Fan Blade Edge Guard Bonding With Sensor-Based Bondline Mapping
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Solution Overview
Problem
Adhesive bonding in aerospace and other fields faces challenges in achieving precise bondline thickness and surface fit between complex, three-dimensional components, leading to inefficient and laborious fit checking processes, especially when bonding fibre-reinforced composites with metal components.
Innovation Solution
A method using a flexible, compressible pressure sensor layer between components to measure bondline thickness variations, generating a bondline thickness profile for precise adhesive application, with an array of piezoelectric sensors and a control processor determining the adhesive application schedule to ensure accurate adhesive distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional film adhesive testing is used to check bondline thickness, then the process can identify contact and non-contact regions, but the measurement precision is insufficient and the process becomes extremely laborious and time-consuming
Solution Approach 1:
The patent replaces the mechanical film-based gap testing system with a capacitive sensing system that uses electrical fields to measure bondline thickness. The capacitive gap thickness sensors detect changes in capacitance corresponding to gap thickness variations, providing precise measurements without the laborious manual procedures required by film-based methods.
Solution Approach 2:
The patent accelerates the fit-checking process by using automated capacitive measurements that can rapidly scan multiple areas of the bonding interface simultaneously. This allows the bondline thickness profile to be determined in a single operation rather than through multiple iterative film application and inspection cycles.
2Manufacturing precision
If multiple layers of adhesive are applied iteratively to achieve proper bondline thickness, then adhesive fill accuracy can be improved, but the device complexity and process labor increase significantly
Solution Approach 1:
The patent performs preliminary measurement of the bondline thickness profile using capacitive sensors before adhesive application. This allows the adhesive application schedule to be determined in advance with precise knowledge of the actual gap thickness at each location, eliminating the need for iterative adhesive layering and repeated fit checking.
Solution Approach 2:
The patent uses the measured bondline thickness profile as feedback to determine the optimal adhesive application schedule. The system analyzes the measured gaps and calculates the precise amount and location of adhesive needed, providing a controlled feedback loop that ensures accurate adhesive fill without trial and error.
3Loss of information
If conventional film testing is used to detect bondline thickness variations, then some regions can be identified for additional adhesive, but the quantity and area of additional adhesive cannot be determined precisely
Solution Approach 1:
The capacitive sensor array serves multiple functions: it measures gap thickness, identifies regions requiring adhesive, determines the precise quantity of adhesive needed, and maps the complete bondline thickness profile. This single measurement system provides all the information required for precise adhesive application planning.
Solution Approach 2:
The patent transforms the physical gap thickness parameter into an electrical capacitance parameter that can be measured precisely by the capacitive sensors. This parameter transformation allows for quantitative measurement and analysis of bondline thickness variations, enabling precise calculation of the adhesive application schedule.
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 method significantly reduces the labor and time required for fit checking, achieving precise adhesive fill accuracy and improving bondline thickness consistency, even in complex geometries, by directly measuring pressure variations and converting them into an adhesive application schedule.
Implementation Method 1
an array of capacitive gap thickness sensors between the doubler and the structure surface; measuring the gap thickness between the doubler and the structure surface in a plurality of areas
Data Source
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AI summary
Methods and apparatus are described for improving fit checking at the bonding interface of a first component, such as a fan blade (1), and a second component, such as an edge guard (2) for the fan blade (1), to be bonded by adhesive. A bondline thickness profile over the area of the bonding interface is determined by interposing a compressible, flexible sensor layer between the components before they are bonded. The sensor layer contains an array of piezoelectric elements which indicate local bondline thickness by signalling pressure due to compression of the layer. The bondline thickness profile can be processed by a programmed control processor to produce an adhesive application schedule prescribing the shapes of pieces of adhesive film which, when applied over the bonding interface, will build up an adhesive layer corresponding in thickness to the bondline thickness. The sensor layer can be prepared as a kit of shaped panels or as a contoured preform (55) matching the form of the bonding interface.