Compact Flexural Wave Direction Sensor Using Mechanical Resonators
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Solution Overview
Problem
Existing systems for sensing the incident angle of plate bending waves require significant spatial distance between sensors, making them unsuitable for compact designs and applications that benefit from smaller sizes.
Innovation Solution
A flexural wave direction sensor with two or three mechanical resonators positioned on a plate, each with an associated oscillation amplitude detector, which generates a ratio of transformed oscillation amplitudes to determine the incident angle, allowing for compact and efficient detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If phase-difference acoustic direction sensing systems are used to measure the difference in arrival time at two or more spaced-apart wave sensors, then the incident angle of acoustic waves can be sensed, but the spatial distance between sensors must be substantial, making the design very difficult to adapt to compact applications
Solution Approach 1:
The patent replaces the conventional acoustic phase-difference measurement system with a mechanical vibration-based sensing system. Mechanical resonators coupled to the plate structure directly sense flexural waves through mechanical coupling, eliminating the need for spaced-apart acoustic sensors. This substitution enables incident angle detection while allowing sensors to be positioned in close proximity on the plate surface.
Solution Approach 2:
The patent transitions from measuring temporal phase differences in the time domain to measuring spatial vibration amplitude ratios across multiple resonators. By analyzing the ratio of vibration amplitudes at different locations and orientations on the plate, the system determines incident angle through spatial distribution patterns rather than temporal phase relationships, enabling compact sensor placement.
2Ease of operation
If multiple spaced-apart wave sensors are used to detect phase difference for incident angle sensing, then direction detection can be achieved, but the system becomes unsuitable for applications requiring small size
Solution Approach 1:
The patent merges multiple sensing functions into a single integrated system. Multiple mechanical resonators are coupled to the plate and work together as a unified sensing array, with each resonator contributing to the overall incident angle determination through its vibration response. This merging enables direction sensing while keeping the total system volume small, as the resonators can be positioned close together on the plate surface.
Solution Approach 2:
The mechanical resonators serve multiple functions: they act as both the sensing elements for detecting flexural wave vibrations and as the structural components for determining incident angle through their spatial arrangement and vibration amplitude ratios. This multi-functionality eliminates the need for separate acoustic sensors and processing systems, reducing overall system size while maintaining direction sensing 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
Enables accurate detection of the incident angle of flexural waves in a compact form, suitable for smaller designs, and effective in localizing vibration sources within structural plates.
Implementation Method 1
first and second mechanical resonators positioned on the plate and configured to oscillate in response to an incident flexural wave
Implementation Method 2
a controller configured to receive and Fourier transform oscillation amplitude data from each oscillation amplitude detector
Data Source
AI summary
Devices for detecting plate bending, or flexural, waves include at least two mechanical resonators positioned on a plate in a specified configuration. Each mechanical resonator has an associated oscillation amplitude detector, such as a laser vibrometer, configured to detect resonant oscillation of the mechanical resonator in response to an incident flexural wave. A ratio of frequency-dependent oscillation data for each mechanical oscillator is compared to a calibration curve to determine the angle of incidence of the flexural wave.