Piezoelectric Bolt Loosening Detection With Temperature Compensation

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Solution Overview

Problem

Conventional bolt loosening detection methods are inaccurate due to the inability to account for the influence of ambient temperature variations, leading to reduced monitoring accuracy and misjudgment of bolt loosening in complex environments.

Innovation Solution

Perform temperature compensation processing on the characteristic values derived from bolt signals to eliminate the impact of ambient temperature variations, using piezoelectric sensors and signal processing to enhance detection accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional ultrasonic detection methods are used to monitor bolt loosening, then the detection process is simplified, but the monitoring accuracy decreases due to inability to account for temperature variations

Engineering Contradiction:

Improvemonitoring accuracyVSAvoidability to account for temperature variations

Core Design Contradiction:

Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The system performs preliminary temperature compensation by establishing a reference characteristic value at a reference temperature before actual detection. This preliminary action allows the system to pre-calculate compensation parameters that will be used during temperature variations, enabling accurate detection without real-time complex calculations.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system changes the parameter being measured from raw ultrasonic signal characteristics to temperature-compensated characteristic values. By transforming the detection parameter to account for temperature effects, the system maintains measurement precision across varying temperature conditions while using standard ultrasonic equipment.

Inventive Principle:

Principle #35Parameter changes

2Measurement precision

If temperature compensation processing is performed to eliminate temperature influence, then monitoring accuracy improves, but device complexity increases

Engineering Contradiction:

Improvedetection accuracyVSAvoidsystem complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The system replaces complex real-time temperature compensation mechanisms with a simplified approach using pre-calculated compensation parameters stored in memory. Instead of performing complex real-time calculations or using additional hardware, the system substitutes the compensation process with parameter lookup and simple mathematical operations based on current temperature readings.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system creates a reference model of the bolt connection at a known temperature state. This reference characteristic value serves as a template that is copied and adjusted based on temperature differences, allowing the system to compensate for temperature effects without requiring complex real-time analysis of the actual bolt state.

Inventive Principle:

Principle #26Copying

3Productivity

If real-time health monitoring is implemented to eliminate manual maintenance, then maintenance costs decrease, but detection accuracy is reduced due to temperature sensitivity

Engineering Contradiction:

Improvemaintenance efficiencyVSAvoiddetection accuracy

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

The system performs self-adjustment by automatically compensating for temperature effects using readings from the same piezoelectric sensor. The sensor serves both to detect bolt loosening and to sense temperature variations, allowing the system to self-correct without external intervention or additional complex sensing equipment.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The piezoelectric sensor performs multiple functions: it acts as both the ultrasonic excitation/reception element for detecting bolt loosening and as a temperature sensor for compensation. This multi-functionality allows real-time monitoring to maintain accuracy without requiring separate dedicated temperature sensing systems.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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

Improves the accuracy of bolt loosening detection by eliminating the influence of temperature variations, thereby preventing misjudgment and enhancing practical industrial applications.

Implementation Method 1

applying an excitation signal to a piezoelectric sensor provided on a bolted connection structure

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

detecting a signal delivered through a bolt

Methodology Applied

Scientific EffectPiezoelectric effect: Converse Piezoelectric Effect

Data Source

PatentUS20250305894A1Method and system for detecting bolt loosening

Publication Date: 2025.10.02 MURATA MFG CO LTD

AI summary

A method includes applying an excitation signal to a piezoelectric sensor on a bolted connection structure, detecting a signal delivered through a bolt, calculating, from a detected signal, a characteristic value of the signal delivered through the bolt, performing temperature compensation processing on the characteristic value based on an operating ambient temperature of the bolt, and detecting whether the bolt loosens based on the characteristic value on which the temperature compensation processing has been performed.