhance or enable bonding between fiber strands 301 and a polymer-containing fluid 303 employed to form the cured polymer bulk material of composite structural members 309.
  • fiber impregnation involves pulling fiber strands 301 through a bath of a suitable resin or impregnation liquid or by spraying a suitable resin or impregnation liquid onto fiber strands 301 .
  • fiber strands 301 are conveyed or routed to fiber impregnator 320 via rollers 311 , guides, and/or the like.
  • the material or materials employed to impregnate fiber strands 301 can be selected depending on the type of fiber included in fiber strands 301 and/or the type of polymer in polymer-containing fluid 303.
  • Examples of such impregnation liquids or resins include polyester, polyurethane, vinyl ester, and epoxy resins.
  • Different fibers such as glass, carbon, or aramid fibers
  • the type of fiber in fiber strands 301 can determine the resin or impregnation liquid used to impregnate fiber strands 301 .
  • fibers typically require resins that can penetrate and adhere well to the surface of such fibers, such as epoxy, polyester or vinyl ester.
  • fiber strands 301 include carbon fibers, which are more chemically inert than glass fibers, to achieve optimal bonding
  • fiber strands 301 can be impregnated with specialized epoxy resins.
  • the impregnation liquid is selected to be compatible with that specific polymer to ensure a cohesive structure of composite structural members 309.
  • a wetting agent can be included in the resin or impregnation liquid used to impregnate fiber strands 301 .
  • the impregnation liquid is selected to chemically and/or mechanically bond well with that thermoplastic polymer.
  • the type of fiber in fiber strands 301 can determine the resin or impregnation liquid used to impregnate fiber strands 301 .
  • Polymer mold 330 is a chamber of fabrication system 300, such as a forming die, configured to form the bulk portion of composite structural members 309 by curing polymer-containing fluid 303 disposed within polymer mold 330.
  • polymer mold 330 cures the polymer-containing fluid 303 disposed within polymer mold 330 while a tensile force (not shown) is exerted on each fiber strand 301 disposed within polymer mold 330, for example via tensioning device 150.
  • polymer mold 330 cures the polymer-containing fluid 303 disposed within polymer mold 330 while each fiber strand 301 disposed within polymer mold 330 is positioned at a respective location.
  • a tensile force (not shown) is exerted on each fiber strand 301 disposed within polymer mold 330, for example via tensioning device 150.
  • polymer mold 330 cures the polymer-containing fluid 303 disposed within polymer mold 330 while each fiber strand 301 disposed within polymer mold 330 is positioned at a
  • FIG. 4 is a more detailed illustration of polymer mold 330, according to various embodiments.
  • polymer mold 330 includes a mold cavity 430, one or more inlets 401 for entry of polymer-containing fluid, a mold outlet 402 located at a first end 431 of mold cavity 430, and a fiberpositioning plate 420 disposed on a second end 432 of mold cavity 430.
  • Also shown in Figure 4 are multiple fiber strands 301 positioned at different respective locations within mold cavity 430.
  • Polymer mold 330 receives a polymer-containing fluid, such as polymer-containing fluid 303 in Figure 3 via inlets 401 and cures the polymer- containing fluid to form a segment of a composite structural member 309 shown in Figure 3.
  • inlets 401 are located proximate first end 431 of mold cavity 430, which is the opposite end of mold cavity 430 from second end 432. In other embodiments, one or more inlets 401 are located at different locations along the length of mold cavity 430 and/or at first end 431 of mold cavity 430, for example between fiber-locating openings 421 of fiber-positioning plate 420.
  • Fiber-positioning plate 420 includes one fiber-locating opening for each of the one or more fiber strands 301 positioned within mold cavity 430. In operation, one fiber strand 301 is routed through each fiber-locating opening 421 during fabrication of the composite structural members 309 in Figure 3.
  • each fiber-locating opening 421 of fiberpositioning plate 420 positions one fiber strand 301 at a different respective location within mold cavity 430.
  • each different respective location is located between an inner surface 432 of mold cavity 430 and a center axis 405 of mold cavity 430.
  • fiber-positioning plate 420 is described below in conjunction with Figures 5A and 5B.
  • Figure 5A is a plan view of fiber-positioning plate 420 and Figure 5B is a side view of fiber-positioning plate 420, according to various embodiments.
  • fiber-positioning plate 420 includes four fiber-locating openings 421 for positioning fiber strands 301 (cross-hatched) within a mold cavity, such as mold cavity 430 in Figure 4.
  • fiberpositioning plate 420 can include any suitable number of appropriately positioned fiber-locating openings 421.
  • polymer mold 330 is implemented as a cooling mold that forms composite structural members 309 via an extrusion process.
  • the polymer-containing fluid received by mold cavity 430 includes a thermoplastic and/or polyamide, both of which are cured by cooling.
  • the polymer-containing fluid received by mold cavity 430 cools within a cooling region 435 of polymer mold 330.
  • the polymer-containing fluid received by mold cavity 430 is cooled to a temperature below a solidification temperature of the polymer-containing fluid.
  • mold cavity 430 receives the polymer-containing fluid received in a casting region 434 and cools the polymer- containing fluid in a cooling region 435. After sufficient cooling, a solidified segment of a composite structure member 309 exits polymer mold 330 via mold outlet 402. Typically, in the extrusion process, the solidified segment of a composite structure member 309 continuously exits mold outlet 402, for example at a fixed velocity.
  • polymer mold 330 is implemented as a thermal curing mold that forms composite structural members 309 via an injection process.
  • the polymer-containing fluid received by mold cavity 430 includes a thermo-setting polymer that is cured by heating.
  • the polymer-containing fluid received by mold cavity 430 is heated within a thermal curing region of polymer mold 330.
  • One such embodiment is described below in conjunction with Figure 6.
  • FIG. 6 is a more detailed illustration of polymer mold 630, according to various embodiments.
  • polymer mold 630 can be consistent with polymer mold 330 of Figures 3 and 4, except that polymer mold 630 includes a thermal curing region 635 and associated thermal curing devices 650 in lieu of a cooling region 435.
  • thermal curing devices 650 are heat-generating devices for thermally curing the polymer-containing fluid disposed within thermal curing region 635.
  • Thermal curing devices 650 can include any devices capable of thermally curing the polymer-containing fluid disposed within thermal curing region 635, such as an electrical heat source, a microwave heat source, a source of ultra-violet rays, and/or a source of infra-red rays.
  • polymer mold 630 receives a polymer-containing fluid via inlet 601 and thermally cures the polymer-containing fluid to form a segment of a composite structural member 309 shown in Figure 3.
  • the polymer-containing fluid received by mold cavity 430 is heated to a temperature equal to or greater than a curing temperature of the polymer-containing fluid.
  • mold cavity 430 receives the polymer-containing fluid received in a casting region 634 and cures the polymer-containing fluid in thermal curing region 635.
  • a solidified segment of a composite structure member 309 exits polymer mold 330 via mold outlet 402.
  • a discrete segment of a composite structure member 309 is advanced from polymer mold 630.
  • polymer supply system 340 provides polymer- containing liquid 303 to an inlet of polymer mold 330.
  • Polymer-containing fluid 303 can be a liquid.
  • polymer-containing fluid 303 can be a waxy or semi-solid fluid or other non-solid fluid.
  • polymer supply system 340 can vary in configuration depending on the type of polymer included in polymer-containing fluid 303 as well as the specific requirements of fabrication process for composite structure member 309.
  • polymer supply system 340 is implemented as a hopper/auger system that includes a hopper to hold polymer pellets that are then fed into a melting device or chamber via an auger.
  • polymer supply system 340 is implemented as a liquid distribution system for thermo-setting resins or liquid polymers.
  • the liquid distribution system can include pump systems for pumping liquid polymers or resins to the polymer mold, metering systems for precision control of the flow rate of polymer-containing fluid 303, and mixing systems.
  • a mixing system can combine the two components in the correct ratio before delivering the mixture to polymer mold 330.
  • polymer supply system 340 includes a mixing system that combines a first part of a thermosetting resin included in the polymer-containing liquid with a second part of the thermo-setting resin included in the polymer-containing liquid before the polymer- containing liquid enters polymer mold 330.
  • polymer supply system 340 is implemented as a granule feeding system that uses granules of polymers instead of pellets.
  • the granule feeding system can have feeding mechanisms to a pellet-handling system, such as a hopper and/or vibratory feeders to ensure continuous supply.
  • Tensioning device 350 facilitates properly alignment and tension of fiber strands 301 during the process of fabricating composite structural members 309.
  • tensioning device 350 includes pulling rollers that grip a segment of composite structural member 309 that has exited polymer mold 330, thereby maintaining tension on the segments of fiber strands 301 disposed within polymer cavity 330.
  • tensioning device 350 includes tensioning clamps, such as mechanical or pneumatic clamps can hold and tension in fiber strands 301 . In such embodiments, these clamps can adjust tension dynamically to ensure consistent alignment of fiber strands 301 with polymer cavity 330.
  • tensioning device 350 includes a servo-driven system that can provide precise control of fiber tension.
  • tensioning device 350 includes weight-based tensioning that can apply constant tension to fiber strands 301.
  • tensioning device 350 includes hydraulic tensioning system, which can provide adjustable and consistent tensioning of fiber strands 301.
  • Cutting device 360 cuts a continuous composite structural member 304 that is produced by polymer mold 330 into composite structural members 309.
  • cutting device 360 is selected to be capable of cleanly cutting the rebar to the desired length without damaging the fibers or the polymer matrix.
  • cutting device 360 can be selected based on various factors, such as the type of polymer included in composite structural members 309, the type of fibers included in composite structural members 309, the required precision of the cut, and the production speed.
  • cutting device 360 includes mechanical shear cutters, which can be used for most thermoplastic structural members. These cutters apply a shearing force to cut through the material.
  • cutting device 360 includes saw blades, such as circular saw blades or band saws, which can be used for cutting thicker or more rigid structural members.
  • the blade material and tooth design for such saw blades generally depends on the type of polymer and fibers included in composite structural member 304.
  • cutting device 360 includes laser cutters for precise cutting, especially for intricate shapes and/or high-strength fibers.
  • cutting device 360 includes hot knife cutters for thermoplastic polymers. Hot knife cutters can melt through such material, providing a clean cut without fraying the fiber strands 301 disposed within composite structural member 304.
  • cutting device 360 includes waterjet cutters, which employ high-pressure waterjets to cut through various types of structural members without generating heat, thereby preventing thermal degradation.
  • cutting device 360 includes rotary cutting devices with replaceable blades, which can provide clean and consistent cuts. Rotary cutting devices can facilitate the fabrication of composite structural members 309 in continuous production lines.
  • Bending station 370 heats, bends, and cools composite structural members 3091.
  • composite structural members 309 include polyamide
  • composite structural members 309 can be bent to a non-linear shape, such as an L configuration, a U configuration, and the like.
  • Polyamide is a polymer that has high flexibility and tensile strength, and therefore is well-suited for applications requiring bendability.
  • bending station 370 is configured to heat a particular portion of a composite structural member 309 to a temperature at or above a softening point of polyamide, facilitate or cause the bending of the composite structural member 309 at the heated portion, and cool the resulting non-linear composite structural member 308 until no longer bendable.
  • bending station 370 can include jigs or other manual tools and/or an automated bending system.
  • a novel extrusion process is employed to fabricate a composite rebar, beam, or other structural member.
  • a fiber-reinforced composite member with a constant cross-section can be continuously formed by the pulling of a plurality of resin-impregnated reinforcing fibers (or braided strands) through a heated die.
  • the cross-section of the fiber- reinforced composite member is determined by the die opening.
  • the reinforcing fibers which are typically compressed together via the die opening, are bundled together within the fiber-reinforced composite member and are not discretely positioned within the composite member.
  • Figure 7 sets forth a flowchart of method steps for fabricating a composite structural member using an extrusion process, according to various embodiments.
  • Figures 8A - 8D conceptually illustrate various steps included in the method of Figure 7, according to various embodiments. Although the method steps are described in conjunction with the systems of Figures 1 - 6, persons skilled in the art will understand that any system configured to perform the method steps, in any order, is within the scope of the embodiments.
  • a method 700 begins at step 701 , where fabrication system 300 routes fiber strands 301 from fiber spool magazine 310 to fiber impregnator 320 and impregnates fiber strands 301 with fiber impregnator 320.
  • fiber strands 301 are not wetted or impregnated with a liquid. In such embodiments, step 701 is not performed.
  • each fiber strand 301 is positioned at a respective location within mold cavity 430, as shown in Figure 8A.
  • Figure 8A is a cross-sectional side view of a mold cavity 430 during a fiber-positioning step, according to various embodiments.
  • fiber strands 301 are routed into mold cavity 430 through fiber-positioning plate 420.
  • fiber strands 301 are positioned at targeted and separate locations within mold cavity 430.
  • fiber strands 301 extend into a previously cured segment of continuous composite structural member 304 (not shown).
  • fabrication system exerts a tensile force 801 on each of fiber strands 301 disposed within mold cavity 430, as shown in Figure 8B.
  • Figure 8B is a cross-sectional side view of polymer mold 330 during a fiber-tensioning step, according to various embodiments.
  • a tensile force 801 is exerted against fiber strands 301 so that fiber strands 301 are under tension while disposed within mold cavity 430.
  • tensile force 801 is exerted on fiber strands 301 via a previously cured segment of continuous composite structural member 304 (not shown) that includes fiber strands 301 .
  • tensile force can be generated by tensioning device 350.
  • tensile force 801 is exerted on fiber strands via a second fiber-positioning plate 802.
  • step 704 mold cavity 430 is filled with polymer-containing fluid 303, as shown in Figure 8C.
  • Figure 8C is a cross-sectional side view of polymer mold 330 during a polymer filling step, according to various embodiments.
  • polymer-containing fluid 303 which can be a molten or softened thermoplastic or polyamide, is injected or flows into casting region 434 of mold cavity 430 via one or more inlets 401 .
  • polymer-containing fluid 303 is a liquid, while in other embodiments, polymer-containing fluid 303 is a polymer that has been heated to a temperature equal to or greater than a softening temperature of the polymer.
  • polymer-containing fluid 303 fills mold cavity 430, envelops fiber strands 301 , and flows or is forced toward mold outlet 402. During step 704, tensile force 801 continues to be exerted on fiber strands 301 .
  • step 705 polymer-containing fluid 303 disposed within mold cavity 430 is cured via cooling, as shown in Figure 8D.
  • Figure 8D is a cross-sectional side view of polymer mold 330 during a curing step, according to various embodiments.
  • the thermoplastic or polyamide included in polymer-containing fluid 303 cools and solidifies to form a portion of continuous composite structural member 304 with strong surface adhesion between fiber strands 301 and the solidified polymer.
  • the thermoplastic or polyamide cools while passing through or being extruded through cooling region 435 of mold cavity 430, for example via tensile force 801.
  • continuous composite structural member 304 is formed in a continuous process while being extruded from mold cavity 430.
  • composite structural members 309 are produced by cutting continuous composite structural member 304 into segments via cutting device 360.
  • composite structural members 309 are bent to form non-linear composite structural members 308 at bending station 370.
  • composite structural members 309 can include polyamide, which can be reheated and softened after curing.
  • a novel injection process is employed to fabricate a composite rebar, beam, or other structural member.
  • individual fibers or braided strands
  • a polymer-containing fluid is then injected into the mold and cured via thermal curing to form a segment of a fiber-reinforced composite member.
  • a tensile force continues to be exerted on the reinforcing fibers within the mold cavity and a discrete segment of a composite structural member is formed in the mold cavity.
  • Figure 9 sets forth a flowchart of method steps for fabricating a composite structural member using an extrusion process, according to other various embodiments.
  • Figures 10A - 10D conceptually illustrate various steps included in method of Figure 9, the fabrication process, according to various embodiments. Although the method steps are described in conjunction with the systems of Figures 1 - 6, persons skilled in the art will understand that any system configured to perform the method steps, in any order, is within the scope of the embodiments.
  • a method 900 begins at step 901 , where fabrication system 300 impregnates fiber strands 301 with fiber impregnator 320.
  • step 901 can be consistent with step 701 of Figure 7.
  • each fiber strand 301 is positioned at a respective location within mold cavity 430, as shown in Figure 10A.
  • Figure 10A is a cross-sectional side view of a polymer mold 330 during a fiber-positioning step, according to other various embodiments.
  • fiber strands 301 are routed into mold cavity 430 through fiber-positioning plate 420.
  • fiber strands 301 are positioned at targeted and separate locations within mold cavity 430.
  • fiber strands 301 extend into a previously cured segment of continuous composite structural member 304.
  • step 903 fabrication system exerts a tensile force 801 on each of fiber strands 301 disposed within mold cavity 430, as shown in Figure 10B.
  • Figure 10B is a cross-sectional side view of mold cavity 430 during a fiber-tensioning step, according to various embodiments.
  • step 903 can be consistent with step 703 of Figure 7.
  • step 904 mold cavity 430 is filled with polymer-containing fluid 303, as shown in Figure 10C.
  • Figure 10C is a cross-sectional side view of polymer mold 330 during a polymer filling step, according to various embodiments.
  • polymer-containing fluid 303 which can be a molten or softened thermos-setting plastic, is injected or flows into casting region 434 of mold cavity 430 via one or more inlets 401 .
  • polymer-containing fluid 303 is a liquid, while in other embodiments, polymer-containing fluid 303 is a polymer that has been heated to a temperature equal to or greater than a softening temperature of the polymer.
  • polymer-containing fluid 303 fills mold cavity 430, envelopes fiber strands 301 , and flows or is forced toward mold outlet 402. During step 904, tensile force 801 continues to be exerted on fiber strands 301 .
  • step 905 polymer-containing fluid 303 disposed within mold cavity 430 is cured via heating, as shown in Figure 10D.
  • Figure 10D is a cross-sectional side view of polymer mold 330 during a curing step, according to various embodiments.
  • the thermos-setting plastic included in polymer-containing fluid 303 is thermally cured and solidifies to form a portion of continuous composite structural member 304 with strong surface adhesion between fiber strands 301 and the solidified polymer.
  • the thermo-setting plastic cures in thermal curing region 635.
  • thermal curing region 635 includes most or all of mold cavity 430.
  • thermal curing region 635 corresponds to a portion of mold cavity proximate mold outlet 402.
  • step 906 composite structural members 309 are produced by cutting continuous composite structural member 304 into segments via cutting device 360.
  • a pre-curing process is performed on polymer- containing fluid 303 disposed within mold cavity 430.
  • the precuring activates the polymerization process within an inner portion of the continuous composite structural member 304 being fabricated.
  • the partial curing apparatus enables surface shaping of the composite structural member 304 being fabricated prior to a final curing process. Such embodiments are described below in conjunction with steps 911 - 913.
  • step 911 polymer-containing fluid 303 within thermal curing region 635 of mold cavity 430 is pre-cured while a tensile force is exerted on fiber strands 301 .
  • thermal curing devices 650 initiates the polymerization of polymer-containing fluid 303 via microwaves directed to a center region of mold cavity 330, ultra-violet rays directed to the center region of mold cavity 330, and/or infra-red rays directed to the center region of mold cavity 330.
  • step 912 surface shaping is performed on pre-cured continuous composite structural member 304. Because the outer region of pre-cured continuous composite structural member 304 is not fully cured, the outer region of pre-cured continuous composite structural member 304, such as the surface, can be modified.
  • a suitable texture can be applied to the surface of pre-cured continuous composite structural member 304.
  • step 913 a final curing process is performed on pre-cured continuous composite structural member 304.
  • a final thermal curing process may be performed on the shaped continuous composite structural member 304.
  • Method 900 then proceeds to step 906, in which composite structural members 309 are produced by cutting continuous composite structural member 304 into segments via cutting device 360.
  • the various embodiments described herein provide techniques that enable fabrication of fiber-reinforced composite rebars and beams that have the mechanical properties of conventional composite rebars and beams having orders of magnitude more reinforcing fibers.
  • the fiber-reinforced composite rebars and beams include pre-tensioned and precisely positioned reinforcing fibers disposed within a cured polymer that enhance the mechanical properties of the rebars and beams.
  • At least one technical advantage of the disclosed techniques relative to the prior art is that the disclosed techniques enable fabrication of fiber-reinforced composite rebars and beams that have the mechanical properties of conventional composite rebars and beams having orders of magnitude more reinforcing fibers.
  • a further advantage is that the disclosed techniques enable fabrication of fiber- reinforced composite rebars and beams that include pre-tensioned reinforcing fibers that enhance the mechanical properties of the rebar and beams.
  • a method for fabricating a composite structural member includes: positioning each fiber strand included in one or more fiber strands at a respective location within a mold cavity of a polymer mold; exerting a tensile force on each fiber strand included in the one or more fiber strands; filling the mold cavity with a fluid that includes a polymer; and curing the fluid within the mold cavity while the tensile force continues to be exerted on each fiber strand included in the one or more fiber strands.
  • each respective location within the mold cavity comprises a location between an inner surface of the mold cavity and a center axis of the mold cavity.
  • filling the mold cavity with the fluid comprises causing the fluid to flow into the mold cavity as a cured segment of the composite structural member is removed from the mold cavity.
  • filling the mold cavity with the fluid comprises causing the fluid to flow into the mold cavity after a cured segment of the composite structural member has been removed from the mold cavity.
  • each fiber strand included in the one or more fiber strands comprises one of a single fiber and a braid of multiple fibers.
  • curing the fluid within the mold cavity comprises: performing a pre-curing process on the fluid within the mold cavity to form a pre-cured segment of the composite structural member; removing the pre-cured segment from the mold cavity; and after removing the pre-cured segment from the mold cavity, performing a surface shaping operation on the pre-cured segment.
  • the partial curing process comprises initiating polymerization of the fluid in a region of the mold cavity that corresponds to a core region of the composite structural member.
  • the partial curing process comprises causing polymerization of the fluid via at least one of microwaves directed to a center region of the mold cavity, ultra-violet rays directed to the center region of the mold cavity, or infra-red rays directed to the center region of the mold cavity.
  • aspects of the present embodiments may be embodied as a system, method or computer program product. Accordingly, aspects of the present disclosure may take the form of an entirely hardware embodiment, an entirely software embodiment (including firmware, resident software, micro-code, etc.) or an embodiment combining software and hardware aspects that may all generally be referred to herein as a “module,” a “system,” or a “computer.” In addition, any hardware and/or software technique, process, function, component, engine, module, or system described in the present disclosure may be implemented as a circuit or set of circuits. Furthermore, aspects of the present disclosure may take the form of a computer program product embodied in one or more computer readable medium(s) having computer readable program code embodied thereon.
  • the computer readable medium may be a computer readable signal medium or a computer readable storage medium.
  • a computer readable storage medium may be, for example, but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing.
  • a computer readable storage medium may be any tangible medium that can contain, or store a program for use by or in connection with an instruction execution system, apparatus, or device.
  • each block in the flowchart or block diagrams may represent a module, segment, or portion of code, which comprises one or more executable instructions for implementing the specified logical function(s).
  • the functions noted in the block may occur out of the order noted in the figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Composite Materials (AREA)
  • Textile Engineering (AREA)
  • Moulding By Coating Moulds (AREA)

Abstract

L'invention concerne un procédé permettant de fabriquer un élément structural composite (100) qui consiste : à positionner chaque brin de fibre (101) inclus dans un ou plusieurs brins de fibre à un emplacement respectif à l'intérieur d'une cavité de moule (430) d'un moule polymère (330) ; à exercer une force de traction sur chaque brin de fibre inclus dans le ou les brins de fibre ; à remplir la cavité de moule avec un fluide qui comprend un polymère ; et à durcir le fluide à l'intérieur de la cavité de moule tandis que la force de traction continue à être exercée sur chaque brin de fibre inclus dans le ou les brins de fibre.
PCT/US2024/035472 2023-06-26 2024-06-25 Techniques permettant de fabriquer des barres et des barres composites Ceased WO2025006501A1 (fr)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
US202363510332P 2023-06-26 2023-06-26
US63/510,332 2023-06-26
US18/752,642 2024-06-24
US18/752,642 US20240424753A1 (en) 2023-06-26 2024-06-24 Techniques for fabricating composite rebars and beams

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1387857A (fr) * 1963-10-03 1965-02-05 Profilés constitués de fils solidarisés au moyen d'un liant plastique rigide
US5096645A (en) * 1990-10-09 1992-03-17 Plastigage Corporation Method of forming reinforced thermoplastic members
US20030092524A1 (en) * 2001-11-13 2003-05-15 Baranda Pedro S. Elevator belt assembly with noise and vibration reducing grooveless jacket arrangement
WO2021244750A1 (fr) * 2020-06-04 2021-12-09 Toyota Motor Europe Pultrusion améliorée

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1387857A (fr) * 1963-10-03 1965-02-05 Profilés constitués de fils solidarisés au moyen d'un liant plastique rigide
US5096645A (en) * 1990-10-09 1992-03-17 Plastigage Corporation Method of forming reinforced thermoplastic members
US20030092524A1 (en) * 2001-11-13 2003-05-15 Baranda Pedro S. Elevator belt assembly with noise and vibration reducing grooveless jacket arrangement
WO2021244750A1 (fr) * 2020-06-04 2021-12-09 Toyota Motor Europe Pultrusion améliorée

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