Resonant Strain Sensor for Elastomer Components

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Solution Overview

Problem

Existing RFID transponders for strain measurement in elastomeric components face challenges due to high energy requirements, structural disruption, and early failures under dynamic loads, making them unsuitable for elastomeric products like drive belts, and they cannot withstand vulcanization processes.

Innovation Solution

A strain sensor with a high-frequency resonator embedded or applied to the elastomer component, which changes its natural frequency in response to mechanical strains, allowing for wireless detection using a control unit that excites the resonator and determines strains from its vibration behavior, eliminating the need for a power source and minimizing structural interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If RFID transponders with electronic assemblies are integrated into elastomeric components, then strain measurement capability is achieved, but the electronic components disrupt the structure of the elastomeric product and cannot withstand vulcanization conditions

Engineering Contradiction:
Improvestrain measurement capabilityVSAvoidstructural integrity and vulcanization resistance
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent replaces electronic measurement systems (RFID transponders with electronic assemblies) with a purely mechanical resonator system. The resonator's natural frequency changes in response to mechanical strain, eliminating the need for electronic components that disrupt the elastomeric structure or cannot withstand vulcanization. This substitution maintains measurement capability while resolving structural and processing reliability issues.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The resonator is designed as a simple, inexpensive mechanical element that can be easily integrated into the elastomeric component. Rather than using complex, expensive electronic assemblies vulnerable to failure, the patent employs a robust mechanical resonator that tolerates the harsh conditions of elastomer processing and application, effectively replacing fragile electronic components with durable mechanical ones.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

2Measurement precision

If strain gauges are used for measurement, then accurate strain detection is achieved, but high energy requirements lead to frequent querying and protocol adjustments

Engineering Contradiction:
Improvestrain detection accuracyVSAvoidenergy consumption
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent employs a resonator that operates at its natural frequency to detect strain. By exciting the resonator and measuring its vibrational response, the system achieves accurate strain detection through mechanical resonance rather than electrical measurement. This approach significantly reduces energy consumption compared to continuous operation of electronic strain gauges, as the resonator only requires periodic excitation.

Inventive Principle:
Principle #18Mechanical vibration

Solution Approach 2:

Instead of continuous monitoring requiring frequent querying, the patent uses periodic excitation of the resonator at its natural frequency. The resonator's response to this periodic excitation provides strain information, eliminating the need for continuous energy consumption and frequent protocol adjustments associated with electronic strain gauge systems.

Inventive Principle:
Principle #19Periodic action

3Ease of operation

If RFID transponders are used in dynamically loaded elastomeric products, then wireless strain measurement is achieved, but the electronic components fail early under dynamic loads

Engineering Contradiction:
Improvewireless operationVSAvoidoperational lifespan under dynamic loads
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent replaces the electronic RFID transponder system with a mechanical resonator system that inherently tolerates dynamic loads. The resonator's mechanical construction and integration with the elastomeric component allow it to withstand repeated flexing and loading cycles that would cause electronic components to fail, while maintaining wireless operation through non-contact excitation and detection.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 continuous, precise, and sensitive detection of mechanical strains in elastomeric components without disrupting their structure, allowing for flexible integration and long-term operation, even under dynamic conditions, with improved measurement sensitivity and reduced energy consumption.

Implementation Method 1

at least one resonator whose natural frequency is dependent, preferably at least essentially linearly, on the mechanical strains to be detected

Methodology Applied
Scientific EffectResonance: Resonance

Implementation Method 2

the control unit is designed to excite the resonator to oscillate at its natural frequency and to detect vibrations

Methodology Applied
Scientific EffectVibration: Vibration

Data Source

PatentEP4015985A1Device for detecting mechanical strains in or on an elastomer component and strain sensor therefor
Publication Date: 2022.06.22 CONTITECH DEUTSCHLAND GMBH
  • EP4015985A1 patent drawingFigure 1~2
  • EP4015985A1 patent drawingFigure 3
  • EP4015985A1 patent drawingFigure 4

AI summary

The present invention relates to a device for detecting mechanical strains (A) in or on an elastomer component (3), comprising an elastomer component (3) with at least one strain sensor (1), wherein the strain sensor (1) has at least one resonator (10) whose natural frequency depends on the mechanical strains (A) to be detected, preferably at least substantially linearly, wherein at least the resonator (10) is embedded in or applied to the elastomer component (3) such that mechanical strains (A) acting on the elastomer component (3) can change the natural frequency of the resonator (10), and comprising at least one control unit (2) configured to excite the resonator (10) to vibrate at its natural frequency and to detect its vibrations, wherein the control unit (2) is further configuredto determine the mechanical strains (A) of the elastomer component (3) from the recorded vibrations of the resonator (10).