Fiber Optic Sensor Embedded in Structural Joint

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Conventional structural health monitoring methods for aircraft airframes require temporary removal from service and are susceptible to sensor damage, making it difficult to integrate effective monitoring systems into composite structures without disrupting active service.

Innovation Solution

Embedding fiber optic sensors within the joints of composite airframes, specifically within preforms that form adhesive interfaces between structural components, allows for in-situ monitoring of structural health without disrupting service, using fiber optic cables that intersect to form a grid-like pattern and communicate with a controller for health assessment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional inspection methods (visual inspection, eddy current scanning, ultrasonic transmission, acoustic emission, X-ray inspection) are used to monitor structural integrity, then structural health can be identified, but the aircraft must be temporarily removed from service

Engineering Contradiction:

Improvestructural health monitoring capabilityVSAvoidaircraft operational availability

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent merges the structural joint itself with the monitoring function by embedding fiber optic sensors within the adhesive joint between structural components. This integration allows the joint to simultaneously perform its mechanical connection function and structural health monitoring function, eliminating the need for separate inspection operations that would require removing the aircraft from service.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The structural joint performs self-monitoring through embedded sensors that continuously detect structural health parameters. The system enables the structure to monitor itself in real-time during operation, eliminating the need for external inspection systems and scheduled maintenance removals from service.

Inventive Principle:

Principle #25Self-service

2Reliability

If externally mounted sensor systems are used for structural health monitoring, then monitoring can be implemented, but the sensors are susceptible to damage and integration is difficult on existing structures

Engineering Contradiction:

Improvestructural health monitoring capabilityVSAvoidsensor damage susceptibility

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The fiber optic sensors are nested within the adhesive joint material itself, placing the sensing elements inside the protective envelope of the structural joint. This nested configuration protects the sensitive optical fibers from external damage while maintaining their ability to detect structural health changes in the bonded joint.

Inventive Principle:

Principle #7Nested doll (Nesting)

Solution Approach 2:

The sensors are merged with the joint structure during manufacturing, making the monitoring system an intrinsic part of the joint rather than an external attachment. This integration eliminates the vulnerability of externally mounted sensors to damage during operation and simplifies implementation on both new and existing structures.

Inventive Principle:

Principle #5Merging (Combining)

3Productivity

If fiber optic sensors are embedded within joints, then continuous monitoring without service removal is enabled, but sensor integration complexity increases

Engineering Contradiction:

Improveaircraft operational availabilityVSAvoidsensor integration complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The fiber optic sensors are embedded within the adhesive joint during the joint manufacturing process, before the structure enters service. This preliminary integration action incorporates the sensors into the joint structure itself, eliminating the need for complex post-manufacturing installation and reducing overall system complexity.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The adhesive joint serves multiple functions: it provides mechanical bonding between structural components and simultaneously houses the fiber optic sensors for health monitoring. This multi-functionality reduces the need for separate monitoring hardware and simplifies the overall system architecture.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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

Enables continuous, damage-resistant structural health monitoring of aircraft airframes, allowing for timely maintenance and preventing catastrophic failures while maintaining operational readiness.

Implementation Method 1

the sensor includes at least one fiber optic cable

Methodology Applied

Scientific EffectOptical fiber sensing: Optical Fibre

Data Source

PatentUS10605631B2Structural pi joint with integrated fiber optic sensing

Publication Date: 2020.03.31 SIKORSKY AIRCRAFT CORP

AI summary

A structural health monitoring system includes a first component and a second component associated at a joint. At least one sensor is embedded within the joint to monitor a health of at least one of the first component, the second component, and the joint.