DK153675B - PROCEDURE FOR MANUFACTURING USE OF A FOAM FABRIC STRENGTHED FIBER ARMED FORM SUCH AS WINGS OR ROTOR LEAVES WITH LARGE LENGTH AND WIDTH DIMENSIONS - Google Patents

Description

in

DK 153675 B

The invention relates to a method of the kind set out in the preamble of claim 1. Methods are known for making blades for gliders etc. i.e. for relatively small structural elements. In these known methods, the molds used must be closed so that costly manufacturing material is required to provide beam structures. In the case of rib constructions, adjustment problems arise, and in addition there is no possibility of control during manufacture.

The known methods are unsuitable only for the production of large molds, for example because of the poor relationship between mass and stiffness. rotor blades for large wind power plants and more.

Thus, the known constructions and methods are useless in the manufacture of blades or rotor blades with large surfaces, because they can neither be used to provide beam structures nor to make shell structures with prefabricated foam cores.

20 For beam structures, the pulp is greater at a given stiffness than for shell structures and the shapes must be able to close due to the contour accuracy of the thin-walled shell, whereby the connection between the beams and the exterior must be provided via small, difficult-to-control adhesive surfaces.

Shell structures with prefabricated foam core have the following shortcomings in the present case:

Due to its size and its costly geometric design, the foam core cannot be economically produced and a good quality connection between the core and the shell can only be achieved by the "wet-in-wet method" with closed molds.

2

DK 153675B

Also, this known method is unsuitable for the proposed purpose due to the large amount of laminate and the costly molding tools, especially because the total amount of laminate must be wet at the same time. The adhesion 5 of a core with hardened shells cannot be controlled.

Also, the known method for making shell structures with ribs has serious shortcomings, the total mass of the finished structure being increased too much at the rib mass and the mass of the connecting elements between the ribs and the shell. Furthermore, the fit of the ribs between the shells is very expensive. Furthermore, complete control of the adhesive is not possible.

The present invention has for its object to provide a method of the kind specified which does not deal with the aforementioned shortcomings of the known methods and by means of which, in separate, open molds, large blades or large rotor blades can be produced on a in such a way that during manufacture, the internal structure can be continuously checked and 20 errors corrected. This is achieved in a surprisingly simple manner and permits equal means by the measures specified in the claims.

In the following, the invention is explained in more detail with reference to the drawing, in which fig. 1 is a partial cross-sectional view of a large rotor blade manufactured according to the invention; FIG. 2 is a perspective view of a suction-pressure side shell for preparing the embodiment of FIG. 1; FIG. 3 shows the inner structure of the rotor blade arranged in the side shell,

DK 153675 B

3 FIG. 4 is a partial cross-sectional view of a foam core and backside foam fabric with oversize; FIG. 5 is a partial cross-sectional view of FIG. 4 after machining for completion, and 5 fig. 6 partial cross sections in two rotor blade parts during disassembly joining.

In FIG. 1, a fully-formed plastic body 10, in the form of a large rotor blade made according to the method according to the invention, is shown as follows: 10 first, an outer rotor blade shell 11 is laminated as a mold consisting of two separate half-parts 10a and 10b of a fiber-reinforced composite material, after which the shell II is hot or cold hardened, with large body molds preferably hot hardened due to the long processing time of the cold hardening. The lower torsion half of the shell 10b, as shown in FIG. 2 shows an outer diagonal laminate layer and a corresponding inner layer 14 and a unidirectional laminate layer 12 located therebetween for absorbing the bending forces resulting from bending and from the centrifugal force. The unidirectional laminate layer 12, which extends throughout the length of the blade, may be distributed over the overall profile cross-section or may be laminated only in certain areas. These areas are dependent on the expected load and the forces to be absorbed, respectively. The thickness and location depend on the masses needed, the stiffness, the strength and the center of gravity. Most often, e.g. in the back area of the profile, the so-called tab, a lightweight structure. To this end, the invention proposes a self-supporting sandwich structure. The proposed laminates can usually be made by the hand lamination method or as. so-called prepregs or even after vacuum injection.

DK 153675B

The 4 jection method.

FIG. 2 illustrates the manufacturing process and the suction pressure side shell structure, the outer shell layer of the blade being laid on a forming table 100 and laminated.

FIG. 3 shows the structure of the inner parts of a blade or wing and the manufacture of the so-called foam core, respectively. Also the core is made of two halves in each half of the laminating mold 100.

The foam core halves may be composed of rod-shaped foam elements 15a, i.e. of sheet material with a thickness of approx. 80 cm, forming slices and glued together. The slices correspond to the inner contour of the laminated shell half. The exact contour can be obtained by fitting, with each preceding foam disc or each prior rod shaped foam element 15a serving as a template for a next coarse slit, which is closed by a foamable adhesive. In this way, a closed foam core is obtained, which is only to be processed in the separator plane 21, fig. 4. This is true for both mold body parts 10a and 10b. The protruding foam parts at 15 and 17, fig. 4, is separated by a controlled cutting means. The wing or blade halves thus processed, i.e. the upper shell 10a and the lower shell 10b 25 are adhered to each other by means of their common separation plane 21.

The manufacturing process proceeds as follows: In the lamination mold for the lower mold half 10b, also called the undercoat, and in the lamination mold 30 for the upper mold half half 10a, also called over the shell, the outer lamination layer of the sheet is made of

DK 153675B

5 shows a composite fiber material in diagonal laminate, after which the laminate layer 12 is applied in the total length of the mold body and either over the entire profile section or only in sub-regions thereof. Then, in the area of the profile tab, foam sheets 13 are fitted which are adapted, after which the inner 3 laminate layer 14 is laminated. Also this layer 14 is a diago nal laminate and consists of a composite fiber material.

The inner core portion of the blade or rotor blade is manufactured for both halves by the same method: the foam bar is made of single foam bar elements 15a, the upper edge of which protrudes above the so-called separating plane 21. Next, these elements are adhered as shown in FIG. 3 on the torsion shell 11, 12, 13, 14 or inserted, and the end edge laminate 16 is milled in the tab area.

15 On the milling area 16, foam sheets 17, which also protrude outside the dividing plane 21. are adhered to, by means of a controlled cutting or milling means, foam parts 15 are cut or milled and the foam sheets 17 placed at the trailing edge exactly in the separating plane 21. Next, laminating 20 is inserted respectively 18 and a trailing edge web 19 immediately prior to joining the two mold body half portions 10a, 10b. Finally, stiffening angles 20 are adhered to ensure effective fixation and retention of the rod-shaped foam elements 15a in their proper position.

FIG. 6 shows the working stage immediately before the joining of the two mold body halves 10a, 10b. A foam adhesive is applied to all surfaces of the parts 10a, 10b and 19 on the parting plane, after which 30 the two mold body halves are joined together. The cure during which the lamination processes are discussed above.

The curing and drying time of adhesive is dependent on the nature of the foam adhesive used.

Claims (6)

A method of producing, by means of a foam core (15), stiffened, fiber-reinforced plastics mold bodies (10) such as blades or rotor blades with large length and width dimensions in open molds, wherein the mold body (10) is to be laminated (11) and cured in two separate shell halves (11a, 11b) of a laminated fiber material, characterized in that a) the foam core (15) is made directly in each of the two shell halves (11a, 11b) by being composed of transversely longitudinally extending and adhering ribbed foam elements (15a) along the longitudinal direction of the mold body, and b) the mold body half portions (10a, 10b) filled with the foam core are planed in their separating planes (21) and bonded thereto. The method according to claim 1, characterized in that the material of the foam core (15) is connected to the shell half portions (11a, 11b). Method according to claims 1 and 2, characterized in that the mold body (10) is provided with a unidirectional laminate (12) distributed over its total profile cross-section over its entire length. Method according to claims 1 and 2, characterized in that the mold body (10) is provided with a unidirectional laminate (12) in its overall length, but only in parts of the profile cross-section. Method according to claims 1 to 4, characterized in that the rear profile area of the mold body (10) is formed as a self-supporting sand structure. Method according to claims 1-5, characterized in that the mold body (10) removed from the mold is provided with a nose reinforcement (25) and an end edge reinforcement (26).