Passive Reversible Deformation Sensor for Structural Monitoring
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Solution Overview
Problem
Existing sensors for detecting and counting vehicle passages or stress cycles on structures, such as bridges, face limitations including short lifespan, pyrotechnic safety concerns, sensitivity to electromagnetic fields, and large size, making them prone to vandalism and ineffective for multiple detection thresholds in small structures.
Innovation Solution
A passive and reversible microsensor with a support having first and second parts that can be fixed to a structure, equipped with toothed wheels and drive beams to detect and count deformation cycles, allowing for multiple detection thresholds without an energy source, and designed to be compact and insensitive to electromagnetic fields.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If active sensors with power supply and microprocessor are used for detecting and counting temperature cycles, then measurement precision and counting accuracy are improved, but device complexity and sensitivity to electromagnetic fields increase
Solution Approach 1:
The patent extracts and removes all active electronic components (power supply, microprocessor, electronic circuits) from the sensor system, retaining only the essential mechanical detection elements (bimetallic strip, gear wheel, counter mechanism) that can function passively through mechanical energy from temperature-induced deformations
Solution Approach 2:
The patent replaces electronic detection and counting systems with a purely mechanical system where the bimetallic strip's thermal deformation directly drives a gear wheel that mechanically increments a counter, eliminating sensitivity to electromagnetic fields while maintaining counting functionality
2Measurement precision
If sensors with power supply and electronic processing means are deployed, then detection and counting capabilities are improved, but lifespan is limited by power supply duration
Solution Approach 1:
The sensor system is designed to be self-powered, where the temperature variations being measured directly drive the bimetallic strip which in turn powers the mechanical gear wheel and counter mechanism through pure mechanical energy transfer, eliminating the need for external power supplies and batteries
Solution Approach 2:
The patent completely removes power supply components (batteries, electrical connections) from the sensor system, relying solely on the mechanical energy generated by temperature-induced deformations of the monitored structure to operate the detection and counting mechanisms
3Measurement precision
If electronic sensors and processing means are used for vehicle passage counting, then measurement precision is improved, but pyrotechnic safety is compromised due to risk of spark formation
Solution Approach 1:
The patent replaces all electronic sensing and signal processing components with mechanical equivalents: electronic detection is substituted by mechanical deformation of the bimetallic strip, and electronic signal processing is replaced by mechanical gear wheel rotation and counter incrementation, eliminating sources of sparks and electromagnetic interference
4Measurement precision
If large-sized sensors with processing means are installed on structures, then detection capability is improved, but vulnerability to vandalism increases due to visibility
Solution Approach 1:
The patent removes all bulky electronic processing means, power supplies, and associated infrastructure from the sensor system, retaining only the essential mechanical components (bimetallic strip, gear wheel, counter) that can be miniaturized and integrated into a compact, discreet unit suitable for small bridge structures
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 microsensor provides long-lasting, safe, and accurate counting of deformation cycles across multiple thresholds, reducing visibility and vulnerability to vandalism, while being immune to electromagnetic interference and energy source limitations.
Implementation Method 1
comprising a bimetallic strip whose free end is capable of displacing under the action of temperature variations
Implementation Method 2
an elastic element the ends of which are connected respectively to said first and second longitudinal parts
Data Source
Figure 1a
Figure 1b
Figure 2~4b
AI summary
The present invention relates to the field of microsensors, and specifically to a passive, reversible deformation sensor, particularly a sensor for detecting deformation cycles in a direction OX of a structure, specifically during cycles of temperature or mechanical stresses to which said structure is subjected, said sensor comprising a means (4, 5, 6) for detecting and, preferably, counting cycles of variations in the distance between two points or areas of a structure, said means comprising a substrate having first and second portions (41, 44) capable of being attached to said two points or areas of the structure, respectively, the detection means being combined with each of said first and second portions of the substrate, characterized in that the detection means comprises means (541, 542, 543, 551, 552, 553, 561, 562, 563) for distinguishing between at least two different thresholds of cycles of variations in distance.