Alternating Braided Fiber Preform Permeability Control

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Solution Overview

Problem

The production of multilayered fiber composite preforms often results in regions with dissimilar permeability due to differences in braiding density, leading to variations in component wall thickness, geometric, and mechanical properties, which can affect the final product's quality and appearance.

Innovation Solution

A method involving the generation of fiber composite preforms with alternating braiding directions for each layer, where the first braided fabric layer is created in one direction and the second in a counter direction, ensuring consistent permeability across the support core, thereby minimizing cutting waste and maintaining uniform braiding density.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a support core is used as the basis for braiding fiber rovings, then automated production efficiency is improved, but regions with dissimilar braiding density and permeability are created

Engineering Contradiction:

Improveautomated production efficiencyVSAvoiduniformity of braiding density

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The invention applies preliminary action by creating a first braided fabric layer with a specific braiding density profile before producing the second layer. The run-up region is deliberately positioned in the first layer, and the second layer is designed to compensate for the permeability variations introduced by this preliminary structure, ensuring uniform overall permeability.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The invention applies local quality by allowing different regions of the braided fabric to have different braiding densities tailored to their specific functions. The run-up region has lower density to facilitate braiding initiation, while the main body maintains high density for structural integrity. The alternating braiding directions create local variations that compensate for permeability differences.

Inventive Principle:

Principle #3Local quality

2Loss of substance

If the braided fabric is started with a minor projection to minimize cutting waste, then material loss is reduced, but the braided fabric does not achieve the predefined nominal braiding density

Engineering Contradiction:

Improvecutting wasteVSAvoidpredefined nominal braiding density

Core Design Contradiction:

Loss of substanceVSManufacturing precision

Solution Approach 1:

The run-up region with reduced braiding density is deliberately created as a preliminary structure in the first braided fabric layer. This preliminary action accepts the density compromise in exchange for minimizing cutting waste, and the defect is subsequently compensated by the second layer's alternating braiding pattern.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The invention converts the harmful effect of reduced braiding density in the run-up region into a beneficial compensation mechanism. The alternating braiding direction in the second layer creates regions of higher effective density that offset the lower density areas, transforming the initial defect into a self-correcting system.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Adaptability or versatility

If dissimilar braiding densities are present in different regions, then permeability variations occur, but this affects component wall thickness uniformity and geometric properties

Engineering Contradiction:

Improvepermeability differentiationVSAvoidcomponent wall thickness uniformity

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The invention applies local quality by allowing different regions to have different braiding densities and permeability characteristics tailored to their specific needs. The run-up region maintains lower density for braiding accessibility, while the main body achieves high density for structural performance, with alternating layers compensating for local variations.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The invention uses composite materials by combining multiple braided fabric layers with alternating braiding directions. This composite structure integrates layers with different permeability and density characteristics, creating a unified preform with uniformly compensated overall properties that maintain component wall thickness uniformity.

Inventive Principle:

Principle #40Composite materials

Data Source

PatentUS11203825B2Method for producing a multilayer fiber composite preform for a fiber composite component

Publication Date: 2021.12.21 BAYERISCHE MOTOREN WERKE AG

AI summary

A method produces a fiber composite preform for a fiber composite component. The fiber composite preform has a plurality of layers of a fiber roving. The method includes: providing a support core for arranging the fiber roving s on a braiding device, the support core having a support core longitudinal axis, producing a first braided fabric layer from fiber rovings on the support core in a first braiding direction parallel to the support core longitudinal axis of the support core by the braiding device, and producing a second braided fabric layer from fiber rovings on the first braided fabric layer by the braiding device. The second braided fabric layer is produced in a second braiding direction parallel to the support core longitudinal axis, the second braiding direction being opposite the first braiding direction.