Composite Preform Needle Punching for Discontinuity Reduction

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Solution Overview

Problem

Current two-dimensional preforming techniques for ceramic matrix composites (CMCs) limit shape complexity and introduce material discontinuities, affecting mechanical performance in gas turbine engines, as they approach the temperature capability limits of Ni-based superalloys.

Innovation Solution

A needle punching process is used to consolidate polymeric preforms containing ceramic or carbon fibers by softening the polymer to insert needles, which manipulate fibers through thickness to reduce discontinuities between sublaminates, allowing for increased complexity and tailored mechanical and thermal properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Shape

If multiple piece preform constructions are used, then shape complexity is improved, but material discontinuities are introduced that reduce mechanical performance

Engineering Contradiction:

Improveshape complexityVSAvoidmechanical performance

Core Design Contradiction:

ShapeVSStrength

Solution Approach 1:

The preform is divided into multiple sublaminates that are joined together, allowing complex shapes to be constructed from manageable segments while maintaining structural integrity through controlled joining regions

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Discontinuities and excess material are removed from the joined regions through needle punching, extracting the harmful elements that would otherwise compromise mechanical performance while preserving the beneficial shape complexity

Inventive Principle:

Principle #2Taking out (Extraction)

2Ease of operation

If needle punching is performed on rigid preforms, then fiber manipulation is limited, but preform structural integrity is maintained

Engineering Contradiction:

Improvefiber manipulationVSAvoidpreform structural integrity

Core Design Contradiction:

Ease of operationVSStability of the object's composition

Solution Approach 1:

The physical state of the preform is temporarily changed by softening the polymer matrix, which allows needles to penetrate and manipulate fibers more easily without compromising the overall structural integrity of the preform

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The polymer is softened before needle punching to facilitate fiber manipulation, and then re-solidified after the punching process to restore structural integrity, effectively preparing the material in advance for the upcoming operation

Inventive Principle:

Principle #10Preliminary action

3Ease of operation

If polymer is softened for needle insertion, then fiber manipulation is enabled, but polymer degradation may occur

Engineering Contradiction:

Improveneedle insertionVSAvoidpolymer integrity

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The polymer undergoes a temporary phase transition from solid to softened state during needle punching, allowing easy needle insertion and fiber manipulation, then returns to its original solid state, completing the phase cycle without permanent degradation

Inventive Principle:

Principle #36Phase transitions

Solution Approach 2:

The softening and solidifying of the polymer occurs in periodic cycles corresponding to the needle punching process, with controlled heating/softening during insertion and cooling/solidifying afterward, preventing cumulative degradation through rhythmic, controlled transitions

Inventive Principle:

Principle #19Periodic action

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This process enhances interlaminar strength, reduces material discontinuities, and enables the fabrication of complex shapes with improved thermal and mechanical properties, suitable for high-temperature gas turbine components, while maintaining desired fiber volume levels.

Implementation Method 1

softening the region between the first sublaminate and the second sublaminate; The softening may be performed by applying heat to the needle, the region, or some combination thereof

Methodology Applied

Scientific EffectHeating: Heating

Implementation Method 2

The softening may performed by applying solvent or water vapor to the polyvinyl alcohol

Methodology Applied

Scientific EffectAbsorption: Absorption (physical)

Implementation Method 3

manipulating the region of discontinuity between the first sublaminate and the second sublaminate to reduce the incoherence between the sublaminates by moving SiC—SiC fibers from the sublaminates through at least part of the region

Methodology Applied

Scientific EffectMechanical Force: Mechanical Force

Data Source

PatentUS10414142B2Needle punching of composites for preform assembly and thermomechanical enhancement

Publication Date: 2019.09.17 ROLLS ROYCE CORP

AI summary

A method of forming a composite preform containing multiple laminates is disclosed. The method may include providing a first sublaminate comprising stacked fibers woven into a fabric; providing a second sublaminate comprising stacked fibers woven into a fabric; joining the first sublaminate and the second sublaminate forming a component comprising a region of discontinuity sandwiched between the first sublaminate and the second sublaminate; rigidizing the component; and softening the region between the first sublaminate and the second sublaminate. In illustrative embodiments, the method may include manipulating the region of discontinuity between the first sublaminate and the second sublaminate to reduce the incoherence between the sublaminates by moving fibers from the sublaminates through at least part of the region between the first sublaminate and the second sublaminate.