Sewing die and method for strip-shaped composite preform

Abstract

The invention relates to a sewing die and method for a strip-shaped composite preform, and belongs to the field of preparation of composite preforms. The method comprises the following steps that firstly, fiber cloth is cut and laminated; secondly, the relative positions of the fiber cloth of all layers are preliminarily fixed; thirdly, mandrel blocks are connected together and are placed in an inverted U shape; fourthly, the fiber cloth is arranged on a mandrel; fifthly, bottom die blocks are connected together, cover the fiber cloth and are fixed; sixthly, left side die blocks and right sidedie blocks are all connected to the mandrel and a bottom die body so as to complete die closing; seventhly, the mandrel blocks, the bottom die blocks and the side die blocks corresponding to the positions are disassembled and sewn, and after the positions are sewn, the die blocks corresponding to the positions are arranged; and eighthly, the seventh step is repeated until the whole sewing operation is completed. The sewing die and method has the advantages that relatively high dimensional precision and dimensional stability of the preform can be guaranteed, meanwhile, relatively high fiber volume content can be achieved, and a final composite product has excellent mechanical properties.

Description

technical field [0001] The invention relates to the field of manufacturing strip-shaped composite material preforms, in particular to a sewing method for strip-shaped composite material preforms with a U-shaped section. The preform is mainly used for carbon / carbon composite materials, ceramic matrix composite materials or resin matrix composite materials, etc., which require relatively high mechanical properties and dimensional accuracy. Background technique [0002] There is no fiber reinforcement between the layers of traditional two-dimensional laminated composite materials, but the matrix resin plays the role of bonding and transmitting loads, so the performance perpendicular to the layup direction and between layups is relatively weak. When subjected to external loads, laminated composites tend to produce interlaminar failure first, and lower interlaminar strength will lead to poor damage resistance. In order to improve these shortcomings of laminated composites, many ...

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Problems solved by technology

However, this method leads to buckling deformation, bending or even fracture of most of the in-plane fibers, which seriously reduces the mechanical properties of the final composite part, and the dimensional stability of the preform is poor, making it difficult to ensure high dimensional accuracy

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