Split-Resistant Composite Laminate With Modified Fiber Orientation

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Solution Overview

Problem

Traditional composite laminates are prone to uncontrolled splitting along the orientation of fibers when subjected to impact, which can lead to catastrophic failures in applications like aircraft wings due to the propagation of large notch damage.

Innovation Solution

A composite laminate design with reinforcing fibers oriented in specific ranges (3 to 8 degrees, -3 to -8 degrees, 10 to 40 degrees, and 90 degrees) embedded in a matrix, which enhances resistance to longitudinal splitting and increases longitudinal strength while maintaining structural integrity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional fiber orientation (0 degrees, ±45 degrees, 90 degrees) is used, then manufacturing is simple, but the composite exhibits uncontrolled splitting along fiber orientation upon impact

Engineering Contradiction:
Improveresistance to longitudinal splittingVSAvoidfiber orientation configuration
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent changes the fiber orientation parameters from traditional values (0°, ±45°, 90°) to specific non-traditional angles (3-8°, -3 to -8°, 10-40°, -10 to -40°, and approximately 90°). This parameter modification prevents uncontrolled splitting by redirecting crack propagation paths while maintaining structural integrity and load-bearing capacity.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite laminate structure with multiple fiber orientations embedded in a matrix material. This composite configuration combines fibers at different angles to achieve both split resistance and structural strength, utilizing the synergistic effect of multi-directional reinforcement.

Inventive Principle:
Principle #40Composite materials

2Reliability

If fiber orientation is modified to prevent splitting, then reliability improves, but manufacturing precision requirements increase

Engineering Contradiction:
Improvestructural integrity under impactVSAvoidfiber orientation accuracy
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent specifies fiber orientation ranges (3-8°, -3 to -8°, 10-40°, -10 to -40°) rather than exact single values. This range-based specification provides manufacturing tolerance, allowing fibers to be oriented within acceptable bounds without requiring extreme precision, thus balancing reliability improvement with manufacturability.

Inventive Principle:
Principle #35Parameter changes

3Strength

If multiple fiber orientations are used to prevent splitting, then strength increases, but device complexity increases

Engineering Contradiction:
Improvelongitudinal strengthVSAvoidnumber of fiber orientations
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The patent employs a composite laminate with five distinct fiber orientation groups embedded in a matrix. This multi-orientation composite structure achieves enhanced longitudinal strength and split resistance by distributing loads across different fiber directions while arresting crack propagation through the varied orientation patterns.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent applies different fiber orientations at different locations and layers within the laminate. Each orientation group (3-8°, -3 to -8°, 10-40°, -10 to -40°, 90°) serves a specific function in resisting splitting or bearing loads in particular directions, optimizing local structural performance.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP2925518B1Split resistant composite laminate
Publication Date: 2018.11.14 THE BOEING CO
  • EP2925518B1 patent drawingFigure 1
  • EP2925518B1 patent drawingFigure 2
  • EP2925518B1 patent drawingFigure 3

AI summary

A composite laminate, method of forming same, and use for same are disclosed. One example of a composite laminate has multiple layers or plies (305A-305E) composed of generally parallel reinforcing fibers (315A-315E) embedded in a matrix (305M). The reinforcing fibers have orientations in the ranges of 3 to 8 degrees, -3 to -8 degrees, 10 to 40 degrees, -10 to -40 degrees, and approximately 90 degrees, the orientations being with respect to a predetermined axis (320), such as an axis of tension (T). A method of manufacturing a composite laminate includes laying a resin and fibers having these orientations and then curing the resulting laminate. One example of a use is for the skin on the fuselage or wing of an aircraft.