A high-grammage, high-modulus multiaxial fabric for circumferential layup of wind turbine blades and its preparation method.

Abstract

This invention relates to the field of fiberglass product technology. Addressing the problems of substandard raw material performance and slow layup efficiency caused by the increasing size of wind turbine blades, it provides a high-weight, high-modulus multiaxial fabric for circumferential layup of wind turbine blades and its preparation method. The fabric includes 90° yarn, ±n° oblique weft yarn, 0° fine yarn, and stitching thread, wherein 30≤n≤60; the weight percentage of 0° fine yarn is 0.1%-1%, the weight percentage of 90° yarn is 32%-34%, and the weight percentage of ±n° oblique weft yarn is 32%-34%. Through the setting and optimization of the four-directional yarns, the mechanical advantages of high modulus and high weight can be fully utilized, while solving the molding difficulties after the introduction of 90° yarn. This allows the resulting fabric product to be adapted to the automated layup process of wind turbine blades, reducing manual trimming processes caused by yarn defects, improving blade manufacturing efficiency, strengthening the structural stability of the circumferential layup, extending the fatigue life of the blade, and reducing the total life cycle cost.

Description

Technical Field

[0001] This invention relates to the field of glass fiber products technology, and more specifically, to a high-grammage, high-modulus multiaxial fabric for circumferential lay-up of wind turbine blades and its preparation method. Background Technology

[0002] As the core component for capturing wind energy, the size and performance of wind turbine blades directly determine the power generation efficiency and safety stability of the unit. With blade lengths exceeding 100 meters, the demand for circumferential load-bearing capacity has increased dramatically. Traditional layup materials, due to insufficient strength, modulus, or molding efficiency, have gradually become a bottleneck restricting the upgrading of blade performance. Developing high-performance reinforcing fabrics suitable for circumferential layups is therefore urgently needed.

[0003] Currently, the commonly used reinforcing materials for wind turbine blade layups mainly include unidirectional fabrics, bidirectional woven fabrics, and ordinary triaxial fabrics. While unidirectional fabrics exhibit excellent unidirectional mechanical properties, their circumferential shear resistance is weak, requiring multidirectional layering to compensate. This leads to cumbersome production processes, significant material waste, and poor interlayer bonding, making them prone to peeling failure. Although bidirectional woven fabrics possess a certain bidirectional load-bearing capacity, their modulus is generally low due to weaving structure limitations. Under the enormous centrifugal forces and aerodynamic loads experienced in the circumferential direction of the blade, they are prone to excessive deformation, affecting the aerodynamic stability of the blade.

[0004] Ordinary triaxial fabrics improve shear resistance by introducing a third directional yarn, but existing products often have a low basis weight (usually below 1000 g / m²). 2 One issue is the low utilization rate of high-modulus fibers. To meet circumferential load-bearing requirements, multiple layers need to be stacked, which not only increases the labor intensity and production cycle of blade forming but also reduces the overall structural reliability due to the increased interlayer interfaces. Furthermore, under harsh operating conditions such as offshore wind power, blades must withstand complex environmental erosion such as salt spray and strong winds, placing higher demands on the environmental stability and mechanical durability of the fabric. Existing materials struggle to balance high basis weight, high modulus, and process adaptability.

[0005] Therefore, in response to the special requirements of circumferential layup of wind turbine blades, there is an urgent need to develop a triaxial fabric with high basis weight, high modulus and good formability, so as to effectively reduce the number of layup layers and improve production efficiency, while strengthening the circumferential load-bearing capacity and structural stability of the blades. This has important practical significance and engineering value for promoting the development of wind power equipment towards high power and long service life. Summary of the Invention

[0006] The purpose of this invention is to provide a high-grammage, high-modulus multiaxial fabric for circumferential layup of wind turbine blades and its preparation method, so as to effectively solve the problems of substandard raw material performance and slow layup efficiency caused by the large size of blades.

[0007] This invention is achieved through the following technical solution: A high-grammage, high-modulus, multi-axial fabric for circumferential lay-up of wind turbine blades is constructed using E7 high-modulus glass fiber to form a multi-axial structure, specifically including 0° yarn, 90° yarn, ±n° (30≤n≤60) oblique weft yarn and stitching thread.

[0008] Preferably, the 0° fine yarn is EC9-68*766 specification yarn with a weight range of 1-3 g / m. 2 The 90° yarn uses E7DR17-2400-390 specification yarn, with a weight range of 440-468 g / m². 2 The ±n° bias weft yarn uses E7DR13-300-390 specification yarn, with a weight range of 440-468 g / m². 2 The weft laying method is parallel weft laying.

[0009] Preferably, based on the differences in the load-bearing function of yarns in each direction, the weight ratio is customized to achieve precise and targeted performance optimization. Specifically, the weight ratio of 0° yarn is 0.1%-1%, the weight ratio of 90° yarn is 32%-34%, and the weight ratio of ±n° oblique weft yarn is 32%-34%. Among them, the 90° yarn ensures the circumferential core load-bearing requirements with a high weight ratio, the 0° yarn improves radial stability with an appropriate weight ratio, and the ±n° oblique weft yarn strengthens shear performance with a balanced weight ratio. Ultimately, the in-plane shear strength of the fabric is significantly improved compared to traditional triaxial fabrics of the same weight ratio. According to the ASTM D7078 / D7078M test standards, under normal temperature test conditions, the in-plane shear strength of the fabric proposed in this invention can reach 230MPa, and the mechanical properties in each direction are precisely matched with the stress requirements of the circumferential layup.

[0010] Preferably, a highly efficient resin impregnation channel is constructed by precisely controlling the yarn arrangement gap. Specifically, the ±n° oblique weft yarn arrangement density is 1214 ends / inch, with the yarns arranged without gaps; the 90° yarn arrangement density is 8-10 ends / inch, with the yarns arranged without gaps; the 0° fine yarn arrangement density is 4-6 ends / inch, with a yarn spacing of 30.00-31.00 mm. Within the defined range of the arrangement density and spacing of the four-directional yarns, a continuous and interconnected resin flow channel can be formed inside the fiber layer, thereby specifically solving the defects such as resin impregnation dead corners and dry spots that are prone to occur in high-grammage multidirectional yarn fabrics. This ensures that the resin can quickly and evenly penetrate into the gaps between the yarns in each direction, taking into account both the performance of the yarn's mechanical properties and the quality of the fabric formation.

[0011] This invention innovatively adds a 0° radial load-bearing yarn, forming a four-axis yarn collaborative stress system consisting of a 90° circumferential main load-bearing yarn, a 90° radial anti-distortion yarn, and ±n° oblique shear-resistant yarns. This design can precisely match the complex stress requirements of tension-torsion composite and local compression in the circumferential layup of wind turbine blades (such as the root and flange connection areas), solving the problem of insufficient shear and distortion resistance and easy layup slippage caused by the lack of radial yarns in traditional fabrics.

[0012] Polyester yarn is also used as the stitching thread. The stitching thread is used to stitch together 90° yarn, ±n° bias weft yarn and 0° fine yarn through a chain stitching method. The stitching thread is 100D, the stitch density is 4-8 ends / inch, the stitch length is 2.5-3.5mm, and the weight range is (8±2) g / m³. 2 .

[0013] The present invention proposes a high-grammage, high-modulus, multi-axial fabric for circumferential layup of wind turbine blades, with a total fabric grammage ranging from 1313 to 1413 g / m³. 2 .

[0014] The high-weight, high-modulus multi-axis fabric proposed in this invention has a 90° tensile modulus that is more than 30% higher than that of conventional E6 transverse triaxial fabrics, and can exceed 36GPa. By designing the angle of the oblique yarns differently, that is, the angle of the oblique weft yarns is 30° to 60°, a three-dimensional resin flow channel is constructed, which significantly improves the wetting speed of the fabric.

[0015] This high-grammage, high-modulus multiaxial fabric can reduce the number of circumferential lay-up layers, resulting in a weight reduction of over 3 tons for a single 120-meter blade, while also reducing resin usage.

[0016] The technical solution of the present invention has at least the following advantages and beneficial effects: (1) In the high-weight, high-modulus multi-axis fabric proposed in this invention, by setting and optimizing the four-way yarn, the mechanical advantages of high modulus and high weight can be fully utilized, and the forming problem after the introduction of 90° yarn can be solved. This makes the fabric products suitable for the automated layup process of wind turbine blades, reduces the manual trimming process caused by yarn defects, improves the blade manufacturing efficiency, strengthens the structural stability of the circumferential layup, extends the fatigue life of the blade, and reduces the total life cycle cost.

[0017] (2) In view of the need for continuity and consistency of circumferential ply of blades, the present invention adopts a laying equipment with fabric width and roll length that is compatible with the fabric width and roll length, reduces splicing seams and stress concentration, improves overall circumferential strength and fatigue life, and is suitable for the manufacturing of large blades. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the morphological structure of the high-grammage, high-modulus multiaxial fabric used for circumferential layup of wind turbine blades in this invention. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, they are performed according to conventional conditions or conditions recommended by the manufacturer; where the manufacturers of the instruments, equipment, reagents, or raw materials used are not specified, they are all conventional products that can be purchased commercially.

[0020] Example 1

[0021] This embodiment prepares a high-grammage, high-modulus multiaxial fabric for circumferential layup of wind turbine blades, comprising 0° yarn, 90° yarn, ±45° yarn and stitch braided yarn, with the weight distribution being 0.1% for the 0° yarn layer, 33.1% for the 90° yarn layer, 33.1% for the ±45° yarn layer, and the remainder being stitch braided yarn.

[0022] The 0° fine yarn is made of EC9-68*766 specification E7 high-modulus glass fiber yarn with a weight of 2g / m. 2 The 90° yarn is made of E7 high-modulus glass fiber yarn with specifications E7DR17-2400-390 and a weight of 860g / m. 2 The ±45° twill weft yarn is made of E7DR13-300-390 high-modulus glass fiber yarn with a weight of 251g / m². 2 The stitching thread is made of 100D polyester yarn with a weight of 8g / m². 2 .

[0023] The specific preparation process is as follows: Step 1: Take 0° yarn, 90° yarn, ±45° yarn and sewing thread for later use, and spread them out in a four-axis spatial arrangement. The 0° yarn is arranged along the circumferential main bearing direction, the 90° yarn is arranged along the radial anti-distortion direction, and the ±45° oblique weft yarn is arranged symmetrically along the shear force direction. Check and ensure that the yarns in each direction are spread out flat, have uniform tension, and are free from tangling or deviation.

[0024] Step 2: Adjust the 0° yarn arrangement density to 5 ends / inch and the yarn spacing to 30.48 mm; set the 90° yarn arrangement density to 8.9 ends / inch and use a non-interval arrangement method; set the ±45° oblique weft yarn arrangement density to 14.8 ends / inch and use a non-interval parallel weft laying method.

[0025] Step 3: Use a stitching machine to stitch and bind the spread multi-axial yarn layer. The stitching method is chain stitching, the stitching density is set to 6 ends / inch, and the stitch length is controlled to 3.0mm. The 0° yarn, 90° yarn, and ±45° oblique weft yarn are tightly stitched together to form a continuous multi-axial fabric blank. During the stitching process, ensure that the stitches are uniform and there are no defects such as missed stitches or skipped stitches.

[0026] Step 4: Finish the surface of the sewn fabric blank, remove surface fuzz and filaments, and then roll it up to the required length according to the width and roll length requirements of the wind turbine blade layup equipment to obtain the finished product of high-grammage high-modulus multi-axis fabric for circumferential layup of wind turbine blades.

[0027] Comparative Example 1 The difference between this comparative example and Example 1 is that the weight percentage of the 0° yarn layer is 7.5%, the weight percentage of the 90° yarn layer is 51.5%, and the weight percentage of the ±45° yarn layer is 19.5% each, with the remainder being stitching yarn.

[0028] Comparative Example 2 This comparative example is an E6 transverse triaxial fabric, including transverse triaxial angles of +45°, 90°, and -45°, which is commonly referred to as TTX in the art.

[0029] Comparative Example 3 This comparative example is an E6 longitudinal triaxial fabric, including longitudinal triaxial angles of 0°, +45°, and -45°, which is usually referred to as TLX in the art.

[0030] Test case Samples: Example 1 and Comparative Examples 1-3 (1) Mechanical properties According to ASTM D7078 / D7078M "Test Method for Shear Properties of Composite Materials", tests were conducted using a universal electronic testing machine at room temperature. The results are summarized in Table 1 below: Table 1. Shear performance test results of different samples As shown in Table 1, the tensile strength of the fabric prepared in Example 1 continuously increased with the continuous balancing of basis weight in all directions, and the in-plane shear strength reached 246.6 MPa, which is significantly higher than that of conventional multiaxial fabrics in Comparative Examples 1-3. This demonstrates that the present invention, based on the continuous balancing of basis weight in all directions, can effectively improve the in-plane shear strength of the prepared fabric.

[0031] Another sample was taken, and tensile tests were performed according to ISO 527-4:2021 standard, with tensile strength and tensile modulus determined on a tensile testing machine; compression tests were performed according to ISO 14126:1999 standard, with compressive strength and compressive modulus determined on a compression testing machine; shear tests were performed according to ASTM D7078 / D7078M-20 standard, with shear modulus and shear strength determined. The results are summarized in Table 2 below: Table 2. Mechanical property test results of different samples As shown in Tables 1 and 2, the mechanical properties of the sample in Example 1 are far superior to those of Comparative Examples 1-3. In particular, Example 1, due to its weight ratio in each direction being within the optimal range of this invention, has a 90° tensile modulus of 37.2 GPa, which is more than 30% higher than that of the E6 transverse triaxial fabric in Comparative Example 2. Its in-plane shear strength is 246.6 MPa and its shear modulus is 7.5 GPa. The mechanical properties in each direction are precisely matched with the complex stress requirements of the circumferential layup of wind turbine blades. The 90° tensile strength of Example 1 is above 900 MPa and the 0° compressive strength is above 180 MPa, which can meet the usage requirements of large wind turbine blades of 100 meters or more.

[0032] (2) Wetting performance The resin penetration rate test method was adopted, using epoxy resin, commonly used in wind turbine blade manufacturing, as the wetting medium. Under standard atmospheric pressure at 25℃, the penetration distance and time of the resin in each sample fabric were tested, and the wetting rate was calculated. Three samples were tested for each group, and the average value was taken. The results are summarized in Table 3 below: Table 3. Calculation results of infiltration rate tests for different samples As shown in Table 3, the wetting rate of the fabric in Example 1 is more than 40% higher than that of the conventional fabrics in Comparative Examples 1-3. Moreover, the resin penetrates evenly inside the fabric without defects such as wetting dead corners or dry spots. This is due to the continuous resin flow channel constructed by the yarn arrangement gap precisely controlled by the present invention.

[0033] (3) Layup efficiency A 120-meter-class wind turbine blade was selected as the test object. Circumferential layup process experiments were conducted using the high-weight, high-modulus multiaxial fabric of Example 1 of this invention and the conventional E6 transverse triaxial fabric of Comparative Example 2. The number of layup layers, layup time, finished blade weight, and resin usage were statistically analyzed. The results are as follows: 3.1 Number of lay-up layers: The fabric of Example 1 requires only 30 lay-up layers, while the fabric of Comparative Example 2 requires 40 lay-up layers, reducing the number of lay-up layers by 25%; 3.2 Layup time: The total layup time of the fabric in Example 1 was 86 hours, while the total layup time of the fabric in Comparative Example 2 was 118 hours, representing a 27.1% improvement in layup efficiency; 3.3 Blade weight reduction: The finished blade made using the fabric of Example 1 weighed 85.6 tons, while the finished blade made using the fabric of Comparative Example 2 weighed 88.8 tons. The weight reduction per blade was 3.2 tons, which is more than 3 tons. 3.4 Resin usage: The resin usage of the fabric in Example 1 was 21.5 tons, and the resin usage of the fabric in Comparative Example 2 was 23.4 tons. The resin usage was reduced by 8.1%, which is in line with the design target of 8%.

[0034] As can be seen from the above experiments, the use of the high-weight, high-modulus multiaxial fabric for circumferential layup of wind turbine blades in Example 1 can significantly reduce the number of circumferential layup layers, reducing the weight of a single 120-meter blade by more than 3 tons, while also significantly reducing the amount of resin used.

[0035] This invention provides a high-grammage, high-modulus multiaxial fabric for circumferential layup of wind turbine blades and its preparation method. It can effectively solve the problems of substandard raw material performance and slow layup efficiency caused by the large size of blades, and provide technical support for the fine design of wind turbine blades, improve blade production efficiency, reduce blade weight, and especially for the design and development of ultra-large blades.

[0036] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A high-grammage, high-modulus, multi-axial fabric for circumferential layup of wind turbine blades, characterized in that, Includes 0° fine yarn, 90° yarn, ±n° oblique weft yarn and stitch braiding yarn, wherein 30≤n≤60; The weight percentage of 0° fine yarn is 0.1%-1%, the weight percentage of 90° yarn is 32%-34%, and the weight percentage of ±n° oblique weft yarn is 32%-34%. The 0° yarn arrangement density is 4-6 ends / inch, and the yarn spacing is 30.00-31.00 mm; the 90° yarn arrangement density is 8-10 ends / inch, and the yarns are arranged in an alternating pattern; the ±n° oblique weft yarn arrangement density is 12-14 ends / inch, and the yarns are arranged without spacing. The total weight of the high-weight, high-modulus, multi-axial fabric used for the circumferential layup of the wind turbine blades is 1313-1413 g / m². 2 The 90° yarn uses E7DR17-2400-390 specification yarn, and the ±n° oblique weft yarn uses E7DR13-300-390 specification yarn.

2. The high-grammage, high-modulus multiaxial fabric for circumferential layup of wind turbine blades according to claim 1, characterized in that, 0° fine yarn uses EC9-68*766 specification yarn with a weight of 1-3g / m². 2 .

3. The high-grammage, high-modulus multiaxial fabric for circumferential layup of wind turbine blades according to claim 1, characterized in that, 90° yarn weight is 440-468 g / m 2 .

4. The high-grammage, high-modulus multiaxial fabric for circumferential layup of wind turbine blades according to claim 1, characterized in that, ±n° bias weft yarn weight is 440-468g / m 2 .

5. The high-grammage, high-modulus multiaxial fabric for circumferential layup of wind turbine blades according to claim 1, characterized in that, The weight of the sewing thread is (8±2) g / m 2 .

6. A method for preparing a high-grammage, high-modulus multiaxial fabric for circumferential layup of wind turbine blades as described in any one of claims 1 to 5, characterized in that, The chain is made using braided thread with a braiding density of 4-8 ends / inch and a stitch length of 2.5-3.5mm.

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