Multi-material integrated knit thermal protection for industrial applications

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Solution Overview

Problem

Ceramic fibers are prone to breakage during knitting due to their brittle nature, leading to labor-intensive hand sewing techniques and limitations in forming complex geometries, resulting in products with poor performance and high maintenance costs.

Innovation Solution

A multi-component stranded yarn is developed, comprising a continuous ceramic strand wrapped around a load-relieving process aid strand, which is concurrently knit with a metal alloy wire, allowing for the creation of lightweight, high-temperature capable components with improved mechanical and thermal properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If ceramic fiber sewing thread is twisted in the conventional manner, then the fabric has high tensile strength and high modulus of elasticity, but the ceramic fiber thread is prone to breakage under small radius stress

Engineering Contradiction:
Improvetensile strengthVSAvoidbreakage resistance
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent combines ceramic fibers with a flexible carrier material to form a composite yarn structure. The ceramic fibers provide high tensile strength and heat resistance, while the flexible carrier material prevents breakage during knitting by accommodating small radius stresses. This composite approach allows the fabric to maintain high strength properties while eliminating the brittleness problem of pure ceramic fiber threads.

Inventive Principle:
Principle #40Composite materials

2Ease of manufacture

If hand sewing techniques are employed to fabricate articles from ceramic fiber fabrics, then the fabric can be assembled, but the process is tedious and labor intensive

Engineering Contradiction:
Improvefabrication simplicityVSAvoidmanufacturing efficiency
Core Design Contradiction:
Ease of manufactureVSProductivity

Solution Approach 1:

The patent extracts the flexible carrier material from the final product structure, using it only as a temporary aid during the knitting process. The carrier material enables machine knitting to proceed without ceramic fiber breakage, but is subsequently removed to leave the desired ceramic fiber fabric. This extraction approach allows automated manufacturing while maintaining the integrity of the brittle ceramic fibers throughout the process.

Inventive Principle:
Principle #2Taking out (Extraction)

3Productivity

If conventional knitting techniques are used with ceramic fibers, then production can proceed, but complex geometries cannot be formed due to fiber breakage

Engineering Contradiction:
Improvemanufacturing capabilityVSAvoidgeometry complexity
Core Design Contradiction:
ProductivityVSAdaptability or versatility

Solution Approach 1:

The flexible carrier material acts as an intermediary that protects the ceramic fibers during the knitting process. It allows the knitting machine needles to manipulate the yarn through small radius bends and complex geometries without causing ceramic fiber breakage. The carrier material absorbs the mechanical stress, enabling the formation of complex three-dimensional shapes that would be impossible with conventional ceramic fiber handling.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Ease of manufacture

If ceramic fiber fabrics are produced using current techniques, then the fabric can be manufactured, but the products suffer from part-to-part variance and qualification test failures

Engineering Contradiction:
ImprovemanufacturabilityVSAvoidproduct consistency
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent applies preliminary protection to the ceramic fibers by embedding them in a flexible carrier material before the knitting process begins. This preliminary action prevents fiber breakage during handling and knitting, ensuring that the same number and arrangement of ceramic fibers are incorporated into each fabric piece. This consistency eliminates part-to-part variance and reduces qualification test failures by ensuring uniform product quality across all manufactured items.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP2980289B1Multi-material integrated knit thermal protection for industrial applications
Publication Date: 2020.06.03 THE BOEING CO
  • EP2980289B1 patent drawingFigure 1
  • EP2980289B1 patent drawingFigure 2
  • EP2980289B1 patent drawingFigure 3

AI summary

Knit fabrics (500) having ceramic strands (110), thermal protective members formed therefrom and to their methods of construction are disclosed. Methods for fabricating fabrics for thermal protection using multiple materials which may be concurrently knit are also disclosed. This unique capability to knit high temperature ceramic fibers (110) concurrently with a load-relieving process aid strand (120), such as an inorganic or organic material (e.g. metal alloy or polymer), both small diameter wires within the knit as well as large diameter wires which provide structural support and allow for the creation of near net-shape performs at production level speed. Additionally, ceramic insulation can also be integrated concurrently to provide increased thermal protection.