Elastic Wave Source Location Using Time Difference and Incident Angle
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Solution Overview
Problem
Conventional methods for locating the source of elastic waves in structures face challenges such as limited detection range and dead bands due to the difficulty in accurately determining the propagation velocity of elastic waves in solids, which restricts the measurement range and accuracy.
Innovation Solution
A position location system with a plurality of sensors arranged at a predetermined interval, a time measurement unit, and an angle calculation unit, where the time difference in wave arrival is measured and used to calculate the incident angle, allowing for the location of the wave source without reliance on accurate propagation velocity, and eliminating dead bands by non-parallel sensor arrangements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the propagation velocity of elastic waves is accurately determined to perform source location, then the location precision is improved, but it becomes extremely difficult to achieve due to material anisotropy and internal structure variations
Solution Approach 1:
The invention extracts and removes the dependency on propagation velocity from the source location process. By using time difference of arrival measurements between multiple sensors without requiring knowledge of wave speed, the method eliminates the difficult measurement parameter while maintaining location accuracy
Solution Approach 2:
The invention changes the measurement parameter from velocity-based calculation to time-difference-based calculation. Instead of measuring propagation velocity and using it to determine source position, the system directly uses arrival time differences at multiple sensors, transforming the problem into one that does not require velocity measurement
2Ease of operation
If conventional sound source-based methods are used for location, then the measurement can be performed, but the detection resolution largely changes depending on arrival direction and dead bands occur
Solution Approach 1:
The invention segments the detection function across multiple sensors arranged in specific geometries (e.g., tetrahedral arrangements). By distributing detection capabilities across multiple sensor positions and using time difference measurements, the system achieves uniform detection resolution in all directions without dead bands
Solution Approach 2:
The invention transitions from directional-dependent detection to three-dimensional time-difference-based localization. By utilizing temporal information from multiple spatial positions rather than relying on directional sensitivity of individual sensors, the system achieves omnidirectional detection capability
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 system expands the measurement range to 360° without dead bands, enabling accurate source location of elastic waves across a wide range, independent of propagation velocity, and facilitates wireless operation with relaxed time synchronization requirements.
Implementation Method 1
location of the oscillation source position of elastic waves using a difference in time at which a signal arrives at a plurality of sensors
Implementation Method 2
AE sensor using a piezoelectric element
Data Source
AI summary
According to one embodiment, a position location system includes a plurality of sensors, a time measurement unit, an angle calculation unit, and a position location unit. The plurality of sensors are arranged at a predetermined sensor interval. The time measurement unit measures a difference in time at which elastic waves arrive at the plurality of sensors. The angle calculation unit calculates an incident angle at which the elastic waves are incident on the plurality of sensors on the basis of the time difference. The position locator locates a source of the elastic waves on the basis of the incident angle. The predetermined sensor interval is a distance determined on the basis of a sound velocity of elastic waves propagating in a structure in which the plurality of sensors are arranged and a frequency characteristic of the sensor.