Substrate Monolith Vibration Testing for Crack Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Substrate monoliths used in exhaust gas treatment are prone to cracking due to mechanical and thermal shocks during manufacturing, making visual inspection inefficient and time-consuming, and existing auditory methods rely on operator perception, leading to inconsistent results.
Innovation Solution
A method involving applying an impulse to the substrate monolith with an angled impact tool, sensing mechanical vibrations, determining the fundamental frequency, and comparing it to a reference, using frequency domain analysis to discern defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If visual inspection is used to detect cracks in substrate monoliths, then defects may be identified, but the method is time-consuming and can only be applied to a small sample percentage
Solution Approach 1:
The patent replaces visual inspection (optical system) with acoustic vibration analysis. An impact tool excites the substrate monolith to produce mechanical vibrations, and a sensor detects these vibrations. The vibration characteristics (frequency, amplitude, damping) are analyzed to identify cracks, substituting the mechanical/vibration-based detection system for the visual inspection method.
Solution Approach 2:
The patent introduces vibration as an intermediary physical phenomenon to detect cracks. Instead of directly observing cracks visually, the method uses mechanical vibrations induced by an impact tool as a mediator. The vibrations interact with the substrate structure, and crack presence is inferred from changes in vibration characteristics, making defect detection faster and more scalable.
2Measurement precision
If the 'tap' test method is used with human operators, then defect detection is possible, but the method requires operator experience and perception varies from person to person
Solution Approach 1:
The patent replaces the human sensory system (ear and brain processing of sound) with an automated electronic vibration sensing and analysis system. A sensor detects mechanical vibrations, and a processor automatically analyzes vibration characteristics such as frequency spectrum and damping ratios to identify cracks, eliminating variability in human perception and experience levels.
Solution Approach 2:
The patent implements an automated feedback system where vibration data from the substrate is processed through algorithms that compare measured characteristics against reference values or thresholds. The system provides objective pass/fail decisions based on quantified vibration parameters, eliminating subjective interpretation and ensuring consistent, repeatable results across different testing instances.
3Reliability
If substrate monoliths are tested for cracks during manufacture, then defects can be identified before dispatch, but the monoliths are fragile and prone to cracking during mechanical manipulation
Solution Approach 1:
The patent applies a controlled, minimal impulse to the substrate monolith rather than subjecting it to the full mechanical manipulation sequence. The impact tool delivers a brief, localized vibration excitation that is sufficient to generate detectable vibration signals from cracks without imposing the cumulative mechanical loads that would occur during complete handling and installation procedures.
Solution Approach 2:
The patent performs crack detection testing at an optimal point in the manufacturing process—after the substrate has sufficient structural strength from sintering and washcoat application, but before final installation. This timing provides a 'cushioning' effect where the substrate is strong enough to withstand the vibration test without damage, yet defects are still present and detectable.
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 method quickly and reliably detects cracks and defects in substrate monoliths, suitable for production lines, reducing damage risk and eliminating reliance on human perception.
Implementation Method 1
applying an impulse to the substrate monolith with an impact tool to induce mechanical vibrations in the substrate monolith
Implementation Method 2
sensing the mechanical vibrations of the substrate monolith
Data Source
AI summary
A method of testing a substrate monolith (1), the substrate monolith (1) comprising:i) a plurality of channels extending longitudinally along a Z-axis of the substrate monolith (1); andii) an array of walls extending along the Z-axis and forming partitions between adjacent channels;wherein the array of walls comprises first walls (10) orientated parallel to a first-axis of the substrate monolith (1) and second walls (11) orientated parallel to a second-axis of the substrate monolith (1), the first-axis and the second-axis both being orthogonal to the Z-axis;the method comprising the steps of:a) applying an impulse (J) to the substrate monolith (1) with an impact tool (22) to induce mechanical vibrations in the substrate monolith (1);b) sensing the mechanical vibrations of the substrate monolith (1);c) determining a fundamental frequency of the sensed mechanical vibrations; andd) comparing the fundamental frequency of the sensed mechanical vibrations to a fundamental frequency obtained from testing of a second substrate monolith;wherein in step a) an impulse vector (30) of the impulse (J) has a non-zero first-axis component (31) and a non-zero second-axis component (32).