Phased Array Inspection Fixture for Pi-Bonded Composite Structures
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Solution Overview
Problem
Pi-bonded composite structures in aircraft are difficult to inspect for critical flaws due to their large and complex geometry, making conventional ultrasonic and phased array inspections challenging, especially near joints, corners, and stiffeners.
Innovation Solution
A portable hand-held phased array scanning fixture with an ultrasonic lens and tapered mirror is used to focus and reflect ultrasonic beams into hard-to-reach areas, providing improved scanning coverage and resolution across various angles and geometries.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional ultrasonic and phased array inspection methods are used, then inspection simplicity is maintained, but inspection coverage and detection capability are insufficient for complex geometries
Solution Approach 1:
A water column acts as an intermediary medium between the ultrasonic transducer and the pi-bonded structure, enabling effective ultrasonic transmission and reception. The water column facilitates acoustic coupling and signal transmission into complex geometric areas that would be inaccessible with direct contact methods
Solution Approach 2:
The inspection system transitions from conventional single-dimensional scanning to multi-dimensional inspection capability by using the water column to access areas behind joints, corners, and stiffeners. This enables inspection in previously inaccessible geometric dimensions and orientations
2Ease of operation
If hand-held fixtures are used for phased array inspection, then portability is achieved, but complete inspection coverage near joints, corners, and stiffeners is not possible
Solution Approach 1:
The hand-held fixture is designed with universal applicability to inspect various complex geometric features including joints, corners, and stiffeners. The combination of water column, transducer array, and positioning mechanisms enables a single device to handle multiple inspection scenarios that previously required different specialized equipment
3Strength
If conventional fastening methods are used, then manufacturing simplicity is maintained, but structural strength is reduced
Solution Approach 1:
The water column serves as an intermediary that enables ultrasonic inspection through the pi-bonded structure without compromising the bond integrity. This allows detection of flaws in the high-strength pi-bonded joints while maintaining the structural advantages of the bonding method
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
The fixture enables comprehensive and efficient inspection of pi-bonds, including acute and obtuse angled joints, and stiffeners, enhancing flaw detection capabilities and handling complex geometries.
Implementation Method 1
an ultrasonic transducer and a mirror for reflecting and focussing ultrasonic waves
Implementation Method 2
A portable hand-held phased array scanning fixture with an ultrasonic lens and tapered mirror is used to focus and reflect ultrasonic beams
Implementation Method 3
a mirror for reflecting and focussing ultrasonic waves
Data Source
Figure 1
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Figure 4
AI summary
An inspection fixture is provided that includes a fixture, a lens, an ultrasonic phase array, a mirror and a liquid supply connector. The fixture body includes an inner chamber and an opening to the inner chamber. The lens defines a portion of the inner chamber. The ultrasonic phase array generates ultrasonic signals and is positioned to send the ultrasonic signals through the lens. The mirror is received within the inner chamber and is positioned at 45° in relation to the lens to reflect the ultrasonic signals from the lens, out the opening, to an inspection area of a body to be inspected and to reflect returned ultrasonic signals from the inspection area to the lens. The liquid supply connector is in fluid communication with the inner chamber.