Bearing Diagnosis Using Acceleration Correlation Under Small Displacement

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Solution Overview

Problem

Existing methods for diagnosing bearing damage in bridges, such as those described in Non-Patent Document 1, can lead to erroneous results when the displacement amount of the bridge girder is small, making it difficult to accurately assess the state of the bearings.

Innovation Solution

A bearing diagnosis apparatus and method that utilizes first and second index information, derived from the response of a structure and the bearing to external forces, to calculate a feature amount that reflects the correlation between acceleration and displacement responses, allowing for accurate assessment of bearing condition.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the ratio between displacement amount of bridge girder and displacement response of bearing is used for diagnosis, then bearing damage can be diagnosed, but erroneous diagnosis occurs when displacement amount is small

Engineering Contradiction:

Improvebearing damage diagnosis accuracyVSAvoiddiagnosis reliability under small displacement

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The invention changes the diagnostic parameters from displacement-based measurements to acceleration-based measurements. Specifically, it uses the ratio of acceleration at the bearing to acceleration at the bridge girder, which remains effective even when displacement amounts are small. This parameter transformation resolves the contradiction by maintaining diagnosis accuracy across different displacement conditions.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

Instead of directly measuring displacement ratios, the invention inverts the approach by measuring acceleration ratios and using the relationship between acceleration and displacement through differential equations. This indirect measurement approach allows accurate bearing diagnosis even when direct displacement measurements are too small to be reliable.

Inventive Principle:

Principle #13The other way round (Inversion)

2Loss of information

If displacement measurement is used for bearing diagnosis, then bearing state can be assessed, but it becomes difficult to monitor ratio changes when displacement amount is small

Engineering Contradiction:

Improvebearing state informationVSAvoidratio change detection difficulty

Core Design Contradiction:

Loss of informationVSDifficulty of detecting and measuring

Solution Approach 1:

The invention transforms the measurement parameter from displacement to acceleration. By measuring acceleration at both the bearing and bridge girder, and calculating their ratio, the system can effectively monitor bearing state changes even when displacement amounts are too small to provide reliable diagnostic information.

Inventive Principle:

Principle #35Parameter changes

3Ease of operation

If simple displacement ratio method is used, then diagnosis process is simple, but diagnosis accuracy decreases for small displacement structures

Engineering Contradiction:

Improvediagnosis process simplicityVSAvoiddiagnosis accuracy

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

The invention maintains operational simplicity by using a ratio-based approach similar to the original displacement method, but changes the measured parameter to acceleration. This allows the system to retain the ease of ratio calculation while achieving accurate diagnosis even for structures with small displacement responses.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS12352653B2Bearing diagnosis apparatus, bearing diagnosis method, and computer readable recording medium

Publication Date: 2025.07.08 NEC CORP

AI summary

A bearing diagnosis apparatus 1 that accurately diagnoses the state of a bearing includes: an extraction unit 2 configured to extract a feature amount using first index information indicating a response of a structure 21 to an external force and second index information indicating a response, to the external force, of a bearing 23 provided to the structure 21; and an assessment unit 3 configured to assess the state of the bearing 23 based on the extracted feature amount.