CN115492416A - FRP-SMA composite sheet and reinforcing method thereof - Google Patents

Abstract

The invention relates to an FRP‑SMA composite sheet and its reinforcement method, comprising at least two FRP sheets arranged side by side at intervals, memory alloy wires are connected between at least two FRP sheets, and each FRP sheet is In the material composite area, the memory alloy wire located between two adjacent FRP sheets is the prestress activation area. The memory alloy wire is connected with the FRP sheet through nylon wire. The invention has simple and reasonable structural design, convenient installation, simple application of prestress to components, greatly reduces the workload of technical personnel, reduces work difficulty, improves the ability of reinforcement and fully utilizes the performance of materials.

Description

A kind of FRP-SMA composite sheet and its strengthening method

Technical field:

The invention relates to an FRP-SMA composite sheet and a reinforcing method thereof.

Background technique:

At present, many FRP materials (fiber reinforced composite materials) are used for the reinforcement of wood structures. Although FPR materials can improve the mechanical properties of the structure, there are still defects, such as the performance of FRP materials is not fully utilized, and it is easy to occur when pasting FRP materials. The sheet peels off, so it is necessary to pre-tension the FRP material, but the current application is still at the stage of mechanical tension to generate pre-stress, and the construction is too complicated. Secondary stretching, the later stress loss cannot be supplemented again. And shape memory alloys (shape memory alloys, SMA) have shape memory effect and superelasticity, and it also has some applications in architectural structures, indicating that it can provide a restoring force, which is equivalent to prestress, and can be controlled by temperature way to control its resilience. Therefore, it is considered that SMA and FRP can work together to form a new type of composite material. It can actively control the prestress strength in the composite material. Under the reasonable planning in the early stage, after the reinforcement is completed, the temperature control can be used to improve the prestress relaxation in the later stage to achieve the secondary reinforcement effect, and there is no need for anchoring and tensioning systems during the reinforcement process. In terms of construction, resources can be used more rationally and the efficiency of material use can be optimized.

Invention content:

The purpose of the present invention is to provide a FRP-SMA composite sheet suitable for wood member reinforcement and its reinforcement method, which has a reasonable design, can greatly reduce the workload of technicians, reduce work difficulty, improve reinforcement capacity and fully utilize material properties.

In order to achieve the above object, the technical solution adopted by the present invention is: a FRP-SMA composite sheet, comprising at least two FRP sheets arranged side by side at intervals, at least two FRP sheets are connected with memory alloy wires, each Each FRP sheet is a material composite area, and the memory alloy wire located between two adjacent FRP sheets is a prestress activation area.

Further, the memory alloy wire is connected to the FRP sheet through a nylon wire.

Further, the memory alloy wires include several memory alloy wires distributed side by side at intervals, and the distribution direction of the several memory alloy wires is perpendicular to the distribution direction of at least two FRP sheets.

Further, each FRP sheet has two layers, and the material composite area is composed of two layers of FRP sheets and memory alloy wires, and the memory alloy wires and the two layers of FRP sheets are alternately interspersed and connected together with nylon threads.

Further, the distance between several memory alloy wires is 3mm-5mm; the length of the material composite area is 20mm-30mm, and the length of the prestress activation area is 5mm-15mm.

Another technical solution adopted in the present invention is: a method for reinforcing wooden beams using FRP-SMA composite sheets, comprising the following steps:

Step S1: Treat the surface of the wooden beam, remove the decayed part and fill it with materials, and clean the surface of other parts so that the FRP cloth can be firmly bonded to the wood;

Step S2: Support the position of the large deflection of the wooden beam, first restore the deformation, then use a layer of FRP cloth to pad the bottom of the beam, and then apply a layer of epoxy resin on the upper part, and then put the memory alloy wire The materials are arranged on the FRP cloth at a distance of 3 mm. In order to keep the position of the memory alloy wire fixed during operation, transparent adhesive tape is pasted on both ends of the memory alloy wire, and finally a layer of FRP cloth is covered at both ends and the middle. The FRP cloth is directly coated with epoxy resin glue on the bottom of the beam to achieve the effect of anchoring. After the epoxy resin is dry, remove the transparent tape;

Step S3: After the epoxy resin is dry, wrap a circle of FRP-SMA composite sheet at both ends and in the middle of the beam respectively, so that the material composite areas of the composite sheet are connected end to end, and the material composite area is covered with epoxy resin , so that the SMA-FRP composite sheet can be more tightly bonded to the beam, avoid peeling or slipping, and make the material properties of the memory alloy wire fully utilized;

Step S4: After the epoxy resin is dry, electrify the prestress activation area of the hoop-wound FRP-SMA composite sheet respectively to make it generate pretightening force to achieve the effect of strengthening anchorage; then memory the middle part of the beam The alloy wire is energized to generate a pre-tightening force, thereby resisting the tension at the bottom of the beam and repairing the tiny cracks at the bottom of the beam.

Another technical solution adopted by the present invention is: a method for reinforcing wooden columns using FRP-SMA composite sheets, comprising the following steps:

Step S1: Treat the surface of the wooden column, remove the decayed part and fill it with materials, and clean the surface of other parts so that the FRP cloth can be firmly bonded to the wood;

Step S2: First apply a circle of epoxy resin to the cracked part of the wooden column, wrap a circle with FRP cloth at the place where the epoxy resin is applied, and then cover the epoxy resin with the FRP cloth;

Step S3: Wrap the cracked part of the wooden column with the FRP-SMA composite sheet for one to three turns, so that the material composite areas of the FRP-SMA composite sheet are connected end to end, and then coat the material composite area with epoxy resin;

Step S4: After the epoxy resin is dried, electrify the prestress activation area of the FRP-SMA composite sheet to generate a pretightening force, thereby tightening the wooden column and repairing the damage.

Compared with the prior art, the present invention has the following effects: the present invention has simple and reasonable structural design, convenient installation, simple application of prestress to components, greatly reducing the workload of technicians, reducing work difficulty, improving the ability of reinforcement and making full use of materials performance.

Description of drawings:

Fig. 1 is a top view structural schematic view of an embodiment of the present invention;

Fig. 2 is a schematic diagram of a three-dimensional structure of an embodiment of the present invention;

Fig. 3 is the overall effect drawing of reinforcing wooden beam and wooden post in the embodiment of the present invention;

Fig. 4 is the structural representation of reinforcing wooden post in the embodiment of the present invention;

Fig. 5 is a side view structural schematic diagram of a reinforced square wooden beam in an embodiment of the present invention;

Fig. 6 is the bottom view structure schematic diagram of reinforcing square wooden beam in the embodiment of the present invention;

Fig. 7 is a schematic side view of a reinforced round wooden beam in an embodiment of the present invention.

In the picture:

1- FRP sheet; 2- memory alloy wire; 3- nylon wire; 101- material composite area; 201- prestress activation area.

detailed description:

The present invention will be described in further detail below in conjunction with the accompanying drawings and specific embodiments.

In describing the present invention, it should be understood that the terms "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", The orientations or positional relationships indicated by "horizontal", "top", "bottom", "inner", "outer", etc. are based on the orientation or positional relationships shown in the drawings, and are only for the convenience of describing the present invention, rather than indicating or It should not be construed as limiting the invention by implying that a referenced device or element must have a particular orientation, be constructed, and operate in a particular orientation.

As shown in Figures 1 to 2, a FRP-SMA composite sheet of the present invention includes at least two FRP sheets 1 and memory alloy wires 2 distributed side by side at intervals, and the memory alloy wires 2 are connected by nylon wires 3 at least Between two FRP sheets 1, the composite sheet is divided into a material composite area 101 and a prestress activation area 201 according to whether there is an FRP sheet 1, and the two areas are alternately arranged along the distribution direction of the FRP sheet, that is: each The location of one FRP sheet 1 is the material composite area 101 , and the location of the memory alloy wire 2 between two adjacent FRP sheets 1 is the prestress activation area 2021 .

In this embodiment, the FRP-SMA composite sheet includes but not limited to reinforced wooden beams and wooden columns.

In this embodiment, the memory alloy wire 2 includes several memory alloy wires distributed side by side at intervals, and the distribution direction of the several memory alloy wires is perpendicular to the distribution direction of at least two FRP sheets 1 .

In this embodiment, each FRP sheet has two layers, and the material composite area 101 is composed of two layers of FRP sheet and memory alloy wire; in the material composite area, memory alloy wire and two layers of FRP sheet Use nylon thread to alternately intersperse and connect together. The prestress activation area 201 is a memory alloy wire.

In this embodiment, the prestress activation area applies prestress to the component by heating the memory alloy wire 2 .

In this embodiment, the distance between several memory alloy wires is 3mm-5mm; the length of the material composite area is 20mm-30mm, and the length of the prestress activation area is 5mm-15mm.

It should be noted that the FRP sheet in this embodiment is a fiber reinforced composite material (Fiber Reinforced Polymer/Plastic, FRP for short), and the SMA is a shape memory alloy (shape memory alloys, SMA), which are all known technologies.

In this embodiment, when the FRP-SMA composite sheet is used to reinforce the wooden beam, the specific reinforcement method includes the following steps:

Step S1: Treat the surface of the wooden beam, remove the decayed part and insert it with a suitable material, and clean the surface of other parts so that the FRP cloth can be firmly bonded to the wood;

Step S2: Support the position of the large deflection of the wooden beam, first restore the deformation, then use a layer of FRP cloth to pad the bottom of the beam, and then apply a layer of epoxy resin on the upper part, and then put the memory alloy wire The materials are arranged on the FRP cloth at a distance of 3 mm. In order to keep the position of the memory alloy wire 2 fixed during operation, transparent adhesive tape is pasted on both ends of the memory alloy wire, and finally a layer of FRP cloth is covered on each end and the middle , the FRP cloth is directly coated with epoxy resin glue on the bottom of the beam to achieve the anchoring effect, and the transparent adhesive cloth is removed after the epoxy resin is dry;

Step S3: After the epoxy resin is dry, wrap a circle of FRP-SMA composite sheet in the two ends and the middle of the beam, respectively, so that the material composite area 101 of the composite sheet is connected end to end, and the material composite area 101 is fully coated with rings. Oxygen resin, so that the SMA-FRP composite sheet can be more tightly bonded to the beam, avoiding peeling or slipping, so that the material properties of the memory alloy wire can be fully utilized;

Step S4: After the epoxy resin is dry, electrify the prestress activation area of the hoop-wound FRP-SMA composite sheet respectively to make it generate pretightening force to achieve the effect of strengthening anchorage; then memory the middle part of the beam The alloy wire is energized to generate a pre-tightening force, thereby resisting the tension at the bottom of the beam and repairing the tiny cracks at the bottom of the beam.

In this embodiment, when the FRP-SMA composite sheet is used to reinforce the wooden column, the specific reinforcement method includes the following steps:

Step S1: Treat the surface of the wooden column, remove the decayed part and insert it with a suitable material, and clean the surface of other parts so that the FRP cloth can be firmly bonded to the wood;

Step S2: First apply a circle of epoxy resin to the cracked part of the wooden column, wrap a circle with FRP cloth at the place where the epoxy resin is applied, and then cover the epoxy resin with the FRP cloth;

Step S3: Wrap the cracked part of the wooden column with FRP-SMA composite sheet for one to three times as appropriate, so that the material composite areas of the FRP-SMA composite sheet are connected end to end, and then coat the material composite area with epoxy resin;

Step S4: After the epoxy resin is dried, electrify the prestress activation area of the FRP-SMA composite sheet to generate a pretightening force, thereby tightening the wooden column and repairing the damage.

If the present invention discloses or relates to parts or structural parts that are fixedly connected to each other, then, unless otherwise stated, the fixed connection can be understood as: a detachable fixed connection (for example, using bolts or screws), or it can also be understood as: Non-detachable fixed connection (such as riveting, welding), of course, the mutual fixed connection can also be replaced by an integrated structure (such as manufactured by integral forming by casting process) (except that the integral forming process cannot be adopted obviously).

In addition, unless otherwise stated, the terms used in any of the technical solutions disclosed in the present invention to indicate positional relationships or shapes include states or shapes that are similar, similar or close to them.

Any component provided by the present invention can be assembled from multiple individual components, or can be a single component manufactured by integral forming process.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them; although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that: the present invention can still be Modifications to the specific implementation of the invention or equivalent replacement of some technical features; without departing from the spirit of the technical solution of the present invention, should be included in the scope of the technical solution claimed in the present invention.

Claims (7)

1. A FRP-SMA composite sheet, characterized in that: comprise at least two FRP sheets arranged side by side at intervals, at least two FRP sheets are connected with a memory alloy wire, and each FRP sheet is a material In the composite area, the memory alloy wire located between two adjacent FRP sheets is the prestress activation area. 2. A FRP-SMA composite sheet according to claim 1, characterized in that: the memory alloy wire is connected to the FRP sheet through a nylon thread. 3. A kind of FRP-SMA composite sheet material according to claim 1 or 2, is characterized in that: described memory alloy wire comprises several memory alloy wires that are spaced side by side, and the distribution direction of several memory alloy wires is in line with The distribution directions of at least two FRP sheets are perpendicular to each other. 4. A kind of FRP-SMA composite sheet material according to claim 3, is characterized in that: every sheet FRP sheet material is two-layer, and described material composite area is made up of two-layer FRP sheet material and memory alloy wire material, Memory alloy wires and two layers of FRP sheets are alternately interspersed with nylon threads. 5. A kind of FRP-SMA composite sheet material according to claim 3, is characterized in that: the spacing of several memory alloy wires is 3mm-5mm; The length of the material composite area is 20mm-30mm, and the prestressed The length of the activation area is 5mm-15mm. 6. A method for reinforcing wooden beams by using the FRP-SMA composite sheet as described in any one of claims 1 to 5, characterized in that: comprising the steps: Step S1: Treat the surface of the wooden beam, remove the decayed part and fill it with materials, and clean the surface of other parts so that the FRP cloth can be firmly bonded to the wood; Step S2: Support the position of the large deflection of the wooden beam, first restore the deformation, then use a layer of FRP cloth to pad the bottom of the beam, and then apply a layer of epoxy resin on the upper part, and then put the memory alloy wire The materials are arranged on the FRP cloth at a distance of 3 mm. In order to keep the position of the memory alloy wire fixed during operation, transparent adhesive tape is pasted on both ends of the memory alloy wire, and finally a layer of FRP cloth is covered at both ends and the middle. The FRP cloth is directly coated with epoxy resin glue on the bottom of the beam to achieve the effect of anchoring. After the epoxy resin is dry, remove the transparent tape; Step S3: After the epoxy resin is dry, wrap a circle of FRP-SMA composite sheet at both ends and in the middle of the beam respectively, so that the material composite areas of the composite sheet are connected end to end, and the material composite area is covered with epoxy resin , so that the SMA-FRP composite sheet can be more tightly bonded to the beam, avoid peeling or slipping, and make the material properties of the memory alloy wire fully utilized; Step S4: After the epoxy resin is dry, electrify the prestress activation area of the hoop-wound FRP-SMA composite sheet respectively to make it generate pretightening force to achieve the effect of strengthening anchorage; then memory the middle part of the beam The alloy wire is energized to generate a pre-tightening force, thereby resisting the tension at the bottom of the beam and repairing the tiny cracks at the bottom of the beam. 7. A method for reinforcing wooden columns by using the FRP-SMA composite sheet as described in any one of claims 1 to 5, characterized in that: comprising the steps: Step S1: Treat the surface of the wooden column, remove the decayed part and fill it with materials, and clean the surface of other parts so that the FRP cloth can be firmly bonded to the wood; Step S2: First apply a circle of epoxy resin to the cracked part of the wooden column, wrap a circle with FRP cloth at the place where the epoxy resin is applied, and then cover the epoxy resin with the FRP cloth; Step S3: Wrap the cracked part of the wooden column with the FRP-SMA composite sheet for one to three turns, so that the material composite areas of the FRP-SMA composite sheet are connected end to end, and then coat the material composite area with epoxy resin; Step S4: After the epoxy resin is dried, electrify the prestress activation area of the FRP-SMA composite sheet to generate a pretightening force, thereby tightening the wooden column and repairing the damage.

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