Ultrasonic Inspection of Diffusion Bonded Articles
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Ultrasonic inspection methods for anisotropic materials like titanium alloys face challenges in accurately detecting defects due to the diffusion bond interface acting as a weak reflector, leading to spurious indications of bond defects, especially in single-sided inspections, and existing two-sided methods can be inaccurate and result in false positives/negatives.
Innovation Solution
A method that normalizes ultrasonic waveforms to a nominal axis using a mathematical model derived from surface geometry measurements, allowing for accurate identification of signature signals from one side of the article, and compares these signals to characterize the bond interface, even after bonding, to assess bond quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If single-sided ultrasonic inspection is used, then inspection accessibility is improved, but measurement precision deteriorates due to spurious defect indications from anisotropic materials
Solution Approach 1:
The patent changes the inspection parameter from single-sided to double-sided ultrasonic inspection. This allows access to both surfaces of the article, enabling the transmission of ultrasonic waves through the diffusion bond interface from both sides. The dual-sided approach provides complementary information that resolves the spurious indications caused by anisotropic crystal structures, thereby improving measurement precision while maintaining inspection accessibility.
Solution Approach 2:
The patent adds a spatial dimension to the inspection by performing ultrasonic testing from both sides of the article rather than just one side. This dimensional expansion allows the inspection system to capture waveforms from opposite directions, providing a more complete characterization of the diffusion bond interface and eliminating false defect indications that cannot be resolved from a single viewpoint.
2Measurement precision
If two-sided ultrasonic inspection with spectral analysis is used, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent replaces complex mechanical or manual analysis methods with spectral (Fourier) analysis performed by a computer system. Instead of requiring complex physical setups or manual waveform interpretation, the invention uses digital signal processing to automatically extract phase information from ultrasonic waveforms. This substitution of computational methods for mechanical complexity reduces overall system complexity while maintaining high measurement precision.
Solution Approach 2:
The patent uses phase comparison of ultrasonic waveforms as a simplified copy or representation of the physical bond quality. Rather than directly measuring complex physical properties of the diffusion bond, the invention captures phase characteristics of transmitted waves from both sides, which serve as informative copies that reveal bond quality without requiring direct complex measurement of the interface itself.
3Ease of operation
If conventional gating method is used to identify diffusion bond signal, then ease of operation is improved, but measurement precision deteriorates due to inaccurate signal identification
Solution Approach 1:
The patent implements a feedback mechanism where the identified diffusion bond signal location from spectral analysis is used to refine the gating parameters for subsequent inspections. The system continuously adjusts the time window (gate) based on the precise signal location determined through phase analysis, creating a closed-loop system that improves both accuracy and ease of operation with each measurement cycle.
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 approach provides a more accurate and reliable detection of bond defects with reduced errors, allowing for inspection from one side and improving the identification of bond quality by minimizing noise and enhancing signal clarity, potentially reducing errors by a factor of three compared to previous methods.
Implementation Method 1
an ultrasonic wave is produced by a transducer and transmitted through a medium to the article to be inspected. In a single sided inspection, the transducer transmits an ultrasonic wave, which is then reflected back to the transducer by deformities or discontinuities in the structure of the article
Implementation Method 2
phase differences of 180° are taken to be 'natural' differences that occur due to the acoustic impedance mismatch of the grain colonies either side of the bond
Implementation Method 3
in anisotropic materials, the speed of sound in the material is dependent on the direction of travel of the sound wave relative to the crystallographic orientation of the material
Implementation Method 4
The bond interface 12 will act as a weak planar reflector due to the different crystallographic orientations above and below the bond interface 12
Implementation Method 5
using the transducer arrangement to transmit a first ultrasonic wave from a first side of the first article through the first surface of the first article at a plurality of inspection locations along the nominal axis, and receiving a first transmitted waveform which has passed through the first surface
Data Source
Figure 1~2
Figure 3a~4b
Figure 5a~5b
AI summary
An ultrasonic inspection method for inspecting a first article. The method comprises, in a first inspection process: measuring the distance between a first surface of the first article and a nominal axis at three or more measurement locations along the axis of the surface; using the measured distances to produce a mathematical model of the surface of the first article; transmitting an ultrasonic wave from a first side of the first article through the first surface of the first article at a plurality of inspection locations along the axis of the first surface, and receiving a transmitted waveform which has passed through at least part of the first article; using the model to normalise each transmitted waveform at each inspection location to the nominal axis; and identifying a signature signal from the normalised transmitted waveform at each inspection location.