Geometry Compensating Transducer Attachment for Ultrasonic Inspection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Ultrasonic inspection of composite structures with chamfers or countersunk surfaces is hindered by refraction and scattering of ultrasonic beams due to acoustic velocity and impedance mismatches, leading to inaccurate detection of irregularities.
Innovation Solution
A geometry compensating transducer attachment with complementary angled surfaces made of matching composite material, which restores the structure to a plate-like configuration, minimizing refraction and scattering by matching acoustic velocity and impedance, allowing for accurate ultrasonic inspection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If ultrasonic transducers are positioned parallel to the surface at an angle to the plies, then the ultrasonic beam is channeled by fibers, but laminar irregularities do not return echoes and inspection accuracy deteriorates
Solution Approach 1:
A geometry compensating attachment made of CFRP material is introduced as an intermediary between the ultrasonic transducer and the chamfered surface. This attachment has a complementary angle to the chamfer, creating a plate-like configuration that allows ultrasonic beams to travel perpendicular to the plies, enabling laminar irregularities to return detectable echoes while maintaining ease of operation
Solution Approach 2:
The attachment changes the effective inspection angle parameter by providing a complementary angled surface. This parameter change transforms the oblique incidence geometry into a perpendicular incidence geometry relative to the plies, allowing laminar irregularities to reflect echoes back to the transducer
2Adaptability or versatility
If ultrasonic transducers are positioned on a plastic wedge, then the beam refracts at an angle to the plies, but laminar irregularities still do not return echoes and inspection accuracy deteriorates
Solution Approach 1:
The geometry compensating attachment is made of CFRP material that matches the acoustic characteristics (velocity and impedance) of the composite structure being inspected. This homogeneity eliminates refraction and acoustic impedance mismatch, allowing the ultrasonic beam to travel straight through the attachment and into the structure perpendicular to the plies, enabling accurate detection of laminar irregularities
3Area of stationary object
If shaped ultrasonic arrays are used to sweep sound beams through the material, then beam coverage is improved, but echo returns from delaminations remain marginal and inspection accuracy is limited
Solution Approach 1:
The geometry compensating attachment serves as a mediator that creates a plate-like configuration, allowing ultrasonic beams to enter the structure perpendicular to the plies. This intermediary geometry ensures that regardless of beam sweeping or array shaping, the beams always travel in the optimal direction through the material, maximizing echo returns from delaminations and improving detection accuracy
4Adaptability or versatility
If ultrasonic inspection is performed from a parallel back surface, then inspection of angled surfaces is possible, but access to the back side is not always possible and inspection feasibility is reduced
Solution Approach 1:
The geometry compensating attachment is placed on the accessible angled surface and acts as an intermediary that creates a plate-like configuration. This allows ultrasonic inspection to be performed from the accessible side only, eliminating the need for back surface access while maintaining accurate detection of laminar irregularities through the complementary angled geometry
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 solution enables accurate detection of irregularities beneath chamfers and countersunk surfaces by eliminating refraction and scattering, resulting in improved ultrasonic inspection accuracy and simplification of the inspection process.
Implementation Method 1
the ultrasonic beam enters the structure and is channeled by the fibers in the plies... Due to the velocity difference between the plastic wedge and the carbon fiber material, the ultrasonic beam refracts at an angle to the plies
Implementation Method 2
ultrasonic inspection of irregularities beneath angled interfaces such as chamfers and countersunk surfaces may not be accurate since those types of surfaces tend to refract and scatter the ultrasonic beams
Implementation Method 3
transmitting an ultrasonic beam through the geometry-compensating structure into the structure to be inspected
Implementation Method 4
The bond line interface between the wedge or plug attachment and the structure has a negligible effect on the ultrasonic beam since there is no refraction or acoustic impedance loss
Data Source
Figure 1
Figure 2~4
Figure 5
AI summary
A geometry compensating transducer attachment for ultrasonic inspection of a structure includes a geometry-compensating structure having at least one angled surface configured to engage the structure to be inspected, and the geometry-compensating structure having an acoustic velocity generally matching an acoustic velocity of the structure to be inspected (Fig. 1).