Method for preparing and testing pultrusion plate splicing seam tensile sample strip for wind power blade

Abstract

The invention discloses a preparation and test method of a pultrusion plate splicing seam tensile spline for a wind power blade. The preparation tool comprises an electric heating platform, a spline pouring forming area and a vacuum exhaust hood. The sample strip pouring forming area is arranged in an area covered by the vacuum exhaust hood on the electric heating platform, and is formed by splicing pultrusion plates between the two pultrusion plates in a surrounding manner; a cushion block for preventing the two pultrusion plates from moving oppositely is arranged at each of the two ends of the pultrusion plate abutted seam, so that the pultrusion plate abutted seam can always meet the size requirement of a target abutted seam sample strip. Therefore, the technical problem that the gap of the splicing seam between existing pultrusion plates is not accurate can be solved.

Description

Technical Field

[0001] This invention relates to a method for preparing and testing tensile specimens of pultruded plate splice seams for wind turbine blades, belonging to the field of performance testing technology for wind turbine blades. Background Technology

[0002] In the wind turbine blade industry, testing of pultruded plate splice seams is currently considered a material-level test. During blade manufacturing, gaps may appear between pultruded plates due to improper placement or inadequate fiber fabric filling. These gaps can affect blade performance, necessitating the preparation of corresponding specimens for verification. The preparation of pultruded plate splice seam specimens typically involves leaving a certain distance between two pultruded plates (along the length direction) according to design requirements, laying fiberglass cloth on both sides of the pultruded plates, and then injecting resin into the sample using a vacuum infusion method. However, current technology suffers from drawbacks. During vacuum evacuation, pressure can cause the pultruded plates to shift towards the center of the splice seam, potentially leading to inaccurate seam distances. Furthermore, the fiberglass cloth on the upper surface of the pultruded plates can be dented due to pressure, resulting in discrepancies between the prepared sample and expectations, ultimately affecting the test results. Summary of the Invention

[0003] The purpose of this invention is to provide a method for preparing and testing splice seam templates for pultruded plates of wind turbine blades, so as to solve the technical problem of inaccurate gaps between splice seams of existing pultruded plates.

[0004] To achieve the above-mentioned technical objectives, the present invention will adopt the following technical solution:

[0005] A tooling for preparing a tensile template for a pultruded plate splice joint of a wind turbine blade includes an electric heating platform, a template injection forming area, and a vacuum extraction hood. The template injection forming area is located within the area covered by the vacuum extraction hood on the electric heating platform and is formed by surrounding the pultruded plate splice between two pultruded plates. At each end of the pultruded plate splice, a pad is placed to prevent the two pultruded plates from moving towards each other, so that the pultruded plate splice can always meet the size requirements of the target splice joint template.

[0006] Preferably, the pultruded plate joint is formed by surrounding the upper and lower surfaces of the two pultruded plates with fiberglass cloth to form a spline casting area; the four corners of the fiberglass cloth are fixed to the heating platform with sealing strips.

[0007] Preferably, a porous flow channel pad is arranged on the upper side of the spline injection molding area; the two ends of the porous flow channel pad can be respectively overlapped on two pultruded plates.

[0008] Preferably, the porous flow channel pad is a pad wrapped with a porous membrane.

[0009] Preferably, the vacuum hood is formed by laying a vacuum bag on an electrically heated platform.

[0010] Another technical objective of this invention is to provide a method for preparing a tensile test strip for the splice joint of a pultruded plate used in wind turbine blades. The method involves injecting resin into a splice joint test strip preparation fixture using a vacuum infusion method to obtain the target splice joint test strip. Specifically, the method includes the following steps:

[0011] Step 1: Apply a layer of release agent to the electric heating platform, and then lay the release cloth and fiberglass cloth on the electric heating platform in sequence. Fix the four corners of the fiberglass cloth to the electric heating platform with sealing strips.

[0012] Step 2: Lay two pultruded boards of the same size on the fiberglass cloth laid in Step 1, and ensure that the pultruded board joint between the two pultruded boards meets the size requirements of the target splice template;

[0013] Step 3: Place appropriately sized pads at both ends of the pultruded sheet joint;

[0014] Step 4: Lay fiberglass cloth and release cloth on top of the pultruded plate in sequence, and fix the four corners of the fiberglass cloth to the electric heating platform with sealing strips;

[0015] Step 5: Lay out a layer of vacuum bags to cover the entire pultruded plate area;

[0016] Step 6: Vacuum infusion of resin to obtain the pultruded plate splice template, which can then be cut to obtain the target splice template.

[0017] Preferably, in step four, a porous flow channel pad is also laid at the joint of the pultruded plate above the release fabric.

[0018] Preferably, the porous flow channel pad is a pad wrapped with a porous membrane.

[0019] Preferably, the fiberglass cloth laid in steps one and four each has two layers.

[0020] Another technical objective of this invention is to provide a test method for tensile test strips of pultruded plate splice joints for wind turbine blades, comprising the following steps:

[0021] Step A: Inspect the appearance of the target splice seam strip and select multiple valid samples that meet the appearance requirements;

[0022] Step B: Number and photograph the selected valid samples, and select three points within the test area of ​​the valid samples. Measure the width and thickness of each point with calipers and take the average value.

[0023] Step C: Vertically mount the effective specimen onto the tensile testing machine for testing, and calculate the stress of the corresponding effective specimen using the following formula:

[0024] ;

[0025] In the formula, Indicates stress; This indicates the load provided by the tensile testing instrument. This indicates the cross-sectional area of ​​the test zone of the valid sample.

[0026] Based on the above-mentioned technical objectives, the present invention has the following advantages compared with the prior art:

[0027] This invention requires first designing the dimensions of the pultruded plate splice seam template according to the testing needs, and then determining the required pultruded plate size based on the dimensions of the pultruded plate splice seam template. Spacers of the required pultruded plate splice seam size are placed at both ends along the length of the pultruded plate to prevent it from moving towards the center of the splice seam during vacuuming. When laying the fiberglass cloth, it needs to be fixed to the table surface with black adhesive around its edges. A paper flow channel pad wrapped with a porous membrane is placed on top of the last layer of fiberglass cloth, and then vacuuming is performed. This ensures that the fiberglass cloth will not be dented during vacuuming. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the tooling for preparing the splice seam template of the pultruded plate of the wind turbine blade according to the present invention;

[0029] In the diagram: 1. Heating platform; 2. Sealing strip; 3. Fiberglass cloth; 4. Pultruded plate; 5. Spacer block; 6. Flow channel plate; 7. Separating membrane; 8. Vacuum bag. Detailed Implementation

[0030] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention. Unless otherwise specifically stated, the relative arrangement, expressions, and values ​​of components and steps set forth in these embodiments do not limit the scope of the present invention. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values.

[0031] For ease of description, spatial relative terms such as "above," "over," "on the upper surface of," "above," etc., are used here to describe the spatial positional relationship of a device or feature as shown in the figure with other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation besides the orientation of the device as described in the figure. For example, if the device in the figure is inverted, a device described as "above" or "above" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations). Example 1

[0032] like Figure 1 As shown, this embodiment discloses a tooling for preparing a tensile template for the splice seam of pultruded plates for wind turbine blades. The tooling includes an electric heating platform, a template injection forming area, and a vacuum extraction hood. The vacuum extraction hood is formed by laying a vacuum extraction bag on the electric heating platform. The template injection forming area is located within the area covered by the vacuum extraction hood on the electric heating platform and is formed by surrounding the splice seam between two pultruded plates. In this embodiment, the pultruded plate splice seam is formed by surrounding the upper and lower surfaces of the two pultruded plates with fiberglass cloth. The four corners of the fiberglass cloth are fixed to the heating platform with sealing strips. A pad is placed at each end of the pultruded plate splice to prevent the two pultruded plates from moving towards each other, preventing the pultruded plates from moving towards the middle of the splice seam during vacuuming, ensuring that the pultruded plate splice always meets the dimensional requirements of the target splice seam template. To ensure that the fiberglass cloth is not dented during vacuuming, a porous flow channel pad is arranged on the upper side of the spline casting area. The two ends of the porous flow channel pad can be overlapped on two pultruded plates respectively. In this embodiment, the porous flow channel pad is a pad wrapped with a porous membrane. Example 2

[0033] This embodiment discloses a method for preparing a splice seam template for pultruded plates used in wind turbine blades. It is based on the tooling for preparing tensile templates for splice seams of pultruded plates used in wind turbine blades described in Embodiment 1, and includes the following steps:

[0034] Step 1: Cut the pultruded plate into two pieces of the same size according to the test requirements;

[0035] Step 2: Apply a layer of release agent to the heating platform, then lay a layer of release cloth and two layers of fiberglass cloth on the heating platform in sequence. Fix the four corners of each layer of fiberglass cloth to the heating platform with sealing strips.

[0036] Step 3: Lay two pultruded boards on the fiberglass cloth, with the length of the pultruded boards parallel. Place spacers of appropriate size at both ends of the joint between the two pultruded boards. In this test, the joint is 5mm, so spacers with a length of 5mm are placed.

[0037] Step 4: Lay two layers of fiberglass cloth and release cloth on top of the pultruded plate in sequence. Fix the four corners of each layer of fiberglass cloth to the heating platform with sealing strips.

[0038] Step 5: Place a flow channel pad wrapped with a porous membrane at the joint of the pultrusion plate above the release fabric;

[0039] Step 6: Cover the entire pultruded plate area with a layer of vacuum bags;

[0040] Step 7: Perform vacuum setup and injection to obtain the desired pultruded plate splice template;

[0041] Step 8: Using the splice seam as the center, with the 90° direction of the pultruded plate as the length direction and the 0° direction of the pultruded plate as the width direction, cut the pultruded plate splice seam strip with a length of 200±1mm and a width of 50±0.2mm to obtain the desired pultruded plate splice seam strip. Example 3

[0042] This embodiment discloses a test method for tensile test strips of pultruded plate splice joints for wind turbine blades, used to test the pultruded plate splice joint test strips obtained in Embodiment 2, specifically including the following steps:

[0043] 1. Inspect the appearance of the samples. Discard any samples with burrs, bubbles, or incorrect dimensions. Select 6 valid samples.

[0044] 2. Before testing, number and photograph the samples, measure the width and thickness of the strip with calipers, select three points in the test area, and take the average value.

[0045] 3. Select appropriate clamps for sample installation, and ensure the sample remains vertical after installation;

[0046] 4. Begin testing. Calculate the strength of this type of spline using the formula:

[0047] ;

[0048] In the formula:

[0049] —Stress, measured in megapascals (MPa);

[0050] —The corresponding load measured is in Newtons (N);

[0051] —Cross-sectional area of ​​the test area of ​​the sample, in square millimeters (mm2).

[0052] 5. After the test is completed, select the valid data for data processing.

[0053] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A tooling for preparing a tensile specimen for the splice joint of pultruded plates for wind turbine blades, comprising an electric heating platform, a specimen casting and forming area, and a vacuum hood; the specimen casting and forming area is located within the area covered by the vacuum hood on the electric heating platform and is formed by surrounding the splice joint between two pultruded plates; characterized in that, Each end of the pultruded plate joint is equipped with a pad to prevent the two pultruded plates from moving towards each other, so that the pultruded plate joint can always meet the size requirements of the target joint template.

2. The tooling for preparing tensile test strips for pultruded plate splice seams of wind turbine blades according to claim 1, characterized in that, The pultruded plate joint is formed by connecting the upper and lower surfaces of the two pultruded plates to form a spline casting area; the four corners of the fiberglass cloth are fixed to the heating platform with sealing strips.

3. The tooling for preparing tensile test strips for pultruded plate splice joints of wind turbine blades according to claim 2, characterized in that, A porous flow channel pad is arranged on the upper side of the spline casting area; the two ends of the porous flow channel pad can be respectively attached to two pultruded plates.

4. The tooling for preparing tensile test strips for pultruded plate splice seams of wind turbine blades according to claim 3, characterized in that, The porous flow channel pad is a pad wrapped with a porous membrane.

5. The tooling for preparing tensile test strips for pultruded plate splice joints of wind turbine blades according to claim 3, characterized in that, A vacuum hood is formed by laying a vacuum bag on an electrically heated platform.

6. A method for preparing a tensile specimen for splice joints of pultruded plates for wind turbine blades, comprising injecting resin into a splice joint specimen preparation fixture via vacuum infusion to obtain a target splice joint specimen, characterized in that... Specifically, the steps include the following: Step 1: Apply a layer of release agent to the electric heating platform, and then lay the release cloth and fiberglass cloth on the electric heating platform in sequence. Fix the four corners of the fiberglass cloth to the electric heating platform with sealing strips. Step 2: Lay two pultruded boards of the same size on the fiberglass cloth laid in Step 1, and ensure that the pultruded board joint between the two pultruded boards meets the size requirements of the target splice template; Step 3: Place appropriately sized pads at both ends of the pultruded sheet joint; Step 4: Lay fiberglass cloth and release cloth on top of the pultruded plate in sequence, and fix the four corners of the fiberglass cloth to the electric heating platform with sealing strips; Step 5: Lay out a layer of vacuum bags to cover the entire pultruded plate area; Step 6: Vacuum infusion of resin to obtain the pultruded plate splice template, which can then be cut to obtain the target splice template.

7. The method for preparing tensile test strips for splice seams of pultruded plates for wind turbine blades according to claim 6, characterized in that, In step four, a porous flow channel pad was also placed at the joint of the pultruded plate above the release fabric.

8. The method for preparing tensile test strips for splice seams of pultruded plates for wind turbine blades according to claim 7, characterized in that, The porous flow channel pad is a pad wrapped with a porous membrane.

9. The method for preparing tensile test strips for splice seams of pultruded plates for wind turbine blades according to claim 6, characterized in that, The fiberglass cloth laid in steps one and four each consists of two layers.

10. A test method for tensile test strips of pultruded plate splice joints for wind turbine blades, characterized in that, Includes the following steps: Step A: Inspect the appearance of the target splice seam strip and select multiple valid samples that meet the appearance requirements; Step B: Number and photograph the selected valid samples, and select three points within the test area of ​​the valid samples. Measure the width and thickness of each point with calipers and take the average value. Step C: Vertically mount the effective specimen onto the tensile testing machine for testing, and calculate the stress of the corresponding effective specimen using the following formula: ； In the formula, Indicates stress; This indicates the load provided by the tensile testing instrument. This indicates the cross-sectional area of ​​the test zone of the valid sample.

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