Non-Invasive Pipe Strength Estimation via External Vibration Analysis

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Solution Overview

Problem

Existing methods for inspecting the deterioration state of buried pipes, particularly water-filled pipes, are challenging due to the difficulty in accessing the inside of the pipe for assessment.

Innovation Solution

An estimating device comprising a frequency response calculating unit, a pipe rigidity variable estimating unit, and a strength estimating unit that calculates the pipe's frequency response function and estimates its rigidity and strength using external accessories and sensors to measure vibration responses and excitation forces, allowing for non-invasive assessment of pipe condition.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If inspection is performed from the inside of the pipe, then deterioration state can be inspected with high accuracy, but it becomes difficult to apply to water-filled pipes where the inside is filled with fluid

Engineering Contradiction:
Improvedeterioration inspection accuracyVSAvoidapplicability to water-filled pipes
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The patent inverts the traditional inspection approach by moving from internal inspection to external inspection. Instead of placing sensors inside the pipe to directly measure deterioration, the patent attaches sensors to the external surface of the pipe and measures vibration responses caused by impact elastic waves, thereby enabling inspection of water-filled pipes without internal access.

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The patent introduces impact elastic waves as an intermediary medium to transmit information about pipe deterioration from the internal structure to external sensors. The elastic waves propagate through the pipe wall and carry characteristics of the pipe's mechanical properties, allowing indirect measurement of deterioration state through external vibration analysis.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If impact elastic wave test is performed to inspect buried pipes, then high accuracy deterioration inspection is achieved, but the method is complex and difficult to apply to various pipe types

Engineering Contradiction:
Improvedeterioration inspection accuracyVSAvoidinspection method complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent develops a universal inspection method that can be applied to various types of pipes (metal pipes, ceramic pipes, plastic pipes) and different pipe sizes and shapes. The external vibration response measurement approach with impact elastic waves provides a multi-functional inspection capability that works across diverse pipe configurations without requiring type-specific complex procedures.

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

Enables easy and accurate estimation of the strength of water-filled pipes, even when buried underground, by analyzing vibration responses and excitation forces, providing a reliable method for assessing pipe integrity.

Implementation Method 1

a vibration response of the pipe and a fluid inside the pipe to the excitation, wherein the vibration response is caused by an elastic wave generated by the excitation and propagating through the fluid inside the pipe and the pipe

Methodology Applied
Scientific EffectElastic wave: Sound

Data Source

PatentEP3708992B1Estimating device, estimating method, and program storing medium
Publication Date: 2024.10.16 NEC CORP
  • EP3708992B1 patent drawingFigure 1
  • EP3708992B1 patent drawingFigure 2
  • EP3708992B1 patent drawingFigure 3A~3B

AI summary

In order to provide an estimating device and the like capable of easily estimating the strength of a pipe, this estimating device is provided with a frequency response calculating unit, a pipe rigidity variable estimating unit, and a strength estimating unit. The frequency response calculating unit calculates a frequency response function of the pipe on the basis of excitation force data representing an excitation force when the pipe is excited, and response data obtained by measuring vibrations propagating through the pipe. The pipe rigidity variable estimating unit estimates a parameter relating to the rigidity of the pipe on the basis of a frequency response function model, which is a model representing the frequency response of the pipe, and the frequency response function. The strength estimating unit estimates the strength of the pipe on the basis of a relationship between the parameter and the strength of the pipe.