Strain Sensor Discriminating Tensile and Compressive Stresses
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Solution Overview
Problem
Existing passive microsensors in the field of road infrastructure cannot discriminate between tensile and compressive stresses, and they lack the ability to detect multiple deformation thresholds, limiting their effectiveness in monitoring structural evolution under varying loads.
Innovation Solution
A passive sensor system that includes a deformation measuring assembly and an actuation device with an intermediate assembly and thrust part, allowing measurement discrimination between tensile and compressive stresses by actuating the deformation measuring assembly only during specific directional movements of the sensor parts, thereby enabling the detection of distinct deformation thresholds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a passive sensor uses a simple counting mechanism to detect stress cycles, then it can count the number of cycles, but it cannot discriminate between tensile and compressive stresses
Solution Approach 1:
The sensor is divided into two independent detection systems: a first detection system with a first beam and first counting wheel for detecting stress cycles in one direction, and a second detection system with a second beam and second counting wheel for detecting stress cycles in the opposite direction. This segmentation allows the sensor to discriminate between tensile and compressive stresses while maintaining a relatively simple overall structure.
Solution Approach 2:
Each detection system is optimized for a specific stress direction: the first beam and first counting wheel are configured to respond only to stresses in one direction, while the second beam and second counting wheel are configured for the opposite direction. This local specialization enables precise discrimination of stress types without requiring complex global mechanisms.
2Measurement precision
If a single sensor is used to monitor structural evolution, then it simplifies installation, but it cannot detect multiple deformation thresholds simultaneously
Solution Approach 1:
The sensor integrates multiple detection functions within a single device: it can detect stress cycles, discriminate between tensile and compressive stresses, and identify multiple deformation thresholds simultaneously. The first and second detection systems work together to provide comprehensive monitoring capabilities, making the sensor versatile while maintaining simple installation as a single unit.
3Measurement precision
If multiple sensors are deployed to detect different stress directions and thresholds, then measurement capabilities are enhanced, but installation complexity and cost increase
Solution Approach 1:
The patent merges the functionality of multiple separate sensors into a single integrated sensor system. The first and second detection systems, which would traditionally require separate sensors, are combined into one device with a common support structure. This consolidation maintains comprehensive stress and deformation monitoring capabilities while simplifying installation and reducing the overall number of components.
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 sensor effectively discriminates between tensile and compressive stresses and detects multiple deformation thresholds, providing accurate monitoring of structural evolution under different load conditions without requiring multiple sensors, which is particularly advantageous for small or sensitive structures.
Implementation Method 1
an elastic connection between the fixing part and the actuating element
Data Source
Figure 1a~1b
Figure 2a~2b
Figure 2c~2d
AI summary
A passive strain sensor (C2) includes a system for detecting a variation in the distance between two points or regions of a structure, and a carrier (1) having first and second portions (1a, 1b) configured for attachment to said points or regions. Said system comprises a measuring assembly (13) carried by the first portion (1a) and actuatable only in one measurement direction to measure and store a measurement associated with at least one strain in a measurement direction, and an actuating device (12) comprising an intermediate assembly (15) with an actuating member (15c) of the measuring assembly (13), and an actuating assembly (14) having a push portion (14c) opposite the intermediate assembly (15) and configured such that the actuating member (15c) is moved relative to the measuring assembly (13) only when the second portion (1b) moves in the measurement direction.