JPS6246633A - Manufacture of rotor tube - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention is directed to a 71- A method of manufacturing a rotor shed (made from fibers embedded in a rigid material) is used.

[Prior art]

Traditionally, rotor tubes made from fiber-reinforced composite materials are typically wound around a mandrel as an endless transition or mat of fibers, consisting of layers of fibers with different orientations. During operation of the rotor, the rotor is loaded in particular under tensile stress in its circumferential direction. This load exerts different effects on the individual fiber IIi layers, corresponding to the fiber orientation.

The tensile strength in the fiber direction is determined by It has been confirmed that there is. A crack is thereby formed in the fiber region, which propagates laterally.

Remedies have been taken to address this by pre-tensioning the fibers and curing them with a matrix material, thereby creating a residual compressive stress in the resin which constitutes a kind of pre-stretching capacity. This increases the permissible stretching area in the transverse direction of the fibers.

This method is well known and has been applied to glass fiber composites. (Zeits)
chrift) r plastics J”Kun
ststone” Volume 74, 1984, No. 9, 520
(page 526) A malleable matrix material is used here, since it withstands the stretching of the glass fibers during operation due to its high stretching. This solution is generally only suitable for applications where there are no temperature loads.

The object of the present invention is to improve the method for producing high temperature resistant fiber composites.

According to the invention, this problem is solved by the features recited in claim 1. The method includes the manufacture of tubes made from fibers embedded in a matrix material, in which the fibers are wound onto a radially expanding mandrel and JI
This method of manufacturing a rotor tube consists of curing M with a matrix material while maintaining it in a stretched state, and is characterized by using fibers with high strength and high elastic modulus as the fibers.

The invention is based on the finding that the requirements regarding the stretching of the matrix U l"11 can be modified by the selection of fibers due to their elasticity variations. If the fibers have a higher modulus, the stretching is smaller and they can be further shaped. Harder, stiffer matrix materials can be used; such materials have higher thermal stability since elongation is inversely proportional to temperature stability.

The solution of the invention increases the strength of effective fiber composites.
A method is provided that can be used and is independent of the operating temperature at which the composite is exposed.

The method according to the invention has the advantage that during the production of fiber composites, relatively high residual compressive stresses can be introduced into the rematrix material with only a small elongation due to the high modulus of the fibers.

Carbon fiber intermediate grade ([M) or 4, 1 high tensile strength type (ST)
It has been found that a matrix material having an elongation of 5% or less (pure resin molding material) can be used. Materials with this level of strength have thermal stability up to at least 100°C. More particularly, high modulus (HM) type fibers are suitable as they have higher strength or elongation than the aforementioned fibers.

Next, embodiments of the present invention will be described in detail with reference to the drawings.

Figure 1 is an enlarged view of the rotor tube and a cross-sectional view showing other parts in more detail with a partial cross-section, and Figure 2 is an enlarged view of one fiber showing the angles at which the fibers are arranged relative to each other. FIG. 3 is a diagram showing the relationship between the tensile stress σ and the elongation ε of the fiber.

The manufacture of rotor tubes or pressure tubes is produced, for example, by either endless fiber wrapping or by application of a 11M mat onto a mandrel 10 in which the fiber layers 11 to 14 are radially expandable. The mandrel 10 is expanded, for example by hydraulic pressure or mechanical action, and held at the curing temperature of the matrix until the 71-rix material is cured.

In this way, the fibers which are spread out in the direction of the load, especially those in the circumferential direction of the layer 14, are elastically biased.

When the radial force 15 is relaxed and the composite tube 16 cools, the stretched fibers will tend to return to their initial state.

This shrinkage, however, is prevented by the hardened matrix material 17. This residual compressive stress is caused by the generation of stress in the matrix material 17 when the tube 16 expands, while the relaxation of the compressive stress occurs first when the degree of tension is low, and when the stress becomes very large 71 - has the effect of creating tensile stresses within the lix material.

The tensile stress σ acting on the fibers 18 and 19 and the fibers 18 and 19 is resisted by the fibers themselves in the case of the fiber layer 14 parallel to the tensile stress where the tensile strength is maximum, as shown in FIG. will be done. Lengthwise fiber 20
is different in the layer 11 since in that case the tensile stress σ acts transversely to the fiber direction. The contribution to resisting longitudinal stress in this layer is the matrix material 17
given by. The so-called transverse tensile strength is the lowest.

However, if @silviculture 1G is composed of fibers with a low modulus of elasticity, as in the case of glass fibers used in known methods, then σ8
The tensile stress of will cause an elongation in the relatively thick curve 4 as shown in Figure 3, curve 2.This elongation is 71-
The elongation of the lix material can be exceeded sufficiently to cause cracks 22 between the fibers despite the preliminary elongation.

However, if fibers 18 to 20 are used with high modulus and tensile strength, as in the example of curve [l] in Figure 3, then the same tensile stress σ8 will be applied to the composite structure. This will result in a small elongation or stretch ε1. In this case, a particularly satisfactory fiber is a medium-grade charcoal M fiber with a modulus of elasticity of 295 GPa and a tensile strength of up to 510 ON/G. Furthermore, high tension (HS)
T) or high modulus (HM) type carbon fibers can also be used.

(Brass Dicks Technology)
hnik) VD1 Publishing House, pages 167-169) In conjunction with these fibers, 7-tricks binders based on diglycidyl ether-bis71-nol as resin and diaminodiphenylsulfone as curing agent can be used. Such a 71 helix material is 100°CJ:
″c has thermal stability.

A further suitable matrix material with a stretch of less than 5% is a resin of diglycidyl needle-bisphenol A plus methylde-1-rapidorophthalic anhydride or N-medylimidasol with diluent if necessary. This is the added resin.

In the context of fibers, for example, at a volume of 1i'i 60%, the effective elongation is about 10% of the elongation of 71-Rix@Kun alone, ie the effective elongation of the material is reduced by about 0.5%. such >, r of the pre-stretching in the case of material
The property is of the right meaning, and if the material has a sufficiently high modulus of elasticity, it will serve a useful purpose. Charcoal Ifi fibers provide an excellent combination for heavy-duty, high-strength structures where exceptional thermal stability is required.

[Brief explanation of drawings]

Fig. 1 is a partial cross-sectional view of each fiber layer to explain the structure of the rotor composite tube, and Fig. 2 shows the angles of the fibers arranged relative to each other. Enlarged view of l1Ilt layer, 3rd
Figure t is a diagram showing the relationship between tensile stress σ and elongation ε of the fiber. 10... Mandrel, 11.12, 13.14... Circumferential fiber layer, 15... Radial pressure, 1G... Composite pipe , 17... (σ! conversion 7 trix material, 18.1
9.20...Fibers in the length direction, 22...
- Cracks between fibers, σ...Tensile stress, ε...Elongation.

Claims (6)

[Claims] (1) A method of manufacturing a tube made from fibers embedded in a matrix material, in which the fibers are wound onto a radially expanding mandrel and stiffened by the matrix material while holding the fibers in an elongated state. A method for manufacturing a rotor tube, characterized in that the fibers (18, 19, 20) are fibers with high strength and high elastic modulus. (2) A manufacturing method according to claim 1, characterized in that a humidity-stable matrix material (17) is used as the matrix material. (3) A manufacturing method according to any one of claims 1 and 2, characterized in that carbon fiber is used as the fiber. (4) The carbon fiber has intermediate grade (IM) or high tensile strength (
A manufacturing method according to claim 1, characterized in that carbon fibers of the HST type are used. (5) Bonding the carbon fibers with an epoxy resin system consisting of diglycidyl ether of bisphenol A as the matrix material, diaminodiphenylsulfone or methyltetrahydrophthalic anhydride as the curing agent, and N-methylimidazole as the diluent if necessary. A manufacturing method according to claim 4, characterized in that it is used for. (6) Claims 1 to 5 characterized in that the fibers are high modulus (HM) fibers.
Manufacturing method as described in section.