Deriving Train Count from Bridge Vibration Frequency and Passing Period
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Solution Overview
Problem
Existing methods for diagnosing the state of social infrastructure structures, such as railway bridges, are inadequate in determining the number of moving objects, like railway trains, with a lower computational load and without resorting to extensive inverse analysis.
Innovation Solution
A derivation method and system that acquires time-series data from a structure in response to a moving object, derives the fundamental frequency and passing period from this data, and calculates the number of moving objects based on environmental information, fundamental frequency, and passing period.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If inverse analysis method is used to obtain unknown parameters, then structural performance can be evaluated, but calculation amount becomes enormous
Solution Approach 1:
The patent extracts only the essential parameters needed for structural performance evaluation (number of moving objects, passing period, fundamental frequency) from the complex inverse analysis, eliminating unnecessary calculations while preserving measurement precision
Solution Approach 2:
Instead of using complex inverse analysis to derive structural parameters from acceleration data, the patent inverts the approach by directly calculating the number of moving objects from easily obtainable parameters (passing period and fundamental frequency), thereby simplifying the computational process
2Loss of information
If existing methods are used to determine number of moving objects, then diagnostic information can be obtained, but computational load remains high
Solution Approach 1:
The patent performs preliminary calculations by first determining the passing period and fundamental frequency from acceleration data, which are then used to directly calculate the number of moving objects, avoiding the need for computationally intensive inverse analysis
Solution Approach 2:
The patent changes the parameters used for calculation from complex structural parameters requiring inverse analysis to simpler parameters (passing period, fundamental frequency) that can be derived more efficiently while still providing accurate information on the number of moving objects
Data Source
AI summary
A derivation method includes: an acquisition step of acquiring time-series data including a physical quantity generated at a predetermined observation point in a structure as a response caused by a movement of a formation moving object formed with one or more moving objects on the structure; an environment information acquisition step of acquiring, as environment information, information on a structure length that is a length of the structure, a moving object length that is a length of the moving object, and an installation position of a contact portion of the moving object with the structure; a fundamental frequency derivation step of deriving a fundamental frequency of the time-series data based on the time-series data; a passing period derivation step of deriving a passing period during which the formation moving object passes through the structure based on the time-series data; and a number derivation step of deriving the number of the moving objects included in the formation moving object based on the environment information, the fundamental frequency, and the passing period.